| As a new type of grinding tool,CVD diamond grinding wheel has the advantages of no binder,high particle density and good wear resistance.However,due to the narrow chip space on the surface of the grinding wheel,it is easy to cause clogging of the grinding wheel during grinding,and laser structured methods are often used to increase the chip space on the surface of the grinding wheel.The thermal effect of laser processing will cause some of the removed material to recast around the processing area after solidification or sublimation,forming a recast layer that is difficult to remove at a later stage,making the edges of the processed microstructure irregular and blocking subsequent lasers Pulses reduce the efficiency and accuracy of laser processing.In order to solve the above problems,this topic studies the water film assisted pulse laser processing technology of CVD diamond coating.Use a spray to form a fast-flowing ultra-thin water film on the laser-processed surface.Using the erosion and cooling of the water film and the micro-impact formed by the laser and the water film removes the recast particles to obtain a structure without recast layer and complete structure on the CVD diamond grinding wheel.This article has conducted the following aspects of research.First,the fluid simulation of the water film formed by the spray hitting the wall was carried out,and the influence of the distribution characteristics,feature size and spray parameter changes of the water film was obtained.By analyzing the characteristics of the water film,The area suitable for water film assisted laser processing was found.,and then built an experimental platform of water film assisted laser processing.The difference between water film assisted laser processing and other forms of water assisted laser processing is compared from the perspective of ablation morphology,surface composition and theoretical analysis.It is found that water-film-assisted laser processing can effectively remove the recast layer generated by laser processing while ensuring processing accuracy and continuity.Secondly,the research on water film assisted laser processing technology was carried out,and orthogonal experiments were carried out on the six influencing factors involved in the processing,and significant factors affecting the characteristics of water film assisted laser ablation were obtained,and then a single factor experiment was conducted on each factor,The rules of the influence of different factors on the characteristics of water film assisted laser ablation are obtained;and the groove width of the single-scan processing of the built system is in the range of 20-40 ?m and the depth is in the range of 30-300 ?m.At the same time,based on the theory of laser ablation threshold and the effect of water film on the laser processing process,a water film assisted laser ablation model was established,and the established ablation model has good consistency with the experimental results.Finally,the three-dimensional morphology modeling of the surface of the structured CVD diamond grinding wheel was carried out to obtain the number of effective abrasive particles and the distribution of the feature size.The width,structure rate and angle of the microstructure were studied to effectively grind the grinding wheel surface.The influence rules of parameters such as the number of grains,the width of the abrasive blade and the interval of abrasive grains.Then,square structure ablation was carried out,and the water film assisted laser ablation model was revised and improved.Based on the surface morphology model of the grinding wheel and the water film assisted laser ablation model,the microstructure of the surface of the grinding wheel to be processed was selected to determine the required process parameters,and the water film assisted pulse laser processing technology was successfully used to obtain a non-recast layer Structured CVD diamond wheel with complete structure. |
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