Conical Jaw Ring Mold Assembly for PET Preform Abrasion

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Solution Overview

Problem

The existing mold assemblies for PET preform production suffer from abrasions on conical locking surfaces, leading to deformation and increased costs due to the need for complete replacement of mold parts, which is inefficient in terms of raw material, labor, and energy consumption.

Innovation Solution

A mold assembly design that integrates conical jaw, cavity, and locking rings, allowing for selective replacement of worn-out rings and using laser welding to repair conical surfaces, thereby preventing the need for full replacement of the locking ring, jaw, or cavity during abrasion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mold assemblies are used for PET preform production, then the mold structure is simple and easy to manufacture, but abrasions occur on conical locking surfaces causing deformation and requiring complete replacement of mold parts

Engineering Contradiction:
Improvedurability of conical locking surfacesVSAvoidcomplexity of mold assembly structure
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The mold assembly is divided into separate functional components: a stationary part containing the conical locking surface, and a movable part with replaceable conical jaw rings. This segmentation allows the locking surface to be protected while enabling replacement of only the worn jaw rings rather than the entire mold part, resolving the contradiction between durability and manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conical jaw rings are designed with specific local properties (hardness, wear resistance) tailored for the locking function. These rings can be manufactured with optimized local quality characteristics and replaced independently when worn, allowing the overall mold structure to remain simple while achieving high reliability at the critical locking surfaces.

Inventive Principle:
Principle #3Local quality

2Reliability

If complete replacement of mold parts is performed due to abrasion, then the locking function is restored, but raw material consumption, labor, energy and time increase significantly

Engineering Contradiction:
Improvelocking surface functionalityVSAvoidraw material consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

Instead of discarding and replacing entire mold parts when abrasion occurs, the design allows for recovery and reuse of the main mold structure (stationary part and movable part body). Only the small, inexpensive conical jaw rings are replaced when worn, dramatically reducing raw material consumption while restoring locking functionality.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The conical jaw rings are extracted as separate, replaceable components from the main mold assembly. This extraction allows the critical locking function to be maintained by replacing only the worn rings rather than the entire mold parts, reducing material loss while ensuring reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If complete replacement of mold parts is performed due to abrasion, then the locking surface functionality is restored, but production time and energy consumption increase

Engineering Contradiction:
Improvelocking surface functionalityVSAvoidproduction downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By segmenting the mold into replaceable jaw rings and a permanent main structure, maintenance time is dramatically reduced. When abrasion occurs, only the small jaw rings need to be replaced rather than the entire mold assembly, significantly reducing production downtime while restoring locking functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The main mold structure is recovered and reused indefinitely, with only the small, quickly replaceable jaw rings being discarded when worn. This approach minimizes production downtime and energy consumption associated with manufacturing new mold parts while ensuring continuous reliable operation.

Inventive Principle:
Principle #34Discarding and recovering

4Reliability

If conical jaw rings are integrated into the jaw structure, then the locking ring is protected from abrasion, but the device complexity increases

Engineering Contradiction:
Improveprotection of locking ring from abrasionVSAvoidmold assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protection mechanism is implemented through segmentation - conical jaw rings are inserted into jaw channels on the movable part, creating a modular structure. This segmentation protects the main locking ring from direct contact and abrasion while adding minimal complexity through the use of simple, standardized ring components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conical jaw rings act as intermediary elements between the movable part and the locking ring. These intermediaries absorb the wear and friction, protecting the main locking ring from abrasion while adding only minimal structural complexity through their simple ring geometry and insertion mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively eliminates abrasion-related deformities in PET preforms by allowing for targeted replacement and repair of conical surfaces, reducing material and energy consumption, and maintaining production efficiency.

Implementation Method 1

make fillet welding by applying suitable weld seams to the worn conical surfaces of the jaw, cavity, locking ring and core by laser welding machine or other welding methods

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3999305B1Mold assembly for the production of pet preform and similar plastic products
Publication Date: 2024.09.04 FR MECHANICAL ENG CO LTD
  • EP3999305B1 patent drawingFigure 1
  • EP3999305B1 patent drawingFigure 2
  • EP3999305B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a mold assembly used in the production of plastic injection pet preforms and similar plastic products. The invention comprises the jaw (10) that forms the mouth of the PET preform on the injection mold and has the first conical jaw ring (70) on one side and the second conical jaw ring (80) on the other side, the cavity (20), which is locked to the side of the jaw (10) with the first conical jaw ring (70), by means of the cavity ring (50) connected to the upper surface and forming the outer wall of the PET preform, the locking ring (40) that is locked to the side of the jaw (10) with the second conical jaw ring (80) by means of the core ring (60) connected to its upper surface, the core (30) that is connected on the locking ring (40) and forms the inner wall of the PET preform.