Real-time Monitoring And Impact Evaluation Of The Ultrafast Laser Micromachining

In recent years, laser drilling and laser cutting in the proportion of industrial applications is growing rapidly. But no matter what type of processing, there is a drawback, that is, to produce a certain amount of waste. In the laser processing, only by monitoring the production process and control the special features of the production parts to ensure the high quality of the parts and components. To achieve reliable monitoring, the monitoring system must be able to accurately reflect real-time conditions in the area of the laser and material role or neighborhood. This means that the monitoring process must be non-contact operation to ensure that does not process the interference.This thesis focused on real-time monitoring of ultrafast laser micromachining technology. Laser scanning micro-hole aperture measurement by using coaxial monitoring method was achieved. Firstly, the monitoring signal of the laser micro-machining, monitoring methods and monitoring tools were discussed comprehensively:Secondly, according to the actual optical path of laser processing, the coaxial monitoring optical path was designed.According to the aperture indicators of the processed micro porous; the various parameters of the imaging lens group were calculated. By using the lens system of combination positive and negative lens the monitoring optical path was shortened. And a set of imaging relay lens group were designed by using optical design software zemax, Finally, the experimental optical path is build and get images. Through the image measurement method the aperture size of the laser processed micro porous was detected. Including the scale factor calibration of CCD imaging system, and the noise removal, thresholding segmentation of the images, and ultimately by the least squares method for circle fitting, the size of the microspores was calculated.In addition, because of the use of the focal spot energy interact with the work piece in laser processing, during the processing; the work piece must be set in the focal plane of the focusing lens. The monitoring system was designed in this thesis, just with an indicator light, can also achieve the machined surface and the focus position deviation measuring. And through feedback mechanisms can achieve the purpose of automatic focusing.