Research On Combined Milling Tool And Cutting Performance In Threaded Hole Machining Of 15-5PH High Strength Steel

High-strength steel materials have high hardness,high wear resistance,high toughness and other properties,and are widely used in automotive,aviation,mechanical equipment and other fields.High-strength steel is a difficult-to-machine material.If the threaded hole is processed by traditional techniques(drilling-reaming(boring)-tapping),it will cause serious tool wear,poor processing quality,and low processing efficiency.Therefore,this thesis proposes the compound processing technology of milling instead of drilling and milling instead of tapping.At the same time,designing combined milling tools and optimizing angle parameters and thread profile to achieve high-precision and high-efficiency machining has important guiding value for engineering applications.This thesis takes combined milling tools for processing threaded holes of 15-5PH high-strength steel as the research object,uses geometry and envelope surface theory to analyze the tool structure,uses UG,VERICUT,MATALAB,AdvantEdge and other tools to analyze the threaded hole processing process,and uses multi-axis CNC machine tools,automatic image measuring platforms,three-way dynamometers and other equipment to conduct research on the cutting process.The influence of tool angle parameters,profile parameters,and cutting parameters on the processing of threaded holes in high-strength steel is explored,in order to improve the combined milling tool performance of threaded holes in high-strength steel.The specific research content is as follows:1)The process of spiral milling and thread milling is described,and the cutting part of the two processes is determined.The basic principles,machining steps and cutting parameters of the compound machining process are introduced.Based on the structure of the end mill,a combined milling tool for threaded holes was preliminarily designed.2)Parameter optimization and verification of combined milling tools for 15-5PH(H1150)high-strength steel threaded hole.The cutting process of the two parts of the cutting edge of the combined milling tool is analogous,and the single factor experiment method is used to simulate the turning and milling process of 15-5PH(H1150)high-strength steel using AdvantEdge software.The law of the influence of tool parameters on the maximum cutting force and the maximum temperature of the tool surface,and a better parameter range is obtained.Then,the orthogonal experiment method is used to explore the influence of combined milling tool parameters on the maximum cutting force and the maximum temperature of the tool surface.The effectiveness and reliability of the optimized scheme is proved through the processing experiment of threaded holes.3)Thread machining error analysis,optimization and verification.The machining error of the combined milling tool is visualized through the VERICUT cutting simulation software.The contour of the combined milling tool and the standard triangle thread profile are defined,and the trajectory equation of the combined milling tool center is established.Combining the tool contour and the tool center equation,the combined milling tool envelope surface equation and the threaded hole error calculation model are established.For threaded holes with diameters of 12 mm,14mm,and 16 mm,a comprehensive optimization plan is established by adjusting the feature points of the tool,and the optimized combined milling tool thread profile feature points are obtained.Finally,the automatic image measuring instrument is used to compare the thread machining errors before and after optimization to verify the accuracy of the error calculation model and the reliability of the optimization scheme.4)Research on cutting force of 15-5PH(H1150)high-strength steel threaded hole compound machining.A full-factor experiment program is designed,and the influence of process parameters on cutting force is explored.For the three diameters of 12 mm,14mm and16 mm,better process parameters are obtained,and based on experimental data and related modeling theories,a multiple regression cutting force model for compound machining of15-5PH(H1150)high-strength steel threaded holes is constructed.