Modify tool offset value to ensure dimensional accuracy
When the workpiece error exceeds the workpiece tolerance due to the tool error of the Dongguan Cnc Machining for the first time or other reasons, and the machining requirements cannot be met, the workpiece can be modified to make the workpiece meet the required size. The method to ensure the radial size is as follows:
Absolute coordinate input method
According to the principle of “large reduction, small increase” in Dongguan CNC machining, the tool compensation is modified at 001～004. If the workpiece size is larger by 0.1mm when cutting the groove with the No. 2 cutting tool, and the tool compensation display at 002 is X3.8, you can enter X3.7 to reduce the No. 2 tool compensation.
Relative coordinate method
As in the above example, input U-0.1 at 002 cutter compensation, and the same effect can also be obtained.
The same is true for the control of the axial size. For example, if you use the No. 1 external tool to machine a certain shaft segment, and the size is longer than 0.1mm, you can enter W0.1 at the 001 tool offset.
Semi-finish machining eliminates the influence of screw gap to ensure dimensional accuracy
For most of the CNC lathes processed by Dongguan CNC, after a long time of use, due to the influence of the screw gap, the size of the processed workpiece often appears unstable. At this time, we can perform a semi-finishing process after roughing to eliminate the influence of screw clearance. For example, after rough machining the outer circle with No. 1 tool G71, you can input U0.3 at 001 tool compensation and call G70 fine turning once. After stopping the measurement, input U-0.3 at 001 tool compensation and call G70 fine turning again. . After this semi-finished turning, the influence of the screw gap is eliminated, and the stability of the dimensional accuracy is ensured.