Precision Grinding Process Of YB-70and Grinding Wheel Wear

Machine tools are more precise to satisfy greater demands on surface quality and precision of the rolled products. The work roll and backup roll, as the key components of the mill, have to be accuracy and high quality. For example, some large-scale and heavyburden backup roll made by new material, and2500mm in diameter,200t weight, requires Ra0.1-0.2μm in surface roughness, the accuracy IT4-IT5. Precision grinding experiments on YB-70steel workpiece were done, and analysed surface roughness of the YB-70steel after precision grinding, the influence of grinding parameters, the regular pattern of wheel wear. Details as follow:(1) Analysed the factors of precision grinding quality and accuracy of YB-70steel based on orthogonal experiments on precision grinder using silicon carbide grinding wheel. The influence of abrasive grain size, wheel speed, cutting depth, workpiece length feed and infeed speed were obtained based on variance analysis on test results.(2) Optimized precision grinding process parameters aimd for highest grinding efficiency, including certain contrains:the grinding quality requirements, the grinding force, conditions to prevent burns and the performance of precision grinder. The optimization model was solved using particle swarm algorithm. Surface roughness and machining accuracy is satisfied by the grinding parameters gained, verifying the validity of the model.(3) Analysed the formation of precision grinding surface, established a prediction model, based on BP neural network optimized by genetic algorithm, to predict the precision grinding roughness values of the YB-70steel. The comparison of simulation and actual measurement results shows that the average relative prediction error is approximately8.14%. And be able to find the combination of grinding parameters where the roughness is minimum.(4) Because a long time is needed, bulk material is removed, the wheel wear is serious when precision grinding backup roll. Wheel wear mechanism and influencing factors were analyzed. The wheel wear law and changes of surface quality were examined based on grinding wheel wear test. The results show that, the selected grinding wheel is well self-sharpening during the test, and the surface roughness does not exceed the bounds.