Dr. Lasky's Blog

Folks,

I was in the Dartmouth College computer store in 2004 or 2005 and I saw a signed that proclaimed: “After July 1^st computer services will no longer support Apple Macintosh.”

By 2008, however, I noticed more and more of my students using Macs. This trend was important to me as I use Minitab® software in two of my classes. Newer versions of Minitab only support Windows.

This year, so many of my students use Macs, that I have to hold the classes in which I teach Minitab in the engineering department’s computer lab, as I want the students to follow me on a computer.

I was recently told that 75% of the incoming freshman at Dartmouth will be using Macs. All of this in spite of Macs significantly greater cost over a Windows based PC.

Since the students at our colleges and universities will be tomorrow’s leaders, this may portend big changes ahead in computing.

Folks,

The adventures of Patty and Rob continue.......

Rob bolted upright in bed. He had that terrible feeling that he had overslept for an important appointment. His eyes quickly found the clock and it said 10:30! 

“Wait a minute!” he thought, “It’s Sunday.”

He looked a Patty peacefully sleeping and decided to let her sleep. They had had a tough two months. Ever since they proposed increasing uptime to greater than 60% on two “experimental lines”, they were working 90 hour weeks. They just felt they needed to constantly monitor two lines, to assure that things were going smoothly. They felt satisfaction that they achieved 68.8% uptime in a two month period, compared to the company average 30.4%, which is still very good.

The local newspaper got word of this effort and did a story on Rob and Patty’s work. The article was well written and very complimentary to both he and Patty, as well as ACME. Sam Watkins, the site general manager, was very pleased with the good PR. The accompanying photos were really nice too.

The big shocker came this past Tuesday. “Sixty Minutes” called and said they wanted to do a segment on “The US Competing with the Far East in Electronics Manufacturing.” In agreeing to be interviewed, Rob and Patty insisted that members of their ACME team be included. In addition, they felt it was only fair to include the efforts of Rita from their stencil printer and reflow oven supplier and States, their colleague from the component placement company. And they couldn’t forget Eric, from ACME’s prime solder paste supplier. These three folks helped Rob and Patty and their team to develop the plan to achieve the 60+% uptime.

An even bigger shocker came when the Sixty Minutes crew told them that Andy Grove would be in the segment because of his recent article in Business Week, How America Can Create Jobs

 Grove insisted that to participate in the piece, he wanted to visit ACME to see what Rob and Patty were doing. So the Sixty Minutes crew was visiting ACME’s plant this week as were Rita, States, Eric and now “Andy.”

“Maybe we should call him Mr. Grove,” Rob thought.

Rob had suggested that he and Patty go to Berdick’s in nearby Walpole, NH for Sunday brunch and then to play golf. Rob had to chuckle, it was mid July and he and Patty had played golf 27 times (she kept a spreadsheet), he had beaten her 14 times and she was miffed. Even during their 90 hour weeks they would take a break 3 times a week to play 9 holes.

On Monday they were meeting with site GM, Sam Watkins, to discuss what they would tell Sixty Minutes.

Rob and Patty’s Sunday was delightful. The brunch was delicious and relaxing and they both played golf well, Patty’s 68 beating Rob’s 69.

It seemed like no time at all and Rob and Patty were in Sam’s office.

“Just assure me that this Sixty Minutes thing is not some expose that will embarrass ACME or put me in jail,” he teased.

Patty took the lead and explained what they had done. They trained the operators on the importance of line uptime, they worked with Rita, States, and Eric to develop a plan to assure that there would be minimum unscheduled downtime. They had to order extra spare parts and solder paste to assure no stoppages due to parts or paste shortages. One obvious thing is that they would be using two times or more the normal amount of solder paste. The two lines in the high uptime experiment had an average of one change over per day, consistent with ACME’s business.

They also increased routine maintenance on all machines. Both this maintenance and added spares was an increased cost, but these costs were second order effects compared to the dramatic profit increases due to almost 70% uptime.

Preparation for the next three jobs for each line was meticulous, so that setup time was minimized.  Feeder racks were used extensively in minimizing setup time for changeovers. In addition tape splicing was employed to minimize any assist time for component placement. States’ help was crucial in the component placement part of their efforts, Rob pointed out.

Patty went on to describe how Rita helped them in their efforts to develop minimum assist times for the stencil printing process.  The reflow oven presented the least concerns in assist or unscheduled downtime.

The solder paste they selected was robust in that it had a very good response to pause, excellent tack, and minimal slump.  The paste also had the best track record for minimizing defects like Head-in-Pillow and Graping.  Eric also participated as an enthusiastic partner in the effort.

Patty mentioned that their colleague, Phil, had agreed to monitor uptime for two standard lines during the two month trial to compare downtime metrics to the high uptime experiment. These would be experimental “controls.”

She then showed the uptime data for the two high uptime lines and Phil’s control lines. The control lines had ACME’s respectable 30% uptime, but the high uptime lines had almost 70% uptime. Rob went on to explain all of the things the team did to minimize downtime, most of it was common sense. Sam was especially interested in one downtime category.

