Heat Press Tech
Heat Transfer Introduction
In this section, we will attempt to help you better understand and operate your HIX Heat Transfer equipment. We have assembled many of the questions we have received with the intention of helping to guide, troubleshoot, and solve your problems.
There are three things that affect the success of heat-applied transfers. Every heat press must be able to control TIME, TEMPERATURE, and PRESSURE.
• Time – Time can be controlled by a simple bell or egg timer, or an audible beeper or alarm timers. Time can also be regulated by an automatic opening feature, where the press opens automatically at the end of a preset time, such as our N-880, N-680, S-450, S-650 models.
• Temperature – Reliable temperature is a key issue in most transfer application failures. When a 350° readout is really only 320°F, a transfer requiring 350° for application won’t work. A warped heat casting (even slightly) can lead to unevenly applied heat and the transfer won’t adhere to the substrate. Some manufacturers (not Hix) produce heat presses that use two elements in their heat platen. If the tolerances are ±3%; at 400°F – 3% = 12° and 400° + 3% = 12°, that is a total of 24°. Their heat platen temperatures can vary side to side and cause transfer failure. If you have a 5 second transfer, the press works, but heat recovery time is usually 15 seconds. If you are cycling faster, the press will not recover to full heat and you will begin to have transfer failure. With the N-880 model, we do offer a hotter heat head with more amperage in its 16”x20” size. This is a special order item.
• Pressure – Even and consistent pressure for the entire time is critical for good transfer application. Poor alignment of the heat head with lower platen, warped castings, and pad buildup or void (air pocket or trouble in pad) all contribute to pressure failures.
Note: always consult the transfer manufacturer for the proper time, temperature and condition of peel.
FLOCK: A versatile transfer, manufactured by electrostatically charging and aligning short, synthetic fibers. It offers a three dimensional quality that is durable and inexpensive. Can be permanently applied to most fabrics, with the exception of 100% nylon. Great for unique fabrics such as corduroy and terry cloth. Flock transfers generally are cold peel.
FOILS: A metallic film that is either printed with an adhesive or is sometimes used in a two-part type of transfer, giving a shiny, glittering, metallic sheen look to the substrate. Foils come in a variety of colors and are usually the type of transfers one would find in the boutiques, because they give the appearance of flash and definitely draw attention to themselves (especially on dark or black fabrics).
HAND: The degree to which a print or a transfer is discernible to the touch. A soft hand print/transfer is not able to be detected from the feel of the unprinted garment.
HOT PEEL: A transfer with some of the look and feel of a hot split but can be used on dark fabrics. It must be peeled immediately.
HOT SPLIT: A transfer which is peeled immediately upon the completion of the transfer dwell time. These transfers are printed on a bond-like paper (with low release capacity). The hot split ink allows for the ink to literally separate from the paper while still hot. When peeled, the ink splits, and it leaves a small amount of ink on the paper while the balance transfers on the garment, giving the look and feel of a soft hand direct print vs. that of the ordinary cold peel transfer.
PLATEN OR CASTING: The working surface – the upper or lower castings of the heat transfer machine. For example, the 15” manual press has a 15” x 15” platen size. Heat castings are aluminum with the heat source cast in or fixed into the casting. Lower castings are generally padded with a compressible heat-resistant foam pad glued to a steel or aluminum plate or casting.
PUFF: A hot split specialty transfer that has a chemical blowing agent that usually reacts (at 375° – 400°) with the ink and “puffs up,” giving an added dimension to the transfer. Puff inks are used in transfers either singularly or in combination with hot split inks to give a special highlighted effect to the transfer.
Note: If the puff (chemical blowing agent) does not occur, check temperature and pressure. Always consult the transfer manufacturer for the proper time, temperature, and condition of peel.
SUBSTRATES: The item being printed on a T-shirt, mouse pad, tile or a coffee mug that is to receive the transfer.
DIGITAL HEAT TRANSFER: A transfer that is computer-generated and printed through a digital device such as an ink jet, laser printer, or color laser copier. By using the digital four-color process CMYK, Cyan (blue), Magenta (red) Yellow, and Black (or 3-color without the black), you could create an infinite array of colors on one image.
