Overmolded Electronic Eyewear Frame with Segmented Wall Structure
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Solution Overview
Problem
The existing injection molding processes for electronic eyewear devices often result in sink marks due to uneven wall thicknesses and face challenges in integrating additional electronics, which increases cycle time and may require detrimental temperatures, affecting the integrity of components.
Innovation Solution
An overmolding process where a frame insert made of a first material is attached to a mold without contacting other areas, and a second material is used to partially encase it, minimizing wall thickness variations and allowing for the integration of electronics while maintaining the integrity of the component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional injection molding is used to form the frame, then the manufacturing process is simple, but sink marks occur due to uneven wall thicknesses
Solution Approach 1:
The frame is divided into a base frame structure and separate wall portions that are formed independently through the overmolding process. This segmentation allows each wall portion to be precisely controlled for thickness and surface quality while maintaining the overall frame structure, eliminating sink marks caused by uneven wall thicknesses in traditional single-step injection molding.
Solution Approach 2:
The base frame is pre-formed and positioned in the mold before the wall portions are injected. This preliminary action establishes the frame structure first, allowing subsequent wall portions to be added with controlled thickness and uniform surface quality, preventing sink marks that would occur if all portions were molded simultaneously.
2Adaptability or versatility
If additional electronics are integrated into the frame, then the device functionality is enhanced, but the cycle time increases and temperatures may affect component integrity
Solution Approach 1:
Electronics are nested within recesses or cavities formed in the base frame structure before the wall portions are overmolded. This nesting approach allows electronics to be integrated without requiring separate molding steps, as the wall portions are formed to enclose the electronics simultaneously with the frame structure, maintaining cycle time while enabling functionality enhancement.
Solution Approach 2:
The molding process uses controlled temperature parameters and pressure variations during the overmolding phase to accommodate electronics integration. By adjusting these parameters during the wall portion formation, the process can enclose electronics without subjecting them to detrimental temperatures, thus integrating functionality while preserving component integrity and managing cycle time.
3Strength
If wall thickness is increased to improve structural integrity, then the frame strength is enhanced, but the appearance quality deteriorates due to visible thickness variations
Solution Approach 1:
Different wall portions are formed with locally optimized thicknesses that provide sufficient structural integrity at critical locations while maintaining uniform appearance at visible surfaces. The overmolding process allows selective thickness control in different regions, enabling strength enhancement where needed without compromising surface uniformity and appearance quality.
Solution Approach 2:
The frame combines a base frame material with overmolded wall portion materials that have different properties. This composite structure allows the base frame to provide structural integrity while the overmolded wall portions provide uniform surface appearance, as the second material can be precisely controlled to eliminate thickness variations visible on the exterior surface.
Data Source
AI summary
A process of overmolding a frame of a portable eyewear electronic device and a frame produced by the process is presented. A frame that includes a first material and includes a releasably mountable feature is attached to the mold in a desired position and does not contact other areas of the mold. The mold is filled with a second material to at least partially encase the frame insert.