Print quality optimization in screen printing by AM and FM screening using Taguchi's Grey Relational Analysis technique

This is an experimental and statistical approach to assess the impact of AM and FM screen ruling in screen printing under the condition such as printing of a test target on both coated and uncoated paper with three different types of screen mesh count. The change in print quality according to the screen mesh count are focused here, because the screen mesh count is one of the key elements in screen printing that influences the ink flow through the mesh as well as the excellence of stencil image or halftone dots over the mesh. Under three different screen mesh count, the impact of AM and FM halftone in the print quality on both coated and uncoated paper grades are evaluated in the analysis part. The print quality assessment parameters taken as solid ink density, dot gain, hue error and print contrast at 30%, 50%, & 70% tonal areas of the print. Twelve different combinations of input variables such as coated and uncoated substrate, AM and FM halftone dots, 100 lpi, 120 lpi and 140 lpi screen mesh counts etc. are employed at different print trials. The print quality assessment and ranking of each experiment are done by Taguchi’s Grey Relational Analysis, which is a best method to implement in the decision-making process of quality control.