Using machinable wax to do proofs

Now that most of my issues with the x carve are resolved beyond some fine tuning, I thought I would start trying to do a real project. I didn’t want to jump in with a complex cut in 1/8" aluminum plate, so I started with machinable wax. I had some in 75mmx150mmx3.5mm plates. One issue right off the bat is the thickness varies a lot in this material, in the piece I started with it went from about 2.9 to 3.5. You have to be careful when you zero the bit to the top of the surface that you are not on one of the thin parts.

I bumped up the feed rates and cutting thickness from aluminum, after all the point is to test out parts without waiting all the time it would take to do the cut in aluminum. I did 400 mm/sec with .5mm cut thickness. That turned out to be conservative, I probably could have gone a lot farther. The material machines beautifully. There is no grain or anything, it cuts perfectly without cracking or chipping. The chips are kind of like snow, and are mostly blown out by the air current coming from the air cooled spindle. It looks like you can have a wall thickness of only .1 mm and it will not chip out. It is delicate so if you make any fine details, you have to be carful not to damage them with your hands. I didn’t use tabs, but instead tried to leave about .2 mm of material at the bottom like an onion skin. This worked OK, but was difficult to dial in due to the variation in thickness.

Anyway here is the finished construct, a pair of linked elliptical gears that will turn against each other. This is based on a similar part I saw on thingiverse for 3D printing. I made a new version from first principals, using autocad and cambam. Each gear is about 60mm on the long axis.


Very nice!
Although machinable wax seems like an expensive material to use for testing.
I use it for the final print because it machines so well. (I use it to create the masters for making a mold)

For just testing I use scrap MDF. (I scavenged a bunch of shelves from old ikea bookcases, They work great for test blanks and sacrifice sheets.)

I am looking forward to seeing the aluminum version :smile:

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Some of you may be interested in making the stuff yourself and saving a little money. I would probably use the more expensive stuff for final prototypes and for lost wax castings, but for the times that you are testing new methods or running many iterations of a prototype, then you might consider the following link:

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Can the remains of the wax (and even the wax swarf) be re-melted and then re-cast for future use?

Yes. If you clean your machine before you start machining the wax and contain as much as possible you can remelt it and cast it into any shape you want.
I love the stuff and test most of my 3D parts before I commit to metal.


How do you stick it to the work surface?

In the photo above the wax is screwed to the fixture from below. The fixture is 2 piece the base in clamped to the mill table and the top piece is dowel pined and screwed to the base. The parts made in Alu were pre drilled and taped. Had to make 4