Month: December 2018

Manufacturing electronics for hostile and hazardous environments

by

Why your EMS partner is your best friend for extreme environments

John Johnson, NPI Director, Chemigraphic

We all rely on electronic products

Imagine your life without your smartphone and you’ll realise just how much we all depend on our electronic products these days.

And – shock, horror! – if you’ve ever had the misfortune to watch your beloved mobile slip into a sink full of soapy water or drop into a pan of hot gravy, you’ll be painfully aware that electronics and harsh conditions do not mix well.

Those intricate electronic circuits are very quick to malfunction under the slightest variance to their usual operating conditions.

Yet, there are many industries that rely on electronic products to operate in places where the environment is too hostile or hazardous for even humans to venture – take deep-sea oil exploration, for example.

Others need products that can withstand extreme shocks, such as devices designed for aviation or military use.

And often products are destined for use in extremely sensitive and potentially explosive atmospheres, like those found in mines.

Electronic products are regularly called on to act reliably in many hostile or dangerous conditions. These place the risks posed by the bubbly contents of your sink and gloopy contents of your saucepan to shame.

They include environments with:

  • Extreme temperatures, both hot and cold
  • Severe temperature fluctuations
  • Dust-filled air
  • Explosive conditions
  • Excess moisture or salty water
  • Jolts, vibrations and regular or continuous impact
  • Sudden power surges

In extreme circumstances your EMS partner is your best friend

How can electronic products be produced to withstand these challenging and dangerous situations?
The requirements of hostile or hazardous environments add multiple layers of complexity to the manufacturing process. Yet, your EMS partner can help you design and purpose-build devices to specifically operate in many different conditions. It requires the application of specialist techniques and processes throughout the product’s design and manufacture.

Beneath the waves

The marine industry and oil research facilities need sub-sea rovers and maintenance machinery to operate deep in the briny depths.

Many of these products are operated remotely, so they must be incredibly robust to reliably withstand the sub-sea conditions. The physical challenges faced include the constant threat of erosion by salt and the immense force of the water.

Salt is extremely corrosive. It will eat through metal components and casings if specialist coatings and sacrificial layers are not applied to the product structures and circuitry to protect against this.

Conformal coatings act as a protective varnish for circuit components and casings. These coatings are best applied via robotic, automated processes to increase cost-effectiveness, precision and consistency.

Encapsulation of circuitry provides an extra level of protection for the components, effectively closing them off from external elements.

Conformal coatings

Conformal coatings are not just used for underwater protection: printed circuit boards are often dipped in coatings to protect them from moisture, heat and dust particles.

There are several types of these thin layers of polymeric film that can be used – but each has its pros and cons.

Depending on the environment in which the product is to be used your EMS partner may suggest:

  • Urethane resin
    Good chemical, humidity and mechanical wear resistance
  • Epoxy resin
    Excellent performance in harsh environments with good abrasion, moisture and chemical resistance
  • Silicone resin
    Performs well in extreme temperatures and has good corrosion and chemical resistance
  • Parylene
    Best performing of all coatings but not suited to extended exposure outdoors
Explosive situations

Products which are designed for use in areas contaminated with toxic substances or carbon dust have to be manufactured to withstand contact with these particles.

Your EMS partner must ensure that all ‘critical parts’ are correct to specification. Faulty circuitry can create an over-current – and the resultant overheating increases the risk of explosion.

It is essential that the supplier of every single component part has been vetted and validated. Every single part must be 100% reputable and offer guaranteed batch traceability.

Relying on reputation alone, however, is not enough. Goods inward inspection criteria must use enhanced checks and measurements, rather than trust visual confirmations. It will also be necessary to employ batch segregation for any mixed stock received.

Impeccable material control governance will be used to ensure that each part is fitted into the correct location. This is not as simple as it sounds: the vast majority of small footprint SMT components lack markings but are visually identical, and over 500 distinct parts can be used in a single printed circuit board.

To handle these complexities, we use barcoding and intelligent materials tracking, such as RFID enabling and automated kitting. These techniques remove the very real possibility of human error when handling such sensitive products.

