Linear Positioning Laser Calibration Setup
Laser Calibration of your precision machine tool will give you the knowledge that at least hole locations will be correct. However, if precision machining is to take place, machine tool geometry should be evaluated and adjusted.
Machine Tool Laser Calibration (Pitch Error Compensation) and Backlash Compensation is a simple and straightforward process only a few things need to be taken into consideration.
1. Machine Tool Geometry is within tolerance i.e.,
machine is level, gibs are tight, axes are square
to each other, etc.
2. Backlash of the axes is minimal.
3. Control has the compensation program option
installed.
4. Machine Control Parameters have been set up
correctly.
All Laser Calibrator Systems monitor the material temperature and the air density; this takes into consideration machine thermal growth and laser beam frequency.
For efficient setup of the laser system some guards may need to be removed. (mostly for ease of access to the optics).
Step one of the setup is to "find" the stroke limits of the axis. The material temperature sensors and the air sensor should be brought out in the very beginning to allow for stabilization. The laser optics are setup in line on one end of the machine stroke. (almost touching) Then the laser head is then brought into correct alignment. Step two is to move the machine axis to the other extreme, the laser head is now aligned (far), using rotation and elevation adjustments. Finally the machine is moved to the start position (near) and final alignment is verified. Depending on the machine and the laser system operator, only a couple of adjustments need to be made at the end of each stroke. After all laser optic alignment adjustments are made, data recording takes place. The stroke of the machine, and the machine compensation interval dictate the amount of data required for each axis. The dwell at each point is dependent on the stability of the setup. These factors determine the amount of time required for a through compensation (calibration) of the Linear Positioning Accuracy.
Measurement & Machine Technology, 27729 Bohn, Roseville, MI 48066. Tel: 313-530-5083; Fax: 810-775-5766.