Solder Paste Stencil with Precision Powder Coating

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Solution Overview

Problem

Current solder-paste stencilling technologies face challenges in maintaining adequate and repeatable solder-paste volume, especially with small stencil openings, and suffer from poor durability due to non-stick coatings peeling off or wearing out quickly, leading to high defect rates in printed circuit board manufacturing.

Innovation Solution

A template with precision powder treatments on its laminar faces and perforations, including a first treated area on the bottom, a second treated area on the top, and a third treated area on the bottom, enhances solder-paste application by maintaining consistent paste volume and reducing waste, with aluminium oxide powder used for improved durability and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If non-stick coatings are applied to stencil surfaces, then paste release properties are improved, but coating durability deteriorates (peeling off and wearing out in 2-3 weeks)

Engineering Contradiction:

Improvepaste release propertiesVSAvoidcoating durability

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent applies a disposable protective film on the stencil surface that is intentionally designed to be short-lived and easily replaceable. This film provides temporary non-stick properties during use, and when it wears out or peels off, it is simply discarded and replaced with a new film rather than attempting to maintain the original coating. This resolves the contradiction by accepting the short lifespan of the surface treatment as a feature rather than a defect.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent introduces a protective film as an intermediary layer between the stencil surface and the solder paste. This intermediate layer provides the desired non-stick properties without requiring permanent modification to the stencil itself. The film acts as a sacrificial mediator that protects the stencil while providing the necessary release characteristics during the printing process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of moving object

If stencil opening sizes are reduced for miniaturisation, then electronic card density is improved, but solder-paste volume control deteriorates (inadequate and non-repeatable volumes)

Engineering Contradiction:

Improveelectronic card densityVSAvoidsolder-paste volume control

Core Design Contradiction:

Area of moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the surface energy parameters of the stencil by applying a protective film with specific surface properties. This parameter change allows for better paste release from small opening sizes, enabling adequate and repeatable paste volumes even when the stencil openings are reduced for miniaturisation purposes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The protective film is applied specifically to the areas where paste release is critical - the stencil opening surfaces. This localized treatment ensures that the surface properties are optimized precisely where needed for small opening stencils, improving paste volume control at the critical interfaces without affecting other parts of the stencil.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional stencils are used without protective treatments, then manufacturing simplicity is maintained, but defect rates increase (up to 70% of PCB manufacturing defects)

Engineering Contradiction:

Improvestencil manufacturing simplicityVSAvoidPCB manufacturing defect rate

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies a protective film to the stencil before the actual printing process begins. This preliminary action prepares the stencil surface in advance to prevent paste adhesion issues, ensuring reliable paste release from the start of production and reducing defects before they occur during the printing process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective film serves as a cushioning layer that prevents direct contact between the solder paste and the stencil surface. This beforehand protection compensates for potential adhesion problems that would otherwise occur, acting as a buffer that ensures consistent paste release and reduces manufacturing defects.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS11297719B2Template that improves solder-paste stenciling and production method thereof

Publication Date: 2022.04.05 VILLALVAZO JIMMY MR

AI summary

A template or stencil with perforations, which improves solder-paste stencilling on an object, includes: a first area treated with precision powder on a bottom laminar face of the template, the treated face covering at least an area where perforations are distributed; a second area treated with precision powder on a top laminar surface of the template, the second treated area encircling the perforations; and a third area treated twice with precision powder on the bottom laminar surface, the third area encircling the perforations of the template. A method for producing a template that improves solder-paste stencilling on an object is also provided, as is and to a method for the improved application of solder-paste on an object, such as a printed circuit board.