| High-frequency induction brazing technology is widely used in mass production of PCD tools with the advantages of short heating time,low equipment cost,easy operation,and no pollution.However,there is always a thermal damage layer on the rake face of PCD tools made with this technology,which causes the flatness of the rake face of PCD tools after welding to be reduced,and the original mirror surface to be damaged.It is easy to make the tool stick to the workpiece base material when cutting highly plastic metals such as titanium,which affects the machining quality and performance of tools.For this reason,the finishing process of removing the thermal damage layer of rake face of PCD tools after welding has become an urgent problem to be solved.In order to meet the requirements of flexibility and precision of the processing method for the mirror finishing of the rake surface of PCD tools after welding,the cloth wheel polishing method is adopted to remove the thermal damage layer of PCD tools.We make a deep and systematic study on the polishing technology and theory of this method.Firstly,the influence of rotation speed and compression of cloth wheel on the polishing force was studied during the process of removing heat-damaged layer on the rake face of PCD tools by cloth wheel polishing through a single factor test.When the compression is within a reasonable range and the rotation speed is constant,the polishing force increases with the increase of compression amount.When the compression amount is constant,the polishing force increases with the increase of rotation speed.However,when the amount of compression is too small or large,the polishing force becomes unstable due to the influence of the cylinder roundness error.Then based on the single-factor test data,a two-factor four-horizontal orthogonal test table is obtained under the steady state of polishing force.The degree of influence of compression amount and rotation speed of the cloth wheel on the polishing force is analyzed,and a polishing force prediction model is established.Then,three-factor four-level orthogonal experiment is conducted to study the influence of technical parameters on roughness change value ?Ra of PCD tools during the cloth-wheel polishing process which removes thermal damage layer of PCD tools.Roughness change value ?Ra increases first and then decreases with the increase of rotation speed,increases first and then decreases and increases again as compression amount increases,increases first and then decreases with the increase of polishing time.Following above job,the influence degree of cloth-wheel speed,compression amount and polishing time on the change value ofthe roughness is analyzed,and a ternary-quadratic prediction model of roughness change value is established.Finally,a test of PCD tools cutting titanium alloy was designed to investigate the variation of the rake face adhesion area of PCD tools and workpiece surface roughness with change of rotation speed,compression amount,and polishing time.The relationship between the adhesion area S and the surface roughness of the workpiece and ?Ra is also discussed.Adhesion area decreases first and then increases as the rotation speed increases,decreases first and then increases and decreases again as the compression amount increases,decreases first and then increases as the polishing time increases.The effect of polishing parameters on the roughness change value and adhesion area is basically consistent,and there is a good correlation between them.The surface roughness of the workpiece increases first and then decreases and increases again as the speed increases,decreases first and then increases and decreases again as the amount of compression increases,increases first and then decreases as the polishing time increases.There are many external factors that affect the surface roughness of the workpiece,so there is no obvious correlation between the surface roughness of the workpiece and the adhesion area. |
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