【作者】 郑毅；

【导师】 徐国成；

【作者基本信息】 吉林大学 ， 材料加工工程， 2004， 硕士

【摘要】 由于激光具有方向性好、高能量和单色性好等一系列优点，自问世以来，就受到高度重视，应用范围越来越广，特别是在加工领域，随着激光加工市场不断扩大，激光加工在整个加工业的比重已占相当大的比重。在此环境下研究设稳定性好，可靠性高，智能化水平高的激光加工系统，对于激光加工技术的应用与推广将很有意义。由于激光微加工对精度要求高，激光加工系统必须有稳定均衡的能量输出和严格的加工轨迹跟踪能力。采用精细聚焦直刻方式的激光加工器，很难实现上述要求，而采用掩膜加工方式，如果以准分子激光器为光源，价格昂贵，本文尝试采用Nd:KGW固体激光器为光源，设计高性能价格比的激光掩膜加工系统。本文首先回顾了国内外激光加工技术、激光电源的发展，分析了激光加工技术和激光电源的现状。通过仿真与试验，设计了脉冲固体激光掩膜加工器的电源电路及控制系统，并详细地分析了它的工作原理。脉冲固体激光电源为氙灯提供能量，氙灯是激光的泵浦源，它燃烧发光激发工作物质Nd:KGW 产生激光，因此激光电源的性能直接影响到激光光束的质量。本文设计的脉冲固体激光器电源系统由以下几部分组成：充电回路，放电回路，泵浦灯的触发电路和预燃电路。文中分别针对这几个组成部分进行了详细论述。充电和放电回路是电源系统的核心，本文对其进行了从原理分析到具体参数选择的详细论述。由于本次设计的脉冲激光电源是用于小功率的激光微加工，设计中采用了可控倍压整流电路作为其主电路形式，通过电压反馈控制实现恒压输出。此电路结构简单，工作可靠，成本低廉,是脉冲固体激光电源中广泛使用的一种电路形式。在放电控制方面，设计了放电能量逐脉冲计算电路，输出结果与给定电压比较决定泵浦脉冲宽度。根据氙灯闪光时电流瞬时值大的特点，本文设计了相应的保护电路，以防放电回路器件损毁。预燃技术在脉冲固体激光器中的应用增加了泵浦灯触发的可靠性。本文设计了一种新颖的触发预燃电路，触发与预燃所需高压均由泵浦电源提供，无需设计独立的触发预燃高压电源。预燃电路包含两条回路，分别工作在触发状态和稳定预燃状态，在氙灯气体引燃时为保证辉光放电稳定，触发预燃回路开通，氙灯进入稳定预燃状态后，切换预燃回路至稳定预燃回路，这样既提高了触发的可靠性又减小了预燃损耗。 <WP=65>用于加工的激光束要求有较高的能量密度，本系统中应用了激光调Q技术，将泵浦能量压缩至十几纳秒放出，产生高能量密度的激光巨脉冲。本文设计了完整的激光调Q系统，并对调Q系统的各组成部分设计过程进行了分析。脉冲固体激光掩膜加工系统的运动执行机构为在同一平面上转向垂直的两台步进电机，通过电机在X,Y方向的差补运动光束完成一个15×15mm平面上的扫描。系统中使用两片80C196KC单片机分别对激光泵浦和光束扫描运动进行控制。文中详细绘制了单片机的主程序流程图及相关子程序流程图，并结合流程图分析了程序设计思想。本文通过实验验证了对电源系统和加工控制系统的设计和分析。实验表明电源系统工作稳定可靠，在网压变化和负载波动时能实现恒压控制，系统泵浦能量、频率可调，扫描频率可调，加工控制运行正常。更多还原

【Abstract】 Laser has a lot of advantages such as good directionality, high energy and monochromaticity. It has been lay store on and widely used since it was discovered in the world. Especially in machining industry, Laser machining is taking more and more percentage with the growth of laser machining market. In this circumstance, studying on the design of laser machining system with high reliability, high stability, and high intelligence is very important for the developing of laser machining technique. Since the precision prescribe is strict, laser machining system must output stable energy and have precise machining trajectory tracking ability. Machining with the delicate focusing scratch system can hardly reach these requirements. Mask machining system can easily reach the requirements, but the system will be very expensive, when semi-molecular laser machine is used as the laser source. In order to get a mask machining system with high ability price rate, a Nd:KGW laser is used as the laser source in this design.This dissertation firstly reviews the development of laser machining and laser power, analyzes the current laser machining status and laser power technique. Then the pulsed solid state laser power and mask machining system is designed through simulations and experiments. And the system working theory is also analyzed. Power supply system provides flash energy to Xe lamp. Pumping of Nd:KGW laser rod is provided by Xe lamp. Pulse solid laser power directly affects the attribute of laser. The pulse solid laser power consists of charge circuit, discharge circuit, trigger circuit and simmer circuit. All these circuits are analyzed and discussed in the dissertation.Charge circuit and discharge circuit are the most important circuits in pulse solid laser power. Theory analysis and parameters selection are concretely described. Since the power supply is used for low power laser micromachining system, double voltage regulator is applied as the main charge circuit. Constant voltage output is realized through voltage feedback control. The power system has simple circuit topology, high stability, low cost price. And it is a widely used power supply mode in pulse solid laser power. As an important component of pumping energy control circuits, the analogue operation circuit can calculate each pulse pumping energy. The outcoming <WP=67>signal compares with a threshold voltage to control the pumping pulse width. When the lamp is flashing, a huge current pulse exists in the discharge circuit. To keep the components from overheating protect circuit is designed.The application of simmer technique makes it reliably to trigger the pumping lamp. A new style of simmer circuit is designed. The trigger and simmer voltage is not provided separately, but provided by the lamp pumping power supply system. The simmer circuit consists of two branches. One branch circuit works when the lamp is ignited. Another works after the ignition. When simmer current becomes stable and continuous, the first branch is closed, the second branch keep the simmer current in a small value. This switching operation can not only enhance the reliability of trigger but also reduce the simmer loss. The laser beam used for micromachining must have high energy density. Q- switching technique is applied. By releasing the pumping energy in about a decade nanoseconds, huge energy density beam can be achieved. The integral Q-switching equipment is designed, and the design of each components of the equipment is described. The machining operation mechanism of Nd:KGW pulsed solid state laser mask machining system consists of two step motors, which rotate vertically in the same face. By the alternately steering of the two step motors, the laser beam can scan over a 15×15mm surface. Two 80C196KC microchips are used to control the pumping and scanning course in the system. The float graphs of main programs and subprograms are shown concretely in the dissertation. The programs’ design idea is analyzed associate with these float graph. The design and analysis are p更多还原