Custom Plastic Injection Molding Factory

Custom Injection Molding | Plastic Mold Manufacturer | Precision Machining Company

IMD&IML Injection Molding2024-11-23T12:20:25+00:00

IMD&IML Injection Molding

KingStar Mold, established in 2005, is a professional custom IMD and IML injection molding factory.

KingStar Mold’s Real Factory Video

We collaborate with SGS and Alibaba to capture authentic photos of our factory. These updates are shared with customers, providing a detailed view of our operations and a deeper understanding of our company.
  • Office
  • Meeting Room
  • Injection Mold Workshop
  • Injection Molding Workshop
  • Quality Check Room
  • Sample Room
  • Assembly Room
  • Warehouse

KingStar Mold’s Quality Certification

Feel free to email us, and we’ll provide you with the original certifications upon request.

  • ISO 9001: Establishes the criteria for a quality management system, essential for injection mold companies to ensure consistent quality.
  • ISO 13485: Defines the requirements for a quality management system specifically for medical devices and related services, ensuring compliance with customer and regulatory needs.
  • ISO 14001: Specifies the standards for an environmental management system, promoting sustainable and certified practices.
  • ISO 45001: Reflects our commitment to maintaining a safe and healthy workplace. This certification ensures peak team performance, resulting in superior product quality and faster production times for our customers.

IMD Injection Molding

IMD injection molding manufacturing and design guide

What is IMD?

IMD (Injection Molding Decoration, In-Mold Decoration)

IMD is an advanced technology where a decorative film is placed inside the injection mold to enhance the plastic surface.

The film typically consists of three layers:

  • Base Material: Usually PET (polyethylene terephthalate).
  • Ink Layer (INK): Provides the desired patterns or colors.
  • Adhesive Material: A specialized adhesive bonds the film to the plastic.

During the injection molding process, the film adheres closely to the plastic surface through the adhesive. The PET layer is coated with a wear-resistant protective film, making it resistant to wear and scratches, with a surface hardness reaching up to 3H. Remarkably, the surface becomes brighter with regular contact.

Commonly used injection molding materials include PC, PMMA, and PBT, ensuring durability and aesthetic appeal.

What types of IMD processes are there?

Now, there are three main types of construction methods:

IMF (Forming)

IMF combines in-mold injection and in-mold lamination to achieve 3D IMD decoration on plastic parts. It is ideal for high-stretch, edge-wrapped, and 3D plastic parts. IMF parts are structured in three layers:

  • The first layer is a plastic sheet (PC, PET, PMMA, etc.).
  • The second layer is ink, protected within the sandwich structure.
  • The third layer is the molded plastic.

This arrangement ensures the ink is protected from scratches and fading. Applications include PC FILM flat printing, 3D, and 2D forming.

IML (Laminate/Label)
In-Mold Labeling keeps the film on the surface, acting as a protective layer. This method is commonly used for plastic containers to enhance durability and appearance.

IMR (Rolling)
In-Mold Rolling involves thermal transfer, where the decorative film transfers the ink onto the product surface and then detaches. The film does not remain on the surface, making this technique suitable for flat products.

The guide of IMD injection mold design and molding process.

a. Sheet Material
  • Fire-Resistant Properties: PVC is self-extinguishing, meaning it stops burning once the fire source is removed. This fire resistance is due to the high chlorine content in PVC, making it safer for various applications.
  • Material Options: The most commonly used sheet material is PET, but PC and PMMA are also available. PET is favored for its superior molding and processing capabilities, surface gloss, and wear resistance, which align with customer requirements. One of the most widely used PET sheet thicknesses is 0.125mm.
  • Ink Requirements: Ink used for printing must meet specific criteria, including:
    • Wear Resistance: To ensure durability during use.
    • High-Temperature Resistance: To withstand the processing environment.
    • Ease of Application: Simplified preparation and suitability for screen printing operations.

b. Pre-Made Sheets (Thermoforming, Cutting, and more)

The Overall Process Workflow for pre-made sheets involves the following steps:

  1. Printing
    • Tools: Film, screen printing machine.
    • Key Points:
      • Selecting appropriate ink for durability and adhesion.
      • Ensuring accurate sheet positioning for precise results.
  2. Apply Protective Film
    • Purpose: To safeguard the sheet and prevent dust contamination.
    • Material: PE film is commonly used.
  3. Shape Punching
    • Tool: Die.
    • Key Points: Accurate sheet positioning to ensure uniform punching.
  4. Apply Protective Film
    • Reapplied to protect the sheet during subsequent processes.
  5. Heat Setting
    • Tool: Heat setting machine.
    • Key Points:
      • Precise temperature control to prevent deformation and minimize scrap rates.
      • Upper and lower molds equipped with heating plates to maintain a consistent temperature.

