单线往复式金刚石线切割张力的建模与控制

发布时间：2018-09-17 12:17

【摘要】：SiC单晶凭借优良的特性成为了第三代半导体的核心材料,但是SiC材料高硬度、高耐磨的机械特性和稳定的化学特性使加工成为了难点。在将SiC碇加工成晶片的过程中,切割工艺占有重要的地位,切割质量对后续加工工艺影响甚大。实验显示,在固结金刚石线锯切割SiC单晶片的过程中,线锯的振动对切割质量有着显著的影响,而线锯张力是影响线锯振动的重要因素,对线锯张力的控制能够有效地减小线锯的振动,从而提高切割晶片的表面质量。本文基于单线往复式金刚石线切割走丝系统的动力学特性,构建了走丝系统张力的数学模型,研究了走丝速度、导轮摩擦系数、导轮转动惯量等参数对走丝系统线锯张力的影响规律,其中:走丝速度与张力变化量成线性关系,线锯的张力随着走丝速度的增大而增大;导轮的摩擦系数与导轮的转动惯量主要影响的是走丝系统启动、换向和制动过程中张力变化量的波动特性,前者越大,后者波动越大。设计了一种基于压力传感器与丝杠传动的线锯张力控制器。完成了控制器机械结构的设计、主要零部件的选型以及控制器硬件系统的设计。基于TMS320F28335型DSP芯片实现了线锯张力的实时采集、电机转速控制以及控制器与上位机的通讯等功能。使用LabVIEW图形化编程软件开发了张力控制器的人机交互界面,实现了张力控制器控制参数的设置、张力的实时显示以及记录等功能;提出了一种用于走丝系统张力控制的模糊-PID控制器,与传统PID控制器相比,模糊-PID控制器能够在不同走丝速度时对线锯张力进行更有效地控制。完成了张力控制器的软硬件调试与实验,验证了线锯张力控制器的有效性。实验结果显示,换向时线锯张力在开环控制中会急剧的增大或者减小,并且线锯的张力变化量具有分段性。本文设计的张力控制器在走丝速度为8.52m/s～15.55m/s时可有效抑制换向张力的突变,使得线锯张力变化量的范围从开环时的3.6N到闭环时的0.4N。
[Abstract]:SiC single crystals have become the core materials of the third generation semiconductors by virtue of their excellent properties, but the high hardness, high wear resistance and stable chemical properties of SiC materials make it difficult to process. In the process of SiC Anchorage processing, cutting technology plays an important role, and the cutting quality has a great influence on the subsequent processing process. The experiment shows that the vibration of the wire saw has a significant effect on the cutting quality during the process of cutting the SiC single crystal slice with the consolidation diamond wire saw, and the tension of the wire saw is an important factor affecting the vibration of the wire saw. The control of the wire saw tension can effectively reduce the vibration of the wire saw and improve the surface quality of the cutting wafer. In this paper, based on the dynamic characteristics of single wire reciprocating diamond wire cutting system, a mathematical model of wire walking system tension is constructed, and the speed of wire walking and the friction coefficient of guide wheel are studied. The influence of the parameters such as the moment of inertia of the guide wheel on the tension of wire saws is discussed. Among them, the wire speed is linearly related to the variation of wire tension, and the tension of wire saws increases with the increase of wire speed. The friction coefficient of the guide wheel and the moment of inertia of the guide wheel mainly affect the fluctuation characteristics of the tension variation in the starting, reversing and braking process of the running wire system. The greater the former is, the greater the fluctuation of the latter is. A wire saw tension controller based on pressure sensor and screw drive is designed. The design of mechanical structure of controller, the selection of main parts and the design of controller hardware system are completed. Based on TMS320F28335 DSP chip, the functions of real time acquisition of wire saw tension, motor speed control and communication between controller and upper computer are realized. The man-machine interactive interface of tension controller is developed by using LabVIEW graphical programming software. The functions of setting control parameters of tension controller, displaying and recording tension in real time are realized. This paper presents a fuzzy pid controller for tension control of wire walking system. Compared with the traditional PID controller, the fuzzy pid controller can effectively control the tension of wire saws at different wire speeds. The software and hardware debugging and experiment of the tension controller are completed, and the validity of the wire saw tension controller is verified. The experimental results show that the tension of the wire saw increases or decreases sharply in the open-loop control and the tension variation of the wire saw is piecewise. The tension controller designed in this paper can effectively restrain the abrupt change of commutative tension when the wire speed is 8.52m/s~15.55m/s. The range of tension variation of wire saw is from 3.6 N in open loop to 0.4 N in closed loop.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ163.4

【参考文献】