Plastic Micro Injection Molding

Realizing Plastic Micro Injection Molding with Proprietary Technology

We have established an ultrafine injection molding technology using plastic injection molding. We can achieve fine shapes that were previously considered impossible with conventional molding, all without laser processing or post-processing, using only injection molding.

For example, it is possible to manufacture ultrafine needles with tip diameters of several tens of microns, finer than hair (80 µm).

Applications of Micro Injection Molding Technology

We apply micro injection molding technology for various purposes, including the development of fine needles. We are capable of molding not only general-purpose resins such as PP (polypropylene) and PC (polycarbonate), but also biodegradable resins like PLA (polylactic acid) and PGA (polyglycolic acid), as well as medical-grade materials. If you have a specific resin in mind, we are also willing to undertake molding using that material. Please feel free to consult with us at your convenience.

The Mass Production of Hollow Microneedles

We have successfully achieved insertion into artificial skin with needles thinner than human hair using biodegradable resins. Please watch the video below to see the insertion process.

Micro-needle insertion video

Manufacturing Micro Needles for Drug Delivery to the Dermis Layer

Our technology boasts the precision to mold arrays of 16 hollow needles, each with a needle length of 1000 µm and an inner diameter of 50 µm, without defects.

The Difference Between Our Injection Molding Technology and Conventional Casting Methods for Hollow Microneedles

There are several methods for creating hollow microneedles from plastic. While casting is an example utilized by other companies, we are capable of producing with higher precision and mass production advantages through injection molding.

The Differences in Processes

Injection molding involves melting the resin material and injecting it into a mold under pressure, then cooling it to solidify. Casting involves dissolving the material in a solvent, pouring it into a mold, and then evaporating the solvent to solidify it.

Injection Molding is Suitable for Mass Production, While Casting is Suitable for Prototyping

Casting offers the advantage of inexpensive molds and easy material filling, allowing for a convenient start with minimal initial investment. While useful for prototyping, it is not suitable for mass production due to the long hours of evaporation required and the large space needed for product resting.

Furthermore, the volume reduction of evaporated solvent and the low density of the product lead to unstable elements such as voids and shrinkage, becoming bottlenecks in product stability during mass production. On the other hand, injection molding features various mechanisms in the mold, requiring considerable effort and cost for mold design and fabrication. However, solidification through cooling takes only seconds, enabling automation and significant cost reduction per unit, making it suitable for mass production. In terms of quality, stable molding is achievable as the material is melted and injected into the mold.

The Technological Capability to Mass Produce Hollow Microneedles through Injection Molding

Despite the clear advantages of injection molding, there are reasons why it is not commonplace.

Creating hollow microneedles via injection molding requires advanced technical capabilities, including the expertise to create intricate injection molds, precise control of factors such as injection pressure and temperature on injection molding machines, and delicate control over many factors.

One of our strengths is our advanced technical expertise in injection molding, allowing us to design products with mass production in mind from the prototyping stage.

The Benefits of Using Biodegradable Resins

Compared to metals and general-purpose resins, it offers higher safety.

The substance itself is not harmful, and even if it remains in the body, it gradually dissolves and exits the body.

Environmentally friendly (no waste disposal issues, etc.)

It can solve waste disposal issues because it is decomposed by microorganisms.

By selecting plant-based materials, you can contribute to CO2 reduction when using them.

During the production of raw materials, photosynthesis by plants significantly contributes to CO2 reduction.

Capable of Molding Hollow Needles Thinner than Metal

By making it thinner, we can reduce pain and lighten the burden on the user. (Image: Comparison with hair)

Cell Counting Plates with Higher Precision and Smoother Surfaces.

Through Micro Injection Molding, it is possible to not only achieve precision but also to finish the surface smoothly, enabling low-cost mass production.


    Grid lines are in the groove form.

  • Glass

    Grid lines are rough.

  • Other Companies

    Grid lines are convex.

In the left photo of the micro injection molded product and the glass-cut product, you can see a significant difference in the surface finish of the products. Additionally, in the case of plastic products from other companies, the grid lines are raised. The straightness and smoothness of the grid are superior to glass, making it easier to see fine details and preventing cells from getting caught. This enables the production of high-quality products such as cell counters and microscales.

Microfluidic Chips – Integration of Micro Injection Molding and Surface Modification Technologies

By bonding plates with finely grooved channels using surface modification techniques, it is possible to create sealed microfluidic chips without the need for heat or adhesives. This eliminates concerns about deformation of fine shapes due to heat, leakage of adhesive into the channels, and leaching of adhesive components. Applications such as localized drug reactions with cultured cells or biological tissues are expected.

Other Applications of Micro Injection Molding

Application Fields Examples of Products
Medical FieldLife Sciences Field DDSSurgical NeedlesLancet needle for blood glucose measurementMicro knifeCell cultureBeauty-related products Water-repellent and hydrophobic components
Electronics Components Field Micro pile structureLight guide plateWater-repellent and hydrophobic componentsAnti-reflective plate

Please feel free to inquire about “Customization, Development, Technology, OEM” consultation here!
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