Circuits Assembly blog

A little extra checking may take a little extra time, but it can save a lot in the end. This sort of thing just bums me out. I’ve done it and similar things a few times myself. I’ve used a library for a connector with the same footprint, but smaller diameter pins than my chosen connector. That was a bummer too.

My best guess is that it’s a 0.1″ (2.54 mm) spaced footprint on the PCB and a 2.5 mm pitch part. It almost works. You might not even notice if it were a three or four pin part. At six, you’d certainly notice and at something from there on, the part simply will not fit.

In a prototype world, you may be able to get away with bending the pins a bit and forcing them a little way in, but maybe not. In a production electronics manufacturing environment, most certainly not.

Duane Benson
In the world according to Google, it’s only 72,000 beard-seconds off.

http://blog.screamingcircuits.com/

I think this one has both some land pattern issues and some schematic issues. It’s unfortunately pretty common to see footprints that are close, but not close enough to work. Looking at the data sheet here, there may be a schematic issue as well. The only connections on to the part on this board are ground and P3. I don’t know the part, so I suppose it’s possible that all it needs is P3 and ground, but it looks more like a case of the footprint being wrong and the pin connections being wrong. Pins 1, 2, 3, 5 and 7 are all ground, but on the board, 1 and 3 go some place else. Bummer.

Making custom CAD parts can be pretty annoying and it seems to be a function disproportionately prone to error. Why is that?

Duane Benson
in horse shoes, hand grenades and sometimes atom bombs

http://blog.screamingcircuits.com/

Patty and Pete were able to squeeze in nine holes of golf, although it was stressful for Patty. Pete was a good golfer, but not in Patty’s league; he typically shot in the low 80s for 18 holes compared to Patty’s 68-72 range.

Today, going into the 9th hole, Patty was even par and Pete was one under. He was teasing her relentlessly.

The ninth hole was 532 yards long. Patty used all of her recent training and focused as she drove the ball. Her swing speed hit 114 mph and with a 4 mile an hour tailwind, her drive was 291 yards, 30 yards beyond Pete. Her second shot, with a five wood was 12 feet from the pin. Her putt was dead center for an eagle, Pete’s 8-foot birdie putt lipped out of the hole. Whew! She beat Pete by one stroke! Pete was still thrilled that he gave Patty such a close call.

As they left the golf course, Pete said, “John is really working miracles at the factory, given the constraints he is working under. He has developed a disciplined approach to changeovers and uptime, and has eliminated most waste. But the factory really needs to be cleaner and more organized. With all that is on his plate, and no cleaning staff, he will have trouble implementing a 5S. It will be hard to win new customers with the place looking like it does.”

The next morning, as they prepared for the meeting with Oscar Patterson, Patty noticed that John’s color was ashen.

“John, are you alright?” Patty asked.

“You’ve never been in a meeting with Mr. Patterson. He can be a bit … uh …. difficult,” John stammered.

“From what I hear he is a ruthless, brutal dictator,” Pete added.

John did not disagree.

Patty thought it might be best to call back to her site GM to clarify her mission.

The GM told her, “This guy is a blowhard. It would be great if you could review with him your findings and get his buy-in. But, don’t take any grief from him. He forgets that he sold us his company. Now he has a boss, and it is me. I told him you were going to perform an audit and I want him to work with you.”

So Patty, John, and Pete went to Oscar Patterson’s office to review their findings. Patty was immediately intimidated by him. He was a huge man, with a ponderous stomach. But the posters in his office were the worst. One read “I’m the Boss, you aren’t.” Another read, “My way or the highway.” Then she saw, “The Golden Rule of Management: Whoever has the gold makes the rules.” The last one she took time to read was especially troubling: “It’s a question of mind over matter: I don’t mind and you don’t matter.”

Patterson spoke first, “Let’s get this over with, I don’t have time to waste on this nonsense. I’m the boss and I’m responsible for profits, so give me your crap and get out of here.”

The Professor always advised Patty that after an audit it is best to present the strengths first and then the problems. However, never call the problems “problems”; call them “opportunities for improvement.”

“I learned this from my colleague Joe Belmonte,” The Professor told her. She had since met Joe at a few trade shows and was impressed by his wealth of experience and in-depth knowledge of assembly processes.

She started by discussing the very good 25% uptime, and the fact that the operators were quite good at changeovers. Pete had pointed out that the operators told him that John was responsible for both of these successes. The operators liked and respected John, but realized he had a tough job working for Patterson.

As imagined, Patterson warmed up to this compliments.

“I told ACME management that buying my company was a good deal. We cut costs and I am able to make a profit even though I have losers like John working for me,” Patterson bragged.

