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What is Grinding?

Descripción: Grinding takes an abrasive — often attached to a grinding wheel — and uses its many grains to cut a workpiece. Variations on this process are useful for a wide variety of applications.     On its surface, grinding seems simple: a machine takes a rotating tool (usually a wheel) with abrasive grains and applies it to a workpiece’s surface to remove material. Each grain is its own miniature cutting tool, and as grains dull, they tear from the tool and make new, sharp grains prominent.     But there are many variations, approaches and considerations for this type of machining, each of which is particularly effective for certain applications with certain materials.     Principles of Grinding     In all forms of grinding, three different interactions occur between the abrasive and the machined material. Cutting occurs where the abrasive grain is sufficiently exposed to penetrate the workpiece material and curl a chip, and sufficient clearance exists between the grain, bond and workpiece to flush the chip with coolant or throw it away by wheel action. Plowing takes place when the grain is unable to get enough penetration to lift a chip, instead pushing the material ahead of the abrasive edge. Sliding happens when a lack of cut depth, insufficient clearance or a grit staying on the wheel after dulling results in rubbing or creating slide marks on the workpiece surface. Grinding process control balances these three interactions to achieve the desired parameters.     These interactions feed into three major commercial grinding processes: rough grinding, precision grinding and ultra-precision grinding. Rough grinding maximizes the metal removed at the cost of surface finish. It primarily sees use in cutting off billets, grinding weld beads smooth and snagging gates and risers from castings. Additional surface finishing passes typically take place afterward — in particular, a “spark-out” pass relieves some of the stress on the machine tool and uses plowing to impart a better surface finish and size tolerance. Precision grinding is a middle-ground between metal removal and part size control, and serves as the basis for creep feed grinding, slot grinding and high-efficiency deep grinding. In ultra-precision grinding, little to no actual cutting occurs, but sliding action from very fine grains rubs the workpiece surface to a high finish. Most surface finishing processes, such as lapping and polishing, are examples of this type of grinding.     Hundreds of different variables can affect the interaction between the abrasive and the workpiece, but they generally come down to machine tool, work material, wheel selection and operational factors. Balancing these by setting up a part run that fits within the known parameters of all four categories provides a baseline that gradual parameter adjustment can improve.     Grinding Wheels     Grinding wheels have two major components: the abrasive grains and the bond. The relative percentages of grain and bond, and their spacing on the wheel, determine the wheel’s structure. Different types of grains work better on different projects, as do different types and “grades” (i.e. strengths) of bond. Broad areas of grinding need coarser grits and softer grades, with smaller areas requiring finer grits and harder grades to withstand the greater unit pressure.     Straight wheels are the most traditional type of grinding wheel, with the grinding face on the periphery of the wheel. Recessed wheels are variations on this form, featuring a recessed center to fit on a machine spindle flange assembly. The other major type of wheel shape uses a cutting face on the side of the wheel — names for this type of wheel include cylinder wheels, cup wheels and dish wheels, depending on the particular shape. For these wheels, bonded abrasive sections of various shapes, also known as “segments,” are assembled to form a continuous or intermittent side grinding wheel.     Operational Basics     Although speeds for grinding wheels and cutting wheels are measured in sfm or smm, wheels are often rated in rpm. It is important never to operate a grinding wheel over its rpm limit — most experts recommend never mounting a wheel on a machine that can exceed the wheel’s limit.     As speeds increase, each grain cuts and wears less. This emulates a harder grade. Vitrified bonds work up to 6,500 sfm, with organic bonds handling up to around 9,500 sfm. Higher speeds will require specially made grains.     Work speed defines the speed at which a grinding wheel passes over a workpiece or rotates around a center. High work speeds lower the heat retention and reduce the risk of thermal damage. Both high work speeds and reducing the diameter of the wheel result in increased grain depth of cut, performing like a softer grade wheel.     Traverse distance, or crossfeed, is the distance a workpiece moves across the face of the wheel. Lowering the traverse distance to no more than one-quarter of the wheel width improves surface finish, but slows down productivity. Increasing the crossfeed to one-half the wheel’s width or above boosts productivity, but lowers surface finish.     Different types of grinding use different methodologies to determine the work material removal per unit of width, but one consistently useful metric for shops is the grinding gratio, or g-ratio. This is the ratio of volume of work removed to volume of wheel consumed (or, volume of work removed ÷ volume of wheel worn). From a cost standpoint, a higher g-ratio is better.     Types of Grinding     Grinding operations come in many types, with this article covering six major types and several of the subtypes within.     Cylindrical grinding is a common type of grinding in which both the wheel and the workpiece rotate. The workpiece is either fixed and driven between centers, or driven by a revolving chuck or collet while supported in a center. This operation can take place with either traverse movements, where the wheel traverses axially along the part, or plunge movements, where the wheel is thrust into the part. Straight wheels are most commonly used in cylindrical grinding, with common cylindrical grinding machines being plain cylindrical (or roll) grinders, centerless grinders and inside- or outside-diameter grinders. Internal cylindrical grinding does the internal diameter grinding of bores and holes, generating size and concentricity within millionths of an inch. The grinding wheels tend to range in diameter from half an inch to three inches. This small size introduces rapid wear, making CBN and diamond wheels in crush dressable and vitrified form popular for these applications.     Surface grinding, such as stainless steel grinding, involves grinding a plane surface by feeding the workpiece beneath a rotating grinding wheel. Like cylindrical grinding, it operates in two general formats. The workpiece may travel traversely under the wheel and move back and forth beneath a grinding wheel mounted on a horizontal spindle, or it may move in circles on a rotary table beneath a vertical spindle that cuts on the face of the grinding wheel or grinding segment. Applications for this grinding type may grind a surface flat or introduce grooves by grinding straight channels into the workpiece. While milling can complete these tasks, grinding improves surface finish, has less expensive tooling and allows contours to be dressed into the profile of the wheel — making it much more cost-effective for very hard or abrasive surfaces.     Centerless grinding creates cylindrical forms at extremely close tolerances. This type of grinding eliminates the need for center holding by supporting the workpiece at three separate points: the grinding wheel, feed wheel and work support blade. Nothing actually clamps the workpiece in place, so each piece flows freely for continuous production (also known as “throughfeed centerless grinding”). The grinding wheel, during ordinary metal grinding, and the feed wheel rotate in the same direction, while the workpiece rotates in the opposite direction between them. The rotation keeps the workpiece down, while the work support blade (slightly angled to raise the workpiece above the centerline for better cylindricity) holds it up. The work support blade should always be at least as long as the grinding wheel is wide. Centerless grinding also comes in three forms. Throughfeed centerless grinding is used on straight cylindrical workpieces without interfering shoulder or projections, and involves the offset axis feed wheel feed the workpiece past the grinding wheel to a discharge position. Infeed grinding (also called plunge centerless grinding) is best when a workpiece has projections, irregular shapes, varying diameters or shoulders, and works best for profiles and multi-diameter workpieces. In this submethod, feed wheels above the grinding wheel feed the workpiece downward, with no lateral movement during grinding. Endfeed centerless grinding grinds conically tapered cylindrical sections like shanks on A and B taper drill bits. Here, the feed wheel, grinding wheel and work blade are set up in a fixed relationship to each other, then two wheels are dressed to a shape matching the end taper of the workpiece and the workpiece is fed from the front of the grinding machine until it reaches an end stop.     Creep feed grinding is a slow, one-pass operation that makes a deep cut of up to one inch in steel materials at low table speeds between 0.5 and 1 ipm. It is not suitable for conventional grinding machines, but for those which are compatible with it, it offers high productivity and cost effectiveness. Creep feed grinding is a plunge operation with high horsepower requirements, and which also requires a heavy flow of cutting fluid close to the nip to remove chips and cool the work. Continuous dressing at about 20 to 60 millionths per revolution — preferably with a diamond roll — reduces cutting times of fixed machine cutting and keeps the wheel sharp. When a second pass is required, it is typically of no more than 0.002 inch deep to “clean up” the workpiece.     Snagging is a rough grinding application that removes unwanted metal with little consideration of surface finish. As such, it uses durable straight and straight cup wheels in horizontal and straight shaft grinding machines, although flaring cup wheels are used in right-angle grinders and various round and square-tipped cones and plugs also see use. Typical applications include removing unwanted metal on castings; removing flaws and cracks; removing gates, risers and parting lines; rough beveling; grinding down heavy welds; and preparing surfaces for cleaning or painting.     Cut-off operations use an abrasive wheel as an alternative to the laser, abrasive water jet, metal saw, friction saw and oxyacetylene or plasma arc torch. A study from Norton Abrasives demonstrated that the abrasive wheel can outperform these other methods with ferrous materials, and that the abrasive wheel is faster and less expensive for nonferrous materials than the common metal saw choice. The abrasive wheel provides more cutting points than a saw, and cuts just as thoroughly at a speed of 2 or 3 miles per minute. Cut-off wheels should run at the highest possible speed, with one horsepower for every inch of wheel diameter. If this proves impossible, use a softer wheel. Production jobs use non-reinforced wheels, with non-reinforced shellac wheels for applications requiring extreme versatility and quality of cut. Reinforced wheels are compatible with portable cut-off, swingframe, locked head push-through and foundry chop stroke operations.

