Design And Implementation Of Laser Marking Machine’s Motion Controller

Laser marking technology is a new processing technology which is developingrapidly after laser heat processing technology, laser welding technology, and lasercutting technology. Its principle is to use laser beam with high energy density to makethe surface of target vaporizing quickly, forming the grooves, and thereby takingshape the marking pattern on the surface of target. Compared with the traditionalmode of marking, laser marking technology has many advantages, such as nopollution, high speed, good quality, no wear, and so on. In addition, the embeddedsystem has the character of low cost, high reliability, high integration. This projectgives full play to the advantages of both, and puts forward the design scheme ofembedded laser marking machine.Firstly, this paper introduces the research status of laser marking technology athome and abroad, and introduces the working principle of laser marking machine andits system composition. Combined with low cost and high performance advantage ofthe embedded control system, this topic puts forward the design scheme of proposedlaser marking machine controller based on the STM32. Through the analysis of thefunctional requirements of laser marking machine, the project choosesSTM32F103ZET6which is designed by STMicroelectronics Company as the maincontrol chip, and selects the digital galvanometer scanning system which is of highprecision, high speed, strong anti-jamming capability to control optical path, andselects pulse fiber laser with high stability. This project has completed hardwarecircuit design and software design of the laser marking machine controller accordingto the scheme of system. In this system, the controller communicates with the PCthrough Ethernet. For this, the controller uses the high-speed Ethernet chip DM9000Aas the network driver chip, and transplants uIP protocol which has a little code but allopened, and its basic function is complete. After testing, the transmission speedreaches2MBPS. For the marking data from PC, the controller first stored them to theexternal SRAM, then read them from the SRAM and parsed into the data needed bythe galvanometer scanning system and laser. After that, the controller transmitted thenew data to the galvanometer scanning system by the way of SPI, at the same time,controlling the laser on or off, so as to realize the target graphics engraving on thesurface of the object. What’s more, this article analyzed the mathematical model of the galvanometer scanning system and the causes of marking graphics geometricdistortion. Then a correction method of quadratic polynomial fitting was adopted bythe controller. The comparison of marking rectangles between before correcting andafter correcting turned out that, after using the correcting method, the correction effectof graphic geometric distortion was obvious.Through testing for many times, the system is able to draw simple graphics,input characters, and import PLT vector files. And most importantly, the system cancomplete the whole process of marking with high speed and strong stability, and theresult is good.