Patty was furious at this comment. Pete looked like he was going to jump across the table and take a swipe at the “Big O.” John just sat there looking defeated.

“This isn’t as bad as I thought it would be,” boomed Patterson. “Continue.”

Patty then reviewed the 7 mudas. She had been surprised that the company did quite well in this part of the audit also, undoubtedly attributable to John:

1. Overproduction
2. Unnecessary transportation
3. Inventory
4. Motion
5. Defects
6. Over-Processing
7. Waiting.

Hence, Patty’s comments were positive on this topic.

“You’se guys aren’t so bad,” boomed Patterson. “I told you I was good at generating profits, even stuck with a dufus like John here,” he finished.

At that comment, Pete’s faced turned the most crimson Patty had ever seen.

Patty then went on to “Opportunities for Improvement.” She thought she would start with 5S.

“We performed a 5S audit of your facility. This manufacturing philosophy consists of:

1. Sorting
2. Set in Order
3. Shining
4. Standardizing
5. Sustaining the Improvements,” she started.

“As ACME strives to get more customers for our contract manufacturing services, 5S is an important consideration, as many of our current and future customers practice Lean and especially 5S at their facilities,” Patty added.

As she went on, she reviewed the lack of order and cleanliness in the facility. She had photos of dried solder paste on the stencil printers, the flux and dust “stalactites,” and several other examples of 5S violations. Patterson’s face soon matched Pete’s in its level of sanguinity. But he said nothing.

Patty then volunteered that she and Pete would work with John and his team to implement a 5S if desired.

Patty could see Patterson was ready to blow, but she felt she must go on. The only topic left was turning off the nitrogen in the wave soldering machine. As Patty played the wave soldering video, surprisingly, Patterson seemed interested.
She continued, “We think an opportunity for improvement would be to reinstate use of nitrogen in the wave soldering process. First-pass yields have dropped from 94% to 87%, thus increasing rework. Or, perhaps, implementing a more robust wave solder flux. I contacted a wave flux vendor and I have some recommendations.”

At this Patterson became even redder in the face, in a rage he grabbed Patty’s laptop and threw it on the floor. Instinctively Pete dove for the laptop, spun around and inserted his chest between it and the floor. Patty had never seen such agility in a 45-year-old man.

“You bozos are worse than John the clown here!” he shouted, as he gestured toward John.

Patterson then kicked the trio out of his office. Pete was ready for a fight, but John and Patty, both visibly shaken, held him back.

Patty immediately called Sam, her GM, and told him in detail their findings and what happened at the meeting. She gave a good impression of what John had accomplished in spite of Oscar Patterson.

“Wow! Patty, I’m so sorry. I didn’t expect it would be this bad. I’ll change my schedule and fly there today. This situation will not stand. Why don’t you and Pete take a break and meet me for dinner at Dinardo’s at 7 PM? Bring John with you.”

Patty was glad that she backed up her files the night before, even though it looked like her laptop was fine.

Colonial Williamsburg was only a 45-minute drive away, and it was just 10 AM. Taking Sam’s advice to “take a break,” she and Pete drove away and toured this beautiful living museum. They also had lunch at the Trellis.

Surprisingly, with the Williamsburg respite and all of the walking Pete and Patty did, they were more relaxed and hungry than they thought they would be.

On the way back to Dinardo’s, Patty asked Pete, “How did you save my laptop? I’ve never seen such an agile, athletic move.”

“Twenty-nine years of beach volleyball,” Pete answered. “I was good enough that I tried out for the Olympics in ’92. Humbling experience,” he added.

About 10 minutes before they arrived at the restaurant, Patty’s mother called with updates on the wedding plans … only 10 weeks and counting!

John had arrived early at the restaurant and Patty and Pete met him. He looked nervous.

“John, how’s it going?” asked Pete.

“It’s hard to be optimistic,” John answered.

On that note Sam walked into the restaurant.

“This must be John Davis, the new GM, having replaced Oscar Patterson,” Sam stated with great cheer.

The words didn’t seem to register with John. “Congratulations John, well deserved,” Patty and Pete chimed in.

In the few days they were there, Patty and Pete had grown quite close to John. As the information sank in, tears welled up in John’s eyes.

“Do you think I’m up to the job?” he asked.

“John, you are already doing the job,” Patty answered.

Epilogue: Sam had felt it best to have the police accompany him to see Oscar Patterson with the news that he was fired. Patterson became so agitated that the police had to threaten to arrest him before he calmed down and was escorted from the facility.

