Mach3/Sheetcam problems

[BensPlasmaAu]

Hi all,

I am still having issues with poor accuracy of cutting circles, where the top and bottom are out of round. Every drive gear is solid and has been roll pinned to cancel out any slop/backlash in the machinery.

I have entered the floating torch holder z switch offset into SheetCAM via editing the g code post 4.5mm. In Mach3 the z axis offset is only .0567 (I can only assume this is in mm as everything is set at mm). Where is this going wrong and how do I get them to match properly. I also can't remember how to do this, absolute mental blank. I don't have Internet or reception at the workshop so it makes it hard to research how to while attempting it.

I have also taken my motor tuning steps per mm and transferred them across to the HUB utility and saved it.

I was wondering now if I needed to enter in the steps per mm into sheetcam somewhere? Could this out of round/loss of steps be related to the two programs not talking to 3 achieve other properly?

I also started a cut where it was concentric circles as a test. It cut the first circle properly and then continued through the g code program, but the torch never fired again. Anyone got any ideas on this one as well?

So many questions which are probably all easy fixes where I've overlooked something, but even though I've read the manual a few times, I can't figure it out.

Thanks again!
Ben

[BensPlasmaAu]

More information. I mounted a pen to the gantry and drew up 50, 100 and 150 mm lines. I then measured what the table drew. So it turns out my steps per were out by a bit. So I calculated them and changed the x,a and y axis (all these are the same 3:1 belt drive and rack and pinion sizes). I'm not so sure that's going to solve my dreadful looking holes. Anyway I've set the steps per, acceleration and velocity as per the picture below. Is this roughly right? Im not sure the acceleration is high enough?????

Some Mach3 screens. This one showing my z axis offset. Nowhere near what it should be and it's been setup properly in the hub utility.

[acourtjester]

If your circles are out of round the movement of X and Y are not calibrated correctly. Trying to calibrate them manually can be a problem and using CandCNC's mach pages the Mach 3 calibration is not displayed. A simple way to help out is to change screens and run the steps per routine in Mach.
How you do this is start mach and go to the view pull down menu and click on load screen this will bring up the mach folder with the a few screens listed. Click on plasma.set this will make the screen go gray for a few seconds then display the normal Mach 3 screens and you can go to the setting page and run the axis calibrations as normal for X , Y, and Z and they will be in the set in Mach as normal. To go back just repeat the above and change the screen back to CandCNC's for your setup mine is DTHCIV-TAB.set. again gray screen then back to where you started.
The Z axis has no effect on shape of circles.

[torchhead]

I could answer but admin deletes (most) of them. Use the Support Forum

[BensPlasmaAu]

Thanks yet again acourtjester. As always some great ideas and options to diagnose the faults i seem to have, made especially tricky by remote control . I'm heading out to the workshop tomorrow and I'll give that a go straight up. Hopefully it's a winner and I can get some good cuts happening soon.

Torchhead, pm me with your ideas. But I can't see why your posts would be taken down by admin.