Can´t get my circles round!!

[marcialvergara78]

I used to cut very even round circles, but now, I dont now why, the are a little bit oblong (oval) and with a little bump. 
I'll post the G-Code. I've read about backlash, calibration, ect... What could it be?
If anyone can help me I would be very thankful. 

I have a Blue Elephant CNC Router 60x90 

Mach 3 Software

Windows XP OS working on an old computer

[seth.madore]

From looking at your code in a backplotter, it appears that you're doing a ramp move in XYZ to final depth. You're using rectangular tabs, I would recommend moving to triangular tabs, since most machines and endmills really prefer not to plunge in only Z.

Beyond that, I'd start looking at your machine and making sure every bolt/nut/screw is tightened, including your drive screws/belts.