Pretensed Fabric Tool for Multilayer PCB Internal Bonding

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Solution Overview

Problem

Multilayer printed circuit boards with high internal layer interconnection density and combining rigid and flexible areas face misalignment issues due to unpredictable mechanical expansion and shrinkage, leading to high rejection rates, and existing tools are not versatile enough to accommodate internal bonding points without disturbing the magnetic field or heating up.

Innovation Solution

A tool using a pretensed, non-electrically conductive fabric with a thickness less than 0.1 mm, supported by a frame, allows for flat and stable support of the circuit board, preventing magnetic field disruption and enabling internal point bonding by applying induction electrodes on the fabric surfaces, rather than directly on the board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional tools with plate shape and recesses are used to support the bundle, then the tool can be used for manufacturing different bundles with standard dimensions, but the tool cannot accommodate internal bonding points and must disturb the magnetic field or heat up

Engineering Contradiction:

Improveability to accommodate internal bonding pointsVSAvoidmagnetic field disruption and unwanted heat generation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a non-conductive fabric as an intermediary layer between the tool and the circuit board bundle. This fabric allows induction electrodes to be applied on its surface for internal point bonding without the tool itself disturbing the magnetic field or generating unwanted heat, while still providing stable support for the bundle

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional rigid plate support structure with a flexible non-conductive fabric stretched on a frame. This substitution allows the support tool to be electromagnetically transparent (not interfering with induction welding) while maintaining the mechanical function of holding the bundle flat and stable

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If layers are bonded at internal points to control expansion and shrinkage, then misalignment between rigid and flexible layers is reduced, but custom-made tools are required for each circuit

Engineering Contradiction:

Improvealignment precision between layersVSAvoidcustom tool design for each circuit

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The non-conductive fabric support tool provides a universal platform that can accommodate internal bonding points at any location on the circuit board. The fabric surface allows flexible placement of induction electrodes according to specific circuit requirements without requiring custom tool designs, making the same tool adaptable to different circuit configurations

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If the tool completely covers the lower face of the bundle, then stable support is provided, but the magnetic field cannot traverse the bundle and the tool heats up

Engineering Contradiction:

Improvesupport stabilityVSAvoidunwanted heat generation in tool

Core Design Contradiction:

Stability of the object's compositionVSTemperature

Solution Approach 1:

The non-conductive fabric acts as an intermediary that allows magnetic field penetration while providing support. The fabric's non-conductive nature enables the magnetic field to traverse through it to reach the bundle without inducing currents and heating the support structure, while still covering and stabilizing the entire lower face of the bundle

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution provides a versatile tool for reliable internal bonding of multilayer printed circuit boards, reducing misalignment and rejection rates by maintaining a flat surface and avoiding unwanted heat generation, while allowing for flexible placement of bonding points.

Implementation Method 1

generating a magnetic field traversing the bundle precisely through said turns or spots, electric currents being induced therein

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

electric currents being induced therein which due to the Joule effect generate enough heat to melt the resin layers

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9826644B2Tool, method and machine for manufacturing multi-layer printed circuit boards

Publication Date: 2017.11.21 CHEMPLATE MATERIALS

AI summary

A tool for supporting multilayer printed circuit boards during manufacture having a frame in which there is fixed a pretensed, non-electrically conductive fabric which has a thickness less than 0.1 mm and which can be accessed by its two faces. The tool allows the induction bonding of the layers at internal points of the bundle following a method in which the bundle is placed on the tool and at least one of the welding electrodes used in the welding operation is applied on the lower face of a fabric of the tool supporting the bundle. A machine especially suitable for putting the method into practice includes C-shaped magnetic cores, the arms of which are long enough to reach the internal points of the bundle.