Re: [CAD_CAM_EDM_DRO] Digest Number 1262
Posted by
Andrew Werby
on 2001-04-09 16:02:45 UTC
Jon Anderson <janders@...> wrote:
Subject: OT: lost was casting equipment, DIY
Since the topic of lost wax has surfaced, I have a question for anyone
involved in the process, especially anyone that has built their own.
I am interesting in making a centrigual spin caster. Used these years
ago when I used to make jewelry. I watch for them on eBay, but they
seldom show up. I've thought about making one using an electric motor
with flywheel, and a clutch between this and the spin casting unit.
Would not be hard to scrounge all the needed parts, but have never seen
it done this way. Obviously a large spring is much cheaper and easier to
mfg, but for a dumpster diver like myself, the motor/clutch would be
easy to put together for next to nothing.
The one thing I'm not really sure about is just how fast the spring
models spin on average. Anyone have any idea?
Jon
[This isn't that far off topic really, after all, making something on a
CAD/CAM system is often part of a larger process which can easily include a
lost-wax casting step. It's no coincidence that a lot of people here seem
to know a lot about it. It's a process which is well-suited to reproduction
of the odd-ball sorts of parts one can make using these systems, and it's
often easier to mill a part in wax, pull a mold, and make multiple wax
parts for casting, than to make multiple metal parts directly via CNC.
Anyway to get back to the question, we built a home-brew centrifugal
casting machine a while back, using square steel tubing and a larger size
of same for sliding component holders- one held the crucible, another held
a cradle for the molds, etc. Nuts were brazed on to hold the screws which
would clamp the part in position. It is very adjustable, but I spend a lot
of time picking splashed metal out of the works. We thought about using the
motor and clutch, like you, but ended up using a spring from a Jelrus
Thermatrol. In retrospect, I'd say go with your instinct- the motor might
have worked better. The spring starts out with a lot of force, but slows
down rapidly, which is bad, because the metal starts dripping out of the
mold if it gets too slow. I end up sticking something down there and
goosing it along at the end. The motor wouldn't have this shortcoming. I'd
say about 100 rpm would be about right. The clutch would let it engage at
full power, which the motor will like better than being asked to start
under load. The metal needs that kick, right at the start, to shoot the
metal in there. I don't think you'd need a flywheel if your motor was big
enough.]
Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com
Subject: OT: lost was casting equipment, DIY
Since the topic of lost wax has surfaced, I have a question for anyone
involved in the process, especially anyone that has built their own.
I am interesting in making a centrigual spin caster. Used these years
ago when I used to make jewelry. I watch for them on eBay, but they
seldom show up. I've thought about making one using an electric motor
with flywheel, and a clutch between this and the spin casting unit.
Would not be hard to scrounge all the needed parts, but have never seen
it done this way. Obviously a large spring is much cheaper and easier to
mfg, but for a dumpster diver like myself, the motor/clutch would be
easy to put together for next to nothing.
The one thing I'm not really sure about is just how fast the spring
models spin on average. Anyone have any idea?
Jon
[This isn't that far off topic really, after all, making something on a
CAD/CAM system is often part of a larger process which can easily include a
lost-wax casting step. It's no coincidence that a lot of people here seem
to know a lot about it. It's a process which is well-suited to reproduction
of the odd-ball sorts of parts one can make using these systems, and it's
often easier to mill a part in wax, pull a mold, and make multiple wax
parts for casting, than to make multiple metal parts directly via CNC.
Anyway to get back to the question, we built a home-brew centrifugal
casting machine a while back, using square steel tubing and a larger size
of same for sliding component holders- one held the crucible, another held
a cradle for the molds, etc. Nuts were brazed on to hold the screws which
would clamp the part in position. It is very adjustable, but I spend a lot
of time picking splashed metal out of the works. We thought about using the
motor and clutch, like you, but ended up using a spring from a Jelrus
Thermatrol. In retrospect, I'd say go with your instinct- the motor might
have worked better. The spring starts out with a lot of force, but slows
down rapidly, which is bad, because the metal starts dripping out of the
mold if it gets too slow. I end up sticking something down there and
goosing it along at the end. The motor wouldn't have this shortcoming. I'd
say about 100 rpm would be about right. The clutch would let it engage at
full power, which the motor will like better than being asked to start
under load. The metal needs that kick, right at the start, to shoot the
metal in there. I don't think you'd need a flywheel if your motor was big
enough.]
Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com