Author Archives: Mike

About Mike

Mike Buetow is president of the Printed Circuit Engineering Association (pcea.net). He previously was editor-in-chief of Circuits Assembly magazine, the leading publication for electronics manufacturing, and PCD&F, the leading publication for printed circuit design and fabrication. He spent 21 years as vice president and editorial director of UP Media Group, for which he oversaw all editorial and production aspects. He has more than 30 years' experience in the electronics industry, including six years at IPC, an electronics trade association, at which he was a technical projects manager and communications director. He has also held editorial positions at SMT Magazine, community newspapers and in book publishing. He is a graduate of the University of Illinois. Follow Mike on Twitter: @mikebuetow

The ‘Hole’ Truth about Drilling PCBs

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Okay, here we go, blog number 3; but first allow me to do a quick review of what we’ve covered so far:

1.) Not everyone who says they can make RF/MW PCBs really can.
2.) High performance substrates act NOTHING like FR-4 in the fabrication process, and a qualified supplier must be a “Material Guru.”
3.) Just as RF/MW engineering is a specialty, so is RF/MW PCB fabrication.
4.) Don’t be hasty in starting relationships with RF/MW PCB suppliers. Do your homework and ask important questions.

Now, moving along. Let’s talk about drilling holes. Automated drilling machines are incredible, when you think about it. The X-Y axis accuracy of hole placement, the throughput, and the speed of the spindles are all truly amazing! When drilling FR-4 material, the bits cut through material like a hot knife through butter. When you throw some Rogers PTFE, or Taconic in the mix, however, a dramatic shift occurs. The drill operators start throwing back Red Bulls, and all that mindless trust in the drill’s amazing technology vanishes.

Again, remember the Material Guru analogy: for every substrate brand, composition, thickness and copper weight, there is a specific recipe—in this case a drill recipe. (Thankfully, these recipes are supplied by the substrate manufacturers.) The speed of the spindles must be adjusted to keep them from tearing up the softer materials and leaving behind chewed up hole walls. The drill bits must be changed frequently to ensure optimal sharpness. The feed speed must be altered as well, to ensure a clean entry and exit of the drill bits. If you don’t have cleanly drilled holes with smooth hole walls, you will be in deep water once the boards hit plating (no pun intended).

In addition to these adjustments, talented design engineers continually delight us with their ever-so-complex designs that require multiple drill operations (due to buried and blind vias). Sometimes, back drilling or controlled depth drilling is required. All these factors serve to compound the, already complex, challenges. (Yes, there is laser drilling, but that comes with another set of unique challenges — and requires a separate post!)

Needless to say, drilling is a critical step in the manufacturing of RF/MW boards. If you mess it up in drilling, expensive laminates end up on the scrap pile, along with any hope a supplier may have of making a profit. So, here is what I hope you will take away from this brief post: Drilling RF/MW PCBs is dramatically different than drilling standard FR-4 boards. It requires knowledge, skill and experience. It naturally costs more (due to drill bit usage and added labor) and is far more risky, from a profit standpoint, for the supplier. It can be risky for you too, but only if you have inadvertently partnered with an unqualified supplier.

For all these reasons, when you get an opportunity to visit an existing or prospective PCB supplier, keep these things in mind as you ask questions about their drill operations. If you see wide-eyed drill operators, a heap of drill bits and Red Bull cans … you are probably in the right place!

Judy

Are You Living in a ‘Material’ World?

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When discussing RF/MW PCBs, starting with base materials seems like a logical place to start. However, the topic of advanced circuit materials is … well … complicated, especially for a single blog post. I’m sure this is obvious to you, but it took me the better part of this week to come to this conclusion with the help of Dale Doyle of Rogers Corp. and Denis Boulanger of Ventec. (Thank you both for your help, and graciousness!) In the end, I have resolved to leave the “heavy lifting” to the experts. Rogers, Taconic, Arlon, and Isola all have information-rich websites and employ amazing professionals like Dale and Denis who are invaluable resources (as are certain industry blogs).

Nevertheless, I did discover that I have a thing or two to contribute when it comes to this subject, as it is related to printed circuit boards.

There are a wide variety of high performing substrates on the market ideally suited for RF/MW applications. At Transline, we use all of them — because you specify them on your blueprints. In fact, we stock almost every part number of Rogers material, and many of Taconic and Arlon and a few Isola. We do this to shorten lead times and because approximately 60% of our business is in the RF/MW industries. Due to our fluency with these materials, I feel qualified to give you a snap shot of what happens after your order hits our shop floor.

First off, RF/MW materials act NOTHING like FR-4 materials in our manufacturing process! They don’t even behave like each other or one part number to another, or one material supplier to another. That is because they are all made differently and have unique compositions: Teflon, ceramic, duroid, PBD, hybrid mixes, and so on. Further, some are reinforced, some aren’t. Some are reinforced with crushed fiberglass, some with woven fiberglass. The highest-performing materials, with no reinforcement, can have dimensional stability issues so severe that they make your board fabricator want to start parking cars for a living.

