Extrusion Closure Piston for Discontinuous Material Flow Control

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Solution Overview

Problem

Extrusion-based processes in additive manufacturing lack the ability to control and regulate the volume flow of extruded materials, leading to insufficient component accuracy, excess material application, and damage to component structures due to their continuous nature, which limits the usability of these processes.

Innovation Solution

A control and closure device featuring a flange with a channel and movable pistons that allow for translational and rotational movement, enabling the regulation of the volume flow by changing the cross-sectional area and redirecting material to a bypass nozzle, allowing for discontinuous discharge and pressure management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a continuous extrusion process is used, then high discharge rates are achieved, but the volume flow cannot be regulated leading to insufficient component accuracy

Engineering Contradiction:
Improvedischarge rateVSAvoidcomponent accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies the dynamics principle by making the piston movable within the channel to dynamically adjust the cross-sectional area for material flow. This allows the system to transition from a static continuous extrusion process to a dynamic one where the volume flow can be regulated in real-time, resolving the contradiction between maintaining high discharge rates and achieving regulatable volume flow for component accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the flow channel by moving the piston to alter the cross-sectional area. This parameter change enables continuous adjustment of the volume flow rate while maintaining the high discharge capability of the extrusion process, thus resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the extrusion screw rotation is interrupted to regulate material volume flow, then volume control is achieved, but overfilling and dimensional deviations occur

Engineering Contradiction:
Improvematerial volume flowVSAvoiddimensional accuracy
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The piston acts as an intermediary element between the continuous extrusion screw and the outlet nozzle. Instead of interrupting the screw rotation, the piston mediates the material flow by adjusting its position to control the cross-sectional area, allowing continuous extrusion while achieving precise volume control without overfilling or dimensional deviations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The movable piston provides dynamic control of material volume flow without requiring interruption of the extrusion process. By continuously adjusting the piston position, the system can regulate the amount of material discharged while maintaining dimensional accuracy, eliminating the problems of overfilling associated with rotational interruption methods.

Inventive Principle:
Principle #15Dynamics

3Productivity

If no volume flow regulation is implemented, then the continuous extrusion process operates smoothly, but excess material is applied and component structure is damaged

Engineering Contradiction:
Improvecontinuous process operationVSAvoidexcess material and structural damage
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The piston introduces local quality control within the channel by creating a variable restriction point. This local adjustment mechanism allows the system to maintain smooth continuous operation overall while locally controlling the material flow rate to prevent excess material application and the resulting structural damage to components.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3853000B1Control and closure device for extruded plastically deformable material
Publication Date: 2022.11.09 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3853000B1 patent drawingFigure 1
  • EP3853000B1 patent drawingFigure 2

AI summary

In the control and closure device, a duct (7) through which material (5) can be conveyed to the outlet nozzle is routed through the flange (1). Two pistons (2) are guided into the duct on two opposite sides. At least one piston (2, 3) is mounted and guided in a translationally movable and/or rotatable manner. In one of the pistons (2, 3) there is formed an opening which opens into a duct (6) which is routed through said piston (2, 3) and which in turn opens into a bypass nozzle (4). On the outer lateral surface of the at least one piston (2, 3) there is formed a groove (8) through which material can be conveyed in the direction of the outlet nozzle. The piston (2, 3) can be rotated in such a way that there is a connection to the outlet nozzle. The free cross section is changed during a translational and/or rotational movement of the piston (2, 3). A piston (2, 3) can be rotated in such a way that control of the volumetric flow of the material (5) passing through the duct (7) can be achieved. Upon closure of the duct (7), the opening can be positioned such that material (5) can be conveyed.