Research On Laser Cutting Of Carbon Steel Based On Thermal Analysis And Image Recognition

Laser cutting technology,as a new technology,has been widely used in the manufacturing industry,especially in the field of plate processing.Using fiber laser cutting machine to process thin carbon steel plate can realize the plate deformation is small,the processing precision is high,the installation is convenient,not only reduces the production cost,but also improves the production efficiency.However,in the actual production,when large-scale cutting of thin carbon steel plate,especially when cutting complex trajectory,heat concentration is easy to occur,which makes the plate bend and deformation,which leads to slag hanging and area ablation after the cutting.Therefore,it is very important to simulate the laser cutting process and determine the optimal process parameters suitable for plate cutting.However,in the actual production,when the thin carbon steel sheet is cut on a large scale,especially when the track is more complex,heat concentration is easy to appear,which makes the sheet bending deformation,and then leads to the slag hanging and ablation defects after the cutting is completed,affecting the cutting quality.Therefore,through thermal simulation analysis and experimental verification to determine the optimal process parameters of laser cutting thin steel plate,has a very important guiding significance to the actual production and processing.The key factors affecting the cutting quality of laser cutting thin steel sheet are determined by thermal simulation analysis and experimental exploration,such as cutting speed,auxiliary gas pressure and sheet thickness.Aiming at the three key factors,the thesis to determine the laser cutting of Q235 carbon steel thin plate,the optimal processing technological parameters and cutting two requirements of product quality,improve the physical process of laser cutting board to carry on the simulation,analysis of the cutting temperature field distribution and heat transfer law in the process,optimization of process parameters,reducing plate or uneven distribution of temperature field and local over heat Combined with the simulation results,the experimental cutting was carried out to explore the optimal process parameter combination in the actual machining process.Through the application of image recognition algorithm,the defects of laser cutting plate were identified and the cutting quality was quantified,and the quantitative evaluation and optimization process of laser cutting product quality were established,which provided support for the realization of real-time and efficient evaluation of laser cutting quality online.The specific work is as follows:(1)Combined with the principle of heat transfer,the model of laser cutting 2mm thick plate was established by using ANSYS software to analyze the influence of different process parameters such as cutting speed and plate thickness on the temperature field distribution,obtain the temperature field distribution cloud map in the cutting process,and analyze the transfer law of temperature and energy.(2)The laser cutting technology of 2mm Q235 carbon steel was studied by using SFL-3015 C high-power fiber laser cutting machine combined with the theoretical analysis law and the comparative analysis method of experimental parameters.Firstly,the simulation results were verified by single factor analysis method.Secondly,the influence of cutting speed on slagging height and auxiliary gas pressure on slagging height were studied by means of control variables when the auxiliary gas pressure was constant.Finally,based on the slag-hanging height of the plate after cutting,the range of process parameters that meet the requirements is preliminarily determined by comparative analysis.(3)The image recognition system was established to identify and analyze the ablation area of plate cut out according to the requirements of each process parameter.The acquired image is enhanced to highlight the defect area of the product;Differential method is used to sharpen the image to reduce the fuzzy boundary and highlight the defect information.Based on the improved morphological feature extraction algorithm and the improved eight-domain target tracking algorithm,the defects in the ablation area of laser-cut plate surface were segmented and extracted by MATLAB simulation tool.The eigenvalue of defect size was calculated by Hough transform.Through the comparison of eigenvalues,the optimal combination of process parameters in line with the actual production of enterprises is determined.The experimental results show that this method can successfully extract the defect characteristics of laser cutting products,realize the detection and evaluation of various defects in the laser cutting process,and provide technical support for the further realization of online non-contact efficient cutting quality detection.