Fecha de Publicación: 03-09-21

Key Door Hardware Components for Safety and Security

Descripción: Understanding door hardware options and opportunities is the first step in turning threats and weaknesses into strengths. Entry doors with window mesh might be in bad condition, with broken closers, loose hinges, doors that sag or are sticking, latches that do not align properly with the strike, and wide gaps between the door and frame that pry open easily. Other access points might use old technology.     Poorly maintained hardware offers the easiest path for unauthorized entry. Old technology is next and soon might become a weakness. Vendors know the best options for meeting ASTM/BHMA standards for the manufacture and testing commercial grade hardware. ANSI Grade 1 hardware is specifically designed for high-traffic areas because it can withstand the highest number of life cycles and is much harder for an active shooter to break through.     Upgrades that deliver greater safety and security include replacing Grade 2 and 3 components with Grade 1 hardware. A further upgrade involves integrating the latest generation of commercial electronic UPVC door locksets, closers, hinge hardware and alarms with a central control system.     Managers need to pay special attention to levels of access to facilities. Authorized personnel need access and, in emergency situations, rapid and safe egress, while unauthorized personnel have to be kept out. Firefighters and other emergency personnel need ease of entry to locate and evacuate people rapidly.     Increasingly, managers are installing card and PIN UPVC door lock systems, and they are rearranging traffic flows to channel visitor traffic at elevator lobbies toward properly staffed, secure reception areas. Only authorized personnel should be able to enter the main building through locked lobby doors.     Among the most common door hardware components upgraded for improved security are the following:     Closers.      Standard and custom door closers include surface-mounted and hidden, heavy-duty closers for high-cycle or windy and drafty conditions, as well as ADA-compliant maximum-force-to-operate closers. A closer’s open cycle compresses the spring and positions the fluid through the open valve for closing. The delay valve allows slower-moving traffic to pass. The closing valve slows closing speed to within 6 inches of the stop. The latching valve accelerates closing for the last 6 inches. Closers need regular adjustment to keep the cycles operating as designed.     Hinges. (UPVC door window hinges)     By removing the hinge pins, an attacker can gain access to a facility through a hinged door with window hinge, even when it is locked. Removing a screw and inserting a special pin prevents an attacker from removing the door from its frame, even if door hinge pins are removed.     Locksets.      Deadbolts, knobs, lock cylinders, levers, and entry handsets are wired and wireless devices that operate via remote-open and turn-on devices and cell phone applications. Replacing mechanical keyed locksets with electro-mechanical locks in the same housing is a low-cost upgrade option. Managers are using electronic remote-controlled devices, such as door roller, cameras, motion sensors, and tamper alarms, to give early warning.     They also can upgrade unguarded remote entry points from mechanical locks and keys to systems that incorporate CCTV and sound. A security guard at a remote point directs the person seeking entry to place his or her badge in front of the camera, verifies the person has the proper clearance and is the same person as shown on the picture badge, and remotely actuates the lock allowing entry.     In an emergency requiring rapid evacuation of the building, all evacuation route doors with window roller are remotely unlocked immediately and simultaneously from a central control. Other common upgrades include the installation of biometric fingerprint readers, facial-recognition systems, and floor-to-ceiling locked turnstiles.     Alarms. Radio-wave tamper alarms can be activated by a vehicle or a person moving through and disturbing a radio wave field. The power source sends radio waves through the antenna surrounding anything the antenna touches , including a door, window door hand tools, fence, vehicle, or unattended building. Audio alarms can be attached or silent-connected to a police station or can activate CCTV or access -control systems.     Cybersecurity. An organization’s access control computer must have no internet route that might allow hackers to take control. Experts advise preventing malware attacks through Wi-Fi that blocks phishing and spear phishing and prevents malware entry into a system. A cybersecurity expert can a wise safeguard against such attacks.     The list of upgrades might exceed what managers can implement immediately because of cost or time constraints. One effective strategy is to start at the top of the organization’s priority list and work down as far as possible this year, updating the list for budgeting year after year. The main take-away from a successful security strategy is the safety of occupants, but the payback also can include lower lost-opportunity costs and better continuity of normal operations.

Fecha de Publicación: 03-09-21

Importance of Using Paper Bags

Descripción:     Carrybags has  become  a  more  convenient way  to  carry  daily  necessities  and  for  packaging  in small quantities. The well-known form of such bags is in the form of plastic bags. Despite of all known hazards of plastic pollution, it’s prevalent and pervasive in India. Plastic bags are one  of the worst and  most unnecessary plastic polluters of the earth. Plastic bags are used on a large  scale  by  retailers  for  a  simple  reason  that  plastic bags  are  much  cheaper  than  paper,  cloth  or  other  eco-friendly  bags. This  paper  presents  the  designing  and development  of  asystem  to automate  the  procedure  of paper bags production so as to make its production cost comparable  to  plastic  bags  and  inherently  increase  its production  rate  so  as  to  fulfill  the  ever  increasing demand.  We have  used  micro-controller  based  design approach  which  has  kept  the  cost  of  the  system significantly low as compared to PLC based designs and have automated the manufacturing process.     We  need  small  size  bags  every  day  for  various purposes  like  grocery,  fruits,  and  vegetables.  We  use plastic  bags  for  such  purposes.  Plastic  shopping  bags have  a  surprisingly  significant  environmental  impact for    something    so    seemingly innocuous.    Plastic shopping  bags  kill  large  numbers  of  wildlife  each year.  One  of  the  most  dramatic  impacts  is  on  marine life.So  to  avoid  above  harmful  effects  of  Plastic  Bags, viable  alternative  is  required  which  is  Paper  Bag. Actually,  Paper  Bag  is  being  used  but  in  very  small scale.  Conventional  Paper  Bags  requirespecial  paper which  increases  the  overall  cost  of  the  Paper  Bag. This is the main cause due to which use of Paper Bag is  less.  Also  initial  investment  cost  is  very  much  in conventional paper bag making machine. So it cannot be used for small scale production.All  these  problems are  eliminated  in the  presented machine. Amachine  whose  initial  cost is  less,  which does not require any special paper, which can be used for small scale production, is developed. Thismachine willhelp  a  poor  family  to  earn  money  through  small scale production of paper bags.     Paper bags have been gaining popularity since then plastic bags have been banned in various countries and cities. The product is made in two ways; traditionally, i.e. manual which is a manual or technical means i.e. with the help of automated equipment. The second method is much larger. In other words, it requires less workers and more money to buy land and equipment. Based on the core business of nonwoven bag making machine Manufacturers, the machine has 2 different output capabilities with good finish and seamless quality.     Amazing Benefits of Using a Paper Bag Production Machine: -     Excellent Quality: The great advantage of producing a paper bag from an automated machine is the excellent quality one can achieve throughout the production process. When we make paper bags in traditional ways, the quality of the product does not always match the whole production process. It is difficult to maintain the same level of quality per unit. Machine paper bags offer the same quality and precision each time.     Save on Work Expenditure: The introduction of an automated production process machine including slitting machine has reduced the need for workers in the paper industry. One only needs to change the paper roll and collect the finished product after the production process is completed. This saves unnecessary costs on jobs and you can invest in machinery and land instead of workers. Too much machinery and land can lead to a double standard of business production at the same time.     Distributed Production Level: Quality and fast production are two of the most important factors in any production process and automated production for the purpose of the product satisfies both of these factors while improving the quality of production. Save real time financially and increase your productivity compared to handmade methods. You can actually upgrade your product over time.     Energy Saving: An automated machine saves human energy and helps increase productivity. Both man and machine have different working powers. The machine can work more efficiently than man and requires fewer working breaks than man. You can have a good level of mechanical production. The machine can double your production rate at the same time. However, one can only increase the product because everyone has a different working capacity.     Paper bags are gaining importance as these bags are 100% reusable, recyclable and biodegradable and at the same time environment friendly and pose less threat to wildlife. it requires less energy for paper bags to be recycled than plastic bags. Paper bags have come a long way since their beginnings in the mid-eighteenth century when some paper bag manufacturers started developing paper bags that are more hardy and long lasting. The paper bags are generally box-shaped in design that allows them to stand upright and hold more goods. Corporates are using paper bags for promotions, seminars, product packaging and branding purposes.     By selecting high quality paper bag manufacturer can deliver recycled brown color paper bags in big and small quantities, regular and premium paper bags which add a professional touch that consumers love and appreciate. Besides, you can add your own custom brand to any paper bag to promote your business. Read on to discover the importance of paper bags.     1. Plastic bags cause environmental damage such as increase the level of air pollution. Plastic bags not only have adverse effects on our natural habitats, death of many animals. Plastic bags are not renewable and you need UV rays to destroy it, which is harmful for environment.Paper bags on the other hand are environment friendly and can be recycled.     2. Paper bags are usually made from wood. So, these bags can be produced into a new paper like newspapers, magazines or books. Waste papers are also biodegradable so they can be easily degenerate and do not pile up on dump sites.     3. You can also buy them at a very cheap price particularly if they are bought wholesale.     4. Possessing a paper bag is practical and you can use them to bring your groceries and the premium quality paper bags can be used as paper gift bags.     5. Most people nowadays prefer using paper bags because they are easy to carry, neat and can hold lot of items. It adds to your status symbol as they can be embossed and grained to enhance the look.     6. Paper bags are usually used extensively in malls and exhibitions for delivering over the counter products as research shows that paper bags contain at least 35% recycled material.     7. Corporates are nowadays using paper bags for promotions, seminars, product packaging, and branding purposes as they are competitively priced.     8. Paper bag manufacturers can help you to decide the right size and type of paper bags as per your project, budget and quantity.     9. You can choose paper bags with special properties that will seal the freshness and give an aesthetic look to your brand as offset and screen printing is possible.     10. When your product is properly packaged with premium quality paper bags, you can attract more customers which will help in promoting your brand to the targetaudience.     So, if you are ecofriendly and at the same time want to be ahead of your competitors, start using paper bags.

