What causes machining centre accuracy to deteriorate?
First, the poor machining accuracy of parts
Generally due to installation and adjustment, the feed dynamics between the axes is not adjusted according to the error, or due to the use of wear and tear, the machine tool axis transmission chain has changed (such as screw play, pitch error changes, axial fluctuation, etc.). Can be solved by readjusting and changing the amount of clearance compensation. If the dynamic tracking error is too large and alarm, you can check: whether the servo motor speed is too high; position detection components are good; position feedback cable connector is good contact; the corresponding analogue output latch, gain potentiometer is good; whether the corresponding servo drive device is normal.
Second, the machine tool movement caused by overshoot bad machining accuracy
May be the acceleration and deceleration time is too short, may be appropriate to extend the speed change time; may also be the connection between the servo motor and the screw is loose or rigidity is too poor, may be appropriate to reduce the gain of the position loop.
Third, two-axis linkage when the roundness of the overdifference
1. Axial deformation of the circle
This type of deformation may be caused by the machine is not well adjusted. Poor positioning accuracy of the axes or improper compensation of the screw gap will lead to roundness error when crossing the quadrant.
2. Inclined ellipse error (ellipse in 45 degree direction)
In this case, the position error value of each axis should be checked. If the error is too large, it can be eliminated by adjusting the position ring gain. Next, check that the interface board of the inverter or induction synchroniser is correctly set, and then check that the mechanical backlash of the gearbox is not too large and that the backlash compensation is appropriate.
