本研究主要針對皮秒雷射劃線搭配 CO2 雷射切割之方法進行探討，藉由統整應力試驗、模擬數據以及實際實驗之結果，找出能切割成功的上下應力臨界門檻，並探究此範圍外會導致切割失敗之原因，以期減少測試的成本，透過模擬便可推測切割成功與否。在皮秒雷射刻劃切割線方面，同計畫的夥伴透過對改質前後的玻璃進行各種應力試驗及模擬分析，彙整後得出皮秒雷射改質後玻璃破裂所需的應力強度，即欲使 CO2 雷射切割成功的最小應力臨界值；另外，我們再由模擬 CO2 雷射切割的情況，觀察於切割過程中玻璃內部的溫度場及應力場變化，並與工研院夥伴實際實驗的結果相互驗證，發現應力臨界門檻的最大臨界值；綜上所述可以整理出玻璃可破裂的應力大小應介於 30~70 MPa 之間。
於應力場方面，藉由觀察最大主應力的分佈，合理推論出此製程中熱應力導致玻璃破裂的物理機制。再由模擬中對雷射參數：光斑尺寸、功率和移動速率進行調整，歸納並進行定量分析，找出雷射參數變化對結果造成的影響。除此之外，由溫度場的變化中可推導出一適用於此製程的熱擴散公式，並以結果驗證其可行性，接著以此計算式及熱傳概念建立用以預測最大溫差之數學模型，再續以熱膨脹之物理概念推論出最大主應力預測模型，其中我們發現最大溫差以及最大應力會與?成正比，與?^3/2、?^1/2成反比。
目標於利用雷射參數即可以推導之數學模型有效地預測出雷射產生的熱應力大小，並配合玻璃破裂之應力門檻，便只需要透過數學計算即可知曉雷射切割的成功性，除此之外，亦可以藉此方式提升製程的效率。

In this study, we analyze a process of laser glass cutting, in which the glass first is scribed with periodic micro holes by a picosecond laser, and then split by a CO2 laser. In particular, the thermal stress associated with the heating of the CO2 laser is numerically calculated. Especially, the distribution of the maximum principal stress in the glass is examined because it is the major physical mechanism that splits the glass. The objective is to determine the most efficient combination of system parameters that can be used to complete the process, by combining our numerical results with the results of the residual stress due to material modification in the glass by the picosecond laser, which our collaborators help provide. The aforementioned system parameters include the laser spot diameter D, power P, and cutting speed v, and their effects on the maximum principal stress in the glass are systematically studied in this work. In addition to purely numerical computations, a scale analysis also is carried out here, which indicates that the maximum temperature difference and maximum principal stress in the glass both are proportional to P, and inversely proportional to D^3/2 and v^1/2 within the range of laser parameters used in the experimental process, where P is less than 150 W, v is 7 ~ 300 mm/s, and D is 1.0 ~ 4.0 mm. Moreover, these scaling laws correlate the numerical results very well. In addition, the upper and lower critical stress thresholds of 30 MPa and 70 MPa between which the glass can be successfully split, as observed in experiments, are confirmed by the numerical results obtained in this work and that provided by our collaborators.

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