With John at the helm, the “shop” was not recognizable in 3 weeks, as he implemented a 5S program that he designed with Patty and Pete. He performed some DoEs to find a wave solder flux that could perform well, without nitrogen, for most of his applications. However, he still used nitrogen for a few boards that had a large thermal mass. All of these, and the many other decisions he made were data driven.

Have you performed a Lean audit of your facility? Do you regularly practice 5S and look to eliminate the 7 mudas? Are your decisions “data driven” as John’s are?

Cheers,

Dr. Ron

I recently received an email comment about my blog writing that I think does a very good job of illustrating one of the frustrations that many design engineers face.

“Please have someone teach Duane the difference between “then” and “than”. It really makes him look dumb, and I very much doubt that Duane is dumb. It’s just painful see these everywhere in his blog. regards“

I’ve also been called out on “it’s” vs. “its.” At least, I seem to mostly have the “to”, “too” and “two” down. Now, I’m a reasonably educated person and writing is a significant part of my job, so you would think that I wouldn’t fall into traps like this. Undeniably, I do. It drives me nuts. I even have a couple of websites that I refer to (when I think about it) to help with such things. Site one and site two, but obviously I still fall into the traps.

So, how does that relate to the frustrations of a design engineer? Well … read my blog. Most of my writing is about a very similar issue. Check this one about via in pad. And this one about parts libraries. Or this one about shorting potential under a QFN.

None of those problems was created by “dumb” people. Likely, all those boards were created by intelligent, highly skilled, well-trained engineers — people who got picked on in school for blowing the curve, or were called “Spock” by kids not on a college track. Yet, what does such an error get? It may get a blog post here. It may get a Twitter comment like this that I wrote about. Of course, some times silly little oversights like this have more dire or more expensive consequences.

And the moral of the story — attention to detail and continuous learning. Never stop trying to learn. Never stop double-checking. I have to refer to my two grammar sites and other references. If you’re a designer, never stop researching. Dig into those data sheets. Read up on best practices. If you’re working a job over multiple sites, always make sure everyone’s using the same rules.

Over the next few days, I’m going to go back through my past posts and see how many of these “than/then” errors I can find and rework. Ugh.

Duane Benson
Never give up. Never surrender.

http://blog.screamingcircuits.com

My latest  presentation, made to the SMTA Long Island chapter, was on how to use software tools that avoid destroying your PCBs during the profiling process.

Are Toyota’s gas pedal failures caused by a breakdown in the electronics system? And if so, are the much-publicized recalls tied to a lead-free problem?

That’s been the hot topic on the TechNet email forum for over a week now. The mainstream media, of course, has gotten hold of the issue too, and is running with it like a Camry with a stuck gas pedal.

Here’s a list of some articles to date:

• MSNBC is considering the likelihood of an issue with the electronics sensors.
• The Los Angeles Times notes that the electronic throttle system uses sensors, microprocessors and electric motors, rather than a traditional link such as a steel cable.
• AOL Autos and Autoblog look at a recalled pedal and discuss how possible sources of the problems.

Bob Landman, a reliability expert and a Life Senior Member of IEEE, has been vocal that the connection between lead-free solder and tin whiskers is both real and potentially deadly.  He asserts “the increased use of electronics in automobiles when mixed with RoHS can make for a deadly cocktail. We don’t know what the causative agent [in regards to the Toyota recalls] was, but I have heard recently of brand new autos showing up at dealers that will not start.  That cause has been linked to tin whiskers.”

We do not yet have enough information to determine whether tin whiskers or even lead-free solders are to blame. One would hope Toyota would come clean about the true cause, if indeed it can be determined, so that the industry at large can learn from their mistakes.

UPDATE: Toyota today stated the cause was not electronic in nature.

Yeah, yeah. Top 10 predictions for the new year really need to be out in either the last week of the prior year or the first week of the new year. But I’m late. It’s because my oatmeal is lumpy and I’ve just been trying to decide if I should have a top predictions for the new year or for the decade. Some people would say that we’re still in the old decade, because, you know, 1 – 10. But I say, it’s only analog jockeys that say that. Digital drivers go from 0 – 9 (or 0 – 1 or 0 – F or 0 – 7… now I’m confused again. Not many go 0 – 7 these days). For the purposes of this document, I’m claiming to be more digital than analog, so the new millennia started in 2000 and this new decade starts now. Or, does that mean that the new millenia should start in 2048? Or, rather 0×800? Crud. That’s not a thousand. Okay, I don’t want to wait until 4096. I might be dead by then. Fine. It’s the year 3732. I have my handy 74LS90 and I’m going to count out my top 10 predictions.

Starting at count 0, with Qa = L, Qb = L, Qc = L and Qd = L:

0000: By the end of the decade, 50% of all passives will be embedded passives and 20% of all PCBs will have 90% or more of their passives embedded.

