I am getting a slight variance in some investment cast white bronze pieces. The pieces are a little less than 1/16" thickness, and need to be "adjusted" by as much as .017" in some cases If you have worked with this stuff before, and have any ideas, please e-mail me, I have a few pics to help describe the issue... [email protected] THANKS!!! Mike
Are you doing plaster/sand investment or ceramic shell? (some foundries will do shell and call it investment to a client) What exactly are you "adjusting", the wax?
Is the shrink putting something in a bind? Could you do a post mold annealing cycle to stress relieve the cast? TZ
Sorry, the proper term is Daping... I am anything but a casting engineer... Yes, it is definitely lost wax. Funny thing is, some are dead on though... FLT-BLK, That's what I was thinking... What temperatures do you think we would be looking at to allow movement without distortion or damage? I believe that bronze has a much lower melting point, at least 400 degrees F below the Aluminum whose profile I would like it to conform to... Thanks guys...
What type of Bronze are you useing. Bronze melts at a higher temp.Bronze about 1800 F. Aluminum about 1200 f.. Warping or shrinkage can occur when pulling the wax, impropper sprueing of the wax, casting to hot, uneven cooling of the mold, care should be taken during these processes to keep the tempetures similar. The fact that some of the parts are right would indicate to me some sloppy foundry work. To rework these parts you need to work them cold uless you first have them cured by shot peening. A daping form is helpfull. An other soultion would be to recast them and not accept any that are not to specifications. Pogo
Is the problem in the wax ? Maybe the wax is too soft for such a thin section,and is distorted in handling before casting. Or maybe the wax wasn't cool enough when it is removed from the mold,causing distortion in handling. I'm guessing these are the small name tags for headlights. I'd be tempted to try reworking a few in an small arbor press with a block of soft urethane or rubber on the bottom.
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