An Electronic Business Card Holder

I design and build electronics at home, late at night when the spiders are out, and by day, I put my hours into Screaming Circuits. My job here doesn’t involve building things. I’m the marketing department, but I like to keep as much manufacturing smeared all over me as is possible. Here’s one way I do that.

Benson_bizBusiness cards are a bit of an anachronism today. I don’t give out many, this being the 21st century and all, but I still need some on my desk – I guess to look businessy or something. No one’s ever given me a cheap card holder with their logo on it, and I don’t want to just scatter cards around. So, why not combine my need to display business cards on my desk with my compulsion to create electronic things? With that thought in mind, I decided to build an electronic business card holder. Of course, I first had to decide just what an electronic business card holder would be.

Here’s what I came up with:

  • It should be small, about the size of a business card
  • It should have a lot of blinky lights
  • It should do something when a card is removed
  • It should have a long battery life
  • It should use tiny parts to show off our manufacturing capability a bit
  • It should be 100% buildable within our electronics manufacturing process (meaning it should be just electronics; no bolts or case)

That’s not a long list, but does involve a few decisions. I’m pretty familiar with Microchip PIC processors, so that would be a logical choice to drive the thing. Arduino compatibility would be cool, but I’d have more trouble with battery life, and the PIC microcontrollers come in some pretty inexpensive forms.

Benson_biz2I’d recently been using a variant of the PIC18F46k22 on another project. I comes in a 5 x 5mm QFN package and can be purchased for less than $3 in small quantities. it has plenty of I/O and can be set to a very low power sleep mode. I settled on that MCU and a CR2032 coin cell battery for power.

Rather than add any extra hardware to hold the cards, I came up with an arrangement of pin headers and small push-button switches. (as in the photo below right). Benson_biz3One header is the six-pin Microchip in-circuit programming (ICSP) header, and the other is a six-pin I2C/SPI header. Not that I need I2C or SPI, but with that, you could turn this into a robot business card holder or something.

I considered a light sensor to detect when a card is being picked up, but that would require leaving the A to D powered up, and it would be less reliable due to changes in lighting. I looked around my junk box at home, and found a Freescale MMA8452 3 axis accelerometer in a 3 x 3mm QFN package. It also has a decent low power mode, and can be talked to over I2C.

Some 19 GPIO pins remained open, so naturally, I had to put in 19 LEDs.

Stay tuned for my next installment, where I’ll go through some of the design decisions. At the end of this series, I’ll be giving out 10 of these, so stay tuned to see how you might be able to get one.

Duane Benson
If you dreamed you saw the silver spaceships flying
That’s a okay. They’re RoHS compliant

http://blog.screamingcircuits.com/

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Linc’d In

I never worked directly for Linc Samelson, but it’s safe to say I wouldn’t have had a career writing about electronics design and assembly were it not for him. I certainly wouldn’t have many of my good friends.

Linc passed away last weekend at the age of 89 following a car accident. He was a lifelong entrepreneur, going from engineering college student to a career in the Navy, followed by a degree in journalism from the University of Illinois in 1948.

After some time in the electrical insulation manufacturing industry, Linc recognized the need for a trade publication. That prompted he and his father to launch, in 1955, a company called Lake Publishing, named after Lake Forest, the town north of Chicago where their first offices were.

Their startup magazine, Insulation, grew and eventually was renamed Insulation/ Circuits. The electronics trade publishing industry would never be the same.

Fast forward to 1991. At that time, Lake Publishing had relocated to a far north Chicago suburb of Libertyville. To his group of journals Linc had added a number of titles — Microelectronics Manufacturing and Testing (MMT), Hybrid Circuit Technology (HCT), and eventually Surface Mount Technology (SMT).

SMT started as a seasonal supplement to HCT, then grew into a standalone publication. And in 1991, just one year out of college, I joined the magazine as associate editor.

At that time Linc was in transition too, having sold the company to a subsidiary of Information Handling Services. (According to lore, IHS bought Lake with the idea the magazines would serve as a monthly advertising vehicle for its component catalogs. Unfortunately for IHS, no one from the corporate offices in Denver ever bothered to send the ads.)

As an owner, Linc seemed to understand the nature of people. He had a racquetball court installed in the building and tennis courts outside. On Fridays came happy hours, with a keg of beer tapped to celebrate the weekend. (This was a different era for a lot of reasons.) His employees were never going to get rich working for him, but he did invest strategically, be it in equipment or brand positioning, always making sure there was an army of staff representing the company at trade shows.

