With the development of control technology, more and more applications are realized by stepping motors for precise control. In economical Cnc Machine tools, stepper motors are often used to drive the actuators to achieve their motion. Rotary EDM is an emerging special processing method developed in China in the past 10 years. It has remarkable processing effects on super-hard conductive materials, especially high-impedance materials such as polycrystalline diamond and cubic boron nitride. In the late 1980s, the Tsinghua University Department of Metal Engineering, which was successfully funded by the National Natural Science Foundation, was the first CNC rotary electric machine tool in China. It has a unique concept and advanced processing technology. It can process planes, outer circles, spiral grooves and various shaped holes. The complex profile of ultra-hard conductive materials such as grooves realizes the processing requirements that can not be completed by traditional machining and ordinary EDM machining, and opens up a new field of electric machining technology. However, the CNC system of the Z80CPU single-board machine used at that time has been difficult to adapt. The practical requirements of the open and integrated CNC system today, therefore, we have improved the microcomputer numerical control system of the machine tool. The three-phase stepping motor is the research object, and the PC is the core of the control system. The interface board is plugged through the ISA bus. The card is driven by the stepping motor drive module, and programmed with the advanced visual language VC++, which realizes the precise automatic control of the stepping motor, and can complete the requirements of the machining system of the various machine tools of the machine tool and its control strategy. Stepper motor control system The machine tool spindle is driven by a DC motor to achieve stepless speed regulation. The key of the control system is to realize precise automatic control of four stepping motors through different combinations of motions. Different control methods can be divided into: the stepping motor moving in a fixed manner is controlled in an open loop manner. The stepping motor required by servo is controlled by closed-loop mode. Each stepping motor can be set into open-loop and closed-loop control modes through hardware and software programs. In open-loop control, the stepping motor starts, stops and force acceleration and deceleration. The control signal sent by the control unit is controlled, and the principle block diagram without the processing state feedback open loop control is as shown. The open-loop control of the stepping motor is controlled in the closed-loop control. The motion state of the worktable and the workpiece driven by the stepping motor is detected by the position feedback system through the gap voltage detection circuit, and is fed back to the core control unit by the core control unit after analog-to-digital conversion. Judging the running state of the workpiece to perform servo control. The control system forms a closed information loop, forming a typical closed-loop control system. The closed-loop control system principle is as shown in the closed-loop control of the stepping motor. The acceleration and deceleration control of the stepping motor is well known. When the starting frequency is too high, the stepping motor will be stuck and cannot be started or lost. If the speed is too high, the motor will overshoot and overshoot when the machine is stopped, so that the stepping motor cannot be accurately controlled. The force deceleration control can solve this problem well. The force acceleration and deceleration control of the stepping motor is gradually increased by the software control torque to reach the required value (due to the program execution moment) Completed to meet the system's response requirements) Deceleration control is also the stepping used by the control system through software In the control system, the stepping motor uses a subdivided driving pulse signal (square wave) with low power, which requires several stages of amplification to achieve the driving requirements. On the other hand, the pulse card provides the pulse to each stepping motor. The ring type distribution circuit distributes the pulses so that the pulse signals are sequentially energized in the phase sequence of the three-phase stepping motor to make the stepping motor operate normally. Analysis of the dynamic characteristics of the stepping motor shows that if the stepping motor works at high speed, then the electrical The influence of the time constant is significantly increased; during the conduction period, the current cannot rise rapidly to the rated value; during the off period, the winding current cannot disappear immediately, and thus the torque generated by the stepping motor is significantly reduced. In addition, the excitation winding will generate a high back electromotive force at the cut-off time. If no measures are taken, the switch may be damaged. Therefore, the stepper motor drive circuit should be: 1. Change the current waveform. The rising edge and the falling edge generate a waveform of a nearly rectangular wave; 2 set a loop for releasing current flow during the off period, reducing the back electromotive force generated at both ends of the winding, and accelerating current decay; in order to improve the resolution and step accuracy of the stepping motor positioning To reduce the overshoot and suppress the oscillation, and meet the above-mentioned driving requirements of the stepper motor. After investigation and research, the company has developed a special control circuit for the full-function stepping motor with subdivision, which is newly developed by Beijing. The rectangular wave power supply is changed to a step wave power supply. At this time, the current in the winding rises to the rated value after several steps, or falls from the rated value to zero in the same way, and the step angle can be reduced without changing the internal parameters of the stepping motor, and the step error Decrease, that is, improve the resolution and step accuracy, and weaken the low-frequency oscillation problem. After the subdivision, the variation of the drive current is greatly reduced, so the excess energy when the rotor reaches the equilibrium position is greatly reduced; on the other hand, the control The frequency of the signal is increased by N times (the number of subdivisions), so it can be kept away from the low-frequency resonance frequency of the rotor. Therefore, the subdivision drive can not only stabilize the stepper motor, but also weaken or even eliminate the oscillation. In addition, because the subdivision