Seam Bumps
Cross Section Double Seam Defects - Cause & Remedy

Seam Bumps are created from uneven distribution of lining compound and occur in seams from can bodies that are butt welded rather that lapped over and soldered. Tinplate weight reduction, can body spin flanging, reduced cut diameters of covers and Hot Filling are also contributors to Seam Bumps. Compound flows around during 2nd Operation seam cycle in front of the 2nd Operation Seaming Roll like a wave stopping in one spot when the Roll lifts away from the can.

Seam Bumps
Probable Cause Suggested Remedy
Body Hook too long. Reduce the Body Hook by decreasing the Lower Chuck Spring pressure
2nd Operation Seaming Roll Groove profile shaped incorrectly. Replace the 2nd Operation Seaming Roll with a Roll having a flatter or non-pear shape to move compound around more uniformly.