Rethinking the Supply Line

The PCB fabrication industry is older than most of us still working. It is overdue for modernization. We have not seen transformational manufacturing changes in the PCB bare board industry during the past 15 years.

What we have seen is the installed capacity moved to China. It has been reported that 60% of global board fabrication now comes from mainland China or Taiwan. This move created a forced shift in how boards are purchased, and consequently created new demands in communication and logistics. Specifically, language, time zone, and cultural considerations. Bigger companies with China-based feet on the ground could adapt easily; the rest of us had to learn new skills.

I am suggesting that the rest of us modernize and rethink our supply line strategy.

Some may remember the evolution of the electronics component industry. First, component manufacturers sold directly to OEMs. Gradually, customers and component manufacturers found that a better path was through a local distributor. Arrow, Avnet, Future, DigiKey, and many others were born out of this efficiency. Today, it is an exception to buy directly from a component manufacturer.

PCB fabrication is difficult for distributors because every board is custom. Repeat: every board is custom. Custom equals high potential for error, which equals close technical review required.

So, buyers must go to China directly and slog through the variety of China sources. With this come the multiple challenges of accountability, communication, logistics and culture. The most dangerous of the challenges is having picked a supplier that occasionally (or often) sends subpar boards and provides no recourse or no response to your complaint. Do you really want to commit such a critical part of your BoM to the lowest China bidder?

The modernization of the PCB industry is not in processing, but in supply chain. A new category of value-added distributor is evolving in the same way the component distributor evolved … to make things easier. We call it “Managed Manufacturing Services.”

Think of it as a value-added distributor of printed circuit boards. This concept can greatly improve the supply chain for both customer and China manufacturer, but only if they really add value.

What are the important values, and how does this approach add value?

Technical support. The value-added distributor must be your expert design reviewer, capable of counseling you and quickly fixing the errors.

Only technically trained PCB teams really understand the manufacturability challenges of bare boards. With the technology of new IC packages pushing toward smaller geometries, new thinking is required about designing for manufacturability. So, your value added distributor has to be technically trained to provide this service.

Communication. The value-added distributor must be capable of clearly and cleanly communicating with a factory in a different country.

We have been working with offshore factories for a long time. We learned through hard knocks that developing a strong relationship with your counterpart in Asia is critical. I call it “Pitcher-Catcher.” Whether a fastball or a curveball, the two communicate in one cohesive motion. This takes time to develop and not every factory gets it.

Time zones can work to your advantage. We pitch everything to China by 5 pm Pacific and have answers at 6 am the next day. Your distributor must know the factory requirements well enough that only a few questions (EQs) come back, lessening the need for middle of the night conference calls.

Accountability. Your value-added distributor must have carefully vetted and audited the factories they use. They must be US corporations with financial accountability to their customers.

Slogging through a variety of factory options is not a good idea. Jumping from one to the next based on price and email pressure is also not a good idea. It wastes time and invites disastrous quality issues. Customers with little or no knowledge of what makes a solid factory are at particular risk. Yet most customers fall into this category.

If you have someone on staff with experience in this area, you can send them to China to visit multiple factories, but unless this person has in-depth knowledge of what makes the difference between okay and fantastic at the granular level, it is waste of $10,000. It takes deeply experienced people to see the difference. It takes board manufacturing experience.

From the China manufacturer’s side, it is just like the component manufacturers of old. It is much more efficient to deal with a small handful of companies who service the US market than it is to staff and service everyone. The culturally smart ones are beginning to see this and actually do view us as distributors for them. It is a proven supply-chain solution.

Following the model of the component distributors, we can modernize this PCB industry. We can improve efficiency, quickly adopt new technologies, and capture lower costs all by modernizing the supply chain. Welcome the value-added PCB distributor, or as we call it Managed Manufacturing Services.

Thomas Smiley is president, Precision PCBs; tsmiley@precisionpcbs.com.

Accursed Diode Marking

Am I a broken record? Pretty much — especially when it comes to confusing diode marking.

For example, everyone knows what the diode symbol looks like, and pretty much everyone knows which side is the anode and which is the cathode. Right? It’s just like in the following picture:

10 designersnb figure 2

Is that big enough?