Further checks must be made after fitting for final verification. Once again inspection by a human is far too prone to error for this operation – and highly unlikely to be sustainable over such a high volume of parts. Automated optical inspection is absolutely necessary.

The shock factor

The sheer thrust of acceleration created by rocket-propelled devices requires careful component selection in order to ensure the device is sufficiently robust to survive the shock of take-off. This is especially true for devices with motion potential, such as gyroscopes, valves and actuators.

Your EMS partner can ensure optimal assembly integrity, starting from the bare PCB’s rigidity. Here thickness and copper weight must be balanced against payload constraints. It’s a delicate balancing act, and often to pull it off additional bracing from bonded layers, struts and multiple restraint points will be needed to provide the requisite strength.

Rough and rugged

Electronic products that are designed for harsh conditions are often referred to as rugged. There are actually four categories of rugged electronics:

  1. Commercial grade
  2. Durable
  3. Semi-rugged
  4. Fully-rugged

It’s important to realise that ‘ruggedising’ entails a lot more than simply slapping a sturdy case around the usual configuration of components. As already highlighted, many critical decisions will have already taken place at component choice and fixing stage, well before a case is even considered.

Fully-rugged computers, for example, are designed to withstand elements that would fry most PC circuitry or shock it out of any semblance of working order. US military grade computers must achieve MIL-STD-810G, as rigorous a testing requirement as the most severe drill sergeant ever offered his troops.

To manufacture suitable housings there are a variety of plastics available. These include acrylonitrile butadiene styrene (ABS), polycarbonate, polyphenylsulfone (PPSU), ultra-high molecular weight polyethylene (UHMW) and nylon. These tough materials can be used in combination to increase impact resistance, and elasometric polymers can also be added to deform during impact and reform after.

When the heat is on or the big chill hits

In extreme temperatures solder integrity is absolutely critical. What’s more, this base process must not only be robust but repeatable.

While intelligent automation offers an ideal way to ensure consistency, the intelligence here comes not from the machine itself, but from the knowledge and expertise of the EMS partner’s engineering teams who must establish its operating criteria.

Explosive environments and intrinsic safety

It is usual for electrical equipment to create tiny electric arcs and to generate heat. Under normal circumstances this presents no problems, but where there is a concentration of flammable gases or dust, such as petrochemical refineries and mines, this can become an explosive ignition source.

Intrinsic safety (IS) is a certified technique to protect against this and ensure that electrical equipment can operate safely in hazardous areas. It does this by limiting the electrical and thermal energy in the device.

An example of where this is required is marine transfer operations involving flammable products. During the transfer from marine terminal to tankers it is vital that two-way radio communication is maintained in case of an incident. To enable this the radios used must be certified as intrinsically safe.

There are actually many other ways to make equipment safe for use in explosive-hazardous areas. These include using explosion- or flame-proof enclosures, encapsulation, sealing, oil immersion, venting, powder/sand filling and dust ignition protection. However, intrinsic safety is the only realistic method to use for handheld devices.

On the record

Accountability and documentation are particularly critical when developing products for harsh and hazardous environments. As so many complex conditions and procedures are involved, it’s essential that every step is prepared, researched and accounted for.

Your EMS partner will ensure that the documentation and certification you need are easily accessible at all times. And you’ll certainly be needing this evidence trail to demonstrate continuous control and traceable processes which form the basis for evidence of compliance to industry standards and regulatory requirements.

The true value of your EMS partner when manufacturing for harsh environments

Understanding the complex regulations, industry standards and latest best practices involved in making devices safe for use in different conditions is one way your EMS partner can be your best friend and safest bet.

By suggesting other, or complementary methods, they can ensure that your design is suitable not only for manufacture and regional or industry-specific requirements, but also for its intended end use.

With an increasingly complex and ever-changing supply chain they also act as your eyes and ears in ensuring that components used are exactly as required.

And through robust and rigorous checks they can ensure that the final product is 100% fit for purpose and for the environment it will be used in. Even if this environment is the kitchen sink or a bubbling pan of gravy and the product is your mobile!

