cutting circles

[Thermoman]

I have a problem with my cnc shark--when i'm cutting circles it leaves a notch in the circle has any one else have this problem?
Not sure it its hardware or software issue!!

[sharkcutup]

Are you using plunge or ramping when starting the cuts?
I have noticed when I use the plunge method there is a slight notch that I usually just sand out. But when I use the ramping method the notch seems to have disappeared. The only thing I could determine as the cause was the amount of resistance versus z-axis play being applied during the plunge method.

Hope this Helps!!!

Anyone else out there have this same issue we would like to read your comments on this!!!

Have a GREAT DAY!!!

Be SAFE around those AWESOME machines!!!

[FixitMike]

When you plunge, machine deflection causes the end of the bit to move, usually in the -Y direction. One way to demonstrate this is to use the bit to make a hole using the drill toolpath. You will find the hole is not a perfect circle, even though you told the machine to move straight down. Also, pull up on the router motor, and notice how the end of bit moves away from the gantry. That is the problem.

Possible fixes:
Use a plunge cutting end mill.
Use ramps at the beginning of cuts.
Slow down the plunge speed.

[Thermoman]

Thanks I will try that I'm sure that I'm using plunge I'll let you know if it works for me.