Insert Edge Reinforcement via Segmented Injection Molding
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Solution Overview
Problem
Existing injection molding processes face challenges in creating a firm and reliable connection between inserts and plastic bodies due to material instability and pressure-induced displacement during the molding process, particularly when using complex tools with multiple movable parts.
Innovation Solution
A two-component injection molding process using a first and second mold section to form a first and second plastic body part, with a web creating a passage for the second melt to flow, allowing nozzle placement on the same side and ensuring a firm bond between the insert and plastic body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex injection molding tool with multiple independently movable cavity-forming tool parts is used to fix the edge area, then the plastic body can be molded onto the insert edge, but the device complexity increases significantly
Solution Approach 1:
The plastic body is divided into two separately moldable parts: a first plastic body part molded in the first mold section, and a second plastic body part molded in the second mold section. The web creates a recess in the first part that connects to the second cavity, allowing the second melt to flow through and bond the parts together. This segmentation eliminates the need for complex movable tool parts while ensuring reliable connection.
Solution Approach 2:
The web acts as an intermediary structure that creates a recess in the first plastic body part. This recess serves as a passage for the second plastic melt to flow through, creating a bonding interface between the two plastic body parts. The web structure mediates the connection without requiring complex movable tooling.
2Strength
If materials are overmolded onto the insert edge, then the edge strength is enhanced, but the materials may be forced away uncontrollably by the injection pressure
Solution Approach 1:
The overmolding process is segmented into two separate injection steps: first molding the first plastic body part in the first mold section, then molding the second plastic body part in the second mold section. The web creates a recess that allows the second melt to flow through and bond to the first part. This segmentation reduces the pressure on any single material layer, preventing uncontrollable displacement while still achieving enhanced edge strength.
3Reliability
If the edge area is completely enclosed by the plastic body on both sides and across the end face, then the connection reliability is improved, but the tool complexity increases with multiple movable parts
Solution Approach 1:
The first and second plastic body parts are merged through the web structure, where the recess in the first part connects to the second cavity. The second plastic melt flows through the recess and bonds the two parts together, creating a unified structure that encloses the edge area on both sides and across the end face. This merging achieves complete enclosure without requiring multiple independently movable tool parts.
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
The process ensures a stable and permanent bond between the insert and plastic body, enhancing the structural integrity of the edge region while allowing efficient nozzle placement and reducing tool complexity.
Implementation Method 1
Injecting a first plastic melt into the first circumferential cavity to produce a first circumferential plastic body part
Implementation Method 2
injecting a second plastic melt into the second mold section so that the second plastic melt flows through the recess of the first plastic body part, fills the second cavity, and thus forms the second plastic body part
Implementation Method 3
The two parts are firmly bonded together at the end face of the edge area of the insert, thus forming the circumferential plastic body
Data Source
Figure 1(a)~2(b)
Figure 3~4
AI summary
The invention relates to a method for producing a product comprising a cup-shaped insert part (3) with a circumferential edge to be reinforced and a circumferential plastic body (4) which is injection-molded onto the edge, said plastic body (4) surrounding an edge region (31) of the cup-shaped insert part (3) on both sides and on the end face. The method has the following steps: a. providing a first mold part (1) of an injection molding tool; b. inserting the cup-shaped insert part (3) into the first mold part (1), wherein the first mold part (1) and the insert part (3) are designed such that a first circumferential cavity (11) is formed on the inner face and on the end face of the edge region (31) to be injection-molded, and the outer face of the edge region (31) of the insert part (3) rests against a wall of the first cavity (11); c. injecting a first plastic melt into the first circumferential cavity (11) in order to produce a first circumferential plastic body part (41), said first circumferential cavity (11) having a web (13) which forms a recess (43) in the first circumferential plastic body part (41) on the end face of the edge region of the insert part (4); d. providing a second mold part (2) of an injection molding tool; e. inserting the cup-shaped insert part (3) with the first circumferential plastic body part (41) into the second mold part (2), wherein the second mold part (2) is designed such that a second circumferential cavity (21) is formed on the outer face of the edge region (31) to be injection-molded in order to produce a second circumferential plastic body part (42), and the recess (43) in the first circumferential plastic body part (41) is connected to the second circumferential cavity (21); f. injecting a second plastic melt into the second mold part (2) so that the second plastic melt flows through the recess (43) of the first plastic body part (41), fills the second cavity (21), and thus forms the second plastic body part (42); and g. removing the product with a circumferential plastic body (4) consisting of the first and second plastic body part (41, 42) from the mold.