Copper Workpiece Chemical Polishing for Complex AM Surfaces
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Solution Overview
Problem
Existing polishing methods for copper or copper alloy workpieces with complex structures, particularly those produced by additive manufacturing, fail to achieve a smooth and bright surface finish, leading to performance issues due to surface roughness and potential corrosion.
Innovation Solution
A two-step method involving immersion of the workpiece in an iron salts aqueous solution followed by an oxidizing aqueous solution containing fluoride and copper oxidizer compounds, without the use of abrasive particles, to achieve a polished and brightened surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical mechanical polishing is used on copper workpieces with complex structures, then a smooth surface can be achieved, but the process becomes too complex and requires specialized equipment with abrasive pads that cannot access complex geometries
Solution Approach 1:
The patent replaces the mechanical polishing system (abrasive pads, pressure application, complex equipment) with a chemical system (immersion in iron salts solution followed by oxidizing solution with fluoride). This substitution allows the workpiece to be polished simply by immersion, eliminating the need for complex mechanical polishing equipment and making the process accessible to complex geometries.
Solution Approach 2:
The patent introduces iron salts solution as an intermediary medium that facilitates the polishing process. The iron salts act as a mediator between the copper surface and the oxidizing solution, enabling controlled chemical reactions that achieve polishing without direct mechanical contact. This intermediary approach simplifies the overall process while maintaining effectiveness on complex structures.
2Manufacturing precision
If mechanical polishing with abrasive particles is used, then surface smoothness is improved, but the workpiece may suffer from embedded particles and increased corrosion susceptibility
Solution Approach 1:
The patent eliminates mechanical abrasion and abrasive particles entirely, replacing them with a chemical polishing mechanism using iron salts and oxidizing solutions. This prevents embedding of abrasive particles in the copper surface while achieving the desired smoothness, thereby avoiding the corrosion susceptibility associated with mechanically polished surfaces.
Solution Approach 2:
The patent changes the fundamental parameter of the polishing mechanism from mechanical to chemical. By using controlled chemical reactions (reduction with iron salts, oxidation with fluorinated oxidizing solution) instead of mechanical abrasion, the process achieves surface smoothing without the harmful effects of particle embedding, thus improving corrosion resistance.
3Adaptability or versatility
If additive manufacturing is used to create complex topology structures, then design flexibility and functionality are improved, but surface roughness increases and impedes performance
Solution Approach 1:
The patent applies chemical polishing through immersion in iron salts and oxidizing solutions, which can uniformly treat complex additive manufactured surfaces without the geometric constraints of mechanical polishing. This approach effectively reduces surface roughness on complex topology structures while preserving the design flexibility achieved through additive manufacturing.
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 method results in a smoother and brighter surface with improved corrosion resistance, suitable for complex structures, reducing surface roughness and enhancing performance in applications requiring high protection against corrosive elements.
Implementation Method 1
introducing the copper or copper alloy workpiece in an aqueous solution comprising iron salts
Implementation Method 2
introducing the workpiece in an oxidizing aqueous solution comprising a copper oxidizer compound and a fluoride compound
Data Source
AI summary
The present invention relates to a method of polishing and brightening a workpiece of copper or copper alloy. The method of the invention is especially useful in workpieces having a complex structure such as those produced by the additive manufacturing of metals.