Automated Thread measurement enhances the AVR300 vision system from Optimax
Starrett’s AVR300 CNC vision measuring system can now measure screw threads with the optional MetLogix M3 Thread Module extending the AVR300 to threaded parts, including threads too wide for a single view. Workshops already using an AVR300 for profile and feature measurement can inspect threaded parts on the same machine, without separate thread gauges.
The AVR300
The AVR300 is a bench-top, vertical CNC video system with 300 x 200 x 200 mm of X-Y-Z travel. Scales resolve position to 0.1 µm, and X-Y accuracy is E2 = 1.9 µm + 5L/1000. It has 6.5:1 zoom optics, with a 12:1 zoom or interchangeable telecentric lenses as options, with LED surface and transmitted lighting. It runs MetLogix M3 software on a touchscreen PC. Providing video edge detection, 2D geometric constructs, and field-of-view measurement integrated with stage motion, the system is also touch probe compatible.
What the thread module adds
With the module installed, the operator picks the thread tool in M3, then clicks a point on the thread edge or drags along it. The software works out the thread form and reports:
- Outside (major) diameter, Root (minor) diameter, Pitch diameter, Lead and Root and crest truncation
M3 software then identifies the thread size and pitch, and results can be checked against metric and unified thread forms. Tolerance classes and annotation can be added to the result. Because it is part of M3, thread results sit alongside the rest of the inspection, in the same routine and report as the other dimensions on the part.
Threads wider than the field of view
At higher magnification, a thread can be wider than the camera view. The AVR300 manages this with its stage. The operator moves it to one side of the thread and marks the thread form there, then moves to the opposite side and marks it again. The scales record exactly how far the stage has travelled between the two positions, so M3 can calculate diameter and pitch from the two sides together. The result comes from the measured stage travel, not from how much of the thread fits on the screen.
The M3 Thread Module is available now as an option for the AVR300. For more information, contact Optimax
