Question
I have a Shoda Router with 15M Fanuc control. The issue we live with is we can’t cut anything faster than 200 IPM. When we run any faster we don’t get true square corners. We can program exact stop mode using the G61 command but that also slows the cycle time. Is there anything we can do to speed things up and get a square corner?
Forum Responses
(CNC Forum)
From contributor R:
You first must verify the mechanical condition of your machine. Inspect the linear bearings and ballscrews for wear and tear. You can then look at the software functions of your machine. Make certain the backlash compensation is properly set for all axes. Do you have the look-ahead function enabled on your machine? This will allow the machine to slow down on corners while running faster on straight lines. If you haven't had your machine serviced in the past year or two it would be a good idea to bring in a technician either from Shoda or an Independent to protect your investment.
The exact stop would be your best bet to get a true square corner if all of your ball screws are set and there is no backlash/play. It does mean a longer cycle, but the only other option is to program a slightly rounded corner. You do get faster production without the exact stop enabled but the controller is trying to slow down the machine when it approaches a corner. Then when it reaches that position it immediately switches and speeds up to reach the next destination. All CNC's will do this. They do calculate how to slow down and then continue. The only way to truly solve this is to use exact stop.
Some software for programming the machine will also trick the machine. They will program the machine to go beyond the corner, and then make a small arc outside of the panel and then come in tangent to the point they just left. This way the part is square in the corner and the machine doesn't slow down.
