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Application of Silicone Rubber Keypad

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Common applications of silicone rubber keypads include remote controls for TV, video and HIFI units, electronic toys and games, and industrial control equipment. Industrial silicone rubber keypads such as ones produced by CTI Electronics Corporation are used in the medical, marine, or, military are typically sealed comply to specific industry standards such as NEMA or IP66 for protection against elements such as liquids or dust. Mobile phone handset manufacturers have, in recent years, been the main consumer of rubber keypads worldwide. Their involvement has led to advances in technology including the use of hard plastic key tops bonded to a rubber keypad and also the use of embossed Mylar layer to produce an enhanced tactile response. With the increased use of low current switching within automobiles, silicone rubber keypads are being used extensively as switch mechanisms for various function buttons such as window lifts and steering wheel mounted controls. With the availabilit
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Technology of Silicone Rubber Keypad

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The technology uses the compression molding properties of silicone rubber to create angled webbing around a  switch  center. On depression of the switch the webbing uniformly deforms to produce a tactile response. When pressure is removed from the switch the webbing returns to its neutral position with positive feedback. In order to make an electronic switch a carbon or gold pill is placed on the base of the switch center which contacts onto a printed circuit board when the web has been deformed. It is possible to vary the tactile response and travel of a key by changing the webbing design and/or the shore hardness of the silicone base material. Unusual key shapes can easily be accommodated as can key travel up to 3mm. Tactile forces can be as high as 500g depending on key size and shape. The snap ratio of a keypad determines the tactile feel experienced by the user. The recommended snap ratio for designers to maintain is 40%-60%; if dropped below 40% the keys will lose tactile fe
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Medical Grade Silicone Rubber

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Stockwell Elastomerics manufactures rubber gaskets and rubber components for medical device applications that are non-implant and in an area of the device where there is no exchange of blood or bodily fluids. Stockwell Elastomerics’ medical grade compounds are USP Class VI rated and are often sterilized using gamma, autoclave and ETO with minimal effect on the rubber compounds. Sample swatches for trial sterilizations and other validation testing are available. Common medical device applications include enclosure gaskets, housing gaskets, vibration or dampening pads. More often, Stockwell Elastomerics manufactures custom rubber parts for medical device OEMs to their engineering drawings. These custom medical components specify the type and durometer of FDA silicone rubber needed. These parts can be made from FDA grade liquid silicone rubber that can be injection molded or cut from FDA high consistency rubber (HCR). Both of Stockwell Elastomerics’ FDA silicone rubber types (LSR and H
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Types of Liquid Silicone Rubber

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Silicone rubbers are man-made polymer materials that have a wide range of industrial and manufacturing applications. The various types of silicone rubbers include room temperature vulcanize, liquid silicone, fluorosilicone and high-consistency rubber. In this post, we’ll provide information about liquid silicone rubber, including what it is and the types that are available for manufacturing purposes. WHAT IS LIQUID SILICONE RUBBER? Liquid silicone rubber (LSR) is classified as an elastomer, which means it possesses exceptional elasticity (ability to resume its normal shape after stretching). Key LSR attributes include hardness, tensile strength (resistance to break under tension) and compression set. Other LSR characteristics include excellent bacteria resistance and hydrophobicity, meaning that it acts as a water repellent. The two liquid silicone rubber types include food grade and medical grade. WHAT IS FOOD GRADE LSR? Food grade liquid silicone rubber is well-suited for
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Types of Injection Machines

Machines are classified primarily by the type of driving systems they use: hydraulic, mechanical, electrical, or hybrid Hydraulic Hydraulic presses have historically been the only option available to molders until Nissei Plastic Industrial Co., LTD introduced the first all-electric injection molding machine in 1983. Hydraulic machines, although not nearly as precise, are the predominant type in most of the world, with the exception of Japan. Mechanical Mechanical type machines use the toggle system for building up tonnage on the clamp side of the machine. Tonnage is required on all machines so that the clamp side of the machine does not open (i.e. tool half mounted on the platen) due to the injection pressure. If the tool half opens up it will create flash in the plastic product. Electric The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption and also addresses some of the environmental concerns surroundin
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Injection Pocess

With injection moulding, granular plastic is fed by a forced ram from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mould, allowing it to enter the mould cavity through a gate and runner system. The mould remains cold so the plastic solidifies almost as soon as the mould is filled. Injection moulding cycle The sequence of events during the injection mould of a plastic part is called the injection moulding cycle. The cycle begins when the mould closes, followed by the injection of the polymer into the mould cavity. Once the cavity is filled, a holding pressure is maintained to compensate for material shrinkage. In the next step, the screw turns, feeding the next shot to the front screw. This causes the screw to retract as the next shot is prepared. Once the part is sufficient
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Injection moulding

Injection moulding  is a manufacturing process for producing parts by injecting molten material into a mould. Injection moulding can be performed with a host of materials mainly including metals, (for which the process is called die-casting), glasses, elastomers, confections, and most commonly thermoplastic and thermosettingpolymers. Material for the part is fed into a heated barrel, mixed (Using a helical shaped screw), and injected (Forced) into a mould cavity, where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mould-maker (or toolmaker) from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers which do not melt during the injection mo
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