Movable Blow Mold Regions for Sharp Edge Formation

Solution Overview

Problem

Existing blow-molding methods struggle to produce containers with sharp edges that are dimensionally accurate and reproducible, as the material thinning and cooling issues lead to inconsistent edge radii and weakened container walls.

Innovation Solution

A multi-part blow mold with movable regions allows for the compression of the container during the blowing process, enabling the formation of sharp edges by counteracting material thinning and ensuring precise edge formation between the container body, shoulder, and bottom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional blow-molding methods are used to produce containers with sharp edges, then the desired edge sharpness is achieved, but the material thinning and cooling issues lead to inconsistent edge radii and weakened container walls

Engineering Contradiction:

Improveedge sharpnessVSAvoiddimensional accuracy and consistency of edge radius

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The blow mold is divided into multiple independent parts (first mold part, second mold part, and at least one additional mold part) that can move relative to each other. This segmentation allows different regions of the mold to perform different functions: some regions maintain the container in inflated state while others compress specific areas to form sharp edges, thereby achieving both edge sharpness and dimensional consistency without material thinning

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mold parts are designed to be movable rather than fixed, allowing dynamic adjustment during the blow-molding process. The at least one additional mold part can move relative to the first and second mold parts to apply compression forces at specific stages, enabling precise control over edge formation while maintaining overall container dimensions and preventing material thinning

Inventive Principle:

Principle #15Dynamics

2Shape

If the container is compressed to form sharp edges during blowing, then edge sharpness is improved, but the material thinning weakens the container walls

Engineering Contradiction:

Improveedge sharpnessVSAvoidcontainer wall strength

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The compression action for forming sharp edges is performed at a predetermined stage during the blow-molding process, after the container has been sufficiently inflated but while the material is still warm and formable. This timing allows edge compression without excessive material thinning, as the container wall has already gained sufficient strength from the inflation process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The compression force is applied locally at specific regions where sharp edges are desired, rather than compressing the entire container uniformly. The at least one additional mold part is positioned to compress only the specific areas needing sharp edges, leaving other regions of the container wall sufficiently thick and strong

Inventive Principle:

Principle #3Local quality

3Shape

If the blow mold uses fixed mold parts, then the device complexity is low, but the ability to form sharp edges with dimensional accuracy is limited

Engineering Contradiction:

Improveedge sharpness with dimensional accuracyVSAvoidblow mold structure complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The blow mold is divided into multiple independent parts (first mold part, second mold part, and at least one additional mold part) that can move relative to each other. This segmentation allows different regions of the mold to perform different functions: some regions maintain the container in inflated state while others compress specific areas to form sharp edges, thereby achieving both edge sharpness and dimensional consistency without material thinning

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mold parts are designed to be movable rather than fixed, allowing dynamic adjustment during the blow-molding process. The at least one additional mold part can move relative to the first and second mold parts to apply compression forces at specific stages, enabling precise control over edge formation while maintaining overall container dimensions and preventing material thinning

Inventive Principle:

Principle #15Dynamics

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 allows for the reliable production of containers with sharp edges that are dimensionally accurate and reproducible, enhancing stackability and visual appeal while maintaining the structural integrity of the container.

Implementation Method 1

introducing a preform into a cavity of a blow mold, inflating the preform to form a container

Methodology Applied

Scientific EffectInflation: Pressure Increase

Implementation Method 2

relative movement of the center region to the top region and/or to the bottom region, such that the container is compressed at least in a region for forming the edge

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS12275181B2Blow mold, stretch blow molder and method for forming a container

Publication Date: 2025.04.15 ALPLA WERKE ALWIN LEHNER

AI summary

The invention relates to a blow mold (100) comprising a mold base (101) having a cavity (102) as the mold cavity, the cavity (102) having a bottom region (1), a center region (2) and a top region (3). When the blow mold (100) is closed, the center region (2) can be moved relative to the top region (1) and/or relative to the bottom region (3).