Single flat seam: It is used for the splicing seam of the board and the longitudinal closing seam of the round air duct, as well as the seam of the product that does not require high tightness.Single vertical bite: used for the circular joints at the ends of round air ducts, such as circular elbows and circular back and forth bends between the joints of each pipe segment.Corner bite: used for longitudinal seams of rectangular air ducts and fittings, corner seams of rectangular pipes and tees.Combined corner bite: also called corner bite, the bite seam is on the corner of the rectangular pipe, and the purpose is the same as the corner bite. It is more suitable for the corner seam connection of curved rectangular pipes.Snap Seam: Corner closure seam for rectangular duct and fittings. One side of the plate is processed into a socket with a convex buckle, and the other side of the plate is processed into a socket with a barb shape on the folded edge. When installing, insert the socket into the socket to form a seam: this kind of bite It is characterized by tight bite and reliable operation.At present, most of the bites are machined.