3D Printed Cavity Warpage Control via Intermediary Support

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Solution Overview

Problem

Three-dimensional printed articles with inwardly extending cavities often experience warpage during heat treatment due to their weak structural features, which can render the binder jet printing process unsuitable for producing such articles.

Innovation Solution

A method involving 3DP BJ printing an insertable object from the same build powder as the article, which is contactingly inserted into the cavity to provide structural support and coated to prevent bonding, along with a flowable powder bed for support during heat treatment, ensuring the insertable object and article transform similarly and can be removed without bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If 3DP BJ printing is used to make articles with cavities, then economic efficiency is improved, but warpage occurs during heat treatment due to weak structural features

Engineering Contradiction:
Improveeconomic efficiencyVSAvoidgeometrical distortion
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A support object made from the same build powder is inserted into the cavity to act as an intermediary structural element. This support object provides internal reinforcement to the thin-walled cavity structures during heat treatment, preventing warpage while allowing the economical 3DP BJ process to be used for producing complex cavitied articles

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If an insertable object is placed in the cavity for support, then warpage is prevented, but bonding between the insertable object and article occurs during heat treatment

Engineering Contradiction:
Improvegeometrical distortionVSAvoidbonding
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The support object is extracted or removed from the cavity after heat treatment completes. This allows the support object to perform its warpage-prevention function during processing, then be discarded since it served only as a temporary support structure and no longer serves a functional purpose in the final article

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of repair

If the insertable object is removed after heat treatment, then the support function is no longer needed, but removal difficulty increases if bonding occurs

Engineering Contradiction:
ImproveremovalVSAvoidbonding
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

A release agent or coating is applied to the support object or cavity surfaces as an intermediary layer. This coating prevents direct bonding between the support object and article during heat treatment, ensuring the support object can be easily removed after processing while maintaining its warpage-prevention function during the heat treatment process

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method effectively prevents warpage by providing structural support that mimics the shrinkage of the article's surfaces, allowing for successful transformation and removal without bonding issues, thus enabling the production of articles with inwardly extending cavities.

Implementation Method 1

supporting the 3DP BJ article during the heat treatment in the powder bed

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the 3DP BJ article and the 3DP BJ object are heat treated. The heat treatment transforms the 3DP BJ article into the intended article itself

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

heat treated to transform the 3DP BJ article into the intended article itself. This transformation is accompanied by a marked increase in strength

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3206861B1Methods for controlling warpage of cavities of three-dimensionally printed articles during heat treatment
Publication Date: 2024.08.07 THE EX ONE
  • EP3206861B1 patent drawingFigure 1~2
  • EP3206861B1 patent drawingFigure 3~4
  • EP3206861B1 patent drawingFigure 5~6

AI summary

Methods are presented for controlling warpage during heat treatment of a 3DPBJ article having a cavity extending inwardly from an outside surface wherein a 3DPBJ article is 3DPBJ printed from a build powder as is a 3DPBJ object which is adapted to be contactingly insertable into the cavity of the 3DP BJ article. At least a portion of the 3DPBJ article cavity surface and/or at least a portion of the surface of the 3DPBJ object is treated to prevent the 3DPBJ object from becoming bonded to the 3DPBJ article during the heat treatment. The 3DPBJ object is inserted into the 3DPBJ article cavity and the 3DPBJ article and the 3DPBJ object are heat treated to transform the 3DPBJ article into the intended article itself and the 3DPBJ object into a heat treated 3DPBJ object. The heat treated 3DPBJ object is removed from the article.