Quality Inspection of Grinding Wheels by 3D Measurement
Initial situation:
The production line of a grinding wheel manufacturer is intended to be equipped with an inline system for quality control, able to perform a 100% inspection. Until now, the products have been assessed merely on a random basis in a manual procedure, by means of equipment featuring tactile sensors.
Of course, this kind of quality monitoring takes quite a lot of time.
Particular Challenge:
For the assessment of rotating parts, numerous parameters have to be taken into consideration: Concentricity, radial run-out and axial run-out (i.e. wobble); furthermore thickness, diameter, planarity and the absence of surface defects had to be examined. It was clear that only a non-contact measurement is able to carry out an accurate inspection without decelerating the production process, as both lateral surfaces of the grinding wheels as well as the outer surface of the circumference are involved.
All these surfaces have to be detected and to be checked for presence of surface defects like incisions. Furthermore, the planarity of the lateral faces has to be verified, in order to avoid wobble.
QuellTech Solution:
The solution developed by QuellTech consists in a configuration of three Q6 Laser Line triangulation scanners.
Each of the lateral surfaces is assigned to its own scanner. In order to enable the thickness precisely to be determined, both laser lines are mutually oriented in opposite direction. The third scanner inspects the outer circumference of the wheel, this way measuring diameter and radial run-out. All of these scanners are subject to encoder signals supplied by the rotary axis and synchronously triggered, so possible defects on the wheel can precisely be localized. The measurement takes place at a resolution of ca. 30 µm, and a cloud comprising several millions of points is obtained.
The QuellTech 3D software solution checks the measuring data with respect to different tolerance ranges and presents the results in a display featuring all parameters required: Concentricity, radial and axial run-out, thickness, surface defects, together with the test result (OK/NOK). The results are sent to the PLC as well, in order to sort out defective items automatically.