Fecha de Publicación: 03-09-21

The chemistry of cosmetics

Descripción: Cosmetics materials are not a modern invention. Humans have used various substances to alter their appearance or accentuate their features for at least 10,000 years, and possibly a lot longer.       Women in Ancient Egypt used kohl, a substance containing powdered galena (lead sulphide—PbS) to darken their eyelids, and Cleopatra is said to have bathed in milk to whiten and soften her skin. By 3000 B.C men and women in China had begun to stain their fingernails with colours according to their social class, while Greek women used poisonous lead carbonate (PbCO3) to achieve a pale complexion. Clays were ground into pastes for cosmetic use in traditional African societies and indigenous Australians still use a wide range of crushed rocks and minerals to create body paint for ceremonies and initiations.     Today, cosmetics are big business. According to the 2011 Household Expenditure Survey, conducted every five years by the Australian Bureau of Statistics, Australians spend around $4.5 billion on toiletries and cosmetic products every year. Cosmetic advertising, previously directed mainly at women, is now targeting a wider audience than ever.     What is a cosmetic?     In Australia, a cosmetic is defined under the Industrial Chemical (Notification and Assessment) Act 1989 as ‘a substance or preparation intended for placement in contact with any external part of the human body' (this includes the mouth and teeth). We use cosmetics to cleanse, perfume, protect and change the appearance of our bodies or to alter its odours. In contrast, products that claim to ‘modify a bodily process or prevent, diagnose, cure or alleviate any disease, ailment or defect’ are called therapeutics. This distinction means that shampoos and deodorants are placed in the cosmetics category, whilst anti-dandruff shampoos and antiperspirants are considered to be therapeutics.     Regulation and safety     In Australia, the importation, manufacture and use of chemicals—including those used in cosmetics—are regulated by the Australian Government’s National Industrial Chemicals Notification and Assessment Scheme (NICNAS). NICNAS works to ensure that chemicals used in consumer products do not cause significant harm to users or to the environment.     In the case of cosmetics, every ingredient contained within the product must be scientifically assessed and approved by NICNAS before being manufactured or imported into Australia and before they can be used in consumer products. Where appropriate, NICNAS sets limits on the level at which a chemical can be used in a product and also conducts reviews on chemicals when new evidence arises.     Cosmetic products that make an additional therapeutic claim (such as moisturisers that also lighten the skin) are regulated by a different organisation—the Therapeutic Goods Administration (TGA).     Cosmetics and other personal care items must also be labelled in accordance with the Trade Practices (Consumer Product Information Standards, Cosmetics) Regulations 1991. This regulation requires that all intentionally added ingredients are listed on the product label, and is enforced by the Australian Competition and Consumer Commission (ACCC).     What do cosmetics contain?     There are thousands of different cosmetic products on the market, all with differing combinations of ingredients. In the United States alone there are approximately 12,500 unique chemical ingredients approved for use in the manufacture of personal care products.     A typical product will contain anything from 15–50 ingredients. Considering the average woman uses between 9 and 15 personal care products per day, researchers have estimated that, when combined with the addition of perfumes, women place around 515 individual chemicals on their skin each day through cosmetic use.     But what exactly are we putting on our skin? What do those long names on the ingredient list mean and what do they do? While the formula of each product differs slightly, most cosmetics contain a combination of at least some of the following core ingredients: water, emulsifier, preservative, thickener, emollient, colour, flavors and fragrances and pH stabilisers.     Water     If your product comes in a bottle, chances are the first ingredient on the list is going to be water. That’s right, good old H2O. Water forms the basis of almost every type of cosmetic product, including creams, lotions, makeup, deodorants, shampoos and conditioners. Water plays an important part in the process, often acting as a solvent to dissolve other ingredients and forming emulsions for consistency.      Water used in the formulation of cosmetic materials is not your everyday, regular tap water. It must be ‘ultra-pure’—that is, free from microbes, toxins and other pollutants. For this reason your label may refer to it as distilled water, purified water or just aqua.     Emulsifiers     The term emulsifiers refers to any ingredient that helps to keep unlike substances (such as oil and water) from separating. Many cosmetic products are based on emulsions—small droplets of oil dispersed in water or small droplets of water dispersed in oil. Since oil and water don't mix no matter how much you shake, blend or stir, emulsifiers are added to change the surface tension with surfactant materials between the water and the oil, producing a homogeneous and well-mixed product with an even texture. Examples of emulsifiers used in cosmetics include polysorbates, laureth-4, and potassium cetyl sulfate.     Preservatives     Preservatives are important ingredients. They are added to cosmetics to extend their shelf life and prevent the growth of microorganisms such as bacteria and fungi, which can spoil the product and possibly harm the user. Since most microbes live in water, the preservatives used need to be water-soluble, and this helps to determine which ones are used. Preservatives used in cosmetics can be natural or synthetic (man-made), and perform differently depending on the formulation of the product. Some will require low levels of around 0.01%, while other will require levels as high as 5%.     Some of the more popular preservatives include parabens, benzyl alcohol, salicylic kojic acid, formaldehyde and tetrasodium EDTA  (ethylenediaminetetra-acetic acid).     Consumers who purchase ‘preservative-free’ products should be aware of their shorter shelf life and be conscious of any changes to the look, feel or odour of the product that may indicate it has gone off.       Thickeners     Thickening agents work to give products an appealing consistency. They can come from four different chemical families:     Lipid thickeners are usually solid at room temperature but can be liquefied and added to cosmetic emulsions. They work by imparting their natural thickness to the formula. Examples include cetyl alcohol, stearic acid and carnauba wax.     Naturally derived thickeners come, as the name suggests, from nature. They are polymers that absorb water, causing them to swell up and increase the viscosity of a product. Examples include hydroxyethyl cellulose, guar gum, xanthan gum and gelatin. Cosmetics with a consistency that is too thick can be diluted with solvents such as water or alcohol.     Mineral thickeners are also natural, and as with the naturally derived thickeners mentioned above, they absorb water and oils to increase viscosity, but give a different result to the final emulsion than the gums. Popular mineral thickeners include magnesium aluminium silicate, silica and bentonite.     The final group are the synthetic thickeners. They are often used in lotion and cream products. The most common synthetic thickener is carbomer, an acrylic acid polymer that is water-swellable and can be used to form clear gels. Other examples include cetyl palmitate, and ammonium acryloyldimethyltaurate.     Emollient     Emollients soften the skin by preventing water loss. They are used in a wide range of lipsticks, lotions and cosmetics. A number of different natural and synthetic chemicals work as emollients, including beeswax, olive oil, coconut oil and lanolin, as well as petrolatum (petroleum jelly), mineral oil, almond oil, glycerine, zinc oxide, butyl stearate and diglycol laurate.     Colouring agents/pigments     Ruby lips, smoky eyes and rosy cheeks; it is the purpose of many cosmetics to accentuate or alter a person’s natural colouring. A huge range of substances are used to provide the rainbow of appealing colours you find in the makeup stand. Mineral ingredients can include iron oxide, mica flakes, manganese, chromium oxide and coal tar. Natural colours can come from plants, such as beet powder, or from animals, like the cochineal insect. The latter is often used in red lipsticks and referred to on your ingredient list as carmine, cochineal extract or natural red 4.     Pigments can be split into two main categories: organic, which are carbon-based molecules (i.e. organic in the chemistry context, not to be confused with the use of the word to promote ‘natural’ or ‘non-synthetic’ or ‘chemical-free’ products) and inorganic which are generally metal oxides (metal + oxygen and often some other elements too). Inorganic should not be confused with ‘synthetic’ or ‘unnatural’ as most of the inorganic metal oxide pigments do occur naturally as mineral compounds.     The two most common organic pigments are lakes and toners.  The lake pigments are made by combining a dye colour with an insoluble substance like alumina hydrate. This causes the dye to become insoluble in water, making it suitable for cosmetics where water-resistant or waterproof properties are desired.     A toner pigment is an organic pigment that has not been combined with any other substance.     The inorganic metal oxide pigments are usually duller than the organic intermediate pigments, but are more resistant to heat and light, providing a longer-lasting colour.     Glimmer and shine     Shimmering effects can be created via a range of materials. Some of the most common ones are mica and bismuth oxychloride.     Cosmetic mica typically comes from muscovite (KAl2(AlSi3O10)(F,OH)2) also known as white mica. It naturally forms in flaky sheets and these are crushed up into fine powders. The tiny particles in the powders refract (bend) light, which creates the shimmering effect common in many cosmetics. Mica coated with titanium dioxide gives a whitish appearance when looked at straight on, but then produces a range of iridescent colours when viewed from an angle.     Bismuth oxychloride (BiClO) is used to create a silver grey pearly effect. This compound occurs naturally in the rare mineral bismoclite, but is usually produced synthetically and so is also known as synthetic pearl.     The size of the particles used to create pearly and shimmering looks affect the degree of glimmer the product has. The smaller the particle size (15–60 microns, where one micron is one millionth of a meter), the less lustrous the powder will be, and more coverage it gives. Larger particle sizes, up to 500 microns, give a more glittery lustre and are more transparent.     Fragrances     No matter how effective a cosmetic may be, no one will want to use it if it smells unpleasant. Consumer research indicates that smell is one of the key factors in a consumer’s decision to purchase and/or use a product.     Chemicals, both natural and synthetic, are added to cosmetics to provide an appealing fragrance. Even ‘unscented’ products may contain masking fragrances to mask the smell of other chemicals.     The term ‘fragrance’ is often a generic term used by manufacturers. A single listing of fragrance on your product’s ingredient list could represent dozens or even hundreds of unlisted chemical compounds which were used to create the final individual fragrance.      Manufacturers do not have to list these individual ingredients as fragrance is considered to be a trade secret.     There are over 3,000 chemicals used to formulate the huge range of fragrances used in consumer products worldwide. A comprehensive list has been published by the fragrance industry. All the ingredients on this list have passed the International Fragrance Association (IFRA) safety standards for use in commercial products. However, without knowing which individual ingredients went in to making up the fragrance of a product, consumers can find it difficult to make informed choices. If consumers are concerned they should look for fragrance free products and buy from companies that label their products more comprehensively.     Are cosmetics dangerous?     