Circle not round

[edcross]

Try to create a 12" circle , Mach 2/3 atc nc pp , Mach 4 v 4612 , warp9 stepper board . When i run it on CNC the circle cuts 12" x 12 / 1/4" ????


Thanks

Ed

[ohiolyons]

Is this a new occurrence? Has it worked before properly? Helpful to diagnosis your issue.

Is this a brand new machine to you?

Assuming you are using the proper PP, have you modified your PP?

The actual file CRV or CRV3D is more helpful.

Have you checked you fittings? Are they all tight?

[Leo]

Looks like you have 24,000 RPM at 60 IPM

That is a chipload of .0006 which it WAY too low. You can burn your cutter that way.
Either slow the RPM of increase the feedrate to get chipload to at least .003-.005

That will NOT fix the issue, but I wanted to make you aware of that.

First go through all your ball screws, and anything you can find or get to and make sure everything is tight, no slop. Make sure everything is lubed and clean.

My guess is that you need to calibrate the X and Y axis for the correct steps per inch.
I have Mach 3 - so I don't know haw to do it in Mach 4.
THIS - will most likely fix the problem.

[Tailmaker]

If is it oval with maximum and minimum radius parallel to the machine axes, then it is likely the before mentioned axis calibration or maybe some flex or slop.
If the min and max radius are diagonally to the machine axes (a bit difficult to assess, though), then it would be a non-perpendicular gantry.

[phill05]

I remember reading on a cnc site quite a while ago that there were some problems with the Firewire gantry, make sure each side it is trammed up square to each other and no tight spots each side to throw it out again.

[edcross]

Recalibrate all axis with Mach 4 Wizard , still cuts around 1/4" off . 12" in Y 12 1/4" in X , does not matter if i cut outside - on line - inside tool path .

Ed

[Leo]

Hmmmmmm,

Something loose somewhere??

I don't know anything about calibration with wizard.
Does it adjust steps per inch?

I initially thought maybe it was acel/decel but you are only cutting at 60 IMP which is really slow anyway.

What material?
Which direction is the grain running?
Can you turn the material 90 degrees and try again - does dimension change with grain?

Can you post your .crv file? Don't post anything that is copyrighted.