What are the requirements for blanks in metal spinning

During the spinning process, the defects inside and on the surface of the blank will be enlarged, so the following requirements are imposed on the blank for Metal Spinning Machine.
(1) Spinning requirements for the inner and outer layers of the blank
① There should be no interlayers, inclusions, cracks and porosity inside the blank, otherwise, the spinning parts are prone to fractures, internal cracks and micro-cracks. Therefore, some large blanks and blanks with welded seams should be inspected for flaw detection.
② The surface of the blank shall not have defects such as spots, processing marks, cracks and burrs, otherwise, the surface of the spinning part will be scaly. In the case of a large amount of deformation, fracture will also occur.
③ The dirt and scale on the surface of the blank should be removed to avoid damage to the workpiece and contamination of the lubricant.

(2) Spinning requirements for dimensional accuracy of blanks
① Influence of blank wall thickness deviation: For cylindrical parts spinning, due to the excessive variation of blank wall thickness, the straightness of the spinning parts will be affected, and even bending will occur. For conical and curvilinear parts, prefabricated
The wall thickness deviation of the blank will make the spinning process unable to strictly follow the sine law, resulting in a decrease in the internal and external precision of the spinning part, and an increase in the wall thickness deviation. Therefore, the wall thickness deviation of the blank should usually be less than 0.1mm.
②Inner diameter deviation of blank: If the deviation of inner diameter of blank is too large, it is easy to cause the ovality and diameter expansion of the spinning part.
③ The ovality of the prefabricated blank and the non-axiality of different parts of the blank.
④ The bottom of the blank is not perpendicular to its axis.
⑤ The gap between the blank and its core mold.
(3) The requirements of spinning on the uniformity of the material properties of the blank. The uneven metallographic structure and stress distribution of the blank will cause uneven deformation of the blank in the spinning part, which will cause the spinning part to bulge or break, and make different parts of the blank. material
Material strength is not the same. In addition, the dimensional accuracy of the spun parts will decrease and the ovality will increase.