The hermetic seal formed between the can body and the can end is referred to as the double seam. The body flange and the curl of the end interlock during the double seaming operation to form a strong mechanical structure.
A good double seam formed by the can seamer is essential for assuring that there is no product leakage or contamination.
The double seam is formed with two seaming rolls, a first operation and a second operation. These seaming rolls are equipped with specific forming shapes known as seaming roll profiles which are varied in design relative to the can end seaming panel specification and material thickness being closed.
Two identifiable seals are provided within the double seam. The first roll approaches the can lid, and rolls up the lid curl and body flange sections of the can before retreating. Next, the second roll approaches to compress the rolled-up sections to end the seaming. In other words, the 1st roll rolls up the can lid and can body, doing mainly the bending work, while the 2nd roll compresses the rolled-up sections, and
During the double seaming operation, considerable pressure is exerted on the can end, the can body and the sealing compound. The compound should be enclosed by the double seam. Sealing compound is rubber-based gasket or sealing material that apply into the annular groove of the can ends.
The efficiency of the seam depends on the mechanical perfection of the two interlocking hooks formed during the seaming operation, plus the presence of a thin film of lining compound.
Can seaming
