Find out about the differences between IR and hot-air dryers and discover which features might be most useful to your operation.
On-board diagnostics An automatic diagnostic warning system is recommended for larger dryers and for larger facilities where many dryers are in operation. It constantly monitors all of the important dryer parameters, such as airflow, temperature, and heaters, and it gives an alarm automatically when there are any significant changes in a dryer’s operation and performance.
Modular design Modular dryer designs (Figure 2) allow the units to be upgraded by adding one or several more drying modules to meet any future demands for increased production capacity or changes in ink types.
The introduction of water-based inks created the need for two different sets of drying parameters, one retention time for plastisols and another for water-based inks. The retention times for water-based inks are often 50-100% longer. One wide dryer is often used to cure prints from two automatic garment presses, where one press is located on each side of the dryer’s inlet. In such a case, one can only run one ink type in either press at the same time. With the introduction of the split-belt dryer, where the conveyor belt is separated into two belts side by side, each with its own conveyor drives, it is now possible to run simultaneous production from two presses without any restriction as to which type ink is being used in either press.
The introduction of direct-to-garment digital printers with water-based inks called for longer drying times and longer dryers, 8-16 ft, which for many is a problem with floor space and handling. The digital printers are operated by only one person, and it can be time consuming to always have to go to the back of the dryer for sampling or collection. The return-belt dryer is designed with a second return-belt conveyor under the first conveyor. As the garment exits from the hot-air section on the top conveyor, it passes over a transfer section that moves the garment onto the lower return-belt conveyor that brings it back into the hot-air section and to the front of the dryer.
Digital garment printers often require controlled humidity and are therefore installed in air-conditioned rooms. Here, the return-belt dryer can be of great advantage and offer great savings because the dryer’s heating chambers can be installed outside the air conditioned room, leaving only the top and bottom conveyor belts on the inlet protruding through an opening in the wall towards the printer (Figure 3). A the return-split-belt dryer can serve two digital printers each using inks with different drying times.
The IR and the hot-air dryer are today mature designs with their specific differences in technology and capacities. Choosing one over the depends on your needs for versatility, size, and capacity. Are there any future developments to expect for the dryers within the garment industry? Well, here have been talks about UV inks for garments for a long time.
Sylve J.D. Ericsson is executive VP for Interchange Equipment, Inc., Passaic, NJ. He has more than 40 years of experience in development and technical sales of screen-printing machines and equipment for the international market. Ericsson is a Member of the Academy of Screen Printing Technology and holds more than 20 patents. He is a recipient of the prestigious Swormstedt Award for technical articles.
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