Micro-milling Wax

Perhaps not worthy of a VMC but wax milling is a good job for a mill like the Taig. That implies the Taig is an excellent machine for the job.

As shown elsewhere in this blog, I have converted the standard Taig (not ball-screw) to a water-cooled spindle capable of 25,000 rpm.

The spindle is overpowered for wax milling. It just loafs along at near idle power. I turned off the water flow and let the mill run for an hour without water flow. The spindle became warm, but no where near hot. A lot cooler than the Taig standard CNC spindle motor doing the same work.

I have said wax milling is very low load, so this doesn’t surprise me. It tells me my cooling system is certainly far over engineered. Water flow is slow enough that wastewater (down the drain) cooling is certainly feasible for short to perhaps medium milling. The flow rate needs to be the smallest trickle. I would suggest collecting the (clean) water for plant watering or other uses. 

When I began the conversion, I had no idea of the requirements for a water-cooled spindle system as far as flow and radiator size. Experience with wax milling shows it is far less than I expected. Running the spindle near full load would certainly be far different. I would not downsize my water radiator or flow system. I just feel very confident it will handle any heavy work I may tackle in the future.

I just re-tuned my Linux-CNC software for the Taig wax mill. It probably has several hundred hours run time since new. I am also using very good Vactra #2 way oil. It has slight lube odor but superior “wetness” cling to the vertical column ways as well as the bed ways. I use it on the feed screws as well. (Taig recommended.)

Point is, the mill has microscopically “worn in” and is using a very good slippery lube. I re-ran the stepper tuning in Linux-CNC and can easily push X and Y rapids to over 60 in/min. with no strain on the half inch back and forth reversing test. I set the software for 60 but never need to run more than 30-35 rapids, I run Z about half that because gravity increases the load reversing from down to up. The Taig recommendation in their full package systems is 30 in/min rapids.

I was also able to push acceleration up a few more tenths. The steppers are still singing a sweet tune.

On a very small machine like the Taig, carving small wax jewelry masters, two-inch travel is BIG. High rapids are not necessary and in fact, quite hard on the machine hardware. A couple of minutes milling time in a several hour run has no value for the hobbyist.

High speed rapids is not a “brag point” on any micro mill. Smart owners protect their investment and hardware life by keeping operational wear and tear to a minimum. At least that’s my plan.

I am a Taig dealer, so I am at least a bit biased. However, the Taig Micro-mill, with or without ball screws is an excellent machine in its size class when used within its work-envelope capabilities. Wax milling is certainly at the very easy side of the envelope.

My other (first, 2 decade old) Taig Micro-Mill has handled brass, steel, 303 stainless, synthetic marble, cast iron… everything/anything I can place on the bed. A quarter inch mill is a big tool. I have run 3/8” flat end mills for surfacing and edge finish. Never as a “hogging” tool. The machine is not designed or intended for that. This mill also has mist cooling installed to extend tool life and easier cutting.

Bottom line. Wax carving is an excellent light duty (no mist required) application for the Taig. It can do most standard metal milling without struggle. It’s a mill intended for small tooling. If operation is wearing out or breaking belts, you are asking far too much of the machine. Period.