“What is floundering time?" Sam asked.

 “That is time when the line is not operating due to some unplanned error,” Rob answered.

“Can you give an example?” asked Sam.

“Sure, you know how we have a quite organized approach to setups?” Rob responded.

“You mean our use of white boards to write down all of the things needed for the next 3 jobs on each line?” Sam came back.

“Yes, that is one of our biggest sources of floundering time,” Rob replied. He went on, “Someone will write that they have the stencil for the next job, when they just think they know where it is. When it comes time for that job the stencil cannot be found and an hour is lost.”

“Phil also noted a case where a job was finished on a line at 11:15AM, since lunch was at 12 noon, the changeover for the new job was not started until after lunch. Forty five minutes was lost, forever,” Patty added.

Sam gulped.

“So we are losing more than 25% uptime to ‘floundering?’” Sam weakly asked.

“According to the Professor, it’s endemic in the industry,” Patty interjected. “He coined the term, ‘Floundering time’,” she went on.

Sam then mentioned how the “bean counters” at ACME we really impressed with the two high uptime lines. ACME’s CEO wants a concerted effort to transition all of ACME’s assembly lines in North America  to higher uptime performance. Manufacturing in North America would also mean no 2-4 weeks of transportation time from the Far East. Patty, Rob, and their “team” were to form a new group in ACME to do this. Patty would be the Director of the group.

As the meeting was about to close, Sam asked what surprises Patty and Rob had during this experiment.

Rob then shared, “It relates to floundering time.   We found that even among the engineers, no one appreciated the value of one hour of production time. We asked a group of operators what an hour of production was worth and the figures ranged from $50 to $500 dollars. ACME runs two shifts at 30% uptime, that’s about 1500 hrs per year. Our typical line produces $30 million per year, that’s $20,000 per production hour. When we told the operators this, floundering time dropped significantly.”

Patty added, “The other thing we saw is that a “watchdog” is needed. If someone isn’t constantly watching things, floundering and assist times will go up. Since productivity is doubled with a high uptime line, the added cost of a watchdog is insignificant.”

Epilogue: The Sixty Minutes Segment was a great success. Patty was made Director of Corporate Productivity, but was also asked to manage Pete, who would take over her old group. No one seemed to worry that Patty was Rob’s boss, except maybe Rob!

Folks,

The adventures of Patty and Rob continue........

 “No way Rob. I can’t buy this one,” shouted Phil.

“I’m telling you I did all of the calculations. I know it can work,” Rob shot back.

“No way! You’ve been hanging around The Professor too long,” Phil continued.

“Guys, you’re not arguing again are you?” Patty said as she approached the lunch table.

“Your hubby’s gone crazy Patty, why don’t you trade him in for me?” Phil teased.

Why? Is he crazy? asked Patty.

“He thinks that, if we can get uptime high enough here in the USA, we can compete with assemblers in low wage countries. He’s gone too far this time,” answered Phil.

“Hear me out,” responded Rob. “Our uptime is about 30% on our lines. Patty and I made some measurements in China and uptime there is about the same. I did some calculations with ProfitPro and I’m convince that if we can get our uptime to greater than 60% we can compete, even if they pay only $0.75/hr vs our $12.50,” Rob finished.

Rob showed the ProfitPro output and sure enough the numbers didn’t lie.

Jan Curtis chimed in, “But Rob, that is theoretical. Realities might set in that will cause unforeseen problems.”

Phil agreed, “The only way to prove it is to do it.”

“You’re right,” said Patty, “Let’s do it!”

“Whoa girl! How can we do it?" asked Rob.

“Let’s develop a plan and go to Sam the GM and ask if we can do it,” was Patty’s answer.

All agreed it was a gutsy move, but worthy, and the only way to prove the point one way or the other.

So, Patty and Rob made an appointment with Sam Watkins, the site GM. They were admittedly a little nervous about the meeting. They both agreed that Rob should speak since it was his idea.

“To what do I owe the honor of a meeting with our recently married superstars?” Sam cheerfully greeted them at their meeting.

Rob explained their idea and showed Sam the ProfitPro output. He then requested that they be allowed to manage two assembly lines at ACME to show if increasing uptime to 60% was possible.

“So basically you are asking me for permission to improve our uptime on two lines to help us make a lot more money?” Sam asked. “Do you have a plan?” he continued.

Rob and Patty proceeded to show Sam their plan, and the two assembly lines on which they hoped to implement it.

Is it possible to pay US-type wages and compete with low wage countries? Will Patty and Rob be successful? Stay tuned for the results.

Folks,

Patty and Rob return from their honeymoon.......

Patty had just finished some emails and was ready to head off to meet Rob and some of their buddies for lunch. When she and Rob returned from China a month ago, Sam, the site GM, told both of them he was giving them an extra week of vacation for their honeymoon. Their China trip had been an unqualified success in helping the China teams achieve more productivity and higher yields. Sam had received numerous positive reports from the Chinese managers involved. There were several requests to have Patty and Rob stay a year in China to help with the many process issues that the China team has. Fat chance of that happening, Sam needed Patty and Rob here! Sam also mentioned that he knew that the trip was a little stressful coming so close to their wedding, so the extra week was ACME’s gift to the young couple for their sacrifices.

