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How to Optimize Your Flash Curing

(August/September 2017) posted on Tue Sep 12, 2017

Learn ways to increase your production while reducing cost, heat, and wasted energy.

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By Mark A. Coudray

Flash curing has been an essential part of textile and T-shirt production for over 40 years. Yet, for all its benefits, flash curing has become a Band-Aid many printers use to correct poor printing practices. It can be a great problem solver for novice printers: Flashing between colors seems to fix registration problems, ink build-up on the screens, and other technique-related defects.

The problem is, flash curing means heat, and heat is wasted energy. Besides being expensive, heat also affects mesh tension, registration, production speed, and the performance of subsequent colors in the print sequence. Overuse of flash curing leads to heat retention on the platen and the surface of the garment. The heat can’t dissipate into the environment, so it gets transferred to subsequent screens, where it can heat or gel the ink and lead to image defects. The substrate also absorbs the excess heat, which can be a disaster with sensitive fabrics. We always want to use the minimum amount of heat to get the job done.

Unfortunately, new ink systems and the mandate by some of the major brands to remove PVC from the formulations have dramatically increased the need for individual flashing between colors. High solids acrylic (HSA) water-based inks, for example, require flashing and a cooldown station after every color. This triples the number of heads required on a press. A conventional 16-color press now requires 48 heads plus load and unload stations. The energy usage and high capital cost of such very large oval presses with multiple flashes is considerable, even with high-volume production orders.

And it’s not just the inks: The technical nature of the fabrics we’re printing more often today also makes flash curing a critical control point in production. Materials like moisture-wicking polyester, performance apparel, stretch fabrics with Lycra, low-energy sublimated jerseys, and lightweight tri-blend yarns demand precise control of heat to achieve the right results. These substrates often have very narrow processing windows that result in high shrinkage, sublimation dye migration, or scorching if too much heat is applied or allowed to build progressively over time. (See Figure 1.)


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