TDC flange is currently the most widely used one duct flanges. It has the advantages of time saving, material saving, high work efficiency, good sealing, durable and connecting structure. It is especially suitable for duct to duct with a large sectional area. TDC flange machine is composed of feeding frame, cold rolling forming machine and a cutting part. The cutting part can be divided into the grinding wheel cutting and non-stop cutting system, cutting system can be realized without stopping the cut-to-length. Cutting burr of small, can realize the full automation of production. The working speed of 6m/min. According to the working performance and the strength of flange and sealing level can be divided into five types: T-20, T-25, T-30, T-35, T-40, the corresponding connection corner is T-20DC, T-25DC, T-30DC, T-30DC and T-40DC.