Single-Sided Copper PCB Drilling for Wave Soldering

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Solution Overview

Problem

The production of printed circuits with electronic components soldered on the opposite side of the circuit requires costly and time-consuming metallising processes, leading to environmental contamination, especially when using thin nonconductive materials like polymide or polyvinyl fluoride films, as existing methods involve drilling and metallising holes for electrical connections.

Innovation Solution

Drilling holes in the support before rolling and applying a copper layer on one side to cover these holes, followed by drilling smaller holes inside the initial holes to facilitate tin flow during wave soldering, eliminating the need for metallising and reducing copper usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support is drilled after rolling with copper layer on both sides, then electrical connections are established, but the metallising process is expensive, time-consuming and environmentally contaminating

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidproduction time and cost
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The support is drilled before rolling the copper layer, so that the holes are already in place before the copper is applied. This preliminary drilling action eliminates the need for subsequent metallising operations while ensuring proper electrical connection paths are established.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts and eliminates the metallising operation from the traditional three-step process. By drilling holes before rolling and using a single-sided copper application, the complex and contaminating metallising step is completely removed from the production process.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If copper layer is applied on both sides of the support, then electrical connections are ensured, but copper consumption increases

Engineering Contradiction:
Improveelectrical connectionVSAvoidcopper consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

Instead of applying copper symmetrically on both sides of the support, the invention uses an asymmetric approach by rolling copper only on one side. The holes are drilled before rolling, allowing the single-sided copper layer to still provide necessary electrical connections through the pre-drilled holes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention extracts the unnecessary copper application from the second side of the support, eliminating redundant copper usage while maintaining functional electrical connections through the pre-drilled holes and single-sided copper layer.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If metallising operation is performed, then electrical connections are made, but environmental contamination increases

Engineering Contradiction:
Improveelectrical connectionVSAvoidenvironmental contamination
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention completely removes the metallising operation from the process sequence. By drilling holes before rolling and using a single-sided copper application, the harmful metallising step is extracted and eliminated, eliminating associated environmental contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potentially harmful metallising process into a beneficial simple rolling operation. By reordering operations to drill before roll, the process transforms a harmful chemical treatment into a simple mechanical operation with environmental benefits.

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

4Reliability

If holes are drilled in the support, then electrical connections are enabled, but the simple drilling operation does not guarantee safe fixing of electronic components

Engineering Contradiction:
Improveelectrical connectionVSAvoidcomponent fixing reliability
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Holes are drilled as a preliminary action before rolling the copper layer. This ensures that the hole positions are precisely established in the support structure before any copper application, providing accurate positioning for subsequent component soldering and fixing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pre-drilled holes serve as intermediaries that bridge the support structure and the copper layer. These holes provide defined pathways for electrical connections and serve as precise reference points for component placement and fixing, ensuring both electrical functionality and manufacturing precision.

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

This process significantly reduces costs, operating time, and environmental impact by eliminating the metallising step and ensuring reliable electrical connections through the passage of tin during wave soldering.

Implementation Method 1

the first operation consists in rolling both sides of the support with sheets of copper or any other conductive material

Methodology Applied
Scientific EffectRolling:

Implementation Method 2

the third operation consists in metallising the holes drilled on the laminated support to make the electrical connections in each hole, whose walls are covered with conductive material, usually copper, to favour the flow of the tin drop through and over the hole during the wave soldering process

Methodology Applied
Scientific EffectWave soldering:

Data Source

PatentEP2116114B1Production process of printed circuits on which electronic components without leading wire are soldered
Publication Date: 2010.08.11 CISEL SRL CIRCUITI STAMPATI PER APPL ELETTRONICHE
  • EP2116114B1 patent drawingFigure 1~8
  • EP2116114B1 patent drawingFigure 9~14

AI summary

The present patent application relates to a production process of printed circuits on which electronic components without leading wire situated on the opposite side with respect to the circuit printed side are soldered. In particular, the said process provides for drilling the support (10), rolling it with a layer of conductive material (20) on only one (10a) of the two sides (10a and 10b) and making the circuits on the said side (10a).