Additive Manufacturing Compression Roller Cooling

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Solution Overview

Problem

Existing 3D printing systems face challenges in maintaining a freewheeling compression roller with minimal rotational friction and effective cooling, particularly when processing high-temperature polymers like polyphenylene sulfide, which can lead to polymer adhesion and print defects.

Innovation Solution

A system utilizing a cooled liquid coolant routed through a rotary union and a tubular compression roller with low friction bearings, allowing the roller to rotate freely while being cooled below the polymer's melting temperature, thereby preventing adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the compression roller is cooled to prevent polymer adhesion, then polymer adhesion is prevented, but rotational friction increases

Engineering Contradiction:
Improvepolymer adhesionVSAvoidrotational friction
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

A coolant fluid serves as an intermediary substance, flowing through channels in the roller to transfer heat away from the compression roller surface. This mediator enables cooling without direct thermal contact that would cause adhesion, while the roller surface remains free to rotate with minimal friction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a hydraulic cooling system where coolant fluid is pumped through internal channels of the compression roller. This hydraulic approach efficiently removes heat from the roller to prevent polymer adhesion while maintaining the roller's mechanical properties for low-friction rotation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Force

If the compression roller is made to rotate freely to reduce friction, then rotational friction is minimized, but cooling effectiveness decreases

Engineering Contradiction:
Improverotational frictionVSAvoidroller temperature
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The compression roller is segmented into functional zones with internal coolant channels distributed throughout its structure. This segmentation allows cooling to occur at multiple points simultaneously, maintaining effective temperature control while the external surface rotates freely with minimal friction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling function is moved from the external surface to the internal structure of the roller through embedded coolant channels. This dimensional transition allows the external surface to rotate freely for low friction while the internal channels provide continuous cooling.

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

3Strength

If a solid compression roller is used to maintain structural integrity, then structural strength is maintained, but cooling efficiency is reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidcooling efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The compression roller incorporates thin-walled internal channels formed within its structure. These thin film-like channels provide extensive surface area for heat transfer while maintaining the overall structural integrity and strength of the roller through optimized wall thickness and channel distribution.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The roller structure incorporates a network of internal channels that create a porous-like flow path for the coolant. This channelled structure increases the surface area available for heat transfer while maintaining the structural strength needed for compression operations.

Inventive Principle:
Principle #31Porous materials

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 solution ensures the compression roller operates with minimal friction and maintains a temperature below the polymer's melting point, preventing adhesion and ensuring defect-free printing of high-temperature polymers.

Implementation Method 1

a coolant circuit operable to cool the compression roller

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

The compression roller may include a coolant circuit and low friction bearings

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Data Source

PatentEP3706979B1Improved compression roller design and method for additive manufacturing
Publication Date: 2021.11.03 THERMWOOD CORP
  • EP3706979B1 patent drawingFigure 1
  • EP3706979B1 patent drawingFigure 2
  • EP3706979B1 patent drawingFigure 3

AI summary

An additive manufacturing system (1) may include a nozzle (51) having an inlet for receiving a flowable material (53) and an outlet for depositing the flowable material. The system also may include an applicator head (43) surrounding at least a portion of the nozzle. Additionally, a roller (59) may be mounted on the applicator head and rotatable about an axle (73). A coolant circuit may extend through at least a portion of the applicator head and through a lumen of the axle.