Linc married my former colleague at Lake/IHS and longtime friend Jennifer Samelson (nee Read), with whom he raised seven children. Besides his wife, Linc is survived by 16 children, 19 grandchildren and three great grandchildren. He continued working into the late 1990s.

Through the years, Linc remained a favorite topic for me and former colleagues, some still in the industry, most now out. He brought us together, and in many ways launched us on our careers. I will always be grateful for his foresight and vision.

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Mirror Mirror

A mirror can bring bad luck, it is said. In this PCB assembly challenge, it certainly did when a mirrored pad layout for a transformer made it impossible to mount the component to its intended location on the top side of a PCB in its usual orientation.

Design error: A mirrored pad layout creates orientation problems between pads and component pins; layout is for bottom-side rather than top-side mounting.

Design error: A mirrored pad layout creates orientation problems between pads and component pins; layout is for bottom-side rather than top-side mounting.

The component’s footprint, it turns out, would work fine if it were on the opposite side of the PCB, but that bottom-side installation is not possible.

Flipped upside down, the SMT transformer’s pins line up fine, except that they are facing upwards. But we can still mount the component and make a robust connection using adhesive and connecting wires.

Flipped upside down, the SMT transformer’s pins line up fine, except that they are facing upwards. But we can still mount the component and make a robust connection using adhesive and connecting wires.

The customer made a design mistake; although the pads for top-side SMT mounting of the component are in place, they are in mirror-image orientation; e.g., the pad layout with Pin 1 is intended to be installed from the bottom of the board. Consequently, it doesn’t match up in terms of orientation on the top side of the PCB unless the component is literally placed onto its back. But that means that the leads are sticking up into the air, pointing in the wrong direction.

It’s well known that a dab of epoxy can cure a host of ills, and in this case it was simply a matter of dispensing a tiny amount of epoxy onto the back of the component body, in the center, as well as onto its intended location on the SMT PCB assembly.

Mirror04

Small dots of epoxy are applied to the PCB surface and to the component body, before it is attached, the epoxy cured, and the transformer connected pin by pin.

The component is then carefully located in place upside-down and the epoxy cured. With the component robustly mounted in this manner, small wires were then run from each lead (pin) to its corresponding pad on the board’s surface.

Mirror03

It requires skillful hand soldering once the component is in place, but the connection is robust and complete.

 

Roy Akber

www.rushpcb.com

Roy@rushpcb.com

 

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Conductive Inks vs. Nonconductive Inks – Part II

In the first half of this column, we began a discussion of the pros and cons regarding the use of conductive inks versus nonconductive inks to fill vias. The images below show cross-sections of a via-in-pad with nonconductive ink on the left and VIP with conductive ink on the right.
 

Via-in-pad (VIP) filled with conductive ink.

Via-in-pad (VIP) filled with nonconductive ink.

Via-in-pad (VIP) filled with conductive ink.

Via-in-pad (VIP) filled with conductive ink.

 In that column, we discussed a design that required a nonconductive ink in the through-hole via and conductive ink in the blind via. Now we ask, what were the drivers behind this decision?  Why would one use two different types of inks in vias in the same PCB, and why conductive vs. nonconductive ink? The answers are actually a bit more complex.

Copper plating is one factor, as an example. For years it has been generally accepted that copper plating is not a viable substitute for ink (conductive or nonconductive) to fill a through-hole via, buried via, or blind via. It was believed that to plate a via shut and to cover the surface with copper would take “forever,” relatively speaking, if it could be done at all.

One reasoned that not only would the process of plating the via shut with copper be prohibitively time-consuming, but even if it were technically possible to fill the hole with plated copper, the unwanted consequence of plating so much copper in the hole would result in excessive “button” or surface copper height that would lead to other defects and/or reliability risks.

Blind via plated shut with copper.

Blind via plated shut with copper.

Nowadays there are several efficient processes for copper plating to fill vias; two of these are pulse and DC rectification. Some require button plating, a two-stage process; others have evolved to the point where a single-stage panel plate will fill certain via structures while depositing less material on the surface, thereby leaving a manageable surface copper thickness. In this way, one can continue to produce a high-density product without the need for a secondary ink-filling operation.

