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A study of pulsed laser characteristics and shape of process effect on solder joints
Laser spot welding
|Issue Date: ||2017-07-03 20:04:22 (UTC+8)|
|Abstract: ||本研究以不同厚度組合之AISI 304不銹鋼薄板搭配不同之Nd:YAG 雷射點銲參數對搭接試片進行點銲實驗，探討雷射參數對銲點外觀及機械性質之影響。過程中除了藉由改變雷射的脈衝頻率與電流的大小，也嘗試採用雙重點銲方式來進行。另外，針對試片清洗、改善銲點噴陷現象以及接合面的間隙效應也在本實驗研究範疇中。雙重點銲頻率大小會改變銲點的外觀及抗剪強度。點銲頻率增加會使銲點表面直徑(d2)與接合面直徑(d1)降低。而酒精清洗後的試片其抗剪強度則稍微增加，至於銲點噴陷現象，以正離焦方式進行第二次的雷射點銲可有效獲得改善，其平均改善效率48%。搭接試片的間隙會因雷射熔融之金屬液向下填補，造成銲點表面直徑(d2)降低。實驗結果顯示間隙值在0.1~0.3 mm範圍內，抗剪強度可獲得提升。
In this study, the AISI 304 stainless steel sheets with various thickness combinations were subjected to different Nd: YAG laser spot welding parameters and discuss the influences of laser parameters on the appearance and mechanical properties of welding joints. Except changing the laser pulse frequency and current, also try to use double spot welding to carry out. In view of the effects of bonding surface cleanliness, the jetting of improving the welding joints and the gap of bonding surface are also the investigated fields in this experiment.The frequency of double spot welding changes the appearance and shear strength of welding joints. Increasing the frequency of double spot welding reduces the spot diameter (d2) and the joint surface diameter (d1). However, the shear strength is slightly increased as for the alcohol wipe the test piece. The second laser spot welding by defocusing method can be effectively improved the phenomenon of welding joint, which has an average improve efficiency of 48%. The gap of lap test piece will be filled down by the laser melting of the molten metal. The surface of the welding joint causes a decrease in diameter (d2). The experimental results show that the gap value in the range of 0.1-0.3 mm can improve the shear strength.
|Appears in Collections:||[機電工程系(所)] 學位論文|
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