PhotoVCarve problem

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gregk
Vectric Staff
Posts: 373
Joined: Mon Mar 05, 2018 12:34 pm
Model of CNC Machine: None

Re: PhotoVCarve problem

Post by gregk »

Jan.vanderlinden wrote:So here I go again still trying to get a better understanding of how the % slider works and its effects on a project.
Based on what I understand to be correct from previous posts, I put together an excel spreadsheet to
calculate the step over, and the resulting width of cut, based on the angle of the cutter, depth of cut, and a given percentage.
If in fact the percentage of step over is calculated from the cutter angle at a given depth of cut, then anything
less than 100% for any angle and or depth of cut, would result in "chip out" of the groves.
Is that why Vectric started the slider at 100% and went up from there?
The last cell shows either a positive number (indicating there is stock Between the groves), or a negative
number (indicating that you are simply recutting surfaces that have been previously cut) and therefore a causing "chip out".
I set it up with conditional formatting to either turn green for a positive number, (no chip out) or red for a negative number (chip out)
Looking for critique of my formula.

I guess that I cant post an excel file so here is a screen shot of my formulas.
FORMULA.JPG
The things that wake me up at 2:00 am.
Dear Jan,

The actual stepover is calculated as follows. First, we establish the maximum width of the cut, that is the diameter of the v-bit at the maximum depth. Then we multiple that by Line spacing %.
You're right that when Line Spacing is below 100%, then grooves may overlap (in the places that are 'dark enough'). I think this post shows an example of using Line Spacing lower than 100%:
https://forum.vectric.com/viewtopic.php ... ve#p238512

Just to contribute to the general discussion about settings for Photo V-Carve toolpath. From my own experience it is worth paying attention to the direction of grain vs direction of lines in Photo V-Carve toolpath.
In my case I was using line angle of 80 degrees. I was using a 3 mm single flute engraving bit and no matter how much I slowed the feeds down and reduced pass depth, it was chipping off the upstands between the grooves. Increasing the line spacing or even trying different materials didn't help.
With all of those failures the grain direction was horizontal. Once I rotated my board 90 degrees, so the grain was more in line with the direction of cut, I started getting consistent results with almost no chipping.

I hope that this helps.

Greg K

Jan.vanderlinden
Vectric Wizard
Posts: 594
Joined: Wed Sep 28, 2016 10:19 pm
Model of CNC Machine: Xcarve
Location: Columbus Ohio

Re: PhotoVCarve problem

Post by Jan.vanderlinden »

Greg,
thank you for the response.
I will try rotating my stock and see what happens.

Mike,
Thanks for that tip.
Incase anyone is still interested, here is the file.
CUTTER DOC AND STEPOVER 1.zip
(60.44 KiB) Downloaded 69 times
“I've learned so much from my mistakes, I'm thinking of making a few more”

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