Further, there are solutions to filling micro, blind and buried vias that require no additional process time or steps; e.g., resin or B-stage fill. The consensus was that it wasn’t possible to do this reliably. While conventional prepreg (B-Stage) historically struggled to fully and consistently fill vias, there are now specialized prepregs and bonding materials specifically engineered to do just this process reliably.

One laminate company produces a series of FR-4, lead-free, polyimide, low-loss and other high-performance laminates and prepregs.  Within their product line they offer a sub-set of prepreg (B-Stage) called the VF-series (whereby VF is an abbreviation for via fill).

Via Fill (VF) prepreg product, where core and prepreg are combined to create a pure, homogeneous material package.

Via Fill (VF) prepreg product, where core and prepreg are combined to create a pure, homogeneous material package.

 

Where we have the instance of a buried via filled with one ply of VF material, the blind via is fully filled with resin, and the dielectric distance between outer foil and inner sub assembly is very uniform. In this case, the VF matches the family of core and prepreg it is combined with, so that it permits the creation of a pure homogeneous material package, eliminating the need for a hybrid material / laminate package. The VF prepreg has been engineered for enhanced rheology and filler content so that during the lamination process the blind and buried vias found in a sequential lamination sub assembly will be fully filled.

VF Prepreg is just one example of available materials designed to fill vias during the lamination process, thus eliminating the need for a secondary operation. What process and material should you use? To make the best decision, you need to understand not just what result you want to achieve, but why.

Not long ago I had an application involving a customer’s requirement of a specific brand of conductive ink to fill a small through-hole via. The assembly was a double-sided PCB on a relatively thin (0.010″ thick) PTFE/Teflon material.

The ink-filling process requires a planarization or sanding operation after the ink is cured in order to remove excess ink from the copper surface. The planarization process always includes some inherent risks and/or limitations such as:

  • Dimensional distortion of the panel of PCB material.
  • Imprecision, resulting in uneven copper thickness and poor control of circuit etching.
  • Reduced peel strength of the surface copper.

In this case, all these negative aspects of planarization were amplified because the material was a soft; thin Teflon with RA copper. This material is highly unstable to begin with and susceptible to distortion.

The PCB manufacturer struggled to meet the customer’s requirements, but excess cost, time to produce, delays, and lower yields resulting when compliant product was finally produced were a real problem, prompting further discussion with the customer.

A breakthrough occurred when we began to ask why we were using certain materials and questioned the necessity and benefit of each step in the process. We realized that the via filling; i.e., the specific material requested by the customer, was being used to prevent solder from flowing through the vias during assembly. But what else was it there for?

After critical examination, we realized:

  • That there was no need for conductivity in the filling material , let alone any reason for it to be limited to the customer’s specifically preferred ink material.
  • There was no need for a copper pad to be plated over the surface of the material or via, since nothing was being soldered on top of the via.
  • There was no need for a specific brand of ink material.
  • Alternative materials and processes could therefore be explored.

After all, we began to examine the real purpose that the via filling was intended to address, and more importantly, what it was not there for. The material had been used, all along based upon a group of assumptions that, when examined, weren’t true and did not justify the use of that specific (and costly) ink material. Its use simply could not stand up to challenging questions, such as added reliability, electrical advantages or mechanical aspects or even thermal characteristics or properties. It contributed to none of these justifying criteria.

 

Buried via fully filled with resin; note that the dielectric thickness between the outer foil and the inner subassembly is very uniform.

Buried via fully filled with resin; note that the dielectric thickness between the outer foil and the inner subassembly is very uniform.

In summary, when evaluating a new product, manufacturing process, etc.:

  • Challenge any long-held assumptions.
  • Gather information from multiple sources.
  • Qualify that what you have been told by others is really best for your needs and not skewed merely to support the choice of a specific product.

Manufacturers must talk with the designer to understand what designers really want to accomplish and why. Designers must speak with manufacturers in order to understand the intricacies of the process. Finally, as technology evolves and more innovative solutions for emerging applications or enhanced solutions for existing ones are found, cooperation and collaboration are the keys to optimizing decisions and selections.

Roy Akber

www.rushpcb.com

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Surprised, Part II

Headline: “Indian Officials Questioning Foxconn Investment Plans

Surprised?

(I’m not.)

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Surprised, Part I

Headline: “IEC Swings to Q1 Profit”

Surprised?

