Parametric Study of Gravure Printing for Electric Heaters

Gravure printing of silver electrode heaters on flexible substrates for consumer applications was investigated. Low cost PET and TPU substrates were printed on 300 mm web width gravure line. Printing process was optimized by print speed, ink viscosity and ink wetting interaction to substrate. Gravure printing was characterized by heater resistance measurements for process repeatability. Printing of mesh patterns was assessed at different speeds on PET substrate by using compatible ink diluted to 1800 cP. The measured resistance increases with increasing speed. At higher speed, ink spreading reduced and printing repeatability performed better. At printing speed of 1 m/m, ink smear appeared. The smear diminished as speed increased from 3 to 5 m/m. The effect of ink viscosity variation was studied by diluting the ink to 900 cP. Higher ink viscosity produced lower resistance and better performance. Printing on TPU substrates showed printing definition defects. Corona surface treatment on substrate had very little effect. Addition of ink additive greatly improved the printing definition by surface tension reduction.