Circles not round

betamachines

Hello,

I have a problem with my circles. In CamBam I drew to circles and made a test cut on my CNC running DDCS3.1.
The circles are not round when cutting. At the start/end point of the operation there is a small almost straight line.

How can I correct this?

MACHINE INFO
- Brand new, self assembled
- Hybrid stepper motors
- Ballscrews on XYZ axis.

betamachines

Here are some pictures of two test I made with circles. I have marked the starting points.

AndreyB

check backlash on X