The TDF Flange forming machine is also called flangeless duct. Compared with the traditional rectangular duct, its manufacturing speed is faster and more convenient, and it also has a smaller air leakage rate. Its advantages are to save materials and reduce project investment; the amount of air leakage is small, energy consumption is reduced, and operating costs are saved. It is quite popular with construction companies.

①Single flat bite: used for the splicing seam of the plate and the longitudinal joint seam of the air duct;
②Single bite: used for circular elbows, back and forth bends and transverse seams of air ducts;

③Single-angle bite: used for the longitudinal joints of rectangular ducts or components, as well as the corners of rectangular elbows and tees;
④Joint angle bite: the use is the same as the third method;

⑤Double flat bite and double bite: the same as the first and second methods, because this method is complicated and cumbersome, it is not used much.