A New Assembly Metric

Patty arrived at work an hour early to prepare for her meeting with ACME CEO Mike Madigan. Nineteen days ago he had asked her to develop an electronics assembly metric that would correlate with profitability. This metric would, in turn, be able to help pinpoint opportunities for improvement. He gave her 3 weeks, so she was two days early. Mike was in town to meet with Sam Watkins, the local plant manager, so he ordered that they meet.

Patty had quickly identified non-material assembly cost per I/O (NMAC/I/O) as a good metric candidate. She went to five of ACME’s plants and, after a day or two at each one, she collected all the data she needed to prove her point. Rob helped by writing an Excel macro that would calculate NMAC/I/O and plot it versus profitability. The correlation coefficient was an outstanding 0.983.

While visiting the five factories, she tried to learn why those that had a poor NMAC/I/O were performing poorly. After a little checking, she and Pete discovered that the poor performing sites typically had lines that were not time balanced, had slow component placement machines, and occasionally had very slow printers or solder paste with poor response to pause. There was even one plant that was using a full wave solder process, when only eight solder preforms would have done the job in the reflow process. None of these “problems” would show up if you were only tracking line uptime. In light of this situation, she also developed a plan to use NMAC/I/O to identify and implement opportunities for improvement.

As Patty headed toward Sam’s office, Sam’s administrative assistant invited Patty into the conference room to allow Patty to get her laptop set up. Just as she finished setting up and her Powerpoint presentation was on the screen, Sam and Mike walked in.

“Coleman, we’re counting on you to take us to the next level,” Mike said a little gruffly, “so let’s get this show going.”

Patty looked at Sam and could tell that Sam was uncomfortable with his boss’s abrupt demeanor.

“I performed quite a bit of research and concluded that non-material assembly cost per I/O is the best metric,” Patty started.

“That’s great Coleman, but what the hell is non-material whatever you said,” Madigan interrupted.

Patty’s cellphone vibrated, but she ignored it.

“Non-material assembly cost per I/O is the total cost of running a factory less the components, hardware, and PWBs used. Some people call this the conversion cost,” Patty answered.

“If you think about it, it is almost obvious that this is the best metric,” Patty went on, “as it measures all the non-material cost divided by how much we produce.”

“I get it,” said Sam. “We are producing I/Os or solder joints, we measure the total cost to make solder joints and divide by the number of solder joints. It’s that simple.”

“Precisely,” Patty responded.

“I understand now why uptime alone wasn’t a complete metric. You can be up and running, but be doing it inefficiently,” Mike said with a rare smile on his face.

Patty’s cellphone vibrated again.

“Exactly,” Patty commented.

“OK, so we are going to measure NMAC/I/O,” Mike commanded, “How does it correlate to profit?”

“It is nearly perfect,” Patty said.

They continued their discussions and reviewed Patty’s plan to improve productivity at the sites with a high NMAC/I/O. Patty would take the lead on this effort.

As Patty got up to leave, Mike commanded, “Oh, and Coleman, find out why so few people use NMAC/I/O.”

Patty thought this was something to discuss with the Professor.

As Patty walked out of Sam’s office, Clare Perkins, Sam’s Admin stopped her.

“Ms. Coleman, your mother-in-law called, Rob has been taken to the hospital,” Clare said.

HazMat: An App For That

The US Department of Homeland Security (DHS) last week demonstrated a cellphone that can detect life-threatening chemical exposures.

The device works using sensor technology made very small — but effective enough to detect, say, dangerous levels of carbon monoxide.

I was walking with my sister recently alongside her residence in Exeter, New Hampshire.  Suddenly, we thought we smelled propane.  We sniffed in widening circles for a while — not long enough to be taken away, but long enough to look silly and realize we had imagined it.

Or had we?  It’s times like those where a device is nice, or an app for your cell phone, that could solve the problem and eliminate doubt.  Such an instant detection device would curb danger to ones you care about — or ones you are are tasked with rescuing, as with a Fire or Rescue team.  In fact, Fire Chief magazine did a nice write-up about this new device.

And with that, we welcome this new device, the DHS “Cell-All,” as it’s called.  “Cell-All” is a play on the words, “Tell-All,” for those who didn’t get it at first, like me.

A spokesperson for the device said, “Cell-All detects and alerts individuals and public-safety authorities to the release of specific toxic chemicals into the environment, putting environmental threat detection within reach of anyone who has a cell phone.”

Stephen Dennis, Cell-All’s program manager, envisions a chemical sensor in every cell phone in every pocket, purse, or belt holster.

With over 85,000 unique chemicals flying around the world now in various forms and interactions, this gadget stands to revolutionize HazMat safety, and offers another level of security for those of us with propane heat and active imaginations.

Read more here.

Will Cancer Warning Hang Up Cellphone Use?

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.

Bouncing BGAs

I dropped my cellphone on the pavement the other day. That’s bad enough, but in my instinctive attempt to catch it, I actually hit it and increased its downward velocity. Luckily, everything still works. The odd thing is that I just assumed that it would still work. No real questions or doubts on that thought.

That realization got me thinking. (It happens now and then.) What other devices do I have that I automatically expect to survive a drop onto concrete? I have a carpenter’s hammer. I expect that to survive a drop intact. I would not expect my camera to survive such a drop intact, and have empirically verified that fact. A little car GPS? Probably not. Laptop; uh … no.

I’m sure there are some other devices that would easily survive. I just can’t think of any off the top of my head. I suspect that there are a lot of factors that go into making cellphones survivable. The case, the overall mass, the quality of solder joints.

Along those lines, some folks use an underfill glueish type substance to hold BGAs more securely. Some designers use pick and placeable solid underfill. Some just rely on extra good soldering and some leave it to luck. Of course, not all BGA installations require much shock resistance. How do you secure your parts when shock or vibration are serious concerns?

Duane Benson
Quick, where’s Henry? I need an inductor.