Research On The Key Technologies For The Development Of High Speed Precision Horizontal Machining Center

NC technology is one key technology in modern manufacturing industry. Flexible manufacturing system composed of NC machines is the basic equipment to update traditional mechanical industry and built up digital enterprises. Its development and application represent, to a certain degree, the country's manufacturing level and competitive edge. Therefore, it catches close attentions from the manufacturing industry all along. As a important NC machine, high speed precision horizontal machining center is the key equipment urgently needed for our country's automobile, aircraft and precision mould manufacturing industries. However, at present, there is a biggish disparity in design technology, manufacturing technology and machine performance between domestic HMC and oversea HMC. The disparity becomes more apparent in basic theory and key technology research and study.Supported by the National Key & New Product Developing Program and with reference to Ningjiang Group's own developing strategy and marketing experience, The article gives a detailed theoretic analysis and application research for Ningjiang Group's independently developed High Speed Precision Horizontal Machining Center-THM6363 and bring forward the general proposal, structure design, performance analysis, manufacturing process and accuracy checking methods. The developing pattern, concerned theory and some key technology for NC High Speed Precision Horizontal Machining Center is discussed in the article as well. Main achievements and features in the paper are as follows:(1) Through analysis and comparison between oversea and domestic high speed machining center, the article indicates that the High Speed Precision Horizontal Machining Center-THM6363 is designed for small and medium size precision components used in aircraft, military and mould manufacturing industries. It introduces the design requirements and key technologies for High Speed Precision Horizontal Machining Center and lay out a plan to develop high speed, high efficiency, high precision and high reliability machining center with special characteristic of Ning-Jiang brand.(2) Based on the analysis on structure and general layout for domestic and oversea horizontal machining center, the article brings forward a general proposal to develop a High Speed Precision Horizontal Machining Center for small and medium size precision parts. By reference to the theory of "uniform integrated displacement and rigidity ", the worktable is designed to feed in axial direction together with the workpiece. This structure ensures uniform integrated displacement and rigidity and guarantees stable working accuracy.(3) The article gives a detailed study for the structure of spindle system, drive system and rotary worktable of THM6363 High Speed Precision Horizontal Machining Center. It lays out the design method for spindle structure, designs the drive system which is integrated by high speed ball screw and linear guideway, introduces the calculation rules for load inertia and torque of inertia motor, sets up the analysis and calculation principle for transmission torque of worm pair on rotary worktable and intensity of fastening screw on hydraulic cylinder.(4) FEA analysis and optimum design is applied for the column and machine body of THM6363 high speed precision HMC by CAD/CAA technology. FEA Modeling is set up and modal analysis is carried through. Natural frequency and the concerned vibration mode is introduced for the former 5 stages and the resonance zone of the machine is confirmed. Some optimum design for the column is tried as well. Base on above research, we tested the machine performance, verified the conclusion of finite element dynamic analysis and provided some theoretic basis for machine structure optimization.(5) The article provides a detailed study to the manufacturing technology concerned with High Speed Precision HMC and analyzes the machining process for spindle, scraping process for guideway, assembly process for rotary worktable and pre-tighten stress for ballscrew. And finally put forward the process flow and manufacturing method which match the company's actual requirement.(6) Accurate position control is the key factor for precision NC machine. Therefore, the article analyzes the factor which influence perpendicularity and positioning accuracy for each axis and bring forward the technology for perpendicularity measurement and adjustment. Full-closed-loop encoder and ball bar instrument is introduced respectively for positioning accuracy and roundness checking. Above application plays a significant role to ensure the assembly quality, the machining quality and the accuracy of the machine.(7) High speed cutting tool, high speed cutting process, interface for cutter and machine were analyzed and discussed. A method is introduced to select suitable working process and cutting parameter for high speed cutter used on HMC. The new technology of low-temperature-cool-air cutting is applied for the HMC to ensure minimum cutter wear at high speed condition.(8) Base on above achievements, an integration technology for high speed precision HMC developing was formed. We successfully developed our THM6363 HMC and put it into mass production. Our research on high speed precision HMC bring us favorable social and economic benefits (The research is supported by the National Key & New Product Developing Program and the machine is awarded provincially as excellent new product).