A capable, qualified RF/MW PCB manufacturer must be a virtual guru when it comes to materials. They must be experts at knowing how each substrate brand, each composition, each part number, at each copper weight and thickness responds to … (taking a big breath) … etchant, plating chemicals, heat, lamination, moisture, and a whole host of processes met in fabrication. These laminates can be moody and fragile … nothing like good old predictable, robust FR-4. So, just as a good RF/MW engineer brings some art and magic to the science of their design process, so it is with the board manufacturer.

Why is this important to know? Because many an excellent PCB fabricator has made the innocent, though faulty, assumption that because they can make extremely complex boards with FR-4, that this RF stuff will be a cake walk. They may have even enjoyed success with some RF boards made on a specific material, but unable to succeed on another. (Shortly thereafter is when you get that embarrassed phone call informing you that they can’t make your boards after all.)

What I am proposing here is that RF/MW PCB manufacturing is a specialty, just as RF/MW engineering is a specialty within the general discipline of electrical engineering. Far too many PCB suppliers and engineers appear to lack this awareness. Why do I believe this? Because I work with RF engineers daily who have the scars to prove it! I believe this because after having 16 years of experience working with very complex FR-4 boards, and a one year working with RF/MW boards–I still feel like a rookie when it comes to RF boards. I also hear evidence from materials suppliers and buyers. I hear it from engineers on LinkedIn. It is for these reasons that I was compelled to create this blog.

So, here are a few possible solutions I hope may be helpful:

When you evaluate a new RF/MW board supplier, consider asking what percentage of their business is RF/MW, and how long they have been doing RF/MW PCBs? Which materials are they accustomed to working with? Ask questions about their quality and test records that verify their ability to successfully hold the tough impedance tolerances you may expect. Ask for RF/MW customer references. Ask your substrate rep for recommendations — in some ways, I think they have the best seat in the house, often offering some much-needed objectivity.

My advice is this: Don’t rush, headlong, into a relationship with a new supplier because they can save you 10%, because by doing so they may, unwittingly, cost you far more — like the loss of an important customer. Think more along the line of long courtship and marriage, rather than one-night stand in Vegas (a tall order when we are all so price driven!). Finally, look and listen for signs of true expertise. Look for that rare mix of knowledge, skill and experience mingled together with a twist of art and magic.

Blogs are designed for dialogue, so please offer your feedback and comments. If you have more ideas or input on this topic, please share it. We have much to learn from one another and I look forward to hearing from you!

Best wishes,
Judy

Will Cancer Warning Hang Up Cellphone Use?

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Yet another body is warning of links between cellphone use and deadly brain cancer.

The WHO/International Agency for Research on Cancer (IARC) today announced it would classify radio frequency electromagnetic fields as possibly carcinogenic to humans, based on an increased risk for glioma, a malignant type of brain cancer associated with wireless phone use. Glioma made up 2/3ds of the new cases of brain cancer identified worldwide in 2008, the WHO/IARC said.

With some 5 billion cellphone subscriptions in use worldwide however, the question is, will the decision change anyone’s behavior?

On one hand, it could lead to an increase in use of hands-free devices that keep the RF antenna away from the user, as recommended by IARC. That would mean a corresponding increase in business for electronics manufacturers.

On the other hand, most users are likely to consider this warning with the same mock seriousness they give to sunscreen. It is highly unlikely that the emerging markets, few of which have built out landline infrastructure, will reverse course and spend the billions (or more) needed to offer an alternative to cellphones.

No End for Space

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I, for one, am thrilled to see the US is not ignoring the challenges of moving beyond our humble domain on Earth.

As NASA announced yesterday, the Obama administration has given the go ahead to push forward on deep space missions. Tapped for the mission is a design called the Multi-Purpose Crew Vehicle developed by NASA and Lockheed Martin.

So much of the communications capability we take for granted today — from cellphones to satellite communications to GPS and so forth — was enabled by federal funding of bleeding-edge technology used in the space program. (And that doesn’t even begin to cover the major advances in rockets, materials science and other areas.)

Even in the midst of a severe cash crunch, the US is betting that the benefits outweigh the costs.

While some opined that it was a mistake for the Bush and Obama administrations to give up on moon landings and obsolete the Space Shuttle, the picture that is now emerging is more complete. Far from completely giving up on space travel, the US is once again putting the proverbial stake in the ground (or its celestial equivalent) and moving the bar well past where man has thus far traveled.

The electronics industry historically has benefited from NASA’s investments. Let’s hope history once again repeats.

Tin Whiskers and Toyota: Collision Course?

