Judging the quality
of the double seam formed by the Can Seamer is done by
both visually inspecting the
torn down seam profile as well as measuring the
various dimensions. Variations owing to differences in
tinplate thickness, temper and sealing compound weight
are acceptable within prescribed limits.
FIRST OPERATION
SEAM FORMATION
Tight 1st
Operation Loose 1st Operation
1. The
first operation seaming roller curls the cover under
the body flange to form a hook.
2. The seam should be rounded at
the bottom and in contact with the body of the
can.
3. If the seam is too tight, the bottom of the seam will be
slightly flattened through it's length.
4. If the seam is too loose, the
cover hook will not make contact with the can
body
SECOND OPERATION
SEAM FORMATION
1. The second operation seaming roller flattens the
seam thus locking the hook formed by the first operation
roller. The pressing also causes the compound to
compress and fill up the gaps in the seam not occupied
by metal.
2. Excessive pressure may produce
a defective seam since the extreme tightness
will stretch the material and cause an increase
in the width and outside diameter
of the can resulting in leakage.This tightness could also produce slippage
between the body and cover hooks, commonly called
'unhooking'. 3. Insufficient pressure will result in improper pressing
and locking of the seam, causing leakage.
