Most CNC machine tool manufacturers invest heavily in machine developments that improve accuracy but by using the latest calibration systems at its factory in Istanbul, Turkey, leading manufacturer Spinner has improved specified machine accuracies without the need to change designs. As Mr Nurhan, Technology Manager, explains, “The machine designs are no different but we have actually improved the accuracy, cut the support customers need by up to 90%, and have shown customers that we use the latest technology.”
Renishaw laser calibration - rotary axis compensation
Mr Nurhan explains one of the areas in which Spinner has seen most benefits from laser calibration, “We test and calibrate the rotary motion of every sub-spindle fitted to our turning centres because the encoder on the motor, although repeatable enough, does not position as well as we want. Some encoders are only accurate to 6 arc minutes but by using the Renishaw RX10 rotary calibrator unit, we can guarantee better than 1 arc second repeatability. This is done by testing the sub-spindle on the finished machine. Errors detected by the RX10 are corrected by adding compensation values generated by the RX10 software to registers in the controller. The sub-spindle is tested again to check the new positioning accuracy and provide a traceable calibration certificate, with options for formats according to various international standards.”
The RX10 is an accessory for Renishaw’s laser calibration systems, allowing the comparison of the programmed rotation of a drive or rotary table to the actual rotation as measured using a traceable laser source. This is done by mounting the RX10 on the rotary axis, then programming the rotary axis to rotate in defined steps. After each axis move, the RX10 unlocks, and rotates back to the previous position, re-locking on a highly repeatable Hirth coupling, accurate to 1 arc second. Angular optics are mounted on the RX10 and any angular error compared to the previous starting position is recorded. These error values are used for compensation
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment