Whether you’re an experienced importer or just beginning to explore the industry, it is crucial to understand the production process of DTF PET film and the overall DTF printing technology.
Before the emergence of DTF transfer printing, the leading methods in the garment printing industry included heat transfer vinyl, screen printing, print & cut vinyl, and plastisol printing. However, these traditional processes shared a common disadvantage: high labor costs and low production efficiency.
Since its introduction in 2020, DTF transfer printing has rapidly gained global market traction due to its unique advantages. This technology offers an opportunity for businesses in the garment printing sector to diversify and increase efficiency. In fact, investing in DTF printing could be the next significant shift for your company.
As demand for DTF grows, many suppliers have entered the market. When importing DTF products, it is essential to carefully select the right supplier and product. One of the key components you must thoroughly understand is DTF film.
1. What is DTF Transfer Printing?
DTF (Direct to Film) transfer printing is a method that allows designs to be printed on a specialized PET film, coated with a unique adhesive powder, and transferred onto fabric using a heat press.
One of the main advantages of DTF printing is its ability to work on a wide range of materials, including cotton, polyester, and blends—unlike traditional DTG (Direct to Garment) printing, which is typically limited to cotton.
The process involves several steps:
- Design printing: The design is printed directly onto the PET film using water-based inks.
- Powder application: Adhesive powder is applied to the printed film.
- Heat transfer: The film is heat pressed onto fabric, where the design adheres smoothly.
This method’s flexibility, efficiency, and ability to produce high-quality prints make it a popular choice among garment manufacturers.
2. What is DTF Film and its Structure?
DTF film is the critical medium used in DTF printing. It serves as the carrier for the printed design until it is transferred to the fabric. The structure of DTF film consists of several layers:
- Polyethylene Terephthalate (PET) Film Base: This is the primary material, providing durability and stability during the printing and transfer processes.
- Coating Layer: A special coating on the film enables ink adhesion and smooth transfer of the design.
- Release Layer: The film is coated with a release layer, allowing the design to transfer easily onto the fabric when heat-pressed.
Choosing the right DTF film is crucial because the quality of the coating and the base film significantly affects the print’s durability, washability, and overall appearance.
3. How is DTF Film Produced?
The production of DTF film is a complex and precise process that involves multiple stages of coating, stretching, and drying. One of the most critical aspects of this process is maintaining a dust-free production environment.
A clean environment ensures that the coatings are applied evenly and without any contamination, which is essential for achieving high-quality, bubble-free films with uniform light transmission and no noise spots.
Key Factors in Coating Machine Performance:
- Oven Length and Temperature Control: The oven’s length and the ability to maintain precise temperature control are essential for producing consistent results. Smaller factories may opt for an oven length of 25 meters, which typically requires an investment of around 500,000 RMB. For larger operations with an oven length of 70 meters or more, the investment can go up to 1,000,000 RMB.
- Coating Speed Control: The speed at which the film moves through the coating machine also affects the overall quality of the film. A slower speed ensures better adhesion of the coating layers but reduces throughput, while higher speeds can compromise the coating quality if not properly managed.
Maintaining a Dust-Free Production Environment:
Ensuring the coating process takes place in a dust-free environment is critical. Any dust or debris can cause imperfections such as bubbles or uneven coating thickness, which negatively impacts the final product’s quality. To maintain a clean production area:
- Dust-Free Workshop: The entire production area should be kept free of dust and other contaminants. This helps in achieving a smooth, uniform coating that is free of defects.
- Staff Protocols: Workers must follow strict protocols, including wearing proper protective clothing and gear, such as gloves, cleanroom suits, and masks, before entering the production area. This helps minimize contamination risks from human contact.
By controlling the cleanliness of the environment, manufacturers can ensure that each layer of the coating is applied with high precision, resulting in even light transmission, smooth coatings, and no noise spots. This is a critical factor in producing premium quality DTF films.
Detailed Production Process:
- Pre-coating with Matte Release Resin: Before applying the ink absorption coating, a layer of matte release resin is applied to the PET film. This step increases the adhesion between the ink absorption layer and the base film, ensuring better performance during the printing process.
- Mesh Selection:
- Micro-gravure Roll: For the first coat, a 140-170 mesh diagonal ceramic roll is used to apply a single layer.
- Anilox Roll: A 250-280 mesh honeycomb-pattern ceramic roll is used to apply two layers in the subsequent coatings.
- Ceramic Scraper: The coatings are evenly applied using a high-quality ceramic scraper.
