Optical probe

[cip]

I don't know if there is even such a thing but i would like to replace my mechanical probe with something like an optical probe. I,m really tired of the inconsistancy of the mechanical one.

Any help would be appreciated.
Mike

[rb99]

Would that be the same as a 3d laser scanner?

[cip]

Actually, what I am looking for is the ability to trace a 2d pattern such as a template.

Mike

[bob_s]

Mike
That can be done very accurately using a digital camera and the proper setup. If you have a number of them, they can be done with a single setup. Then the vectors could be produced, that would be scalable or exact size, without tying up your system doing scans. Let me know if you want more info on how to do it this way.
Bob

[taskins]

Bob -
Will your digital camera-scanner work with 3d applications? Check out this thread under indexer http://www.talkshopbot.com/forum/showthread.php?t=11066

Thanks

Tim

[cip]

Bob
I would be very interested in learning move about this process. If you could supply more info that would be great.

Mike

[bob_s]

the only tricky part is to take a photo without any distortion. To do this use a digital camera with a slightly telephoto lens. It needs to be fairly free from distortion, but most modern cameras are. To aim the camera you need to make a mirror target. It is a flat piece of mirror with a cross or x in the center.
1 Place the center mark of the mirror in the center of your pattern - be certain that the mirror is perfectly flat against the pattern
2. line up the camera, on a tripod, or some other support so the reflection of the lens is exactly centered over the x - this is very important - but quite easy to do - it will keep your camera perpendicular to within about 1/10 of 1 degree in 3d space
3. remove the mirror if it covers any details you need
4. place a legible scale in the image
5. take the picture with fairly "flat" lighting - no very dark shadows
6. use the photo to trace with a program capable of making accurate Bezier vectors. Photoshop, Corel, Adobe illustrator, Aspire, etc
for some objects an auto trace program works well, but often it is faster to just create your own rather than fix an "automatic" one

After some practice it is very fast and accurate. I found that a clear photo, without distortion is the necessary place to start. If the patterns will fit on a regular photo scanner, that will also work, but most are limited to 9x14"
once the camera is set up you can photograph many patterns in a matter of a few minutes.
Bezier curves of the variety that Adobe or Vectric uses are the best way to define a shape. Don't hesitate to zoom in on the photo to adjust your points carefully.
The resulting files are small and scalable. The process does take some patience to learn, but the skills used to edit bezier curves are really the basis of most CNC layout and therefore I think it is worth the time investment.

[cip]

Thanks Bob, sounds fairly simple with a little practice.

Mike

[rb99]

Perhaps you could try a blueprint scanner? There are graphics places that scan blueprints for architects quite reasonably.

RIB