(I’m not.)

 

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Conclusion of In Electronics Manufacturing, Does Cpk =1 Yield 66,800 DPM?

Patty, Rob, and Pete were quite sure they understood the confusion in the Cpk = 1 issue, but wanted to make sure they discussed it with the Professor.  After a brief chat with him, they called ACME CEO Mike Madigan from The Professor’s office.

“Professor, it’s great to speak with you again,” Madigan began.

The all exchanged pleasantries, with the Professor thanking Madigan for his financial support of Ivy U through the ACME Corporation.  In a few moments the discussion turned to the Cpk = 1 issue.

“Tell me what you amazing intellectuals have figured out,” Mike chuckled.

“We all thought the article that the vendor referred to had a great discussion on statistical process control (SPC)”, Patty began.

“We especially liked the discussion on the difference between a process being in ‘control’ and ‘capable,’” Rob added.

“But, what about 66,800 ppm equals a Three Sigma process?” Mike implored.

“As we know, Motorola started the ‘Six Sigma’ movement,” the Professor began.  “They defined ‘Six Sigma’ quality has having a Cp of 2 and a Cpk of 1.5.  True mathematical Six Sigma is Cp=Cpk=2.  Their definition, with a Cpk = 1.5, allows for a shift in the mean of 1.5 Sigma.  The adage that ‘Six Sigma’ equals 3.4 ppm defects comes from this definition.  Because of this shift, most of the defects are on one side of the distribution.  By the way, true mathematical Six Sigma is about 2 defects per billion,” he went on.

“It seems a little like cheating to me,” Madigan added.

“Me too. I think they wanted something sexy sounding, like ‘Six Sigma,’ but knew they couldn’t really achieve less than 2 ppb defects, so they created the 1.5 sigma shift of the mean,” Pete chimed in.

“I’m sure that others agree with Pete, but that is where the world of ‘Six Sigma’ is.  Unfortunately, it can create confusion – as in the case at hand,” the Professor responded.

“So how does it relate to the 66,800 defects per million equaling a Cpk of 1 and a Three Sigma process?” Mike asked.

“Pete has done the most work on this. Let’s let him answer,” the Professor suggested.

“If you apply the 1.5 Sigma shift of the mean to process capabilities, we get the table below,” Pete said.

lasky table

 

 

 

 

Note that the Cpk level for 66,800 dpm is 0.5 not 1 and the true process level is not Three Sigma, but 1.5 Sigma.  Admittedly the Cp level could be 1, but Cpk is a precise calculation and the graph from the paper in question (reprinted below) has it wrong.  The values they list for Cpk are the Cp values.  This is the mistake your vendor made by using this chart. ” Pete said.

lasky figure

 

 

 

 

 

 

 

 

 

“The graph below shows the situation for the vendor.  Distribution A has a Cp and Cpk =1, where as distribution B has a Cp = 1, but a Cpk of only 0.5.  The 1.5 Sigma shift for B is also shown.  The vendor’s data are similar to B, with its the 66,800 dpm..  It is improtant to note that Cp alone tells nothing about the defect level,” Pete went on.

lasky figure 2

“Pete, please tell Mike about the spread sheet you made,” Patty suggested.

They had signed onto Webex, so Pete gave a limit demo.

“By entering the spec limits, as well as the mean and sigma of the data, it will calculate Cp, Cpk, the sigma limit of the process, and the process dpm,” Pete said.

 

“Oh, and you can enter the dpm and it will estimate the Cpk and process sigma level,” Pete went on.

“Quite impressive,” Madigan summed up. “I assume it is OK if my team uses it?” he went on.

“Sure,” Pete said, beaming a little.

Math was never Pete’s strong suit. But, being at Ivy U, he had recently taken a statistics and calculus class. He had a strong sense of accomplishment after creating this useful spreadsheet.

For those who would like a copy of Pete’s spreadsheet, send me an email at rlasky@indium.com.

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Wooden Thinking

Were you as shocked as I was Saturday when Sparton announced CEO Cary Wood had resigned?

Since he took over as president of the company in 2008 (he was named chief executive months later), the 48-year-old Wood has been a shining star in the EMS sector. He reshaped and reinvigorated Sparton. In 2006, the company’s sales were just over $170 million and the company was in dire need of restructuring. By 2011 it had turned the corner, and today sales top $430 million, with consistent profits. He led the buyouts of Electronic Manufacturing Technology, Onyx EMS, and Hunter Technology, among others, firming up its presence in the medical and defense markets.