0001: By the end of the decade, Quad stack POP (package on package) will be commonplace.

0010: By the end of the decade, Each individual human will have their own IP address. Several of us will have more than one. That way, we can jury rig accelerometers into our hands and feet so we can wirelessly know where each of our extremities are at all times. Cats will have them too.

0011: By the end of the decade, solder paste will be used less often than not when assembling components on to PCBs.

0100: By the end of the decade, nearly all hydraulics and pneumatics in new motor vehicles will have been replaced by electrics.

0101: By the end of the decade,the first semi-autonomous passenger vehicle will be on display on the auto-show circuit. Hobbyist built semi-autonomous cars will already be on the road.

0110: By the end of the decade, “airline pilot” will generally be a really, really, really boring job. That’s a bit of a problem.

0111: By the end of the decade, most military “foot action” will consist of two soldiers in command of a squad of robots and those two soldiers will as likely be in Fort Lewis, Washington as in the combat zone.

1000: By the end of the decade, the president of the US will be promising health care reform as the highest priority.

1001: By the end of the decade, routine bioengineering will be, well, routine. Very scary.

1010: By the end of the decade, the 2019 recession will be looming large and all of the people that have forgotten about the 2009 recession and the 2001 recession and the 1985 recession and the 1975 recession… will be freaking out again.

1011: By the end of the decade, lead will be gone from 98% of new electronics. Bummer.

1100: By the end of the decade, four of the substances that replaced the substances removed from electronics due to ROHS and similar regulations will have been found to be significantly more harmful to the environment and the people recycling the materials than are the substances that they replaced.

1101: By the end of the decade, the world of intellectual property will be in even more of a mess than it is today. Virtually everything will be accessibly for easy theft and cheap replication. (This is pretty much a big “duh.”)

1110: By the end of the decade,building your own mutli-purpose robot will be as easy as building your own PC was in 1988. Hardware components and operating systems will be off the shelf, but standards will be pretty loosely defined, interoperability will be more theory than reality and applications will be sketchy and buggy.

1111: By the end of the decade, still no flying cars and personal jet packs, dadgummit!

Duane Benson
Sorry. I didn’t have a 74LS90. I only had a 74LS93

http://blog.screamingcircuits.com/

Earnings announcements came out this week for Flextronics, Sanmina-SCI, CTS, Celestica, Key Tronic, IEC and a few others.

I’ve been listening to the quarterly analyst briefings, and it would *appear* that most of the major EMS companies don’t plan any earth-shaking M&A activity.

Most are taking the approach of Celestica CEO Craig Muhlhauser, who said they would focus on areas like health care where they don’t have tremendous established depth. Flextronics CEO Mike McNamara didn’t even raise the subject. Neither did Sanmina chairman Jure Sola.

And congratulations to CIRCUITS ASSEMBLY EMS Company of the Year Key Tronic on yet another profitable quarter. That’s six straight years, and counting.

I have it on very good authority that Universal Instruments began turning a profit during the third quarter last year and is now doing much better in terms of customer demand and operations.

I have personally noted some recent wins — in some cases, orders for several machines at a time — that support the notion that their business has turned up. As the only American-based manufacturer of placement equipment, I hope this streak continues.

I’m still fiddling with my mbed. Although, I haven’t put it to real use yet. I’ve got some ideas, but I just don’t have the time these days. One of the nice things about its programming system is that if I do have to step away for a while, it’s easy enough that I don’t have to go through any kind of learning curve again. The plug-and-go USB programming and online IDE is that easy.

Contrast that to one of my little PIC based boards. I recently wanted to do something with one that I hadn’t used for a while. I dug it up and pulled out my programmer. I somehow ended up with two different versions of the programmer software installed on my computer, and I had to try both. My programmer uses the FTDI USB/serial chip, so I had to try and guess which COM port to set my programmer software too.

Six permutations later, I had that figured out. I then loaded up an old known-working hex file and took my best guess at what the fuse settings needed to be and guessed wrong. Tried again and guessed wrong. Tried a dozen different combination and gave up and dug up the PDF of the data sheet. Once I found the setting and translated them to the language used in my programmer’s software, I finally figured it out and got it all working.

Granted, if I were using this every day, I wouldn’t have forgotten all those silly little details, but think about someone learning for the first time. Or, consider a hardware engineer that rarely uses microcontrollers. Once a year or so, some design does need a controller and some programming. I’m a big fan of PICs, but the programming system for many of them seems pretty archaic compared to a product like the mbed.

Duane Benson
I need gravy for the mashed potatoes in yesterday’s post

http://blog.screamingcircuits.com/