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Investigation on Machined Surface Quality in High-Speed Ball-end Milling of Mold Steel

Author: LiYueEn
Tutor: ZhaoJun
School: Shandong University
Course: Mechanical Manufacturing and Automation
Keywords: High Speed ??Ball Milling Surface quality Pose tool Residual stress
CLC: TG54
Type: PhD thesis
Year: 2011
Downloads: 296
Quote: 1
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Abstract

High-speed ball milling technology is widely used in the field of mold cavity, the mold surface quality related to product processing quality and life of the mold. High-speed ball milling the surface of the formation mechanism of the essence summarized as: milling generate periodic nonuniform stress field and temperature field coupling effect on the surface of elastic-plastic material, the material surface elastic recovery and plastic deformation, thus affecting the geometric accuracy and surface metamorphic layer process of physical and mechanical properties. Cutting parameters and tool position and orientation, and other processing parameters through the combined effect of high-speed ball milling machining surface residual stress, roughness and work hardening. This paper studies the integrated use of surface quality analysis, simulation and experimental methods, the surface quality forecasting, optimization and control with new ideas and new methods, and so developed a new algorithm to adapt to the surface quality of projected demand. In this paper, metal cutting theory, for ball milling characteristics, application of differential geometry theory, the S-shaped cutter blade cutting edge line equation by cutting force infinitesimal ball milling cutting force model for simulation, analysis of its milling force variation; combined ball milling cutter posture and trajectory characteristics, experimental studies of the ball head milling cutting forces and tool position and orientation, spindle speed and other processing parameters of relations and further reveals the ball milling parameters on cutting force The impact mechanism and laws. Based on high-speed ball milling characteristics studied ball milling periodically varying thermal loads and mechanical loads on the machined surface stress field and temperature field are analyzed machined surface morphology of the formation mechanism of the machining deteriorated layer formation law, and further reveals the ball speed milling cutter mechanism formed on the surface. The use of non-destructive testing methods surface residual stress, high-speed ball milling on the surface after the measurement of residual stress, surface residual stress was found in the presence of tool path direction stress \H13 tool steel, high-speed machining conditions rake angle and side angle between the surface residual stress prediction model; through the side slip angle single factor experiment is given based on knife - Gongli simplified model to calculate the finishing conditions residual stresses generated extreme sideslip angle and anteversion combined results; studied under multi-axis CNC machining cutting parameters and residual stress between the mechanism of action, reveals the tool position and orientation and the relationship between the surface residual stress is established surface residual stress and tool anteversion polynomial fitting formulas analyzed anteversion affect the residual stress of the law. From the experimental point of processing parameters on the comprehensive study of the high-speed ball milling surface quality. Through single factor experiment and multi-factor experiments, revealing the cutting parameters on the surface quality of the law, gives a multi-parameter for the quality of the machined surface saliency sequence analysis of various factors on the quality of the machined surface impact mechanism. In the experimental study and the cutting parameters on the surface quality of mechanism, based on the establishment of a radial width of cut, axial depth of cut, feed per tooth and anteversion angle on the side between the various surface quality parameters Multiple linear regression models; combining artificial neural network research, comparison and analysis of the BP neural network, multiple linear regression model was applied to predict the surface quality of the advantages and disadvantages, with \MLBP and BP neural network prediction model. With this model, predicted by interpolation of data preprocessing, without reducing the accuracy of predictive models based on the prediction model improves the generalization ability and robustness. Based on ball speed milling cutter formation mechanism of surface quality and surface quality prediction method, the preparation of a set of secondary development of surface quality prediction programs, and procedures of the software.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metal cutting and machine tools > Milling and milling machine
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