What Happened Here I Wonder?

Attachment 451884

So I'm new to all this and I was playing around with the piece in the picture. It is a pocket cut around the letters and inside the box. The shaded area on the upper left is a few thou lower than the balance of the pocket. Originally, I had a toolpath at about .035 for testing purposes. That one left an area under the lettering a bit higher than the balance of the pocket. My second toolpath was at .07 and it went a little deeper in the shaded area. The equipment is a Sainsmart Pro ver 3018 (Yeah, I know it is a cheap piece), Vectric 2d, and Candle processor. Why the lack a consistent pocket floor?

Thanks in advance for your help.

What does the preview in VCarve show? .07 is 2x as deep than .035.

I don't think it is a machine issue, you have some unwanted vectors in there. Post your Vectric file and we'll have a look.

Thanks for having a look.

Sorry for the delay, I was sidetracked.

I am far from an expert but I could not find anything that would cause the glitch.
Try setting your toolpath to Raster, rather than Offset, and set your 1/8 endmill stepover to ~30%. Set the Profile pass dropdown to “Last” if Vectric 2D software will allow it.
You’ll find that in most cases the raster selection is much faster than Offset.

I use Aspire so I’m not sure what your tool pathing options are.

My version of VCP is too old to open your file. Does it do the same thing in other files? Can you post the gcode?

I would guess it is the machine. The cutter must lift to move to the different pockets, and if the Z axis ball screw or assembly has any play this can happen. You can easily check the gcode for errors. Look thru the lines of code (open with notepad) for the z movements. You will see values that corresponds to the depths of the cut. If the numbers are what they should be, it is not the gcode. If your simulation appears correct that too is a good indicator.

Another option is your hold down. The cutters apply forces to the piece when cutting. That force can lead to movement if your hold down is not great. This problem typically appears as sloppy cut levels and not uniform planes, but it could be part of the culprit.

Bruce, Thank you for taking the time to look at the file.
Grant, I have attached the g-code file so you can have a look.
Brad, I'll look at the g-code file. Sounds tedious but necessary.

I'll report back if I see anything. Thank you all once again.

Nothing wrong with the code. All the final z moves are -.070 with a feed of 10. At that feed rate I sure wouldn't expect any over run. But if it's a leadscrew drive with some backlash, maybe something is binding intermittently and changing the actual depth. The only way to find that would be to mount a dial indicator on it and watch it thru the cycle. But of course it will make a perfect part then ;-)

If it were something gummy like aluminum it might be the cutter loading up, and then clearing itself either as it cuts, or on the next plunge.

Like Wes, I don't see anything wrong with the gcode. You could flip the piece in the software, mount the material in the same location on the bed and run it. If the depth issue is in the same place WRT the xyz axes, you know for sure that you have a problem with your Z gantry hardware. If the depth issue moves to the flipped corner, there is something in the gcode that we are missing.