NPL Soldering Defects Database

NPL Defects Database

The Soldering Defect Database is a freely accessible resource from the National Physics Laboratory website:

Defects Database

This little known resource is a fully searchable database of soldering defects with pictures, and information about the causes and solutions of each problem. Once signed up not only is all the information available but the database can be added to with any findings a user wishes to add.

This is a truly a brilliant resource and I can’t think of how many occasions this could have been of use in the past. Have a look, get involved and make sure to pass it onto your colleagues.

Circuit Mechanix Apr-2017


The PCB Mechanic – The UK PCB industry and facing the challenges of the future

PCB Mechanic


PCB fabricators in the UK are facing the challenges of being able to make the PCB’s that the designers need to accommodate these modern packages. This is no easy challenge, fabricators based in Asia and other European countries are providing their customers with advanced capabilities that not long ago were not possible. Not only do these fabricators have the capability, but the manufacturing costs cannot be matched equivalent fabricators in the UK.

Electronics are advancing at an ever increasing rate and this rate has no sign of abating. Integrated circuits are being developed all the time with increasing speeds, functionality and higher densities than were available before.
This gives engineers the components they need to create products with more functionality in a much smaller form factor than has been possible before. No other market shows more evidence of this than the smart phone and tablet market. These supercomputers in our pockets were inconceivable in such a compact size fifteen years ago.

Chip packages come with far more, smaller connections, whether they’re balls, pads or pins in a much more compact package. In for UK fabricators to win business to serve this insatiable demand for smaller and better electronics, they need to be able make the boards that are being designed today and be looking forward to the designs needed in the years to come. It doesn’t seem that long ago that a track and gap of less than 0.2mm would be the exception rather than the norm, but modern electronics has ended this forever.

It seems however that many UK fabricators are struggling to realise this and are not investing enough to keep up with the rate of change.

The high density PCB packages of today are forcing designers to use track and gaps of less than 0.1mm or copper filed via in pad, or via sizes of 0.1mm just to be able to route connections out to the rest of the circuit. BGA’s aren’t the only issue, dual row and other leadless packages where the pins are 0.5mm apart or less are forcing designers to make tough choices about where they place the compromise in their designs.

BGA’s aren’t the only issue, dual row and other leadless packages where the pins are 0.5mm apart or less are forcing designers to make tough choices about where they place the compromise in their designs.

There aren’t many PCB fabricators left in the UK and only a handful are able to compete with the capabilities that offshore companies are able to give. The reality is that there is a tough job ahead to catch up and keep up and many PCB fabricators haven’t advanced their capabilities in over 10 years. This is an age in technology terms. The UK cannot possibly compete on cost with offshore manufacturing, but if they can’t do at least the same or better, there is no way to compete with the offshore fabricators.

Simon Farnell The PCB Mechanic

This article was features in the March ‘What’s new in Electronics’ newsletter:

Flexi PCB’s and making something wobbly like it’s not

Just like standard rigid PCB’s flexi’s and flex rigid PCB’s have to have components assembled onto them to make them useful in a circuit. However unlike rigid PCB’s flexi’s are well… flexible.

The flexible nature of a flexi is it’s strength in the field, but during manufacture causes nothing but problems! There are ways and means around this and that’s what’s going to be discussed here.

Part of the issue is that the fabricator needs to make the FPCB’s on a rigid panel that the assembler can accept and work with. In prototyping volumes this isn’t likely to be an issue, but if thousands or millions of FPB’s are to be made then there has to be a solid working interface between the fabricator and assembler to make it work optimally.

PCB’s are usually more efficient to assemble in larger volumes on a panel. Flex panels tend to have less circuits on them and a smaller as the panel, even with stiffeners are often weaker. If there are components on both side of an FPCB, then making the panel so that solder paste can be deposited onto the board also needs considering. Often stiffeners or panels sit above the FPCB, making paste deposition impossible. It’s for this reason that good communication is needed between designer and fabricator to get every detail right

Be warned – making a the same design in different companies can result in different approaches and things going wrong. Because there is so much more for the manufacturer to understand than rigid PCB’s like stiffeners, panels etc, there is more to get wrong.

Layer stackups are also something to watch out for, especially between different fabricators and sometimes different factories within the same company. The differences are often very minor and irrelevant but even small differences can have an effect on a design – especially in high speed circuits.

Good fabricators will highlight these changes and give their best alternative so keeping track of what’s being built can be done.

The nightmare every PCB designer needs to consider in FPCB’s is how any components will be assembled onto the board. If the flexi is on a panel this is a good first step, areas where components need to be assembled onto them will need to be secured or assembly will be impossible.

Fabricators will have tape or some other kind of way to secure
Component area’s on FPCB’s. Identify these area’s in the output data and label them to make it easier for the fabricator to identify these areas and process them accordingly. Doing this will make assembly far easier – the only problem after this might be peeling the flexi away from the panel without damaging the components or their solder joints.

It’s for this reason that assembling components onto FPCB’s should only be done when it absolutely has to be done.

If you’re not putt off yet, you should be – no one said it would be easy!

Circuit Mechanix © 2016