Reducing material costsin PCB manufacture

GG

396

Foreword

The PCB industry in the UK has witnessed much change over the last few years as it strivesto remain competitive in a market that demands ever lower prices and ever higherproduct specifications. Environmental performance is another area where companies areunder continued pressure from their stakeholders to do better.

Material purchase and waste disposal are two costs that PCB manufacturers can take action tominimise without having to undertake major investment. A recent Envirowise study found thatcompanies could reduce raw material costs by around 15% just by implementing simple no-costand low-cost measures to reduce wastage and improve material utilisation. Can you afford toignore these potential savings?

This excellent and practical Guide explains how all companies can make significant cost savingsby taking action to improve their utilisation of laminate, chemicals and drills. I commend thisGuide and other Envirowise publications to all PCB manufacturers.

Frank CoultardManager - Components and Manufacturing ServicesIntellect

This Good Practice Guide was produced by

Envirowise

Prepared with assistance from:

Enviros Consulting LtdRod Kellner

with thanks to Graphic plc for providing photographs.

Reducing material costsin PCB manufacture

Summary

At a time when markets demand reduced prices, material costs represent an increasingproportion of turnover for printed circuit board (PCB) manufacturers in the UK.Companies are also under pressure to reduce waste costs and to improve theirenvironmental performance.

This Good Practice Guide is intended to help PCB manufacturers reduce costs, optimise processefficiency and reduce waste by improving their utilisation of laminate, chemicals and drills.Companies that adopt simple, cost-effective techniques to improve their utilisation of thesematerials could save, on average, around £120 000/year. As the industry examples in this Guideshow, some companies have saved much more.

A recent Envirowise study found that, by adopting best practice, PCB manufacturers in the UKcould:

■ reduce laminate consumption by 15 - 35%;

■ decrease chemical consumption by over 30%;

■ reduce the number of new drill bits purchased each year by 60%.

The Guide describes:

■ the potential savings from improving material utilisation;

■ the benefits of taking a systematic approach to waste minimisation;

■ how to improve laminate utilisation by rationalising panel sizes and optimising board layout;

■ how to reduce overall chemical costs by improved chemical sourcing, improved processcontrol and using improved process technology;

■ the financial benefits from regrinding drill bits for re-use;

■ the free support and information available from Envirowise.

The practical advice given in this Guide is applicable to companies of all sizes. The Guide includesa number of checklists and worksheets to help companies reduce costs by improving theirutilisation of laminate, chemicals and drills.

Contents

Section Page

1 Introduction 11.1 Why worry about material utilisation? 11.2 Are you using more materials than necessary? 21.3 Cost savings from simple measures 31.4 A systematic approach to waste minimisation 41.5 How can this Guide help? 4

2 Measuring material use to identify savings opportunities 6

3 Overcoming barriers to improved material utilisation 9

4 Improving laminate utilisation 114.1 Sources of laminate waste 114.2 Rationalising panel sizes 134.3 Improving board layout and reducing trim 144.4 Summary of best practice 16

5 Improving chemical utilisation 195.1 Improved chemical sourcing 205.2 Improved process control 235.3 Improved process technology 275.4 Summary of best practice 31

6 Reducing drill costs 326.1 Drill bit regrinding 326.2 Other opportunities 346.3 Summary of best practice 34

7 Action plan 357.1 Help from Envirowise 36

Appendix Worksheets and checklists 38

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Introduction

This Good Practice Guide aims to help printed circuit board (PCB) manufacturersimprove the efficiency of material utilisation during manufacture and thus optimiseprocess efficiency, reduce waste and enhance profitability. Following the practical advicein this Guide will also help companies to remain competitive and comply withenvironmental legislation.

1.1 Why worry about material utilisation?

Material costs represent an increasing proportion of turnover and the demand for reduced pricesmakes improved material utilisation even more important. The type, volume and technicalcomplexity of the boards will influence the scope for cost savings through improved utilisationbut all companies are likely to find savings. Industry examples in this Guide show how muchparticular companies have saved.

Improved material utilisation represents a significant business opportunity for PCB manufacturers.

■ Raw material costs are significant and form an increasing proportion of total costs for theindustry. Simple measures can reduce material consumption and thus reduce costssubstantially.

■ Most companies use more materials than they need and hence there is an opportunity toimprove efficiency.

■ Waste disposal costs will continue to rise as a result of further increases in the landfill tax andtighter legislative controls at landfill sites. For example, implementing the requirements of thelandfill directive is expected to have a significant impact on the cost of disposing of hazardous(special) wastes1.

■ Laminated materials that are wasted unnecessarily incur a large loss in value at both ends ofthe process, ie expensive raw material is wasted and little value is recovered from the waste.

■ The high volumes of laminate, photochemistry, drills, screen inks and packaging used by thePCB industry account both directly and indirectly for a wide range of environmental impacts.Improved material utilisation has a significant role in minimising environmental impacts andimproving environmental performance.

Following the advice given in this Guide will help your company to reduce costs, use materialsmore efficiently and improve its environmental performance. The Guide provides practical adviceand is based on techniques suitable for companies of all sizes. This publication concentrates on:

■ laminates (see section 4);

■ chemicals (see section 5);

■ drill bits (see section 6).

Addressing these three issues will help an average PCB manufacturer to achieve estimatedsavings of £120 000/year. You could save considerably more. For example, Graphic plcestimates it saves up to £150 000/year just by regrinding drill bits.

1 For advice and information about current regulations governing hazardous and other wastes produced by yourcompany, contact the Environment and Energy Helpline on freephone 0800 585794.

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1.2 Are you using more materials than necessary?

Many companies are using and paying for more raw materials than they actually need to use.Excessive use is generally due to poor stock control, inadequate planning and inefficientproduction practices. These factors are exacerbated by:

■ a lack of information on the potential savings from optimising material use;

■ a lack of information on the ‘business case’ for improving material utilisation;

■ a lack of information on ways to achieve material and cost savings;

■ limited resources;

■ customer pressures and requirements.

A recent Envirowise study found that laminate, process chemicals and drill bits represent thelargest annual raw material consumption and often the largest aspect of expenditure for manyPCB manufacturers (see Table 1). This study, which included discussions with suppliers and arepresentative sample of PCB manufacturers, highlighted the significant potential for reducingraw material use in these areas by adopting simple, cost-effective techniques.

The percentage savings from adopting best practice in the utilisation of laminate, chemicals anddrills are substantial (see Table 1). For the sector as a whole, these savings translate toapproximately £7 million/year. This equates to an average estimated possible saving ofapproximately £120 000/year by each PCB manufacturer in the UK.

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1.3 Cost savings from simple measures

PCB manufacturers that adopt a systematic approach to improving raw material utilisation canreduce raw material costs by some 15% at little or no cost to the business. The industryexamples2 in this Guide illustrate the savings already achieved by some PCB manufacturers (seeTable 2).

Material Average per manufacturer Estimated savings fromadopting best practice

AnnualSmall Medium/large industry Amount

companies*** companies**** total (%) (£)

Laminate 14 300 187 500 2.5 million 15 - 35 375 000 - 875 000(m2/year)*

Chemicals 30 375 5 000 30 - 37 1 500 - 1 850(tonnes/year)**

Drills 34 300 450 000 6 million 60 3.6 million(number/year)

* Laminate consumption figures based on information supplied by Isola Composites.

** Chemical consumption figures based on information from suppliers and discussions with manufacturers on per litre costsof a range of chemicals purchased.

*** Small companies are defined as having <50 employees. These companies represent 10% of PCB manufacturing byturnover.

**** Together medium/large companies represent 90% of PCB manufacturing by turnover. Medium companies (50 - 150employees) represent 55% of industry turnover and large companies (≥150 employees), 35% of industry turnover.