- Oven Drying Temperature: Once the coatings are applied, the film is passed through an oven for drying. The drying process is carefully controlled using a parabolic temperature setting. One of the temperature zones must be set between 140-150°C, while other zones should not exceed 130°C. The resin unlocks at 128°C, so if the temperature is too low, the resin will not properly adhere to the base film, resulting in weak adhesion. Conversely, if the temperature is too high for too long, the ink absorption capacity may decline.The quality of the oven plays a significant role in determining the final outcome. Manufacturers need to ensure that the oven maintains consistent temperature and airflow to prevent defects such as uneven drying, which can affect the film’s durability and ink absorption properties.
- Machine Speed: For a 28-meter long oven, the optimal coating speed varies:
- Anilox Roll (two-pass coating process): 60-70 meters per minute.
- Micro-gravure Reverse Coating (one-pass process): 40-45 meters per minute.
- Optimal Coating Thickness: The best dry coating weight is between 4-6 grams per square meter. If the coating is below 4 grams per square meter, the ink absorption may drop below the necessary 100% for optimal results.
- Pseudoplasticity in Materials: When materials are at rest, they tend to form a pseudo-thickening state (pseudoplastic behavior), which temporarily increases their viscosity. This phenomenon helps prevent sedimentation of suspended particles in the coating. Once stirred, the material returns to its original liquid state, ensuring consistent quality throughout large-scale production.
- Viscosity Adjustment: Depending on the specific coating process, up to 20% of pure water can be used to adjust the viscosity of the coating material. However, for the highest quality results, using the original undiluted coating solution produces the best quality product.
Final Oven Process and Quality Control:
Once the coating process is complete, the film enters the oven. At this stage, the role of the oven becomes critical. The oven needs to be precisely calibrated to maintain the correct temperature and airflow throughout the drying process.
High-quality ovens ensure that the film dries evenly, preventing issues such as uneven coating, bubbles, or noise spots.
The film’s journey through the oven is the final step before it is ready for slitting and packaging. Proper temperature control and adherence to production protocols guarantee a high-quality end product.
A carefully managed process leads to bubble-free coatings, even transparency, and smooth finishes, which are crucial factors in the DTF film’s overall performance.
4. DTF Film as a Component in the DTF Printing System
If we compare the DTF film to a tire in a vehicle, then the whole DTF printing system can be considered the full “car” that ensures seamless operation. A successful DTF printing business requires not only high-quality film but also reliable equipment and consumables. Key components include:
- DTF Printer: The “engine” of your system, this printer applies the design onto the PET film.
- DTF Ink: This specialized ink adheres to the film and transfers smoothly onto the fabric during the heat press process.
- DTF Powder: The adhesive powder is critical for ensuring the design sticks to the fabric.
- DTF Powder Shaker: This equipment automatically spreads the adhesive powder evenly on the printed design.
When investing in DTF technology, it’s essential to understand how each of these components works together. The quality of each part will ultimately impact your production efficiency and the final product’s quality.
5. Frequently Asked Questions (FAQs)
Q1: Can DTF printing be used on any type of fabric?
Yes, one of the major advantages of DTF printing is its versatility. It can be used on cotton, polyester, cotton-poly blends, and other fabric types, making it highly flexible compared to other printing methods.
Q2: How does DTF compare to DTG printing?
While DTG (Direct to Garment) printing is limited to cotton fabrics, DTF offers broader fabric compatibility, making it a more versatile solution. Additionally, DTF generally requires less maintenance than DTG printers.
Q3: Is the DTF printing process environmentally friendly?
DTF printing uses water-based inks, which are less harmful to the environment than some other printing methods that use solvent-based inks. However, like all industrial processes, it still requires careful management of waste and resources.
Q4: How durable are DTF prints?
When properly done, DTF prints can be highly durable, with excellent washability and long-lasting vibrancy. The quality of the film, ink, and powder all play significant roles in determining the durability.
Q5: What is the cost of setting up a DTF printing system?
The cost varies based on the size and type of equipment. While the upfront investment may seem high, DTF systems offer a high return on investment due to their efficiency and low labor requirements.
Summary
In conclusion, DTF transfer printing is an innovative and efficient solution for the garment printing industry.
Understanding the DTF PET film production process and its components—including film quality, printers, ink, and powder—is key to making informed decisions when investing in this technology. For companies looking to improve production efficiency and expand their offerings, DTF printing presents a valuable opportunity.
