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 reading
Fanning the Coals
It’s no secret one of my lusts is machining in metal and wax. Actually, machining any material is fine with me. Wax became my favored material because it machines so well, especially with very small tool bits. Primarily, jewelry CNC carving for lost wax casting (LWC).
But I have also machined wax for LWC casting in brass, and that also works very well. I am not involved with casting large objects. At least not yet. But I don’t have an interest in doing large scale sand mold type casting. That’s a whole ‘nother sideline.
My light weight Taig equipment is perfect for machining wax. Taig tools also do an admirable job on small metal cutting as well. I have milled everything from stainless steel to cast iron. I have had no problems with brass, at least the types I have machined. Like most metals, there are many alloys. I choose the easy to machine.
I recently viewed a railroading model project (a hand-car)* made by an old friend Ed Hume. It got me re-considering my old lust for live steam engines and locomotives. They are machined directly from metal. That fanned the embers again and created a bit of remorse that my metal shop hasn’t been productive as was intended, except for the LWC silver work.
*Don’t know how long this link will last.
I designed my shop and machine equipment size specifically to create model train and model engine components. Not (what I consider) full size, or real life-size components. The term often used is “Model-Engineering” workshop.
I recently dusted off one of the machines, the Proxxon PD400 mini-lathe and turned down some leaded steel stock into a mandrel and cap for my wax carving. That effort really felt good, experiencing those perfect cuts and… Continue reading
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.
No Mistakes – Making My Point
I seldom, almost never make mistakes… HA! But I found one in my tool definitions for Vectric Aspire. Um… maybe I do make a few mistakes.
I use a very fine pointed, down to 0.003 tip tapered ball-end milling bits. Tapered ball-end milling bits are defined by their one side taper angle and the tip radius in the Aspire tool table. That was what got me. The tapered bits are identified by the manufacturer with total (combined) taper angle and the tip diameter.
So, what the maker defines as a 10-degree 0.005 tapered ball-mill is defined in Aspire as 5-degree taper bit with a 0.0025 tip radius.
I got the side angle correct but I was entering the full tip diameter as the radius. I realized the problem when I would define stepover as a percentage rather than specified absolute distance. The percentage calculation was showing twice the correct distance.
Therefore, Aspire was also calculating the tool path to be twice as wide as it actually was. That’s because that is what I specified.
Hmm… wonder how long I have been doing that!*
I am trying to imagine how that would affect the milling operation. Probably some dimensional errors, the program calculating the bit to be twice as wide as it actually was. With the tiny bits, there error would not be noticeable or of any importance. Pocket sidewall distance would be a couple of thou’ too small.
I think the biggest issue would be the stepover. If I wanted 20% it would be cutting… Continue reading
Swarf Blower Added to Taig HS Spindle
The blower that was added to the Taig spindle on the original WAX milling system has been updated to operate on the new high speed water cooled spindle. A full article with pictures can be found here: https://thehobbyistmachineshop.com/cms/projects/wax-fan-v-2-0
This is not a dimensional, How-To article. It demonstrates how 3D printing can be utilized to add accessories to the Taig mill and a high speed water cooled spindle.