Re: Investment Casting

From: Martin Koch (mkoch@polymail.calpoly.edu)
Date: Fri Jun 19 1998 - 20:18:35 EEST


Scott Rackey wrote:
>
> Marshall,
>
> Actually, the term investment casting refers to the ceramic "investment"
> that serves as the mold.
>
> Some metals, such as titanium which reacts violently with oxygen at high
> temperatures, must be poured in vacuum. The crucible and the mold are
> placed in a large vacuum tank. The metal is heated through induction
> and then the entire tank is tilted to allow the metal to flow out of the
> crucible and into the mold.
>
> This should not be confused with the various vacuum forming techniques
> used with plastics.
>
> Hope this helps.
>
> -Scott Rackey
>
> Marshall Burns wrote:
> >
> > Kai Uwe Koch wrote:
> >
> > > here are two addresses of companies located in Germany for small
> > > vacuum-casting equipment:
> >
> > That's not the same thing. Please correct me if I'm wrong, but I
> > understand vacuum casting to typically work in polyurethane, whereas
> > investment casting is for metals.
> >
> > --
> > Marshall Burns
> > Marshall@Ennex.com
> >
> > *****************************************************************
> > ***** ENNEX(TM) CORPORATION
> > ***** Fabbing the Future(TM)
> > *****************************************************************
> > ***** 10911 Weyburn Avenue, Suite 332, Los Angeles, U.S.A. 90024
> > ***** Phone: +1 (310) 824-8700. Fax: +1 (310) 824-5185
> > ***** E-mail: Fabbers@Ennex.com. Web site: http://www.Ennex.com
> > *****************************************************************
> >
> > For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
>
> --
> _______________________________________________
> Scott Rackey
> BurstPower Technologies
> sprackey@ix.netcom.com
>
> 23 Crescent Hill Avenue
> Arlinton MA, 02174
>
> (781) 648-4614 (home)
> (781) 648-4680 (work)
> (781) 648-4650 (fax)
>
> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
hello
just a quick note on titanium furnances scott.
these frequenly are not induction but work off an arc priciple.
the melt chamber holds the investment shell which is set so that
a curcible can be rotated over it for pouring.
the curcible itself is a water cooled copper unit.
the ti is suspended above the curcible and is a rod 6-12" in diameter
app.
the Ti rod is lowered to the curcible and an arc is struck between the
Ti rod and the
copper curcible.
As the Ti melts away it collects in the curcible and the rod is lowered
to maintain the arc.
The melting is normally done in an Argon environment.
When enough metal is melted into the curcible the rod is retracted up
and the curcible is rotated
inorder to pour the melt.
The danger is that if/when the curcible fails you have water in the
presence of a large electrical
arc. The water splits into hydrogen and oxygen and blows up. Thus the
chambers are usually classified
as vertical or horizontal blows.
One of these went up at a foundry in Oregon and they found the
monitoring camera from inside the chamber
was found about a quarter of a mile away from the plant. It was a
vertical blow unit.
Because the melting is done in this arc method you can not super-heat
the metal.
So, this is not quite the table top method of this thread.
Just for your information
bye
martin

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/



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