There’s nothing like a bit of controversy to generate some media buzz. For over a decade there have been recurring reports in both the media and on hundreds of internet sites relating to potentially toxic substances present in cosmetics (lead, mercury, parabens) and the dangers they pose to the public. Should consumers be worried? Are these claims backed up by reputable, published scientific research or have the findings been misinterpreted and exaggerated? Let’s take a look …     Parabens     Parabens are a class of chemicals commonly used as preservatives in food, therapeutic and cosmetic products. They are derived from para-hydroxybenzoic acid (PHBA), which occurs naturally in many fruits and vegetables. Parabens come in several forms: methylparaben, ethylparaben, propylparaben, butylparaben and isobutylparaben. They are the most widely used preservative in personal care products. This is because they are incredibly good at doing their job—keeping your products mould and bacteria free—and are also cost effective.     The use of parabens in cosmetics hit the media in 2004 after a research study conducted by Dr. Philippa Darbre of the University of Reading in England reported findings that 18 out of 20 breast cancer tissue samples contained parabens. As parabens can weakly mimic the actions of oestrogen, and as oestrogen can enhance tumour growth, this was thought to be a problem. The presence of parabens in breast tumours was picked up by the media and presented as evidence that parabens contribute to breast cancer. This was incorrect.     While the presence of parabens is notable, the study found no direct evidence that they had caused the cancer or contributed to its growth. Breast tumours have a large blood supply, so it is likely that any chemical found in the blood stream will be present in the tumour.     In a later statement to the media, Dr. Darbre, referring to her 2004 study, said ‘No claim was made that the presence of parabens has caused the breast cancers.’     There have since been dozens of studies undertaken around the globe on the safety of parabens, which time and again have exhaustively demonstrated that parabens are broken down, metabolised and excreted harmlessly from the body.     Currently, both in Australia and internationally, the science community consider the use of parabens in cosmetics to be safe.     In response to consumer demand, some companies have begun to manufacture paraben free products, which consumers can purchase if they are concerned.     Aluminium     Concerns regarding cancer are also linked to the use of aluminium in deodorants and anti-perspirants. In the early 2000s various news outlets reported apparent links between the use of antiperspirants containing aluminium and breast cancer. Similar reports connected the use of such products to the onset of Alzheimer’s disease. These supposed links have never been scientifically proven despite multiple studies.     Aluminium works to block the sweat ducts to reduce sweating. Some argue that this process prevents us from releasing toxins, causing them to build up within our lymph glands. However, breast cancer tumours do not originate in the lymph nodes, they start in the breast, and travel to the lymph nodes later. Another study found no difference in the concentration of aluminium between the cancer and the surrounding tissue.     Currently there is no clear link between the use of under-arm products containing aluminium and breast cancer.     Likewise, studies have shown no relationship between Alzheimer’s disease and deodorant/antiperspirant use. Every day, humans are exposed to aluminium through food, packaging, pots and pans, medicine and even air and water. The official position of both the Alzheimer’s Society (US) and Alzheimer’s Australia is that a link between environmental aluminium absorption and Alzheimer’s disease seems ‘increasingly unlikely’.     Despite these findings, some manufacturers have begun producing aluminium-free products for consumers who still hold concerns.     Triclosan     Triclosan was originally developed as an anti-bacterial agent for use in hospitals, primarily as a surgical scrub. However its usefulness has seen it increasingly added to a wide range of consumer products including deodorant, soap, toothpaste, cosmetics and general house-hold cleaning products. Triclosan is also used as a pesticide and can, under certain circumstances, break down into potentially toxic chemicals such as dioxins.     Triclosan hit the news in 2000 after findings published by the National Academy of Sciences (US) noted rising levels of the chemical being detected in the environment and its increasingly broad use in everyday products as concerns.       Studies conducted by scientists at the University of California found that prolonged exposure to triclosan causes liver fibrosis and cancer in laboratory mice. Other studies have suggested triclosan can disrupt hormones, impair muscle contraction and reduce bacterial resistance.     Whilst the over-use of triclosan in products warrants further study, Australian experts have highlighted its value and importance when used correctly and in moderation. Professor of Dental Science at the University of Queensland, Dr. Laurie Walsh, noted that the chemical has been proven to fight various conditions such as gingivitis, inflammation and bleeding gums.     In Australia, a full risk assessment conducted by NICNAS found no cause for public concern in general, though did recommend controls for maximum concentrations of triclosan (0.3%) in personal care and cosmetic products. At present, cosmetic products containing more than 0.3% triclosan must clearly carry the word ‘poison’ on the label—not the best marketing strategy for producers.     The American Food and Drug Administration (FDA) is planning to release an updated report on Triclosan in 2016, though in the interim consumers may look for triclosan-free products if they wish.      Formaldehyde     Formaldehyde is an organic compound with a wide variety of uses. Although commonly associated with embalming, it is also used in the manufacture of building materials, textiles, household cleaning products, plastics, cosmetics and personal care products. It also occurs naturally in a wide range of foods, for example the humble egg.     Formaldehyde is not typically used in its pure form, but altered slightly and listed under the name formalin. It works as a preservative to protect products from contamination.     Formaldehyde is classified as a Group 1 carcinogen (known to cause cancer in humans) by the World Health Organization International Agency for Research on Cancer. It can also cause skin and sensory irritation and breathing difficulties in people when inhaled, ingested or if it comes into contact with skin. So why is it still used in everyday products?     As with other chemicals, it is the concentration present in a product that is important. NICNAS has assessed formaldehyde and set maximum safe limits for its use in cosmetics. Oral products such as toothpastes may only contain up to 0.1 percent formaldehyde, while nail hardeners can have up to 5 percent. All other cosmetic products (such as shampoos and straightening solutions) can have up to 0.2 percent. At these low levels, the use of formaldehyde is deemed to be safe.     NICNAS has noted that people with particularly sensitive skin may still experience irritation even at these low concentrations.     In 2010, the Australian Competition and Consumer Commission (ACCC) conducted a survey of the formaldehyde concentrations of several cosmetic products that resulted in the voluntary recall of two products that contained unacceptably high concentrations of the chemical.     Phthalates     Phthalates (pronounced THAL-ates) are another group of chemicals found in some cosmetics that have been red-flagged by environmental groups. They are generally used to make plastic products soft and flexible but can also be found in cosmetics like nail polish, hair spray (to make the products less brittle or stiff) and perfumes.     Phthalates are produced from oil and there are more than 20 types in common use. As the various phthalates have different chemical structures, toxicity profiles and uses, their safety should not be generalised as a group, but looked at on an individual basis. Some studies have indicated that at high, recurring concentrations different phthalates can act as endocrine disruptors—this means they upset the hormonal balance in the body and can lead to developmental problems, particularly in males. Other studies have indicated there may be a link between phthalates and type 2 diabetes.     In response, the European Union and the United States have imposed bans on some types of phthalates for use in cosmetics. Research conducted in Australia has identified a small level of risk in relation to one phthalate, bis(2-ethylhexyl) phthalate or DEHP, and as a result NICNAS has prohibited products that contain DEHP above the prescribed level—this generally relates to children’s toys.      Lead in your lipstick?     News reports detailing levels of lead and other metals in lipsticks are persistent and recurring, but should consumers be worried? A 2013 study by the University of California Berkley examined the metal content of 32 different lipsticks. Researchers found traces of aluminium, manganese (which can cause neurological problems) and titanium in all the products they tested, while three-quarters of the products contained lead (which affects the nervous system, and can cause learning disabilities in children). Many of the lipsticks and lip glosses also contained nickel and cobalt, as well as cadmium and chromium—both known carcinogens.     Why would manufacturers add these ingredients to their products? The answer is—they don’t. They exist in the products as ‘impurities’, that is, they are present in other ingredients such as the wax, oils or the mineral pigments used in the formula. Because of the persistent nature of these substances and the fact they occur in the natural environment, including in water, it is almost impossible to remove all traces of them.     However don’t throw your lippy away just yet. The presence of these naturally-occurring elements in lipsticks is not necessarily a problem—the important issue is the level or concentration. Are the the levels high enough to be considered toxic, or are they low enough to be deemed safe? Remember, sunlight is also a proven carcinogen (skin cancer)—but you still go outside and you might even sunbathe. It all comes down to dose.     With the exception of chromium, the study concluded that the metal concentrations were comfortably within the ‘acceptable daily allowances’ as determined by the researchers via a comparison with accepted water and air contamination levels. Basically, you will consume more lead from drinking water than you will from applying lipstick. However, the study did conclude that further research into the metal content of cosmetic products is necessary, particularly with respect to chromium.     Sun creams     While sun creams are not officially cosmetics (they are considered to be therapeutics), we will include them here as their use is so common, particularly in Australia.     Sunscreens play an important role in protecting our skin from the harmful UVA and UVB rays emitted by the sun. Their use has been proven to help prevent certain skin cancers including melanomas and basal cell carcinomas.       In recent years there has been some concern about nanoparticles (NP) in sunscreens. This relates particularly to zinc oxide (ZnO) and titanium dioxide (TiO?) nanoparticles and their ability to penetrate the skin to reach cells and the potential toxicity exerted by these chemicals.     The position of the Therapeutic Goods Administration (TGA), based on several published papers (up to May 2013) as well as reviews of international authorities, is that nano-particles are safe. ‘Several in vitro and in vivo studies using both animal and human skin have shown that these NPs do not penetrate the underlying layers of skin, with penetration limited to the stratum corneum. This suggests that systemic absorption is unlikely.’     A further study published in 2014 found that when exposed to zinc oxide nanoparticles, human immune cells (called macrophages) effectively absorbed the nanoparticles and broke them down.     Based on current evidence, neither TiO2 nor ZnO nanoparticles are likely to cause harm when used as ingredients in sunscreens. There are more risks associated with avoiding suncreams (sunburn, skin cancers) than there are posed by nanoparticles.

