Three-Dimensional Object Production With Constant-Pressure Gas Filtration

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Solution Overview

Problem

Existing devices for manufacturing three-dimensional objects by layer-by-layer application and selective solidification of build material face issues with pressure changes due to filter system contamination, leading to component deformation and dimensional inaccuracies.

Innovation Solution

A device and method that maintain a constant pressure in the process chamber using a recirculating air filter system with a pressure control device, including gas supply and outlet adjustment, and a gas flow control mechanism to stabilize the pressure during filter cleaning, ensuring precise vertical positioning and layer thickness control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a recirculating air filter system is used to clean substances from the gas, then the gas is purified and contaminants are removed, but the flow resistance increases and pressure changes occur in the process chamber

Engineering Contradiction:
Improvecontaminant removalVSAvoiddimensional accuracy
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

A pressure sensor continuously monitors the pressure in the process chamber and provides feedback to the control unit. When pressure deviations are detected (caused by filter contamination), the control unit automatically adjusts the gas supply valve to regulate the protective gas flow rate, compensating for the increased flow resistance and maintaining constant pressure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the protective gas flow rate parameter in response to filter contamination. As the filter becomes clogged and flow resistance increases, the control unit increases the protective gas flow rate to compensate, thereby maintaining constant pressure in the process chamber despite the deteriorating filter condition.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the filter element is cleaned by a pressure pulse, then the flow resistance decreases and filtering efficiency is restored, but abrupt pressure changes occur in the process chamber

Engineering Contradiction:
Improvefilter cleaning efficiencyVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Before initiating the pressure pulse cleaning of the filter element, the control unit preemptively reduces the protective gas flow rate through the gas supply valve. This preliminary action creates a buffer that prevents the pressure pulse from causing abrupt pressure changes in the process chamber, thereby maintaining dimensional accuracy during filter cleaning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system cushions against potential pressure spikes during filter cleaning by pre-adjusting the protective gas flow rate downward. This beforehand cushioning ensures that when the pressure pulse is applied to clean the filter, the overall pressure in the process chamber remains stable, preventing component deformation and maintaining manufacturing precision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If the protective gas flow rate is increased to compensate for filter contamination, then the pressure is maintained, but more gas is consumed

Engineering Contradiction:
Improvepressure stabilityVSAvoidgas consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The pressure sensor provides continuous feedback on the actual pressure in the process chamber. The control unit uses this feedback to precisely modulate the protective gas flow rate, increasing it only to the extent necessary to compensate for filter contamination and maintain pressure stability, thereby avoiding excessive gas consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The protective gas flow rate is made dynamic rather than static. The control unit continuously adjusts the flow rate based on real-time pressure conditions and filter contamination levels, optimizing the balance between maintaining pressure stability and minimizing gas consumption by applying only the necessary compensation.

Inventive Principle:
Principle #15Dynamics

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 enhances the dimensional accuracy of the manufactured object by preventing pressure fluctuations, allowing for precise control of layer thickness and vertical positioning, thereby improving the precision and integrity of the manufacturing process.

Implementation Method 1

a recirculating air filter device (32) for removing substances from the gas

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

pressure control device designed to maintain the pressure, i.e. a desired (process chamber) operating pressure, in the process chamber at a substantially constant level

Methodology Applied
Scientific EffectPressure control through flow regulation:

Implementation Method 3

gas flow control mechanism to stabilize the pressure during filter cleaning

Methodology Applied
Scientific EffectFlow control:

Data Source

PatentEP3393807B2Device and method for producing a three-dimensional object
Publication Date: 2025.11.05 EOS GMBH ELECTRO OPTICAL SYST
  • EP3393807B2 patent drawingFigure 1
  • EP3393807B2 patent drawingFigure 2
  • EP3393807B2 patent drawingFigure 3

AI summary

The invention relates to a device (1) for producing a three-dimensional object (2) by solidifying construction material (15) layer by layer at locations in the respective layer, which correspond to the cross-section of the object (2) to be produced, comprising a process chamber (3), in which the object (2) is to be constructed layer by layer by selectively solidifying layers of a construction material (15) in a construction field (8), a gas supply device (100) and a circulating air filter device (32), wherein the device (1) comprises a device for maintaining a pressure constant, which is designed to maintain the pressure in the process chamber (3) substantially constant.