The precision forging machine is a radial precision forging machine. It is a high-frequency precision forging equipment. It mainly uses an industrial control computer as the main control unit. It combines CNC technology and digital control technology. The encoder feedback values are subjected to analog-to-digital conversion and calculation. After the main control unit and the target program are compared and calculated, different commands are output to the hydraulic servo cylinder system, hydraulic servo motor rotation system, and pneumatic two-way motion mechanism to achieve the required execution of the target program. The movements are unified to form the entire closed-loop control system of the precision forging machine, which realizes the fully automated high-precision forging of the precision forging machine. The forging base is divided into two parts, the main body and the chuck. The main body includes a gear transmission box and a forging box. The gear transmission box is used to achieve the uniform distribution of the forging power of the 4 groups of large gears. The forging box is used to complete the workpiece. Uniform forging. The two sides of the main machine are equipped with chucks with large displacement and different lengths. The displacement value of the chuck is accurate. The feed speed can be adjusted quickly and in real time according to the forging rhythm of the main machine to complete the high-quality forging of the workpiece.
Chuck movement control principle
When the precision forging machine is working, a main motor drives 4 sets of mutually symmetrical hammer heads to forge the workpieces at high frequency. At the same time, the chucks on both sides of the host machine hold the workpieces and move back and forth according to a preset program to complete the workpieces. forging. Due to the diversity of the initial processing length of each batch of workpieces and the particularity of the workpiece material, for different diameter workpieces, different deformation amounts and feed rates must be set during different passes of forging to ensure the material of the workpiece after forging. Organizational performance consistency and stability. Therefore, in the control of the forging process of the precision forging machine, the axial reciprocating clamping movement of the chucks on both sides of the host has very strict control accuracy requirements, which must be guaranteed to be within 0.1mm. The real-time control system for the axial movement of the chuck of the precision forging machine is composed of a host computer, a CNC controller, a digital-to-analog conversion board, a hydraulic servo valve, a chuck hydraulic cylinder, and a magnetostrictive displacement sensor
. The displacement sensor is installed axially on the chuck. Outside the guide rail under the base, the chuck's axial movement is pushed by a servo hydraulic cylinder.
The displacement sensor detects the displacement value of the chuck in real time and sends it to the CNC controller as a feedback signal. After the CNC controller compares the target displacement value with the actual feedback displacement value, it outputs a digital control signal. The card converts digital signals into analog signals and outputs them to the hydraulic servo valve. The hydraulic servo valve adjusts the amount of hydraulic oil flow in the cavity in real time according to the size of the input signal, thereby driving the collet hydraulic cylinder to complete the entire collet shaft. To move. The high precision forging performance of the precision forging machine cannot be separated from the high precision of the axial movement of the chuck, and the high precision of the axial movement of the chuck necessarily requires that the displacement sensor as a feedback link also has accurate detection performance and characteristic parameters. According to the measurement principle of displacement sensors, common displacement sensors can be roughly divided into magnetostrictive, differential transformer, inductive, encoder, ultrasonic and resistive. Taking into account the complexities of electromagnetic interference at the industrial site, unstable temperature and humidity conditions, large site vibrations, and excessive oil dust, etc., especially the real-time and accurate detection requirements of the 5m and 7m long displacement values of the chucks on both sides of the precision forging machine, After comprehensive consideration, a magnetostrictive displacement sensor was selected as the core measurement element. There is no direct contact between the sensor's sensing element and the measurement medium, there is no wear after long-term use, and it has high linearity, hysteresis and repeatability, and high reliability. It is very suitable for the use environment of industrial forging sites, many advantages Completely superior to other types of displacement sensors, these strictly guarantee the real-time and stable detection of the displacement of the precision forging chuck.
Chuck displacement detection principle
The chuck displacement detection is realized by a magnetostrictive displacement sensor, which is divided into a waveguide, a circuit unit and a position magnet. The waveguide is protected by a flexible flexible outer tube and packaged into one body. It is installed axially in a stainless steel sleeve under the chuck bed; the circuit unit is fixed at the end of the chuck bed; the position magnet is installed in the precision forging chuck The lower part of the base moves axially back and forth along with the base of the collet. When the circuit unit at the end of the chuck applies a certain current excitation pulse to the waveguide, the current pulse propagates along the waveguide toward the forging host, accompanied by the generation of a circular magnetic field surrounding the waveguide, and at the same time, the position on the chuck substrate The magnet also generates a magnetic field parallel to the waveguide. According to the magnetostrictive effect, torsional strain pulses will be generated where the two magnetic fields meet. This strain pulse is propagated to the two ends of the waveguide at a fixed speed, and the unwanted waves propagating to the side of the host box are eliminated by the end damping, and The effective return pulse propagates into the circuit unit to participate in the calculation, thereby calculating the displacement of the position magnet. A magnetostrictive displacement sensor is used on the right chuck of the main machine of the precision forging machine, which fully meets the real-time requirements for accuracy detection when the chuck moves in two directions.
The application of the magnetostrictive displacement sensor
in the displacement detection of the precision forging machine chuck guarantees the high precision and reliability of the equipment operation, saves a lot of valuable maintenance time and maintenance costs, and accelerates the pace of digestion, absorption and transformation of imported equipment technology , To facilitate subsequent equipment management and maintenance work.
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