不锈钢薄板光纤激光切割工艺研究

发布时间：2018-04-07 18:08

本文选题：不锈钢薄板　切入点：光纤激光切割　出处：《济南大学》2017年硕士论文

【摘要】：光纤激光切割有其独特的优势:切割质量好、切割效率高、切割速度快、非接触式切割、范围广、清洁安全无污染,在市场中短短几年内得到广泛认可。国内小品牌层层叠出,国内目前激光切割技术缺乏创新,由于工艺参数复杂,在大多数工厂中技术人员都是依据经验调整参数,工作效率低下,而且众多企业没有行业标准,产品质量得不到严格的把控,良莠不齐。本文在研究国内外激光切割工艺现状的基础上,建立了ANSYS有限元模型,对激光切割不锈钢薄板时温度场分布、应力场分布及它们的变化规律做了仿真研究。并且做了现场切割实验,通过测得的切割指标数据与仿真分析做了对照,验证了仿真分析的可靠性,总结了切割规律,得到切割不锈钢薄板的最优参数。具体内容如下:首先,根据能量传递建立激光切割数学模型,通过ANSYS仿真软件建立了激光切割不锈钢过程的有限元模型,利用APDL编程语言得到温度场分布及变化规律。通过间接法求出应力场分布及变化规律并添加了生死单元技术,实现了随着切割头移动金属融化并被吹除的过程仿真。发现在切割头前进方向温度和应力都存在集中现象,激光传递在板材内部呈斗形照射,且光纤激光切割存在光束集中现象。其次,在有限元模型温度场分析的基础上,通过APDL编程语言改变参数,分别分析了切割速度、切割功率及板厚变化下对温度场的影响规律,并结合机理分析了其对切割指标的影响。研究得出切割速度过快、功率过小、板材过厚时都会使材料接收的温度达不到其熔点,底层不能得到完全融化从而导致工件切不透,另外速度过慢时,切缝内壁不断得到照射,使得熔融的金属在来不及被辅助气体吹走的情况下,会导致挂渣形成,功率过大会使切割区温度急剧增高,融化半径变大导致切缝变宽及融滴形成,板材过薄时切缝变宽,切缝不规则。最后,利用光纤激光切割机对1mm、2mm、3mm厚度的304不锈钢进行切割,测量挂渣量高度、粗糙度,并利用超景深显微镜测量条纹间距和切缝宽度。实验结果验证了仿真分析的可靠性。并通过响应曲面法得到焦点和功率是影响挂渣量的主要因素;功率和板厚是影响切缝宽度的主要因素;功率和焦点是影响粗糙度的主要因素;气压和功率是影响条纹间距的主要因素。在仿真和实验研究的基础上,最终得到切割板材的最优参数。同时利用最优参数作为仿真分析的工艺参数代入进行分析,结果表明仿真分析模型具有一定的可靠性。
[Abstract]:Fiber laser cutting has its unique advantages: good cutting quality, high cutting efficiency, fast cutting speed, non-contact cutting, wide range, clean, safe and pollution-free, has been widely recognized in the market within a few years.Domestic small brands stacked up, domestic laser cutting technology is currently lack of innovation, because of the complex process parameters, in most factories technical personnel are based on experience to adjust parameters, low efficiency, and many enterprises do not have industry standards,The quality of products can not be strictly controlled, the good and bad are mixed.Based on the research of laser cutting technology at home and abroad, the ANSYS finite element model is established, and the temperature field distribution, stress field distribution and their variation law are simulated.The field cutting experiment was done and the cutting index data was compared with the simulation analysis. The reliability of the simulation analysis was verified and the cutting rule was summarized. The optimal parameters of cutting stainless steel sheet were obtained.The main contents are as follows: firstly, the mathematical model of laser cutting is established according to the energy transfer, the finite element model of laser cutting stainless steel is established by ANSYS simulation software, and the distribution and variation of temperature field are obtained by using APDL programming language.The distribution and variation of the stress field are obtained by indirect method, and the birth and death element technique is added to simulate the process of melting and blowing the metal along with the movement of the cutting head.It is found that the temperature and stress in the forward direction of the cutting head are concentrated, the laser transmission is in the shape of a bucket inside the plate, and the optical fiber laser cutting has the phenomenon of beam concentration.Secondly, on the basis of temperature field analysis of finite element model, the influence of cutting speed, cutting power and plate thickness on temperature field is analyzed by changing parameters by APDL programming language.Combined with the mechanism, the influence of the cutting index was analyzed.The results show that when the cutting speed is too fast, the power is too small and the plate is too thick, the receiving temperature of the material will not reach its melting point, the bottom layer can not be completely melted, and the workpiece cannot be cut through. In addition, if the cutting speed is too slow, the inner wall of the cutting seam will be irradiated continuously.If the molten metal cannot be blown away by the auxiliary gas, it will lead to the formation of slags. If the power is too high, the temperature of the cutting area will increase sharply, and the melting radius will become larger, resulting in the widening of the slit and the formation of the melt droplets, and when the sheet is too thin, the slit will become wider.The slit is irregular.Finally, 304 stainless steel with a thickness of 1mm ~ 2mm ~ 3mm was cut by optical fiber laser cutting machine, and the slagging height and roughness were measured, and the fringe spacing and slit width were measured by using the hyper-depth of field microscope.The experimental results verify the reliability of the simulation analysis.Through the response surface method, it is found that the focus and power are the main factors affecting the slagging amount, the power and the plate thickness are the main factors affecting the width of the slit, the power and the focus are the main factors affecting the roughness.Pressure and power are the main factors affecting the stripe spacing.On the basis of simulation and experimental research, the optimal parameters of cutting plate are obtained.At the same time, the optimal parameters are used as the process parameters for simulation analysis. The results show that the simulation analysis model has certain reliability.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG485

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