Detailed Heat Setting Process:

  • The sheet is placed on the heat setting machine.
  • The movable heating plate moves over the sheet to preheat and soften it.
  • Once preheated, the mold closes for heat setting, shaping the sheet into the desired form.

Proper handling of the heat setting process is crucial to achieve high-quality results and avoid unnecessary waste.

c. Fitting Between Sheet and Cavity

  • Sheet Size Principle: The sheet must be slightly smaller than the final part size.
    • Reason: This allows the sheet to fit easily into the mold cavity and ensures full stretching during the molding process. If the sheet is too large, it may cause wrinkles, resulting in defective products.

2. Mold Shrinkage

  • Typical Shrinkage Rates:
    • ABS and PMMA generally shrink by 0.5%.
    • In IMD molds, due to the PET film layer on the product’s surface, shrinkage is reduced.
  • IMD Mold Consideration:
    • Shrinkage for IMD-produced parts is usually 0.3%, as the PET sheet wrapping the plastic substrate during injection molding limits shrinkage. This is lower than the shrinkage for ordinary molds.

3. Sheet Forming Mold Design

  • a. Sheet 3D Model:
    • Use product images in Pro/E or similar 3D software.
    • Offset the product surface inward by the sheet’s thickness to create a 3D model of the sheet.
  • b. Die and Film Creation:
    • Based on the 3D sheet drawing, unfold it to create the necessary tools, such as dies and films, for sheet punching.
  • c. Mold Separation:
    • Separate the mold into parts based on the 3D sheet design.
  • d. Mold Manufacturing:
    • Manufacture the mold components to the specified design.

By adhering to these steps and principles, you can ensure high-quality sheet forming and injection molding for IMD applications.

What are the characteristics of IMD injection molding?

① The product offers exceptional durability and scratch resistance.

② Complex visual designs can be easily achieved with consistent results, something other processes cannot match.

③ It supports a wide range of colors, even in small production runs, including the ability to print over four colors and metallic inks.

④ Design changes can be made without requiring additional molds, leading to substantial cost reductions.

⑤ One-piece molding exclude the need for color separation and disassembly, accelerating the design and development process.

⑥ The product features high color contrast, and the plastic material allows light transmission, making it ideal for screens and light guide columns.

⑦ The product has excellent chemical resistance due to its extremely durable and flexible surface printing. The image is actually printed on the inside of the film.

⑧ Plastics and films can be recycled and reused.

⑨ The product can meet precision requirements and enable efficient mass production through automation.

The top tips for IMD injection molding

Since IMD ink can withstand temperatures between 250-260°C for 3-4 seconds, designing the injection mold requires careful consideration of factors such as injection pressure, injection time, gate size and quantity, and the material’s physical properties. To achieve low injection pressure and short injection times, the following methods can be considered:

① A shorter runner design is preferable, with hot runners being the ideal choice.

② Consider increasing the gate area or using multi-point gates.

③ Opt for plastics that have better flow and inject them at a lower temperature.

④ To prevent ink from being flushed out, add it at the gate.

⑤ Ensure that the IMD injection mold cavity and mold shape align properly.

⑥ Avoid selecting the highest stretch points for the injection material, usually at the four corners, as these areas are thinner, expand and contract more, and are prone to wrinkles.

⑦ Since IMD injection conditions tend to be consistent, using an injection molding machine with superior control is recommended. Additionally, the plastic’s physical properties should be uniform.

⑧ Since the FILM expands and contracts with temperature changes, the mold temperature should not be too high during molding. Using a mold temperature machine is a good approach.

⑨ The presence of film inside causes thicker areas to shrink more. Traditional methods like holding pressure and overpacking won’t solve the shrinkage issue. The solution lies in reducing the material and making the part hollow.

IMD Injection Molding: Common Problems and Solutions

IMD (In-Mold Decoration) injection molding is a sophisticated process that demands accurate control over multiple variables to achieve optimal results. Here are some common challenges encountered in IMD injection molding and their corresponding solutions:

Common ProblemsCauses and Solutions







The pattern ink is scattered (washed) away during IMD injection molding
IMD ink is dry and doesn't let anything through. It has leftover solvents and air bubbles. When you're injection molding, the ink spreads and doesn't stick to the sheet as well.
IMD silver ink takes longer to dry
As the IMD sheet gets thicker, the area where the ink spreads out gets bigger.
It depends on whether the gate design has a good structure, shape, and distribution.
It depends on the plastic temperature. When the injection resin temperature goes up, the area that gets washed away goes down. The temperature setting depends on the plastic type and injection mold structure.
IMD ink layer printed too thin
IMD ink itself is not resistant to high temperatures
Failure to dehumidify the plastic before injection molding leads to the formation of bubbles during the process.

