The reason:
(1) Short cooling time.
(2) Poor contact of cooling plate.
(3) Because the silica gel pad is heated, the edge part melts.
(4) Longitudinal heat sealing force is uneven.
(5) The edge of the heat sealing knife is irregular and blunt.
Countermeasures:
(1) Adjust the cooling time.
(2) Adjust the cooling plate.
(3) Replace or adjust the heat sealing knife.
(4) To prevent the edge melting caused by overheating of the silica gel pad.