The wedding went off without a hitch. Patty was touched at how choked up her dad was in “giving her away.” The weeding reminded Rob and Patty how close they were to their parents. They both agreed that the support of their parents was crucial in any success that they had in life.

For their honeymoon they decided to tour France, Italy, and Germany. Rob was really proud that he handled the languages a little better than she did. Of all the things that they saw, they were most impressed with Pompeii. Because the city was covered in hot ash in a matter of moments, it was as if Pompeii was frozen in 70AD.  Visiting Pompeii was like stepping back into the time of the Caesars.

Truth be told, Patty was happy things were back to “normal.” It was pleasant to have their working schedule and to go home to their apartment at night. A couple nights a week, and most Saturdays and Sundays, she and Rob played golf. He had improved somewhat and she was a little annoyed that so far this year he had beaten her more than half of the time….and yes, he was rubbing it in.

As Patty approached the cafeteria she heard a friendly but heated discussion.

“No way can you evaluate an assembly company with just 10 questions,” Phil Anderson stated emphatically.

“I’m really convinced we can, I’ve thought it through a lot,” responded Rob.

“What’s the spirited debate about?" asked Patty as she sat down.

“Rob thinks you can evaluate an assembly company by asking a lead process engineer only 10 questions. Phil thinks he’s nuts,” responded Patty’s best friend Jan Curtis.

“I’ve thought about this quite a bit,” said Rob. “I’ve just finished reading Malcolm Gladwell’s ‘Blink.’”  “Gladwell claims that often the best judgments can be made quickly with just a sampling of data,” Rob went on.

“Be specific,” challenged Phil.

“OK, I actually developed 10 proposed questions to evaluate a assembler, let me list them and then defend them. Maybe you guys have better ones,” said Rob. 

Patty thought, as she heard this, that it was good news that ACME was looking to buy more assembly companies to handle their ever increasing workload……not like AJAX that was laying folks off.

Rob had come prepared, he actually had some print outs. His ten questions were:

1.      What is the composition of SAC305?

2.      What are tin whiskers?

3.      In a stencil aperture, what is the area ratio?

4.      What is an approximate peak temperature for a reflow oven in lead-free assembly?

5.      A board is inspected after wave soldering and one lead is not soldered to the board. The board is run through the wave solder machine again and has the same defect on the same lead. What is the most likely cause of the defect?

a.       The solder temperature is too low.

b.      The pad on the board is oxidized.

c.       The preheat temperature is too high.

6.       What are local fiducials on a PWB for?

7.       What does thixotropic mean in regard to solder pastes?

8.       A chip shooter places passives at a rate of 36,000 per hour. It is placing 300 passives on a PWB, how many seconds will the chipshooter take to place the passives on one board?

9.       A reflow oven belt speed is 100 cm/min. The PWB is 40 cm long. What is the minimum cycle time that the oven can support?

10.   What is tombstoning?

“You have got to be kidding,” shouted Phil, “everyone will score 100% on that test.”

Jan chimed in, “I’m not so sure. We hang around people all day who study this stuff. I’m not sure the typical process ‘engineers’ have enough time to study and learn new things…..Remember the 'water in the solder' and the 'isopropyl in solder paste' incidents?”

At this comment, Phil spit up his ice tea and started choking from laughter. One of their friends, Sally Herman, had been sent to a recently acquired company to help them with assembly process issues. One of the “process engineers” introduced himself by bragging that he was saving the company money by taking used, dried solder paste and mixing it with isopropyl alcohol so that the paste could be used again. Later in the day, the same chap shared that he thought he had a solution to the poor hole fill problem in lead-free wave soldering…….the solder was too thick, if it was mixed with water it would fill the holes better he opined.

Jan added, “As a minimum these questions act as a good screening process.”

Rob interjected, “That’s my point. I’m not saying this tells us everything, but you will agree that if a lead process engineer can’t handle these questions, it is unlikely he or she would be able to solve graping, or the head-in-pillow defect, right?"

All at the table murmured agreement.

“On second thought, maybe you have something here Rob," Phil said. “What do you propose as a passing score," he went on?

“Seventy percent,” Rob answered. 

Are Rob’s questions reasonable to evaluate an electronics assembler? What are the answers? Comment with your answers. Stay tuned to find out.

Cheers,

Dr. Ron

The image above is from: http://en.wikipedia.org/wiki/File:Blinkgla.jpg

Folks,

Tin Whiskers (TW) continue to generate considerable interest. People often suggest that their risk is great and yet unknowable. RPN may help to clarify the TW risk. What is RPN? It is the risk priority number from failure mode and effect analysis.  As this link tells us:

A failure modes and effects analysis (FMEA), is a procedure in product development and operations management for analysis of potential failure modes within a system for classification by the severity and likelihood of the failures. A successful FMEA activity helps a team to identify potential failure modes based on past experience with similar products or processes, enabling the team to design those failures out of the system with the minimum of effort and resource expenditure, thereby reducing development time and costs. It is widely used in manufacturing industries in various phases of the product life cycle and is now increasingly finding use in the service industry.

