1 Introduction At present, in the oil pump nozzle industry, the traditional nozzle processing mostly depends on the manual operation determined by individual skills, the product quality is unstable, the production efficiency is low, the labor intensity is large, and the waste product rate is high. This system is designed for an EDM machine and adopts the negative electrode discharge method that uses brass to discharge the workpiece to achieve the purpose of processing. Through the test, the ratio of brass to workpiece was deducted, and the depth of machining required by the program was controlled. The socket of the nozzle was completely in accordance with the requirements, which improved the machining speed and ensured the machining accuracy. It completely replaced the traditional wind-milling process. 2 design ideas According to the processing technology of the nozzle and the parameters of the processing workpiece, the stepper motor drives the electrode to move, it is necessary to accurately and automatically sample in real time, and the working frequency of the stepping motor is changed to control the feeding amount of the stepping motor, in order to meet the nozzle surface Requirements, in the process of processing, according to the ratio of wear and tear obtained by the test, using the look-up table programming method to perform real-time correction of the electrode, which is controlled by the grinding wheel motor. According to the machining depth of different blank workpieces, the corresponding frequency and the number of steps to control the operation are taken. The process sequence control logic includes: (1) Fast forward: In order to improve work efficiency, after the workpiece is installed, the stepper motor must quickly move to the surface of the workpiece being machined. We use a three-phase stepping motor (45BF3) as the electrode's feed drive component. The controlled stepping motor has three basic working modes of positive rotation (feeding), reversing (retraction) and stopping, and the positive and negative rotations also have different operating frequencies (ie, feed or retract speed). Feeding and retracting speeds are adjusted according to the software. When the three-phase winding of the stepping motor is electrified in the order of A→AB→B→BC→C→CA→A, positive rotation can be achieved, whereas if A→AC→C→BC→B→AB→A is selected In order to achieve the reversal, if the output state remains the same, the motor will stop running. Use the P1 port of the 8031 ​​P1.0, P1.1, P1.2 to control the three-phase winding of the motor. Control how it operates. In the process of processing, at the same time to control the processing voltage, switching discharge capacitance, when repairing processing electrodes, to switch the voltage of the workpiece, the motor. These are the software to control the opening and closing of each relay according to certain timing. 3 system hardware design This system hardware is made up of four parts, namely the basic system composed of 8031 ​​single-chip computer, 2764 EPROM and 74LS373, drive circuit, sampling circuit and display and keyboard scanning circuit. Here mainly introduces the basic system and drive circuit. 3.1 Basic System The system has set up a 5-digit display and 7 buttons. The display shows the processing mode status, setting value, and machining residuals respectively. The seven keys are: start, reset, pause, ten position digit, position digit, set number function keys. , Processing mode selection, when the home button function, can give ten and a few number, processing mode selection can choose rough grinding, rough grinding process. In the software, the processing volume of 1 to 99 filaments is converted into corresponding data according to a certain conversion relationship and stored in a table. In the processing, the data in the corresponding table can be taken according to different processing amounts. Use a serial input, parallel output shift register 74LSl64 to connect the LED display and keyboard. System schematic shown in Figure 1. 3.2 Drive Circuit Drive circuit diagram shown in Figure 2. The program controls 8031P1 output data, and the stepper motor is forwarded and reversed by the 74LS07 driver. Taking into account the interference caused by high-low frequency radiation and on-site power grid fluctuation during the processing of the system, optical isolation is adopted, as shown in Fig.2. When P1.0 output is high level, the first pin of 74LS07 output is low level, at this time, the optocoupler diode is turned on, the light triode is also turned on, and the triode T is also turned on, so that the winding is stimulated by 24V, and vice versa. Optical isolation, the winding is not voltage excited. Diode D1 plays a protective role The light-emitting diode D2 indicates the working state of each phase of the motor, and also brings convenience for maintenance. The other bits of the P1 port can also be controlled by a program. The 74LS373 can also be used as a relay control or for later expansion control. 4 System Software Block Diagram Block diagram shown in Figure 3, after the system power-on reset, start the program from the 8000H unit. First, the system is initialized, then the display call, key scan and key processing are performed. After the number key is pressed, the corresponding number of processing steps can be set for the ten-digit and one-digit adjustment. After the start key is pressed, the system starts the timer interrupt and enters the processing state. After the processing is completed, the status is displayed and the tool is retracted. The electrode is returned. Into the spot. According to the stepper motor forward and reverse control state, determine the corresponding control word, and then stored in a table, in the program according to the state of processing to take the corresponding control word output. Stepping motor step progress is also based on the stepper motor stepping equivalent and electrode wear system to determine the corresponding control parameters, the 1 - 99 wire control number is stored in a table, corresponding to the table in the processing Units are compared. The speed of the stepper motor can be adjusted by changing the timing constant. In the process of designing the software, automatic interference protection measures have also been added. When the program is running, the 8031's timer tracking program is used. When the program is normal, the timer is continuously reset. If the program is faulty due to interference, the timer can return the program to the error point and the program can continue to run. 5 Conclusion The system has been put into use at an oil pump factory. Practice shows that the system has reliable performance and convenient operation, which brings obvious economic benefits to the company. references: [1] Zhang Youde, Zhao Zhiying, Tu Shiliang. Microcontroller microcomputer principle, application and experiment [M]. Shanghai: Fudan University Press, 2001 1: Low speed electric truck, pickup truck, minivan
4: Mainly used for short distance cargo transportation, city express delivery, suitable for small-scale logistics
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(2) Quick return: After processing the preset machining amount, the stepping motor must be returned to the initial position.
(3) Coarse grinding: For the rough machining of large-size blanks, in order to improve work efficiency, you can choose to perform rough machining separately. During rough machining, the stepping motor feeds at the rough grinding speed, and at the same time, the discharge voltage is switched and the discharge capacitance is switched to control. Spark discharge, fast discharge, increase processing speed.
(4) Fine grinding: When the processing size is small, in order to ensure the angle and smoothness of the seat surface, the method of fine grinding is adopted. When the grinding is fine, the discharge spark is small and the processing voltage is low. This is also the switching of processing voltage and discharge through the software control relay. Capacitor implementation.
(5) Rough grinding: This system can perform rough grinding process once. At the beginning of processing, rough grinding is used. When machining within a certain range (eg, 3 wires), the system automatically converts to machining, which not only improves the machining speed but also ensures the accuracy and finish. The system can control the amount of spark discharge in both processing modes. 
[2] He Limin. SCM application system design [M]. Beijing: Beijing University of Aeronautics and Astronautics Press, 1991
[3] Chen Li. Stepper motor and its application [M]. Shanghai: Shanghai Science and Technology Press, 1983
2: Use smaller motor and control system, Lithium Battery or Gel Battery
3: The speed is not more than 80km / h and the mileage is between 100-200km
6: Some models have EEC certification
7: It has high cost performance