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目的:精密冲压工艺过程中环境变量的波动导致工件出现破裂和皱褶等缺陷。探讨精密冲压工艺过程中环境变量(工件材质、冲压速度、压力、模具间隙和温度变化等)对冲压质量的影响,研究适应性工艺设计方法,提高精密冲压工件的质量。创新点:1.通过马尔科夫模型方程,推导出环境变量与精密加工波动公差之间的关系;2.建立试验模型,成功模拟适应性冲压工艺过程。方法:1.通过实验分析,推导出冲压过程中的晶粒流动和强度变化对成型零件的尺寸公差波动产生较大的影响(图2和3);2.通过理论推导,构建环境变量与加工波动公差之间的关系,得到适应性的工艺参数调节方案(公式16);3.通过仿真模拟,运用适应性设计方法在精密冲压过程中对工艺参数进行适应性调节,验证所提方法的可行性和有效性(图5)。结论:1.精密冲压过程中工艺参数需要根据不同的环境变量进行调节;2.环境变量与加工波动公差之间存在映射关系,运用隐马尔科夫模型实现关联表征;3.运用适应性设计方法对精密冲压工艺参数进行调节,加工波动公差明显减小,工件质量得到提高。
OBJECTIVE: Fluctuations of environmental variables in the precision stamping process lead to the defects of the workpiece such as rupture and wrinkle. The influence of environmental variables (workpiece material, stamping speed, pressure, mold clearance and temperature change) on the stamping quality during precision stamping process was studied. The adaptive process design method was studied to improve the quality of precision stamping workpiece. Innovations: 1. Through the Markov model equations, the relationship between environmental variables and tolerances of precision machining is deduced.2. The experimental model is established to simulate the adaptive stamping process successfully. Through experimental analysis, it is deduced that the variation of grain flow and strength in the stamping process have a great influence on the dimensional tolerance fluctuation of the molded parts (Figures 2 and 3) .2. By theoretical derivation, (16); (3) Through the simulation, the adaptive design method is used to adjust the process parameters in the precision stamping process to verify the feasibility of the proposed method Sexual and Effectiveness (Figure 5). Conclusion: 1. During the precision stamping process, the process parameters need to be adjusted according to different environmental variables; 2. There is a mapping relationship between environmental variables and machining tolerances; Hidden Markov model is used to realize correlation characterization; 3. Precision stamping process parameters to adjust the processing tolerance is significantly reduced fluctuations in the quality of the workpiece has been improved.