Look on NCAB’s technicians as a resource to draw on during your development work. We have extensive experience and considerable reserves of knowledge of what is right – and not so right – in PCB design and production.

 

Does IPC Class 3 promote reliability?

The problem is that PCBs are seldom sold at the right price and that customers don't always get what they ordered. Either due to tradition or routine, plus a large dose of customer ignorance, PCBs are frequently ordered using specifications with very high reliability, e.g. IPC Class 3 – at a price that doesn't cover the costs! The PCB supplier accepts the order for the same reasons, but without delivering the desired reliability, and consequently at the wrong price.
We are living in a world of illusion. The customer believes, or wants to believe, that he is getting the right product. And the supplier also believes he is supplying the right product.

Why is this? What can we do? And how much should reliability cost? Read more about this highly topical issue in our newsletter. 

Recommendation for baking of Flex and Rigid-Flex PCBs

Due to the fact that nearly all Flex and Rigid-Flex boards are constructed with polyimide inside and that the polyimide is highly hydroscopic in its form, it is strongly recommended to bake the boards to reduce the amount of moisture inside the boards before any type of soldering operation can take place, otherwise there is big risk of delaminating, broken innerlayer connections or cracked hole walls.

Download the recommendation here:
Recommendation for baking of Flex and Rigid-Flex PCBs 

Standardisation assures quality in an industry with rapid development

Have you found your products don't work? That your products are returned after a while in the field? That their solderability is not up to standard? That the products contain faults that are hard to define and need further analysis? Or, quite simply – that the product you have chosen doesn't live up to your expectations?
Those are just some of the problems that may occur when relevant standards have been disregarded in the production process. NCAB uses IPC – a comprehensive set of standards for the electronics industry.

NCAB's quality assurance through standards
All of NCAB's offices are members of the IPC which, combined with our quality assurance work, provides customers with these advantages:
• NCAB ensures that PCBs are produced according to the latest standards.
• We reinforce our quality assurance work with full membership.
• NCAB's membership means that customers have an indirect influence on how the standards are developed.
• Communication is more effective in all areas due to standardised language being used.
• Any complaints are managed efficiently, as the fault analysis can be rapidly deduced through IPC.
• Standards clarify customer requirements, assuring the right quality level. Even if customers do not refer to a standard, NCAB ensures that the PCB is manufactured according to the most suitable IPC standard.

Read more about standardization, problems and solutions in our newsletter!

 

Effective water purification – towards more environmentally-friendly PCB manufacture

It is a fact that the process of manufacturing PCBs has a great impact on the environment. At NCAB we want to do everything we can to reduce environmental impact as much as possible. Since our main suppliers are in China we wish to be particularly clear about how environmental work is carried out there. See our newsletter issue 4-2007 for more information.

What we can and want to do
NCAB works actively on environmental improvements. We critically review every supplier's environmental programme and participate in discussions aimed at creating a better environment. NCAB has long required that all of our suppliers must be ISO14000 certified or have a set time-plan for when they will receive certification. As reducing energy and water consumption directly benefits the environment, NCAB has recommended these parameters to our suppliers as environmental targets. We help our suppliers to establish realistic environmental targets that we then follow up in our ongoing audits, as we also check the monthly reports from the environmental authorities.

 

PCB cleanliness

Why do you need to worry about the PCB’s cleanliness? Haven’t we assembled electronics for over 100 years and shouldn’t cleaning equipment and new materials have developed during this time, making PCBs cleaner than ever before? Of course this is the case. However, there is cause for some concern and raised consciousness. Now that we almost exclusively use either “no-clean” or water-washable fluxes with very low mass ratios there is an increased risk of residue on the PCB.

Add to this the smaller components being developed by the component industry, that can be mounted even closer together, and the increasing complexity of PCBs with denser configurations and reduced insulation distances. All that combined has led to an increase in field failures in the form of such faults as unwanted drops in voltage, short circuits in the form of migration between components and solderability problems.

Read more in our newsletter how what causes metallic migration and where the contaminants come from.

What factors determine the price of a PCB? 

There are a number of factors that affect the price of a PCB – e.g. the size, lead time, number of PCBs, choice of materials, number of layers, number of drill & press cycles, restricted tolerances and correct or incorrect advice. In this newsletter, we at NCAB want to shed some light on these factors and provide you with information that will improve your purchasing. This Newsletter looks at the three most important factors.

