Re: zinc castings

From: Mnr. D de Beer (DDEBEER@ENG.TOFS.AC.ZA)
Date: Wed Jul 16 1997 - 10:40:56 EEST


I am not sure what you have in mind, but I would start looking for
someone active in "spincasting" (or centrifugal rubber mould
casting). We have our casting system in operation for just over a year
now, and can report very good products (replicas made in zink or other low melting-
point alloys - various products to suit different needs).

This method is somewhat unique compared to investment casting, as
your master (prototype) remains in tact for further use if necessary.
A further advantage is the price - a fraction of the price of other

Dependent on the number of replicas needed, there would be different

The traditional route would be to make an RTV mould for spincasting,
to produce a number of masters, which will bet used in a production mould
(vulcanised silicone mould). This opens up the door for a lot of
different RP technologies, as models made in almost any material
(wax, paper, epoxy, etc) can be used as a master pattern.

 Again, the planning of a master mould will depend on the part size and geometry.
(sometimes only one part will be used in a production mould) However, we have
 succeeded in making vulcanised moulds directly from SLA patterns - even though
the temperature exceeds the glass-transition temperature of the epoxy resin. Up to
now we had our SLA patterns made by a service bureau - thus limiting
 experimentation due to the cost thereof, but our SLA machine is being shipped at
this moment, and work in this area will continue.

I will keep you posted on our progress once our machine is

Deon de Beer
Faculty of Engineering
Technikon Free State
South Africa

This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:39:53 EEST