"One Perfect Part at a Time"


Micro-milling Wax

0.005″ tapered mill bit

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. 

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Machining in the 4th Dimension

The fourth dimension is often mentioned in science fiction as a dimension beyond the human senses. Today, real scientists (if there are such people) claim the fourth dimension does exist. But there are IMHO plenty of pseudoscience, especially promoted as video “entertainment.”  Material for a future rant…

In machining there really IS a fourth dimension. Usually called the 4thaxis. The Hobbyist Machine Shop (THMS) has a fourth axis for use on the Taig micro mill. It’s been on both the mill used for metal machining as well as the wax milling machine. Currently it is on the Taig micro-mill used for wax carving

THMS has (owns) four software CAM software packages that can create g-code for the 4thaxis machining. I’ll list them but will not (here) get into the fine details of using them.

Two types of 4thaxis operations are most common.

First is indexing. The material to be machined is held in the 4thaxis rotational device. Standard X, Y, Z three axis machining is performed on the surface facing the Z axis. 3 axis machining is paused, and Z axis is raised to clear all dimensions of the material. The 4thaxis rotates (indexes) the material to another face. This can be 180, or 90, or 45, or any equal or non-equal rotation. Then 3 axis machining operation resumes on the new surface plain presented. Repeat as necessary.

The second process (A axis rotation) requires setting Z axis Y position perpendicular to the center rotational axis and A axis assumes the movements of the Y motion vectors by rotating. Where A axis was stationary in the first method, the actual Y axis is stationary in the second.… 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

Wax swarf blower system

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.

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