| Micro-hole group is a relatively common structure,microporous materials are processed because of the high rigidity and heat dissipation.Therefore,micro-hole structures with a large number of complex positional relationships are designed and widely used in aerospace and automotive parts.At present,EDM is one of the main ways to process micro-holes.Summing up the previous research experience,we can see that in the EDM process of micro-holes,the flow of the cutting fluid between the electrode and the workpiece is not smooth due to the small hole diameter,which often leads to difficult discharge of chips,heat dissipation difficulties,easily deformed hole diameter,and bad discharge environment.Incomplete discharge often causes excessive electrode loss,poor workpiece processing accuracy,and low power utilization.In addition,micro-hole processing is usually deeper in the aperture and more in number.Therefore,micro-holes have become one of the key research subjects for fine structure processing.This paper has developed a set of multi-micro hole EDM vibration compound processing equipment.Different from the traditional EDM machine,the device has multi-electrode synchronous rotation,independent discharge of each electrode,and the vibration device promotes chip removal.By analyzing the processing efficiency of the electrode vibration and rotation in theory,the overall structure of the device was designed,and the structural characteristics,installation methods,relative motions,and functions of each component were discussed.According to the principles from bottom to top,complexity to simplicity,through ANSYS-aided design and theoretical analysis,based on the principles of lightweight structure and non-interference in assembly,the upper and lower discs,vibration shaft,vibration motor support plates and spring support plate were determined.The dimensions of the board were checked to ensure that the part size meets the processing requirements.The reliability of the device was analyzed,including structural analysis of interference fit,fatigue life,electrode eccentricity,and performance of the feed mechanism.The dynamics analysis was performed under the maximum excitation force of the electrode.The curve of speed and displacement over time validates the rationality of micro-vibration of the electrode.Based on the structural design,the supporting control program was developed.The output pulse of the STM32 was used to control the speed of the rotary motor and the vibration motor.The drive was used to control the rotation angle of the stepping motor and then the differential feed of the slide table was controlled;the USMART was used.Realize the start,stop and real-time speed regulation of the motor through the serial port.The device was subjected to structural installation and debugging,circuit debugging,program debugging and joint debugging.After the debugging was correct,experiment was designed to verified the electrode vibration and rotation to enhance the processing efficiency;finally,four factors and three levels of orthogonal experiment and response surface experiment was designed based on the control pulse duty cycle of the rotary motor and vibration motor,processing voltage,material thickness,in order to obtain the time required for processing galvanized stainless steel under the conditions of different control pulse duty ratio,voltage,and thickness,which were calculated by Design Expert software.Multivariate regression analysis and correlation analysis was established to search for ideal process parameters and verify the practicality of the device. |
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