Fecha de Publicación: 03-09-21

Here's the Truth About Wood Veneers

Descripción: When you learn that a piece of furniture has a veneer, does it make you cringe a little? Admittedly us, too. But wood veneers, in fact, are a traditional and structurally significant aspect of furniture-making that still come into play in contemporary design.  Wood veneers have been used in furniture-making and millwork techniques for over 200 years,  says interior designer Cate Caruso, of Studio C, who uses them for all kinds of high-quality custom furnishings. In woodworking, a veneer is actually a  paper thin  cut of wood that's applied to both sides of a strong core surface, like furniture-grade MDF or substrate material, to seal and stabilize it—which is critically important when you're fashioning built-in furniture or anything with a mechanism. The reason is simple: Solid wood expands and contracts as the temperature changes, and your apartment isn't temperature controlled no matter how powerful your A.C. unit is. A dining table, for instance, can be made from solid wood (and many are), but a wood piece with moving parts cannot.  With kitchen cabinetry, drawers, and anything built-in or paneled, you really have to have veneers,  Caruso explains.  A solid piece of wood just isn’t always structurally sound enough to fabricate a millwork.      What she is not using is fake wood.  Oftentimes, when people see a veneered furnishing that’s cheap, it’s actually not wood at all—it’s a laminate material,  Caruso explains, putting a name to the faux surface that gave all veneers a bad rap somewhere along the line. (Those are made from plastic, paper, or even foil that's been printed with a wood grain pattern that often wears away at the edges—a sure way to spot them.) But of course, there's also a range in quality of proper veneers depending on who makes them.  All woodworking can be done well or it can be done poorly—but an expert millworker will make veneers look seamless, with perfect corners,  Caruso says, which explains the  misconception that a wood engineered veneer is cheap when it’s anything but.      Besides keeping a wood panel stable, veneers have other perks and purposes. They're considered an environmentally conscious option because  you're maximizing that log in thin little sheets,  Caruso says,  and then the core is furniture grade MDF or substrate material.  In extreme cases, they can even be cost-saving.  Think about Brazilian rosewood, which is rare, endangered, very hard to get, and very expensive,  says Patrick Muecke, Caruso's general contractor, who was a millworker for 15+ years before opening his own GC and management company.  If you want to do a rosewood paneled room in solid wood, you’d have to be the Sultan of Brunei in order to afford it.  The same would go for any project in an expensive wood; veneers would bring down the cost. Beyond millwork, natural bamboo veneers are also required for certain special techniques: Book-matched wood doors (or book-matched wood anything) would have to be fashioned using bamboo veneers because you'd never find wood planks with grains that perfectly match—it's necessary instead to have a series of veneers cut from the same log. Then there are labor-intensive inlay arts like marquetry and parquetry, which require veneers cut to certain sizes and shapes that are then fit into the top of a structure. A far cry from laminate surfaces, right?     When you’re choosing your residence hall furniture and deciding on the specs, you’ll inevitably choose what materials you want.     Should it be totally solid wood or a laminate variety?     If you choose to go with the latter, you’ll have to answer another important question.     What kind of wood edge banding do you want?     For many people who are new to buying residence hall furniture, that’s going to elicit some questioning faces.     What’s edge banding? Good question.     Or, if you’re a veteran, you already know how painful the wrong edge banding choice can be. That is to say, peeling, ongoing maintenance, and mounting work orders.     What Is Edge Banding?     So let’s start at the beginning. What is edge banding?     It’s actually kind of simple, and the video below will help you understand it even better, but this is a simple overview to get you started.     Here’s the basic non-technical idea.     Plywood, particle board, and other manufactured wood cores like MDF have rough, unfinished, unprotected, and generally unsightly edges.     To account for that, some clever folks developed technologies that allow you to glue different bands of glossy finished material to those rough edges to match the tops and sides.     Those narrow bands or strips are called edging tape, and they range in thickness from 0.018-inch to 5mm thick and in 250 ft rolls.     The thicker edging is used in high traffic and commercial environments because it provides greater resilience and impact resistance. For example, the military requires a thicker ?” solid wood edge banding for maximum impact resistance.     And edge banders are the industrial grade machines that apply the edging tape to the raw edges of the wood panels with a hot-melt adhesive or glue.     The Purpose of Edge Banding     Edge banding serves both functional and aesthetic purposes.     Functionally, edge bands perform some key duties for your furniture. First, it keeps moisture out serving as a de facto seal on the edge of the core material. Second, edge banding improves durability and resilience by providing impact resistance. If you’re using solid wood edging, it can also add to the overall strength of the furniture.     Aesthetically, edge banding covers up unsightly rough edges and creates a glossy finish to match your tops and sides. You can also create radial edges to soften sharp angles.     What Is Edge Banding Made From?     What are the edging tapes made from? There are different materials, and we’ll just focus on a few here.     1. PVC is the most popular material for edge banding. Pros: It’s inexpensive, durable, and boasts a long life. It doesn’t require any finishing process. It’s also easy, albeit tedious, to repair. Cons: You can’t recycle it. It doesn’t biodegrade. Once it’s blemished, you can’t refinish it. (NB: ABS—Acrylonitrile Butadiene Styrene—is an eco friendly alternative to PVC because it’s both recyclable and safe to incinerate.)     When it comes to PVC, we recommend 3mm edging in general because it goes on cleaner, quicker, and with better adhesion. Another advantage is that you get a graceful radius and a nice soft-looking finish. In general, we avoid .5mm edging because the corners tend to be too sharp.     2. Solid Wood is still a favorite in many woodworking camps. It’s durable, recyclable, easy to fix and refinish, strong, stiff, and economical. Benefits: is more resistant to chipping than veneer edge tape. Solid wood glues are more reliable and less prone to peeling than veneer and PVC. It provides additional dimensional support to plywood and mdf. Climate neutral manufacturing. Cons: Difficult to use for curves.     When it comes to solid wood we recommend 9.5mm on case good tops.     As we explain below, at DCI, we believe the best way to apply wood edge banding is “internally” with a HPL top. Why? Because in our experience, it’s incredibly durable and never requires additional service.     Wood Veneer     3. Wood Veneer, including reconstituted veneer is another common edge banding material. It’s made from thin slices of wood—typically oak, maple, ash, walnut, birch, and mahogany—that are joined together in a roll using finger jointing. It usually features a heat-sensitive glue backing.     Pros: It’s attractive, durable, and strong. It provides a clean solid-wood look, and it’s pre-sanded to easily absorb stains and finishes to seamlessly match your wood. Cons: It’s not heat resistant. Avoid putting it near a heater. It doesn’t do well in high-use environments.

Fecha de Publicación: 03-09-21

UNDERSTANDING AUDIO AND VIDEO WIRE AND CABLE

Descripción: WHAT IS A CONDUCTOR?     An Electrical conductor is an element (remember the periodic table in chemistry?) which conducts electricity, as opposed to an insulator, which does not, or a semiconductor which allows some electricity to pass. There are also alloys that have different electrical characteristics, and platings or other element to element contacts such as in connectors which also have electrical characteristics as well as chemical characteristics in their applications. Simply stated - it is not just a matter of connect metal to metal and you have a good connection. The best connectivity designs take into account the source connector materials, the receiving device connector materials, the audio video wire connector materials, the conductor materials and the electrical and chemical ways in which they interact with one another.     MEET THE CONDUCTORS - SILVER, COPPER, GOLD, TIN, NICKEL, STEEL     1. Silver is the best conductor, with a very slight edge over copper. Silver also has the benefit of having oxidation that conducts as well as unoxidized silver.     2. Copper is the next best conductor, with about 1.05 times the resistance of silver, and due to its lower cost is the most commonly used conductor for audio and video cables. Unfortunately copper oxidation is a semi conductor and should be avoided because of the "skin effect" which causes high frequencies to use the outside of the conductor at high frequencies. If the outside of the conductor is oxidized, the performance at very high frequencies will suffer. Note: This is does not have any significant effect in the audio frequency range. (For more on Skin effect see the Article Library at Audioholics)     3. Gold has about 1.4 times the resistance of copper and does not oxidize making it a popular plating for audio and video connectors.     4. Tin is a poor conductor, with about 8.5 times the resistance of copper, but has good resistance to oxidation and the oxide has good conductivity. Tin is quite often used to protect copper from corrosion.     5. Nickel has about 4.5 times the resistance of copper, good resistance to oxidization and good oxide conductivity. Nickel is a very common connector plating.     6. Steel has about 7 times the resistance of copper, lousy resistance to oxidization and lousy oxide conductivity. Steel is generally used only on high frequency cables plated with copper that need very high strength.     TYPES OF WIRING AND THE "BIRTH" OF THE AUDIO/VIDEO CABLE     Discreet wiring - Discreet wiring is where separate conductors, indluding speaker wires, are run in some fashion (wires or circuit board traces) to the circuit components or input/output connections to which they need to go to. In some circuits, especially non signal related connections the path or interaction of these types of wires to one another is not particularly important as long as they are separated from one another to a reasonable extent. The closer they get, the more likely they are to possibly interact. This all goes out the window when a signal or "change" (whether they are due to ac power wire, analog signals or digital signals - basically any type of current or voltage change) becomes a part of the mix.     Example: Two wires are close together while another two wires are farther apart. The closer wires act more like a capacitor (have more capacitance) than the second two wires. If the circuit is in a quiescent state - "at rest" (no changes are going on) , there is potential energy storage due to capacitance, but without change, it has no effect on any signal, since there is no change. If you then create a change, or signal wire that causes electrical current flow, the two sets of wires may then have an effect on those changes, due to capacitance, inductance, etc, and the changes created may be different depending on the frequency of the signal involved and the characteristics of the wires and the overall circuit.     Example: A wire that has current flowing through it has a magnetic field. Two wires close together with current flowing through them both have magnetic fields. The two magnetic Fields will interact with one another if close enough and this interaction will effect the currents flowing through the wires more or less, depending on the rate of the change. If the wires are "send and return" signal wires the current flow will be opposite. If the current flow is opposite, the magnetic fields are in opposite directions.     Electromagnetic noise acting on these opposite fields are canceled out (dependent on the frequency and distance between conductors) - thus is born the improvement for signal transmission called the cable.     TYPES OF SHIELDING AND PROPERTIES:     Braids, Served Shields and Foil - A braid is as it sounds a "braiding" of conductor material that in this case surrounds the inner insulator and center conductor. Served shields are a layer of individual strands of wire which are laid one next to the other with a spiraling twist around the insulator and conductor. A foil is pretty much what it sounds like - an extremely thin, solid (not stranded) foil like shield surrounding the insulation and inner conductor and often inside and/or outside of another shield.     Coverage and frequency - A served shield does quite nicely for coverage at lower frequencies, at least until flexed, which will make them more noise susceptible. A braid is great for coverage and dual braids reach up to around 95% coverage. The tighter the braid the smaller the "holes" and the higher the frequencies need to be to penetrate the shield. Obviously, dual braids would end up with smaller holes, and a foil braid can provide up to 100% coverage. So why not just use foil? Isn't 100% perfect? No, because foils just don't give a stable, and consistent impedance over the length of the cable, durability, or consistency when flexed. Many extremely cheap audio and video cables are made with a simple foil shield - they break very easily and generally perform very poorly.     Triboelectric effects, microphonic effects (handling noise) - Flexing, twisting, or transient impacts on cables with the floor, etc, while in use will cause "snaps", "crackles", "pops" and other noises in the signal due to rapid changes of capacitance between conductors. This is generally regarded an audio problem, normally effecting microphone cords and guitar cords. Served shields are ideal for reducing triboelectric effects. The geometry is good at resisting large capacitive changes while flexed or impacted. Braids are generally not nearly as good as served shields for this, again due to their design. Movement, and compression will cause noise. Foils are the worst for this - they are easily deformed causing large changes in capacitance and large "pops" coming from PA systems. Any live sound PA system engineer or studio engineer Needs to be deeply knowledgeable about these effects and how to avoid them at any cost.     *Note - Steel Coat Hangers as Cable      While the typical crazies on forums suggest that coat hangers will operate just fine as an audio cable (and poorly designed tests concur) there are definitive reasons why it is not a remotely good choice. First of all, Steel is a very poor conductor with over 7 times the resistance of copper wire. That means lots of wasted power supply wire. Second, steel oxidizes easily and the oxidization is a poor conductor. Third, steel is rather hard to make into a twisted pair, allowing for EMI and RFI resistance. Without making the steel into a twisted pair, Noise and Hum may become a larger than desired portion of the sound!

