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5 Core Applications of Overmolding Injection Molds

As the core carrier for realizing multi material composite products, the design and application of encapsulated injection molds directly affect the product iteration speed of high-end industries such as medical, automotive, and consumer electronics. According to statistics, the global market size of encapsulated injection molds has exceeded 38 billion US dollars by 2025, an increase of 165% compared to 2020. Its technological evolution trajectory is deeply coupled with the demand for industrial upgrading.

The innovative application in the field of medical devices is the most significant breakthrough direction of encapsulation technology. By composite injection molding of TPE and PC, the anti slip and antibacterial functions of surgical instrument handles can be achieved. More noteworthy is the encapsulation process of microfluidic chip molds, which achieves 0.05mm precision PDMS microchannel formation within a 2cm ² area, reducing the cost of nucleic acid detection chips by 70%.

The tactile revolution of the intelligent cockpit in automobiles drives the upgrade of encapsulation mold technology. The new generation of car steering wheels commonly use a three color encapsulation process, with a PA66 reinforced skeleton as the bottom layer, a 50 Shore A elastic damping layer injected into the middle layer, and a TPV anti slip layer with laser etched patterns on the surface layer. The encapsulation of the transparent buttons on the dashboard is more precise, requiring a 0.15mm black TPU shading layer to be wrapped on top of a 0.3mm thick PMMA translucent layer, with a shading rate of up to 99.97%.

The breakthrough of waterproof structure in consumer electronics demonstrates the micrometer level control capability of overmolding injection molds. The sealing ring of the smart watch heart rate sensor requires a liquid silicone coating with a precision of 0.02mm on a ceramic substrate with a diameter of 5mm. The hinge wrap of the TWS earphone charging case further tests the dynamic fit of the mold, which needs to maintain dimensional stability within 0.1mm after 30000 opening and closing tests. This requires the thermal expansion coefficient difference of the mold insert to be controlled within 0.8 × 10 ⁻⁶/℃. The implementation of composite functions in industrial equipment relies on engineering innovation of encapsulated molds. AGV robot hub adopts metal insert rubber coating process, and 60 Shore D polyurethane layer is injected outside the aluminum alloy wheel core to increase the bearing capacity by three times and reduce the noise by 15dB. The high-voltage cable joint mold adopts the secondary rubber coating technology, first injection molding EPDM insulation layer and then coating CR anti-aging layer, so that the product weather resistance breaks through 100000 hours of ultraviolet aging test.

The upgraded experience of smart homes highlights the cross-border integration capability of encapsulation technology. The high-end coffee machine handle adopts a dual material packaging of wood grain PMD and food grade TPE, which not only maintains the touch of solid wood but also has high temperature resistance characteristics. The steam nozzle mold of a certain German brand uses an in mold visual positioning system to achieve precise alignment between the metal filter and the silicone sealing layer within 0.5 seconds, with an assembly error of ≤ 0.01mm. A more cutting-edge application has emerged in the field of intelligent mirrors, where a light guide strip is directly coated on a glass substrate to achieve seamless integration of touch sensing and ambient lighting.

The technological evolution of encapsulated injection molds is accelerating breakthroughs along three major directions: intelligence, micro nano, and functional integration. The quantum level mold temperature control system, which will be unveiled in 2025, can compress the temperature difference of 1600 independent temperature control zones to ± 0.1 ℃, ensuring perfect interface bonding of multi-layer materials. The new generation of mold cores using graphene reinforced mold steel have a service life that is more than four times longer than traditional H13 steel.