Injection Mold Gate with Recessed Protrusions for Light-Guide Plate Stress Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Injection molding of light-guide plates for LCD backlight units often results in deformation due to residual stress, leading to defects like pooling and white spots in the LCD panel, caused by uneven resin filling and cooling deviations in conventional die and mold designs.
Innovation Solution
A die and mold design featuring an upper and lower gate plate with recesses and protrusions, respectively, that allow for uniform resin injection and distribution, reducing residual stress through a tapered shape and increased width towards the cavity, thereby minimizing deformation and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection molding is used with a standard gate design, then the manufacturing process is simple, but residual stress causes deformation and defects in the light-guide plate
Solution Approach 1:
The gate is divided into multiple gate plates (first gate plate, second gate plate, third gate plate, fourth gate plate) with distinct functions. The segmentation allows each plate to be optimized independently - some for resin flow control, others for stress distribution - thereby reducing residual stress and deformation while maintaining manufacturing feasibility
Solution Approach 2:
Different regions of the gate structure are given different properties: the gate plates have varying thicknesses, the resin injection holes are strategically positioned, and protrusions are added to specific areas. This local differentiation optimizes resin flow distribution and stress concentration in critical areas, improving dimensional accuracy without requiring complete redesign of the entire gate
2Manufacturing precision
If resin is injected through a conventional gate, then the injection process is fast, but uneven resin filling causes pooling defects and white spots
Solution Approach 1:
The gate is segmented into multiple plates with multiple resin injection holes distributed across them. This segmentation creates multiple injection points that simultaneously fill different regions of the mold cavity, ensuring uniform resin distribution while maintaining efficient injection speeds without causing pooling defects
Solution Approach 2:
The gate plates act as intermediaries between the resin source and the mold cavity. By positioning multiple resin injection holes on different gate plates at specific locations, the system mediates resin flow to achieve uniform distribution in the cavity, preventing both pooling defects and white spots while maintaining productivity
3Stress or pressure
If the gate width is increased towards the cavity, then stress distribution improves, but the gate structure becomes more complex
Solution Approach 1:
The gate width is increased locally in specific regions where stress concentration occurs, rather than uniformly throughout. Protrusions are added to the gate plates at strategic positions to broaden the gate width in areas needing stress distribution, while other regions maintain simpler geometry. This localized modification improves shear stress distribution without requiring complete geometric complexity
Data Source
AI summary
A die and mold for manufacturing a mold product is provided. The die and mold includes a body having a cavity that has a shape corresponding to the mold product. The body includes an upper body plate, and a lower body plate facing the upper body plate and combined with the upper body plate. The die and mold also includes a gate. The gate includes an upper gate plate, a plurality of recesses formed on a lower surface of the upper gate plate, and a lower gate plate facing the upper gate plate. A plurality of protrusions is formed on an upper surface of the lower gate plate in a location corresponding to a location in which the plurality of recesses is formed. The gate also includes a resin injection portion through which a resin is injected into the cavity.