RPN is an important part of FMEA. It is the product of three numbers that range from 1 to 10. The first number is the severity (S) of a possible fail. A “10” would be given if the failure injured someone, “7” would be assigned if the failure caused a high degree of customer dissatisfaction, whereas a “2” would be given if the failure has only minor negative effects.

The second number is occurrence (O) of a fail. The highest rating is a “10,” which would be a failure every day (reminds me of Windows ME!) or one fail in 3 events, whereas a “7” would be a failure every month or one in 100 events. A “2” is a six sigma fail rate.

The last number is detection (D) of a potential fail. A”10” would suggest that the detection of a potential fail is either not performed or not possible. A “7” is a manual detection approach that may not be reliable, whereas a “2” is 100% effective potential failure inspection.

So obviously a product with a RPN of 10x10x10 = 1000 is a disaster, its failure is dangerous, frequent and incapable of being detected beforehand. Industry rules of thumb suggest that and RPN of 200 needs to be addressed and an RPN of 75 is usually considered acceptable.

Let’s look at a “ball park” RPN for tin whiskers (TW). We will assume the application is a critical IC in a PC.  Let’s assume that a severity rating of “S” of 8 (failure renders the unit unfit for use) is reasonable. TW are hard to inspect for future fails, so detection, “D,” could be as high as a 10. At this point we are at 8 times 10 equals 80 for both. A bad start.

Occurrence , “O” for TW failure modes is dramatically different. When trying to assess the occurrence of TW fails, one is often directed to NASA’s web page . Many reference this web site that lists a little more than a score of TW fails. What escapes me is that people don’t seem to appreciate the rarity of less than 100 fails in decades of data collection. Surely TW fails are not common. I could find no report of a failure of a RoHS compliant product anywhere on the internet. So it would be hard to rate “O” any higher than a “2.” I suspect that the reason few TW fails have apparently occurred is due to TW mitigation techniques that are widely practiced.

I would expect that “modern” process defects like the head-in-pillow or graping defects could have a much higher RPN than TW, if assembled without proper process controls and materials. However, there is little need to worry about these defects either, if you use the right solder paste and practice some assembly process precautions.

Patty, Rob, and The Professor finished their tasks in Shenzen and were flying to Shanghai for their last set of challenges in electronics assembly.  Then they would head back to the US, Rob and Patty being only a week away from their wedding day.

As usual Rob, conked out as soon as the plane lifted off. Surprisingly, The Professor also drifted off to sleep. Patty was too excited to sleep. Rob’s mother had given her and Rob their wedding presents early … an iPad  for each. They decided to bring only one laptop and one iPad. Patty was a little nervous about using the iPad for presentations but it worked quite well. She was still surprised that the iPad did not have a USB port. The Professor also gave each of them an early wedding present, a Pickett slide rule for Rob and a K&E slide rule for her. She must be the only person in the world right now that was watching a movie on an iPad and solving a math problem with a slide rule!

True to form, The Professor was passionate about how learning to use a slide rule helped improve a person's innate math ability. He showed Patty and Rob how to use them and gave them several assignments. Rob was better with his slide rule than Patty due to the amount of “one on one” time he had with The Professor. She had to admit that using the “slip stick” gave one more of a feel for calculations and it was consistent with one of The Professor’s adages: “Always know approximately what the answer to a calculation should be…..it will help you to avoid errors."

In addition to the iPad and slide rule, Patty was excited to be going to Shanghai at the time of the World Expo 2010. Our trio had scheduled some time at the expo into their busy schedule.

Their plan was for Rob and The Professor to work on some productivity issues and for Patty to take on some of the process materials related problems. The three of them again met with the site GM for ACME’s newly acquired plant in Shanghai, a Mr. Wong. Wong was relieved to find that they all spoke Mandarin, as his English was a little rough. When The Professor addressed him in excellent Shanghainese, everyone was speechless. Patty was determined to ask him about this later. No American spoke Mandarin, Cantonese, and Shanghainese!

They again agreed to stick to Mandarin. Patty headed out to the line, accompanied by a young Chinese engineer, Zhou Chang, who seemed to be taking more interest in her than expected. She tried to make her engagement ring visible, but she wasn’t sure the he knew of the significance of it. When she got to the line that was experiencing yield problems, the Engineering Manager, Fei Ding, met her. He showed her some of the fails and she quickly identified the head-in-pillow (HIP) defect as the likely culprit. After investigating some more fails, looking at stencil printing, some of the BGA components, and component placement, she asked Zhou Chang what spec was used to thermal profile the line.

“I don’t understand what you mean,” Zhou said in Mandarin.

“How do you determine what the reflow profile should be?”  Patty responded.

With more discussion, Patty determined that they had one profile for all products! Fortunately most of the products were of similar, small thermal mass.

“What solder paste do you use for this line?", Patty asked.

