【作者】 范前峰；

【导师】 傅惠南；

【作者基本信息】 广东工业大学 ， 机械制造及其化， 2012， 硕士

【摘要】 金刚石具有突出的物理、化学、机械性能,在先进的科技和工程技术领域中得到了广泛的应用,特别在超精密加工的领域中,通常被用作超精密切削刀具材料。随着科技和应用的发展,对金刚石的表面质量提出了更严格的要求。但金刚石具有的高硬度、易脆、耐磨等特异性能,同时获得高精度及粗糙度值低的金刚石表面极其困难。所以进行金刚石的精密研磨加工技术研究,具有很好的应用前景和实用价值。在弹性浮动研磨加工过程中,加工条件、设备和相应的控制系统是影响金刚石研磨精度和效率的重要因素,其中改进研磨设备控制系统,提高研磨装置运行的精度和平稳性成为能否加工出高精度金刚石表面的关键问题。本文首先讨论和分析影响研磨装置运行精度和平稳性的主要因素,在此基础上提出基于精密流体动力轴承、采用无位置传感器无刷直流电机技术设计高速运转平稳的小型精密主轴系统；进给系统采用精密的伺服电机进给平台进行径向进给。从金刚石研磨原理出发,探讨了金刚石表面出现解理、划痕等加工缺陷的产生原因是：金刚石表面在研磨加工过程中受到了不断变化的冲击。从弹性浮动研磨后的金刚石表面可以看出,不断变化的冲击主要来白研磨盘的端跳和弹性梁的振动。研磨过程中不同径向位置研磨盘的端跳会使得金刚石表面和研磨盘之间发生变化的撞击,而无法达到所需的加工精度和表面质量[1]。为了抑制在径向进给过程中端跳造成振动和冲击对金刚石研磨表面质量的影响,本文采用在径向进给过程中实时调整进给速度的策略,对工件表而的冲击进行控制。本文提出通过调节径向进给速度来控制端跳造成的冲击。然后,结合弹性浮动研磨的特点分析比较了常用控制方法的优缺点,选取了合适的控制方法及制定了分阶段调速进给的冲击控制策略,同时设计了冲击控制系统的总方案。在此基础上,根据控制系统的性能要求对系统的各个部分进行分析、设计及选型,按照控制系统构成原理对其进行数学建模,求出了控制系统的开环传递函数,并使用之前选取的控制方法设计出冲击控制器与系统的开环传递函数一起进行了全闭环仿真实验。最后,使用LabVIEW软件开发环境编写出了控制系统,构建控制策略验证系统,对所设计的控制策略及控制系统进行了验证。更多还原

【Abstract】 Diamond has some excellent performance in physics、chemistry mechanism. Diamond has been playing an important role in technology and industry. Especially, in the field of ultra-precision machining, diamond is considered the best ideal of ultra-precision cutting tool materials. with the technology and application development, People on the diamond surface made more stringent requirements. As the rigid material properties of diamond, Generally, Obtain a shape of the required accuracy and surface roughness of the difficulties of low diamond, Thereby, the precision diamond lapping technology, Have a good prospect and practical value.In processing of diamond lapping, there arc some factors which influence diamond lapping, like process condition, equipment and corresponding control system. But most important and base problem is improving lapped equipment control system, so how to improve move’s precision and stabilization of lapped machine is the key problem. This paper first discusses and analyzes the main factors of influence grinding device running accuracy and stability. The minitype and precise spindle system has been designed and done. It adopts fluid dynamic bearings technology and sensorless BLDC motor techcnology so that spindle system can rotates stably and precisely. Feeding system adopts the precision of servo motors into platform to radial feeding.We started from the diamond grinding mechanism to explore the nature of the reasons for the phenomenon of emergence of cleavage and micropore on the diamond surface:the phenomenon of cleavage and the micropore is due to the instable impact during the diamond lapping. We can see, from the diamond surface after elastic float lapping, that the variational impact is mainly produced by the end beating of grinding disc and the vibration of elastic beam. These interferes both vibration and impact different radial positions will make relative motion between the lapped diamond tools and grinding disc so that diamond tools cannot achieve the required processing precision and surface quality1". In order to restrain the vibration and impact caused for end jump to the diamond grinding surface quality in radial feeding process, this paper take use of the strategy by the adjustment of speed in the radial feeding process timely to control the impact on the surface of diamond.This paper proposes an idea of controlling radial feeding speed to regulate the impact from the end jump. With the characteristic of elastic floating grinding, pros and cons of commonly-used methods are analyzed and compared. After that it selects out the appropriate methods and works out the grinding control strategy offers in phases, meanwhile the overall program of grinding control system has been designed. On the basis of those, with the function desire of the control system, analyze, design and choose models of every part of the system. A close-loop simulation was made by putting the open-loop transfer function and the controller together. At last, the software of the control system has been programmed in LabVIEW environment, and impact control method verifying system is used to inspect the practicability of the system.更多还原