suggestions for micro mill

[Hawkeye21]

I do not have a mill, but the application I have in mind would call for the use of a small CNC micro? mill: I would like to incorporate a video camera and computer with a CNC mill so the system can more or less automatically remove thin layers from a sample in a precisely controlled way. Once dark areas in the sample are revealed, the mill must avoid these areas. I have done this by hand using a 7X stereo microscope and a hand-held rotary tool (like a Dremel tool) and I found carbide drills in the range 0.010" to 0.020" work extremely well, but I have to be very careful and not go too deep. The samples can be quite large, so this would have to be done in repeated steps: Set up the sample, start the program to work on a small area (maybe 1" by 1") then move the sample and start over. I will develop the software, so that is not an issue. What I want to do though, is to start with a good reliable mill. I'm guessing a bit here, but I would think I would need repeatability in x,y,z of about 0.001" or better. Total travel in x of maybe several inches, a few inches in y and at least an inch in z. The material removed turns to powder, so I would need to use an enclosure and a vacuum system. I'm sorry to be so long-winded, but I felt to get a good recommendation for this unusual application, I would have to go into some detail. Thanks in advance.

[RotarySMP]

You quite often see high quality X-Y positioning units on Ebay, with very limited travels. One of these units could be a good basis.

[tikka308]

What are you thinking for the control? Are you going to program the electronics & photo sensor?

[Hawkeye21]

To get proper registration between the camera and the mill, I was thinking of making a "sandwich" of contrasting materials. Mount the sandwich to the bed, drill or mill small holes through the top layer so a contrasting layer shows, then use the camera with a frame grabber to capture the image. Knowing how far the mill moved between holes and how many pixels are between the holes in the image, you can figure out the scale and where the mill is. Yes, this would have to be done in software, but it shouldn't be too hard. I do have some experience dealing with images and interfacing to machines, but I have never used a CNC machine before.

I am hoping to get a grant to do this project, so money is not an issue - at least not yet.

Do you have any suggestions for a mill to use? The Cameron CNC Machining Center looked like it would do the job.

[Harryman]

Impressive stats on that machine, I've never heard of it. It would be nice to see higher quality images of it or better still, one in the flesh. What does one cost?

Check out Minitech's machines, similar specs and you can customize motors, spindle etc. to suit your tastes. A bit bigger work envelope which might be a liablilty for you, but would help for resale down the road if your needs change.

I've got one and am very happy with it.

http://www.minitech.com/itemdesc.php?ic=2

[mikkojay]

Can we ask what you are cutting?
Fossils?
Kryptonite?
Secret Stuff?
It sounds like an interesting concept- any more progress?
-Mike