Channeled Support Layer for Powder Removal in Selective Sintering
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Solution Overview
Problem
Current 3D printing methods using laser or electron beam sintering/melting of powdered materials face challenges in building free-standing parts without support structures, as they induce thermal stresses, require complex scaffolding, and leave voids with unmelted powder, which complicates subsequent processing and is hazardous.
Innovation Solution
A method involving an intermediate grooved or channeled solid layer is built between the platen and the part using laser sintering/melting, allowing loose powder removal before further processing, with channels aligned to the recoater blade for efficient powder extraction and providing mechanical stability during building and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If support structures are used to enable free-standing part building, then mechanical stability is improved, but device complexity and processing time increase
Solution Approach 1:
The support structure is segmented into a solid base layer with integrated channels for powder removal, rather than using complex hollow shells or cross-hatched structures. This segmentation allows the support to provide mechanical stability while simplifying the overall design and reducing processing time.
Solution Approach 2:
The harmful element (loose powder) is extracted from the support structure through integrated channels that open to the exterior. This allows powder to be removed during or after the printing process, eliminating the need for complex hollow structures while maintaining mechanical stability.
2Loss of substance
If hollow shell or cross-hatched support structures are used, then powder removal is facilitated, but mechanical strength and stability deteriorate
Solution Approach 1:
The solid support layer serves multiple functions simultaneously: it provides mechanical stability during printing, contains integrated channels for powder removal, and acts as a base for the printed part. This multi-functionality eliminates the need to compromise between strength and powder removal capability.
Solution Approach 2:
The channels act as intermediaries that connect the interior of the support structure to the exterior, allowing powder to be removed through the solid support layer without compromising its mechanical integrity. The channels mediate between the conflicting requirements of strength and powder removal.
3Strength
If solid support structures are used, then mechanical stability is improved, but powder removal becomes difficult and processing time increases
Solution Approach 1:
The channels for powder removal are built into the support structure during the printing process itself, rather than requiring separate post-processing steps. This preliminary action eliminates additional processing time while maintaining the mechanical strength of the solid support structure.
4Loss of substance
If channels are added to the support structure for powder removal, then powder extraction is improved, but manufacturing complexity increases
Solution Approach 1:
The channel formation process is merged with the support structure printing process. The channels are created as integral parts of the support layer during the same printing operations, eliminating the need for separate fabrication steps and reducing manufacturing complexity.
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 effectively removes trapped powder, prevents delamination, and allows for reliable production of complex shapes, including thin pillars, while being compatible with existing laser sintering/melting processes, reducing processing costs and hazards.
Implementation Method 1
direct a CO2 or fibre laser onto a layer of powder... the heat from the thermal source melts or sinters the powder layer by layer
Implementation Method 2
commercial powder bed 'Selective Laser Sintering'/'Selective Laser Melting' (SLS/SLM) machines... take metal powders under an inert atmosphere and direct a CO2 or fibre laser onto a layer of powder
Implementation Method 3
the heat from the thermal source melts or sinters the powder layer by layer to form a solid
Implementation Method 4
other similar powder bed machines sometimes using an electron beam
Implementation Method 5
commercial powder bed 'Selective Laser Sintering'/'Selective Laser Melting' (SLS/SLM) machines
Implementation Method 6
forming layers of powder using a powder recoater blade which traverses the platen
Implementation Method 7
enabling substantially all trapped loose powder to be removed by e.g. gravity, tapping, vacuum or blowing
Implementation Method 8
a point source of energy such as a laser or electron beam is selectively applied to a layer of powder and in related processes a powder/thermal source is directed as required on a layer by layer basis to build up a 3D part... the heat from the thermal source melts or sinters the powder layer by layer to form a solid
Data Source
AI summary
From one aspect, a method of forming a support for use in a selective sintering or melting process includes forming a body on a platen having a plurality of generally parallel channels each channel being open at least one end. The base of the channels may be formed by the platen. Preferably the support is formed by a selective sintering or melting process.