本研究是利用Nd:YAG雷射對厚度0.5mm之439肥粒鐵不銹鋼薄板進行對銲銲接,探討雷射銲接參數對銲件之抗拉強度及銲道硬度之影響,並分別建立單一及多重目標品質之參數最佳化模式。研究之實驗流程分為實驗架構、單一及多重目標品質之參數最佳化分析等階段。首先利用田口法直交表進行實驗配置規劃,選定之雷射銲接參數為尖峰功率、脈衝頻率、脈衝寬度及銲接速度等4項。以抗拉強度及銲道硬度作為量測目標。經由田口法之平均數分析及變異數分析找出影響雷射銲接品質最重要的參數,以及最佳雷射銲接參數之組合。接著應用田口法與灰關聯分析,找出同時以抗拉強度及銲道硬度為多重目標品質之參數最佳化組合。結果顯示在單一目標品質參數最佳化分析中,可分別得到抗拉強度為母材強度的99.2%及銲道硬度為母材的99.1%。在田口法及灰關聯多重目標品質參數最佳化分析後,得知田口法及灰關聯多重目標品質參數最佳化分析和田口法單一目標品質參數最佳化分析所得參數最佳化組合結果相同,如此可確保分析的準確性。同時建立抗拉強度與銲道硬度趨勢之關係式,如此即可藉由測量銲道硬度來評估抗拉強度,對相關製程可提供一種更為簡便之品管檢驗模式。
This study is focused on the use of Nd: YAG laser for 439 ferrite stainless steel sheet in butt welding process, such that the effect of each laser welding parameter for the tensile strength and the weld hardness are investigated. Then two single and a multiple optimization models are established. An experimental work is associated with those optimization models in this study. Firstly, an orthogonal array of Taguchi method is used arrange experimental tests. The selected laser welding parameters are peak power, pulse frequency, pulse width and welding speed. Tensile strength and hardness of the weld parts are measured. The average and variance analysis of the Taguchi method are adopted in order to identify the most important laser welding parameter and the best combination of laser welding parameters. A gray relational analysis is used in order to find the optimized parameters combination in a multiple model. The results showed that in the single objective 99.2% in tensile strength can be obtained and 99.1% in weld metal hardness is achieved. In order to ensure accuracy of the analysis Taguchi method, associated with Gray relational analysis for the multiple objective to find the optimization parameters, has been performed and compared with the single objective model results. At the same time the trends for the relationship between hardness and tensile strength of the weld is developed. As a result, the related process can provide a more convenient mode of quality control inspection.