High-speed and stable running of the main machine The running stability and the rotation speed of the tube molds are the key factors affecting the quality of the product. Therefore, the requirement of stability in the running of the main machine is very high. In high-speed operation, the smaller the radial run-out of the tube molds is, the more uniform the wall thickness of cylinder liner will be, and also the more stable the structure performance will be. The main machine is of cantilever construction with bearing blocks made of cast iron for good shock absorption. The stepless VVVF AC motor and high-performance vector control converter are adopted to drive the spindle rotating via high-performance V-shaped belt, thus to ensure accurate speed regulation of mould. The spindle is also provided with a brake that can ensure rapid stop of mould so as to enhance production efficiency. Rotary workbench with rapid, smooth and accurate positioning function The main multiple machines are arranged on the workbench that can realize multi-position shifting of each machine. The AC servo control is adopted for rapid and smooth rotation, accurate positioning and rotating speed regulation. The spray rod movement adopts servo control, which can stabilize the rod moving and make the rod positions adjustable, thus ensuring the uniformity of the coatings. The moving speed of the spraying rod can be divided into three adjustable phases, each of which can be adjusted in moving distance and moving speed to cooperate with the rotation speed of the tube molds and the spraying pressure to meet the requirements of a variety of complex spraying processes.