Uneven V Groove

Hi everyone.

1st post on here seems like a lot of you really know your stuff and I'm hoping someone can help.

The company I work for recently bought a 8th hand 10ftx5ft cnc flatbed router with vacuum bed. Everything seems okay with it when cutting flat panels, letters etc but as soon as I try to cut a v groove for a tray sign there is different depths along my cut. It's 3mm ACM and I'm cutting at a depth of 2.2mm.

After stripping it down and adjust the sinking that was happening between the frame I had an allowance of 0.06mm which I felt was acceptable.

Low and behold I ran the file and same again. Managed to fold it on one edge and another was tough but it did fold. Just can't seem to get my frame, spoil board and vacuum any flatter.

I am in no way an expert and only know the basics but Google and YouTube videos have came to no prevail. All axis are true and level the fram is off but I've compensated for that.

Any help would be greatly appreciated.

Hi,
I don't know off-hand what the problem is with your setup, it may be mechanical, it may be electronic or even Gcode.

I make circuit boards by engraving. This process absolutely demands the best and flatest setup. If the cut is too deep the width of the remaining copper traces is too small, if its not
deep enough the copper layer is not cut through. The margin is about +- 5um, ie very demanding indeed.

I use Autoleveller, its a freeware program that allows you to probe the surface of the material, then is manipulates the Gcode to accommodate any bow or warp or other flatness issue.
I have used it daily for eight years, and could not make PCBs without it and I'd go broke.

Autoleveller - Autoleveller

Maybe it would help you to.

Craig

Quote:

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Originally Posted by Thatsignguy

Hi everyone.

1st post on here seems like a lot of you really know your stuff and I'm hoping someone can help.

The company I work for recently bought a 8th hand 10ftx5ft cnc flatbed router with vacuum bed. Everything seems okay with it when cutting flat panels, letters etc but as soon as I try to cut a v groove for a tray sign there is different depths along my cut. It's 3mm ACM and I'm cutting at a depth of 2.2mm.

After stripping it down and adjust the sinking that was happening between the frame I had an allowance of 0.06mm which I felt was acceptable.

Low and behold I ran the file and same again. Managed to fold it on one edge and another was tough but it did fold. Just can't seem to get my frame, spoil board and vacuum any flatter.

I am in no way an expert and only know the basics but Google and YouTube videos have came to no prevail. All axis are true and level the fram is off but I've compensated for that.

Any help would be greatly appreciated.

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If it isn't workholding then the obvious thing to me is tool deflection, possibly radial or axial play in the spindle bearings or axis.

Check your coupler on the Z-axis

Thanks for the replies unfortunately still no joy at this point I'm thinking of adding another 10x5 18mm sealed edge plywood between the gantry and the vacuum bed just for extra support. I'm convinced now the bed is dipping between the supports of the frame.

I'll certainly look into the coupler tho as this is new to me.

Cheers.

Mount a dial indication in spindle and move it around table with jog commands and see how flat your table is

Quote:

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Originally Posted by CNCMAN172

Mount a dial indication in spindle and move it around table with jog commands and see how flat your table is

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I agree, but maybe better to indicate the workpiece after clamping is applied.