By Cassandra Balentine
Dye-sublimation (dye-sub) is a popular method for printing on textiles as well as some hard surfaces. Print providers have options for dye-sub, including direct and transfer. Each process relies on the presence of heat to infuse the ink onto a fabric or rigid surface.
With a transfer method, images are printed to transfer paper and then sublimated when heat releases ink from the paper into the fabric or medium. This is done via a heat press or transfer device. Direct dye-sub printing involves printing inks directly to the fabric, eliminating the need for transfer paper, but requiring pretreated fabrics and a heat press or calendar to set the inks.
Heat presses/transfer devices are integral to the dye-sub transfer process and should be considered as part of any purchasing decision when entering dye-sub printing.
Several types of heat transfer devices are on the market, including roll, swing away, and clamshell. Each have pros and cons that should be thoroughly considered prior to investing in the dye-sub process.
Above: BPGraphics of Phoenix, AZ finds it faster and more economical to print on transfer paper and then change out the fabric being transferred to on the heat press. It uses a Monti Antonio heat calendar.
As stated above, many types of heat presses are available, including rotary or roll, swing away, and clamshell.
On the smaller end of the spectrum, desktop heat presses are used for sublimating smaller substrates, both textile and non-textile. “Larger substrates can only be sublimated on a calender press or a similar-size or larger heat press,” offers Henri Coeme, global sales manager, HIX Corporation.
For larger format presses, Coeme says even heat and pressure is critical, but so is moisture management. Moisture originating from the paper, the substrate, and the pad can quickly ruin any printed image if not properly absorbed by protective paper and tissue.
For dye-sub transfer printing, Eric Wang, director/manager, Eastsign International Ltd., points out that different heat transfer methods have a greater impact on the speed and efficiency of transfer.
Roll/rotary presses or calenders are used for roll-to-roll or piece production and are generally found in high-volume, industrial applications.
“The rotary transfer machine is the fastest. It greatly reduces the operating time during production and increases the production speed,” explains Wang.
John Selfhout, commercial director, Klieverik, says this kind of heat press offers high productivity and reproducibility.
For rotary transfer machines, Wang believes the main focus should be the temperature of the oil drum, the tension of the blanket covering the oil drum, and whether the transfer paper and cloth are neatly fed. “This will determine whether the color of the finished product has chromatic aberrations and wrinkles.”
Roll presses are limited to continuous roll fabric, so rigid substrates are not compatible and piece goods not possible on many models, says Aaron Knight, VP, Geo Knight & Co., Inc.
Swing away heat transfer machines are often found in high-volume, commercial environments and use a more sophisticated construction enabling the heat platen to swing to the left or right, shares Chase Pender, business development manager, Supply 55, Inc. “This helps with positioning items across the heat platen.”
Sizing is also a consideration for swing away heat transfer devices, many are limited to 20×25 inches, according to Knight.
For small-size sublimation, Coeme says swing away presses are mostly recommended since even pressure is more important than speed.
Clamshell presses are known to offer a cost-effective solution with a simple design. According to Pender these are the most common type of entry-level heat presses.
Knight adds that clamshell presses are ideal for light-use, non-production runs and single-layer fabrics.
Coeme says clamshell machines should not be overlooked; especially if these are built with a mobile lower platen that can set itself to various thicknesses of the substrate as the press closes.
The main drawbacks according to Pender for clamshell presses are the possibility of touching the heat platen with your hand and pressure is not perfectly even because the back of the press is always smaller than at the front, which can lead to issues.
In addition to commonly referenced heat transfer devices, including rotary, swing away, and clamshell, slide shuttle options are available.
Large format slide shuttle presses are well suited for any and all applications, according to Knight. These solutions are offered in a range of sizes, including 26×32, 32×42, 44×64, 54×84, 54×103 inches with single table and dual loading shuttle table and bottom heat options. “These shuttle/drawer style large format presses are the most popular large format machinery solution in the industry,” he offers.