Normally, the clearest way to indicate polarity on an LED is to put something like this diode symbol in silk screen next to, or between, the copper pads. In theory, that should remove ambiguity.

Ambiguity in marking is the enemy of polarized parts. Unfortunately, as I cover in this, and many other blog articles, LED manufacturers seem to conspire against us all when marking is concerned.

We recently ran across a case of built-in ambiguity. The PCB had, what looked like, a very clear marking. The image on the right is from the assembly drawing, which is just a blow-up of the board silk screen and documentation layer.

With that marking, I’d quickly come to the conclusion that the anode is on the right and the cathode is on the left. I’d even confidently state that it’s a sure thing and extremely unlikely to cause any problems. But …

Here’s where I’d be very wrong, and why it’s so important to always check the datasheet when dealing with diodes. Take a look at the following clip from the component’s datasheet. Scroll down to the bottom of the image for the punch line.
10 designersnb figure 3

Wow. I can’t even …,

The board designer was just following the datasheet. That’s a perfectly proper thing to do, except when the manufacturer flips a coin, as it appears to have happened here. In this case, dispense with the symbol altogether and use “A” for anode and/or “K” for cathode in the silk screen. (Use “K” because “C” looks too much like a reference designator for a capacitor.)

Duane Benson
In the land of the insane, only the sane are crazy

http://blog.screamingcircuits.com/

Where to Put Panel Tabs

Many small quantity PCBs are ordered individually cut. They come to us as a set of unconnected boards. For small quantities of reasonable size boards, it makes the most sense to order them this way. However, for really small boards, and larger quantities (50 or more), purchasing boards in a panel (also called an array) is more appropriate. It reduces errors and assembly time.

There are a few additional factors to consider with panelized boards.

  • First, don’t try to create a panel in your CAD software. Just lay it out as a single board and have the fabricator put it in a panel. You’ll get the most efficient use of PCB space that way, and the fabricator will create the files in the format that the assembly shop (Screaming Circuits) needs.
  • Avoid family panels. A family panel is when several different boards are put onto the same panel. The boards in family panels often repeat reference designators, which causes problems at assembly. See this blog article on how to properly assign reference designators on a family panel.
  • If you have overhanging parts, like the increasingly common micro USB connector, make sure that the panel tabs aren’t placed near the overhanging them.

This blog article gives some background on the connectors.

Some components, such as the connector in the link above, have protrusions that will keep them from laying flat on a panel tab. In all cases, even without the protrusions, the operation of separating the panels with a component on the tab can weaken the component solder joints, or even pop it off the board completely.

How not to do it:

Figure 1

Figure 1

Instead, make sure that the tabs don’t end up under your overhanging component. Have the tab moved like this:

Figure 2

Figure 2

You can put this instruction in the document layer of your CAD file, or in a separate document covering fab instructions. In the CAD image below, the overhanging component has a keepout area. The document layer has instructions to keep panel tabs out of the area.

Figure 3

Figure 3

If in doubt, don’t hesitate to contact us or Sunstone Circuits directly to ensure that your instructions are clearly communicated.

Duane Benson
Wood paneling as a wall covering is really out of style

http://blog.screamingcircuits.com/

Proper PCB Storage — The Top 3 Hazards

It’s late. Do you know where your printed circuit boards are? Let me rephrase that: Can unused PCBs be stored for future use?

Yes, they can – if stored properly. Keep them wrapped up, or sealed in a bag. Anti-static isn’t necessary in this case, but it won’t hurt. Keep them in a cool, dark place. Keep them clean. Do your best to avoid dropping them on the floor and stepping on them.

The board in this photo was left out on a desk for a while, and then shoved into a desk drawer. The environment took its toll on the immersion sliver finish, making it very much unusable.

PCBstorage

What can go wrong:

1. Fingerprints. The oils on your finger can etch fingerprints into ENIG or immersion silver board surfaces. If you plan on committing a crime go ahead and do this so we can catch you. If you aren’t going to start a life of crime be careful to not get your fingerprints on the board surface. Handle on the edges, or at least, don’t touch any exposed metal.

2. Moisture. Moisture is good for your skin but not for your PCBs. Over time, PCBs can absorb moisture, especially in a humid location, or the ocean. If thrown into a reflow oven they then might laminate. Store boards in a dry environment. If stored for a long time, you may want to pre-bake them prior to use.

