Blow-Molding Push Member Limits Barrier Layer Migration

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Solution Overview

Problem

During the manufacturing of plastic fuel tanks, the barrier layer in multilayer parisons tends to migrate to the welding zone, potentially compromising the integrity of the weld and the barrier function when forming welding spouts.

Innovation Solution

A process involving a push member and a moving plunger in a blowing mold that limits the migration of the barrier layer by adjusting the volume of the recess, ensuring the barrier layer remains distant from the welding zone, thereby maintaining its integrity and preventing damage during the welding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the parison is blown to form a welding spout, then the welding structure is created, but the barrier layer migrates to the welding zone compromising weld integrity

Engineering Contradiction:

Improvewelding spout formationVSAvoidweld integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A push member is positioned in advance within the recess to prevent barrier layer migration before the parison material flows into the welding spout area. This preliminary positioning ensures that when the material is blown and flows toward the recess, the barrier layer is already constrained and cannot migrate to the welding zone, thus maintaining weld integrity while still forming the welding spout structure

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The push member acts as an intermediary element between the recess and the parison material. It physically intervenes in the material flow process, pushing back the barrier layer and preventing its migration to the welding zone. This intermediary component enables the simultaneous achievement of welding spout formation and barrier layer protection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the barrier layer is kept distant from the welding zone, then weld integrity is maintained, but the recess volume is reduced

Engineering Contradiction:

Improveweld integrityVSAvoidrecess volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The push member is designed to be movable rather than fixed, allowing it to dynamically adjust its position based on the material flow during the blowing process. This dynamic positioning enables the push member to effectively prevent barrier layer migration while minimizing the reduction of recess volume, as the member can be positioned precisely where needed rather than occupying a large fixed space

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11305644B2Method for forming a welding spout on a parison during the blowing of a tank

Publication Date: 2022.04.19 PLASTIC OMNIUM ADVANCED INNOVATION & RES SA

AI summary

The invention relates to a tank of plastics material produced by blow-molding of a parison, incorporating a welding spout, of a shape projecting from its outer surface which has an edge configured to be welded to a corresponding edge of an attached part, the welding spout ending axially, on an inside of the tank, in a shape resulting from contact molding between the parison and a molding component, in which the welding spout ends axially on an outside of the tank in a shape resulting from contact molding between the parison and a molding component.