Because of this similarity in the structural build-up of the majority of molds it is desirable that some form of standardization be adopted to permit the mold parts to be produced in quanity and thereby reduce manufacturing costs.Logically it is advantageous for the mold-maker to purchase a complete set of basic plastic mold parts at reasonable cost,rather than to be actively engaged on this relatively unimportant aspect of mold manufacture.
The two-plate mold is adopted as the standard plastic mold system by most manufactures because this particular mold construction is the most widely used design in industrial practice.The system comprise two mold plates （a cavity plate and a core plate) plus an ejector system,guide pillars,guide bushes,etc.
More complex structures such as three and four mold plate types can be achieved by using the two-part mold system concept as a structural base and adding (or subtracting) plates to suit.The majority of the conventional mold types can be obtained in this way.
It is important for the beginner to appreciate that the majority of mold designs can be broadly classified within one of these mold types.For example,a side-core type mold can be considered as a two-part mold with an additional side core assembly.
The designer may have to accept a compromise in mold size;the number of mold type and the range if size limited;for certain molds some modification to the mold unit is necessary to accommodate a specific feature.Considered overall,however,the advantage of using standard mold units outweight the disadvantages and for a large number of mold designs the standard mold system can be beneficially used by both the mold designer and mold-market.Nevertheless,on many occasions it is necessary to have a “made-to-measure” mold in order that a special feature may be incorporated or a specific coolant flow-way system adopted,or simply because a standard mold system of a suitable shape or size is not availble.
没有评论:
发表评论