3. Atmosphere. Sometimes dirty air can contribute to tarnish or corrosion on the exposed land pads. Dust can settle onto the boards as well. Tarnish and dust can usually be cleaned off, but corrosion can’t. Wrap up your boards for long-term storage.

Treat your boards well and you can likely use them at a later date. Don’t treat them well and you may need to replace them, wasting a bunch of money. Often, the damage isn’t as clear as in the above photo, but could still lead to poor solderability.

Duane Benson
Don’t surf on your silver

http://blog.screamingcircuits.com/

End of Summer — End of an Era?

Which is the way forward? New or renew?

Nepcon in Shenzhen Aug. 26-28 was “OK” in terms of attendance. Lots of prospects/”tire kickers” but very few buyers.

Japan’s high-tech PWB volume in June increased  8.6% over that of June 2013, but revenue declined 4.1% for domestic build-up types of multilayers — a typical sign of declining business, a maturing industry, cheaper foreign sources, and overcapacity. According to DKN Research, prices for these types of circuits used in cellular phones dropped 12% in Japan during the past year.

Japan manufacturers are also engaged in a price war with Taiwanese and Chinese competitors with double-sided and multilayer flexible circuits. Selling prices on these dropped more than 33% in the past year. Overall, the forecast for the Japanese circuit industry for 2014 is not better than 2013’s, which was the worst since 2008.

The world’s top 100 printed circuit makers account for approximately 80% of global demand.

Nothing is forever. The interconnect industry (PCB and PCBA) has had a good run and matured. It has progressed technically, shifted geographically, consolidated, thrived and suffered due to geopolitical shifts as well as technical advances. Some well-known domestic companies are undergoing inversions. Others are shrinking or struggling to regain a profitable (albeit smaller) status after squeezing suppliers, inventories and eliminating much of the R&D funding for future improvements. Renewing appears to be more difficult as competition for “more of the same” continues to increase and value differentiation declines. In fact, some of the cost reduction activities have actually removed value from many of the offerings making them less attractive in the long run.

Change is inevitable! We can contribute to it or be the “victims” of it. We can invest in the future or have no future. We believe that today’s survivors that are experiencing declining options for their current offerings must seek out new directions, new alliances, new wares, new  cooperative development activities and support for the future.

Opportunities do exist! 3D packaging has stalled due to both economic and technology issues. Mitsubishi Heavy Industry has started a new room temperature wafer bonding service for MEMs and biosensors for firms designing 3D packages and are unable to make them themselves. 2.5D appears to not be faring much better. New improvements in packaging appear to be filling some of the current needs and gaps. We can extend product life cycles with product/process improvements while developing new disruptive or not-in-kind technologies.

New flexible substrates with 14 micron thin cores and 9 micron Cu surfaces provide the reality of 25 micron line and space volume production and, along with new technologies, the opportunity of PCB and IC substrate makers, and their supply chains to work more closely with the packaging industry.

Future success will require a total reassessment of your company’s core values, mission statement and goals. It takes a new strategy and action plan. It will require you to question your managements’ styles. Procedures will have to be reviewed, too. Why were these established? Are they still needed? Should they be modified to meet today’s Lean manufacturing needs and technology requirements? Do they support speed to market? Should you change or create new areas of focus? Do all your managers feel the urgency?

What are you doing to ensure your future?

New cooperative activity. The newly established liaison between the IPC and the International Electrotechnical Commission’s (IEC’s) Standardization Management Board (SMB) should be a boon for the rapidly growing printed electronics industry. All concerned parties have something to contribute and something to gain from this collaboration to create international standards. One must, however, keep an open mind for new potentially disruptive technologies that could potentially bridge some applications of the areas encompassed by printed electronics, printed circuits, and other packages.

It’s time to get serious. The Taiwan Printed Circuit Association (TPCA) has asked for government support to help Taiwan’s PCB industry develop next-generation products to counter slowing growth rates. The nation’s industry (including output from its factories in Mainland China) will generate sales of $18.3+ billion this year. The TPCA is likely to receive a good audience from the government as the nation’s vice president has been a keynote speaker at the annual TPCA show’s opening ceremony the past few years.

