COMMON SEAMING PROBLEMS

A good double seam formed by the Seamer is essential in assuring that there is no product leakage or contamination. A well maintained seamer with proper settings routinely checked will consistently produce accurate seam results.

Seam inspection is done in two ways, externally (non-destructive) and internally (destructive).

For external inspection, the seam is visually checked for any irregularities or deformities. The Seam Width, Thickness and Countersink Depth are also checked and measured.

Internal inspection requires the vertical cutting of the seam for viewing on a profile projector. The seam is visually checked and dimensions for the Body Hook, Cover Hook, Tightness and Overlap are measured.

Final double seam


	Tightness (Wrinkle) Rating Double seam tightness is graded in percentages. The ideal tightness for most cans is between 80-100%. Lower ratings will cause wrinkling resulting in leakage. The most common reasons for this are: 1. Low 2nd operation seaming pressure. 2. Incorrect 2nd operation seam profile. 3. Excessive sealing compound.

Probable Causes
	Long Body Hooks •Excessive base (lifter) plate pressure •Mushroomed can flange
	Long Cover Hooks •Excessive 1st operation seaming pressure
At body overlap	Cut Seam (Fracture) •Seam too tight •Excess welding at overlap •Excess sealing compound •Long Body Hook

Probable Causes
	Short Body Hooks •Low base (lifter) plate pressure •Excessive 1st operation seaming pressure •Insufficient 2nd operation seaming pressure •Defective can flange
	Short Cover Hooks •Insufficient 1st operation seaming pressure •Excessive base (lifter) plate pressure •Defective or worn out seaming rollers •Excessive countersink depth
	False Seam •Mushroomed can flange •Bent or damaged can flange •Bent or damaged cover assembly •Incorrect can and end (lid) assembly or alignment •Filled product extending over can flange