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Article
Publication date: 1 September 2003

Martin Goosey and Rod Kellner

New legislation to encourage the recycling of end of life electronics and moves to implement sustainable development in electronics manufacturing have focussed attention on the…

3142

Abstract

New legislation to encourage the recycling of end of life electronics and moves to implement sustainable development in electronics manufacturing have focussed attention on the large quantity of printed circuit boards (PCBs) being consigned to landfill. Also, in a recent investigation conducted on behalf of the UK's Department of Trade and Industry, the need for new methodologies for dealing with end of life circuit boards was identified as a priority issue. Within the UK it is estimated that ∼50,000 tonnes per annum of PCB scrap is currently generated and investigations indicate that only ∼15 per cent is subjected to any form of recycling, with the remainder consigned to landfill. This paper reports the results of a scoping study carried out to identify the technologies and processes that can be used to recycle materials from end of life PCBs.

Details

Circuit World, vol. 29 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 8 February 2011

Andrew J. Cobley, Lindsay Edgar, Martin Goosey, Rod Kellner and Timothy J. Mason

Previous studies have proven that, under optimised ultrasonic conditions, a range of materials used in electronic manufacturing can be sonochemically surface modified using benign…

Abstract

Purpose

Previous studies have proven that, under optimised ultrasonic conditions, a range of materials used in electronic manufacturing can be sonochemically surface modified using benign solutions at low temperature. The purpose of this paper is to focus on a specific process, namely, the desmearing of through holes in printed circuit boards (PCB). The objective was to determine whether the introduction of low frequency ultrasound (20 kHz) to the “etch” stage of a standard “swell and etch” desmear system could enable reduced temperature processing and the use of less chemistry in the permanganate solution.

Design/methodology/approach

The study was divided into three main stages. In the first “screening” phase, the effect of ultrasound in the etch solution was studied by measuring the weight loss after desmear on a PCB laminate material (Isola 370HR). Factors such as etch temperature and concentration of permanganate (including permanganate‐free) were varied. In stage 2, confirmatory runs were carried out on the most promising conditions from the screening work and through holes in a four‐layer multi‐layer board (MLB) were assessed for smear removal using a scanning electron microscope (SEM). Finally, a four‐layer MLB was desmeared through the most promising ultrasonic process and then metallized at a PCB manufacturer. Thermal shock testing was subsequently carried out and sections from the board assessed for inter‐connection defects (ICDs).

Findings

The initial screening study indicated that, whenever ultrasound was used in the etch stage of the desmear process, significantly higher weight loss was achieved compared to a standard “silent” process. This effect was most pronounced when permanganate was removed from the etch solution and, in this situation, weight loss could be an order of magnitude higher than the silent equivalent. Further testing on through holes suggested that smear‐free inner‐layers could only be guaranteed if permanganate was present in the etch solution but that ultrasound again improved smear removal. Final testing under semi‐production conditions confirmed that, if ultrasound was employed in the etch part of the desmear process, then a reduction in processing temperature from 85°C to 60°C could be achieved and the permanganate concentration halved (65 to 33 g/L) whilst still achieving ICD‐free boards.

Originality/value

The paper indicates the feasibility of using ultrasound to reduce temperatures and chemical concentrations used in the permanganate etch solution, whilst still producing through holes with no ICDs.

Details

Circuit World, vol. 37 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 June 2004

Rod Kellner

Printed circuit boards (PCBs) requiring component attachment, whether leaded or surface mount technology, must have the exposed copper land areas coated with a protective finish…

449

Abstract

Printed circuit boards (PCBs) requiring component attachment, whether leaded or surface mount technology, must have the exposed copper land areas coated with a protective finish. This protective coating must not inhibit solderability and at the same time must act as a barrier for preventing the copper from oxidizing and the inevitable assembly problems that would ensue for the end‐user. Globally, the predominant surface finish in the PCB industry is hot air solder levelling (HASL). Driven by the adoption of solder mask over bare copper, HASL was developed as a reliable method of applying solder to the copper surfaces after solder mask. During HASL, a thin layer of solder is deposited onto the exposed copper by passing the boards through a hot, molten wave (or pot) of solder and subsequently blowing the excess solder from the boards using high velocity hot air. This process has been increasingly under scrutiny due to environmental and safety issues (hazardous waste, lead exposure, etc.), technological limitations (fine‐pitch device assembly) and equipment maintenance cost. This paper reviews the major alternative surface finishes being currently deployed and additionally seeks to give an overall assessment of the broader environmental aspects of such finishes.

