Reliable laser micro-welding of copper
Reliable laser micro-welding of copper
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DOI：
10.1117/12.875033
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发表时间：
2011-02
期刊：
影响因子：
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通讯作者：
C. Ruettimann;U. Dürr;A. Moalem;M. Priehs
中科院分区：
文献类型：
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作者：
C. Ruettimann;U. Dürr;A. Moalem;M. Priehs
铜焊接的可靠性仍然是当今电子或医疗行业对点焊或接触焊的高要求的一个问题。由于铜在1微米波长下的低吸收率和非常高的导热性，即使是很小的表面污染也会导致焊接质量的剧烈变化。532 nm波长（倍频Nd：YAG激光）在室温下被铜更好地吸收。结合这两种波长并利用随着温度升高而急剧增加的吸收率，可以实现高效的点焊解决方案。采用Nd：YAG激光器热脉冲智能脉冲成形技术，显著提高了点焊的可靠性。本文讨论了一种解决方案，其中85 - 90%的1微米和10 - 15%的532 nm的辐射组成的Nd：YAG激光脉冲用于点焊80 - 300微米厚的铜带。实现了焊点直径变化低于6%与100%全熔透焊接相结合。与使用1微米辐射的常规点焊相比，工艺效率提高了两倍以上。
The reliability of copper welds is still a problem today concerning the high demands of spot or contact welding for the electronic or medical industry. Due to the low absorptivity at wavelengths of 1 micron and the very high thermal conductivity of copper, even small surface contaminations lead to drastic variations in weld quality. The wavelength of 532 nm (frequency-doubled Nd:YAG laser) is much better absorbed by copper at room temperature. Combining the two wavelengths and using the drastic increase in absorption with increasing temperature leads to an efficient spot welding solution. By the use of intelligent pulse forming with the thermal pulses of a Nd:YAG laser the spot weld reliability is improved significantly. This paper discusses a solution where Nd:YAG laser pulses composed of 85 - 90% of 1 micron and 10 - 15% of 532 nm radiation are used for spot welding of 80 - 300 micron thick copper ribbons. A weld spot diameter variation below 6% combined with 100% full penetration welding is achieved. The process efficiency is improved by more than a factor of two compared to conventional spot welding with 1 micron radiation.