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#059 Fool Proof in Mold Design

Category : Technical Topics
October15, 2010

Literally, the meaning of "fool proof" has the nuance of "prevention of fooling".
In concrete terms, this refers to a construction or shape that prevents wrong assembly or disassembly by humans making an inadvertent mistake.

Taking the example of a mold, consider that there are two core pins A and B that are extremely alike. The position of incorporating in the main core is decided.
If, the mold was disassembled and maintenance work was done on it, there is naturally the possibility that the assembling positions A and B are reversed while assembling again the mold. It is not possible to eliminate completely inadvertent mistakes or misunderstanding even in the case of highly experienced persons.
In view of this, if the flange parts of the core pins are cut in different shapes and the assembly holes of the main core are also machined to those shapes, since it will only be possible to assemble the core pins A and B only at the correct positions irrespective of who does the assembling, there can be no wrong assembly.
These kinds of measures are called "fool proof" measures.

When there are parts that are likely to be assembled wrongly, or when there is a sequence for assembling, it is necessary to make fool proof designs so that there is no inadvertent mistake by the operator while assembling.
If a mistake is made in assembling a large sized mold or a mold for export, carrying out that work again can take a long time. In addition, by clamping a wrongly assembled mold can break the mold which can lead to a huge loss of money, etc.

For judging whether or not fool proof measures are required, it is very important to give training to mold designers not only about simple cost reduction considerations but also about making reviews regarding fool proof measures.

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