IMD (In-Mold Decoration) Technology Screen Printing Inks:
What is IMD labels in Home Appliances?
IMD technology, which includes techniques like ABS injection molding, is applied to various products, with differences in material selection and technical processes. For instance, common printing substrates typically include PET, PC, PC/acrylic composite sheets, and PP, while the ink models can be halogen and halogen-free, weather-resistant and non-weather-resistant, as well as high stretch and low stretch options. Injection molding materials often consist of ABS, PC, ABS & PC, TPU, PS, acrylic, and other choices. Injection molding processes can involve front injection molding, reverse injection molding, or simultaneous front and back injection molding.
Today, I want to discuss the common challenges and solutions during the manufacturing process of IMD products that utilize PET sheets as the printing substrate and ABS as the injection molding material. These materials are commonly used in the home appliance panel industry.
Before diving into this topic, let's first understand the two main components of IMD ink and PET sheets, as most common issues encountered in the manufacturing of IMD products are closely tied to these elements.
IMD Process (In-Mold Decoration)
The IMD process involves using printed films integrated into the mold. After injection molding, this process achieves a decorative printing texture that combines product design, mold technology, and traditional post-processing techniques. The main materials involved include sheets, resins, and screen printing inks. Depending on the process and product structure, IMD can be categorized into three types: In-Mold Label (IML-2D), which is relatively expensive; In-Mold Roller transfer (IMR-2D), widely used in Lokia mobile phones; and In-Mold Forming (IMF-3D).
IML Process (In-Mold Labeling)
The material injection molding process is as follows:
1) Cutting material: Cut the rolled film into square blocks of the designed size for printing and forming processes.
2) Flat printing: Create film nets according to the required icons and texts, then print them onto the cut film square blocks.
3) Ink drying and fixing: The printed film squares are placed in a high-temperature oven to dry, ensuring that the IML ink is fixed.
4) Paste protective film: To protect the printed film surface during the punching of positioning holes, a single or double layer protective film may be applied.
5) Punching positioning hole: Accurate hot forming of positioning holes is essential. Sometimes, the positioning holes are punched in advance during the cutting process.
6) Thermoforming (high pressure or copper mold): After heating the printed film, a high-pressure machine or copper mold is used to form it in a preheated state.
7) Cut the outer shape: Remove the waste material from the formed solid film.
8) Material injection molding: The film, which has the same three-dimensional shape as the front mold, is placed on the front mold post-molding, and the IML product is injected. The application field of IML is expanding, currently utilized in mobile phones and the white goods industry, with future developments aimed at anti-counterfeiting marks. Additionally, its products in the automotive industry offer excellent sunscreen performance and can be used for labels on vehicles with a hardness rating of up to 2H~3H, as well as mobile phone lenses and other components with a lifespan exceeding 5 million cycles, including rice cookers.
