Partial Coating of Gemstones via Salt Crust Masking
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Solution Overview
Problem
Existing methods are unsuitable for achieving a patina effect on three-dimensional objects, particularly gemstones with sloping surfaces, as they fail to provide a cost-effective and visually distinct partial coating, and classic masking techniques are not applicable to irregular shapes.
Innovation Solution
A method involving hydrophobization, statistical distribution of liquid and powdery substances, drying to form crusts, and subsequent metal coating, followed by removal of crusts to achieve a patina effect on three-dimensional objects made of various materials like glass, ceramic, or gemstones, using spray nozzles and PVD techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If classic masking techniques are used for partial coating, then coating precision can be achieved on flat surfaces, but the method cannot be applied to irregular three-dimensional shapes like gemstones
Solution Approach 1:
The coating process is segmented into distinct stages: first applying a liquid layer that selectively wets only certain facets, then applying a powder layer that adheres only to the wetted areas. This segmentation allows each stage to optimize for its specific function, achieving both adaptability to 3D shapes and coating precision.
Solution Approach 2:
The invention transitions from traditional two-dimensional masking approaches to a three-dimensional solution by using spray nozzles that can access and coat faceted surfaces from multiple angles. The liquid-powder sequence is applied in a way that respects the three-dimensional geometry of gemstones and other irregular objects.
2Manufacturing precision
If vapor deposition with masks is used, then partial coating can be achieved, but the method is complex and cannot handle irregular shapes
Solution Approach 1:
The invention replaces the complex mechanical masking system with a chemical/physical sequence: liquid application followed by powder application. The liquid acts as a temporary adhesive medium that selectively binds powder to specific surfaces, eliminating the need for physical masks and their associated complexity.
Solution Approach 2:
The liquid layer serves as an intermediary substance between the substrate and the powder coating. It temporarily modifies surface properties to enable selective powder adhesion, then is removed after the powder adheres, leaving only the desired partial coating without requiring complex masking apparatus.
3Manufacturing precision
If traditional coating methods are used on faceted surfaces, then complete coating is achieved, but distinct partial coating patterns cannot be formed
Solution Approach 1:
The invention applies local quality by making the liquid layer's wetting properties specific to certain facets of the object. Different facets receive different treatments based on their orientation and surface properties, resulting in selective powder adhesion that creates distinct patterns while maintaining clear boundaries between coated and uncoated areas.
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 effectively coats small three-dimensional objects with sloping surfaces, providing a stable and visually pronounced patina effect, which is not achievable with traditional masking methods, and the coated objects exhibit stability comparable to fully coated items in jewelry industry tests.
Implementation Method 1
optional hydrophobization of the surface of the three-dimensional object
Implementation Method 2
drying of the surface to form spatially limited, statistically distributed salt or powder crusts
Implementation Method 3
coating of the surface with at least one layer of a metal or metal compound
Data Source
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AI summary
The invention relates to a method for partially coating a surface of an object, comprising the following steps: (a) optional hydrophobization of the surface of the object; (b) partial application of (b1) a liquid and subsequent application of a powderous or granular substance or (b2) a solution or suspension of said powderous or granular substance in a liquid; (c) drying the surface to form spatially-delimited salt or powder crusts; (d) coating the surface with at least one layer of a metal or a metal compound; and (e) removing the salt or powder crusts that have been produced. The invention also relates to products that have been produced according to the claimed method.