Table 1 Potential material savings by PCB manufacturers in the UK

2 Wherever possible, examples are taken from PCB manufacturers. Other information has been provided bysuppliers.

Company No. of Benefits* Improvement technique(s)employees

Graphic plc 150 ■ 10% saving in laminate ■ Improving board layoutraw material use and reducing trim

■ Savings of £150 000/year ■ Regrinding drill bitson drill bit costs process

Newbury 50 ■ 10% reduction in ■ Standardising panel sizesElectronics Ltd annual laminate use and board layout, and

reducing trim by 5 mm

Option 29 ■ Reduction in process costs ■ Installing a firstTechnologies Ltd from ~£1/m2 to ~£0.35/m2 generation alternative

oxide conveyor line

DDI Tewkesbury 85 ■ 10% reduction in ■ Rationalising panel Division laminate consumption sizes to improve board

over two years layout

* Company estimates.

Table 2 Summary of industry examples

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1.4 A systematic approach to waste minimisation

Using materials more efficiently is just one way of reducing operating costs. Taking a systematicapproach to minimising all types of waste will also add value to your bottom line and help youto remain competitive.

The principles underlying good waste minimisation practice are based on the waste hierarchy(see Fig 1). This is the order of preference for reducing waste based on the fact that preventionis better than cure. The higher up the hierarchy that action is taken over waste, the greater thecost savings - so the closer to the first stage of ‘elimination’, the better the savings.

In UK businesses, the cost of waste is typically 4% of turnover; in some companies, it can be ashigh as 10%. Implementing waste reduction measures as part of a waste minimisationprogramme can reduce these costs by a quarter whatever the size of the company.

If you would like to know more about saving money through waste minimisation, there is awealth of material available from Envirowise. Some useful publications for PCB manufacturersare listed in section 7.1.1. This list also contains publications with general advice on how toreduce water use and effluent generation. All Envirowise publications are available free of chargefrom the Environment and Energy Helpline on freephone 0800 585794 or via the Envirowisewebsite (www.envirowise.gov.uk).

1.5 How can this Guide help?

This Guide describes a step-by-step approach to help PCB manufacturers improve raw materialuse. Improved material utilisation will result in cost savings and improve your company’s imageby reducing its impact on the environment.

The Guide’s approach is based on obtaining answers to the following questions:

■ What is the scope in your company for savings from using materials more efficiently?

■ What is the business case for obtaining top management commitment to undertakeimprovement projects?

5

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Fig 1 The waste hierarchy

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■ How should you go about making improvements?

■ How can you:

- Reduce laminate use?

- Reduce the volumes and costs of process chemicals?

- Re-use drill bits?

- Learn about other areas for improvements in material use?

Practical advice is provided together with industry examples that illustrate how companieshave already achieved significant cost savings without compromising quality standards. Aframework for the implementation of best practice is provided by summary tables at the endof sections 4 - 6.

The Guide provides worksheets and checklists to help you identify opportunities for savingswhich are cost-effective and which do not require significant time or resources. Blank copies ofthe worksheets and checklists are given in the appendix for you to photocopy and use asrequired. These tools are also available electronically as a Microsoft® Word file that can bedownloaded from the Envirowise website (www.envirowise.gov.uk). Look for ‘tool’ on the pagedevoted to this Guide in the Publications area of the website.

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Measuring material use to identifysavings opportunities

In many cases, the best way to identify potential savings in material use is to draw up aprocess flow diagram of your manufacturing process showing the main operations andmaterials consumed. Fig 2 shows a simplified flow diagram of the PCB manufacturingprocess. The main wastes are chemicals, laminates and drills.

Design

Photo image

Develop, etch, strip

Oxide treat surface

Drill holes

Photo image

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Electroplate

Stripping/etching

Apply interlayerbonding

Electroless copper/direct plate process

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Product

Waste laminate board

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Waste chemicals

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Chemicals

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Chemicals

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Waste chemicalsEffluent

Waste chemicalsEffluent

Waste chemicalsEffluent

Waste chemicalsEffluent

Waste chemicalsEffluent

Waste chemicalsEffluent

Waste drillsWaste from holes

Waste

Fig 2 Example process flow diagram for a multi-layer PCB manufacturing process

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■ Use Fig 2 to develop a more detailed diagram of your own operations.

■ Use the information from your process flow diagram to identify the main wastes arising fromeach process stage. Use a worksheet like the example shown in Fig 3 overleaf to help youdocument these wastes and their true cost to the company. A blank copy of this worksheetis given in the appendix.

■ Investigate why waste is produced at each stage of the process.

■ Identify priority wastes for action (eg high cost and/or large volume).

■ Identify potential ways of reducing priority waste streams (see sections 4 - 6).

■ Examine the economic and technical viability of identified options.

Further advice and information about waste minimisation in general is given in:

■ WasteWise: increased profits at your fingertips (IT313) - an interactive CD-ROM tohelp you find increased profits from your desktop

■ Saving money through waste minimisation: raw material use (GG25)

■ Cutting costs by reducing waste: a self-help guide for growing businesses (GG38C)

These publications are available free of charge through the Environment and EnergyHelpline on 0800 585794 or via the Envirowise website (www.envirowise.gov.uk).

Useful Envirowise publications

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Overcoming barriers to improvedmaterial utilisation

Many waste minimisation programmes fail to be completed or to reach their fullpotential. The main reasons for this are:

■ lack of management commitment;

■ insufficient staff awareness or contribution;

■ lack of resources.

Before you start your waste minimisation programme, it is important to ensure that these issuesare not likely to inhibit its success. Table 3 overleaf provides information about the main barriersyou may face when seeking to improve material use and highlights some of the techniques thatcan be used to remove them.

There is a common misconception that waste minimisation programmes cost money. Typically,waste minimisation could save your company up to 1% of business turnover, either as extraprofit or in reduced operating costs.

To obtain these cost savings, it is important to have the backing of senior management for thewaste minimisation programme from the start. This will help to ensure that sufficient staff andfinancial resources (if required) are made available in order to realise the potential savings.

It is also important to ensure that all employees are aware of what the programme is aiming toachieve. You will need information from them in order to prioritise wastes and implementimprovements.

A successful waste minimisation programme is based on:

■ communicating the financial and wider benefits of waste minimisation;

■ dispelling any myths or misconceptions about waste costs.

More information to help you address and overcome these potential problems isgiven in:

■ Saving money through waste minimisation: teams and champions (GG27)

■ Waste minimisation pays: five business reasons for reducing waste (GG125)

■ WasteWise: increased profits at your fingertips (IT313) - an interactive CD-ROM tohelp you find increased profits from your desktop

These publications are available free of charge through the Environment and EnergyHelpline on 0800 585794 or via the Envirowise website (www.envirowise.gov.uk).

Useful Envirowise publications

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Table 3 Barriers and solutions to successful waste minimisation

Barriers Solutions

Gaining senior management commitment

Improving material utilisation requires thesupport and commitment of seniormanagement. This may be hard to gain if:

■ team working across departments(required for successful materialutilisation) is not in place;

■ the company culture is not open tochange;

■ the company structure does not allowadvantage to be taken ofopportunities for improvement.

■ Set up a waste minimisation team withrepresentatives from all departments.

■ Emphasise opportunities for earlysuccess and any cost savings that havealready been achieved.

■ Communicate the savings already madeby other companies (see the industryexamples in this Guide).

■ Stress the short payback periods for anyinvestment.

■ Highlight known major sources of wasteand explain the financial costsassociated with the waste (eg the rawmaterial and disposal costs).

