Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: BDF on February 26, 2011, 05:05:39 PM

Hello everyone
I've got a question. I'm trying to cut the 4 sides of a 5" x 5" x .5" alumin
plate to be perfectly square on my CNC A2Z mill.
I've placed a slightly smaller piece of 1/2" MDF on my table, my aluminum plate
on top of that and I've run a tnut/bolt right down the middle to clamp to the
table (my next MOP is to cut out a 4" hole in the middle of the 5" plate). My XY
part "0" point is the plate front left corner with lead in/lead out set as I'm
only cutting .0020 of each side one side at a time. I'm moving around the plate
in a clockwise direction. When I finish cutting all 4 sides, I checked for the
sides to be square. They're not.
Is the built in error of the XY table movement not being 90 deg. to each other
just the way it is or is there a way to account for this in M3 by having the CNC
capability to program the errors out? In setting up M3 and in the process of
squaring up the mill do you program M3 to shift over whatever amount it is out
of square over a certain distance of any XY direction of travel?
If so, where and how do you do this?
Thanks
Bruce

Bruce,
You shoould first check to see if the machines X & Y axis are perpendicular to each other. Also check the gibs are adjusted.
As single clamp in the middle of the plate may allow the Al plate to move when machining so make sure that is not the case.
If the machines axis are correct and the bolt is holding down the plate then you should be able to machine it square.
How much was it out?

Bruce,
I have used a formula: [Function Cfg's > Formulas]
f(y) = y + (x * .*********) or f(y) = y  (x * .*********) where .********* is the amount to correct
Y for X moves.
Has some limitations as formula function may not be active some other functions (ex: Go To Zero). Formulas would be much more useful in many circumstances if the limitations were fixed.
Best to square up mechanically if possible.
Hope this helps.
Regards,
John Champlain

Hey guys. It was operator error. My part did move ever so slightly. Part of the learning process.
My A2Z mill XY movement is dead on perpendicular to each other. I've got precisionitus/squareness on the brain right now trying to figure all of this out.
Thanks.