| 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 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...
|
PDF Full Text Request