■ Discuss any perceived difficulties.

■ Point out the potential impact ofenvironmental legislation.

■ Gain the support of line managers (itwill be difficult to make any progresswithout this).

■ Start by implementing improvementswhich give immediate savings throughno-cost or low-cost measures.

Awareness

Lack of awareness regarding:

■ the benefits of improvingperformance;

■ materials issues;

■ economic and business benefits;

■ available tools and techniques.

■ Increase awareness of the benefits ofimproved material utilisation and theassistance available from Envirowiseand local green business groups.

■ Ensure the benefits of the programmeare communicated fully to all staff.

■ Talk to the Environmental WorkingGroup of Intellect’s Component andManufacturing Services Sector3.

Resources

■ Lack of time and staff to implementa programme to improve materialutilisation.

■ Lack of technical skills andknowledge.

■ Use the support provided by localgreen business groups, Envirowise, etc.

■ Employ external consultants (the cost islikely to be swiftly recouped).

3 Intellect is the new association created to give a single powerful voice for the information technology,telecommunications and electronics industries in the UK. Intellect incorporates members of CSSA and FEI.

Intellect, Russell Square House, 10-12 Russell Square, London WC1B 5EE. Tel: 020 7331 2000. E-mail: info@intellectuk.org Website: www.intellect.uk.org

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Improving laminate utilisation

In many cases, laminate use represents the single largest material cost in PCBmanufacture and accounts for a high proportion of a company’s turnover. More efficientuse of laminate produces significant benefits in terms of:

■ increased profitability;

■ less waste;

■ reduced impact on the environment.

Envirowise research has shown that, by adopting best practice, PCB manufacturers could reducelaminate use by 15 - 35%.

Most PCB manufacturers are aware of the potential benefits of improving laminate use.However, many smaller manufacturers have not yet addressed this issue due to technical,operational and/or time constraints.

4.1 Sources of laminate waste

Laminate is used as the substrate or base for creating PCBs, with all other components beingadded during the manufacturing process. Laminate that is consumed and does not form part ofthe final product becomes waste.

The laminate raw material typically consists of copper-clad, glass-reinforced epoxy resin and ismanufactured in sheets. The laminate is supplied to PCB manufacturers either as sheet or pre-cut to specified panel sizes. Laminate supplied as sheet is cut into standard-sized panels by theboard manufacturer. Any laminate left over after cutting the panels is disposed of as waste.

For multi-layer boards, the laminate raw material consists of copper-clad epoxy resin and compositesandwiched together with copper foil and prepreg (glass felt impregnated with semi-cured resin).Again, the laminate is supplied to PCB manufacturers either as sheets or in pre-cut panel sizes.

The standard-sized panels form the basic starting blocks for PCB manufacture. Board patterns aretransferred onto these panels before a multi-stage process that builds up each pattern intoconductive circuit boards. Depending on the panel size and the number of board patterns laid outon it, several boards (or board layers in multi-layer boards) may be created from an individual panel.

A standard nomenclature is used to define panel sizes. This reflects the warp and weft directioninherent in the glass reinforcement, which in turn has a direct impact upon axial dimensionalstability during bonding. The convention is to quote the warp direction first, eg 18” × 24” is notthe same as 24” × 18” - the former is short warp and the latter is long warp.

DDI Tewkesbury Division has reduced the amount of laminate material it uses by10% over the last two years. However, the company now estimates that, out of thetotal laminate material it currently buys, only 50% is utilised during themanufacture of single-sided boards and as little as 30% for some multi-layer boardswith 12 layers. The company believes that better use of laminate could result infurther savings of approximately 20% in terms of cost and material use.

Savings of 20% from improved laminate use

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At the end of the process, each board is cut (or semi-cut) from the panel to make up thecustomer product and the residual laminate is discarded as waste (see Fig 4). It is fairly commonfor PCB manufacturers to supply customers with a series of semi-routed PCBs on a motherboardtogether with the rest of the laminate panel for final processing. It then becomes theresponsibility of the customer to dispose of any waste laminate.

Ways to reduce waste include:

■ using panel sizes that use the whole sheet of laminate;

■ using panel sizes appropriate for the boards being produced;

■ using larger panel sizes to reduce the percentage of the panel that becomes the toolingmargin (trim).

Techniques to reduce laminate waste are described below.

Waste material is that portionof the manufactured sheet notutilised in the generation ofstandard panels. It is disposedof by either the laminatemanufacturer or the boardmanufacturer.

Waste material is that portionof the panel not containedwithin the circuit boards. Trim is disposed of by either theboard manufacturer or thecustomer.

Laminate raw materialis either supplied in standard panel sizes orcut into such by theboard manufacturer.

Circuit boards or series

Tooling margin

Circuit boards eithercut or semi-cut forsupply to customer

Manufacturing process

The design team selects the mostappropriate size for the paneland determines the best fit forthe circuit boards on the selectedpanel. The tooling margin isalso set.

Fig 4 Laminate utilisation in PCB manufacture

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4.2 Rationalising panel sizes

All PCB manufacturers have their own standard panel sizes. Panelisation is the name given to thedetermination of which standard panel sizes to utilise and the number of different standardpanel sizes deployed by the company.

Panel sizes are subject to a number of constraints, eg:

■ product type;

■ run length;

■ order frequency;

■ manufacturing process;

■ equipment capability;

■ company size;

■ the tooling system being deployed.

Panelisation that is matched to the constraints of an individual situation leads to:

■ simpler stock requirements;

■ faster stock rotation;

■ maximal material use;

■ more efficient use of manufacturing processes and equipment;

■ optimal layout of individual circuit elements.

4.2.1 The benefits of good panelisation

Good panelisation will avoid:

■ the generation of excessive laminate waste after the cutting of the standard size panels (forwhich the board manufacturer will incur a cost penalty);

■ the generation of laminate waste from maintaining stocks of rarely used or unsuitably sizedpanels;

■ the generation of laminate waste via subsequent non-optimisation of board layout;

■ increased unit manufacturing costs by not maximising the capacity or capability of availableproduction processes.

It will also:

■ reduce the frequency of the need to reset cutting machines;

■ improve design turnaround;

■ improve manufacturing turnaround (the panel sizes required are likely to be in stock);

■ reduce stock levels.

Good practice requires regular assessment of panelisation and the changing nature of imposedconstraints. This enables companies to optimise the cost-effectiveness of the manufacturingprocess and to minimise laminate-related waste.

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Panelisation is not a panacea for achieving instant savings. It is one element in obtaining abalance between raw material efficiency, flexibility and process simplicity (resource and labourefficiency).

4.2.2 Quantifying laminate wastage due to panelisation

To measure laminate waste due to panelisation, determine:

■ the loss from manufactured laminate sheets of material not used to make standard sizepanels (either by your supplier or in-house);

■ the stock levels and stock movements of rarely used panel sizes;

■ the levels of laminate waste due to use of a board layout constrained by available panel sizes.

4.3 Improving board layout and reducing trim

This technique involves improving the number and configuration of individual circuit boards ona laminate manufacturing panel. Improving board layout involves making better use of thelaminate material. This can be achieved by:

■ fitting more boards to a panel (ie increasing the packing density);

■ better design and layout;

■ reducing the tooling margin or trim surrounding the sheet to increase the area of availablelaminate.

4.3.1 Benefits of improving board layout

Insufficient attention to optimising board layout will result in excessive laminate waste andreduced manufacturing efficiency. Fig 5 shows the reduction in laminate waste achieved bypacking individual boards more densely.

