There are a few typical measurements that companies do for double seam.
In order to measure, it’s important to take one can per seamer head off the line. There are a few ways to identify which can comes from which head, depending on the Seamer manufacturer. In some cases, the seamer has to be stopped, but many companies offer identifiers to make this unnecessary.
External gauges (at the beginning)
Cross section cutting (visual inspection)
Once the external gauges have measured, typically the can is cut either once or 3 times (at 120 degree angles) in order to create a cross section of the seam. The seam is then inspected and measured using a seam inspection software SEAMetal and SEAMscan.
In addition to the seam shape being verified as OK, the actual values of the seam need to be within the standard specifications. If the seam is out of specs, the seamer head should be set up once again.
Critical checks for the Double Seam:
- Proper overlap
- No Sharpness at the edge of the seam
- No Sharpness near the upper part of the Countersink
- No curl near the cut of the cover hook
- Correct Seam Thickness (not too tight, not too loose)
- Seam gap not too loose
- Measurement of External dimensions should be within the specifications
- Measurement of Internal dimensions should be within the specifications