Wax Machining
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.
Continue readingTaig Micro-Mill with HS Spindle
A video of my Taig mill with HS water cooled spindle running at 15,000 RPM milling wax double sided master for lost wax casting. Sorry about vertical format. I know better but filmed this originally for quick share with a friend on iPhone Messenger. Right click on image and open in new window for larger size and audio.
Ring Carved on 4th Axis
Everything came together for the first real use of the forth axis mandrel for ring carving. It’s nice when the plan comes together and everything works as intended. There was of course far more than just making the mandrel. There is the CAD design stage and the CAM (Desk Proto) for generating the G-code for the 4th axis. Then running the G-code on the micro-mill. I use LinuxCNC and I had to write my own metric post processor for Desk Proto. Not all that hard, actually. I made a USC (inch) version too. One tiny code change.
The first picture is the carved ring blank on the mandrel. I can accommodate a wide range of wax sizes. There will be much more experimentation and determination of the correct wax width for a project. This example worked fine.
The second photo is after the wax master model was hand finished and at this point is ready for casting. Sprue’s were added the ring put into a flask and the investment added. This post is not about the lost wax process. However, I thought it was interesting to show the wax carving and the final result the mandrel helps create.
The last picture is the finished Sterling silver ring shown on my hand (size 11). It really looks great. I will be doing a lot more wax carving on the 4th axis of the Taig micro-mill.
Wax Carving Mandrel
Plastic prototype and machined steel wax carving mandrels.
This is the finished mandrel turned from 12L14 steel as well as the prototype that was 3D printed. The steel mandrel will hold the green wax (in the photo) that will be machined into a ring on the rotary 4th axis of the Taig CNC micro mill. A 1/4-20 thumb screw will be fitted into the end for drawing down the cap, acting as a clamp for the wax.
The wax is purchased in a tube with the center hole existing. The wax will be sliced in widths greater than the ring design I will be milling. Then the hole will be manually (by hand) increased to the proper ring size after carving.
That’s the plan. It should work well for thin rings that don’t need side machining detail. Such as wedding bands or rings with engraved designs just on the top surface.
I am now contemplating wax holder designs for other styles of rings, pendants, and charms. Perhaps small LWC figurines. I can utilize the 4th axis on the mill for indexed flip rotation as well as continuous 360 degree rotation.
Steel end cap bored out
DeskProto stopped producing their 123WaxRing system. So I may borrow some ideas from that process. Seems the problem may have been the special wax shapes required were expensive to produce in low volume. I will design around standard available wax shapes, or as I do now, utilize slices off larger stock (bulk) wax. I have already been doing that for years using Freemen Waxes.