Incorrect viscosity adjustment of the ink prior to screen printing causes pinholes and uneven leveling in the ink layer.






IMD doesn't stick very well and the sheet comes apart easily.
There is residual solvent in the ink
The pressure, temperature, and cooling system of the injection molding machine are not properly regulated.
The silver ink is either overly saturated or incompatible with the injection molding process.
The ink doesn't stick to the substrate very well.
No printed IMD water-based adhesive
Mirror ink is too close to the curved edge
The plastic has moisture in it.
The adhesion of ink is related to the temperature of injection resin



Mirror ink has no mirror effect
The sheet (substrate) can't handle the solvents in the mirror ink.
It should be dried immediately after printing
Mirror ink should be printed with water-based adhesive
To make the ink stick better and get a mirror effect, add a hardener to the water-based adhesive. But use it all up within two hours of adding the hardener.


When embossing, the ink breaks
The corner of the punch is too sharp and should have a certain arc.
The ink isn't soft enough.
Improper viscosity adjustment of the ink can lead to issues... For instance, ink that dries too slowly may cause smudging during the process.

IML Injection Molding

Guide for Manufacturing of IML Injection Molding

What are the characteristics of IML process?

IMD/IML technology is an innovative in-mold decoration process that combines screen printing, molding, and injection molding. This method is the most efficient and cost-effective way to decorate products.

It is widely used across various industries, including communication products (such as mobile phone lenses, decorative parts, and casings), household appliances (window panels, button panels, and decorative panels), medical equipment (window lenses, casings, and decorative parts), and automobile dashboards.

IMD/IML products offer several advantages, including high definition, excellent three-dimensional effects, scratch-resistant surfaces, and the flexibility to change design patterns. They enhance the product’s appearance and reflect its perfect special-shaped structure. These technologies are widely used in applications such as mobile phone lenses and casings, where 3D design is crucial. IMD/IML overcomes the limitations of acrylic flat panels by enabling special-shaped effects and multiple color applications that were previously difficult to achieve.

In-mold decoration has become an excellent alternative to many traditional processes, such as thermal transfer, direct surface printing, direct electroplating, surface spraying, , and two-color injection molding. It is particularly suited for 3D products, especially those requiring consistent color registration, backlighting, multiple colors, and decoration on curved, cambered, or inclined surfaces.

What are the process steps of IML injection molding?

Trimming → Surface printing → Ink drying and setting → Applying protective film → Drilling positioning holes → Heat forming → Shaping peripheral edges → Injection molding procedure. The specific instructions are as follows:
  • Cutting:

Cut the rolled film into square blocks of the specified size for use in the printing and molding processes.

  • Flat Printing:
    Print the required icons and text onto the cut square film to create the film web.
  • Ink Drying and Fixing:
    Place the printed film squares in a high-temperature oven to dry and fix the IML ink.
  • Apply Protective Film:
    Apply one or two layers of protective film to prevent surface scratches during the punching of positioning holes.
  • Punch Positioning Holes:
    Accurately punch the positioning holes required for thermoforming. In some cases, the holes for the shearing process may need to be punched in advance.
  • Thermoforming (High Pressure or Copper Mold):
    After heating the printed film, use a high-pressure machine or copper mold to shape the film while it is still hot.
  • Cut the Peripheral Shape:
    Trim off the excess material from the formed three-dimensional film to create the desired shape.
  • Injection Molding Process:
    Place the molded film, which matches the exact three-dimensional shape of the front mold, onto the front mold and proceed with the injection molding to complete the IML product.

IML Injection Molding VS IMD Injection Molding

IML (In-Mold Labeling) and IMD (In-Mold Decoration) are widely used technologies in the packaging industry for decorating and labeling plastic products. While they share similarities, they differ in application and functionality. Below is a comparison of their key characteristics:
IMD Injecton MoldingIML Injecton Molding
IMD is suitable for large batches (100,000 or more)IML production batch quantity is very flexible

IMD products with three-dimensional molding height of IMD pattern not exceeding 1.5MM
IML technology is capable of handling diverse and intricate 3D productions, including flat surfaces, curved designs, and hemming applications. The molding height for 3D patterns can extend up to 40mm.


