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XYZ Machine Tools
ProTURN SLX 1630 ProtoTRAK SLX CNC Safety, Installation, Service & Parts List Manual
Test for accumulative error by moving the axis a number of times to see if the error
gradually grows by a small amount. If the error abruptly changes by a large amount it may
be caused by a bad encoder.
Expected repeatability numbers should be 0.01 mm or less.
Possible Cause
Check This
Machine Tool & Setup problem
Check for any looseness in the setup. See Machine Tool
& Setup Section 4.1.
X and Z-axis Gibs are loose
Check the adjustment of the X-axis Gib using the X-axis
Gib adjustment procedures. See section 5.2.1.
X and Z-axis Drive Trains are loose
Check Repeatability using the Repeatability and Positional
Accuracy procedure. Step by step, carefully inspect the
Drive Train for any looseness. It may be necessary to
disassemble and then reassemble the Drive Train. See
Mechanical Drive Train (X, Z) Section 4.2.
Encoder Disk or Reader Head on
motor are loose
Swap the motor in question with a known good motor.
For example, swap the X-axis motor with the Z-axis
motor. If the symptom stays with the motor in question,
then replace the motor. If not, then the motor is not at
fault and something else is causing the problem.
3.4.2 X and Z-Axis Measurements Are Not Accurate
Measurements repeat, but with a dial indicator mounted to the spindle, traversing the
length of a gage block or some other measurement standard, the measurement is
not accurate.
Note: If your part has incorrect dimensions, see Parts Have Incorrect Dimensions, Section
3.1.4.
Note: First check for repeatability of the DRO: With a dial indicator touch off a fixed surface
either in the X or Z-axis direction and set the DRO equal to 0. Crank away several inches and
touch off again at the same place. If the reading has not returned to 0 on the DRO, zero the
display and repeat the procedure. If the measurement does not repeat, you have a
repeatability problem that must be resolved before the accuracy problem can be resolved. See
Measurements That Do Not Repeat, Section 3.4.1.
Possible Cause
Do This
The Calibration is incorrect
Recalibrate the machine.
See Calibration & Backlash Constants
Incorrect backlash values
If the machine does not repeat bi-directionally check the
backlash on the axis in question. See Calibration and
Backlash Constant Section 5.2.2.
3.4.3 The DRO Is Not Counting
The DRO for one axis is not counting when an axis is moved. Often times if this is
the case the axis will fault. See section on faulting.
Do the following Service Codes:
Code 33
Software Identification. This is needed if you call Customer Service.
Code 100
Axis open loop test.
Used to check the maximum feedrate of an axis
and if the encoders are counting.
Code 132
Electronic handwheel test.
Code 131
Manual Encoder Test.