DDI Tewkesbury Division’s standard panel sizes are now 16” × 12”, 16” × 20” and 18” × 24”, and the company is considering the introduction of 21” × 24” panels toimprove board layout further. According to DDI, this rationalisation has reducedlaminate use by 10% over the past two years.

The panel sizes chosen by DDI are based on an assessment of typical panel sizerequirements in terms of customer orders and process constraints. They alsoconsidered the metrics of the manufacturers’ standard laminate sheet size of 48” ×36”. DDI Tewkesbury Division ensures that less waste is generated at the rawmaterial stage by tessellating its own panel size order to that of the suppliers’standard sheet size. For example, four 18” × 24” or nine 16” × 12” panels can be cutfrom a standard 48” × 36” sheet with no wastage.

Rationalisation of panel sizes reduces laminate use

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Improved board layout also results in significant cost savings. Table 4 gives an example of howsavings can be achieved through increasing the efficiency of board use by modifying board sizeand circuit board layout. Table 4 compares the costs of manufacturing a ten-layer board fromtwo different panel sizes; more circuits per panel are achieved by employing a slightly largerpanel.

Drawing up a table like Table 4 to compare the costs of two board layouts will help you to selectthe most cost-effective layout in terms of laminate utilisation.

The optimisation of board layout increases material utilisation by:

■ Making better use of the laminate material. Covering a greater area of laminate withboards results in less wastage.

■ Improving productivity. The number of boards created from one laminate panel isincreased (it costs the same to process a laminate panel with one board as with ten boards).

■ Increasing process and chemical efficiency. The entire sheet consumes materials andenergy as it goes through the production process. Most ends up being discarded when theboards are cut from the sheet to make the final product. The more of the sheet that is utilisedin boards, the less resources are wasted.

■ Improving processing time. More boards per sheet can shorten production times, resultingin greater product yield and less energy use.

Inefficient Efficient

Fig 5 Examples of efficient and inefficient board layout

Panel A Panel B

Panel size 610 mm × 460 mm 610 mm × 686 mm (24” × 18”) (24” × 27”)

Circuits per panel 2 4

Inner layer cost £16 £23

Biscuit cost £26 £37

Overhead cost £4 £5

Total panel cost £46 £65

Circuit cost £23 £16

Table 4 Example of cost savings from improved board layout

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4.3.2 Quantifying laminate waste due to board layout

To measure laminate wastage due to board layout:

■ quantify the levels of laminate utilisation as:

- an estimate of the percentage per panel processed;

- the cumulative percentage of surface area of manufactured product relative to surfacearea of laminate purchased.

4.4 Summary of best practice

Laminate waste arising from panelisation and board layouts is not two separate issues and it isimportant to address the overall question of laminate utilisation. Table 5 summarises theconstraints affecting improved laminate utilisation, and their solution.

Efficient board layout reduces laminate use

Graphic plc, based in Devon, has made concerted efforts to improve laminateutilisation. The company estimates that it has reduced laminate use by approximately10% by fitting as many individual board elements as possible on a standard laminatepanel (see Fig 6).

Fig 6 Efficient board layout at Graphic plc

Newbury Electronics Ltd uses around 1 500 ft2 of laminate per week during PCBmanufacture. The company has implemented a number of measures to reducelaminate waste. It has:

■ rationalised laminate sheet sizing to a single 24” × 18” size for most applications;

■ improved the board layout of different circuits to maximise laminate utilisation;

■ decreased the trim area from 15 mm to approximately 10 mm all round each sheet.

The company estimates that these measures have improved laminate utilisation by10%.

Fewer means less

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44se

ctio

n

18

Table 6 provides a simple framework for improved laminate utilisation. Optimised panelisationcan improve laminate utilisation by up to 10%, while improvements in board layout andoptimisation of trim areas could generate additional improvements of up to 25%.

Step Actions

■ Quantify the key parameters that define material utilisation.

■ Estimate the potential savings for your company.

■ Review the constraints and variations imposed upon panelisation. These include:- product type;- run length;- order frequency;- manufacturing process;- equipment and tooling capabilities.

■ Working closely with internal design teams and technical departments iscritical in determining the suitability of standard panel sizes, theirspecifications, process conditions and any constraints with design softwareand process equipment.

■ Involving customers wherever possible will help you to:- determine the best size for the ‘job’;- provide them with the information they need to ensure they specify

layouts that make the best use of the sheet sizes and run lengthsavailable from the laminate manufacturer.

However, board designers tend to be driven by form and design, and havelittle involvement in panelisation considerations. Customers themselveshave limited input.

■ In a few cases, the customer specifies the panel size and board layout.Involving such customers in the standardisation programme can help tosecure approval at an early stage as well as capturing useful suggestions.

■ Choose the panel size most suited to the job and which gives:

- the least amount of laminate wastage;- the best packing density for typical customer orders.

■ Review current board layouts and examine new projects to identifyopportunities to increase board density. This can be done when updatingor replacing machinery through the use of digital images (instead of film),rotation, angling and modified spacing of boards.

■ The aim is to optimise the spacing between boards without affectingquality. The ability to reduce the margins between boards is oftendetermined by the capabilities of the design software and the constraintsof manufacturing equipment.

For example, the larger the routing equipment used to cut out the boardsfrom the laminate, the greater the spacing between boards is required.Using the smallest diameter router suitable for the purpose can help toreduce the space between circuits and hence allow a greater density ofboards to be placed on a panel.

■ People to involve in this process include:- designers;- customers;- the technical department;- quality control.

■ Ensure that the new standard panel sizes:- suit most customers;- represent the most effective size to minimise waste and maximise

laminate utilisation.

If necessary, fine tune your choice of sizes.

■ Once the board layout has been optimised, test the boards within theprocess to ensure:- process constraints and equipment are considered;- quality is not affected.

■ Communicate results internally and to customers.

Table 6 Steps to improving laminate utilisation

Assessopportunities

Talk to layoutdesignengineers

Talk tocustomers

Layoutdesign

Panel choice

Trial andapply

55

sect

ion

19

Improving chemical utilisation

The cost of chemicals used in PCB manufacture is the second largest raw material cost afterlaminates. Increasing the efficiency with which chemicals are used within each process stagecan result in significant cost and material savings. This can help to increase your profitabilityand reduce your company’s impact on the environment. An Envirowise study (see section1.2) suggests that savings of over 30% are possible by adopting best practice techniques.

The manufacture of PCBs is a complex process involving a number of stages where chemicals areused for various purposes. These include:

■ chemical cleaning;

■ plating (electrolytic and electroless);

■ materials preparation;

■ etching;

■ stripping;

■ developing.

The best ways of reducing chemical costs in PCB manufacturing are:

■ good housekeeping;

■ reducing waste at source, eg reducing drag-out loss (see box below);

■ improved chemical sourcing (see section 5.1);

■ improved process control (see section 5.2);

■ improved process technology (see section 5.3).

One of the largest sources of chemical waste in PCB manufacture is due to processsolution being ‘dragged-out’ when the board is removed from the process bath. Drag-out and the subsequent contamination of rinse waters is the single largest factorleading to high water consumption and effluent generation in PCB manufacture.

Although some drag-out will always occur, it is important to reduce this losswherever possible as drag-out has costly implications.

■ Chemicals are wasted, thus increasing the bill for raw materials.

■ More water is needed to achieve adequate rinsing performance.

■ Contamination of subsequent process baths diminishes their capability and active life.

■ The additional chemical content of the wastewater increases the treatmentdemand and the cost of operating the effluent treatment plant.

■ More filter cake and sludges are generated and require disposal.

Practical advice on how to reduce drag-out is given in Reducing water and effluentcosts in PCB manufacture (GG303)4. Manufacturers can reduce drag-out loss by up to40% using simple no-cost and low-cost procedures.

