Bonded Seal Elevation Geometry for Gas-Tight Injection Molding
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Solution Overview
Problem
Existing injection molded parts with thermoplastic inserts and composite elements face issues with incomplete melting of elevations due to insufficient melting energy, leading to unreliable gas-tight connections and increased space requirements.
Innovation Solution
The method involves designing elevations with a first slope on the melt flow inflow side and a second slope on the outflow side, with specific angle ranges to enhance heat transfer and melting, and using a single annular elevation for cylindrical parts to achieve a gas-tight connection while minimizing space and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elevations are designed with sharp edges perpendicularly on the interface, then the construction is simple, but the melting energy is insufficient and reliable gas-tight connection cannot be achieved
Solution Approach 1:
The elevation is designed with different local geometries: a first slope on the melt flow inflow side with angle α between 5° and 45° to facilitate melt flow and heat transfer, and a second slope on the outflow side with angle β between 50° and 75° to prevent gas inclusions. This local differentiation of geometric properties ensures both reliable melting and gas-tight connection without excessive complexity.
Solution Approach 2:
The invention changes the geometric parameters of the elevation from sharp perpendicular edges to controlled slopes with specific angle ranges. The first slope angle α (5°-45°) and second slope angle β (50°-75°) are optimized parameters that enable sufficient heat transfer and melting while maintaining structural integrity and gas-tightness.
2Reliability
If several elevations are arranged one behind the other in the direction of melt flow, then gas-tightness is improved, but the space requirement increases
Solution Approach 1:
The invention merges the functions of multiple elevations into a single integrated elevation structure. By providing a first slope for heat transfer and a second slope for gas exclusion, one elevation performs the work that previously required multiple elevations, thereby achieving gas-tightness with reduced space requirement.
3Loss of energy
If the constriction height H2 is large compared to elevation height H1, then the melt flow is not sufficiently constricted, but heat transfer to the elevation is insufficient
Solution Approach 1:
The invention optimizes the geometric parameters by defining specific angle ranges for the slopes rather than using simple height ratios. The first slope angle α (5°-45°) and second slope angle β (50°-75°) provide precise control over melt flow constriction and heat transfer efficiency, eliminating the need for large H2/H1 ratios while ensuring sufficient energy transfer.
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 reliable melting of elevations, improves heat transfer, reduces space requirements, and prevents gas inclusions, resulting in a more efficient and cost-effective production of injection molded parts with enhanced sealing capabilities.
Implementation Method 1
the transport of heat to the elevation and the direct heat transfer from the melt to the elevation are improved
Implementation Method 2
direct heat transfer from the melt to the elevation
Implementation Method 3
reliable melting of the elevation is thereby achieved
Implementation Method 4
the transport of heat to the elevation... are improved, and reliable melting of the elevation is thereby achieved
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Injection molded parts having at least one thermoplastic insert and a thermoplastic composite element molded onto the insert are already known, wherein the at least one insert has multiple raised areas configured as fusing points, which are successively disposed in the melt flow direction at the boundary thereof to the composite element. The injection molded part is produced by means of an injection molding method, during which the insert is disposed in an injection molding tool and a composite element is integrally molded thereon. The raised areas are to be fused from the melt of the composite element such that a bonded, gas-tight connection is obtained. The invention provides that the at least one raised area (8) has a first slant (12) on the melt flow side (11) thereof, wherein the ratio of the height (H2) of the constricted cross-section (10) to the height (HI) of the raised area (8) is in the range between 0.6 and 0.9.