The embarrassed silence suggested that Zhou did not know! They grabbed a tube and Patty was relieved to see that it was one of her favor solder pastes. Since profiling was so rarely performed, Patty and Zhou had to go to another part of the complex almost a mile away to find a reflow profiling unit. After taking the profile, the likely solution appeared. The 11 zone oven was very long and the reflow profile had a long thermal  “soak” before the temperature went above liquidus. This long soak probably exhausted the flux, so that when the PWB went above liquidus, there was little flux left, resulting in oxidation and poor reflow.

All during their time together she had mentioned that her fiancé Rob was here, with her on the trip. This information seemed to do the trick.

“Zhou, why don’t you look up the solder paste spec on the web and then set up the right type reflow profile,” Patty suggested.

It was clear that Zhou was troubled. It became obvious to Patty that Zhou did not know how to profile a reflow oven. Patty set about working with Zhou to accomplish this mission. Within an hour they had re-profiled the oven and, over the next two hours, 300 PCBs were manufactured with the yield improved to 95%.

Patty asked Fei if she could give a brief presentation on the head-in-pillow defect to his team and he cheerfully agreed. Fortunately for Patty, her friend Mario Scalzo had given her his presentation that he gave at APEX 2010 on HIP (head-in-pillow). Patty always enjoyed visiting Mario in Utica, NY, as he always knew the best restaurants in town.

Her major points were:

HIP is caused by the failure of the BGA sphere to reflow with the solder paste. There are 3 major reasons for HIP:

1.       Supplier Issues

a.       Solder BGA sphere oxidation

b.      Silver segregation to the BGA sphere surface

2.       Process Issues

a.       Stencil Printing

                                                               i.      Registration accuracy

                                                             ii.      Insufficient solder paste

b.      Component Placement

                                                               i.      Off pad

                                                             ii.      Out of plane

                                                            iii.      Non optimum pressure

c.       Reflow

                                                               i.      Inappropriate reflow profile

                                                             ii.      Flux exhaustion

                                                            iii.      PWB warpage

3.       Material Issues

a.       Poor solder paste transfer efficiency

b.      Insufficient solder flux oxidation barrier

c.      Solder paste slump

d.      PWB or BGA warpage

Patty went on to say that she had investigated all of these issues with Zhou, and that the reflow profile was not optimum as the very long soak time had exhausted the flux. The other possible issues in the list did not seem to be a concern.

At the end of the day Patty, Rob, and The Professor met at the GM’s office to leave together for dinner and the Expo. Patty had to ask, “Professor, how can you possible know Mandarin, Cantonese, and Shanghainese?”

“Actually I speak Min reasonably well too,” he replied.

“How can this be?", Rob inquired.

“Mother and father were missionaries with Wycliffe Bible Translators,” The Professor answered.

“I grew about around many languages during my youth. Mother and father speak more than I do,” he finished.

Patty went on to tell about the interest that Zhou Chang seemed to have in her, and how she had to discourage him.

“The burdens of being a beautiful young woman,” Rob teased.

Patty elbowed him, but they all left the taxi laughing as they headed for a restaurant near the Expo.

Best Wishes,

Dr. Ron 

The Shanghai, slide rule, and HIP images are from: 

http://pool14.files.wordpress.com/2008/12/shanghai_skyline_g.jpg

http://www.hpmuseum.org/powerlog.jpg

http://ppsimanufacturing.files.wordpress.com/2010/03/bga100.gif

Folks,

After a bit of a break, the adventures of Patty, Rob, and The Professor continue:

The plane droned on as it made its slow march from Detroit to Tokyo.   Patty looked down at Rob as he slumbered peacefully. She caught a glimpse of The Professor,  he looked at both of them from across the aisle with a satisfied smile. The proud mentor looking at his mentees. 

This was the first time in a while when Patty didn’t feel totally stressed. She had resisted going to China only three weeks before her wedding, but senior management insisted. She would arrive home only 5 days before the big day. She and Rob had their first real fight, she got angry with him because he wasn’t appreciating the pressure that she felt. However, with one long weekend with their moms, she was able to get most of the tasks done and finally felt relaxed that the wedding plans were in good shape.

She had to chuckle at Rob. He was all nervous being with The Professor by himself. The plans that they had made had Rob and The Professor focusing on productivity improvements at ACME’s new acquired plants in China. While they were working on these tasks, Patty would handle some process materials related issues. 

The rest on the trip went smoothly and after a night’s rest they were off to the first of ACME’s new factories. This one was located in Shenzhen. Our trio was ushered in to see the site GM, Peng Zhou, a native of the area. He addressed them in quite good English. When Rob and Patty answered in better Mandarin, he seemed shocked. When The Professor answered him in flawless Cantonese he and Patty and Rob were stunned. 

"要不咱们都讲中文吧，既然咱们中文都不错。" said Rob. ("Perhaps we should all speak in Mandarin, since we speak it well." For our non Mandarin speakers)

Rob and The Professor went off to audit a few assembly lines, while Peng accompanied Patty to visit an assembly line that was having a quality problem.

(Dialogue translated from Mandarin)

“I’m very impressed with how well you all speak Mandarin,” said Peng. “Where did you learn it?” he continued.