IMD products, because the ink is screen-printed on the surface, the fonts are not easily touched.
IML ink is screen-printed in the middle layer, so the appearance is smooth and beautiful, the more you touch it, the brighter it becomes. It has excellent scratch resistance, and the pattern and color can be changed at any time during production.
IMD can only screen print the same process as hot stamping paper, and cannot change its screen printing color.IML's ink colors are unlimited, and the screen printing color can be changed at will in the same batch of production.
IMD cannot make button productsIML can make products with buttons
IML has a relatively short development cycle, as molds for shaping, cutting, and injection can be developed concurrently alongside auxiliary processes. This efficiency allows for the simultaneous production of multiple components, reducing overall costs. Moreover, the absence of hooks enables the creation of thinner products.The overall development time of IMD is longer

What are the advantages and disadvantages of IML process

In-Mold Labeling (IML) is a widely used packaging technology in industries such as food, beverage, cosmetics, and pharmaceuticals. Below are the advantages and disadvantages of the IML process:

AdvantagesDisadvantages
Film production cycle is short and can express multiple colorsLong initial period
Patterns and colors can be changed at any time during productionIt is easy to cause the film to fall off, twist and deform, etc.
The outermost layer of IML is FILM, and the ink is screen-printed on the middle layer. The appearance is smooth and beautiful, the more you touch it, the brighter it becomes, and it has excellent scratch resistance.During the production process, the product defect rate is high
IML production batch quantity is very flexible and suitable for small-volume production of multiple varieties

The complete guide to IML injection molding

① Injection Molding Thickness:

  • It is recommended that the average flesh thickness should not be less than 1.2 mm (excluding the Film, the thickness should be 1.0 mm).

Film Thickness Specifications:

  • The standard thickness for film is 0.1 mm, 0.125 mm, and 0.175 mm.

Film Single-Piece Printing:

  • Single-piece printing is best suited for small production runs and situations requiring various design options.

Color Limitations:

  • This method is not recommended for metallic colors such as electroplated silver when the appearance color is bright silver, as temperature fluctuations may cause the film to peel off.

Film Edge Size:

  • The size of the film’s outer edge is directly linked to the size of the mold cavity. If the film edge is too small or too large, it can cause mold cavity stretching during injection and lead to edge leakage.

Minimum Hole Diameter:

  • The minimum diameter for round holes on the lens is Φ1.0 mm.

Lens P.L Position:

  • The P.L of the lens is typically positioned at the bottom. If there are issues with the draft angle, it can be located 0.2 mm from the lower edge of the film coating.

Lens Draft Angle:

  • The draft angle for the lens is generally 3 degrees.

Lens Appearance:

  • For lenses with differing appearances, the film must be pre-formed before the injection molding process.
4o mini

⑩ Rounded Corner Design:

  • IMD/IML molding cannot create sharp edges. The appearance outline should avoid sharp corners, and all corners must have a rounded radius of at least 0.3R.

Hemming Issue:

  • Hemming refers to the edge where the film and plastic meet, which may not be very clean after injection molding. To address this, the product design can incorporate plastic parts to cover the edge where the film and plastic connect.

Requirement for Surface Wear Resistance Hardness:

  • The product surface must achieve a wear resistance hardness rating of above 3H to guarantee long-term durability.

How to test and verify IML products?

Testing and verifying IML (In-Mold Labeling) products is crucial to ensure they meet required standards and specifications. Here are key methods to test and verify IML products:

Hardness Test:

  • Use a polished 2H~3H pencil with a 500g force and push it flatly towards the surface of the product at a 45-degree angle. If the surface shows no obvious scratches or marks, it is considered qualified.

Temperature Test:

  • Place the product in a furnace with a relative humidity of 95%-100% and a temperature of 57±3°C for 48 hours. If there is no bursting, discoloration, deformation, color loss, or loss of function, it passes the test.

Wear Resistance Test:

  • Rub a rubber with a 500g weight back and forth 300 times (one back and forth equals one cycle) at the same spot, with a length of 2 inches. If no obvious wear or degradation occurs on the surface, it is considered qualified.
Sand Washing Test:
  • The fixed test coating is placed at a 45-degree angle with the friction instrument. The coating surface is washed using the specified sand amount and flow rate (2 liters/21~23.5 seconds) until 500ml of sand grains have been applied. If the material beneath the paint becomes visible after washing with 500ml of sand, it is considered a serious defect. If it becomes visible after 100ml of sand, it is considered a minor defect.
  • If minor defects exceed 20% of the total samples or if serious defects exceed the total number of samples, the product is considered unqualified.
Optimization Solutions Provided For Free
  • Provide Design Feedback and Optimization Solutions

  • Optimize Structure and Reduce Mold Costs

  • Talk Directly With Engineers One-On-One

Plastic Injection Molding Machine

Please send email to sales@kingstarmold.com or fill out the contact form below if you have any questions or want to get a quote.

First Name*

Last Name*

Email Address*

Describe Your Project*

Go to Top