Shortly after announcing a new $30 million share repurchase program this month Plexus held an opening ceremony for its $40 million 265,000 sq. ft. manufacturing facility in Guadalajara, Mexico. The company has stated that it is now actively recruiting to fill employment opportunities. Full employment at this facility is expected to exceed 700 workers.

The increasing costs in China and elsewhere, the stability and availability of a skilled and semi-skilled work force, locally established supply chains, and the proximity of five universities are all sure to have contributed to the decision.

SEMI announced another positive book-to-bill IC equipment order ratio for the month of July. Where will the equipment go? What types of chips with what nodes will it build? What industries will consume the added production? When will the PCB/packaging industries partake in the results?

Who is building the packaging substrates and where are they built? Taiwan Semiconductor Manufacturing Co. (TSMC), the world’s largest contract chipmaker, yesterday said its revenue hit a record high $2.16 billion last month up 7.6% from June and 24.6% higher than a year earlier. The company also forecast a sequential revenue increase next quarter because of its strength in 28nm and 20nm process technologies as well as strong demand for flat panel IC drivers and tablet power management chips.

United Microelectronics Corp. (UMC), Taiwan’s second-largest contract chipmaker, posted its lowest revenue in three months last month, down 7% to $380 million due to lower contribution from its solar business.

Conversations with several major circuit interconnect and packaging supply chain members in Singapore, Hong Kong, China and Japan indicate that business is “spotty” at best. KCE in Thailand is having record sales participating in circuits for the automotive after market, now the 2nd biggest in Asia. Unimicron Technology’s second quarter net profits were up 377% from the previous quarter to $9 million. Gold Circuit Electronics and M-Flex are still working to restore profitability. Viasystems lost money the second quarter of the year. The second half of 2014 looks promising for Taiwan-based circuit makers. Global Innovation has restored its Lone Star name with a statement that it will only provide domestically produced circuit boards.

SEMI has forecast double-digit growth for equipment makers for the next two years. What will the applications be? Will Intel’s new 14nm node be part of the surge, or will the cost/benefit ratio not be good enough? How much of an effect will “wearable electronics” have?Which substrate/board builders will benefit? When? Where?

Samsung’s smartphone market position in China has been supplanted by Xiaomi  and in India by “home-grown” Micromax in the 2nd quarter of 2014. The latter is offering a 6-inch screen with magnetic flip cover, 1.3 GHz dual-core Media Tek processor, and an Android 4.2.2 Jelly Bean operating system with a 5-megapixel camera and a 6-month movie subscription for $140 (8,500 rupees)!

How is your crystal ball? Are you monitoring and re-evaluating your attainable markets and shares? Are you redefining your businesses? have you found creative ways of extending product life cycles? Are you noting major shifts in supply chains and aligning your companies with the king (or prince) makers of the next few years? Are you redefining your markets and stepping “outside” the traditional boxes? If not, I suggest (re)reading Blue Ocean Strategy by W. Chan Kim and Renée Mauborgne (2005, Harvard Business School Publishing, 2005).

As a supporting organization of the China Sourcing Fair Fall 2014, Electronics & Components, to be held on October 11-14, 2014 at AsiaWorld-Expo, at the Hong Kong Airport, the HKPCA is offering its members VIP Buyers’* privileges to this Fair.  These include:
– Free admission to the fair;
– Free transportation arrangements to the fairs;
– Coupons for F&B & shopping discounts at the Hong Kong International Airport area and AsiaWorld-Expo;
Exclusive use of onsite office suites to its invited VIP buyers (Wifi connection, office equipment, etc);
– A free Octopus Cash Card with HK$150 stored-value for transportation or purchases.

 

Warped PCBs

You just got a nice big PCB back from the fab shop. You set one on your desk to admire only to discover that it’s warped. What do you do?

There are two primary types of causes of board warping: process related at the fab or assembly shop, and layout-related issues. If it’s warped before assembly, it’s between fab and layout. If it’s flat before assembly and warped, after, it’s most likely between layout and assembly — although sometimes a fab problem won’t show up until a pass through the reflow oven at your assembly partner.

Determining the root cause is generally a bit of an iterative process. It’s tempting to start right off with your fab or assembly partner, but you need some information before giving them a call. You’ll need such things as the amount of warpage per inch, board size and thickness. With that, you need to take a good look at your design and consider copper pours, component size and component placement.