“Thank you,” replied Patty. "Both Rob and I studied Mandarin in college and we did an internship in China,” she went on.

“ Very impressive,” Peng commented. “But I have to tell you, I’ve never heard any American speak Cantonese at all, let alone as well as The Professor does. It’s like he was born here,” he went on.

“He never ceases to amaze me,” Patty responded.

Patty and Peng finally arrived at the assembly line. Patty was introduced to the line engineer, Elvis Chang. She chuckled inside, this was the third Asian person her age she had met that had chosen “Elvis” as an English nickname. Elvis was relieved that Patty spoke Mandarin. They went to a stereo microscope and looked at some of the assembled PCBs that had quality issues. Patty was quick to pick out the problem:  graping. She looked at the stencil and the pad sizes on the PCB. She performed a few calculations and appeared satisfied that she had the answer. Patty suggested that, if Elvis would like, she could give a brief presentation on what she thought the problem was.

“Patty, that’s a great idea, but it might be best to wait until after lunch,” Elvis suggested.

Elvis, Patty, and a few other young engineers went together for lunch. They seemed to be fascinated with Patty, especially her ability to speak Mandarin. They all spoke some English and were all studying it as they recognized that their ability to be promoted to a senior level required fluency in English. One of them pointed out that she had read that about 250 million Chinese people are studying English, while only 20,000 Americans are studying Chinese.

Patty enjoyed Chinese food and was happy to find Sea Cucumber on the menu. One of her friends said it was the only Chinese food he couldn’t eat. She tried it and liked it.

After lunch, Patty asked for a few hours to prepare her presentation. Her main points are summarized below:

1.        The aperture size for the pads that experience graping is 8 mils in diameter for the 4 mil thick stencil.

2.       The resulting area ratio (D/4t, D= diameter, t = stencil thickness) for this aperture is 0.50, less than the recommended 0.66.

3.       The very small solder paste deposit doesn’t not have enough flux to avoid oxidation of the solder particles in reflow. The resulting defect looks like a bunch of grapes so it is called graping.

4.       Likely solutions:

a.       Use a square aperture. An 8 mil square aperture provides 27.3% more volume, and it has better transfer efficiency. (Transfer efficiency is the volume of the solder paste deposit divided by the volume of the aperture times 100.) The result would be > 30% more solder paste. The more solder paste, the less likely to experience graping

b.      The solder paste they were using was not best of breed re: graping resistance. She recommended another one, which she knew performed well in all respects - and minimized graping. This solder paste’s flux was robust and designed to minimize defects like graping.

Her presentation was received very well. Fortunately some of this excellent solder paste she recommended was being used for another job in the plant. So with approval from Peng, the team switched to this paste.

After the meeting, Patty thought about how much one of the technical engineers from one of her favorite solder paste suppliers had helped her to understand graping and how to minimize it. His name is Ed Briggs and she had just attended SMTA Toronto where Ed gave a paper on graping. Much of the information in her presentation came from Ed’s paper. She had also learned from one of his blog posts on graping.

Epilogue: Three weeks later, the graping had disappeared from Elvis’s assembly line. They didn’t even need to adopt a stencil with square apertures, the solder paste change, itself, was enough.

Cheers,

Dr. Ron

Folks,

I think the analysis is a little off in a recent posting by Dominique Numakura Re the cost of a product like the iPad. Numakura states:

Consumer electronics product manufacturing cost must be less than 33% of retail price. Total component cost must be less than 25% of product retail price.

In a tear down analysis, performed for Dartmouth by my colleague Jim Hall of ITM, Jim used cost metrics similar to Numakura’s, for a hairdryer. The hairdryer cost $20 at a CVS drugstore.  The same model is manufactured overseas for CVS and other stores, like Walgreen’s, with perhaps a different label.  After manufacture, the hairdryer is shipped to a distributor. From the distributor, it was then shipped to the drugstore. So assuming that the manufacturer has to make it for 33% of $20, or about $6.70, the distributor needs to get $3 dollars or so, shipping several times adds another few dollars and it gets to the drug store for $13-$16 or so. Many hands have touched it by now, all adding cost.

For something more expensive and complex like the iPad or a laptop, this analysis is considerably off. There is no distributor, the number of hands touching these devices is minimized by the parent company. Less shipping is involved. I’m sure folks that make these products wish the margins were like Numakura suggests. The recent analysis performed by iSupply, which I think Numakura takes issue with, is closer to the mark, I think. iSupply suggests that the BOM (bill of material) for the entry level iPad ($499 retail) is about $250 or 50% of the sales price. I actually think iSupply’s estimate of the assembly cost ($9.00) is too low. In the past, Prismark had suggested that assembly and test is in the 10-15% range of total price, indicating something like $50 for our iPad. From another assembly cost perspective, a rule of thumb is that it costs between $0.05-$0.10 per component to assemble and test an electronic device. It is hard to imagine that the iPad has only 200 total components (including passives!), that a $9 assembly cost would require. Hence, I think the assembly cost would be more than $25. If so, this suggests a total cost of about $275 for the $499 iPad, still leaving a quite healthy gross margin of 45%. Commodity type electronics in the multiple hundred dollar range (e.g. a “vanilla” laptop or a 32” Flat panel TV), almost certainly don’t enjoy these levels of gross margins, probably more like 10 to 20%.

