During the metallizing process thin film web is appressed with the cooling drum, the cooled drum can reduce the web temperature after that the evaporated aluminum is deposited onto it. This method is the most widely applied in vacuum aluminization. However, such an aluminizing process results wrinkles on the web surface due to the high temperature up to 1700 ℃ on the deposition side and low temperature caused by the drum on the other side. Furthermore, as the web surface is wrinkled, uncoated web can be forced to move, light line problem occurs therefore.  Light line is one of the most intractable difficulties in metallization industry, to eliminating it, some modifications are attempted, such as the design of spread roll with larger radian or the optimization of film speed and layer thickness. Nevertheless, no significant improvement has been proven, meanwhile, new problems can result from these modifications, for example, spread rolls with larger radian can damage the film.

Gas wedge is applied in our drum metallizer for eliminating light lines and improving the quality of metallized film.