[cordvision]

I just cut some profiles and it turns out that the parts come out slightly too large. The CAD model is accurate, but the milled parts are both in the x and y axis about 1/64 inch too large (larger than the dimensions of the CAD model). What could the issue be, and how can I correct for it? I assume there is a better way than just making the actual CAD model by 1/64 inches smaller, right?

[bhurts]

First thing to do is check that your tool mics the same as its listed size.

Ben

[cordvision]

Thanks for your reply. I just measured some of my tools, cheap Chinese ones as well as some american carbide tools. They all seem to be slightly too small. Is that normal or am I measuring wrong? Also, where would I compensate for the difference, directly in Mach 3 or would I enter the true (measured) value in the tool library of my cam program? Are there other ways to add a small offset?

[hjl4]

Was is working fine before?
Is this a DIY retrofit? Could be the results of a badly configured #of pulses = 1 inch in settings. (motor tuning)?
Incorrect tool size?(doubt it). Well not 1/64". Even the Chinese don't make such a huge mistake.

On another topic, and not to hijack your thread, I managed to find a Made in Canada snow shovel last night. Of course at more then double the Chinese price. I guess that's all we Canadians know how to properly manufacture nowadays.

[cordvision]

It's a brand new Tormach PCNC1100. What would be the correct steps to compensate other than making the CAD model smaller?

[Dylwad]

Tool diameter in cam should be the actual diameter. You can play with this value to get parts the proper size too.

Check for backlash and that 1" of movement on the screen is 1" of actual table movement with a dial indicator too. Even better to make sure 6" is 6" of movement. There will be small differences.

Also did you use a finishing path? How big was the part?