Machinable wax for CNC
Posted by
Gordon Robertson
on 2001-08-13 14:27:54 UTC
HI gang...just going thru the old emails I saved for some reason or
other and ran acroos one about machinable wax.
I just thought those of you doiing CNC machining on wax might like a
few tips.
If your going to use your machined wax part as patterns for casting
purposes, hard machinable wax is NOT the best thing to use. I
recently had a sample firearms receiver poured from a CNC'd part I
made at school. The casting came out pretty bad due to cracks
forming in the ceramic shell during the burnout phase. These cracks
are caused by wax expansion prior to reaching the melting/burning
stage.
The best solution is to use a low temperature melting point (below
212 degrees F)wax. This type of wax can be steamed from the shell
mold leaving only a small residue which is easily burned out with no
fear of cracking the shell.
Machining soft wax such as via CNC this requires much slower spindle
RPM's and feed rates than would normally be used. Also, extra care
must be taken to clamp the wax well enough so it doesn't shift under
machining loads. One way to do this is to pour hot wax into some
sort of easy to clamp frame.
I've machined really cheap ($.55/lb) candle wax nfor this purpose and
it works just fine.
Smoke
other and ran acroos one about machinable wax.
I just thought those of you doiing CNC machining on wax might like a
few tips.
If your going to use your machined wax part as patterns for casting
purposes, hard machinable wax is NOT the best thing to use. I
recently had a sample firearms receiver poured from a CNC'd part I
made at school. The casting came out pretty bad due to cracks
forming in the ceramic shell during the burnout phase. These cracks
are caused by wax expansion prior to reaching the melting/burning
stage.
The best solution is to use a low temperature melting point (below
212 degrees F)wax. This type of wax can be steamed from the shell
mold leaving only a small residue which is easily burned out with no
fear of cracking the shell.
Machining soft wax such as via CNC this requires much slower spindle
RPM's and feed rates than would normally be used. Also, extra care
must be taken to clamp the wax well enough so it doesn't shift under
machining loads. One way to do this is to pour hot wax into some
sort of easy to clamp frame.
I've machined really cheap ($.55/lb) candle wax nfor this purpose and
it works just fine.
Smoke