COMPUTER/CLC HEAT TRANSFER PAPER: Specialty coated transfer papers used to apply computer-generated graphics onto substrates. The coating on the paper accepts and holds the inks or toners from various computer printers or color laser copiers. The paper is then applied to a wide variety of substrates using a heat press. Heat and pressure are applied to the transfer while the paper’s coating carries the inks or toners and embeds them into the surface of the substrate. The following are the different digital types of transfers and transfer papers that are available. For applications, see “substrates.”
INK JET: Transfers can be made on a standard ink jet printer using coated ink jet transfer paper. Similar to the CLC papers, ink jet transfer papers have a coating that melts and fuses the ink to the substrate. The beauty of printing digital ink jet transfers is that they are inexpensive to make while the print holds up well on garments after the laundering process.
CLC/ CLP DIGITAL TRANSFERS: The term CLC is an acronym for Color Laser Copier. These CLC transfers are printed on specially coated transfer paper. The term CLP stands for Color Laser Printer. Digital CLP transfers are printed on a color laser printer with standard toners onto a coated transfer paper. The transfer paper is coated with a heat transferable polyester coating that bonds the laser toner to the garments by trapping the ink between the polyester heat-seal coating and the garment. For proper application of the finished transfer, a commercial heat transfer machine is needed with settings to control time, temperature, and pressure. Although CLC and CLP transfers are similar, the same cannot be said about the paper stock used. Many papers used with CLCs will not work for CLPs. The fusing process is hotter in CLCs, causing the toner to melt the coated paper in the fuser section of the copy machine. Some companies now offer a paper that will work for both applications, but be sure to ask! Laser papers are designed to accept toners/dyes from color laser printers. These papers are specially designed for the high temperatures in the fusing section of laser printers. Laser papers are durable and washable.
OPAQUE: Opaque papers are designed to allow a transfer to be printed on dark colored substrates. There are one-step opaque papers and two-step papers. Two-step papers first provide a white backing to be printed on in a second step, so that full color range is visible on dark garments. One-step papers incorporate opacity with the inks/toners used. Opaque is recommended for cottons only.
SUBLIMATION: Sublimation is defined as “to cause (a solid or gas) to change state without becoming liquid.” The sublimation process is used to imprint objects by applying dyes that turn from a solid to a gas when heated. In order for the process to succeed, the substrate to be printed needs to possess a high level of polyester, or have a polyester surface applied to accept the sublimation ink when heated. To transfer the sublimated image from the paper carrier to the substrate, the paper is placed in contact with the substrate and heated to the appropriate temperature in the range of 385 to 425, depending on your ink manufacturer’s guidelines. When heated properly, the molecules of the polyester coating (or substrate) open up and accept the sublimation gas into the open pores, trapping the ink in the polyester molecules. When the polyester coating cools, it encapsulates the ink. Sublimation digital transfers are typically printed on an ink jet printer using special sublimation ink cartridges and transfer paper made specifically for sublimation. Full color sublimation transfers allow for printing on polyester clothing and plastics as well as specially coated woods, metals, glass and ceramics. They provide bright, rich, full color and sharp images.
SUBSTRATES: For digital transfers, substrates are broken down into two categories.
Soft or Flexible Substrates: T-shirts, sweat shirts, hats, aprons, tote bags, mouse pads, place mats, fabric coasters, fabric notebooks, photo albums, puzzles, beverage insulators, visors etc. They generally can be decorated using all transfer types (ink jet, laser, resin/thermal, CLC, and sublimation).
Hard or Rigid Substrates: Plaques, coasters, clipboards, dry erase boards, clocks, picture frames, license plates, name badges, luggage tags, magnetic material ceramic mugs, tiles, metal plaques, glass plaques, etc, can all be decorated with sublimation and some products with CLC transfers. However, CLC transfers on coated tiles and mugs must be reflowed with heat, such as a mug glazer in order to create a more permanent adhesion with the substrate.
SUBLIMATION COATINGS: The only limiting use for sublimation is that the substrate needs to be polyester or polyester coated, hard or soft. Hard polyester coatings are more durable and retain their crisp image over a longer period of time. Soft coatings are less so, but are easier to print. The harder the coating, the more precise the time, temperature, and pressure parameters need to be controlled to provide the best result.