Direct-to-Film (DTF) Printing Technology
What is DTF Printing?
The main gist behind DTF printing is pretty simple – print on a film, and transfer it onto the fabric of choice with a heat press. This new technology has been gaining traction overseas due to its flexibility to print on almost every possible fabric or leather. It makes no difference be it cotton, silk, polyester, synthetic fabrics, genuine leather, or synthetic leather – the DTF printing process can be applied to all of them.
Pre-Requisites For DTF Printing
Shifting over to the use of DTF technology is very clear cut and straightforward. It doesn’t matter whether you are currently engaged in a screen-printing t-shirt process, DTG printing process, or even as a new business, DTF printing technology does not require a heavy initial investment.
Basic materials to run a DTF printing process includes the following:
Direct to Film Printer
You may either opt to invest in the following:
- Roll-to-Roll (RTR) printer with a 60 cm printing width
- Epson F2130 Direct to Garment (DTG) printer
The RTR printer will be able to provide you with a continuous printing ability which caters for large volume printings whereas the Epson F2130 provides you with the flexibility to print with 2 technologies – DTG and DTF.
The reason as to why the Epson DTG machine is able to utilise DTF’s printing technology is due to its ability to worth with white ink. The direct to garment printer’s ink tank has a special circulation function just for its white colour. A layer of white ink is the magic behind DTF’s ability to work on DTF Film.
** Do take note that there are cheap after-market DTF printers that utilises the Epson L800, L805, L1800, etc. There are several reasons why it is not advisable to buy these printers.
- These printers are meant to be desktop printers to print on normal copier printing papers.
- The conversion of the mentioned printers includes the removal of several pinch rollers so as to prevent rolling track marks on the final print. This will compromise the integrity of your final print as your feeding film might lose traction resulting in the skidding and jamming of your film.
- These desktop printers also do not have a special channel for white ink. White ink is channelled through the Lc and Lm tank instead.
- These after-market printers do not have white ink circulation function. As a result, when you replace the tanks with white ink, it will damage your printheads in the near future as white ink particles tend to sink
- and solidify on printheads when circulation does not happen.
In the DTF printing process PET films are used as the primary substrate – We shall refer these films as DTF Transfer Films, which is different as compared to those use in screen printing. With a thickness of about 0.75mm, DTF Transfer Films have better transfer characteristics as compared to other kinds of film. The films are available in the form of cut sheets to be used with the Epson F2130 DTG, or rolls to be used with the roll-to-roll printer. In addition, the films can be classified based on their “peeling” type – Hot peel or cold peel.
The software used is also crucial in the process of DTF printing. Print characteristics, ink colour performance, and final print performance on the fabric/t-shirt after the transfers are greatly influenced by the software used in the printing process. That being said, a specialised RIP software is required such that it can handle CMYK and White colours. Colour profiling, ink levels, drop sizes and other factors contributing to an optimized print result are all governed by the DTF RIP Software.
The DTF printing process requires the use of an adhesive powder. This substance will melt using high heat and will act as glue that binds the coloured pigments in the prints onto the fabric/t-shirt.
DTF Printing Inks
DTF printing inks are a specially designed water-based pigment inks that are available in Cyan, Magenta, Yellow, Black, and White Colours. A layer of White ink is a special component that is required between the adhesive powder and coloured inks.
Automatic Powder Distributor / Curing Machine
The powder distributor is used in the roll-to-roll DTF solution. The application will evenly distribute and remove excess powder before the film is transferred onto the curing machine. The curing machine is an industrial conveyor belt oven that cures the adhesive powder onto the film.
In the event that the printer used is an Epson F2130, application of the adhesive powder can be done manually by using a tray and sprinkling in the middle of the print before using a heat press or a small curing oven to cure the adhesive powder onto the film.
A heat-press machine is mainly used to transfer the printed image onto the film onto the fabric or t-shirt. When using a roll-to-roll printer, it is recommended that you use a more efficient automatic heat-press machine that that has 2 press stations.
Basic Fabrication Process
Step 1 – Print on Film
Load the DTF Transfer film onto the printer. Set your prints to “mirror image”. Be sure to use proper profiling and resolution from the RIP software. Select white as an under base and you may begin printing. Print layer 1 as CMYK and layer 2 as white.
Step 2 & 3 – Powdering and Curing
When using the powdering cum curing machine, the film will be fed through the machine where powdering and curing is done automatically.
When using an Epson F2130, powdering and curing is done manually. Sprinkle the adhesive powder evenly on the film when the print is wet and the excess powder needs to be removed carefully. It is important to ensure that the powder is evenly spread all over the printed surface on the film. One common way to ensure an even distribution is to hold the film in a landscape orientation and pour the powder in the middle of the film at approximately 1 inch thick in the centre from top to bottom. Pick up the film altogether in a ‘U’ shape and rock the film from left to right spreading the adhesive powder slowly and evenly across the surface of the film.
Once the powder is evenly spread out, place the film in a small oven or use the heat press to cure the adhesive powder by hovering it around 5mm gap between the film and heat plate. For the best result, it is highly recommended to follow the manufacturer specification to cure the powder. Depending on the powder and equipment, the heating is generally done in approximately 1 minute at temperatures between 160 – 170 Degree Celsius.
Step 4 – Pre-pressing (Optional)
This optional step involves pre-pressing of the fabric prior to the transfer of the image on the film. The fabric is kept in the heat press and pressurized under heat for approximately 5 -10 seconds to flatten the fabric. The pre-pressing will aid in the proper transfer of the image from the film onto the fabric.
Step 5 – Transfer
This step is the most crucial in the DTF printing process. The transfer film with the image and the cured powder is placed on the fabric in the heat press. The transferring is done at temperatures between 160 – 180 Degree Celsius for approximately 15 seconds. The film is now firmly attached to the fabric.
Step 6 – Peeling
It is important that the fabric and the now attached film cools before peeling. As a result, the printed design will bind into the fabric/t-shirt, allowing you to peel off the film easily.
Step 7 – Post Pressing (Optional)
Post pressing is optional, but recommended. It enhances parameters such as washing and rub fastness. Post-pressing can be done in approximately 5 – 10 seconds.
Pros & Cons To DTF Printing
Similar to all forms of printing, there are advantages and disadvantages which will be addressed in this segment.
Pros1. This process works with almost all types of fabrics.
2. When printing on coloured t-shirts, pre-treatment is not necessary.
3. Colours on the end product are sharper and more vibrant.
4. DTF prints have good stretch tolerance.
5. Fabrics with DTF prints exhibit good wash characteristics.
6. The underside of the fabric would have little hand feel.
7. DTF printing process is faster and less tedious as compared to DTG printing process.
1. The end result of the print on fabric has a slight rubberish feel as compared to prints done using the DTG process on a white t-shirt.
Overall, one could say that the DTF printing process practically lifts all restrictions that are common in all other textile printing processes especially when it comes to choosing the type of fabric the design will be printed on.
In addition, since pre-treatment is no longer required in the DTF printing process, the overall cost of printing will be drastically reduced, hence offering users a higher profit margin.
The addition of DTF printing technology is expected to drive the global textile printing machine market to $13.98 billion by 2025 (ICON Group, 2019) as more and more fabrics printed using DTF technology will come into play.
In conclusion, the DTF printing process is an effective way to produce fabric economically.