Study On Ultrasonic Assisted ESD Deposition Automatic Control System And Process

Traditional ESD equipment have the phenomena of"anode adhesion"and arc pulling during the deposition process,and the deposition equipment is mostly manually operated.Human factors have a large influence on the quality of the deposition layer,hand-held deposition guns are not suitable for large areas of deposition work and inefficient work,affecting the quality of the deposition layer.Ultrasonic processing is used in combination with ESD deposition technology by adding ultrasonic vibrations to the tool electrode on the basis of ESD to enhance the processing conditions in ultrasonic vibrations assisted ESD process.Using WC-10Co metallic hard alloy rods as electrode,WC-based alloy coatings were prepared on S136 die steel surface by using the electro-spark deposition automatic deposition platform to deposit.The effects of current,voltage,pulse frequency and ultrasonic vibration frequency deposition process parameters on deposition layer thickness.The surface roughness and deposition layer defects were investigated.And the process parameters of ultrasonic compound ESD automatic deposition were optimized by orthogonal experimental design.Analysis of the morphology,surface roughness,elemental distribution,microhardness and frictional wear properties of the deposited layers at the optimum deposition process parameters.(1)In this paper,a rotary ultrasonic compound ESD deposition gun was designed,The ultrasonic working system is consisted of ultrasonic transducer,sandwich type piezoelectric ceramic,half wavelength composite variable amplitude rod and fixture.The rotating spindle is consisted of a speed-controlled DC motor with a collector ring.The rotating spindle speed is continuously adjustable from 100-200 r/min.A set of ESD automatic control system is designed based on Labview as a development platform,and the hardware of the system is mainly composed of an Arduino control card and a stepper motor.The system has the functions of motion control,motion feedback,data collection,deposition track setting,display and the like,therefore the automatic control over an ESD process is realized.(2)The current and voltage of the deposition processing have high effects on the thickness,roughness and flow of deposition coatings.The higher the current and voltage,the thicker the deposition layer,the greater the surface roughness of the deposition layer and the more defects in the deposition layer.Increased deposition pulse frequency,increased deposition layer thickness and smoother deposition layer surface.The mechanical force generated by the ultrasonic vibrations makes good contact between the poles.As the frequency of ultrasonic mechanical vibration increases,the surface roughness of the deposited layer decreases and defects are reduced.Through orthogonal design experiments and optimization experiments,the best process for deposition WC-10Co alloy was selected:the current of 7.5A,the frequency of 2000Hz,the ultrasonic vibration frequency of 20000Hz,the deposition gun angle of 60°,the spindle speed of 200r/min and the deposition time of 5minutes.(3)Under the best process parameters,the WC-10Co deposition layer is prepared by automatic and manual methods.The surface of the deposition layer prepared by the automatic deposition platform is dense,smooth and has few defects.The surface roughness of the automatic deposition is 3.2.The surface roughness of manual deposition is 3.9;the average microhardness of the automatic deposition layer is1360HV0.2,the average microhardness of the manual deposition layer is 1100HV0.2,and the average microhardness of the S136 mold steel substrate is 185HV0.2;the deposition layer is prepared automatically The amount of wear is about 1/5 of the manual deposition layer and 1/9 of the S136 mold steel;the surface of the prepared deposition layer forms a good metallurgical bond.The deposition coating is mainly consists of amorphous,such as Fe₆W₆C,Fe₃C and Cr₂₃C₆phases.