Resin Pipe Joint Molding With Gas-Venting Mold Gap
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Solution Overview
Problem
Conventional resin pipe joint manufacturing methods often result in molding defects due to trapped gases within the mold cavity, leading to insufficient filling and surface roughness, and increasing filling pressure can cause appearance defects such as flow marks.
Innovation Solution
A method involving a mold design with a gap between the second mold and the first mold to allow gas escape, ensuring that molten resin can infiltrate the cavity without gas entrapment, and a structure including inner and outer sleeves with sealing regions to enhance connection and sealing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If filling pressure of molten resin is increased to avoid insufficient filling of the cavity, then filling completeness is improved, but appearance quality deteriorates due to flow marks on the surface
Solution Approach 1:
The patent extracts the harmful gas from the cavity by providing a dedicated gas discharge path through the second mold. The gap between the second mold and cavity wall creates a channel that allows gas to escape during injection, eliminating the need to increase filling pressure and thus avoiding flow marks while ensuring complete filling
2Reliability
If gas is allowed to escape from the cavity through a gap in the second mold, then gas entrapment is prevented, but mold structure complexity increases
Solution Approach 1:
The second mold is designed with local quality variation: most of the mold structure remains simple and robust, but a specific local region includes a controlled gap for gas discharge. This localized modification provides the necessary gas escape function without significantly increasing overall mold complexity
Solution Approach 2:
The patent changes the geometric parameter of the second mold by introducing a controlled gap dimension. This parameter change creates an effective gas discharge path while maintaining the simplicity of the overall mold structure. The gap size is optimized to allow gas escape while preventing resin leakage
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 prevents gas entrapment, ensuring complete cavity filling and reducing molding defects, thereby improving the quality and appearance of the resin pipe joint.
Implementation Method 1
The second mold has an outer periphery with a gap that connects the cavity to a discharge space outside the cavity and allows gas to flow when the second mold is combined with the first mold
Implementation Method 2
when molten resin is supplied to the mold and infiltrated into the cavity, gas generated in the cavity due to the injection of molten resin and/or gas (air) existing in the cavity before the supply of molten resin can escape to a discharge space of the cavity through the gap
Implementation Method 3
Solidifying molten resin in the cavity after stop of the supply of molten resin from the supply device
Data Source
AI summary
A method for manufacturing a resin pipe joint with a joint body includes the following steps. Preparing a mold and a supply device configured to supply molten resin. The mold includes a first mold for an outer shape of the joint body and a second mold for an inner shape of the joint body. Combining the second mold with the first mold to form a cavity, into which the molten resin is injectable, inside the mold. Supplying the molten resin to the cavity in the mold. Solidifying the molten resin in the cavity after stop of the supply of the molten resin from the supply device. The second mold has a gap that connects the cavity to a discharge space outside the cavity and allows gas to flow.