If you're looking to add a new dryer to your garment-printing shop, this article can help you narrow your selection.
In gas dryers, one or more burners generate heat, and a powered blower takes in filtered air and pushes it through the burner chamber. The heated air then enters a plenum chamber and makes contact with printed garments by way of strategically placed jet nozzles or air knives that concentrate and direct the hot air. Some manufacturers offer recirculation systems to boost efficiency by keeping heated air in the dryer. A portion of the circulating air is exhausted as fresh, filtered air is introduced to the system. A few dryer models are configured so that the operator can adjust the rate of intake and exhaust to best match the application at hand. Piping the dryer's exhaust to the outside is an important part of maintaining a safe working environment for employees.
Analog controls (Figure 3) are available on both gas and electric dryers. Analog control systems can be as simple as an on-off switch and a dial that controls belt speed. The next step up is a combination of analog and digital controls. The most common setup is digital temperature control and analog belt-speed control (Figure 4). Digital control systems (Figure 5) may include alphanumeric readouts and electronically programmed temperature and belt speed, and some models come with displays and touchscreen interfaces (Figure 6).
A large IR dryer or gas dryer with either a combination of analog/digital or completely digital control will help you keep up when job sizes increase (Figure 7). These types of controls tend to be more sensitive, accurate, and responsive, allowing users to carefully tune temperatures, belt speeds, and other operating parameters to effectively deal with large runs and jobs that involve more demanding inks, such as glitters, metallics, and high-density formulations. You may also find that precision controls allow you to successfully use your dryer to cure a variety of screen-printed products other than textiles (Figure 8).
The less sophisticated the controls, the more important it is that you conduct tests to determine what temperature settings and belt speeds are required to cure your prints. Use temperature probes to monitor heat levels, and perform rub and wash tests on the printed garments to ensure that the ink film is completely cured.
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