Standard mold bases

FIGURE 2.12 Exploded view of a standard mold base showing component parts. 

Production molds may also be made using a standard mold base which will accept, say, 12 identically sized cavity inserts. If the component to be produced is a small box with a lid and attachable cover, in, say, 12 different sizes, each cavity insert could contain the cavities for one size box and cover. The complete mold would produce 12 boxes and covers each cycle. If sales of any one size require greater quantities than are required for one or more of the other sizes, a second cavity insert could be made to fit into the mold base, enabling twice as many of the faster-selling size each cycle. For family molds to be successful, all parts should have approximately the same wall thickness so that molding cycles may be optimum for all sizes. 

Database. A collection of files, again usually organized around some conmion attribute or organized for a specific purpose. Continuing with this example, a number of data files that describe standard components can be further organized into a database that describes all the standard mold bases available from a particular manufacturer. 

Injection molds usually are constructed of steel for production runs, and the use of standard mold bases (steel parts which contain the cavities and cores) is recommended. A number of companies supply standard mold bases and parts. These can be less expensive and superior to those made by the mold maker due to high volume and specialized equipment. 

Prototype molds, because of their low volume requirements, can often be produced from less expensive materials. Brass, aluminum, or mild steel may be acceptable for low volumes and will machine much more rapidly than hardened steel. It may be acceptable to prepare cavity inserts that can be incorporated into standard mold base assemblies. 

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