Compression Chambers in Powder AM for Stress Relief and Powder Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Additive manufacturing techniques face issues with thermal contraction causing objects to crack or develop structural weaknesses due to retained powder, and the powder becoming difficult to remove during post-processing operations.
Innovation Solution
The method involves forming compression chambers within the object that enclose unfused powder, connected to tubes and passages, allowing for selective removal of powder via valves and vacuum, and using a rod to relieve pressure on impacted powder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If compression chambers are grown to enclose unfused powder, then powder removal is facilitated, but device complexity increases due to additional tubes and passages
Solution Approach 1:
The build chamber is segmented into multiple compression chambers, each enclosing unfused powder in separate regions. This allows independent removal of powder from different areas through dedicated tubes and passages, facilitating easier powder removal while managing the complexity through modular organization
Solution Approach 2:
Tubes are grown within the compression chambers, and passages are formed within the build platform to connect to these tubes. This nested structure allows the removal system to be integrated within the existing chamber geometry, facilitating powder removal without proportionally increasing overall device complexity
2Reliability
If thermal contraction is managed through compression chambers, then structural weaknesses and cracking are reduced, but manufacturing precision requirements increase
Solution Approach 1:
Compression chambers are grown during the additive manufacturing process before final cooling and contraction occurs. This preliminary formation of chambers with tubes and passages allows the structure to accommodate subsequent thermal contraction, reducing structural weaknesses and cracking while maintaining manageable precision requirements
Solution Approach 2:
The system manages thermal contraction by changing the physical state and pressure parameters within the compression chambers. By controlling the enclosed unfused powder and applying compression, the structure accommodates thermal contraction, improving reliability without requiring extreme manufacturing precision
3Strength
If unfused powder is retained in compression chambers, then compression can be applied to relieve loading, but powder becomes difficult to remove during post-processing
Solution Approach 1:
Tubes are grown extending from the compression chambers to the exterior of the built object, and passages are formed in the build platform to connect to these tubes. This extraction pathway allows unfused powder to be removed from the compression chambers after compression is applied, resolving the difficulty of powder removal while maintaining the strength benefits of compression
Solution Approach 2:
The system transitions from a static retained powder state to a dynamic removal process. Tubes and passages enable the powder to be extracted on demand after compression, allowing the system to adapt between maintaining compression for strength and removing powder for ease of operation
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 mitigates structural weaknesses by managing thermal contraction and facilitates easier powder removal, reducing the risk of cracking and improving post-processing efficiency.
Implementation Method 1
uses an energy beam, for example, an electron beam or electromagnetic radiation such as a laser beam, to sinter or melt a powder material
Implementation Method 2
The physical processes associated with laser sintering or laser melting include heat transfer to a powder material
Implementation Method 3
The compression chambers may be emptied by, for example, applying a vacuum
Implementation Method 4
the compression chambers may be selectively emptied in order to reduce pressure within the object. The compression chambers may then be compressed by pressure from external powder
Implementation Method 5
As the objects cool, thermal contraction may cause the object to compress the retained powder
Data Source
AI summary
The present disclosure generally relates to methods and apparatuses for additive manufacturing (AM) that utilize compression chambers to reduce pressure on grown objects. In one aspect, the disclosure provides a method for fabricating an object. The method includes (a) irradiating a layer of powder in a build area above a build platform to form a fused region; (b) providing a subsequent layer of powder over the build area; and (c) repeating steps (a) and (b) until at least a portion of the object, at least one chamber, and a tube are formed in the build area. The chamber encloses a region of unfused powder and the tube extends from a passage within the build platform to the chamber. The method also includes (d) removing unfused powder from within the chamber via the tube and the passage. The disclosure also provides an apparatus for forming compression chambers within an object.