What Is Micro Injection Molding?

Micro injection molding is an ultra-precise manufacturing process involving thermoplastics. This complex process deals with shaping and forming thermoplastic products that are just a fraction of the size of a pellet, weigh a fraction of a gram or have microscopic features.

However, the term “micro” doesn’t only refer to the size of the products. It may also refer to other aspects of production, such as the tolerances and the features of the components being manufactured. These different production aspects will be discussed in more detail below.

The micro molding process is invaluable in the manufacturing industry as it enables the production of highly intricate, detailed plastic components – something that cannot be achieved using traditional injection molding methods.

Learn more about small part injection molding using the micro injection molding process below.

The Micro Injection Molding Process

The micro molding process begins with the manufacturer shaping the mold with small cavities based on the desired component. Once the mold is ready, liquid silicone rubber (LSR) is rapidly injected into the heated cavity, wherein it undergoes vulcanization to form the final part. 

However, the entire manufacturing process involves more than just a single small machine. Micro injection molding machines also come with sophisticated digital microcontrollers and temperature sensors to control the heat inside the mold, which is a crucial aspect of production. 

These sensors and controllers are more precise than those used in traditional injection molding due to the heightened requirements in the micro molding process. Meanwhile, the barrel is much shorter, making it easier and faster to clean when changing to new material. 

Some small part injection molding techniques may involve runners, channels that guide the material into the mold cavities. In contrast, direct gating methods do not require runners. Instead, they inject the material directly into the part, which reduces material waste.

Defining the “Micro” in Micro Molding

There are three key aspects involved in the micro molding process, which mainly pertain to the term “micro.” In this technique, micro can refer to the following:

• Product Size (Micro-Sized): In small part injection molding, manufacturers focus on producing “micro-sized” components, such as fasteners, connectors and medical components. 
• Component Features (Microfeatures): Some larger components may have features that can be considered micro-sized. This refers to parts with significant sizes that may contain intricate and precise elements. 
• Tolerances (Micro Tolerance): These refer to how narrow the margin of error is during mass production. Micro-molded components must adhere to strict production specifications, ranging from 1/100th to 1/1000th of an inch. 

Injection Molding vs the Micro Molding Process

Micro molding may be similar to its traditional molding counterpart, but it also has some distinct differences, including the following:

• More suitable for smaller, more complex products
• Special injection unit with a smaller shot size
• Micro molding machines are more precise
• Higher-resolution feed options
• Smaller cores, cavities and intricate features

3D Printing vs Micro Molding

3D printing is another method that produces complex components from plastic materials, hence the debate between 3D printing vs micro molding. Their fundamental difference lies in their production capacity, as micro molding tends to have faster production rates than 3D printing. This makes micro molding well-suited for high-volume manufacturing and 3D printing for rapid prototyping.

Advantages of Micro Injection Molding

Micro molding offers a wide range of advantages, including the following:

Capable of Mass-Producing Complex Components

Injection molding technology enables manufacturers to produce high volumes of components while retaining their complex geometries with great precision. These production capabilities are crucial in manufacturing products for industries where slight deviations can hinder performance. These include electric components, micro-optics, medical devices and more. 

Supports a Wide Range of Material Options

Micro injection molding works with a wide range of material options to produce products that offer excellent mechanical properties, thermal stability and chemical resistance. It uses materials like high-performance polymers and engineered thermoplastics tailored to the specific application. This versatility ensures that all manufactured products meet the intended application’s functional requirements.

Offers Significant Cost Advantages

Injection molding techniques are widely used due to their significant cost advantages. But micro injection molding offers even higher cost savings in the following ways:

• Lower tooling requirements for smaller products allow manufacturers to use smaller, less expensive machines.
• Smaller product sizes allow for more efficient usage of materials, minimizing waste. 
• Shorter production cycles make production faster and more cost-effective.
• High-efficiency machines can integrate multiple steps in a single production cycle, significantly reducing the overall manufacturing time. 

Applications of the Micro Molding Process

The enhanced production capabilities of micro injection molding are helpful in applications where size and precision matter. These are particularly advantageous in the following industries:

• Medicine and Healthcare: The healthcare industry demands extreme accuracy in producing complex instruments used for patient care. These include devices used for diagnostics, catheters, drug delivery and sensory aid, among others.
• Electronics: Complex parts like microchips, laser optics, prisms, switches, connectors and other components for electronic devices.
• Automotive and Aerospace: The automotive and aerospace industries rely on micro molding techniques to produce lightweight and compact parts, such as engine components, brakes, washers, clips, door-locking mechanisms, switches and buttons.
• Industrial Automation: Micro molding produces small precision components from various engineering materials for compact and efficient automation systems.
• Defense and Security: The micro molding process accommodates the production of diverse components while accounting for the weight and durability requirements of portable defense and security equipment. 

Improve and Advance Your Manufacturing Processes With All-Plastics

Micro injection molding delivers many benefits for numerous industries that significantly enhance manufacturing efficiency and productivity. Across the board, these benefits empower enterprises to push the boundaries of innovation to help them become even more competitive in today’s market. 

All-Plastics enhances your manufacturing capabilities by providing the latest micro injection molding technology. As a leader in advanced manufacturing and project management, we take advantage of cutting-edge technologies to manufacture products in a zero-defect environment. Please fill out our online contact form to request a quote or more information about our services.