IMD Injection Sequence Inversion for Sinkhole Prevention
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Solution Overview
Problem
In the IMD injection process, defects such as sinkholes often occur on the visible face of parts due to the structural part not having time to cool and solidify completely before the support layer is injected, leading to poor quality control.
Innovation Solution
The process is modified to first inject the support layer, followed by the structural part, with a frame holding the support sheet against the mold and a movable locking member ensuring the support layer is fixed initially, allowing for controlled injection and solidification of the structural part without defects on the visible face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the structural part is injected before the support layer to maintain high production speed, then productivity is improved, but the structural part does not have time to cool and solidify completely, leading to shrinkage defects on the visible face
Solution Approach 1:
The patent inverts the conventional injection sequence by injecting the support layer first and then the structural part. This reversal allows the structural part to cool and solidify properly without causing shrinkage defects on the visible face, while the support layer acts as a protective barrier during the process.
Solution Approach 2:
The support layer is injected and allowed to partially cool before the structural part is injected. This preliminary action creates a stable base that prevents shrinkage defects during the subsequent injection of the structural part, ensuring quality of the visible face.
2Manufacturing precision
If the support layer is injected first to prevent shrinkage defects on the visible face, then manufacturing precision is improved, but the mold structure and process complexity must be increased to hold the support sheet and enable sequential injection
Solution Approach 1:
The mold is segmented into multiple cavities, with the first cavity used for injecting the support layer and the second cavity for injecting the structural part. This segmentation allows sequential injection while maintaining a relatively simple overall mold structure.
Solution Approach 2:
The mold includes movable locking members that can dynamically adjust to hold the support sheet in place during the first injection, then release to allow the second injection. This dynamic mechanism enables the complex process sequence without requiring a permanently complex mold structure.
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 ensures that the support layer is injected before the structural part, preventing sinkholes on the visible face and improving the overall quality control of the manufactured parts.
Implementation Method 1
pinching the support sheet against a first part of the mold by a frame
Implementation Method 2
the structural part is generally more massive. In the case of a high-speed manufacturing process, if the structural part is injected before the support layer, it does not have time to cool and solidify completely
Data Source
Figure 1
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AI summary
The part (1) comprises a support layer (3), a decoration layer (5) and a structural part (7). The process comprises the following steps: - introduction into a mold (9) of a support sheet (11) bearing the decoration layer (5); - clamping of the support sheet (11) against a first part (13) of the mold by a frame (15); - closing of the mold (9), a first surface (27) of the first mold part (13) and a second surface (29) of a second mold part (25) together defining a cavity (31); - injection of the support layer (3) into the cavity (31) and transfer of the decoration layer (5); - opening of the mold (9), the support layer (3) remaining fixed to the first mold part (13) by at least one movable locking member (33) mounted on the frame (15);- closing of the mold (9), the first surface (27) of the first mold part (13) and another second surface (35) of another second mold part (37) together delimiting another cavity (39); - displacement of at least one blocking member (33) relative to the frame (15) to a position for releasing the support layer (3); - injection of the structural part (7) into the other cavity (39) and evacuation of the part (1).