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Not your average carbon copy
Graphite permanent molding is a niche process used for building high-precision zinc-aluminum alloy parts. Assortment of parts molded in graphite permanent molds. Part being removed from graphite permanent mold showing attached runners and gates. Air-traffic control trackball housing is cast
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Molding a better plastic nut
reinforcing fibers at thread surfaces, which will cause friction and accelerate wear as the nut touches the leadscrew. The graph compares the break-in-wear curves of an injection-molded thread versus its machined counterpart. The performance of power-transmission nuts made from plastics can vary drastically
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Polyketones
, the range is 715 to 750° F. Mold temperatures from 355 to 420 °F are recommended for molding PEK, and 355 to 375°F for PEEK. Parts for high-temperature applications should be molded at the high end of the temperature range. Polyketones can be extruded to form sheet, cast-film, stock for machining
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Polyurethane
hydrolysis resistance, are easier to process, and cost less. Polyester-based foams have higher mechanical propertie.% better oil resistance, and more uniform Cill structure. Both types can be rayed, sP' molded, foamed in place, or furnished'ir sheets cut from slab stock - buns, 30 to-A in. high, to 80
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Coloring outside the lines
components molded from a number of different resins. These include a talc-filled polypropylene A pillar; a PC/ABS instrument-panel top cover, endcap, and fuse door; a high-crystalline polypropylene door panel; and door scuffs from an elastomeric thermoplastic polyolefin (TPO). One color-matching system
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MICRO:Product Technology News (Oct. '98, p.110)
and a pressure-relief valve. Clamped to the base with a large O-ring, the chamber has two quick-disconnect fittings for filling and purging. The chamber is made of low-outgassing transparent molded poly- urethane which blocks UV light at a rate of 2% below 250 nm. The filter in the nitrogen input line is rated
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Tips for no-melt machining
forming technique can indeed affect some physical properties. For example, injection-molded shapes show the greatest directionally dependent or anisotropic behavior. Extruded shapes are slightly anisotropic. Compression molded shapes, on the other hand, are isotropic. They show equal properties in all
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Plastics that perform
consideration that helps narrow the field of potential polymers is how the part will be fabricated: thermo-formed, injection molded, rotationally molded, machined, etc. Outside expertise can help. Material suppliers have specific processing data for their resins and may be able to share past product-design