Circles not round if acceleration to low

[Tobe91]

Hello,

I got a question regarding the axis acceleration and cutting circles.
I just reworked all of my electronics of my CNC. I'm using an AXBB-E.

When I made my first tests with the new electronics in Oak Wood trying cutting circles with 10-40mm diameter.
So I cutted 10mm, 15mm, 20mm.. circles with following settings:
8mm 2-flute 15° cutter
3200mm/min feedrate
300mm/s² acceleration

With these settings the circles haven't been round (10mm circle was around 9,6-10,01mm in diameter).
I thought something was wrong in my axis setup or so, because it looks like the acceleration was to low compared to feedrate maintained.
Shouldn't UCCNC adjust the feedrate to stay on the tool path even if the acceleration is to low?

Later on I changed the acceleration to 750mm/s², everything else remains the same.
Now the circles have been perfectly round (10mm circle was in the range of 9,99-10,01mm).

Do you have some explanation for this? Is there some bug?

Thanks, Tobias

[cncdrive]

I don't know an explanation, but there was never and is no such bug.
It has to be something about the machine or about the chipload.

BTW, what do you mean by "not round"? Is it oval? Or is it segmented and not round?

[ger21]

Are the "circles" made of G1 line segments, or G2/G3 arcs?

[Zed_UCCNC]

Have you enabled backlash>? If yes, what are the backlash numbers?