Single-Step Plastic Container Forming Using Incompressible Fluid

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing blow molding process for plastic containers is energy-intensive due to pre-heating requirements, lacks control over the molding process, and results in amorphous containers with suboptimal crystallinity and mechanical properties, as it relies on compressible gases and maintains high temperatures above the vitreous transition point.

Innovation Solution

The process uses an incompressible fluid, such as water, at ambient temperature to expand preforms below their vitreous transition temperature, allowing sequential or simultaneous stretching and injection, which reduces energy consumption, enhances process control, and increases crystallinity by facilitating crystallization during molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If preheating is used to maintain plastic at proper temperature for forming, then the preform becomes soft and pliable for molding, but energy costs increase significantly

Engineering Contradiction:

Improvepreform temperatureVSAvoidenergy cost

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter from above vitreous transition (conventional) to below vitreous transition (novel), allowing molding at lower temperatures and reducing energy consumption while achieving the desired material flow through controlled deformation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary stretching of the preform before molding, creating deformation zones that facilitate material flow during subsequent molding at lower temperatures, eliminating the need for extensive preheating

Inventive Principle:

Principle #10Preliminary action

2Shape

If compressible gas is used for blowing into the preform, then the preform expands to fill the mold cavity, but control over the molding process is diminished

Engineering Contradiction:

Improvecontainer shapeVSAvoidprocess control

Core Design Contradiction:

ShapeVSEase of operation

Solution Approach 1:

The invention transitions from using compressible gas (pneumatics) to using incompressible liquid (hydraulics) for the blowing process, providing superior control over the molding process while achieving the desired container shape through controlled fluid pressure

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Manufacturing precision

If the preform is cooled after molding, then the container can be removed from the mold, but the cycle time increases and process complexity increases

Engineering Contradiction:

Improvecontainer dimensional stabilityVSAvoidcycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention performs preliminary stretching and deformation of the preform before the molding step, pre-establishing the material flow patterns that reduce the need for post-molding cooling and dimensional stabilization, thereby reducing cycle time

Inventive Principle:

Principle #10Preliminary action

4Ease of manufacture

If the preform is molded above the vitreous transition point, then the plastic remains soft for forming, but the molecular structure remains amorphous with reduced strength

Engineering Contradiction:

ImproveformabilityVSAvoidcontainer strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the temperature parameter from above to below the vitreous transition point, and introduces controlled stretching to induce crystallization, achieving both adequate formability and enhanced strength through crystalline structure formation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary stretching to induce molecular orientation and crystallization before the molding step, ensuring that the material develops strength through crystalline structure formation while maintaining the ability to be formed into the desired shape

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 significantly reduces energy costs, improves control over the molding process, and enhances the mechanical and chemical properties of the containers by increasing crystallinity, leading to faster cycle times and cost savings while maintaining product quality.

Implementation Method 1

an incompressible fluid under pressure is injected into the preform, causing the preform to expand and fill the mold cavity

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

increases the crystallinity of the container by inducing crystallization during the stretching process

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS10189586B2Process for single-step forming and filling of containers

Publication Date: 2019.01.29 DISCMA AG

AI summary

A process for the manufacturing and filling of plastic containers, the process comprising the steps of:positioning a preform with relation to a mold assembly of two or more components, the preform generally being fabricated from a plastic and being provided with a longitudinal axis and presenting a stretchable portion and a non-stretchable portion;stretching the preform along its longitudinal axis;injecting a fluid into the interior volume of the preform, the fluid being under such pressure as to cause the preform to plastically deform until achieving the desired size and shape; andreleasing the container from the mold assembly and sealing the container, and in which at least a portion of the stretchable portion of the perform is at a temperature below its vitreous transition temperature (Tg) and, preferably, at ambient temperatures.