Davis explains how flash units can influence productivity and describes problems you'll see when they fail to keep their cool.
By Rick Davis
Those of us who have been in the garment screen-printing business for a while know that flash curing during the printing process was, at one point in time, a specialty application. But today, the flash unit is a tool as common to the process as the screen itself. Be that as it may, there are still parts of the garment-printing process that can make or break a printer's day when they're not clearly understood. In this installment, we will review the different considerations associated with flash curing during the garment-printing process, as well as the way in which flash-cure units and drying systems work together.
In previous columns, I have mentioned the fact that many printers attempt to flash at temperatures that are detrimental to the process in the name of productivity. It is true that fast flashing times, specifically on automatic presses, require a higher temperature. The trick is to determine how fast you can properly flash the printed ink film without overheating to the point of damaging the underbase.
The best flash units offered today for controlling the ink-film temperature during the flash-curing process are quartz flash systems that reach a specific temperature in a short period of time and cool down immediately. These units offer a greater degree of control than most other flash setups. You also can use what are called black-panel IR flash units. Their specific temperature-control settings offer the next best degree of control.
Another option available to you is the black-panel unit that has no temperature setting and simply runs when you flip the on/off switch. The only real way to control or adjust these types of units is to simply raise or lower the height of the unit from the platen or garment surface. This method of adjustment poses the greatest challenge as you typically can only decrease the flash time as your platens heat up after printing for a period of time. Only you can determine which system will work best for your shop, but I think it's very important in the long run to have the ability to adjust your temperature and production proceeds.
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