The purpose of the runner is to transport the melt from the sprue to the gates. There are three basic parameters for runner geometry: The cross-sectional shape The diameter The cavity layout The most efficient runner section is the full…
Cold Slug Well-This is designed to trap the cooler advancing front of the melt、thus permitting hotter melt to reach the cavities and gates. It usually has a snatch or pull pin or sucker pin underneath it to positively pull the…
All mold tools are expensive and easily prone to damage and corrosion if they are not maintained properly. In most injection molding shops, the mold storage area often houses a considerable capital investment, often running into millions of pounds. Before…
Mould Finishing-Nearly all cavity and punch forms require a Finish to be applied to them. This may be a Polished finish, a photo-etched finish or a plated finish. However, for some technical Components the surface finish is not important and…
Nitriding With this procedute the surface hardness() of steel can be increased by the formation of itom nitrides in the surface. The part is heated in a nitrogen-rich environment, usually a gas (ammonia) or a powder bath (the Tenifer process).…
Pretoughening The process of through-hardening steels and then finish machining them is time consuming and expensive; to avoid this, prehardened or pretoughened steels have been developed,the effect the steel is heat-treated in a similar way to normal through-hardened steels but…
Heat treating is a science in itself and should be left to specialists. One of the reasons the designer should stay with a minimum selection of tool steels is to avoid the many heat treatment specifications, which are usually different…
Bismuth-Tin Alloys These alloys are more commonly known as ‘Certo alloys, . When subject to shock loading they are quite brittle, but under constant loading conditions they exhibit some plasticity, Unusually the mechanical strength of these alloys increases with ageing.…
Zinc Alloys Zinc alloys have poor mechanical] strength and are unsuitable for production tooling. They are, however, often used for prototype tooling where only a relatively small number of parts are required for preproduction evaluation purposes. They have a low…
There is a noticeable trend towards the use of aluminum alloys for medium- to high- volume production in theUK, theUSAand increasingly in mainlandEurope. The principal advantages of this material are: It costs less than steel. It has good…