Study On The Precision Characteristics Of Grinding By Extrusion Of Ultrahard Abrasive Grinding Wheel

Grinding has the characteristics of high machining precision,high machining capacity and wide application range.It is generally used for precision machining and difficult machining materials.Among which high grinding temperature restricts the grinding efficiency and causes burns on the grinding surface and residual tensile stress affects the surface strength of the workpiece.In addition,with the development of new materials,the processing of materials is more and more difficult,the existing grinding methods are not suitable.Therefore,higher efficiency,precision and surface quality are important ways to promote the development of grinding.The team developed a new grinding method,super hard abrasive extrusion grinding method.Because of the way squeeze grinding to remove material is squeezed through free grinding grain,free of abrasive and squeezed between the grinding wheel is not solid and even,it has the characteristics of the abrasive cutting speed is low,so is expected to squeeze the effect of grinding process for low speed grinding,which is different from the traditional grinding,good processing surface quality,in addition to squeeze grinding existence of free abrasive to the grinding wheel surface has the effect of repairing refurbished sharp,theory is more suitable for fine-grained super hard abrasive grinding wheel grinding,improve the grinding surface accuracy and performance of the lower surface roughness.The experiment result shows that:1 The precise characteristic mechanism of grinding by extrusion of super hard abrasive wheel.According to the method and mechanism of grinding precision,three kinds of mechanical models of grinding precision were established,which are single free grinding particle extrusion model,multi-free grinding particle extrusion model,free grinding particle flow pressure model and free grinding particle collision model.In this article,the mechanical action between free abrasive and bond and material of grinding wheel is studied.2 The construction of precision extrusion grinding experiment platform.Through the research and test of grinding precision characteristic of super hard abrasive wheel,a grinding precision characteristic test platform is established.The platform is composed of several parts of the portable workpiece clamping device of the force measurement system of the free abrasive fluid circulation system,and the experimental results are measured by the relevant measuring equipment.The platform was composed of several parts of the portable workpiece clamping device of the force measurement system of the free abrasive fluid circulation system,and the experimental results were measured by the relevant measuring equipment.Different grinding experiments can be carried out.Grinding experiments under the conditions of grinding depth and grinding force of free grinding fluid with different grinding wheels.3 Preparation of free grinding suspension for extruding with grinding wheel of super hard abrasive.In this article,the important factors in grinding process and the preparation of free abrasive fluid were studied.In this paper,the method and theory of stable dispersion of micro powder suspension are analyzed,and the optimized preparation process is obtained: the method of combining high speed tangential agitator,ultrasonic oscillator and sodium hexametaphosphate thickening dispersant is used to prepare the stable free abrasive suspension with a certain concentration.4 Experimental study on the precision characteristics of grinding by extrusion of super hard abrasive wheel.1)The analysis of extruding force in the process of extruding shows that the extruding force increases slowly with the increase of concentration and the extruding force is stable under the proper free particle concentration range;When the concentration exceeds a certain degree,it will lead to too many grinding particles,which will make the extrusion force become larger and faster,affecting the stability of the extrusion force.The larger the size of the free grinding particle size relative to the squeeze grinding clearance is,the greater the squeeze grinding pressure will be.When the free grinding particle size is 1/3-1/5of the grinding wheel diameter,the squeeze grinding pressure will remain relatively large and stable;The greater the cutting depth is,the greater the extruding force will be.When the cutting depth is less than the particle size of free abrasive particles,the extruding force will increase slowly due to the online sharpening effect of free abrasive particles;When the cutting depth is larger than the size of free abrasive particles,the online sharpening effect of free abrasive particles reduces the increase of extruding force.Under appropriate conditions,the grain size of the grinding wheel in this experiment can be as low as W3.5.At this time,the grinding force is still stable and good grinding ability is maintained.2)In view of the important factors influencing the experimental study on the precision characteristics of grinding grinding with super-hard abrasive wheel,experiments were carried out on this experimental platform,including free grinding particle density,free grinding particle size,grinding cutting depth and grinding particle size.That's the conclusion.In terms of free abrasive concentration,the surface quality of the workpiece becomes worse with the increase of free abrasive concentration.Therefore,the concentration should be selected between 0.5% and 1% and about 1% when the workpiece surface quality reaches the best.3)The influence of free grinding particle size on precision.When the free grinding particle size is less than the consolidation particle size 1/3 of the extruding grinding wheel,the free grinding particle plays the role of online sharpening and dressing,and the extruding surface quality is better.When the free grinding grain size is greater than 1,the grinding wheel solidifies the grinding grain,and the grinding wheel's working surface is sharpened and dressed unevenly,then the surface quality of the workpiece is poor.4)The influence of the cutting depth in extruding grinding is similar to that in traditional grinding.With the reduction of the cutting depth,the surface quality of the workpiece becomes better and better.In the experiment,the cutting depth of W14 grinding wheel should be less than 5?m.5)Influence of grain size of Grinding wheel on precision of Super hard Abrasive Extruder.The effect of grinding granularity on grinding precision is the most significant.In this paper,different grinding wheels with grinding wheel grain size W14-W3.5 are studied.The experimental results show that the grinding wheel grain size can reach W3.5 and the surface quality of workpiece can reach Ra0.04,reaching the level of precision grinding.