The sealing of metal cans refers to the process in which the flanging of the can body and the round edge of the can lid are rolled and sealed in the sealing machine, so that the can body and the can lid are rolled up with each other and pressed to form a tightly overlapping curling edge. The resulting bead is called a double bead. The double edge sealing machine completes the sealing of cans mainly by the indenter, the head roller of the pallet and the large part of the secondary roller, and the sealing of the metal is completed under the synergy of the four major components.
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Detection of double curling
In production, the good sealing of the curling is ensured by the regular inspection of the first and second curling edges. The main tools are: a beading projector or a beading caliper and a beading gauge for the canning industry.
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Items tested include:
(1) External inspection of the hemming: Visual inspection and measurement inspection The appearance requirements of the hemming: the upper part of the hemming is flat, the lower edge is smooth, the entire contour curve of the hemming is moderately curled, the width of the hemming is consistent, and there is no incomplete curling ( Sliding seal), false seal (false roll), large slump, sharp edge, quick mouth, teeth, iron tongue, crimping broken, double line, jump seal and other defects caused by the failure of the indenter or roller. Carry out the measurement of can height, curling thickness, curling width, countersinking degree, and sagging lip degree.

(2) Internal inspection: Visual inspection: Observe the internal gap of the curling on the display screen of the projector or with the aid of a magnifying glass, including the top gap, upper gap and lower gap, observe the occlusion status of the can body hook and lid hook and the lid Hooked pattern case. Measurement and testing: Determination of can body hooks, lid hooks, overlapping length (LOL) and overlapping rate (LOL%).
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(3) Withstand pressure test: Use an empty tank pressure tester to check whether there is leakage. Pressure resistance requirements for crimping: Generally, small and medium-sized round cans are subjected to a pressure test with a gauge pressure of 98kPa, requiring no air leakage for 2 minutes. Large round cans are subjected to a pressure test with a gauge pressure of 70kPa to maintain no air leakage for more than 2 minutes.
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Most of the production lines of two-piece cans, three-piece cans, easy-open caps, crown caps, plastic bottle caps, etc. in China are imported from Europe and the United States and other countries. Mold accessories and equipment spare parts also rely on imports, with high prices, long lead times, The service lag increases the production cost of the enterprise.
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At present, most of the advanced filling production lines in my country are imported from Europe and the United States. After the installation and debugging are completed, the detailed drawings of the parts are rarely left.

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