For dye-sub transfer printing, transfer paper is an important consideration for the process. However, it isn’t typically a limiting factor in terms of the heating device.
“The press is more suited and geared towards certain substrates, thicknesses, and types of materials being printed, not the transfer paper itself,” explains Knight.
Selfhout says for roll presses, any brand of paper will work. “However, for best constancy and color yield, A-brands will be more cost effective.”
Applications Per Press
There are limitations on what applications can be accomplished with particular heat transfer devices, which is often due to sizing.
Clamshell heat presses are ideal for screenprinted-style shirts, environments with limited space, as well as direct to garment and pre-made transfer solutions.
With limitations regarding pressure, Pender says clamshell presses are a good entry-level solution for heat vinyl transfer that is cut with a vinyl cutter, desktop dye-sub transfers, and most other types of transfers that require low to medium pressure. “The lower price point makes them a good choice for occasional use,” he adds.
Swing away presses allow for sublimation onto a variety of non-fabric substrates and very thick materials, suggests Knight.
Pender feels that swing away presses are a solid choice for everyday use, especially for dye-sub transfers as the pressure is more evenly distributed across the whole platen.
Roll/rotary heat transfer presses are well suited for industrial dye-sub solutions. Selfhout points out that these machines are good for garment, sportsware, home textiles, and signage.
Rotary transfer machine equipment should be selected based primarily on the size of the oil drum, recommends Wang. These are typically 420, 600, 800, 1,000 millimeters (mm). He says the size of the oil drum will affect the transfer speed. “Customers in the apparel industry with a small output generally choose 420 mm oil drums, those in the clothing industry with a large output generally choose 600 to 800 mm oil drums, and large textile industry customers generally choose oil drums above 1,000 mm,” he offers.
For a clamshell heat press, users can expect to pay anywhere from $650 to $3,000; manual swing away presses range from $300 to under $1,000; and automatic swing away presses come in around $4,500.
Larger format shuttle/drawer transfer devices run between $12,000 and $52,000, with most popular sizes falling in the $12,000 to $19,000 range.
For roll presses, Selfhout says users can expect to pay upwards of $30,000.
Pricing for rotary transfer presses vary based on the size of the oil drum. For the 420 mm size, Wang estimates $20,000 to $30,000; 600 mm run about $30,000 to $40,000, 800 mm come in at approximately $36,000 to $46,000; and 10,000 mm drums are above $50,000. For smaller proofing equipment the price is about $7,000 to $10,000.
Production Vs. Prototyping
The requirements for dye-sub of short runs or one-offs vary greatly when compared to production- or industrial-level work.
Clamshell devices are best for lighter use environments, or situations where portability is a benefit.
“Due to the construction, the positioning of garments is more time consuming on a clamshell press and not as efficient as on a swing away heat press,” shares Pender. “A clamshell press is therefore fine for regular use and medium production amounts or of course prototypes or single motive garments.”
For high-volume, all-day use, Pender recommends a swing away press. “With smart solutions like the slide option, the efficiency can be improved for swing away presses as garments can be positioned during the pressing resulting in less idle time,” he offers.
Another important factor is whether the press is manual or automatic. “Presses with manual openings tend to require more manual effort and reduce productivity compared to auto-open versions,” comments Pender.
He points out that swing away presses are more expensive than clamshell presses and offer more efficient use and easier positioning of garments. “For very large volumes or precise high pressure, pneumatic versions of swing away presses are usually superior over manual versions but carry a significantly higher price tag.”
For bulk, uncut continuous fabric, roll or rotary presses are ideal. These are meant for production volumes.
Selfhout says roll heat transfer devices are industrial equipment designed for reproducibility; the possibility to sell the same article that is color consistent with the first one/sample.
Heat it Up
When it comes to digital dye-sub printing, heating is an essential element. Luckily there are a variety of heating devices to choose from, including clamshell, swing away, slide shuttle, and roll/rotary. Volumes, mediums, and applications help narrow down the options.
Aug2021, Industrial Print Magazine