Find out about the differences between IR and hot-air dryers and discover which features might be most useful to your operation.
Garment screen printers are used to two types of dryers on the production floor: infrared and hot air. Both dryers use a conveyor to transport garments through the curing chamber and use heat to set the inks on the garments (up to 330°F for plastisols). These are the only similarities between these two dryers. The dryers are otherwise very different in design, capacity, versatility, running cost, and level of investment. For starters, infrared dryers work with direct heat radiated from infrared panels to heat up the ink to a specific drying/curing temperature. Hot-air dryers use heated air blown over the garments to transfer the heat. Let’s look into the factors that set these two dryer designs apart and discuss the advantages, versatility, and possible limitations of each.
The infrared dryer
The Infrared, or IR, dryer uses electrically heated infrared panels mounted above the conveyor belt in a heat-insulated cover. As the printed garment passes under the IR panels, the radiated heat is absorbed by the ink and heated up to curing temperature. The drying temperature is regulated by the electric power to the element and/or by adjusting the height of the IR panels above the conveyor. The conveyor speed is also adjustable to set the correct drying time. The IR dryer is, by its nature, compact and simple in its design with few moving parts and is consequently a relatively inexpensive investment.
Ink considerations Water-based inks typically do not work well in an IR dryer because the dryer lacks airflow needed to drive out the water from the ink for a proper cure. Some infrared dryers use special IR panels with a small air-circulation fan that creates a moderate airflow to assist in drying. The drying capacity is reduced because water-based inks have a 50-100% longer drying time. The water must be driven out of the garment first before the ink can be heated to the final curing temperature.
Variations in drying temperature Due to the direct heat radiation, the drying temperature can be difficult to control and, therefore, may vary depending of what type of garment is used and the thickness of the print. Always test various dryer settings for best results each time you use any new type of garment or ink for the first time. This will minimize the risk of scorching the garment or under/over curing the ink.
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