The flange connection is a detachable connection. The flange is provided with holes and can be threaded with bolts to make the two flanges tightly connected, and the flanges are sealed with gaskets. According to the connected components can be divided into vessel flange and pipe flange. When manufacturing flanges in the design scheme, we need to carry out production and manufacturing from many aspects, such as tooling design scheme, performance regulation, bending stiffness calibration, milling production and processing, tooling structure, etc. Flange design scheme Production and manufacturing 1. Tooling design scheme Production and manufacturing Large and medium-sized flanges are formed by welding two clamping base plates 900 with each other, two flange support plates, two vertical plates and four rib plates. In order to ensure the bending rigidity of the tooling, the welding of the connecting plate shall be made with groove penetration, and the welding angle shall be 20-30mm high. Drill opposite bolt holes on the flange support plate to ensure that the flange can be accurately connected with the flange support plate by bolts. Leave a gap between the reverse side of the small end flange and the middle of the support plate that can be put into the small and medium-sized manual hydraulic jack. In addition, provide vacancies on the flange support plate along the vertical plate orientation to facilitate the bending pipe to be installed into the tooling. Choose carbon steel plate to make tooling similar to groove structure, and consider the rigidity requirements during drilling. 2. Tooling performance stipulates that the two flange surfaces of the large and medium-sized flanges are vertical to each other, while the operation table of the numerical control vertical lathe rotates horizontally. Therefore, the key function of the tooling is to connect the tooling with the flange by using the bolt holes on the large-end flange. When the tooling is clamped on the working table, it is necessary to ensure that the flange plan to be produced and processed is in the same boat and parallel to the CNC vertical lathe operating table. In order to reduce the total number of tooling, the tooling should be able to change the clamping part to ensure that the flange at the second end of the elbow can be produced and processed in one tooling. In addition, the tooling must have sufficient bending stiffness, otherwise it will seriously endanger the production and processing quality of flange sealing ring groove. Therefore, under the consideration of application conditions, the aspect ratio of the tooling should be reduced as much as possible, which can improve the bending stiffness and is beneficial to actual operation. After the tooling and large and medium-sized flanges are fixed, the radius of gyration cannot exceed the middle and half of the work of the lathe, and can be easily clamped, adjusted, and drilled.