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TRAK Machine Tools
Southwestern Industries, Inc.
TRAK TRL Lathe, ProtoTRAK RLX CNC Safety, Installation, Maintenance, Service & Parts List
3.4.1 X & Z-Axis Measurements Do Not Repeat
With a dial indicator mounted to the spindle, touch off a fixed surface either in the X or Z-axis
direction and then set the DRO equal to 0. Crank away several inches and then 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.
Expected repeatability numbers should be 0.0005” 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 and Z-axis Gibs using the
X and Z-axis Gib adjustment procedures.
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. 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 & 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 Section 5.2.2.