Fecha de Publicación: 03-09-21

Applications for laser cleaning

Descripción: From manufacturing plants and medical labs to the automotive, aviation, and steel fabrication industries, the laser is becoming the most preferred method for surface cleaning of materials.     Although the use of lasers in laser cutting machine, drilling, and laser welding machine applications is well known, its current adaptation in industrial cleaning applications is relatively new and unexplored.     This current application of lasers came as a result of the need for a nonhazardous, nonabrasive cleaning method that could be used as a substitute in applications where chemical, manual, and abrasive blasting methods were formerly used.     Benefits of using lasers in cleaning applications     Key problems presented by conventional cleaning methods include negative environmental impact and wear on the substrate. Abrasive blasting systems created significant amounts of waste and damaged delicate surfaces, while the use of chemical solvents resulted in potentially hazardous vapors and liquid waste products.     This led to the adaptation of laser technology in surface cleaning applications. Due to its many benefits, laser cleaning machine is now the most effective method of removing unwanted matter from the surface of materials.     Currently, there is a wide array of pulsed laser cleaning and de-coating systems used in various applications ranging from removing vulcanizing residue from tire molds and engraving surfaces by ablation to stripping insulation from conductors and de-coating paint from delicate surfaces.     Some of the many benefits of using lasers in surface cleaning applications include:     Automated and nonrandom cleaning method     Reduced amount of waste products     Increased safety     No need for chemicals or blasting media     Nonabrasive and noncontact cleaning process     Laser cleaning applications     Surface profiling and rust removal in steel fabrication. Portable laser cleaning machine is also an effective and efficient method for removing rust and scale from metallic materials. Rust and scale are contaminants that form on metal surfaces as a result of natural or artificial processes. When metals are exposed to moisture, they react with water to form ferrous oxides, resulting in rust. This rust degrades the quality of the metal, making it unsuitable for use in various applications.     On the other hand, scales form on metal surfaces as a result of heat treatment processes and its oxide discolors the metal surface, preventing any subsequent finishing operations.     Removing these unwanted surface deposits requires the execution of descaling processes to provide smooth surfaces for prefinishing and finishing processes such as electroplating.     Conventional rust removal and descaling operations involve the use of physical methods such as blasting, polishing, scraping devices, extra blows, and wire brushes. Chemical methods such as alkali descaling and acid descaling (pickling) can also be used for scale removal. However, these methods are very abrasive and result in environmental pollution and damage to the substrate metal.     To avoid these disadvantages, laser cleaning has become the preferred method for rust removal and descaling operations. The rust/scale is removed by directing a laser beam with high peak power and repetition rates on the rusted layer.     The industrial laser cleaning machine must be fired in short pulses to avoid damage to the substrate being worked on. The rust rapidly absorbs the energy of the laser beam, resulting in increased temperature levels. Once the temperature is sufficiently high, the rust melts and eventually vaporizes.     Using pulsed fiber lasers is the preferred option since it provides greater control over power, wavelength, and pulse duration, allowing the rust/ scale to vaporize without any damage to the underlying material.     The laser cleaning process can also be applied to surface profiling. Before protective coatings can be applied to fabricated steel parts for preservation and protection from corrosive action, their surfaces must be clean and free from all contaminants.     Surface profiling/preparationentails the removal of all contaminants from the surface of steel parts in preparation for protective coating applications. These contaminants include oil, grease, scale, hydrates and oxide layers, shop-primer, etc. For any subsequent processes, the bars, wires, and profiles must also be free from these contaminants.     Since fiber laser cleaning uses a nonabrasive, noncontact approach without the involvement of solvents, chemicals, or abrasive media, it is ideal for surface profiling and rust/scale removal. The cleaning process can be conducted on a small or large scale and can be automated. Precision laser cleaning machine is an environmentally friendly and cost-effective way to remove rust and prepare the surfaces of rolled steel products and fabricated steel parts for protective coating.     Anode assembly cleaning. The aluminum smelting industry uses carbon blocks as "sacrificial" anodes in the production of primary aluminum. The quality of the anode has an impact on the environmental, economic, and technological aspects of aluminum production. A small percentage of cell power is devoted to overcoming the electrical resistance of prebaked anode.     The presence of dirt and other contaminants will increase the anode's electrical resistance, resulting in the consumption of more cell power. The presence of contaminants also reduces the lifespan of the anode by increasing its rate of consumption during the smelting process. From the standpoint of efficiency, it is necessary to clean and remove all surface contaminants from anode assemblies before they are used in aluminum smelting operations.     In addition, anode assemblies are valuable tools that can be reused, but only after executing a thorough and careful treatment of its main components—under specific conditions.     Laser cleaning meets the specific conditions under which anode assemblies can be treated for reuse. It can be used in the following applications:     Removal of residue from carbon butts     Cleaning of cathode bars     Removal of contaminants and dirt from thimbles and stub rods     Adhesive bonding preparation for metals. To increase process stability, surface adhesion, and better seam quality, the surface of the metallic materials to be joined must be prepared before the application of welding and other joining techniques.     Without the necessary groundwork, joints and seams become susceptible to degradation, increased wear, and catastrophic failure. Laser cleaning can be used to prepare surfaces before they are joined, resulting in excellent bond strength quality for improved corrosion resistance and durability.     Laser cleaning is suitable for adhesive bonding preparation since it removes oxides and other contaminants such as grease and oxides that reduce the strength of adhesive bonds. It is particularly suitable for applications involving curved or flat surfaces or parts with certain limitations for highly complex 3D geometries.     One of the major benefits of laser cleaning is the ability to fine-tune its power and wavelength for precise modification of metals such as magnesium and aluminum to be used for microstructuring purposes. It also endows materials with very high resistance to corrosive elements, ensuring stable, long-lasting adhesive bonding.     In recent times, there is an increased use of adhesive bonds in structural design applications in place of conventional joining techniques such as riveting and welding. This is attributed to the many advantages of adhesive bonding over conventional techniques.     These advantages include uniform stress distribution, corrosion reduction, structure lightening, vibration attenuation, and acoustic insulation. However, these benefits can only be achieved if the surfaces to be bonded are prepared, degreased and carefully cleaned.     Laser cleaning is ideal for such applications since it carefully removes oils, rust, protective coatings and other contaminants resulting from shipping without harm to the underlying substrate.     Pretreatment for brazing and welding. Laser cleaning has also proven effective in pretreatment applications for welding and brazing. Before aluminum and steel materials are used for welding purposes in shipbuilding, precision tool manufacturing, automotive, and other related industries, their surfaces must first be prepared.     Laser weld preparation is one of the many applications of laser cleaning and handheld laser welding machine and helps to remove ferrous and nonferrous metals, lubricants, and other contaminants from metal and aluminum surfaces in preparation for high-quality welds. It also ensures smooth and pore-free brazed seams.     When used in pretreatment processes for welding and brazing, laser cleaning does the following:     Thorough removal of shop-primer, hydrates, and oxide layers     De-greasing and de-oiling     Apart from welding and brazing preparation, lasers can also be used to remove weld residues such as residual flux and oxide materials as well as thermal stains from finished weld joints. This cleaning method is particularly beneficial for stainless steel parts since laser light suspends grain boundaries, ensuring that weld seams are passivated—thus increasing corrosion resistance.     The benefits of using laser cleaning in welding and laser marking machine and brazing pretreatment applications include:     Adjustable wavelengths and power for precise treatment of joining surfaces over a wide range of material thicknesses     No damage to the underlying substrate—that is, the galvanized layers of sheet steel     Partial decoating. Laser cleaning is particularly effective in applications that require the partial removal of paint or coatings from finished surfaces. It can be used on virtually all surface types, whether chemically anodized, oxidized, or organic. Laser cleaning can be used to de-coat solar panels and remove paint in the automotive and aerospace industries while maintaining the integrity of the primer substance.     In de-coating applications, fiber lasers are the preferred option. They obviate the need for masking by precisely removing the layer of coating in the specified area, thus eliminating some of the challenges inherent in partial de-coating applications. Lasers can be used in:     Precise treatment for functional and design surfaces     Creating Faraday cages and continuity contacts for the aerospace industry     Partial removal of paint for electromagnetic compatibility     Produce bond points for wire connections     Strip coating in the electronics and automobile industry     Laser cleaning is highly effective in situations where critical weld seams on painted structures/parts must be de-coated for inspection purposes. The laser removes the coatings without the need for hand or power tools, abrasives, or chemicals that can hide the problem areas and cause further damage to the surface.     Selective paint removal. Selective paint removal represents one of the many applications of laser cleaning. In the automobile and aerospace industry, it is sometimes necessary to remove the top layer of paint while maintaining the primer. This is often the case when the top weathered coatings on vehicles need to be thoroughly removed before the application of a new paint finish.     Since the top layer of paint is physically and chemically different from the underlying primer, the power and frequency of the laser can be set to a frequency that only removes the top layer of paint.     The primer remains intact since the laser has no mechanical, chemical or thermal effect on it. This ensures the maintenance of the primer's corrosion resistance ability. When bare metal-to-metal contact is required for electrical continuity between parts, the laser cleaning process is preferred since it saves time and materials while improving the quality of the finished surfaces.

