Tom,
A lot of the problems on answering your question relates to the
complexity of the casting. I can give you a recent example although
this is not necessarily always the case.
We have just completed a very complex core model for a one off casting,
to produce the pattern in the traditional way, the core box and first
sand core would have cost in the region of £12k and would have taken
approximately 3 weeks to complete. Using our sand sintering machine
(EOS-S) we completed the sand core in 4 days at a cost of about £1k.
As I said earlier this is not always the case. One other thing that has
to be taken into account is that this process gives you the same
problems as Investment Casting, that being you only have one pattern,
so if you have any problems at the foundry you have to manufacture
another model, unlike having a core box made where you have a very
quick way of producing replica cores quickly and cheaply, unless you
have forseen a possible problem and built 2 models at the same time if
bed capacity allows. There is also a problem with out-gassing on
sintered cores, as long as the foundry is aware of this they should
have no problems in working with this process, but this has to be
thought about if you want to use this route effectively. I hope this
goes someway to answering your question.
Graham Tromans
Rover Group
-----Original Message-----
From: tomr
Sent: Thursday, March 25, 1999 8:05 PM
To: graham.tromans
Cc: tomr; rp-ml
Subject: RE: QuickCast in a hurry
Yes, shell molds from SLS are certainly a way to go.
How does the cost of an SLS sand mold compare with the cost of an RP
pattern
for shell molding, either of which is destroyed in the making a single
casting?
At 12:36 PM 3/25/99 +0000, you wrote:
>Tom,
>I think I may have missed the earlier parts of this thread, so I do
not
>fully understand your requirements. One solution we have used for
>parts in small quantities that would normally require a pattern set to
>be made, is to use the Sand Sintering process. We find most foundries
>have no problem with this, because you supply the full sand set and
>they just pour it. No draft angles required.
>
>Graham Tromans
>Rover Group
>
>-----Original Message-----
>From: ATiburon
>Sent: Thursday, March 25, 1999 2:44 AM
>To: tomr
>Cc: ATiburon; rp-ml
>Subject: Re: QuickCast in a hurry
>
>In a message dated 99-03-23 11:25:14 EST, you write:
>
><< >> Dan: We pour ductile iron (3-1/2 weeks) from RP patterns
>(1-week). >>
>As I understand, ductile iron, is done more commonly in sand casting.
>The
>patterns need to be either designed for that process, or converted into
>patterns that would work, as a matchplate for instance. Most sand
>casting
>foundries aren't geared towards prototype work though. That is the
>process I
>would investigate rather than investment casting.
>Andy Scott
>Lockheed Martin Aerospace
>
>For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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