A shift in power: How high output batteries are changing the power device manufacturing landscape

by

John Johnston, NPI Director, Chemigraphic

Power management devices are now being used in unexpected places thanks to emerging sectors such as Electric Vehicles (EVs), creating new challenges and opportunities for the supply chain.

In the past, the power supply market was dominated by wire-powered equipment which would take power from the supply grid, either in the form of single-phase domestic mains power or three-phase industrial formats.

This equipment would power circuits handling currents from 20-100A, taking the form of motors, transformers, industrial process equipment and high-output power supplies.

However, with the growth of new sectors and technology such as EVs, a new high power source has emerged on to the scene in the form of high-output battery systems, where Direct Current (DC) needs to be converted to Alternating Current (AC).

Generating and converting power

The AC power generated by the grid and used to drive high AC loads such as motors and transformers requires minimal interface circuitry. However, in electric vehicles, battery sourced power is DC, but still drives a multitude of AC loads. Therefore, there is a requirement for a large amount of DC to AC conversion, and also AC back into DC for power-saving features.

So what does all of this mean?

High-power battery systems, and electric vehicles in particular, consume a large number of current switching devices to manage all the conversion and power governance. This is a complex process which requires careful management and a level of new industry thinking in terms of who and what is using manufactured power supplies.

Changing the power play: a new approach

These shifts in the market and the proliferation of current conversion needs have sparked a demand for high-current switching devices on a large and growing scale.

This increase in demand has in turn made it very attractive for power management device manufacturers to divert their capacity and raw materials away from “traditional” power devices and towards newer, eV-based variants.

As part of this supply chain, we are seeing established current-switching devices such as Metal-oxide semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs) becoming subject to higher-levels of stock limitation and obsolescence.  As more conversions are required, more of these devices are being purchased and stockpiled, having a profound impact on the supply chain.

So what’s next?

There is no magic solution.

Unless an OEM has sufficient scale and spend to leverage device manufacturing commitment and capacity, then more fluidity in the power device market is an unavoidable eventuality.

Taking a proactive view of design, monitoring the supply chain and the market landscape for changes and developments is the best approach.

As a result, options can be kept open to authorise alternative parts or look to incorporate alternative circuity. Engaging with a high-capability EMS partner can help OEMs to investigate and validate these options, utilising the partner’s market expertise and knowledge of the manufacturing process.

Looking to the future

This trend in power devices being shifted to new markets will not end here.  Renewables will be increasingly used in power generation, although it is difficult to predict which other formats will join the prime source of on and off-shore wind turbines.

The core power management levels in these systems tend to sit well outside the scope of semiconductor devices, but their remote nature then drives the need for ever more complex auxiliary management systems.

One thing is for certain, however. As technologies evolve and new markets emerge, the whole electronics supply chain will continue to be challenged and tested in terms of the products we build, the parts we use to do so and the approaches we use to manage the process.

Bring it on, we are ready!

Systems Integration: More than just a box of tricks

by

Box-building is typically used to paraphrase the challenging stage of bringing together the many components within a single, ready-to-go product. This idea of simply connecting up various elements to create a box of tricks remains one of the EMS industry’s most understated descriptions. It remains a highly complex manufacturing process where the expertise and facilities of your EMS partner makes a big difference to your final product. Most importantly, this expertise begins before the box is even designed…

 The term ‘systems integration’ provides a more meaningful description of how Chemigraphic brings together custom PCB assembly with sub-assemblies and modules, enclosure design, fabrication, cabling and wiring. We transform these elements into complex, multi-tier systems – often sophisticated machines – and make ready through testing, software, programming and calibration.

Below are some key considerations regarding the systems integrations process.

PCB assembly should be a core offering

By offering PCB assembly (PCBA) using both Surface Mount Technologies (SMT) alongside conventional Pin-Through-Hole (PTH), it’s possible to check and guarantee the quality of components within the system. We are the only UK EMS to use automated JUKI SMT kitting machines and the automation allows us to build to specification, removing the opportunities for human error and reducing labour costs. We have unrivalled component management systems which allow us to place components in the most detailed configurations, meaning we can assist customers with any project, no matter how complex.

