CNC Shark Forum

Hello All,
I'm carving the Last Supper, 10"X, 20"Y, .350"Z depth. A 1/4 end mill rough pass, then 1/8 ballnose finish pass. The problem is after getting about 1/3 into the finish pass the Z depth starts rising and the finish cutter is mostly cutter air. Any reasons??? Is this a machine problem(CNC Shark) or a software issue?
Keith

Keith,
First my simple solution.
Was the bit tight enough?
Was the bit dull, thus being forced into the chuck?
Unless it's too late, send the bit to zero and see where it ends up.
Bob

Good Morning Bob and all,
After posting last night I went back and went to 000, then dropped Z down 0.035 and then restarted the finish cut, 11 1/2 hrs later it looks great. Go figure??? Well thats the wonderful mysteries of CNC fun I quess.

Hi Keith,

So you went to 0,0,0. Was the bit where you expected it to be?

Then you dropped the z down 0.035 - at that point was the bit lower than the top of the material?

I've seen this as Bob describes - bit not tight in chuck. The other thing I've found is if the plunge rate is too high for the condition, then the bit doesn't reach the depth desired, but the Shark thinks it made it there and from that point of course, all bets are off on the z being correct for the remaining cuts.

I also wonder how sensitive the control box is to the quality of the power being fed to it. When I first setup my Shark, I hadn't yet purchased a power conditioner. I planned on it as the power out in the country side here is not consistent in voltage, I know that, and so had planned on it. I did see some abnormal behavior over the first few days before I received the conditioner and added it to the setup. Since then it's only been operator error, or trying to do something beyond the capabilities of the Shark - no mysteries.

Keith and Joe,
Glad to hear that the second attempt worked!
I'm still curious...Was the bit tight, or did it slide up far enough to bottom out in the chuck? If the bit was bottomed for the second cut, that could be a reason for success. Where any other variables changed the second time besides readjusting Z? Plunge rate is also interesting and could have contributed to the problem. Electrical too.
Was wire routing changed?
Anyway, I'm interested in the solution because it will probably happen to me and others.
Thanks,
Bob

...One more thing: Let's see a picture of your project.