The benefits of reducing drag-out from process solutions

4 Available free of charge through the Environment and Energy Helpline on 0800 585794 or via the Envirowisewebsite (www.envirowise.gov.uk).

55se

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5.1 Improved chemical sourcing

Improved chemical sourcing is the specification and purchase of operational chemicals based ontrue cost purchasing. This approach considers purchase cost and all related downstream costssuch as yield, utility demands, disposal/waste treatment demands, environmental issues, etc.

PCB manufacturers typically look at chemical sourcing when:

■ making changes to a product, eg a customer changes surface finish specifications;

■ making changes to the process, eg a new process appears on the market;

■ looking for a new supplier, eg following problems with their current supplier.

While PCB manufacturers may use a number of chemical suppliers, most use only one supplierfor each process stage to ensure that the chemicals used within a stage are compatible with eachother. The chemicals also generally come with a process guarantee from the supplier for theprocess stage concerned.

5.1.1 True cost purchasing approach

Process chemicals are often selected on purchase price alone without considering the benefits ofusing products that are more expensive but have a higher performance. Differences incomposition between process chemistries can have an impact on downstream costs such as:

■ chemical use;

■ solution life;

■ process efficiency;

■ effluent treatment;

■ product quality;

■ energy consumption.

For example, one chemical solution may be cheaper but may require higher operationaltemperatures to achieve the same effect as a more expensive version. When the true fixed costsare included, the cheaper chemical may actually cost more.

The true cost of chemicals is made up of the purchase price plus all downstream costs. Whenmaking purchasing decisions, it is important to consider the true cost rather than just theproduct price.

Another option is to negotiate chemical supply contracts that are charged on the audited levelof board manufacture through a particular process chemistry.

Graphic plc has used a true cost purchasing approach to keep its chemical costs to aminimum. The company estimates that this approach has reduced its chemical costsby 15% over the last three years. Graphic has found that a multi-disciplinary approachis needed to consider all the relevant issues and uses a working group with expertisein all areas of the PCB manufacturing process to make purchasing decisions.

True cost purchasing approach brings savings

55

sect

ion

21

5.1.2 Comparing options

■ Establish a database of true chemical process costs for all stages within the manufacturingprocess. These data will make it easier to make purchasing decisions on a true cost basis.

■ Use the chemical purchasing checklist given in the appendix (and also in the Word documenton the website) to compare similar products from the same or different suppliers. Fig 7 showspart of an example of a completed checklist. Completing the checklist will help you to makepurchasing decisions that will not only save you money, but also reduce the amount ofchemicals required and improve process efficiency.

Key issues include:

- yield;

- maintenance;

- process control;

- environmental, health and safety issues;

- waste treatment and disposal;

- operational conditions;

- equipment demands;

- storage;

- make-up;

- utility consumption.

■ Ask your chemical suppliers to provide the information you need to complete the chemicalpurchasing checklist.

■ You may find it useful to ask a multi-disciplinary team to consider the relevant issues whencompleting the checklist. Possible team members include:

- chemical supplier;

- process manager;

- technical manager;

- financial director;

- health and safety officer;

- environmental manager.

55se

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22

CH

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55

sect

ion

23

5.2 Improved process control

In this section, process control refers to the control and maintenance of the chemical processeswithin a PCB production stage, their ambient operating conditions and the process equipment itself.

Most PCB manufacturers implement a regime of process control, but this is rarely optimised orsubject to regular review. Lack of resources means that chemical testing is performedinfrequently or only when there is an obvious problem. There has also been a trend towardsrelying on suppliers for chemical support. However, a poor regime of process control can lead to:

■ more chemicals being used to produce the desired results;

■ interruptions to the process;

■ reduced life of the process chemicals;

■ increased scrap, eg due to poor deposition of chemicals on the boards.

Improving process control can improve product yields substantially and help to reduce thecompany’s environmental impact. Experience shows that improving process control can result insavings of up to 20% of production costs by preventing inefficient use of materials, eg bypreventing a decline in chemical yields and performance.

The key measurements that determine the effectiveness of chemical control are related to thechemical costs per unit area of board processed. These should be quantified for each processstage and reviewed when changes to control procedures are implemented.

Significant cost savings can be achieved through:

■ measures to extend chemistry life;

■ a programme of planned chemical maintenance;

■ use of statistical process control.

These techniques are discussed below.

5.2.1 Extending chemistry life

Effective chemical control has a significant impact on the life of chemicals in process baths. Thebenefits of extending chemistry life include:

■ more efficient use of chemical purchases;

■ less waste and effluent;

■ improved process efficiency through fewer interruptions.

Interruptions occur when the chemical activity in a bath drops off (either suddenly or over aperiod of time) and the bath no longer performs its required function. A drop-off in activity canbe either prevented or delayed through improved monitoring and analysis, with regular additionsof the correct amount of fresh solution to the process bath. This will result in a more constantlevel of chemical life over a longer period within the bath.

To improve chemistry life:

■ Analyse chemical baths regularly using an appropriate technique.

■ Discard chemicals on an analytical basis and not a time basis (unless stability is an issue orsolution discards must be made at predetermined intervals due to production scheduling).

55se

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24

■ Install/upgrade self-dosing systems on chemical baths. Such systems can be linked to on-linemonitoring systems.

■ Add fresh solution to process baths and remove old solution at a rate such thatcontamination levels never get too high and prevent the solution from working (eg using afeed and bleed system).

■ Prevent cross-contamination between baths by reducing drag-out5.

5.2.2 Planned chemical maintenance

A programme of planned chemical maintenance will help to optimise process control and toensure that chemical use is maintained at optimum conditions. Such programmes should addressthree elements:

■ chemical monitoring requirements;

■ operational monitoring requirements;

■ maintenance of process equipment.

Chemical monitoring requirementsIn consultation with your chemical suppliers, develop a chemical monitoring regime covering theanalysis and maintenance of your process chemistries. This will reduce the risk of:

■ excessive chemical use;

■ unnecessary waste;

■ the generation of scrap board.

Correct analysis can improve chemical yields,particularly when undertaken regularly andnot just when there is a problem. There isalways a risk of a chemical imbalance, but thespeed at which it is detected and addresseddepends on the extent of the controlprocedures in place.

The solutions used in micro-etch chemistry for surface preparation in several processstages are frequently discarded when the level of copper within them becomes toohigh. Regular analysis of the solution and subsequent additions allows the correct levelof copper to be maintained for longer and results in less solution being discarded.

Regular analysis reduces chemical and disposal costs

5 For practical advice, see Reducing water and effluent costs in PCB manufacture (GG303).

Chemical analysis at Graphic plc

55

sect

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25

Operational monitoring requirementsThe use of incorrect or unsuitable operating conditions can have a direct impact on both thenature and rate of the chemical reactions. These in turn affect product quality and waste.

Areas where changes to operating conditions can result in increased wastage of both boards andchemicals include:

■ pH of solutions;

■ ambient temperature (this can affect the rate of the reaction);

■ contact time;

■ probe calibration.

In consultation with your chemical suppliers, establish a programme of regular checks that takesaccount of these parameters and any other operating conditions specific to the process,including the maintenance of monitoring equipment.

Chemical and operational monitoring checklistUse the chemical and operational checklist given in the appendix to help you establish an efficientmonitoring regime. This checklist contains some of the key issues that should be considered withinyour monitoring programme. Fig 8 shows an example of a partially completed checklist.

Maintenance of process equipment Poorly maintained or incorrectly specified process equipment can affect the nature and rate ofchemical reactions or the amount of materials used, eg a small leak from a plating bath or pumpconnection can lead to a loss of around 10 m3/year of solution.

