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Author Topic: Anyone one else having weird problems with Mach, I think it's G41 or G42??  (Read 3182 times)

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Offline Tarak

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I've noticed that occasionally when running a program using G42 that I have run heaps of times correctly it stops on a certain line with the following error:
Radius to end of arc differs from radius to startLine 13
But when I shutdown Mach and reload the file, it works.

It also occasionaly gives me an incorrect profile such as the attached pic, I think I've narrowed it down to the tool offset G41 or G42.
This also comes good by restarting Mach oor occasionally reloading the file, see 2nd pic
I disabled the radius compensation, and (touch wood) it hasn't happened since.
Comp is not something that you want to do out of the box :( It is NASTY and there are many places that you can get into trouble... I would say turn off comp and have your cam software takes care of it :)

That should fix you up

Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline Tarak

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Thanks Brian, I think your right.
Darc

Offline jimpinder

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Brian - I have tried compensation as well, and although not run any programs, I have noticed that it does not do what I think it should on the simulation.

I take it the theory of the G41 and G42 commands is that, if I and trying to mill the outline of a shape, lets say a simple circle,  then if I am cutting with a clockwise rotating tool, in an anti-clockwise direction, then if I set the tool to move round the circle at the required radius, the program will automatically apply (on G41) compensation for the radius of the tool, i.e. make the tool move out slightly, so the finished radius is correct - similarly with G42 - but on the opposite side.

When specifying left or right - does that mean the side of the tool you are cutting with, or the direction the tool will move when making compensation ???
Not me driving the engine - I'm better looking.
You need to look at it as you are standing at the start of the move and looking down the path... That is how you know if you need to use G41 or G42 (right or left side comp). If I were you I would do a straight line comp move (You need to make a move that the comp is taken out on) Also you need to be sure that you have moves longer then the tool Dia... If that is true you should not have much trouble.
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline Tarak

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Yeah it was definately tool comp causing my problems, it's still really weird how the program will display and work great, but ocasionally when I rewind and refresh it goes crazy with lines all over the place (and it actually moves as it displays, which is good that the display is accurate), but when I rewind and refresh or reload it usually comes good.............dah...nah...nah...nah (twilight zone)
The newest version of Mach3 should be better for you... it will show the comp toolpath on the screen (it may not be out but it will very soon)
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Darc the way your question was worded makes me wonder if your getting the offset canceled at the end of the code.

Wes
Have a nice Day