Massimiliano Agnesi (
Sun, 29 Aug 1999 13:37:18 +0200

At 01.58 28/08/1999 -0400, you wrote:
>BTW are the molds for injection kits scuplted by hand or by computer
>controlled machine? If by hands, then scaling kits up and down the size
>ladder is no simple matter.

Usually, the end products of the research and costruction of a injection
model kit prototype (or master pattern) are resin casts of all the parts
that will make the real model kit. These pieces are usually two or four
times the size of the model kit because of the little parts.

The mold maker takes the resin casts and trascribes them into a steel mold
using a pantograph. A complex machine, the pantograph has a stylus on one
end with which the mold maker traces the contours of the resin model. The
machine then transfers the three-dimensional contours to a steel-cutting
bit on its other end, which engraves them into the metal mold. Different
sizes of bits are used, large at first to remove big chunks from the steel
mold, then smaller bits for the finer cuts.

Since the the resin models are larger than the actual molded parts will be,
proportional adjustments are made to the arms and pivots that carry the
motion from one end of the pantograph to the other, thereby enabling the
mold maker to reduce the model to the proper scale.
So, it is possible to scale MG kits (for example) down to 1/144.I guess if
the master pattern is big enough it's possible to make 1/100 MG kits from
the HGUC kits.

Once the mold maker finshes with the pantograph, the mold is hand finished.
The cavities are polished , and an engraver may be called in to hand detail
the intricate parts of the mold.

I hope this is clear enough.

Ciao, Max.

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