Think about the box build early on

Enclosures and casings are essential components of System Integrations – plastic and metal, or combinations. There are many off-the-shelf choices available, often with the advantage of lower unit prices and small minimum orders, but rarely this is without sacrifice – it won’t be unique, the components may not fit correctly, and there’s always the possibility a supplier might modify or withdraw the product. The need to fit PCBs securely alongside other electronics, modules, wiring and fans often drives our customers towards bespoke enclosures.

Since plastics and polymers are most commonly used it’s critical that an EMS supplier understands the differences between materials and manufacturing techniques. For instance, ABS is only suited to indoor environments as it will be compromised by prolonged exposure to sunlight, whereas ASA+PC resists high temperatures and harsh environments. New techniques such as MS-MMM injection moulding can incorporate soft-touch textures and colour, which avoids the use of different suppliers. It’s the job of an EMS provider to pass on this knowledge as customer benefits in the form of shorter, more reliable supply chains and economies of scale.

Chemigraphic also incorporates any metalwork using only carefully vetted suppliers of precision-fabricated materials. Coatings may be necessary to protect both the casing and components against the weather, corrosion, conductive or toxic dust particles, water and general contamination. In these instances we use automated equipment to apply protective coatings to selected board locations, increasing efficiency and reducing both the opportunity for human error and labour costs.

Don’t get in a tangle with wiring

The complexity of cable and wiring can vary enormously between System Integration projects, from a few wires stripped, twisted and tinned to complex harnesses with more than a 1000 ends and a multitude of terminations. Most projects require customised wiring – lengths, colours, special pin-outs, identification, connectors, etc. Our automated cable ‘cut and strip’ machines can accommodate low-volume complex harnesses through to medium-volume cable assemblies. Via our Shenzhen office, we can source and co-ordinate the entire supply chain with certifiable traceability.

Off-the-shelf still requires customisation

Many customers choose to make use of widely available Commercial Off-The Shelf (COTS) modules – boards and mezzanines, controllers, HMIs and displays, power supplies, etc. Development costs and timelines can be reduced using pre-tested sub-assemblies, but should be balanced against higher unit costs and possible compromises on functionality. We’ve found the most successful system integration projects take a hybrid approach, using both COTS and custom-builds to best fit the customer’s immediate and future requirements. It is rarely true that by purchasing a COTS product, no bespoke work will need to be performed. Chemigraphic has a wealth of experience integrating and combining COTS modules into larger systems. We use our Asian sourcing office to gain attractively-priced components.

Take extra care with moving parts

Electro-mechanical assemblies containing switches, electronic controls, gears, rollers, etc, contain moving parts and are inherently more challenging. Conflict with other parts especially from different manufacturers are routinely discovered. Chemigraphic has knowledgeable, specialised purchasers who are in touch with the global components markets. We use CAD 3D modelling equipment to improve the design process and have a well-equipped inspection area containing microscopes and electrical testing devices.

Honey, we shrunk the circuits: The amazingly small electronic products

by

Electronics are shrinking.

Don’t let the rate at which smartphones have grown since the early years of this millennium fool you.

(Source)

The future of electronic products is to get smaller and smaller.

And these smaller devices will offer ever greater capabilities while using less power.

Smartphones’ growth in size belies this trend, but it’s a reflection of the fact that they have taken on the role of so many other devices.

It’s the need for a bigger screen that has led to their burgeoning size.

But look how slim they have become as their screen size grows.

(Source)

Consumers want smaller gadgets that can do more – and do it quickly.

So, the smartphone has become a pager, powerful camera, video recording and editing device, media player, sat nav, eBook reader, personal organiser, word processing tool, games machine, credit card, scanner and a lot more besides.

Less is Moore’s Law

The journey towards miniaturisation is being aided by advances in screen and battery technologies, but sitting right there in the driver’s seat are developments in components and circuits.

And it’s not just consumer goods that are getting smaller and smaller – this trend extends to industrial technology too.

Wherever you look less is more, and this is known as Moore’s Law.

Moore’s Law has held true for nearly 40 years now.

In truth, it’s more an observation than a law. It suggests that electronic devices will double in speed and capability about every two years.