While preparing to write this post, I shopped at a BJs. I saw a 32 inch flat panel TV for $379. It is hard to image that the BOM for this TV would be $95 as Numakura suggests.

Cheers,

Dr. Ron

Folks,

APEX 2010 appeared to be a great success. Attendance was high and my “Lead-Free Assembly” workshop broke a personal record of about 60 attendees.

While at the show, I was invited to a meeting on solderless assembly, ably organized by Phil Marcoux. About 15 people were at the meeting. The intent of the meeting, was to crystallize what is needed to make solderless technology a reality. Many have suggested that solderless assembly’s time is now. The main reason being the challenges of lead-free solder-based assembly and its perceived lack of reliability. Some believe that solderless technology is a next logical step in assembly on the order of importance of the advent of SMT assembly.

I was well behaved at the meeting (I am a somewhat renowned skeptic of solderless assembly), but pointed out, early on, that any solderless assembly technique (the Occam process being a likely contender), must be disassemble-able to meet the requirements of WEEE.

Much spirited but pleasant discussion transpired, related to what is needed to make this technology a reality. Several folks mentioned that a “killer app” would be needed to kick-start solderless assembly, and supply the considerable monies needed.

Finally, near the end of the meeting, Phil, suggesting I had been too quiet, and asked me to chime in. I said that I agreed that a killer app was needed, and proceeded to tell a story. It went as such:

Let’s say it was several years ago and Steve Jobs heard about solderless technology.  He was wondering if it might be right for Apple’s future killer app, the iPad.  So we are invited to visit him on Infinity Drive. After confidentially agreements are signed, he starts speaking.  He proceeds to tell us that the BOM for the entry level iPad is $250 and assembly adds $9 .  Reliability of lead-free products has been equal to, or better than, leaded products and lead-free enables finer PWB lead spacings than does leaded solder.  So he is not unhappy with lead-free assembly, but would like to do solderless technology, if it makes sense.   The assembled cost has to be less than the $259 and solderless reliability must be better.  We would need to be ready for an April 2010 launch. 

I think the cost metrics in this scenario would be difficult for a solderless technology to compete with. And, even if the price was a few dollars less, what is the compelling reason to change?

SMT arrived because through-hole technology could not meet the miniaturization requirements of modern electronics. We could not have modern electronics without SMT. What are the compelling reasons solderless technology should be used in an application like the one discussed above? The answer still escapes me.

Cheers,
Dr. Ron

Image source.

Folks,

 Bob Landman’s comments to my tin whisker posts appear below. Friendly dialogue such as this helps us to all learn more and is appreciated. Thank you Bob, keep me honest!

However, Bob’s comments do not change my position, which is:

1.     Tin whiskers exist and can cause failures

2.     However, there is yet no data that suggest that there are numerous tin whisker failures, or that a significant reliability risk exists due to tin whiskers in RoHS-compliant products.  NASA's TW website notes only 26 fails.

3.     Although not completely understood, tin whiskers can be created in the lab, and mitigation (not elimination) and reliability test techniques exist and have been demonstrated.

4.    With well over $1 trillion in RoHS-compliant electronics manufactured since the early 2000s, there have been no significant reliability issues as compared to tin-lead solder.

5.     Long term lead-free reliability (> 5yrs) has not been demonstrated. Hence, mission critical products should not use lead-free electronics at this time.

6.     Tin-lead solder does not assure defect-free electronics with perfect reliability.

As I type this post, I am surrounded by more than 20 RoHS-compliant products, some dating from 2005. Outside my office, at Dartmouth’s Thayer School of Engineering, is our computer center. The thousands of RoHS-compliant products that the computer center buys each year (they get me my laptop, etc)  are almost all RoHS-compliant. No unusual reliability issues have been noted.

Bob mentions that CALCE reports that 31% of laptops fail in 3 years. This number actually seems low to me. Upon reading the paper, one finds that over 10% of the 31% is due to accidents. 
A study of 100,000 hard drives at Google suggests that hard drive fails are in the 5% range per year, which may account for much of the 20% of fails in 3 years. But what solid conclusion can be made from these data? Nothing, unless failure analysis is performed.

The sky is not falling. Lead-free has process-ability and reliability challenges, such as graping, head-in-pillow, voiding, etc. With data-driven process optimization at all steps in the manufacturing of the ICs, components and assemblies, good lead-free yield and reliability can be achieved.

Lead-free is here to stay. It is up to us to perform the experiments and develop the techniques to assure that RoHS compliant products have acceptable reliability.

Bob's comments follow:

My source for the dead vehicles that arrive at car dealers having whisker problems, comes from my former professor of physics, Dr. Henning Leidecker at NASA Goddard Space Flight Center in Greenbelt MD.   Dr. Leidecker said that in the last four years his office has been contacted by seven major suppliers of automotive electronics inquiring about failures in their products caused by tin whiskers. He said his office has contacted Toyota offering to help analyze its acceleration problem, but hasn't heard back. For full context, read the rest of the article [http://wtop.com/?nid=108&sid=1898265].

