Optimisation of laser fading process in denim trousers: An industrial scale approach

Abstract

Colour fading with laser application has now become a well-known and frequently used process in the denim industry. However, in practice, high strength losses and even tears may occur in the trousers as a result of incorrect or excessive laser application. In this study, the effects of resolution (dpi) and pixel time (μs), which are the two main parameters of laser colour fading, and also the effects of two-passage laser treatments on colour fading and fabric strength were examined statistically and optimum conditions were determined. When the results of the studies are evaluated in general, it can be said that as the resolution (dpi) increases during the laser process, the colour fading effect increases, but when it is above the 31 dpi value, the strength loss increases excessively. As the second important parameter, the pixel time, increased, the colour fading effect increased. When the time exceeds 80 μs, there is a marginal increase in the strength loss value. Furthermore, it was observed that colour fading (%) values increase if laser process is applied in two passages, but in this case also the tear strength loss increases. It can be said that optimising the laser processing conditions in enterprises according to the product type (fibre content, weight, etc.) is a more accurate approach in terms of both the fading performance to be obtained and product quality. For 11.25 ounce trousers made of 95.3% cotton/3.4% polyester (T400)/1.3% elastane used in this study, it can be said that laser application could be made in two passages if necessary for obtaining high colour fading, however it should be noted that resolution and pixel time should not exceed 31 dpi and 80 μs, respectively. Provided that resolution and pixel time does not exceed 31 dpi and 80 μs, respectively, they can be changed depending on the degree of colour fading needed.