Stainless Steel Sink Assembly With Hidden-Weld Integrated Strainer

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Solution Overview

Problem

High-end stainless steel sinks with large wall thicknesses cannot have seamless integrated strainers due to tearing and cracking issues during deep drawing, and they also suffer from unsightly seams where dirt collects, unlike lower-end models.

Innovation Solution

A method involving stainless steel with a polished texture, where a hole is formed, the edge is bent to create a stub, a strainer is welded to the stub with a recessed weld for mechanical surface treatment to reduce visibility, and the polished texture is maintained by pre-polishing before bending and welding, ensuring an attractive and cost-efficient sink with an integrated strainer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If deep drawing is used to manufacture sinks with integrated strainers, then seamless design is achieved, but stainless steel thickness is limited to 0.6-0.8mm and cannot be used for high-end thick sinks

Engineering Contradiction:
Improveseamless integrated strainer designVSAvoidstainless steel thickness capability
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The manufacturing process is divided into separate steps: first forming the sink body with the hole, then separately forming the strainer component, and finally joining them through welding. This segmentation allows each component to be optimized independently - the sink body can be made from thick stainless steel (≥0.9mm) without deep drawing constraints, while the strainer can be precisely formed separately, and the joint can be hidden within the recessed area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The strainer is extracted as a separate component from the deep drawing process. Instead of forming the strainer and sink body as a single integrated piece through deep drawing, the strainer is formed separately and then attached to the sink body, allowing thick stainless steel to be used for the sink body while still achieving an integrated appearance.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If separate strainer is clamped to the sink hole edge, then manufacturing is simpler, but an annular seam is created where dirt collects

Engineering Contradiction:
Improvestrainer attachment processVSAvoiddirt accumulation in seam
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The strainer and sink body are merged into a single integrated assembly through welding. The strainer is welded to the edge of the hole in the sink body, creating a unified structure that eliminates the annular seam between separate components. This welding integration maintains manufacturing simplicity while eliminating the dirt-trapping gap.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The welding process, which could potentially create visible seams or defects, is performed in a way that converts it into a benefit. The weld is placed within a recessed area that is not visible from above, and the welding process creates a strong, seamless bond that actually improves the appearance by eliminating the annular gap, turning a potential defect into an aesthetic advantage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Shape

If welding is performed after polishing the first side, then the polished surface is maintained, but polishing lines become visible in the welded area

Engineering Contradiction:
Improvepolished texture of bottom sectionVSAvoidvisibility of polishing lines
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The first side of the stainless steel is polished before the bending and welding operations. By performing the polishing treatment in advance, the polished surface is established on the areas that will be visible from above. The subsequent welding is confined to the recessed area, so any polishing lines created during welding are hidden and not visible from above, eliminating the appearance problem.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The welding operation is moved from the visible surface dimension to the hidden recess dimension. By confining the welding to the recessed area that is not visible from above, the polishing lines created during welding are placed in a different spatial dimension (the recessed depth) where they cannot be seen, thus maintaining the aesthetic appearance of the polished surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Manufacturing precision

If the whole first side is polished after welding, then weld visibility is reduced, but polishing lines appear in non-welded areas and cost increases

Engineering Contradiction:
Improvevisibility of weldVSAvoidpolishing operation complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The polishing treatment is applied selectively to specific areas rather than the entire first side. The recessed area is prepared to receive the weld, and any polishing needed is confined to that local region. This localized approach maintains the aesthetic appearance where needed while avoiding the creation of visible polishing lines in the non-welded visible areas, and significantly reduces the polishing operation and associated costs.

Inventive Principle:
Principle #3Local quality

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

Enables the production of high-end sinks with large wall thicknesses having a seamless integrated strainer, reducing dirt collection areas and maintaining an attractive polished texture while being cost-effective.

Implementation Method 1

welding a strainer to the edge of the stub by abutting the circumferential edge of the strainer to the distal circumferential edge of the stub

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

subjecting the area of the resulting weld inside the recess to a mechanical surface treatment reducing the visibility of said weld

Methodology Applied
Scientific EffectGrinding: Abrasion

Implementation Method 3

mechanical surface treatment comprises grinding and polishing

Methodology Applied
Scientific EffectPolishing: Abrasion

Data Source

PatentEP2839921B1A method of manufacturing a sink of stainless steel
Publication Date: 2016.05.18 CARESSI
  • EP2839921B1 patent drawingFigure 1
  • EP2839921B1 patent drawingFigure 2A~2B
  • EP2839921B1 patent drawingFigure 2C~2E

AI summary

The invention relates to a method of manufacturing a sink of stainless steel, said sink comprising a bottom section, said bottom section having - a first side facing the lumen of the sink, - a second side opposite of the first side and facing away from the lumen; and - a sink hole with an integrated strainer. According to the invention, a hole is provided in a bottom section, the edge of the hole is bent away from the lumen to form a stub, and a strainer is welded to the edge of the stub. Then the area of the weld inside the recess is subjected to a mechanical surface treatment reducing the visibility of the weld.