The reason(s) for Wood’s sudden departure are murky. Sparton isn’t talking, although it did praise (albeit somewhat tersely) his contributions. The rumor mill is speculating the move was prompted by an exchange on the firm’s quarterly conference call last Wednesday between Wood and some hedge fund managers who felt the company should be far more valuable for shareholders and even suggested a breakup would be in order. One went so far as to say his “16-year-old daughter and small pack of Norwich Terriers could probably get the stock up 50% to 100% before the end of the quarter.” (Cue to the 27:50 minute mark for the quoted assertion.)

Another frankly asked why a couple Sparton customers are considering moving production in-house.

To his credit, as the exasperated fund manager called for the board buy back stock or step aside, Wood kept his cool throughout. He noted that the board has evaluated all the alternatives about how to deploy its capital, put a pause on M&A and is moving to optimize SG&A and performance.

This exchange gets at one of the tensions inherent in being a public company today. The market is controlled by institutional and hedge fund investors, not private citizens. It’s a cliche, but the goals of a short-term investor are fundamentally different than those of a manufacturer, especially one that generates a big chunk of its revenue building other companies’ products. There’s a fundamental disconnect between needing to invest for long-term survival and trying to squeeze the last bit of blood from the body before moving on to the next victim. Yet coming up with the financing to fund expansion and acquisition without ceding near-total control of the company can be near impossible without going public.

Sparton has spent north of $150 million in EMS related acquisitions in the past eight years, including $55 million for Hunter Technology last year. It is exceedingly difficult to live in the $100 million to $300 million or so market in the EMS industry today.  Companies have to grow, and they typically have to come up with revenue streams beyond just soldering components.

Sparton is in better shape today than when Wood took over, and there’s no reason to think that will change in short order. But the industry needs to take pains to protect its good managers, because just building things well isn’t enough for long-term success these days, at least not for public companies.

Addendum: Here’s a link to a Crain’s Chicago Business article on Wood’s departure.

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Raspberry 6.283185307 Zero

AKA a second post on the Raspberry Pi Zero.

It’s been two months since the release of the $5 Raspberry Pi Zero, and I still haven’t been able to buy any. As I discussed in my prior blog about it, there is plenty of discussion around the fact that, out of the box, it’s not real useful without adding enough accessories to make it as expensive as any other Pi model. I certainly understand that point, but here’s another way of looking at it.

If you want to learn software, buy one of the other Pi models. If you want to learn about hardware design, buy the Pi Zero and download some CAD software. Then go online and get the Pi Zero dimensions and start designing accessories for it. You can start with one of the many open source Pi Zero accessory designs, or come up with your own. Don’t look at it as a system that’s missing too many parts. Look at it as a base for a different type of learning.

One of the scariest things about designing a plug-in/on board for a bigger computer is the possibility of a mistake that will fry the expensive board. With the Pi Zero, you’re risking $5.

Like I said, I still don’t have one, but I’ve drawn up my for Pi Zero accessory:

Benson_Pi

It will plug right on to a Zero as a rechargeable Li-Poly power supply. Not at all a complex circuit, but it’s only the first in a series. As a small board, it doesn’t cost much to get fabbed, so for about the price of one PCB sized to fit the bigger Pi boards, I can get two of these.

Next, I’ll design a motor driver, and then possibly an IMU, or sensor board.

Duane Benson
If you have your Pi calculate Pi, would that Pi be Pi enough for Pi?

http://blog.screamingcircuits.com/

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In Electronics Manufacturing, Does Cpk =1 Yield 66,800 DPM?

As Patty was walking past the Professor’s office on her way to see Pete and Rob, she decided to drop in.

“Professor, I got the strangest phone call. A man claimed he had invented a machine that could create energy,” Patty began.

“Tell me about it,” the Professor chuckled.

“Well, he correctly noted that, when he took his kids to the beach, a submerged beach ball pushed up with a lot of force. So, he developed a technique to extract the energy produced when the ball is released,” Patty explained.

“Let me guess,” the Professor offered. “He then developed a technique to continuously extract energy; an energy producer of sorts.”

“Exactly! How did you know?” Patty responded.

“Well, I have been here about 40 years, and I have had forty such calls,” the Professor said.