Being out of control is expensive

Process control is a key factor in maximising yield. One PCB manufacturer found thatusing the wrong strength of conditioner during electroless plating of palladiumresulted in approximately three times the normal levels of palladium being deposited.This proved to be an expensive mistake as the cost of the palladium-based catalystchemistry represented between 5% and 10% of the total process chemistry costs.

Proper monitoring and control at this company would have reduced:

■ the amount and cost of palladium-based chemicals used;

■ the generation of scrap board (discarded because of grainy deposition and pooradhesion);

■ chemical waste leading to instability of the electroless copper bath and potentialbath exhaustion.

CHEMICAL AND OPERATIONAL MONITORING CHECKLIST

Issue

Amount of workbeing processed

ProcedurereferenceFrequency Responsibility CommentsParameter

Daily P1.3Number ofboards

Processmanager

Results recordedin D:/work.xls

Fig 8 Example chemical and operational monitoring checklist

55se

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26

■ In consultation with your plant and equipment suppliers, establish a programme to ensureoptimum performance of process equipment. This programme should include preventativemaintenance, upgrading, monitoring and the use of statistical-based techniques. This mayinvolve:

- monitoring automatic dosing equipment;

- regular cleaning of rollers on horizontal lines;

- regular cleaning of electrodes on equipment with electrical connections.

Developing your chemical maintenance programmeOnce you have devised appropriate monitoring and equipment maintenance programmes:

■ establish a supporting system of procedures and records to ensure that planned monitoringand any associated corrective actions are carried out correctly;

■ review your monitoring and analysis programmes periodically and to take account of:

- performance issues;

- changes to chemicals or process;

- changes to suppliers;

- changes to products.

5.2.3 Statistical process control

An alternative to a formal monitoring programme is the installation of a real-time monitoringsystem such as statistical process control (SPC). SPC is a way of monitoring a process during itsoperation in order to control the quality of product during production. It provides an alternative topost-production inspection, which is useful but can only identify problems after they have occurred.

SPC involves gathering information about the product, or the process itself, on a near real-time basisso that the operator can take action while the process is on-going. This allows the causes of variationand other abnormal processing conditions to be identified, thus bringing the process under statisticalcontrol and reducing variation. Fig 9 shows SPC software being used at Graphic plc.

Fig 9 SPC in use at Graphic plc

55

sect

ion

27

The high number of variables with a potential impact on production performance makes SPCparticularly applicable to the chemical processes during PCB manufacture. Unless the process isautomated, however, it may take some time to collect the required data due to the high numberof parameters to be measured.

SPC is not necessarily a simple alternative to formal monitoring. In some cases, chemical suppliersthat charge by the area of board treated can provide continuous monitoring systems to enableprocesses to run more efficiently. You should explore this option directly with your suppliers.

The benefits that can be achieved through implementing SPC include:

■ better quality control and maintenance of the process resulting in good quality products andfewer rejects;

■ more efficient use of raw materials;

■ maintenance of optimum operating conditions (eg temperature and pH);

■ ability to identify problems before the product run is completed;

■ less waste;

■ cost savings.

Factors to consider with SPC include:

■ the need for operator training;

■ the time and resources necessary to set up SPC within the process and to run trials tooptimise operating conditions;

■ the cost of any software/training;

■ the long-term rather than the short-term benefits.

Further information on SPC is given in Preventing waste in production: practical methods forprocess control (GG224) and Preventing waste in production: industry examples (GG223). BothGuides are available free of charge through the Environment and Energy Helpline on 0800585794 or via the Envirowise website (www.envirowise.gov.uk).

5.3 Improved process technology

New and alternative process technologies are available that can be installed at little or no costusing existing plant and equipment. Before deciding to adopt any improved process technology,it is important to carry out trials in conjunction with chemical and process plant suppliers in orderto assess its capability, quality, true chemical cost and capital cost.

5.3.1 Alternative oxide process system (AOPS)

The AOPS process is an example of an improved process technology which is fast emerging asbest practice.

An oxide conversion process is used within the manufacture of multi-layer circuit boards toprepare the copper inner layers of the board prior to bonding. This conversion process involvessemi-cured resin, heat and pressure. The oxidised copper surface provides a rough surface andresistance to thermal oxidation, which give a high degree of adhesion between layers.

Until recently, oxide conversion has been commonly carried out using a black oxide techniqueinvolving a five-bath immersion and rinsing process. As shown in Fig 10 overleaf, the AOPSrequires fewer baths and less rinsing.

55se

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28

The benefits of AOPS compared with the conventional black oxide process include:

■ lower initial purchasing costs;

■ material and cost savings (there are fewer process stages);

■ use of hazardous chemicals is eliminated or reduced;

■ reduced water consumption (there is less demand for rinsing);

■ reduced waste/effluent requiring treatment;

■ improved process efficiency;

■ can be used within conveyor equipment for continuous operation.

Acid cleaner

Black oxide process

Rinse

Cleaner

Alternative oxide process system

Rinse

Activator

Rinse

Alternative oxide

Rinse

Micro-etch

Rinse

Pre-dip

Black oxide

Rinse

Reducer

Rinse

Fig 10 Comparison of black oxide process and AOPS

Graphic plc is a high-technology multi-layer PCB board manufacturer. In 1999, thecompany replaced its black oxide process with an AOPS. In 2001, it then replaced itsvertical AOPS line with a horizontal AOPS line (see Fig 11), and overall has seen areduction in inner layer chemical costs of about 60%.

AOPS reduces inner layer chemical costs

Fig 11 Alternative oxide process system at Graphic plc

55

sect

ion

29

Installation of an AOPS is relatively straightforward. It should be undertaken in conjunction withyour chemical supplier, who can advise on equipment, deployment and other related issues suchas chemical control, waste treatment, etc.

Considerations to bear in mind with AOPS:

■ some second generation AOPSs have a low tolerance to chloride ions and may require goodquality demineralised water;

■ electrolytic recovery of copper from spent chemistry may require special procedures.

Further information should be sought from your chemical suppliers.

5.3.2 Eductors

An alternative to using air agitation (eg to ensure thorough solution movement within a copperelectroplating bath) is to consider a pumped agitation system using eductors. These give a highvelocity stream of solution.

The benefits of eductors include:

■ reduced consumption of organic addition agent within the electrolyte;

■ improved solution management;

■ shorter plating times (related to the improved throwing power).

The cost of fitting eductors is relatively low at approximately £1 500 per line. Further informationon the costs and benefits of fitting pumped eductor-based agitation systems should be soughtfrom suppliers of this type of equipment.

5.3.3 Feed and bleed systems

Feed and bleed systems involve a constant feed of the process chemistry into a process bath,balanced by a constant bleed from the tank through an overflow (see Fig 12). In this way, thechemistry is replenished at the same rate at which it is depleted. This results in a constant flowof ‘fresh’ solution through the bath.

Option Technologies Ltd operates a ‘mass lamination’ facility and, as such, does notproduce a final board product but instead generates inner and outer layers throughto the multi-layer lamination stage for supply to other board manufacturers andoriginal equipment manufacturers (OEMs). Installation of a first generationalternative oxide conveyor line has reduced inner layer chemical costs from about£1.00/m2 to about £0.35/m2.

AOPS reduces chemical costs per square metre by 65%

Process

Feed

Bleed(overflow)

Fig 12 Schematic diagram of a feed and bleed system

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Applications for feed and bleed systems (see Fig 13) in PCB manufacturing include volumechemistries such as etchants, electroless solutions and developers. Feed and bleed systems allowa high degree of process control; the narrower the operating parameters (or process window),the more value is likely to be gained.

