Pump Guiding Rod Production via Segmented Molding and Heading

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Solution Overview

Problem

The existing method for producing guiding rods for cosmetic product pumps involves complex and expensive molds with mobile compartments, leading to difficulties in demolding and potential damage to the sealing connection between the flexible membrane and the guiding rod.

Innovation Solution

A method that simplifies the production process by using a single-plate mold for plastic injection molding of the cylindrical rod, followed by a shape correction step to form the rod head without adding material, such as hot or cold heading, allowing for easy demolding and avoiding joint planes that could damage the membrane sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a mold with mobile compartments is used to produce the rod with head, then the rod can be formed with the head structure, but the demolding becomes difficult and requires lateral movement of compartments, creating joint planes that damage membrane sealing

Engineering Contradiction:

Improverod head structureVSAvoiddemolding process

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The production process is segmented into two independent stages: first molding the cylindrical rod body without head, then separately forming the head structure. This separates the molding and head-forming operations, allowing simple axial demolding of the rod body while the head is added afterward, eliminating the need for complex lateral compartment movement during demolding

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cylindrical rod body is preliminarily formed without the head structure during the injection molding stage. This preliminary action allows the rod to be easily demolded in one piece, and the head structure is subsequently added through a separate heading process, avoiding the demolding difficulties that would arise from trying to form the head during initial molding

Inventive Principle:

Principle #10Preliminary action

2Shape

If a mold with mobile compartments is used, then the rod with head can be produced, but the mold becomes complex and expensive to produce

Engineering Contradiction:

Improverod head structureVSAvoidmold structure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The production system is segmented into a simple injection molding stage that produces only the cylindrical rod body, followed by a separate heading stage that forms the head. This segmentation allows the use of a simple, single-plate mold without complex mobile compartments, significantly reducing mold complexity and cost while still achieving the final rod-with-head geometry

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of forming the head during the injection molding process (which would require complex molds), the approach is inverted: the rod body is molded first with a simple mold, and the head structure is subsequently formed through a heading process. This inversion simplifies the mold design while achieving the same final product geometry

Inventive Principle:

Principle #13The other way round (Inversion)

3Shape

If the rod is molded with head in one piece, then the rod structure is complete, but joint planes are created that deteriorate the sealing of the flexible membrane connection

Engineering Contradiction:

Improverod head structureVSAvoidmembrane sealing

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The rod production is segmented into two stages: molding the cylindrical body without head, then separately forming the head through heading. This segmentation eliminates the joint plane that would be created by molding the head and body as one piece, because the rod body is molded as a single continuous piece without interruptions, preserving the integrity of the membrane sealing surface

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cylindrical rod body is preliminarily molded as a complete, continuous structure without the head. This preliminary action ensures that the rod body has no joint planes that could compromise sealing, and the head is subsequently added through a separate process that does not interfere with the sealing surface of the rod body

Inventive Principle:

Principle #10Preliminary action

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 reduces production costs, eliminates the risk of damaging the membrane sealing, and improves pump functionality by enabling a smooth, cylindrical rod design that can be easily demolded and shaped without compromising the membrane's integrity.

Implementation Method 1

a plastic injection molding step to form the cylindrical rod

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

a plastic injection molding step to form the cylindrical rod

Methodology Applied

Scientific EffectCooling: Cooling

Implementation Method 3

a step of correcting the shape of an upper end of the rod, so as to form the head by creating a shoulder

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS11548193B2Method for producing a guiding rod for a pump

Publication Date: 2023.01.10 SILGAN DISPENSING SYST LE TREPORT

AI summary

The invention relates to a method for producing a guiding rod for a pump for dispensing a fluid product. The rod includes a cylindrical body surmounted by a head. The method a plastic injection molding step to form the cylindrical rod. The method also includes a step of correcting the shape of an upper end of the rod so as to form the head by creating a shoulder at the level of the junction between the head of rod and body.