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New criticism of the reports by the National Highway Traffic Safety Administration and NASA Engineering and Safety Center that led the US Transportation Secretary to publicly absolve Toyota of unintended acceleration problems in its vehicles is breathing new life in what the mainstream media had decided was a closed story.

When the US agencies released their reports in February, Sec. Ray LaHood stated that the findings by the NHTSA and NASA proved Toyota’s electronics were not guilty of causing unintended acceleration. “The verdict is in,” LaHood said. “There is no electronic-based cause for unintended, high-speed acceleration in Toyotas.”

Not so fast, said Safety Research & Strategies, which this week went to press with a report condemning the earlier findings for everything from flawed analysis to conflict of interests.

In the report, SRS claims the tin whiskers found in the vehicle samples provided to NASA did in fact reveal a failure mechanism that was ignored in the NHTSA report, yet that mechanism in accelerator pedal sensor circuits can cause resistive shorts that could lead to acceleration.

The report has become a hot topic among a group of printed circuit board reliability experts, who are pointing to the “extremely small sample size” of vehicles used by NASA to perform its investigations. “There are millions of Toyotas on the road today but NASA was able to look at only a handful,” wrote Bob Landman of HRL Laboratories, on the IPC TechNet Listserv. “Despite the small sample size, they found whiskers.  The Law of Errors tells you what about this fact?  That whiskers are a significant finding.”

Landman noted that in one case, NASA found whiskers in a pedal assembly after a woman who had an incident of sudden acceleration was provided the defective assembly by the dealer that fixed her car. “She learned of the [Department of Transportation] investigation and gave them the assembly, and it found its way to NASA where [researchers] found whiskers shorting the leads of the potentiometer.

Landman also said NASA demonstrated a braking problem under a test track sudden acceleration simulation.  “A NASA driver was strapped in, a NASA passenger had two switches, one to cause sudden acceleration at 45 mph and the other to safely turn off the the sudden acceleration so the vehicle could be brought to a stop.  What happened?  When sudden acceleration was initiated, the throttle was at 100% so there was no vacuum assist and the driver, using both feet on the brake pedal, could not stop the vehicle! It was found that it would take 600 pounds of brake force on the pedal to cause the brake to slow down the vehicle. Clearly, the software does not allow the brake to override the pedal. This is a defective design.”

“Something is rotten in this [NHTSA] report, it seems to me, and SRS found it,” Landman said.

Blowing Smoke

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The deadly explosion Friday at Foxconn’s Chengdu site killed three workers and injured 15 others. Will the company, at long last, feel its workers pain?

It says here, no.

Apple, one of the larger customers for the site, released a statement that was at once nonjudgmental and noncommittal. In it, the iPad maker had this to say: “We are deeply saddened by the tragedy at Foxconn’s plant in Chengdu, and our hearts go out to the victims and their families. We are working closely with Foxconn to understand what caused this terrible event.”

Whoopee.

For a company that takes incredible umbrage at the slightest hint of disclosure, I suppose it would be asking too much for it to reveal any hint of emotion now. But Apple has long shown itself to be disinterested in the ugly goings-on at its largest supplier. Report after report has ripped Foxconn for worker abuses ranging from environmental conditions to overtime and penalties for mistakes generally associated with penal colonies.

Reportedly as much as 30% of the highly profitable iPad 2 tablets are built in Chengdu. If that’s the case, there is absolutely no reason Apple should not have an employee on site, 24/7, ensuring operations are running smoothly. This begs the question, where was that employee? Did he or she not know about the conditions in the polishing department where the explosion reportedly took place, and how workers complained “the department is full of aluminum dust” and “(e)ven though they have worn gloves, their hands are still covered by dust and so (is) their face and clothes?”

Other major Foxconn customers, such as H-P, Dell and Motorola, generally have avoided the scrutiny that Apple gets, but that doesn’t — or shouldn’t — make them any less culpable. It’s a convenient excuse to hide behind the veil of outsourcing as a means to ignore what goes on inside your supplier’s factories.

To me, it’s corporate-sanctioned cannibalism. We are supposed to be better than that.

Designer Salaries by Region, Revisited

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Some readers have asked for a more complete explanation of the data contained in Table 5 of PCD&F senior editor Chelsey Drysdale’s annual designer salary survey.

The table shows the current annual salary range by region, but due to an editing error, the salary percentages were not broken out in a meaningful way.

The graph below should help. (Right click on the graph to enlarge it.)

2 for the Show

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The early sense is Carl Icahn will win two seats on Mentor’s board. Given there are eight seats total, and that Icahn and Casablanca Capital — another disgruntled shareholder that is supporting Icahn’s slate — between them own slightly more than 20% of the EDA company’s stock, that seems pretty fair.

Whether it will benefit the company in the long term remains to be seen, of course.