Feed and bleed systems do not involve significant capital cost. However, the specific flow regimehas to be established for individual applications.

Feed and bleed systems can be automated by linking dosing systems to monitoring mechanismssuch as pH probes; the volume of process solution flow can be either increased or decreaseddepending on the probe reading and the parameters set.

When determining the suitability of installing a feed and bleed system within a process line, it isimportant to be aware of all the operating parameters affecting the solution. Chemical suppliersshould be able to provide this information and some have been known to supply feed and bleedsystems free of charge.

5.3.4 Adopting an improved process technology

■ Assess the quality, capability and chemical cost (remembering to take account of any relatedor downstream costs) of the technology.

Fig 13 Feed and bleed dosing system at Graphic plc

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■ Discuss and assess the technology in conjunction with your chemical suppliers.

■ Discuss equipment requirements with your chemical suppliers and equipment manufacturers.

■ Evaluate boards produced using the technology in trials carried out either at your suppliers’premises or in-house.

5.4 Summary of best practice

Table 7 provides a simple framework for improved chemical utilisation. Research has shown thatcompanies can reduce their annual chemical consumption by over 35% by adopting bestpractice techniques.

Step Actions

Assess ■ Compile a process flow diagram of your manufacturing process showingopportunities the main operations, materials consumed and waste produced. Depending

on material costs, those stages that consume the greatest quantities ofmaterials and/or produce the greatest quantity of waste typically give thequickest cost and material savings.

■ Estimate the potential savings for your company.

■ Use this Guide and Reducing water and effluent costs in PCB manufacture(GG303) to identify potential improvement measures.

Improve ■ Establish a database of true chemical process costs for all stages within thechemical manufacturing process. This will make it easier to make purchasingsourcing decisions on a true cost basis.

■ Consult your chemical suppliers.

■ Use a checklist like the one in the appendix to help you calculate the truechemical costs. Include:

- yield;- maintenance and control;- environmental, health and safety issues;- waste treatment and disposal;- operational conditions;- equipment demands;- storage;- make-up;- utility consumption.

Improve ■ Draw up a comprehensive chemical and operational monitoring regime (inchemical consultation with your chemical and equipment suppliers).control ■ Draw up a planned maintenance programme (in consultation with your

plant and equipment suppliers).

■ Establish a system of procedures and records to ensure that plannedmonitoring and any associated corrective actions are carried out.

■ Review your monitoring and analysis programmes periodically andwhenever there are performance issues or changes to chemicals, processes,suppliers or products.

Consider ■ Discuss and assess all potentially beneficial chemical processes and processes and technologies in conjunction with chemical, equipment and plant suppliers.technologies ■ Evaluate boards produced during trials with the improved process

technology.

Trial and ■ Implement opportunities to improve chemical utilisation.apply

Table 7 Steps to improving chemical utilisation

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Reducing drill costs

6.1 Drill bit regrinding

Drills are used in PCB manufacture to create holes in the laminate boards. These holes bringabout inner layer connections and permit subsequent mounting of components with solder.

Tungsten carbide drill bits are traditionally used to drill holes through the layers of laminate. Thesurfaces of the holes are then rendered conductive and electroplated to provide inter-layerconductivity within the board components. Up to 30 000 holes per circuit board can beobtained using an automated drilling machine. The process of drilling eventually blunts the drillbit and, depending on the substrate, necessitates each drill bit being changed afterapproximately 2 000 - 3 000 holes.

Most PCB manufacturers regrind drill bits, but many smaller companies do not regrind or limitregrinding. This is usually due to a fear of regrinds affecting hole quality and integrity, or a lackof awareness of the financial benefits of regrinding.

6.1.1 The cost benefits of regrinding

The high number of drill bits used in the creation of a PCB means that significant cost andmaterial savings can be achieved by regrinding worn drill bits and using these regrinds insteadof new drill bits.

Regrinding results in drill bits of a similar quality and performance to new ones. The cost ofregrinding a drill bit can be up to 80% less than the cost of a new drill bit. Table 8 indicates thescope of cost savings from regrinding drill bits.

Number of regrinds Cost savings

1 40% of total monthly cost of drill bits2 55% of total monthly cost of drill bits

Table 8 Potential monthly savings from regrinding drill bits

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6.1.2 Optimising drill bit use

The cost per finite number of holes drilled gives an indication of the optimisation of drillutilisation. This can be measured by combining:

■ the number of holes made per regrind;

■ the number of regrinds per drill.

Regrinding reduces costs by 55%

Graphic plc estimates that it saves up to £150 000/year on drill costs throughregrinding.

Graphic has investigated the number of times a drill bit can be used before thewear on the drill bit starts to affect its ability to be reground. For most types oflaminate board, this number is around 2 500 - 3 000 - although this can be lowerif denser board is used. Graphic uses X-ray imaging (see Fig 14) along withmicrosection analysis and scanning electron microscopy (SEM) to examine thequality of the holes made in boards.

Fig 14 Examining the quality of drill holes at Graphic plc

Graphic has found that two is the optimum number of regrinds for its business. Athigher regrind frequencies, Graphic found that some drill bits became too short tobe used and that productivity was affected by more drill bits failing on the machine.

The company that performs the regrinding operation for Graphic colour codes thedrills so that regrinds are easily identifiable. Drill bits that have been reground onceare marked with red and those reground twice are marked with blue. This colour-coding system enables Graphic to manage its drill bits efficiently and ensures that theyare not sent for regrinding more than twice. The reground drill bits cost around 20%of the cost of a new drill, thus allowing Graphic to save around 55% on drill bit costs.

Recycling the used tungsten carbide drill bits costs the company nothing and bringsin revenue of about £450/year.

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These two parameters can be established through a quality evaluation programme carried out ontest panels and by considering parameters such as feed and speed, chip size and stack heights.

The main factor limiting the number of regrinds possible for each drill is the length of the drillbit, which is reduced through wear and the regrinding process. Companies typically regrind twoor three times, although four or even five times can be possible before final disposal. It is moreefficient to limit the number of holes drilled by each drill so that they do not become excessivelyworn. This is because drills that are excessively worn are less suitable for regrinding and are morelikely to break before being sent away. The optimum number of holes to be drilled varies withthe quality of the laminate being drilled, but is likely to be between 2 000 and 3 000.

6.2 Other opportunities

Other opportunities for making savings within the drilling process include:

■ Using melamine-faced backing plates in drill assemblies twice before disposal (ie using theirreverse side).

■ Recycling single-facing backing boards.

■ Investing in laser drilling (thus eliminating the need for tungsten carbide drills). This currentlyrequires a high level of investment but, as the technology becomes more widely available, itis likely to become more cost-effective and popular.

6.3 Summary of best practice

Table 9 provides a simple framework for optimised drill bit utilisation.

Step Actions

■ Determine the total cost of drill bits and how much waste is produced.

■ Compare costs with using regrinds. You can expect regrinds to be 60 -80% cheaper than new purchases.

■ Identify a company offering a regrind service. Talk to your drill bitsupplier.

■ Inspect drills to determine how many holes can be drilled before theystart to become obviously worn. Once you have a rough figure for this,use trial and error to determine the optimum number.

■ Send a batch of drill bits that have been used for the optimum numberof times to the regrind company.

■ Trial regrinds on low value boards within the process to ensure:

- process/equipment constraints are considered;- there is no adverse effect on quality.

■ Set up a quality inspection system for boards using regrinds. This mayonly need to be a temporary measure until you are confident aboutproduct quality when using regrinds.

■ Establish the optimum number of times that drill bits can be regroundand develop a regrind policy within the company.