With that information in hand you can make your phone call. If the board is warped before assembly, call your fab shop. If it’s flat pre-assembly and warped post-assembly, call your assembly house.

The shop you call will want to talk over your design to help you pinpoint the cause. If you can rule out a design issue,then you need to talk with your partner to determine whether it’s a fab or assembly issue and next steps to take care of you.

 Here are a few design issues that could contribute to warping:

  • Uneven copper pour. Copper and FR-4 are a good match relative to thermal expansion, but they aren’t exact. A large pour on one side or corner of your board can lead to warping due to dissimilar expansion characteristics. This could cause warpage either at the fab shop or the assembly house.
  • Components with large thermal mass grouped together on the board. This would be more likely to cause problems during assembly than during fab. The thermal mass will act as a heat sink for that area on the board, which can lead to uneven expansion and uneven soldering.
  • A board that’s too thin for the size or number of components could lead to warping at any stage.
  • Odd shapes or large cutouts could also lead to warping at any point.

There may be other, more obscure causes, but those are the main design related causes. If it’s none of those talk with your partner.

Occasionally, design requirements lead to a board that is essentially non-manufacturable. Hopefully you never have this situation, but if you do, make sure that thickness, component location, pours, or cut outs really, really, really, need to be the way they are.

If you absolutely, positively can’t change anything, go back and try again. Then you can to look for heroic means to get the board fabbed and built.

Slight warpage might go away when the board is mounted. Just be careful with that. Some components may not stay securely soldered when you flatten it.

The board may need a special fixture during assembly to prevent warping. This will likely cost extra, but if you can’t change your design, and still need it built, it may be your best option.

Finally, if nothing works, you may need to look harder at the design, or look for a new fab or assembly house. We all like to think we can do just about anything, but every shop has its limits, and on rare occasion those limits can be difficult to spot.

Duane Benson
What if Godot was late because he was waiting for John Galt?

http://blog.screamingcircuits.com

Component Packages — Let’s Get Small

I’ve been on a bit of a package binge lately. First talking about metric vs. US passive sizes, and then a very tiny ARM Cortex M0 from Freescale.

The Freescale BGA part checks in at 1.6 x 2mm. That’s cool and I’m almost always in favor of making things as small as possible, but, as I wrote in my prior blog on the subject, it’s not always possible. The 0.4mm pitch BGA is problematic unless you can spend a lot of money on the raw PCBs, or will have super high volume.

All is not lost, though. You still can use a tiny ARM Cortex M0 part. Just not quite as tiny. That same part also comes in a 3 x 3mm QFN package. You lose four pins (16 vs. 20) going from the BGA to the QFN, but if you can handle that, it’s a very viable option that doesn’t require any exotic circuit board technologies.

A few years ago QFNs were scary, but not so much any more. I’ve designed a few of them in using Eagle CAD. Just be sure to pay attention to the footprint. A 6 mil trace is more than small enough for a 0.5mm pitch QFN.

Duane Benson
Strive at all times to bend, fold, spindle and mutilate

http://blog.screamingcircuits.com/

Collins Closing

Count me among those sorry to hear the news that Rockwell is closing its printed circuit board fabrication plant.

I’ve been through that plant and this is sad to see. I wrote a profile of the plant for PC FAB in 2000. At the time, then GM Mike Driscoll was overseeing a major implementation of Lean manufacturing, making the site one of the early adopters of the practice.

I’m of the opinion (minority, probably) that OEMs retaining in-house knowledge and expertise of manufacturing processes is a good thing, even if they can’t necessarily generate a direct profit from it.

That, plus I knew several people who worked in that shop over the years and every one of them is a class act.

There are still a few major OEMs with in-house fab capacity. Let’s hope they see fit to keep it.

 

Updating the Design Standard

IPC-2221A, as most designers know, was released in 2003. Since that time, lead-free has gone from a niche technology to a mainstream one, and its added a generous dose of complexity to the design decision tree.

In November, IPC-2221B was, at long last, released, and it’s a good opportunity to reflect on the process of how standards are developed, and why it took nearly a decade to get the latest rev out.

