Plastic Preform Marking for Blow Molding Alignment

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Solution Overview

Problem

Existing plastic preforms used in blow molding processes face challenges in alignment and sealing due to the use of alignment cams and notches, which are difficult to access optically and can disrupt the blow molding process, especially when the preforms are made of transparent materials, leading to reduced performance and potential errors in processing.

Innovation Solution

A plastic preform design featuring a ring-shaped section with an optically perceptible marking on its underside, replacing alignment cams and notches, allowing for easier alignment and detection of the preform's rotational position, and facilitating the blow molding process by minimizing light disturbances and ensuring an undisturbed sealing surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If alignment cams and notches are used on the preform, then alignment during blow molding is achieved, but optical detection becomes difficult and sealing is disrupted

Engineering Contradiction:
Improveoptical detection of preform positionVSAvoidalignment mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical alignment system (cams and notches) with an optical marking system. The marking on the ring-shaped section provides optical detectability of preform position and orientation without requiring complex mechanical alignment features, thereby improving optical detection while reducing mechanical complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The ring-shaped section serves as an intermediary element that carries the optical marking. This mediator allows the detection system to identify preform position without direct interaction with the sealing surfaces or threaded area, resolving the conflict between detection needs and sealing integrity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If notches are made large to improve alignment visibility, then detection is easier, but sealing surface is compromised

Engineering Contradiction:
Improvealignment marking visibilityVSAvoidsealing reliability
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent moves the alignment marking from the sealing surface area to the ring-shaped section, effectively using a different spatial dimension. This allows large, easily detectable markings to be placed where they will not interfere with the sealing surfaces, thereby improving detectability without compromising sealing reliability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If the preform is made transparent to reduce light disturbance, then appearance is improved, but optical detection of markings becomes more difficult

Engineering Contradiction:
Improvelight disturbance through preformVSAvoidoptical marking detection accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies different optical properties to different parts of the preform. The ring-shaped section containing the marking has specific optical characteristics that enhance marking visibility, while other parts of the preform can remain transparent to minimize light disturbance. This localized differentiation allows both transparency and detection accuracy to be optimized in their respective areas

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2439034B1Plastic preform with marking for positioning
Publication Date: 2014.07.16 KRONES AG
  • EP2439034B1 patent drawingFigure 1~2
  • EP2439034B1 patent drawingFigure 3~4

AI summary

A plastic container (1), in particular a plastic preform (1), comprising a base body (2), a threaded section (4) arranged on the base body, wherein the threaded section (4) is formed integrally with the base body (2), and an at least partially annular section (6) arranged below the threaded section (4) and extending outwards in a radial direction (R) of the plastic container (1), and which is formed integrally with the base body, wherein the annular section has a first surface (6a) facing the base body (2) and a second surface (6b) facing the threaded section (4). According to the invention, at least one optically perceptible marking (10) is arranged on the surface (6a) facing the base body (2).