In-mold decoration (IMD) and film insert molding (FIM) have diversified patterns. They are both affordable, and belong to hot stamping. Hot stamping is a method of transferring a coating on a carrier foil film to the surface by heating and pressure. In the 1990s, this technology began to be applied in the decoration of automobile interiors.

In-mold decoration

What is in-mold decoration? After the printed film is formed, it is embedded in the injection mold cavity, and then the mold is closed for injection molding. The injection resin is combined with the ink layer on the back of the film.

Film insert molding

Film insert molding uses method of thermal blister molding or high-pressure molding to stretch the printed film (the thickness is usually 0.5mm) in three times. The film is cut into the inserts according to the product shape. Then we accurately place the insert into the injection mold cavity for injection molding.

The film for FIM is ABS film or ABS+PMMA. The thickness is generally 0.5mm. PMMA accounts for about 25%, that is 0.125mm. As we all know, PMMA has better scratch resistance than that of ABS, there are currently more ABS+PMMA composite films in automotive interiors.

The common production process of FIM is film heating, high-pressure blow molding (or blister molding), die cutting, placing the formed film into mold cavity, mold closing, injection molding, and mold opening to complete the production.

The overall production process of FIM is basically the same as that of in-molding label, except that the degree of stretching is higher, and the diaphragm material selected is different. This technology is widely applied in the automotive industry.

Difference between IMD and FIM

From a technical point of view, the molding process of IMD is simpler than that of FIM. It's one-time molding, while FIM adds the process of attaching ABS to the film and the precise edge cutting of the film after that. The cost of precision-cut molds is generally higher than IMD.

Although FIM is more complex, it has advantages in the complex and changing interior that IMD cannot do. IMD will cause large stretching deformation of graphics on complex 3D curved surfaces, while FIM can effectively minimize the amount of deformation.

Another obvious advantage of FIM is that it can form a very strong 3D texture on the film surface, both tactile and visual, while the tactile sensation of IMD is weak.

Application

In terms of the style of surface texture, there are imitation metal brushed style, geometric technology texture style and imitation peach wood texture style.

Conclusion

The surface decoration effect of IMD and FIM has always been in the direction of the real texture. For example, more and more metallic inks are added to the films to give the surface more metallic luster. While the imitation wood grain texture begins on its surface to imitate the rough feel. For automobile manufacturers with increasingly strict cost control, IMD and FIM are good solutions for interior decoration of economical models.