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In microelectronics, a dual in-line package is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads ; eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density chip carriers. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages.
In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold that contains a negative impression of the intended shape. The metal is poured into the mold through a hollow channel called a sprue. The metal and mold are then cooled, and the metal part is extracted. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods.
Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed, and injected 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 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 that do not melt during the injection moulding of some lower-temperature thermoplastics, can be used for some simple injection moulds.
Molding or moulding is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix. This itself may have been made using a pattern or model of the final object.
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand — known as casting sand — as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. In 2003, over 60% of all metal castings were produced via sand casting.
Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that permits it to be stretched into or onto a mold and cooled to a finished shape. Its simplified version is vacuum forming.
Vacuum forming is a simplified version of thermoforming, where a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mould, and forced against the mould by a vacuum. This process can be used to form plastic into permanent objects such as turnpike signs and protective covers. Normally draft angles are present in the design of the mould to ease removal of the formed plastic part from the mould.
A riser, also known as a feeder, is a reservoir built into a metal casting mold to prevent cavities due to shrinkage. Most metals are less dense as a liquid than as a solid so castings shrink upon cooling, which can leave a void at the last point to solidify. Risers prevent this by providing molten metal to the casting as it solidifies, so that the cavity forms in the riser and not the casting. Risers are not effective on materials that have a large freezing range, because directional solidification is not possible. They are also not needed for casting processes that utilized pressure to fill the mold cavity.
Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured; this process is known as compression molding method and in case of rubber it is also known as 'Vulcanisation'. The process employs thermosetting resins in a partially cured stage, either in the form of granules, putty-like masses, or preforms.
Blow molding is a manufacturing process for forming hollow plastic parts. It is also used for forming glass bottles or other hollow shapes.
Rotational molding involves a heated mold which is filled with a charge or shot weight of the material. It is then slowly rotated, causing the softened material to disperse and stick to the walls of the mold forming a hollow part. In order to form an even thickness throughout the part, the mold rotates at all times during the heating phase, and then continues to rotate during the cooling phase to avoid sagging or deformation. The process was applied to plastics in the 1950s but in the early years was little used because it was a slow process restricted to a small number of plastics. Over time, improvements in process control and developments with plastic powders have resulted in increased use.
A sprue is a large diameter vertical channel through which liquid material is introduced into a mold. It connects the pouring basin to the runner. In many cases it controls the flow of material into the mold. During casting or molding, the material in the sprue will solidify and need to be removed from the finished part. It is usually tapered downwards to minimize turbulence and formation of air bubbles.
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.
Lifecasting is the process of creating a three-dimensional copy of a living human body, through the use of molding and casting techniques. In rare cases lifecasting is also practiced on living animals. The most common lifecasts are 3D hand casting, casting of torsoes, pregnant bellies, faces, and genitalia and it is possible for an experienced lifecasting practitioner to copy any part of the body. Lifecasting is usually limited to a section of the body at a time, but full-body lifecasts are achievable too. Compared with other three-dimensional representations of humans, the standout feature of lifecasts is their high level of realism and detail. Lifecasts can replicate details as small as fingerprints and pores.
In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item. Combining the decoration process with the moulding process cuts the total cost, but can increase the manufacturing time. The technology was first developed by Owens-Illinois in cooperation with Procter & Gamble to supply pre-labelled bottles that could be filled on the product filling line. This was first applied to Head & Shoulders shampoo bottles.
Molded pulp or molded fiber is a packaging material, that is typically made from recycled paperboard and/or newsprint. It is used for protective packaging or for food service trays and beverage carriers. Other typical uses are end caps, trays, plates, bowls and clamshell containers.
In casting, a pattern is a replica of the object to be cast, used to form the sand mould cavity into which molten metal is poured during the casting process. Once the pattern has been used to form the sand mould cavity, the pattern is then removed, Molten metal is then poured into the sand mould cavity to produce the casting. The pattern is non consumable and can be reused to produce further sand moulds almost indefinitely.
Thin wall injection molding is a specialized form of conventional injection molding that focuses on mass-producing plastic parts that are thin and light so that material cost savings can be made and cycle times can be as short as possible. Shorter cycle times means higher productivity and lower costs per part.
Injection mold construction is the process of creating molds that are used to perform injection molding operations using an injection molding machine. These are generally used to produce plastic parts using a core and a cavity.
In plastics processing, dip molding is a process of shaping of plastics by moulding. The coating of components with PVC has many applications. Plastic dip moulding is a technique where metal parts are coated with a plastic vinyl material. It is used to protect and make the metal parts more resistant to scratches and abrasions.
References
- ↑ Crawford, Roy J. (2012-07-02). Practical Guide to Rotational Moulding, Second Edition. Smithers Rapra. p. 197. ISBN 978-1-84735-924-7.
- ↑ Frenkler, D.; Zawistowski, H. (2001). Hot Runners in Injection Moulds. iSmithers Rapra Publishing. ISBN 978-1-85957-483-6.