Daily Maintenance Methods for Hydraulic Presses.

Hydraulic press is mainly an upper piston hydraulic press, whose main working characteristic is that two parallel hydraulic presses form a downward vertical pressure on the bending beam to drive the bending of the mold. The goal of reducing the weight of structures to save energy in operation has long been pursued by people in industries such as automotive and aerospace, and is also one of the trends in the development of advanced manufacturing technology. Compared with traditional stamping processes, hydraulic forming technology has obvious technical and economic advantages in reducing weight, reducing the number of parts and molds, improving rigidity and strength, and reducing production costs, and has been increasingly used in industrial fields, especially in the automotive industry.

For hollow variable cross-section structural parts, the traditional manufacturing process is to first stamp two half pieces and then weld them into a whole, while hydraulic forming can form the entire hollow structure component in one piece along the section of the component with changes. This invention mainly controls the synchronous operation of the hydraulic press bending process and the positioning of the dead point of the hydraulic press when working at full load.

The downward rapid closing motion of the ordinary hydraulic press is mainly in the form of free fall, that is, the motion is generated by the weight of the hydraulic press crossbeam and its accessories. In this process, the rodless chamber of the hydraulic press is supplemented by an inflation valve, and the rod chamber will generate back pressure. The fast feed rate can reach 250mm/s, using open or closed loop control with proportional directional valve. The fast forward motion starts at the top dead center and ends at a bending plate 6 millimeters away, with a brief braking cycle. Different types of benders require different fast forward positions. The static position of the hydraulic press is the upper bending point of the top dead center. To prevent uncontrolled downward motion, the system uses a leak-free back pressure valve to close the rod chamber of the hydraulic press.

The stamping and bending stage of the hydraulic bending machine starts from the establishment of pressure in the rodless chamber. On the one hand, the stamping speed is limited by the oil supply of the oil pump; on the other hand, it can be adjusted by the proportional valve directional valve. At the same time, the reversing valve also controls the synchronous operation and the positioning of the lower dead point of the hydraulic press. Before repairing or cleaning the hydraulic press, the upper and lower molds should be aligned and the machine should be shut down until the work is completed. If it is necessary to start the machine or perform other operations, the mode should be manually selected and safety should be ensured. After one month of use of the pipe bending machine, check whether the bending parts of each pipe have deformed. If there are any abnormalities, they should be replaced. After two months of use of the pipe bending machine, all accessories should be tightened. During this work process, the machine should be shut down and the system should be without pressure.