Well-intended advice may increase production costs
Is there a risk that advice provided with the best of intentions actually increases the price of a PCB? Shouldn’t all advice be beneficial? Naturally, the aim of advice is to provide the customer with better results from their purchasing, but problems can occur when the advice is given at an early stage of the design process – e.g. when developing the prototype. Advice about production tolerances, specific make of laminate, choice of prepreg, etc may then be affected by the prototype manufacturer’s sometimes very limited experience of large volume production.. This advice often only takes into account what the prototype manufacturer has in the way of standard materials, surface finishes, internal layers, cores and production equipment.

Example:
As a general rule, the prototype manufacturer’s greatest cost incentive is the lead time. When a complicated design arrives he can always choose to start production on several PCBs. It is often of lesser importance for the prototype manufacturer if he starts production of 20 PCBs and then only delivers 10 to the customer, but this equation becomes impossible when it comes to large volume production, where the basis is a final outcome of 95-98%. The prototype manufacturer’s advice may therefore result in a product which can be very difficult and expensive to produce in larger volumes, purely due to a lack of knowledge about large volume production. 

Read more in our newsletter how the correct advice, right choice of materials and tolerances can give you improved PCB production economy.

IMS – effective technology for heat dissipation

New opportunities with Insulated Metal Substrate
For greater amounts of energy or local thermal loads, e.g. in modern constructions with high intensity LEDs, IMS technology can be used. The abbreviation, IMS, stands for “Insulated Metal Substrate”. This is a PCB built on a metal plate – normally aluminium – on which a copper foil has been attached with a special prepreg, the primary qualities of which are an excellent capacity for heat dissipation and great dielectric strength against high voltages. Together with EBV and a number of other companies, NCAB has taken part in the development of a demo product. The aim here is to attract the market’s attention to the opportunities for combining high intensity LEDs with IMS technology.

The most important constituent – the heat-conducting prepreg – is a ceramic or boron-filled material, specially produced to be able to dissipate large amounts of heat. Its heat conductivity is often 8-12 times greater than that of an FR4. Some well-known manufacturers of these materials are Bergquist and Laird Technologies.

Bergquist
The Bergquist Company is the world leader in the development and manufacture of thermally conductive interface materials. Thermal Clad Insulated Metal Substrate (IMS®) was developed by Bergquist as a thermal management solution for today's higher watt-density surface mount applications where die size is reduced and heat issues are a major concern. Read more about the advantages with Thermal Clad and design rules.

Thermagon Laird Technologies
Laird Technologies is the world’s leading designer and manufacturer of thermally conductive interface materials for electronical constructions. Read more about advantages and characteristics of these termal materials.

The advantages of IMS PCBs for heat dissipation
An IMS PCB can be designed with a very low thermal resistance in comparison to an FR4. Since the thermal prepreg or epoxy layer is very thin, the thermal resistance is also low. If, for example, you compare a 1.60 mm FR4 PCB to an IMS PCB with a 0.15 mm thermal prepreg, you may well find the thermal resistance is more than 100 times that of the FR4 PCB. In the FR4 product it would be very difficult to dissipate any large amount of heat.

Another solution is to combine the FR4 material with vias, for example, which are plugged with thermally conductive paste, giving the PCB better thermal qualities than normal. This is often a more cost-effective solution, as traditional FR4 technology is used.

If you would like to know more about techniques for heat dissipation, please contact Kenneth Jonsson, kj@ncab.se or Bo Andersson, ba@ncab.se 

Flex-Rigid PCBs put higher demands on manufacturers

Many PCB producers manufacture flex-rigid PCBs in a way that cuts production costs, but sacrifices quality assurance. NCAB has in recent years evaluated several manufacturers of this type of board. We found many of the boards evaluated of a sub-standard quality. This indicates a considerable lack of know-how among producers of flex-rigid PCBs, both in the Far East and in Europe.

Sub-standard manufacture leads to considerable flaws
The biggest flaws in these boards have been shown to stem from a sub-standard manufacturing approach. In our evaluation we used two sets of artwork with limited specifications, where basically all that was specified were the materials to be used in the flexible and rigid parts respectively. Read more about the result in our newsletter: Flex-rigid PCBs put higher demands on manufacturers!

Let us improve your product
NCAB would be very happy to assist you, at the early manufacturing stage, with advice regarding choice of material, manufacturing and design guidelines.

If you are interested in learning more about this subject, NCAB's engineers are available for an appropriate course of instruction at your premises. Please contact our sales personnel for more information about these types of courses.