“Tell me the details of your call,” he continued.

“There would be a box of small mass with a generator and pump inside; the generator and pump occupying little of the volume of the box. The box would be filled with water at the top of a lake and would then would sink to the bottom. Once the box was at the bottom, the water would be pumped out and the buoyancy would cause the box to rise. A rope would guide the box on its up and down journey and the generator would spin as it travels up the rope, hence generating electricity. The cycle would be repeated over and over and, in a sense, become a power plant,” Patty explained.

“And the problems are?” the Professor asked.

“I told him that it violates the laws of thermodynamics, and that I could make some calculations that would show that it would not work. Basically, the amount of energy required to pump the water out is greater than what the buoyancy would generate, considering friction, etc.,” Patty replied.

“His response?” the Professor led.

“My sense is that he thought he could make it work, in spite of the physics,” Patty answered.

“In my experience, that is always the response. Probably my most troubling experience was a chap who convinced a small venture capital firm to advance him about $3 million. He had a machine that, he claimed, continuously extracted energy out of the earth’s magnetic field. The biggest shock to me was that the leader of the venture capital firm was a graduate engineer who had retired as COO of a Fortune 50 company. I still haven’t figured out how such an accomplished person could not see that an energy-producing machine is not possible,” the Professor expounded.

“What was the upshot of all of this?” Patty asked.

“Well, they didn’t pay my consulting fee when I explained how it couldn’t work,” he chuckled. I checked a few months ago and the company’s website is down,” the Professor replied.

“The people that are into this folly don’t even realize that, if an energy-creating machine could be made, it would be the greatest discovery in history,” the Professor went on.

After a few more minutes of this discussion, Patty resumed her short walk to Pete’s office. Rob was already there.

“Looks like Mike Madigan needs us again. Did you see the email he sent us?” Pete asked.

“No, what’s up?” Patty and Rob said in unison.

“Something about Cpk,” Pete answered.

Patty reached for the phone to set up a conference call to Mike.

As she dialed, Patty admonished, “Now remember you two, good manners. No laughing at any of Mike’s questions.”

“Yes, ma’am,” Pete and Rob said in unison.

Mike’s secretary answered and said she would put them right through.

After a few pleasantries, Mike got to the point.

“Remember the tolerance analysis and specification that you did for passive resistor and capacitor length?”  Mike began.

“Yes. We were all involved in that project,” Patty answered.

“So, it is a Cpk = 1, or a Three Sigma spec, right?” Mike asked.

“Sure,” Patty, Rob, and Pete answered in unison.

“So, what percent of parts should be out of spec?” Mike asked.

“Let’s see … Three Sigma is 99.73% of parts in spec … so that would be 0.27% out of spec,” Pete calculated.

“Well, they are shipping us 5% out of spec parts and claiming they are better than Three Sigma, or a Cpk of 1, because they used a recently published graph, that said a Three Sigma, or Cpk = 1, process was 6.68% of parts out ot spec. I just sent it to all of you,” Mike said.

Pete opened the email and showed it to Patty and Rob.

“I’ll be darned! It does say that a Cpk = 1, or Three Sigma, has a defect rate of 66,800 defects per million or 6.68%,” Rob groaned.

“I’ll bet it has to do with the definition of ‘Six Sigma,’” Patty opined.

A look of recognition came over Pete and Robs eyes.

“What do you mean by the definition of ‘Six Sigma?’” Mike asked.

“We have all heard people claim that ‘Six Sigma’ is 3.4 ppm out of spec. Actually that’s a 4.5 sigma process. This definition allows a drift in the average of 1.5 Sigma that knocks the Cpk down to 1.5.  True Six Sigma is a Cpk = 2 and is 0.002 ppm parts out of spec,” Patty replied.

“I’m a bit confused. But, let me show you some of the length data for 0402 passives,” Mike said.

“We measured them metrically so the length should be 1mm +/-0.1, Three Sigma.  Instead, it is more like 1mm +/-0.1, Two Sigma. That’s a little more than 5% outside of the spec,” Mike continued.

A Minitab Analysis of the 0402 Length Data.

“Give us some time to sort it out,” Patty suggested.

Is a Cpk of 1, or a Three Sigma, process really 66,800 ppm (6.68%) out of spec?  Will Patty and the crew figure out what’s going on?

Stay tuned…

Cheers,

Dr. Ron

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