Introduction and Overview

CMF refers to the Color, Material, and Finish of a product. As a fundamental logic in product design, it delivers unique visual and tactile experiences to products through the coordination of color matching, material selection, and surface processing technologies.

Among these, IMD (In-Mold Decoration) has emerged as one of the most representative surface treatment technologies in the CMF design system, and is widely applied in various fields such as automotive interiors, home appliances, 3C digital products, and medical devices.

From a CMF perspective, this paper combines industry references and process experience to provide an in-depth analysis of the classification, production workflow, and practical applications of IMD technology.

IMD (In-Mold Decoration) is an integrated process in which pre-printed decorative films of PC or PET are directly embedded onto the surface of plastic parts during the injection molding stage. Simply put, it "dresses the product in a custom coat" simultaneously with the molding of the plastic component. This integrates patterns, textures, colors, and structural parts in a single step, realizing the unified forming of both decoration and structure.

In terms of performance, the integrated forming of the decorative layer and the substrate in the IMD process delivers excellent wear resistance, scratch resistance, and chemical corrosion resistance. It meets the requirements of high-frequency contact applications and effectively extends product service life. For appearance and texture, IMD can achieve diverse surface effects such as high-gloss, matte, wood grain, and metallic textures, significantly enhancing product grade and visual experience.

This process features high production efficiency: single-step forming greatly shortens the production cycle, making it suitable for stable mass production. It also has good compatibility with various plastic substrates including ABS, PC, and PMMA. Environmentally, IMD reduces solvent emissions and waste generation compared with traditional processes, and some films are recyclable, aligning with the concept of green manufacturing. For long-term benefits, it lowers product repair and scrap rates, optimizing costs across the entire life cycle.

• Ink Types

  UV Ink: Fast curing, vibrant colors, and excellent weather resistance.

  Solvent-Based Ink: Lower cost but may emit harmful substances; color stability and high-temperature resistance require evaluation.

  Water-Based Ink: Eco-friendly but slow drying; a trade-off between color reproduction and process efficiency is needed.

• Key Ink Property Parameters

  High-Temperature Resistance: IMD injection molding temperatures typically reach 150–300 °C, so the ink must withstand these temperatures without discoloration or decomposition.

  Transparency and Hiding Power: Choose transparent ink (for gradient effects) or opaque ink (for solid colors). Color card testing is required to avoid show-through or color deviation.

• Color Management

  Reference Standard Color Charts: Such as Pantone and RAL color charts, with clearly specified color numbers.

  Digital Color Tools: Use a spectrophotometer to measure the ink's Lab values (CIE Lab* color space) to ensure color difference is below common industry standards.

  Environmental Control: Conduct color evaluation under standard light sources to avoid interference from ambient light.

• Planar Texture: Uniform color, gradient patterns or geometric graphics. Realized via screen printing, commonly used in minimalist-style products for a clean visual experience.

• Simulated Natural Texture: Wood grain, stone grain, leather grain, etc. Imitates the texture of real materials through high-precision printing or digital printing, often applied in high-end home appliances or automotive interiors to create a luxurious feel.

• Special Effect Texture: Such as metallic finish, pearlescent effect, holographic texture, achieved with special inks.

• 3D Stereoscopic Texture: Such as embossed/debossed patterns and depth effects, enhancing three-dimensionality and interactive experience.

• Smooth Texture: Flat and delicate surface with comfortable touch. Realized by using high-gloss films or mold polishing, commonly seen in screen bezels of consumer electronics.

• Frosted Texture: Slightly rough surface that reduces glare and improves grip. Achieved through fine sandblasting of the mold or frosted coating on the film, often used for mobile phone casings or tool handles.

• Embossed/Debossed Texture: Such as dots, lines or custom patterns, providing clear tactile feedback. Created by mold engraving and transferred to the product surface during injection molding.

• Composite Texture: Combines visual and tactile elements, such as fabric-like texture with both visual patterns and soft touch. Realized via special film materials (e.g., fabric-like films) and mold design, used for household products or wearable devices.

• Types: High-Gloss, Semi-Gloss, and Matte.

• Implementation: Mold surface treatment, film pre-treatment.

• Types: Leather grain, wood grain, geometric patterns, frosted grain, etc., providing tactile and visual layering.

• Implementation: Mold engraving, textured film.

• Types: UV scratch-resistant coating, anti-fingerprint coating, hard coating, anti-glare coating.

• Implementation: Film-integrated coating, post-finish spraying.

• Types: Electroplating effect, Physical Vapor Deposition (PVD), metallic effect printing.

• Implementation: Vacuum metallized film, metallic ink printing.

• Types: 3D stereoscopic effect, transparent/translucent effect, fluorescent effect, color-changing effect.

• Implementation: Multi-layer film technology, optical coating.

• Types: Screen printing, digital printing, pad printing, for adding logos, patterns or gradient colors.

• Implementation: Pre-printing on the film, followed by integral molding with the product via the IMD process.