Instructions surrounding MM_PER_ARC_SEGMENT

[tommylux]

About tab explains: Marlin has an option called MM_PER_ARC_SEGMENT that defaults to 1mm this option has now been replaced with MIN_ARC_SEGMENT_MM and MAX_ARC_SEGMENT_MM. What is the associated feedback to set these to?

[FormerLurker]

If those options are available, it means you are running a very recent version of marlin 2, and likely don't need firmware compensation enabled. However, if you do, just leave the # setting at 1 for now. Eventually I will get around to making firmware compensation more flexible.

[skl111]

Con you comment on this q&a @FormerLurker

https://github.com/FormerLurker/ArcWelderPlugin/discussions/215

[FormerLurker]

Sure! I assume you are using prusa firmware? If so, the defaults are fine, I tested them thoroughly.

If not, it depends on your hardware. 1mm max is fine. A min of 0.1 is ideal, but many 8 bit boards will struggle with values lower than 5.

If you give me more info regarding your setup, i could give more specific advice.

[skl111]

Sure, I am using and SKR Mini E3 2.0 on Ender 3's & 5's with linear rails on the x & y axis's v-rollers for x until i get those replaced with Mutants and Hermit Crabs

[FormerLurker]

OK, for the SKR mini (assuming v2 or v3 here), I'd leave it set to the defaults:

#define MIN_ARC_SEGMENT_MM      0.1 // (mm) Minimum length of each arc segment
#define MAX_ARC_SEGMENT_MM      1.0 // (mm) Maximum length of each arc segment
#define MIN_CIRCLE_SEGMENTS    72   // Minimum number of segments in a complete circle

That will give you pretty ridiculous accuracy, and your board shouldn't stutter at all on small corners. If do notice any slowdowns printing arcs of a shorter radius (a few mm), increase MIN_ARC_SEGMENT_MM to 0.25, which should still give you excellent results. I don't think it will be an issue on that board, however.

For older 8 bit boards, I recommend a MIN_ARC_SEGMENT_MM of 0.5mm, since some may struggle to print smaller segments. My MK2.5 does ok with 0.25, but it does slow down a bit.

I hope that helps!

[skl111]

It does, and do you have a link or info on these and how to use P in cura? //#define ARC_SEGMENTS_PER_SEC 50 // Use the feedrate to choose the segment length //#define ARC_P_CIRCLES // Enable the 'P' parameter to specify complete circles

[FormerLurker]

You never want full circles (p) when 3d printing, else you will get overlap, so it should be good as is. Neither cura nor arcwelder will make full circles.

Also, fyi, do NOT enable firmware compensation in arcwelder. Your firmware is recent, and compensation will reduce quality for newer firmware, like yours.