Pipe bending machines are widely used in sectors such as shipbuilding, boiler manufacturing, the chemical industry, aerospace, metal structure fabrication, equipment installation, and mechanical manufacturing. There are various types of pipe bending machines; they can be classified by bending method (e.g., press bending, rotary draw/wrap bending, and compression bending) or by drive mechanism (e.g., mechanical drive and hydraulic drive). Depending on user requirements, these machines can bend various types of pipes—including those requiring planar or 3D configurations, as well as large or small bending radii. Regarding the working principle of hydraulic pipe bending machines: high-pressure oil from an electric pump is delivered via high-pressure hoses to the working cylinder; this oil drives the internal plunger to generate thrust, which then actuates the bending components to bend the pipe.

The key advantages include: 1. Use of a touchscreen and CNC module for conversational operation, making program setup simple and easy; 2. A stable machine bed structure that resists deformation; 3. Ability to set 16 bending angles per sequence, with memory storage for 16 program groups; 4. Slow-speed positioning functionality ensuring stable bending angles and a repeatability accuracy of ±0.1°; 5. On-screen error messages to assist operators in immediate troubleshooting; and 6. Proprietary coordinate-to-bending-value conversion software available for desktop computers to facilitate editing and calculations.

Of course, there are also disadvantages. In early hydraulic pipe bending machine designs, the hydraulic system was powered by an 11 kW motor driving a 25 mL displacement pump, typically operating at a system pressure of 16 MPa. The clamping, guiding, and mandrel cylinders operated independently, controlled by separate solenoid directional valves. During the bending process, the main bending cylinder and the follower cylinder operated simultaneously, meaning their respective directional valves were energized at the same time. Although throttle valves could be used to adjust the follower cylinder's speed to match that of the main cylinder, the issue of mutual pressure interference could not be eliminated. Furthermore, the directional control valves originally used for the clamping and guide cylinders featured an "O-type" spool configuration; this resulted in poor pressure-holding performance, leading to defective parts caused by the pipe slipping during the bending process.

After extensive research and development by the experts at Huameng Machinery, we optimized the hydraulic system schematic of the pipe bending machine. We replaced the original single-pump setup with a dual-pump system, utilizing a tandem pump (with displacements of 25 mL and 10 mL) to supply the system. The larger pump supplies the main bending cylinder, with pressure regulated by a modular relief valve (12); system unloading is achieved via the neutral position of the directional control valve during pump start-stop cycles. The smaller pump supplies the auxiliary cylinders, with an electromagnetic relief valve (7) at the outlet handling both pressure regulation and unloading. We replaced the directional control valves for the clamping and guide cylinders with "Y-type" spool valves (9) and added pilot-operated check valves (10) to ensure reliable pressure retention, significantly improving performance. As the main cylinder and auxiliary cylinder circuits operate independently, the machine can bend pipes of various specifications simply by adjusting the speed of the follower cylinder to match that of the main bending cylinder.

Zhangjiagang Huameng Machinery Technology Co., Ltd. specializes in the manufacture of pipe bending machines, including CNC, hydraulic, and fully automatic models. Adhering to the business philosophy of "Customer First, Integrity-Based," we sincerely welcome new and existing clients to visit us; our entire team is dedicated to providing you with comprehensive service.