In-Mold Decoration (IMD) is a surface decoration process in which pre-printed and pre-formed films are placed into an injection mold. Through the pressure and temperature of the molten plastic, the film is integrally formed with the plastic part. It realizes integrated molding of texture, color, and functional coating, with stable appearance, wear resistance, high yield, and suitability for mass automated production. It is widely used in high-end appearance parts such as automotive interiors, home appliance panels, and 3C electronic housings.

Pre-Production Preparation

Material VerificationCheck that the IMD film material, thickness, texture, and printing surface meet drawing requirements. Ensure the film is free of scratches, wrinkles, ink misalignment, or delamination. Verify the injection material grade and drying conditions to ensure full drying, preventing bubbles or silver streaks caused by moisture.

Mold InspectionClean the mold cavity, locating pins, and cavity surface to remove oil, iron chips, and glue residue. Check the precision of the mold positioning structure to ensure the film stays in place without shifting or wrinkling. Confirm smooth cooling circuits and stable temperature control.

Equipment and Tooling SetupAdjust clamping force, injection stroke, and temperature control systems. Prepare film positioning fixtures, vacuum suction devices, and handling tools to ensure accurate film loading. Check robot paths to avoid interference.

Core Process Parameter Settings

Temperature ControlBarrel temperature is slightly lower than conventional injection to avoid damaging the film and ink. Nozzle temperature is reduced to prevent burning the film edge. Mold temperature is controlled to ensure good bonding without film shrinkage.

Pressure and Speed ControlInjection pressure is moderate to avoid shifting or wrinkling the film. Injection speed follows a slow–fast–slow profile to ensure smooth filling. Back pressure is kept low to reduce shear heat.

Time and Position ControlInjection time is set for stable filling. Holding pressure and time are not excessively high to prevent film deformation. Sufficient cooling time ensures stable dimension before ejection.

Film Loading and Positioning

Place the film with the printed side facing the cavity, secured by locating pins or vacuum.

Inspect for flatness, no lifting, shifting, or wrinkling before closing the mold.

Avoid direct contact with the printing surface to prevent fingerprints or contamination.

Injection Molding Operation

Use low parameters for initial trial molds; optimize settings before mass production.

Monitor appearance for bubbles, film shift, deformation, or weld lines.

Control opening and ejection speed to avoid damaging the film.

Common Defects and Solutions

Film shift: Improve positioning, reduce initial injection speed, adjust gate location.Bubbles / Delamination: Increase mold temperature, extend holding time, lower barrel temperature.Wrinkling: Optimize film placement, stabilize mold temperature, reduce local pressure.Ink damage: Lower temperature, shorten high-temperature contact time, use heat-resistant ink.

Quality Inspection

Appearance: No scratches, bubbles, wrinkles, color deviation, or unclear texture.Performance: Strong film adhesion, no peeling, passes abrasion and alcohol tests.Dimension: Conforms to drawings, no warpage or deformation.

Safety and Production Notes

Do not place hands inside the mold; use robots or dedicated tools.

Regularly clean the mold to avoid contamination.

Store films in a dry, dust-free, dark environment.

Conduct regular first-off and in-process inspections.