Large-end machining was traditionally done using hot forging forming technology, requiring high-power, heavy-duty presses and corresponding upper and lower forging dies. Manufacturing a large-end forging die is expensive, with a long production cycle, weighing dozens of tons, necessitating heavy-duty crane lifting equipment, and is not easy to transport. Additionally, its utilization rate is low, thus making the processing cost of large ends quite high. Clearly, this is one of the main drawbacks of hot forging for manufacturing large, medium-thickness ends. For medium-thickness ends, within the equipment's manufacturing capabilities, various shapes such as elliptical, dish-shaped, and more, do not require forging dies, which can reduce costs and overcome the drawbacks of hot forging. Therefore, their processing costs are lower than those of hot forging, which is one of their main advantages. The aforementioned large-end was formed using a hot spinning machine. The following is an introduction to its forming process.

Large-end hot forming process includes large-end spinning forming, which is differentiated by forming temperature and includes cold spinning (room temperature), warm spinning (<120℃), and hot spinning (>800℃). Since the 1970s, cold spinning forming has gradually expanded its use domestically, but it is only suitable for large ends with plate thicknesses of 30mm or less. Large ends thicker than 30mm are difficult to form and require hot forging or hot spinning forming processes.