Threaded Rotary Core for Pipe Injection Molding
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Solution Overview
Problem
Existing methods for producing pipes with internal threads and undercut geometries using injection molding are costly and inefficient, often requiring separate components and metal thread attachments, making it difficult to achieve reproducible and cost-effective production of pipes with defined internal threads and sealing geometries.
Innovation Solution
An injection molding device with a projectile carrier and a threaded rotary core that forms an internal thread by adjusting the embossing core within the article cavity, allowing for the production of pipes with undercut internal geometries and internal threads using thermoplastic molding compounds, where the rotary core is rotatable and translationally adjustable to create continuous thread turns without faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate components and metal threaded inserts are used to achieve internal threads in pipes, then threading functionality is achieved, but manufacturing complexity and production cost increase
Solution Approach 1:
The patent integrates the thread-forming capability directly into the projectile carrier used in the injection molding process. The embossing core on the projectile carrier creates internal threads during the single-shot molding process, eliminating the need for separate threading operations or metal inserts. This merging of functions allows threads to be formed as an integral part of the pipe during the base manufacturing process.
Solution Approach 2:
The thread geometry is prepared and formed during the initial injection molding process rather than as a subsequent operation. The embossing core pre-forms the thread structure while the thermoplastic material is still in its moldable state, allowing the threads to be created as part of the primary manufacturing step rather than requiring separate post-processing operations.
2Productivity
If metal threaded inserts or welded components are used to achieve sealing geometries, then sealing functionality is achieved, but production time and manufacturing steps increase
Solution Approach 1:
The patent combines sealing geometry formation with the thread-forming operation by integrating sealing elements into the embossing core structure. The sealing geometries are created simultaneously with the internal threads during the same injection molding cycle, eliminating separate sealing component attachment steps and improving production efficiency.
3Adaptability or versatility
If a fixed embossing core is used in the projectile carrier, then manufacturing simplicity is maintained, but adaptability to produce different thread geometries is limited
Solution Approach 1:
The patent employs an adjustable embossing core that can be positioned at different locations on the projectile carrier and configured to form various thread geometries. This dynamic adjustment capability allows the same tooling to produce different thread types and specifications by repositioning or reconfiguring the embossing core, providing versatility without requiring multiple dedicated tooling sets.
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
Enables the cost-effective and reproducible production of pipes with internal threads and undercut geometries, eliminating the need for separate components and metal attachments, resulting in pipes with defined internal threads and improved sealing geometries.
Implementation Method 1
an injection device for injecting a fluid against a projectile to be driven through the part cavity
Implementation Method 2
a tubular preform is extruded and drawn into a suitable blow molding tool
Data Source
Figure 1
AI summary
The invention relates to an injection molding device (1) for producing tubes having an internal thread, having a tool (2) forming an article cavity (3), having means for filling the article cavity (3) with a thermoplastic molding compound, having an injection device (6) for injection of a fluid against a projectile (13) to be forced through the article cavity, wherein the injection device (6) comprises a projectile (7) having at least one injection nozzle and having at least one projectile receptacle (8) for a projectile (13) as displacement body for the molding compound, wherein the projectile carrier (7) is provided on an end remote from the projectile receptacle (8) with a threaded stamping core (11) which is adjustable relative to the projectile carrier (7) between a thread-forming first position and a demolded second position, wherein in the thread-forming position the stamping core (11) penetrates into the article cavity (3) and seals the article cavity.