Extrusion Molding System with Dynamic Ram Control

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Solution Overview

Problem

Conventional extrusion molding processes face challenges in maintaining consistent product quality, energy efficiency, and cost-effectiveness due to varying melt pressures and material properties, leading to issues like sink marks, warping, and uneven material composition.

Innovation Solution

A method of extrusion molding at low, substantially constant melt pressures, utilizing a novel hot runner system with a cold runner portion that is reheated conductively between molding cycles, and optimized breaker plates for improved pressure control and material mixing, enabling better temperature control and homogeneity in the extruded profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional extrusion molding processes are used, then production can proceed with standard equipment, but melt pressure varies leading to inconsistent product quality, sink marks, and warping

Engineering Contradiction:

Improveproduct quality consistencyVSAvoidmelt pressure variation

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

The system dynamically adjusts the ram speed during the extrusion process based on real-time melt pressure feedback. When pressure deviates from the target range, the ram speed is automatically modified to bring pressure back within specifications, ensuring consistent product quality while maintaining flexible production

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A melt pressure sensor continuously monitors the extrusion process and feeds this information back to the control system. The controller compares actual pressure against target pressure and adjusts ram speed accordingly, creating a closed-loop control system that eliminates pressure variation and prevents defects like sink marks and warping

Inventive Principle:

Principle #23Feedback

2Productivity

If higher melt pressure is used to fill the mold cavity, then filling speed increases, but energy consumption increases and material homogeneity decreases

Engineering Contradiction:

Improvemold filling speedVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Instead of using constantly high pressure, the system dynamically adjusts ram speed to maintain optimal melt pressure throughout the filling process. This dynamic control achieves complete mold filling at lower average pressure levels, reducing energy consumption while maintaining productivity through optimized filling profiles

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the pressure parameter dynamically during the extrusion cycle rather than maintaining constant high pressure. By adjusting ram speed to keep melt pressure within a specific range, the process achieves efficient filling with reduced energy input and improved material homogeneity

Inventive Principle:

Principle #35Parameter changes

3Temperature

If conventional heating methods are used for the runner system, then continuous heating is maintained, but energy consumption increases and heating time extends

Engineering Contradiction:

Improverunner system temperatureVSAvoidheating energy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The runner system uses periodic conductive heating between molding cycles instead of continuous heating. The heating elements are activated only when needed to restore runner temperature, significantly reducing energy consumption while maintaining proper temperature levels for the next injection cycle

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system leverages the residual heat in the runner system and the heat generated by the incoming molten plastic to maintain temperature during idle periods. Conductive heating elements provide supplemental heat only when temperature drops below the required threshold, creating an energy-efficient self-regulating thermal system

Inventive Principle:

Principle #25Self-service

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 results in a more consistent, energy-efficient, and cost-effective extrusion process with reduced sink marks, improved material homogeneity, and enhanced temperature control, allowing for the production of straighter and more uniform extruded profiles.

Implementation Method 1

a novel hot runner system with a cold runner portion that is reheated conductively between molding cycles

Methodology Applied

Scientific EffectConductive heating: Conduction (thermal)

Implementation Method 2

optimized breaker plates for improved pressure control and material mixing

Methodology Applied

Scientific EffectPressure control through restricted flow: Pressure Drop

Implementation Method 3

The material is gradually melted by the mechanical energy generated by turning screws and by heaters arranged along the barrel

Methodology Applied

Scientific EffectMechanical energy conversion to heat: Viscous Heating

Data Source

PatentUS20220250300A1Low-Pressure Molding System

Publication Date: 2022.08.11 GRAM

AI summary

The present invention relates to extrusion molding machines and methods of producing extrusion molded parts and, more particularly, to extrusion molding machines that adjust operating parameters of the extrusion molding machine during an extrusion molding run to account for changes in material properties and pressures of the extrusion material and methods of accounting for changes in extrusion molding material properties during an extrusion molding run and/or compounding of materials.