STEP Additive Manufacturing Surface Finish via Gap Filling
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Solution Overview
Problem
Existing additive manufacturing techniques, such as selective toner electrophotographic process (STEP), struggle to achieve smooth surface finishes, particularly on surfaces with a significant Z-axis component, which are often formed in conjunction with support material.
Innovation Solution
The method involves forming a gap between adjacent layers of part material and support material, and then applying pressure and heat to transfer some of the material into the gap, creating enhancement layers that increase the material adjacent to the gap. This pressure and heat application cause the material to flow horizontally and upward, filling the gap and smoothing the interface between part and support materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If support material is used to form overhanging portions and cavities in STEP additive manufacturing, then the structural integrity and buildability of complex geometries is improved, but the surface finish quality deteriorates due to visible interfaces and roughness at support material junctions
Solution Approach 1:
The invention extracts and removes the support material after the additive manufacturing process is complete. By designing the support material as temporary sacrificial material that can be cleanly removed, the patent resolves the contradiction by allowing support material to enable complex geometries during printing, then eliminating it to reveal smooth surfaces without support material junctions visible on the final part.
Solution Approach 2:
The invention applies different material properties and processing conditions to different regions of the build. The support material is formulated with specific characteristics that allow it to be easily removed from certain regions while leaving the part material intact. This local differentiation enables the support material to serve its structural function during printing while allowing for clean removal to achieve smooth surface finishes on the final part.
2Productivity
If layers of part material and support material are deposited adjacent to each other in a common X-Y plane, then the productivity and build speed are improved, but the surface roughness increases at the interface between part and support material
Solution Approach 1:
The invention performs preliminary actions during the layer deposition process by carefully controlling the interface between part and support material layers. The support material is deposited in a controlled manner that anticipates its future removal, creating a configuration that enables both high build speed during printing and smooth surface finishes after support removal. This preliminary structuring resolves the contradiction between productivity and surface quality.
Solution Approach 2:
The invention employs discarding of the support material after it has served its purpose during the additive manufacturing process. The support material is intentionally designed to be temporary and removable, allowing high-speed co-deposition of part and support material during printing, then enabling clean removal to achieve smooth surfaces. This discarding strategy resolves the surface roughness issue while maintaining build speed.
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
The approach results in improved surface properties, including reduced roughness, by smoothing the interface between part and support materials, leading to a smoother finished part surface.
Implementation Method 1
application of heat and pressure to the part material and support material such that a portion of the part material and support material flows into and at least partially fills the gap
Implementation Method 2
application of heat and pressure to the part material and support material such that a portion of the part material and support material flows into and at least partially fills the gap
Data Source
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AI summary
Embodiments herein relate to 3D printing. In an embodiment, a method for printing an article using a selective toner electrophotographic process ("STEP") includes successively depositing multiple layers of part material and support material, the layers deposited substantially parallel to a first plane; wherein: a) the multiple layers of part material and support material extend in a perpendicular to the first plane; and b) at least some of the layers of part material and support material are separated from each other to form a gap between the layers of part material and layers of support material; application of heat and pressure to the part material and support material such that a portion of the part material and support material flows into and at least partially fills the gap between the part material and support material.