An introduction to dye sublimation heat press process
Unikonex service department always get a question from client about why the unikonex cutting system sometime can not recognize the contour line for accurate cutting, after troubleshooting, we found the key issue is because of design nesting problem and dye sublimation quality. Therefore, here present an introduction to dye sublimation heat press equipment.
Whether it’s printing colorful fashion or sportswear, customized pattern T-shirt or outdoor wear, or even aluminum photo panels, dye sublimation is an popular choice of embellishment technology.
Printer is only a start, once you’ve printed your design onto a piece or roll of transfer paper, you need to transfer the design to your fabric, textile or any other materials. This process is combination of heat and pressure to make the solid dye particles which on the transfer paper to change into a gas (sublimates), so that it separates from the paper and is permanently bonded to the polyester threads or coating.
So what are the options of dye sublimation equipment? And which option will be best suitable for production requirements?
Flatbed or Rotary
There are three types of heat press for dye sublimation printing: 1- flatbed (for pieces to pieces), 2-Rotary (Calender) (for roll to roll), the third option is a rotary press with a flat automated feed table at the front (sometimes referred to as a ‘Sport’ press, as it is popular for printing sportswear panels/pieces).
Flatbeds comprise a table (platen/shuttle) onto which the substrate (for example, a T-shirt or cut panel) is positioned. A sheet of printed transfer paper is placed on top of the substrate. The table transports the substrate and paper under a platen that is heated to a given temperature, depending on the substrate. The heated platen is brought into contact with the transfer paper under sufficient pressure to cause the dyes on the paper to sublimate and transfer to the polyester substrate underneath.
Flatbeds with twin tables are generally chosen for pieces to pieces application . While an item is being pressed and sublimated on the first table, the operator can be positioning the next item to be printed on the second table. This avoids delays between each cycle and ensures that the press runs continuously, maximizing production. If your budget is limited or you have relatively low volume production, then a single table press is an affordable, alternative.
Roll Application
If your sublimation printing operation needs high volume printing of textiles, sports- and fashion wear, or you wish to print long lengths of substrate (for example, banners and flags), then you’ll want to consider a rotary press(Calender). Calender is more expensive than flatbeds, depending on the individual press’s size and spec, but they also offer much faster production speeds for mass production.
Rotary presses have a cylindrical felt covered drum, which is filled with oil. The oil is heated to the required temperature (200°C) creating an even and stable heat across the entire width of the drum. For roll-to-roll printing, rolls of the substrate and printed transfer paper are transported together around the heated drum, remaining in contact with the drum for a given length of time. A roller is used to apply tension to the tubular felt, which in turn applies pressure to the substrate and paper, holding it against the heated drum to facilitate the sublimation process. Separate rollers may also transport ‘protection paper’, which is used to prevent any excess gas that doesn’t sublimate into the substrate from transferring to the felt on the drum, (which could lead to unwanted transfer of the dye back onto the roll of substrate).
Standard features of a rotary press, include a fabric un-winder, tensioning device, contact-winder for the printed substrate, an un-winder and winder for the printed paper, and an un-winder and winder for the protection paper, plus a built-in cool-down timer, which also increases productivity.
When choosing a rotary press the main consideration are the diameter and the width of the drum. Drums can vary in diameter from 20 cm to 3 m; and the wider the diameter of the drum, the higher the press’s production speed. There is also a wide range of drum widths available, from 400 mm (working width) to 5000 mm. It makes sense to match the width of the drum to the width of your printer.
For production speed, the rotary press with a 35 cm drum will keep pace with two or three Mimaki JV33, TS34 or Epson 7000 printers. Traditionally, presses run much faster than the printers; however things are beginning to change with more productive digital printers coming onto market.
When printing cut pieces or panels, a continuous roll of printed transfer paper is fed into the press face up. As the transfer paper passes over the table, the operator lines up individual pre-cut pieces (the front or sleeves of a cycle jersey, for instance) with the printed designs on the paper. The transfer paper, panels/pieces and protection paper are then transported to the heated drum: once the sublimation process is complete and the images fixed, the printed panels or pieces are transported, via a conveyor belt, to the front (or rear) of the machine and dropped into a receptacle for collection. The continuous automated feed allows high volumes of individual panels to be produced consistently, accurately and economically by a single operator and there is no requirement for accurate cutting out after printing. Fashion and sportswear printers favour sport-style presses. You could also use these presses for the all-over printing of made-up T-shirts, but, as stated above, the quality of the result is unlikely to match that achieved on a flatbed press.
Conclusion
Calendar drum pressure , speed and precise temperature control is the key issue of dye sublimation quality, with the good quality heat press for pattern and contour line, the Unikonex vision cutting system will be the best partner for mass production of clothes, sportswear, socks, caps and carpets etc.
Heat press and cutting solution
Unikonex laser cutting system now on working with the worldwide famous sublimation heat press manufacturers like Monti Antonio; Transmatic;Pengda; offer build-to-order options, so heat presses and cutting solution can be tailored to customers’ individual requirements.
For further information and more specific advice on the available heat press and cutting options for wide format dye sublimation printing, please contact Unikoenx.