What Intel co-founder Gordon Moore actually predicted was that ‘the number of transistors incorporated in a chip will approximately double every 24 months.”

And transistors are the tiny electrical switches that lie at the heart of any electronic gadgets you can think of. As they shrink they also get faster and consume less electricity.

Moore’s Law in effect

(Source)

It’s not just transistors that are shrinking, however.

The humble capacitor was once, in the 1970s, made from bulky axial leaded parts. These were replaced by the slimline 1206 ‘surface mount chip package’ which, at the time, appeared to be an impossibly microscopic 3.2 x 1.6 mm. But now we have 01005 packages, offering a further volume reduction of 98.5% and measuring just 0.4 x 0.2 mm!

Similarly, it wasn’t all that long ago that the tiny 60 x 60 mm IC (silicon chip) device, with 160 connection pins around the outer perimeter, was considered cutting-edge. Yet, its equivalent is now the 30 x 30 mm ‘micro-ball grid array’. This sits on a matrix of 900 solder sphere connections – and requires the use of an X-ray to fully inspect.

In recent years many have wondered if Moore’s Law is coming to an end, as components meet the limits of possible shrinkage.

Companies like Intel can mass-produce transistors 14 nanometres across – that’s just 14 times wider than a DNA molecule. They’re made of silicon whose atomic size is about 0.2 nanometers.

With transistors hovering at about 70 silicon atoms wide, the possibility of making them even smaller is starting to shrink.

We’re getting very close to the limit of miniaturisation.

We’ll return to this in a moment – first, let’s take a look at why small is considered so beautiful.

The miniature revolution in electronics

The miniature revolution in electronics is being driven by:

  • Aesthetic demandsWe have come to expect our tech devices to be design-statements and things of exquisite beauty.
  • Portability

    Our wireless devices should be easy to take with us. Light weight devices are enabled by the miniaturisation of components and PCBs, reduction in battery sizes and developments in plastics and metalwork.

(Source)

  • Cost savingsWhile cutting-edge miniaturisation can come at a premium, the use of less materials usually provides a reduction in cost in the long-term. Especially when the electronics industry absorbs and adopts innovations and the production costs for increasingly smaller parts shrinks correspondingly.
  • Eco-friendly power consumption reductionsSmaller parts use less power. This reduces running costs, extends battery life and offers greener products.
  • Less heat dissipationAs smaller parts consume less power, they lead to electronic products which generates less heat. When heat dissipation requirements are sufficiently reduced this can avoid the need for bulky heatsinks and mechanical fans. This, in turn, further reduces weight, cost, power consumption and intrusive noise.
What impact have smaller components had on electronic manufacturing?

(Source)

From an EMS and product manufacturing perspective, perhaps the most significant impact of this reduction in scale is the increased need for automation and use of robots.

The sophisticated soldering technologies now required to fit components and parts is no longer possible by hand. The precision required can only be carried out using high-tech equipment operated by skilled engineers.

It’s not just production that has become increasingly automated.

With components getting smaller and smaller they become, to the naked eye, identical. Many components no longer have any space to carry distinguishing codes or other markings to aid identification.

It has never been more important that your EMS partner can offer you a fully traceable and trackable supply chain and uses barcodes and sophisticated machines to inspect, select and verify (as well as place) every component used. Robust materials control is essential at every step of the supply and manufacturing process.

Are our shrinking days no Moore?

Many industry commentators have suggested in recent years that the gains we have enjoyed under the rule of Moore’s Law may be coming to an end.

Of course, we all believed things couldn’t get any smaller many times in the past.

But they did.

What’s different today is that we really are reaching the point where physical components are constrained by the demands of matter.

So, what’s next?

Some interesting developments that suggest we haven’t exhausted the potential of further miniaturisation include:

A team led by Robert Wolkow had long-known how to reduce circuitry to an atomic scale, but they have only recently found a way to perfect a technique that allows these circuits to be mass produced.

They suggest that this breakthrough could help manufacture smartphones that operate for months between charges and computers that run a hundred times faster but use a thousand times less power.

It looks like it may still become a smaller world after all.