Fecha de Publicación: 03-09-21

Top Benefits Of Herbal Extracts

Descripción: The health benefits of plant-based supplements have been known for centuries. In fact, the use of herbal medicines is said to date as far back as 60,000 years  – long before the advent of modern medicine.     Used in cuisines all over the world, some of the most well-known herbs and fruits are blessed with natural herbal extract compounds that are advantageous to human wellbeing. Specifically, these are packed with bioactive compounds, such as polyphenols, which are linked to antioxidant activity in the human body.     The question is, then, what’s the point of liquid herbal extracts – like Comvita’s Olive Leaf Extract which is known for its antioxidant effects?     While eating fresh fruits and vegetables and adding herbs to your food are an important part of a healthy, well-rounded diet, here are some of the top benefits of supplementing your diet with liquid extracts.     POTENCY     Plants in their raw form don’t contain the same concentration of beneficial antioxidant compounds as you’ll find in liquid herbal extract – in fact, it’s vastly different..     So, consuming liquid herbal extract in addition to a healthy balanced diet is a convenient way to give your a top up of beneficial antioxidants without trying to eat impossible amounts of herbs, fruits and vegetables.     EASY TO CONSUME AND VERSATILE     It’s important to maintain a healthy diet, but it can be tricky to ensure you’re incorporating all of nature’s most precious compounds into an everyday diet.     Olive Leaf Extract can be taken alongside your daily meals to get the benefit of their nutrients and antioxidant compounds. For example, you could add the recommended amount of olive leaf extract to drinks such as water, juice and tea.     For a long time, extraction has long been a popular method for getting the beneficial nutrients and compounds out of plants and herbs. For the most part, this has traditionally been done using hot water to make a ‘tea’.     But while extraction methods have continued to evolve, Comvita has remained dedicated to preserving freshness and natural processes. Comvita Olive Leaf Extract is not extracted with alcohol and uses only freshly picked olive leaves in the extraction process which takes place onsite at our Queensland olive tree grove. You can find out more about our Olive Leaf Extract here.     Cosmetics are products designed to cleanse, protect and change the appearance of external parts of our bodies, like food additives in food industry. The key cosmetic ingredients present in most cosmetics include water, emulsifiers, preservatives, thickeners, moisturisers, colours and fragrances. Ingredients can be naturally occurring or artificial, but any potential impact on our health depends mainly on the chemical compounds they are made of. The doses of potentially dangerous chemicals found in cosmetics are considered too small to pose a risk to human health.     Natural products, such as natural fruit and vegerable powder, used to be sold primarily in health food stores and farmers markets with labels decorated with pictures of leaves. It was a very specific niche and not taken seriously by the beauty industry. But now sleek new brands positioning themselves as “cleaner” alternatives to the mainstream are exploding.     Daniela Ciocan — the marketing director at Cosmoprof North America, an entity that hosts a large expo where brands can display their wares in hopes of landing retail placement — says that thanks to retailer and customer demand, this year the organization doubled the amount of space it dedicated to new “clean” brands at the 2017 convention.     In the past 12 months, so-called natural brands like Tata Harper and Jessica Alba’s Honest Company products with natural color have made up about a quarter of all higher-end skin care sales, according to the NPD Group. The category is growing at a faster rate than last year.     “We’re absolutely inundated,” says Annie Jackson, a co-founder of Credo, which was dubbed the “Sephora of clean beauty” when it launched in 2015. It currently has eight stores in the US and a robust online business, where it sells about 115 brands. Credo receives about 200 new products a month from brands hoping to sell there.     And it has a competitor. Follain, which opened before Credo in 2013 as a local shop in Boston, is growing rapidly. It currently has five stores, will open two more in October and expects to have 10 by the end of 2019. Its growth rate is up more than 200 percent in 2018.     In the meantime, customer demand means mainstream companies and retailers are giving more lip service to the concept of clean beauty. In 2017, Target bumped up its natural beauty offerings. CVS announced it was removing parabens and other ingredients from 600 of its house-branded products by the end of 2019. Brands regularly remove parabens and sulfates and the like, sometimes quietly and sometimes with great fanfare.     Sephora launched its “Clean at Sephora” initiative in May, citing in-house research that revealed that 54 percent of its skin care shoppers think it’s important that their products “have a point of view on clean” and looking to shop brands that are “grounded in a ‘free of’ ingredient perspective,” according to Cindy Deily, the senior director of skin care merchandising at Sephora, though she did not say free of what. Sephora received some criticism that its clean standards weren’t as rigorous as they could be, but Deily says the “no” list is still evolving.

Fecha de Publicación: 03-09-21

Balloon Inflator Pumps: The Definitive Guide to Choosing and Using them.

Descripción: This article will present the definitive guide to choosing and using balloon inflators as you prepare to create your next masterpiece balloon decoration.     Inflating balloons can be a tiresome activity if you are inflating more than two balloons with air from your lungs. Fortunately, manual balloon pumps and electric balloon inflators make this process a breeze.     The Old Way of Inflating Balloons     So you are having an event, maybe a party and you want to decorate using balloons. As you consider inflating tens of balloons with your lungs, you may be dreading the consequences: sore cheeks, painful jaws, tired arms, aching lungs, and chest, just to name a few. The old method required time, people, patience, and determination.     The solution to the problem of inflation     A solution to your problem is here. Thankfully it is the dawn of a new era; balloon inflators have now become extraordinarily cost-effective and accessible to the DIY person or balloon decorator. These devices exponentially reduce the time and effort required to inflate a large number of balloons. It takes approximately 10 pumps on a double-action balloon pump to fully inflate a balloon and about 3 seconds to do the same using an electric balloon pump. So now, you are free to create your balloon arches, garlands, stands, centerpieces, and backdrops for your special events.     What is a Balloon Pump?     A balloon pump or inflator is a device that makes filling balloons with air faster and more efficient. Balloon Pumps are either manually or electric balloon pump. A balloon pump is designed with a special nozzle that can securely hold the balloon in place during inflation.     Types of Balloon Pumps     There are various types of balloon pumps, they are primarily separated into manual and electrically operated pumps:     Manual Hand-operated Balloon Pump/Inflator     A manual hand inflator is a cylindrical device with a handle connected to a shaft. The shaft is attached to a disc that extends to the edges of the tubular body of the pump.  The pump is operated by using the handle to force air through the connected nozzle. There are two additional categories of manual inflators:     Single Actions Balloon Pump     A single-action balloon inflator will only push air through the nozzle into the balloon on the forward stroke. The reverse stroke will refill the pump with air. This is great for a small number of balloons.     Dual or Double Action Balloon Pump     A Double action manual balloon pump can inflate a balloon on both the forward and reverse stroke. Making the process twice as efficient for the same amount of energy you put out. This is great for inflating an average number of balloons for a small event.     Electric Balloon Pump(AC air pump, DC air pump)     An electrically operated balloon pump uses a motorized pump to quickly send high volumes of air through its nozzle to fill the balloons. They deliver significantly more air in a shorter time when compared to a manual pump with practically no effort. Many are even outfitted with as many as four nozzles to support the inflation of multiple balloons at once. This is great for a large number of balloons and a big event.     When choosing between manual and electric balloon pumps, you have to take several things into consideration.     How much are you willing to spend?     An electric balloon pump can be more than 5 times the cost of a manual inflator. That price does not include the professional balloon pumps that can pump all ballons to the same size, adjust pressure settings, or the ones that come with a portable battery. Those can go upwards of 20 times the cost of a manual balloon pump.     How Many Balloons do you need to inflate?     If your balloon arrangement has more than 200 balloons, it may make sense to get an electric balloon pump. At this many balloons, it becomes a physical workout to use a manual balloon pump. However, if you have the time and the energy, you can consider it your arm workout for the day. You can even share the task between more than one person to lighten the effort.     Is this a one-off activity?     If you are planning to create large, multi-hundred balloon arrangements regularly. It will probably make more sense to invest in a reliable electric balloon pump. Not only will it require less time and effort, but most manual ballon pumps are made of plastic; frequent usage can cause the pump to become brittle, and the handle tends to break from overuse. This can be mitigated if you have multiple hand pumps, but for efficiency, an electric pump is more advantageous.     Will you have access to an electrical outlet.     For outdoor balloon decoration setups that are far away from an electrical outlet, a manual hand pump is the most ideal tool for the job. You can pull it out on the spot and inflate as many balloons as you need without going back and forth to an electrical outlet. Even though it is the most convenient way to inflate balloons for outdoor use, it is by no means the only way.     You can use large garbage bags and inflate your balloons ahead of time then transport them to your outdoor location. You can invest in a very long extension cord that will provide the reach you require. If you have a vehicle nearby, you can use an electrical inverter to power your balloon pump from your vehicle. You can also utilize the long extension cord there as well. The final method is to invest in a battery-powered electric pump. Battery-powered electric inflators are rechargeable and portable and can cost a pretty penny for these extra features. However, sometimes the investment may be worth it if you need the advantage of portability and the power and ease of an electric pump.     Is your environment noise friendly?     Electric balloon inflators are noisy. This is due to the powerful motor it uses to inflate balloons quickly and at high pressure.  If you are setting up a balloon arch at daycare during nap time, you might want to opt for your manual balloon hand inflators.     How fast do you want to work?     In the time it takes to inflate one balloon using a double-action balloon pump, you can inflate 4 using a two-valve electric balloon inflator. Electrical inflators are fast and powerful. If you need speed and power, electric battery air pumps are the right choice.     How many people are working along with you?     If you have multiple people working on your balloon decoration project, you can choose between a electric or a hand air pump. Various people using their own hand-operated balloon inflators can work out well in terms of a balance for the cost and speed you may need. This is the least expensive and most efficient use of a manual balloon inflator.     Electric rechargeable air pumps can also use multiple people at the same time. Depending on your pump type, electric balloon pumps can have as many as 4 active valves used to inflate balloons simultaneously. This will increase your efficiency.     How strong are you?     Manual balloon inflators require an average amount of physical strength to inflate a large number of balloons. A good quality hand-held balloon pump will be well lubricated. It should not provide much friction when pumping air into the balloons. However, if this is not the case, or if the lubrication has somehow dried up, it will take added energy to inflate balloons with a manual pump.     Children should generally have little to no problem using a manual balloon inflator if it is well-lubricated. An electric balloon pump takes limited effort more than the strength to hold the balloon in place as it is inflated.     Multipurpose usage     Due to the design, portability and lightweight of the hand balloon pump, it can be easily used to inflate other inflatables such as pool float toys, exercise balls, inflatable toys like the Rody Horse, and even small sleeping mattresses. Manual Balloon pumps can also be used to blow dust from hard-to-reach crevices instead of purchasing a can of compressed air.     Helium Balloon Inflator     Helium balloons do not require a balloon pump since helium is usually stored in a cylinder in compressed form. Balloons are then simply inflated by opening a valve attached to the cylinder of compressed helium.     Where to buy     The cost of balloon inflators has reduced over the past couple of years. You can get professional level pumps, such as high pressure air pump, for a fraction of the price.     Inflatable paddle boards are typically quick and easy to inflate, and many of them come with a manual pump that can inflate a SUP in about 10 minutes. However, younger or much older SUPers might find inflating them difficult, while others just want to spare themselves from the strain and sweat that comes with manual pumping. Alternatively, if you’re heading to the lake to get some yoga or meditation in, having to put so much time and work in inflating a SUP electric pump doesn’t exactly put you in a peaceful mindset.     That’s why our number one recommended accessory for all inflatable paddle boarders is an electric pump. An electric pump can inflate your paddleboard just as fast as a manual pump, but without the effort of having to do it yourself. Electric pumps can also help finish deflating your iSUP for you, making sure all the air is out and it can be packed up super tight at the end of the day. Some electric pumps are also smaller and weigh about the same asn traditional manual pumps, making them easier to pack and carry as well. Some electric pumps even come with an integrated or portable battery, meaning you don’t even have to be near a car to use them.     An electric pump is better than a manual pump in almost every way, with many of them available for less than $150. However, just like SUP pump, there are a ton of electric pumps to choose from.

