In order to study the effect of rotating electrode contact force on discharge parameters and material transfer in electric-spark deposition (ESD), the automatic ESD experiments under different contact forces were carried out. The number of various discharge waveforms, discharge parameters such as average voltage and current of discharge pulses, transfer efficiency and deposition efficiency of ESD, surface morphology and cross-section morphology and surface roughness of the deposition layer under different contact forces were analyzed. The results show that the change of contact force affects the number and proportion of various discharge types during the automatic ESD process with rotating electrode. With the increase of contact force, the proportion of contact discharge decreases gradually while the proportion of short-circuit discharge increases gradually, and the average voltage and average power of discharge pulse decrease gradually while the average current increases gradually. The contact force has a great effect on the transfer efficiency and deposition efficiency of ESD, but has little influence on surface roughness. When the contact force is 1 − 2 N, the proportion of contact discharge, transfer efficiency and deposition efficiency are higher in the automatic deposition process. The amount of material transfer caused by contact discharge is significantly higher than that caused by short-circuit discharge during the automatic ESD process with rotating electrode.
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