Foreign object strike detection

Issue

Defects occur due to small scrap strike marks in the plate drawing process

• Defects are caused by hammering in scrap as small as 1 to 2 mm.
• Detection is done by image inspection and the bottom dead center sensor, but 100% detection is not possible.
• Labor costs are high due to the possibility of defective products leaking out, as all inspections are conducted.

Solution

Two bolts for fixing the die were replaced with the piezoelectric load sensor "PiezoBolt" to monitor load fluctuations.

As a result, it was found that there was a difference in the load applied to the left and right bolts (eccentricity) when scrap was sandwiched between them. By creating a system that can detect the same regardless of the size of the scrap and by determining a threshold value and creating an alarm to alert the operator if a defect occurs, we were able to identify defective products caught between the scraps and eliminate all inspections.

Result

Eliminate all inspections by detecting the launch of foreign objects

• It is now possible to detect when impurities such as burrs and scrap are introduced.
• By quantifying eccentricity conditions, the frequency of burr generation can be improved and detection can be made before burrs affect quality.
• Reliable detection of foreign object strikes eliminates the need for a full inspection.