Recently in automobile industry, improved vehicle crash resistance and reduced CO2 emissions have been increasingly called for. In order to achieving those objectives, auto makers have invested heavily in researching related technologies. Research has shown that the tailored weld blank process is an effective way to increase productivity. This paper reports on study results that enable 20% faster weld speeds in actual production. This was achieved by actually defining the optimum blowing conditions of the assist-gas used to improve the quality of the laser weld.