In manufacturing industry today, and particularly in the automotive sector, assemblies - such as doors, hood lids and tailgate lids - are clinched instead of welded. This clinching process is mainly used for aluminium parts, but it is also useful for joining sheet metal parts and profiles of varying thickness and materials.
In contrast to riveting, localised cold forming without ancillary fastening components produces non-detachable bonds. Importantly, the force necessary for plastic deformation can be used for process monitoring.
Force monitoring can detect the following:
- Dimensional deviations or an incorrect number of sheet metal parts
- Wear of the clinching tool
- Process faults such as punch or swage breakage
- Incorrect setting of the press height
- Insufficient bottom thickness
Permanent monitoring of the clinching force cycle using piezoelectric measuring technology from Kistler not only makes the process cycle transparent, but also monitors the long-term stability of a clinching machine. Clinching tongs can therefore be periodically checked with the calibration transmitter Type 9831C322. The parameters are documented and, if necessary, readjusted. A calibration transmitter can also calibrate sensors for indirect or direct force measurement in the machine.
Pop riveting or blind riveting can also be monitored and documented by integrating piezoelectric force sensor technology and visualisation by means of the CoMo Net Type 5863A1... or CoMo View Type 5863A2... process monitoring systems.
Force monitoring of clinching and riveting prevents faulty components from entering volume manufacture, thereby ensuring consistently high product quality. At the same time, production costs are reduced, since there is no need for subsequent manual rejection of deficient clinched or riveted joints.