[AUSTINMACHINING]

So... I had a job requiring some specific material properties come up. It had to handle 400 deg C and be non conductive. I'm basically heating a device electrically at 10 amps @ 1.5 Vdc. using to electrodes I machined from copper. I had kicked around the idea of machining out of steel and having a coat of ceramic fired onto the surface. Did some research and found out Corning makes a ceramic that is machinable with metal cutting tools called Macor. So I designed the part and ordered a piece of 1.75" x 1.75" x 3". Piece of stock for $120.00. In the mean time did some searches on machining the stuff. After reading lots of horror stories (chipping,fracturing from too much holding force etc), I was very apprehensive about making the part, but my time table wouldn't allow outsourcing the part.

Looking at the manufacture's recommended cutting data, I thought it was a mis-print. Incredibly low surface speed required. 35 SFM. I had to machine all 6 sides with intersecting .07" holes and thread milling. This was going to take forever at those speeds/feeds. Oh well, too late to turn back now.

Job 1. Slice the stock down to 1.2" in the Z dimension. I don't have a saw that will turn that slow but I do have a slitting saw for the Torus with a .625 arbor. So went to home depot and found a 4" diamond cutoff wheel. The arbor was not an ideal fit, but doable. Ok, that worked good enough, but now it's time to machine.

After reading about work holding challenges, I decided to slice some soft aluminum (sheet metal type) to support the material between the steel jaws. I put enough pressure to hold the material for what I "felt" would work, and programmed some conservative depths of cut to reduce cutting forces. Then I made a make shift flood cooling setup required for machining Macor (I normally use high pressure mist). After a whole day of "pucker factor" I got the piece made and it came out GREAT!. Took an extensive amount of cleanup afterward. I hope to never have to machine this stuff again, but now I know I can.


Here's a short shaky cell phone video.
Macor Ceramic AM - YouTube

[rlockwood]

Ick..

[TiagoSantos]

That was nerve-wrackingly cool.. And now that I know that, I'm sure it'll come in handy some day hehe.

[kvom]

Pretty expensive material!

[hoss2006]

Yeah I remember working with that stuff at work, had to slice off dozens of parts about 1/8 inch thick with a slitting saw, bummer was it was on a manual bridgeport and took forever at the slow cutting speeds but at least I got paid for it.
Hoss

[CROSSHATCH]

Nice I have ceramic in my room from my brother; un-sintered though...