Chemical Polishing Flow Paths for AM Internal Cavity Finishing
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Solution Overview
Problem
Additive manufactured (AM) metal workpieces with complex internal cavities face issues such as metal debris accumulation, surface roughness, and difficulty in removing temporary support structures, especially in small and tortuous cavities, using traditional mechanical finishing methods, which leads to inefficiencies and inconsistencies in surface finishing and dimension accuracy.
Innovation Solution
A chemical polishing method is employed to remove metal debris and temporary support structures from internal cavities, utilizing customized connectors to ensure uniform chemical solution delivery and temperature control, with a heated buffer bath and recirculation system to maintain consistent chemistry and prevent gas bubbles, allowing for precise monitoring of stock removal and surface finishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical finishing methods (abrasive grinding, magnetic abrasive finishing) are used on internal cavities, then surface roughness is reduced, but residual debris remains inside the cavities requiring subsequent removal
Solution Approach 1:
The patent replaces mechanical finishing methods with a chemical etching process that uses chemical reactions to remove material from internal cavities. This substitution eliminates the generation of mechanical debris while achieving the desired surface finish, as the chemical process dissolves material rather than mechanically removing it.
Solution Approach 2:
The patent changes the fundamental parameter of the finishing process from mechanical to chemical. By using controlled chemical etching with specific etchants and processing conditions, the system achieves surface finishing without producing residual debris that would require additional removal steps.
2Strength
If temporary support structures are used in internal cavities with cross section greater than 3 mm, then heat transfer and mechanical stability are improved, but removal of supports becomes difficult or impossible with traditional mechanical techniques
Solution Approach 1:
The patent uses chemical etching to remove temporary support structures from internal cavities, replacing mechanical removal techniques. This chemical approach can access and remove supports from narrow, tortuous pathways where mechanical tools cannot reach, completely eliminating the support structures without leaving residual debris.
3Stability of the object's composition
If AM parts are built with identical parameters in the same machine, then manufacturing consistency is maintained, but significant variances in surface roughness and metal debris quantities occur from part to part
Solution Approach 1:
The patent implements a quality verification process that inspects each part after chemical etching to confirm removal of metal debris and achievement of desired surface finish. This feedback mechanism identifies parts that require reprocessing, ensuring consistent quality output despite variations in the additive manufacturing process.
4Manufacturing precision
If mechanical finishing techniques are used on internal cavities, then surface roughness is reduced, but the process cannot successfully treat cavities with cross-sectional areas of less than 1 mm²
Solution Approach 1:
The patent replaces mechanical finishing methods with chemical etching, which can access and finish internal cavities of any size including those with cross-sectional areas less than 1 mm². The chemical process flows through narrow passages and tortuous pathways that mechanical tools cannot reach, providing universal applicability across all cavity geometries.
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 chemical polishing method effectively removes metal debris and support structures, achieving uniform surface roughness and desired internal dimensions, reducing post-processing checks and pre-processing inspections, while ensuring safety and environmental concerns are mitigated through controlled chemical handling and monitoring.
Implementation Method 1
A chemical polishing method is employed to remove metal debris and temporary support structures from internal cavities
Implementation Method 2
with a heated buffer bath and recirculation system to maintain consistent chemistry
Implementation Method 3
heated buffer bath and recirculation system to maintain consistent chemistry and prevent gas bubbles
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
A method for chemical processing an internal cavity of an additive manufactured (AM) metal workpiece is disclosed in which a connector is provided in fluid connection with the internal cavity and a chemical polishing solution is flowed through the connector and the internal cavity to process the internal cavity to a desired finish.