Panel-Shaped Molded Product With Thickness Gradient Frame
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Solution Overview
Problem
Current panel-shaped molded products for automobile windows face issues with resin bleed-out and fine distortions due to shrinkage of the frame part, leading to compromised finishing accuracy and appearance.
Innovation Solution
A laminated structure is adopted where the design part is injection-molded first, followed by the frame part, with a thickness changing region in the frame's inner peripheral portion to reduce shrinkage forces and prevent resin bleed-out, ensuring the frame part's thickness is reduced towards its center, and specific ratios of the thickness and width of this region are controlled to minimize distortions on the design part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the frame part is injection-molded first to prevent deformation of the design part, then the design part can be protected from shrinkage deformation, but resin bleed-out occurs at the inner periphery of the frame part
Solution Approach 1:
The patent inverts the conventional molding sequence by injection-molding the design part first and then the frame part. This reversal prevents resin bleed-out because the design part is already in place to block resin flow, while still achieving the goal of preventing deformation through proper sequence control.
Solution Approach 2:
The patent introduces a thickness changing region with a specific gradient in the frame part's inner peripheral portion. This local variation in thickness (with specific ratios L2/t2 and L2/L1) creates different structural properties in different regions, allowing the frame part to prevent resin bleed-out while controlling shrinkage forces to avoid deformation of the design part.
2Manufacturing precision
If the frame part is injection-molded first to prevent deformation, then shrinkage forces are controlled, but fine distortions occur on the design part due to shrinkage of the frame part
Solution Approach 1:
By reversing the molding sequence to mold the design part first, the patent eliminates the harmful effect of frame shrinkage on design part shape, as the design part is already solidified and protected when the frame is subsequently molded.
Solution Approach 2:
The thickness changing region with specific gradient ratios creates localized structural characteristics that control shrinkage forces. The gradual thickness reduction (with L2/t2 ≥ 0.4 and L2/L1 ≥ 0.4) in the inner peripheral portion of the frame part manages stress distribution, preventing fine distortions on the design part surface while maintaining overall structural integrity.
3Object-generated harmful factors
If the design part is injection-molded first to prevent resin bleed-out, then resin flow is blocked, but strong shrinkage of the frame part adversely affects the design part
Solution Approach 1:
The patent adopts the inverted molding sequence (design part first, then frame part) which naturally blocks resin bleed-out at the inner periphery of the frame part, as the design part serves as a physical barrier to resin flow during frame part injection.
Solution Approach 2:
The thickness changing region with controlled gradients (L2/t2 ≥ 0.4 and L2/L1 ≥ 0.4) in the frame part's inner peripheral portion creates a structural transition zone that reduces shrinkage forces. This local quality variation allows the frame part to achieve adequate strength while minimizing adverse shrinkage effects on the previously molded design part.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents resin bleed-out and fine distortions on the design part, enhancing the finishing accuracy and appearance of the panel-shaped molded product, suitable for high-precision applications like automobile windows.
Implementation Method 1
a frame part (2) is injection-molded on one surface of the plate-shaped design part (1)
Implementation Method 2
when the transparent resin for the design part (1) is injected on the frame part (2), the opaque resin for the frame part (2) which is present at a boundary coming into contact with a flow of such a transparent resin for the design part is melted out
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3(a)~3(c)
AI summary
The present invention relates to a panel-shaped molded product having a laminated structure which is produced from a resin and used for side doors, back doors, hoods, roofs, etc., and exhibits a more excellent finishing accuracy without occurrence of bleed-out along an inner periphery of a frame part and fine distortions on a design part. The panel-shaped molded product of the present invention is a molded product having a laminated structure which is obtained by injection-molding the frame part (2) on one surface of the plate-shaped design part (1) wherein an inner peripheral portion (4) of the frame part (2) is closely attached to the design part, and has a thickness changing region where a thickness of the frame part is reduced toward the side of a center of the frame part such that a ratio between a width of the thickness changing region and the thickness of the frame part (2), and a ratio between a width of the thickness changing region and a width of the frame part (2) are respectively adjusted to satisfy specific relationships.