Details

Circuit World, vol. 30 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 February 2012

Andy Ballantyne, Greg Forrest, Martin Goosey, Asta Griguceviciene, Jurga Juodkazyte, Rod Kellner, Aleksandr Kosenko, Rimantas Ramanauskas, Karl Ryder, Algirdas Selskis, Rima Tarozaite and Erik Veninga

The purpose of this paper is to detail progress on the European Commission supported FP7 ASPIS project that is undertaking a multi‐faceted approach to develop novel and improved…

Abstract

Purpose

The purpose of this paper is to detail progress on the European Commission supported FP7 ASPIS project that is undertaking a multi‐faceted approach to develop novel and improved nickel‐gold (ENIG) solderable finish chemistries and processes in order to overcome issues such as “black pad” that are known to cause reliability issues.

Design/methodology/approach

The ASPIS project has four key and discrete approaches; research into “black pad” formation mechanisms, development of new aqueous chemical deposition methods, formulation of new processes based on ionic liquids and the development of prognostic screening tools to enable early prediction of reliability issues.

Findings

Key factors influencing “black pad” formation include immersion gold bath pH value, concentration of citrate and thickness of the immersion gold layer. In addition, copper substrate preparation is also important. Work to develop new metal deposition processes using ionic liquids has also been demonstrated and may provide a viable alternative to more conventional aqueous based chemistries, thereby enabling some of the conditions that lead to “black pad” to be avoided.

Research limitations/implications

This paper summarises the work carried out in the first year of a three‐year project and so the outputs to date are relatively limited. The project is continuing for another two years, when further progress will be made. It is hoped to report this progress in a future update paper.

Originality/value

The ASPIS project has undertaken multiple approaches to the development of new high reliability nickel gold finishes and this combination of approaches should offer synergies over more discrete traditional methodologies. As well as undertaking a detailed analysis of the mechanisms causing reliability problems, radical new formulation and prognostic approaches are also being developed.

Article
Publication date: 9 February 2010

Martin Goosey and Rod Kellner

The purpose of this paper is to present the details of key best practices that can help printed circuit board (PCB) manufacturing companies to optimize energy consumption…

2285

Abstract

Purpose

The purpose of this paper is to present the details of key best practices that can help printed circuit board (PCB) manufacturing companies to optimize energy consumption, conserve materials, and reduce waste and costs.

Design/methodology/approach

Various individual opportunities for making energy saving are discussed along with the accompanying manufacturing best practices.

Findings

There are many opportunities to reduce energy consumption across the whole PCB manufacturing process. Additional savings may also be made by enhancements to the broader activities within PCB manufacturing plants.

Research limitations/implications

The paper summarises key findings that have been reported in a much larger Best Practice Guide and due to space considerations the amount of information given is somewhat restricted.

Originality/value

The paper details how the introduction of best practices in each stage of the PCB manufacturing process can lead to material and energy savings that have value in helping board makers to reduce costs. Readers are directed to a larger Best Practice Guide which is freely available from the SurfEnergy web site.

Details

Circuit World, vol. 36 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 February 2012

Martin Goosey and Rod Kellner

The purpose of this paper is to investigate the potential for using chitin and chitosan sustainable materials to absorb copper from PCB manufacturing effluent and to report the…

Abstract

Purpose

The purpose of this paper is to investigate the potential for using chitin and chitosan sustainable materials to absorb copper from PCB manufacturing effluent and to report the results of an initial feasibility study aimed at demonstrating proof of concept.

Design/methodology/approach

Crab shells and prawn shells, both waste products of the seafood industry, as well as chitosan, were evaluated as potential absorbents for recovering copper present at low levels in the manufacturing effluent produced in a UK‐based PCB manufacturing facility. Various conditions were investigated and efforts were also made to recover absorbed copper via a regeneration process that enabled the metal to be electroplated from solution.

Findings

Although only a short feasibility study, conditions were found that enabled copper to be absorbed by the ground crab shells and chitosan and then subsequently recovered by electrowinning to produce the metal.

Research limitations/implications

Although successful as a feasibility study, the experimental work highlighted the large number of variables that need to be investigated and optimised in order to obtain the most efficient copper capture and recovery. Further work needs to be carried out to determine these optimum conditions and to investigate the potential for recovery of other metals from a wider range of solutions.

Originality/value

The paper details how individual treatment technologies can be combined to enable a much more sustainable approach to PCB manufacturing which offers the benefits of reduced effluent metal levels, metal recovery and a novel use for another sector's waste products.

Content available
Article
Publication date: 1 June 2000

48

Abstract

Details

Circuit World, vol. 26 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Content available
Article
Publication date: 3 February 2012

Martin Goosey

278

Abstract

Details

Circuit World, vol. 38 no. 1
Type: Research Article
ISSN: 0305-6120

Abstract

Details

Circuit World, vol. 38 no. 4
Type: Research Article
ISSN: 0305-6120

Content available
Article
Publication date: 23 November 2010

Pete Starkey

105

Abstract

Details

Circuit World, vol. 36 no. 4
Type: Research Article
ISSN: 0305-6120

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