不銹鋼SUS304雷射深雕之數值模擬分析

Numerical Analysis of Laser Engraving on the Stainless Steel SUS304

周芳銘(Chou Fang-Ming)

指導教授 ： 張金龍

國立屏東科技大學/工學院/車輛工程系所/碩士(2007年)

https://doi.org/10.6346/NPUST.2007.00057

摘要

在模擬雷射深雕的過程中，當以高功率密度(5GW/cm2)的雷射投射於工件表面時，會產生極大的溫度梯度，而導致工件內部殘留應力的產生。本文以有限元素分析軟體ABAQUS，利用移動熱源之方法及網格移除技術來模擬雷射深雕加工過程中雕刻層周圍的溫度場，並透過順序偶合法分析其所造成的應力場分佈情形。整個數值模擬之模型是以不銹鋼SUS304作為材質，並以脈衝寬度、脈衝頻率、雕刻速度及不同雕刻程序作為研究參數，以探討各項參數對深雕溫度場與應力場所造成的影響。模擬結果顯示，當提升雷射之脈衝寬度、脈衝頻率時，將因預熱效果之提高而降低雕刻時所產生的熱應力；同時在相同脈衝寬度及脈衝頻率之條件下，提升雕刻速度有助於降低雕刻層周圍殘留應力的產生。最後，藉由改變不同雕刻程序，得知以單向橫向雕刻時，所造成雕刻層周圍之殘留應力值分佈較大；而以縱向雕刻時，刻除之表面有著最大的殘留應力值；而以雙向橫向雕刻時，雕刻層周圍所得到的殘留應力值最低且分佈均勻。

關鍵字

不銹鋼 ； 雷射深雕 ； 脈衝寬度 ； 脈衝頻率

並列摘要

In the process of laser engraving, the laser with high power density impinge on the work piece will increase the temperature gradient and induce the thermal stresses which usually cause the residual stress on structure. In this paper a finite element model with the moving heat source method and mesh remove technique was used to simulate the variation of the temperature field around the engraving region. Then, the thermal stresses and residual stress distributions can be calculated by the sequentially coupled thermal-stress analysis. The effects of parameters such as pulse duration, pulse frequency, engraving speed and engraving procedure on the engraving processing for the material stainless steel SUS304 will be investigated. The results showed that the laser with high pulse duration and high pulse frequency leads to a lower thermal stress due to the increase of the pre-heating effect. Moreover, at fixed pulse frequency and pulse duration, when the engraving speed increases, the residual stress around the engraving region will be reduced. Finally, changing engraving procedure will result in different residual stress.

並列關鍵字

stainless steel ； laser engraving ； pulse duration ； pulse frequency

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