increases the number of running shots, it can also obtain a larger working principle of the stepping motor and the specific control scheme. The stepping motor is an actuator that converts the electric pulse signal into angular displacement or linear displacement. Each time it receives an input electric pulse, the rotor rotates a three-phase stepping motor. The rotational speed of the motor is proportionally proportional to the frequency of the frequency. The frequency of the electric pulse is changed accordingly. The speed of the stepper motor. Stop the pulse of the stepper motor and the stepper motor stops. Change the order of energization of each phase of the motor, the steering will change accordingly according to the working principle of the stepper motor, and the above control strategy, we adopt the following specific implementation scheme: the control core adopts the popular open industrial PC, the interface based on ISA bus The board implements the communication link as shown. Bus q pulse card M drive block stepping, machine A / D card gap voltage detection circuit M stepper motor control block diagram stepper motor operation required pulse signal by the timer counter 8253 chip after photoelectric isolation technology processing pulse card designed The program determines the working mode of the 8253 chip square wave generator, and controls the square wave frequency by the preload value of the chip to control the stepping motor speed. The pulse emitted by the 8253 chip is driven by the stepped motor driver with subdivision. The stepping motor driver is a separate module, which can complete the functions of electric pulse ring distribution current subdivision, high anti-interference and fast response, strictly separate the functions of the system machine and the driver, and realize the coordination of the system. action. The forward and reverse of the stepping motor is also realized by the driver setting the high and low level of the I/O card to realize the open loop control system of the stepping motor. The PC and the pulse card and I/O card plugged into the ISA bus, The stepping motor drive module stepping motor and the machine tool table constitute the system to realize the accurate control of the speed and position of the stepping motor and the closed loop control system of the stepping motor for starting and stopping control. On the basis of the open loop control, the gap voltage is passed. After the voltage value detected by the detection circuit is divided, the analog voltage is converted by the analog-to-digital conversion interface board designed by the ADS7808 chip of the new generation A/D device plugged into the ISA bus, and the stepping motor is judged by the program. Operating state, realize servo control. The system consists of a typical closed-loop control system. In each processing mode, each stepping motor is combined with open-loop and closed-loop control to achieve various processing control requirements. ISA bus-based interface board products refurbish second-hand goods market With people's attention to the environment and resources, the remanufacturing problem of old products is getting more and more attention to traditional old products. The “resource recycling†society is analyzed from a technical perspective, and remanufacturing brings “reverse logistics†from consumers to producers. Reverse logistics has different characteristics from traditional logistics, and its research has just started. The corresponding management methods and technologies are still lacking, which limits the development of the remanufacturing industry. Many scholars at home and abroad have done a lot of research on this, such as GeraldoFerrer et al. Modeling and optimizing production planning problems for remanufacturing using the Wagner/Whitin model; MoritzF! Eischmanna et al. have many uncertainties about the remanufacturing inventory. How to manage a basic model remanufacturing definition and related product features Remanufacturing is a process of restoring old products to "new. state in this process, old products Being cleaned, disassembled and inspected, parts with re-use value are reprocessed, and then inventoried to reassemble the remanufactured parts of the inventory (or add appropriate new parts) into "new" products, making them Products with the same performance and longevity that can be remanufactured generally have the following characteristics: 1) durable products; 2) some functions are damaged; 3) standard parts, each part can be replaced; 4) residual value High, and the cost of remanufacturing is lower than the residual value; 5) the technical indicators of the product are stable; 6) the customer agrees and can accept the remanufactured product. Currently remanufactured products include electronic equipment, automobiles, engine copiers, printers, and the like. The input and output control system consisting of a refurbished pulse card, an I/O card, an A/D card, and a dedicated drive module for the stepping motor is used to control the direction and speed of the stepping motor to drive the workbench. According to the expected target motion, the subdivision drive circuit improves the resolution and step accuracy of the system, and makes the stepper motor run smoothly, weakens or even eliminates vibration, and improves the organic combination of the starting torque open loop and the closed loop control system to realize the machine tool. Various processing movements have been experimentally verified that the system is simple in control, reliable in operation, and has good versatility. (Finish)
Jiantong Hardware is also focused on manufacturing various sheet metal enclosures. Material scope include copper, Iron, Aluminum, Stainless steel and Spring steel with various of function and thickness. Surface treatment we are capable to process contains electro plating, powder coating ,painting,electrophoresis, sand spraying, brushing, anodizing, polishing, passivation, silk screen, laser cutting....etc. Final products are electrical metal steel cabinet, metal case, electric enclosure, Junction box, storage box, switch box, sheet metal housing, metal case.
In order to fully meet internal market and customers requirements,we control quality from source beginning,like product design, technical support, supplier election, etc. All materials are of RoHS & Reach compliant. Meanwhile, we brought in advanced testing equipment such as 2D tester, projector, Salty Spray Tester, coating thickness tester, sclerometer and so on, which can enhance testing and quality controlling ability in further.
Sheet Metal Enclosure,Metal Enclosure,Stainless Steel Enclosure,Metal Enclosure Box Nanpi Jian Tong Hardware Manufacturing Co., Ltd. , https://www.sheetmetals.nl
