NEMA 23 & Universal G-Code Sender: Adjusting Step Size?

Hi - I’m just doing some test carves before going on to manufacture a bunch of product (for the first time :sunglasses: ) and today I tried out my 90 degree v-carving bit on some expanded PVC.

The depth was 1.5mm, DeWalt 611 @ lowest setting, and feedrate for the first pass was 4000mm, then a second at 3000mm to try to clean up a bit. I was not pleased with the sides though - you can see in this picture:

They appear wavy, and a friend said to lower my step distance. Now I don’t think that’s an option in Fusion 360 that I’ve seen (correct me if I’m wrong), but there is an option in the Universal G-Code Sender application under the Machine Control tab:

I thought this was just applicable to manually moving the machine around, but is it actually setting the step distance for the carves that I send through it?

If so, what is the minimum step distance of these Nema 23 motors, and what is a good step distance to work with for something like engraving with a v-bit? (I’ll be using MDF primarily)

Any help is greatly appreciated!

Thank you

The steps you see in UGS are the steps you want the x-carve to move by jogging, but what you want is to calibrate the steps/mm in the grbl settings. So that the machine actually moves 40mm and not only 39.90mm. Search here on the forum for stepper calibration

There’s 2 potential steps and both are CAM related (not UGS):

  1. step over: the amount the bit steps over between passes. For instance a 0.25” bit with a 40% step over moves over 0.1” so it’s only cutting 40% if it’s diameter. The higher the step over, the more the bit is removing per pass. For a Vbit, since the point is small, depending on what value the CAM is using, you may need a really small step over.

  2. depth per pass or I guess it could be called a step down size. This is how deep the bit goes into the material each pass. I believe with a Vbit that this should be relatively low but I don’t know enough to comment either way.

Fusion360 offer stepover as a separate parameter.
Depending on tool strategy the naming may vary:

For 2D Adaptive its called “Optimum load” under the Passes pane.
For Facing its called “Stepover” under the same pane.
Not all strategies have stepover as an option because they are not relevant.

All of this has been very helpful - I’m going to start with RobertCanning’s suggestion and go from there. My table was also not very steady either (temporary situation until I build a new one) so I’ll be moving it to the floor for the next test.

The machine is pretty much brand new, so maybe I’ll re-tension the belts and reduce my feedrate to…2000mm @ 16000 RPM ?