Fecha de Publicación: 03-09-21

Understanding Metal Stamping

Descripción: Metal stamping is a cold-forming process that makes use of dies and stamping presses to transform sheet metal into different shapes. Pieces of flat sheet metal, typically referred to as blanks, is fed into a sheet metal stamping press that uses a tool and die surface to form the metal into a new shape. Production facilities and metal fabricators offering stamping services will place the material to be stamped between die sections, where the use of pressure will shape and shear the material into the desired final shape for the product or component.     This article describes the metal stamping process and steps, presents the types of stamping presses typically employed, looks at the advantages of stamping parts compared to other fabrication processes, and explains the different types of stamping operations and their applications.     Basic Concepts of Metal Stamping     Metal stamping, also referred to as pressing, is a low-cost high-speed manufacturing process that can produce a high volume of identical metal components. Stamping operations are suitable for both short or long production runs, and be conducted with other metal forming operations, and may consist of one or more of a series of more specific processes or techniques, such as:     1. Punching     2. Blanking     3. Embossing     4. Coining     5. Bending     6. Flanging     Punching and blanking refer to the use of a die to cut the material into specific forms, such as pole line hardware. In punching operations, a scrap piece of material is removed as the punch enters the die, effectively leaving a hole in the workpiece. Blanking, on the other hand, removes a workpiece from the primary material, making that removed component the desired workpiece or blank.     Embossing is a process for creating either a raised or recessed design in sheet metal, by pressing the raw blank against a die that contains the desired shape, or by passing the material blank through a roller die.     Coining is a bending technique wherein the workpiece is stamped while placed between a die and the punch or press, such as sheet metal fabrication. This action causes the punch tip to penetrate the metal and results in accurate, repeatable bends. The deep penetration also relieves internal stresses in the metal workpiece, resulting in no spring back effects.     Bending refers to the general technique of forming metal into desired shapes such as L, U, or V-shaped profiles. The bending process for metal results in a plastic deformation which stresses above the yield point but below the tensile strength. Bending typically occurs around a single axis.     Flanging is a process of introducing a flare or flange onto a metal workpiece through the use of dies, presses, or specialized flanging machinery.     Metal stamping machines may do more than just stamping; they can cast, punch, cut and shape metal sheets. Machines can be programmed or computer numerically controlled (CNC) to offer high precision and repeatability for each stamped piece, and this technology is widely used in furniture hardware. Electrical discharge machining (EDM) and computer-aided design (CAD) programs ensure accuracy. Various tooling machines for the dies used in the stampings are available. Progressive, forming, compound, and carbide tooling perform specific stamping needs. Progressive dies can be used to create multiple pieces on a single piece simultaneously.     Types of Stamping Operations     Progressive die stamping     Progressive die stamping uses a sequence of stamping stations. A metal coil is fed into a reciprocating stamping press with progressive stamping dies. The die moves with the press, and when the press moves down the die closes to stamp the metal and form the part. When the press moves up, the metal moves horizontally along to the next station. These movements must be precisely aligned as the part is still connected to the metal strip. The final station separates the newly-fabricated part from the rest of the metal. Progressive die stamping is ideal for long runs, because the dies last a long time without becoming damaged, and the process is highly repeatable. Each step in the process performs a different cut, bend, or punching operation on the metal, thus gradually achieving the desired end-product shape and design. It is also a faster process with a limited amount of wasted scrap.        Transfer Die Stamping     Transfer die stamping is similar to progressive die stamping, but the part is separated from the metal trip early on in the process and is transferred from one stamping station to the next by another mechanical transport system, such as a conveyor belt. This process is usually used on larger parts that may need to be transferred to different presses.     Four-Slide Stamping     Four-slide stamping is also called multi-slide or four-way stamping. This technique is best-suited for crafting complex components that have numerous bends or twists. It uses four sliding tools, instead of one vertical slide, to shape the workpiece through multiple deformations. Two slides, or rams, strike the workpiece horizontally to shape it, and no dies are used. Multi-slide stamping can also have more than four moving slides.     Four-slide stamping is a very versatile type of stamping, such as in electronics hardware, as different tools can be attached to each slide. It also has a relatively low cost, and production is fast.     Fine Blanking     Fine blanking, also known as fine-edge blanking, is valuable for providing high accuracy and smooth edges. Usually done on a hydraulic or mechanical press, or by a combination of the two, fine blanking operations consist of three distinct movements:     Clamping of the workpiece or work material in place     Performance of the blanking operation     Ejection of the finished part     Fine blanking presses operate at higher pressures than those used in conventional stamping operations, hence tools and machinery need to be designed with these higher operating pressures in mind.     The edges that are produced from fine blanking avoid fractures as produced with conventional tooling and surface flatness can exceed that available from other stamping methods. Since it is a cold extrusion technique, fine blanking is a single-step process, reducing the overall costs of fabrication.     Types of Stamping Presses     The three common types of stamping presses include mechanical, hydraulic, and mechanical servo technologies. Usually, presses are linked to an automatic feeder that sends sheet metal through the press either in coil or blank form.      Mechanical     Mechanical presses use a motor connected to a mechanical flywheel to transfer and store energy. Their punches can range in size from 5mm to 500mm, depending on the particular press. Mechanical pressing speed also varies, usually falling between the range of twenty and 1,500 strokes per minute, but they tend to be faster than hydraulic presses. These presses can be found in an array of sizes that stretch from twenty to 6,000 tons. They are well-suited for creating shallower and simpler parts from coils of sheet metal. They’re usually used for progressive and transfer stamping with large production runs.     Hydraulic     Hydraulic presses use pressurized hydraulic fluid to apply force to the material, such as in agricultural machinery parts. Hydraulic pistons displace fluid with a force level proportional to the diameter of the piston head, allowing for an advanced degree of control over the amount of pressure, and a more consistent pressure than a mechanical press. Additionally, they feature adjustable stroke and speed capabilities, and can typically deliver full power during any point in the stroke. These presses usually vary in size from twenty to 10,000 tons and offer stroke sizes from about 10mm to 800mm.     Hydraulic presses are usually used for smaller production runs to create more complicated and deeper stampings than mechanical presses, such as car spare parts. They allow for more flexibility because of the adjustable stroke length and controlled pressure.     Mechanical Servo     Mechanical servo presses use high capacity motors instead of flywheels. They are used to create more complicated stampings at a faster speed than hydraulic presses. The stroke, slide position and motion, and the speed are controlled and programmable. They are powered by either a link-assisted drive system or a direct drive system. These presses are the most expensive of the three types discussed.

Fecha de Publicación: 03-09-21

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