Friction welding is a solid-state welding process that joins materials through intense heat generated by friction. This technique involves rotating one workpiece against another, causing the generated heat to soften the materials at their interface, ultimately creating a strong, high-quality bond. Its reputation is built on versatility, adaptability to various materials, and efficiency. It is characterized by the production of reliable weld joints with minimal distortion, making it preferred in industries such as aerospace and automotive. Due to its robust, non-fusing nature, it is ideal for joining different materials and creating durable connections.

  • Friction Welding Process:
    Friction welding is based on the relative movement and plastic deformation generated by frictional heat under pressure and torque. This heat causes the contact surfaces in the vicinity to transition into a plastic state, inducing the appropriate macroscopic plastic deformation state. Subsequently, rapid forging under pressure completes the welding. Typically, friction welding is applied to rotating workpieces. Key parameters in controlling friction welding include rotational speed, welding time, forging pressure, friction time, and friction position accuracy. Position accuracy is a crucial factor in friction welding as it directly influences welding quality and strength.
  • Components of the Friction Welding Machine:
    The friction welding machine consists of the main machine (tool machine), the hydraulic system, and the control system. The main machine system mainly provides the required rotational speed, torque, and frictional pressure for the welding workpiece through the rotation device and the movement device, acting as the execution mechanism of the welding system. The main task of the hydraulic system is to supply hydraulic energy to various actuators of the welding machine and ensure proper lubrication of the main spindle rotation and the movement components of the sliding table. The control system is responsible for managing the required action sequence for the welding process and monitoring the execution of the components of the hydraulic system.
  • Inverter Control for Friction Welding:
    Our GD350 inverter is primarily used for the main spindle in the friction welding process. The requirements for inverter control are as follows:
    1. After each automatic welding cycle, the main spindle must return to the same position to ensure welding accuracy.
    2. The inverter must operate above the rated frequency, with a maximum operating frequency of 70Hz.
    3. The inverter should have robust overload capacity, with acceleration and deceleration times of 0.4 seconds for both positioning and general use. It should be able to withstand momentary overloads of up to 1.7 times.
  • Selected Inverter Model and Parameters:
 Voltage LevelModelQuantity
Inverter380VGD350-037G-41
Braking Resistor10 Ohm, 15 kW1
  • Control Diagram and Wiring Diagram:
    Control Sequence:
    1. The PLC sends a start signal; the servo motor drives the rotation device for rapid spinning.
    2. As the rotation device spins at high speed, the hydraulic system advances the sliding table forward, initiating the welding process gradually. Simultaneously, the sliding table advances, and the pressure gradually increases.
    3. Once welding is complete, the PLC sends a return signal to the main spindle. While the rotation device rapidly and precisely positions to zero, high-pressure forging is added to ensure a strong weld seam.
    4. After the inverter outputs the positioning signal, the pressure is maintained for a while, the sliding table automatically returns, and the next welding cycle begins. This process repeats.
  • Commissioning Instructions:
    The inverter uses speed control at the start of welding and pulse position control during positioning. To ensure accurate positioning, the parameters for position and speed must be correctly set.
    1. Check the wiring according to the electrical schematic.
    2. Enter the motor parameters for self-learning.
    3. Start with an idle test to check speed response and positioning accuracy. Adjust gains of speed and position loops, as well as acceleration and deceleration times, as necessary.
    4. After a successful idle test, perform a load test and adjust parameters based on actual performance.
  • Why Invt GD350 Series Inverter:

The GD350 inverter is a high-quality vector-engineering servo inverter with many I/O interfaces. It is characterized by a wide speed range, fast response times, and high control accuracy. Importantly, it has robust overload capacity (150% overload every 5 minutes, 1 minute allowed) and high control accuracy (maximum speed error of 0.1% in closed vector control). These features ensure flawless operation of the friction welding machine around the clock.

FREQUENCY INVERTER INSTALLATION

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