【作者】 许秦；

【导师】 袁巨龙； 文东辉；

【作者基本信息】 浙江工业大学 ， 机械电子工程， 2008， 硕士

【摘要】 硬质材料(如陶瓷、硬质合金等)球体是轴承、圆度仪、陀螺等精密测量仪器中的重要元件,在精密仪器设备中具有十分重要的地位。但是由于传统研磨加工方法的生产工艺受到人为因素的影响,一致性和稳定性较差,加工成本高,难以获得高球度的硬质材料球,使硬质材料球的应用仍受到限制。针对传统研磨方式和一些处于实验室试验阶段的研磨方式的不足,本文提出了一整套高效精密加工技术方案,即固着磨料—双自转研磨方式,全文围绕这种加工方式的基础理论、关键技术和设备研发展开研究,针对硬质材料精密球的成球机理(即切削等概率性和尺寸选择性),从研磨过程中球坯运动状态分析、球坯表面研磨轨迹分布、球形误差修正、陶瓷球材料去除等问题入手,结合固着磨料研磨技术、双自转研磨技术、研磨工艺因素分析等几个方面对硬质材料精密球新型研磨方法进行研究。基础理论方面,分析了球坯的几何运动,观测了研磨过程中球坯运动轨迹,计算、分析双自转研磨方式下运动参数,采用MATLAB对球面研磨轨迹进行仿真。建立研磨过程中单球球形误差修正过程、多球球径一致化过程,对研磨成球过程中成球机理及其影响因素进行了分析。针对硬质材料去除形式的定义和分类,建立了二体和三体磨损模型,从磨损角度阐述了球体研磨过程中的材料去除机理。加工关键技术和产业化设备研制方面,针对硬质材料精密球,提出了一整套新型的高精度球体研磨加工工艺方案,以期初步实现硬质材料球体高效高精度的研磨加工。同时根据提出的新型加工工艺方案,设计了两台产业化设备。目前该设备正在奉化市溪口凯泰精密机械厂抓紧制造中,处于装配、调试阶段。通过在设备样机上的氮化硅球体加工实验结果显示,采用所研制的设备可批量加工出高质量的硬质材料精密球,圆度达到0.05μm,球批直径变动量0.10μm,表面粗糙度Ra 5nm,加工效率比传统的游离磨料研磨加工法效率提高了2倍,初步实现了硬质材料精密球高效、高精度的批量研磨加工。更多还原

【Abstract】 Hardness material (such as silicon nitride ceramics and sintered-carbide ) sphere is considered as one of the most important element for high precision bearing, roundness measuring equipment, top and other high precision machine tool and apparatus because of its desirable properties. They have been successfully used in many fields such as precision machine, aerospace and military instrument, especially in hybrid bearings (ceramic balls and steel races).In this paper, a new type of high efficiency lapping method for high precision hardness material sphere is developed to overcome limitations in traditional lapping process, such as low precision and efficiency, low uniformity and stability of process. Fixed abrasive lapping technology is adopted to lap hardness material sphere in rough-machining stage; Rotated Dual-Plates (RDP) lapping technology is employed to improve hardness material sphere precision and consistency in semi-finishing stage and CMP (Chemical Mechanical Polishing) technology is used to improve high surface quality in finishing stage. The above new style lapping machines have been designed and being manufactured in Ningbo Fenghua Xikou Kaitai Precision Machinery Factory.Lapping trace distribution on ball surface is studied with observing the marked points on the ball surface and 3D simulation of lapping trace. The influence of loading system, lapping parameters and lapping tools on sphere-shaping process is discussed with experiments and theory analysis to study the mechanisms of sphere error correction. The wear mode of hardness material sphere involved in the lapping process is also investigated in this paper. Abrasion tests are performed with different grit size, loads and slurry concentrations on a ball-plate wear test apparatus.In the final part of this paper, silicon nitride ceramics balls are taken as object of a high efficiency lapping experiment .As a result of the experiment, fine sphericity (0.05μm), surface finish (Ra 5nm) and batch diameter variance (0.10μm) are obtained with the total lapping time reduced to about 1/2 of traditional lapping process.更多还原