■ Develop a colour-coded system with the regrind company to identifyhow many times each drill bit has been reground. Once a system is inplace, formalise it into a procedure.

■ Collect tungsten carbide drill bits that are broken or cannot be regroundagain and send them for recycling.

Table 9 Steps to improving drill bit utilisation

Identifypotential costsavings

Identify aregrind company

Inspect drills

Trial regrinds onlow value boards

Set up inspectionsystem forregrinds

Trial number ofregrinds

Establish aregrind systemand procedure

Recycle spentdrill bits

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Action plan

The industry examples in this Guide demonstrate the significant savings in costs andmaterials that can be achieved by companies that take action to improve their materialutilisation. Table 10 provides an action plan to help you maximise cost savings byimproving your material utilisation.

Area Action

✓ Draw up a process flow diagram for your manufacturingprocess.

✓ Identify the inputs and outputs for each process stage.

✓ Calculate the true cost of waste to your company.

✓ Determine the scope for savings from using materials moreefficiently.

✓ Find out why waste is produced.

✓ Evaluate opportunities to reduce raw material use and waste.Remember to adopt a systematic approach and to follow thewaste hierarchy (see section 1.4).

✓ If you employ fewer than 250 people, contact the Environmentand Energy Helpline on 0800 585794 and ask about FastTrackvisits. These are confidential, on-site waste reviews that includeup to a day’s free advice on resource efficiency from anenvironmental expert.

✓ Gain senior management commitment.

✓ Set up a waste minimisation team with representatives from alldepartments.

✓ Increase staff awareness of waste and the benefits of improvedmaterial utilisation.

✓ Communicate ideas and results to all staff.

✓ Make use of the free support available from Envirowise (seesection 7.1).

✓ Identify sources of laminate waste.

✓ Review the constraints and variations affecting panel sizes.

✓ Rationalise panel sizes (see section 4.2).

✓ Improve board layout (see section 4.3).

✓ Assess opportunities for improvement and identify potentialcost savings.

✓ Adopt good housekeeping measures.

✓ Reduce drag-out loss (see section 4 of Reducing water andeffluent costs in PCB manufacture (GG303)).

✓ Adopt a true cost purchasing approach (see section 5.1.1).

✓ Improve process control by:

- implementing measures to extend chemistry life (see section5.2.1);

- undertaking a programme of planned chemical maintenanceincluding regular analysis, chemical monitoring, operationalmonitoring and maintenance of process equipment (seesection 5.2.2);

- using statistical process control (see section 5.2.3).

✓ Adopting improved process technologies such as AOPS, eductorsand feed and bleed systems (see section 5.3).

Table 10 Checklist of actions to improve your material utilisation

How can you identifysavings opportunities(see section 2)?

How can you overcomebarriers to improvedmaterial utilisation (seesection 3)?

How can you improvelaminate utilisation(see section 4)?

How can you improvechemical utilisation(see section 5)?

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7.1 Help from Envirowise

Envirowise offers a range of free services including:

■ advice from Envirowise experts through the Environment and Energy Helpline on resourceefficiency, cleaner technology, waste minimisation, environmental issues and environmentallegislation;

■ a variety of publications that provide up-to-date information on waste minimisation issues,methods and successes;

■ on-site reviews (a FastTrack visit) from an independent Envirowise advisor to identifyopportunities for reducing waste6;

■ best practice seminars and practical workshops that offer an ideal way to examine wasteminimisation issues and learn about ways of reducing waste;

■ guidance on waste minimisation clubs and other partnerships across the UK that provide achance for companies to share best practice on waste minimisation.

To contact Envirowise:

■ phone the Environment and Energy Helpline on freephone 0800 585794;

■ send an e-mail to helpline@envirowise.gov.uk;

■ visit the Envirowise website (www.envirowise.gov.uk).

7.1.1 Useful Envirowise publications

All Envirowise publications are available free of charge through the Environment and EnergyHelpline on freephone 0800 585794 or via the Envirowise website (www.envirowise.gov.uk).

Relevant Envirowise publications include:

■ Reducing water and effluent costs in PCB manufacture (GG303)

■ Benchmarking water use in PCB manufacturing (BG279)

■ Copper recovery cuts costs and waste (CS286) - a Case Study at APW Electronics Ltd

■ Lead-free solder: the issues (EN287)

■ Support for electronics manufacturers (EN379)

■ Preventing waste in production: practical methods for process control (GG224)

■ Preventing waste in production: industry examples (GG223)

Area Action

✓ Identify potential cost savings by comparing cost of new drill bitswith cost of using regrinds.

✓ Establish optimum number of holes that can be drilled per bitand number of times drill bits can be reground.

✓ Carry out trials with regrinds.

✓ Develop a regrind policy.

✓ Recycle tungsten carbide drill bits.

Table 10 Checklist of actions to improve your material utilisation (continued)

How can you improvedrill utilisation (seesection 6)?

6 Available if you employ fewer than 250 people.

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■ WasteWise: increased profits at your fingertips (IT313) - interactive waste minimisation CD-ROM

■ Finding hidden profit - 200 tips for reducing waste (EN30)

■ Cutting costs by reducing waste: a self-help guide for growing businesses (GG38C)

■ Saving money through waste minimisation: teams and champions (GG27)

■ Waste minimisation pays: five business reasons for reducing waste (GG125)

■ Green officiency: running a cost-effective, environmentally aware office (GG256)

■ Finding hidden profit for smaller companies (GG253)

■ Cost-effective water saving devices and practices (GG67)

■ Tracking water use to cut costs (GG152)

■ Choosing cost-effective pollution control (GG109)

■ Electronic equipment manufacturer benefits from cleaner design (NC201) - a Case Study atVarian Medical Systems UK Ltd

■ Minimising chemical and water waste in the metal finishing industry (GG160)

■ Over £1 million of efficiency savings achieved by an electroplating company (CS385) - a CaseStudy at Frost Electroplating

■ Solder and cost recovery from dross (CS319) - a Case Study at Stadium Electronic ControlsDivision

app

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38

Worksheets and checklists

Please photocopy these worksheets and checklists for use in your company:

■ Waste record sheet;

■ Chemical purchasing checklist;

■ Chemical and operational monitoring checklist.

Electronic versions of these tools can be downloaded as a Microsoft® Word file from theEnvirowise website (www.envirowise.gov.uk). Look for ‘tool’ on the page devoted to thisGuide in the Publications area of the website.

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Envirowise - Practical Environmental Advice for Business - is a Government programmethat offers free, independent and practical advice to UK businesses to reduce waste atsource and increase profits. It is managed by Momenta, an operating division of AEATechnology plc, and Technology Transfer and Innovation Ltd.

Envirowise offers a range of free services including:

Free advice from Envirowise experts through the Environment and EnergyHelpline.

A variety of publications that provide up-to-date information on wasteminimisation issues, methods and successes.

Free, on-site waste reviews from Envirowise advisors, called FastTrack visits, thathelp businesses identify and realise savings.

Guidance on waste minimisation clubs across the UK that provide a chance forlocal companies to meet regularly and share best practices in waste minimisation.

Best practice seminars and practical workshops that offer an ideal way toexamine waste minimisation issues and discuss opportunities and methodologies.

For further informationplease contact the

Environmentand EnergyHelpline0800 585794© Crown copyright. First printed August 2003. Printed on paper containing a minimum of 75% post-consumer waste.

This material may be freely reproduced in its original form except for sale or advertising purposes.

Harwell International Business Centre | Didcot | Oxfordshire | OX11 0QJE-mail: helpline@envirowise.gov.uk Internet: www.envirowise.gov.uk

Practical Environmental Advice for Business