Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Wattie on March 12, 2021, 04:35:49 PM

Title: circles not round
Post by: Wattie on March 12, 2021, 04:35:49 PM
Hi first post here, been a member for couple of years, when I pocket circles they tend to be oval so I decided to try profile with a 15deg .01mm engraving bit and turns out that the start point is different to the end point, can someone please help would be much appreciated
Title: Re: circles not round
Post by: joeaverage on March 13, 2021, 12:50:58 AM
Hi,
interpolated circles will, and can only be, round if:

1) No backlash
2) No backlash
3) Correct steps per unit, both axes
4) No backlash
5) Related to 3), no missed steps in either axis, its equivalent to having incorrect steps per unit programmed. It as bad as backlash.....
have I mentioned that backlash prevents interpolated circles from being round?

Craig
Title: Re: circles not round
Post by: Wattie on March 13, 2021, 01:15:29 AM
lol, im pretty sure i dont have backlash but if I did can I just put a Number in the box and see if it help, and if so what would a good starting number be i.e .1mm, I have never really had any luck with perfect circles but spindle always returns exactly to zero so I'm pretty sure I'm not losing steps
Title: Re: circles not round
Post by: TPS on March 13, 2021, 02:25:16 AM
IMHO you should find the reason first, before putting weird numbers into backslash compendation.
it is not only on circles, your first Picture Shows, that the rectangle is also not closed at the lower
right Corner. it Looks like the same amount like at the circle.