Micro injection molding

Micro molding

What Is Micro injection molding?

Micro molding is a specialized form of injection molding that focuses on producing extremely small, intricate plastic parts. These parts are often so tiny that they can’t be seen clearly with the naked eye or can only be handled using microscopes and precision tools

1. Process

Specialized plastic resins that can flow and fill extremely small features are chosen. Often, these materials have additives to enhance flowability.

Just as in standard injection molding, the plastic pellets are fed into a barrel and melted. Due to the small scale, the equipment and the melt channels are considerably smaller. Injection:

The molten plastic is injected into the micro-sized mold cavities. This requires precision equipment to control the injection pressure, speed, and volume to fill the tiny cavities accurately.

The plastic inside the micro mold cools and solidifies. Due to the small size, this might happen relatively quickly, but precision is key to prevent defects.

The micro-molded parts are ejected from the mold, often assisted by specialized ejection mechanisms. Key Characteristics: Precision and Accuracy: Micro molding machines are designed for extreme precision, often with tolerances in the microns.

The molds used for micro molding are highly specialized, often requiring advanced manufacturing techniques such as micro-machining or even laser etching to create the necessary details.

The amount of material being injected (shot size) is minuscule, requiring specialized equipment to handle these small volumes accurately.

Not all polymers can be micro molded. The material must have the right flow properties to fill the tiny mold cavities completely.

2. Advantages

Can produce parts with intricate details that can’t be achieved with standard injection molding.

Despite the small size, micro molding can produce large quantities of parts quickly.

Due to the small size, waste is minimized, and less material is needed.

3. Applications

Components for hearing aids, micro-catheters, surgical instruments, and other tiny medical devices or implants.

Micro connectors, sensors, and other components in the electronics industry.

Micro lenses and other optical components.

Creating prototypes or components for new technologies or scientific research.

4. Challenges

Any minor defect is magnified at this scale, requiring meticulous attention to detail and process control.

The precision required in micro molding often means higher costs for specialized equipment and molds.

Successfully micro molding parts often require specific expertise and a deep understanding of materials, tooling, and process parameters.


In conclusion, micro molding is a highly specialized branch of injection molding that caters to industries requiring tiny, precision components. While it comes with its unique set of challenges, advancements in technology and materials continue to push the boundaries of what’s possible in this field.

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