Blanking lofting adopts parallel line method, that is, the whole circular tube is divided into several parallel lines for calculation lofting. The output data is different according to different blanking methods. If the blank is selected, the unfolded length and the intersecting length are calculated with the center of the blank as the diameter, and the operator can draw lines on the blank directly according to the unfolded drawing and related data. If the finished pipe is selected for blanking, the diameter is calculated by the outer diameter of the circular pipe plus the thickness of the sample material, and the sample is loaded and unloaded according to the relevant data, and then the sample is wrapped outside the finished pipe for blanking. Please refer to the deployment diagram for details, as follows:
(1), draw a straight line segment with the length equal to s, and divide the line segment into n equal parts, each with the length equal to m;
(2) Draw the vertical line of the line segment downward through each bisector, and measure the heights of HA (1) ~ HA (n/4+ 1) and HD (1) ~ HD (n/4+ 1) on the vertical line of each bisector in turn according to the figure.
(3) According to the drawing, take the line n/4+ 1 as the turning point, and connect the measured points with a smooth curve, that is, the branch expansion diagram.
The quality of extended data communication is determined by processing technology and raw materials. Usually can be divided into the following categories:
(1) The seamless tee is the best quality tee, but the porcelain tee is also divided into two grades. There are two processing technologies of seamless tee, one is hot-pressing tee, which is the earliest technology. This tee is formed by hot working, but the cost is also the highest, especially the seamless tee with equal diameter is the most difficult to produce.
② The raw material of cold-drawn tee produced by seamless pipe is seamless pipe, and the price is lower than that of seamless pipe.
(3) It is a carbon steel tee with joint. The cost of this tee is relatively low. As the name implies, the processing method of this tee is to slowly draw a hole on the round pipe and then weld the branch pipe, and smooth the weld to get the finished product. The price of this tee is about half of the cost of a cold-drawn seamless tee, so many unscrupulous manufacturers often use this tee to deceive customers.
④ The simplest processing technology is to directly weld the branch pipe by opening a hole in the pipeline, which is called welded tee. At present, this tee is only used for water heating and occasions where large diameter is not easy to process.