Plastic Injection Molding Problem

I believe spark erosion is generally used.

Nishant - It is hard to know what and why you want to know. Maybe you want to know to improve yourselves and that is recommendable.

The following will describe roughly the process of making a die for producing coins.

The first step is to take a photo of the person and model the face in clay on a flat surface. This is really a job for an artist.

When this is done a negative mould is made in fine plaster.

The writing is then engraved in the plaster. (or it could be done with the original)

A positive copy is than made in a hard plastic on a big disk (say 5" diam)

The master is then placed on a turntable with the blank die on another turning at exactly the same speed.

A follower is then started at the centre of the master and move out wards slowly as it turns. The movement at the die is reduced to the correct size.

As the follower moves over the high and low places the tool at the die performs similar movements (inversed) and the contours are transfered to the die.

This process is very accurate. A tiny scratch on the master will show on the coin.