Gecko tuning and System Measurement results
Gecko Tuning X-axis-
One of the reasons for my CNC adventure is to work with Scale and measurement data towards a goal of true closed-loop. I have done the initial mounting and testing on X-axis using a 1 micron Certified High Precision Scale. I’ll cover what was used for equipment in my testing and early results. System installed was a standard CNC retrofit kit supplied by Industrial Hobbies.
Scale- Foic Certified High Precision Glass Scale 0.001mm resolution +/-0.003mm deviation within 500mm travel, repeatability +/- 0.001mm the metric equivalent to 0.00004”
Gecko 320 Servo Card
¾” Precision Rolled Ballscrews specified at 0 to .003 +/- deviation per foot Encoder ballscrew shaft mounted with a 4 to 1 reduction
Industrial Hobby High Performance Servo motors
I was unable to measure any backlash from the double nut ballscrew at 0.001mm registration. Ball nuts are set at approximately 100lbs of torque as per IH specifications.
These are initial results while not definitive they are suggestive. Perhaps other group members will suggest other testing parameters.
Gecko 320 unit grossly tuned Damp and Gain were set in the 11 o’clock position. Testing done was with using current Mach 3 software. With these settings it became clear that system would not hold a repeatable Zero point. System was variable in repeatable accuracy and deviation showed increase in measurement deviation as table was operated in both directions multiple times.
In tuning I was able to get a consistent and repeatable Zero registered to within measurement system deviation specifications. While ballscrew deviation in length was only grossly tested; it did not exceed 0.0015” at any point.
Ken
Kenneth A. Emmert
SMW Precision LLC
Spokane, WA
866-533-9016 Toll Free