Independent Motorization for Stretch-Blowing Mold Synchronization

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Solution Overview

Problem

Conventional blowing and stretch-blowing machines for plastic preforms are complex, require frequent maintenance, and lack flexibility in mold opening and closing mechanisms, necessitating the replacement of cam systems for different shapes and sizes.

Innovation Solution

A rotating blowing or stretch-blowing machine with independently motorized half-molds and a bottom plate, utilizing actuators like stepper or brushless motors, eliminates mechanical cams and allows for customizable mold opening and closing through interchangeable shaped portions and removable abutment profiles, enabling flexible production without the need for complex mechanical transmission systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cam systems are used for mold opening and closing, then the machine can operate with synchronized mold movement, but the device complexity increases and maintenance frequency increases

Engineering Contradiction:
Improvemold synchronizationVSAvoidcam system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical cam system with an independent motorization system using electric motors (such as stepper motors or brushless motors) to directly drive the mold half-molds for opening and closing. This substitution eliminates the complex mechanical transmission elements including cams, leverages, and mechanical linkages, thereby reducing device complexity while maintaining synchronized mold movement through electronic control

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

Solution Approach 2:

The patent extracts and removes the cam system from the mold opening and closing mechanism, separating the mold actuation function from the rotational motion transmission. By taking out the cam system entirely and using independently motorized half-molds, the patent simplifies the overall machine structure while maintaining the necessary synchronized operation of molds

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If cam systems are used for different bottle shapes and sizes, then the machine can produce various containers, but the ease of manufacture decreases due to frequent cam replacements

Engineering Contradiction:
Improvebottle shape and size variationVSAvoidcam system modification
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements a dynamic and adjustable mold system where the half-molds can be independently positioned and controlled by motors. This allows the mold geometry to be dynamically adjusted for different bottle shapes and sizes through programmable motor control rather than requiring physical replacement of mechanical components. The system adapts to different production requirements by changing control parameters rather than mechanical parts

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The independently motorized half-mold system serves multiple functions: it can produce various bottle shapes and sizes, control opening and closing speeds independently, and adjust positioning precision. This universal system replaces the need for multiple specialized cam systems, making the machine versatile for different container types while maintaining ease of manufacture through software configuration rather than mechanical modification

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If complex mechanical transmission systems are used, then the molds can be opened and closed in synchronized manner, but the productivity decreases due to frequent maintenance

Engineering Contradiction:
Improvemold operation stabilityVSAvoidmachine downtime
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical transmission systems with direct electric motor actuation of the mold half-molds. This eliminates mechanical wear elements such as cam surfaces, bearings, and linkages that require frequent maintenance. The electronic control system maintains reliable synchronized operation without the degradation issues inherent in mechanical systems, thereby reducing maintenance downtime and increasing productivity

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

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 design simplifies the machine construction, reduces maintenance, and enhances flexibility by allowing for various bottle shapes and sizes without replacing mechanical parts, reducing vibrations, noise, and wear, while optimizing processing times and increasing productivity.

Implementation Method 1

Each mold comprises an actuator which drives a single synchronized actuation opening/closing mechanism of the half-molds and of the bottom plate

Methodology Applied
Scientific EffectStepper motor or brushless motor actuation: Linear Motor

Implementation Method 2

the preforms must reach the blowing or stretch-blowing machine in a thermal condition which corresponds to the softening point of the material, so as to be able to be plastically deformed inside the molds

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

There are substantially two different techniques, simple blowing and stretch-blowing, which include pneumatic blowing and the concurrent mechanical stretching of the preform in the mold

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Increase

Data Source

PatentEP3103615B1Blowing or stretch-blowing machine for bottles made of polymer material
Publication Date: 2020.10.07 SMI SPA
  • EP3103615B1 patent drawingFigure 1A~1B
  • EP3103615B1 patent drawingFigure 2A~2B
  • EP3103615B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a blowing or stretch-blowing machine for preforms made of polymer material adapted to transform said preforms into bottles or containers, and in particular to the closing mechanism of the forming half-molds. The invention machine (1) having a plurality of molds (1) movable on a transport system, in which each of said molds (1) comprises a first half-mold (2a) and a second half-mold (2b) hinged around a hinge axis (3) and a bottom plate (4), and means for vertical/translational movement of the bottom plate, to cyclically form a closed cavity adapted to receive a preheated preform whereby each of said molds (1) comprises a system for synchronized opening/closing of the half-molds (2a, 2b) and of the bottom plate (4) actuated by an actuator thereof (30) independent from the motorization of the machine.