Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Robotintheforest on October 25, 2017, 01:28:48 PM

Title: Help with discrepancy between CAD design and cut part.
Post by: Robotintheforest on October 25, 2017, 01:28:48 PM: Hi there I am having a problem where I am trying to cut out a test joint for a piece of furniture and I am consistently getting extra material left over on all sides. The attached pic shows a 100x100mm piece with a 18.2mm slot cut in it to slip fit a piece of plywood. I am getting a 100.6mmx100.6mm piece with a 17.6mm slot cut in it... way too tight for 18mm ply. It looks like I am getting an extra .3mm left on all sides. I am generating my code from fusion360 and cutting with a 6.35mm compression bit, generally my machine has been pretty accurate (Linear bearings and 1616 Ballscrews.) Backlash compensation is off.

Things I have tried so far:
-Restarting everything
-Turning CV mode off
-Re-calibrating the x and y axis using the calibration tool on the settings page. Calibration settings were fine.
-Making the part in Vectric (Was slightly worse 17.2mm slot)

Thanks!
Title: Re: Help with discrepancy between CAD design and cut part.
Post by: joeaverage on October 25, 2017, 02:00:57 PM: Hi,
sounds to me like your machine is compensating for the diameter of the tool but doing so incorrectly. Is the actual tool diameter
the same as the entry in the tool table? Is the current tool displayed in Mach match the tool you actually have fitted in the spindle?

Craig
Title: Re: Help with discrepancy between CAD design and cut part.
Post by: Robotintheforest on October 25, 2017, 02:44:31 PM: Quote from: joeaverage on October 25, 2017, 02:00:57 PM
sounds to me like your machine is compensating for the diameter of the tool but doing so incorrectly. Is the actual tool diameter
the same as the entry in the tool table? Is the current tool displayed in Mach match the tool you actually have fitted in the spindle?

Thanks for your response Craig, that's one of the things I checked but forgot to mention I had checked. They are the same on all counts.
Title: Re: Help with discrepancy between CAD design and cut part.
Post by: ger21 on October 25, 2017, 03:50:31 PM: Are you climb cutting, or conventional cutting?
Title: Re: Help with discrepancy between CAD design and cut part.
Post by: Robotintheforest on October 25, 2017, 04:13:34 PM: Quote from: ger21 on October 25, 2017, 03:50:31 PM
Are you climb cutting, or conventional cutting?

Climb, I'm inferring I should try conventional?
Title: Re: Help with discrepancy between CAD design and cut part.
Post by: Robotintheforest on October 25, 2017, 04:45:01 PM: Ok Thanks Gerry, you are a pretty cool guy 8). Totally fixed now measurements are bang on and the surface quality is way up also.