Hi i am getting not perfect circle ,and i don't know why,could somebody explain why is it like this?

Feed rate 2700 ,plunge 1000 ,20k rpmmatetial plexiglass 8 mm  o flute bit for plexiglas,0.5 mm ,17 passes

many cause:

- is your cnc perfectly square ?

- have you printed this : https://createforcuriosity.com/fr/design/rEMrG8nl/details

- did you have any play in X or Y ?

can you post some photos or video ?

0.5 mm difference on 1500 mm long,yes i use it with modification,

By play what do you mean?

0.5mm on 1500mm, it can be caused by a play between the leadscrew and the T8 nut

So what kind of best precision for hardwood i can get with topsie cnc heavy cnc ??