In that time, for example, the task group responsible for J-STD-001, the industry soldering standard, came out with a “D” and an “E” revision, and work is underway on the “F” revision.  Certainly the changes lead-free brought about affected electronics assembly at least as much as design: it’s hard to pin the problem solely on technical reasons.

My experience working on the J-STD-001 suggests the difference in publishing frequency comes down to how the respective task groups call a halt to the changing technology. Going back to when Jerry Rosser was chair of the J-STD-001, for example, that group has a 15-year-plus history of calling a hard stop to new technical additions after a set period of time. Jerry knew the standards would always be disrupted by new technology, and therefore he initiated a plan — still followed — whereby after a period of months, the spec would be frozen, and the only changes from that point to the revision in progress would be to ameliorate the grammar and, on the rare occasion, fix legitimate technical disputes. If, for example, new chip-scale package requirements weren’t ready by the hard stop, they were tabled for the next rev. The ensuing document was never perfect, but it was far more timely than would have been otherwise possible.  To wit, the task group published four revisions, plus one amendment, in one decade alone.

Based on interviews with the coordinator of the IPC-2221, a different tack was taken, which slowed the process considerably.  It took the task group several years before calling a hard stop. Another difference is the decision to include a fair amount of tutorial in the design standard, whereas the soldering task group stripped all that info out years ago, opting instead to segment it into a separate handbook.

Now, to be sure, there is a design guide, but it was published in 1992 and has never been updated. I understand the philosophical reasons for doing things the way the design task group has done them, but in the interest of faster time-to-market, I think it’s time to reconsider whether there’s a better way. Thoroughness has value. But so does expediency.

Associations in Agreement

Taiwan’s Vice President Wu (tallest man, center of photo) welcomed visitors and took part in the ribbon-cutting ceremony for the TPCA Show held in conjunction with the IMPACT 2012 event in Taipei. Second from the right is IPC CEO and president John Mitchell.

The TPCA and the JPCA signed a Memorandum of Understanding at the Taipei Nangang Exhibition Center on Oct. 25 to highlight industrial cooperation in a practical and efficient way. The TPCA organized an Alliance Seminar held in conjunction with the endorsement. This followed the Advance Technology Forum alliance event of this past July. The activity is supported by Taiwan’s Economic Department. Approval of funding was announced after the signing.

IMPACT 2012 was jointly organized by IEEE CPMT-Taipei, iMAPS-Taiwan, ITRI and the TPCA, and co-organized by IDB-Ministry of Economic Affairs, I-Shou University, NanKang IC Design Incubation Center. SMTA, and TTMA. IMPACT (International Microsystems, Packagiing, Assembly and Circuits Technology Conference) attracted 190 papers from 14 countries.

The TPCA held a special breakfast presentation in which an update on the industry in Japan (PCB domestic production down 45+% from its peak in 2007 as offshore manufacturing increased) by Dr. Hayao Nakahara of NTI and the industry status in Thailand presented by Bancha Ongkosit, chairman and managing director of KCE Electronics. The latter stated that Thailand lacks supply chain infrastructure and that he no longer buys from the US. He pointed out the growth of automotive electronics, stating that virtually every major car company as set up there, and that Thailand exports about 3.5 million vehicles per year. He also stated that the growth of organic substrate replacement for ceramic based electronic circuits for vehicles will continue to increase rapidly.

America’s Interdyne Systems, a new fabrication equipment entry debuted its revolutionary new concept for the mechanical drilling of 75 micron holes. Taiwan Kong King (TKK) celebrated its 35th Anniversary at the show.

It’s a Collaborative World After All
Rumors persist that an announcement of a new collaborative activity between the IPC and iNEMI is imminent.

Lenovo, the world’s second largest PC producer, will start production of its Think brand notebooks in the US next year at its fulfillment center in North Carolina. Lenovo acquired IBM’s PC division (original producer of the Think PC) in 2005. Last month Lenovo announced the acquisition of Brazil’s PC maker Comercio de Component Electronicos.

Taiwan’s intelligence chief warned that one in every three Taiwanese companies based on the mainland are facing closure due to rapidly falling profits, according to Agence France-Presse in Taipei. Another 30% are also reported to be struggling on the mainland. Last year the island’s authorities approved 575 mainland investments totaling $13.1 billion.