Ron Lasky confirms that parts plated in pure tin will grow tin whiskers "with a certain amount of aging". According to NASA, whiskers can grow in hours, days, weeks, months or years. It depends on at least six factors; the quality of the tin plating, the residual stress in the coating, was the coating annealed or not, grain uniformity, temperature, humidity, and unknown other factors we don’t yet understand which is what makes it so difficult to stop whiskers from growing and is why there are so many papers published on the subject (as you can clearly see at John Barnes website) yet we still do not understand why or how they grow.

So yes, is entirely within the realm of possibility that "new" products have failed due to tin whiskers or perhaps dendritic growth.

NASA cannot tell us who the manufacturers are who reported these events due to confidentiality agreements.  Dr. Leidecker says they get these calls from other industries as well and most request a non-disclosure agreement.  NASA feels it’s better to get some information rather than none, don't you agree?

Last  week at CALCE at UMd. it was reported that 31% of all laptops fail within 3 years. This is the link to the report http://www.squaretrade.com/pages/laptop-reliability-1109/  No information is given as to what has failed. Is it due to whiskers?  We do not know.

What we do know is that the laws of physics have not been repealed.  Tin will most certainly grow whiskers so using leadfree solder and tin plated components has to result in tin whiskers growing.

NASA continues to log failures.  NASA Goddard is now studying the Toyota incidents for NHTSA.  Again, a non-disclosure statement has been signed so they cannot comment on the study at this time.

Dr. David Gilbert of Southern Indiana University has demonstrated that a low resistance or shorted input between the wires from the pedal electronics to the electronics control module will cause Toyotas to open their throttles full.  Perhaps the problem is due to leadfree manufacturing (which Toyota admits it began in 2002-3)?  Perhaps it is software?  We don't yet know but we can be reasonably certain that not all the accidents are caused by the owners of the vehicles.  You can see pictures of the Toyota parts at my website [www.hlinstruments.com//RoHS_articles/Toyota/]   The pedal has a pc board layout that I would have been comfortable with.  In particular, the SOIC part that converts the signals from the Hall effect sensors (that sense pedal position) into 1-5Vdc signals sent to the electronic control module is very close to the edge of the board.  The board has serrated edges which indicates it was snapped out of a large panel of these boards after the parts were soldered to it.  It's possible a trace or lead has fractured or one of the capacitors or resistors.  We know that leadfree solder is more brittle than tin-lead. Perhaps a few boards are marginal and over time a lead opens or becomes intermittent?

The EU was warned that tin whiskers and brittle joints would result if lead was banned from electronic assemblies but went ahead and banned lead from tin-lead solder and platings on parts. They acknowledged the possibility of reduced reliability under intense pressure from hi reliability industries and did exempt some products (military, aerospace, etc...).  What difference did it make since the majority of component manufacturers refused to continue to offer tin-lead plated leads?  That is why NASA replates it's components with tin-lead at Corfin Industries and uses only tin-lead solder.


Bob Landman

http://www.hlinstruments.com//RoHS_articles/Toyota/Toyota%20Dr%20Gilbert%20Preliminary_Report022110.pdf

Folks,

After my recent post on the fact that there was no data linking tin whiskers to the Toyota sudden acceleration issues, there continue to be more posts saying things like “Tin Whiskers Implicated in Unintended Acceleration Problems.”  Many of these posts link back to the earlier TechEye post.   The basis for all of the posts, is a paper written by EurIng Keith Armstrong .   Armstrong’s paper is titled: “Toyota ‘sticking pedals’ recall is a smokescreen, Their sudden unintended acceleration problem is caused by electronics either due to EMI, lead-free soldering or software ‘bugs.’” It does not appear that Armstrong’s paper was sponsored or refereed. 

Since it appears that this entire wave of reporting implicating tin whiskers, in this important issue, emanates from Armstrong's paper, it is helpful to quote his entire comments on Tin Whiskers:

            "9.0 Lead-free soldering:

In recent years, various countries and trade blocs (including the European Union) have banned the use of lead on electrical solder, on the basis that lead going into landfill when electrical and electronic products are disposed of is bad for the environment, and hence for people.

But many accuse them of being shortsighted – lead has been added to solder in quite large amounts for many decades because it made the other main constituent, tin, behave much better, considerably improving reliability.

Now that lead has been removed from solder, which is now mainly tin (with a little silver and copper added) all sorts of new possibilities arise for short-circuits and open-circuits, and intermittent shorts and opens, mainly on printed circuit boards (PCBs) and mainly associated with small-footprint integrated circuits (ICs), especially ball-grid arrays (BGAs).

Its really just another cause of intermittent or fixed short-or-open circuits in electronic PCBs and modules - but one that would not have been any problem until a few years ago, and so could have caught Toyota by surprise.

John R Barnes has created a monumentally huge library of references to the problems of lead-free soldering, especially tin whiskering, see www.dbicorporation.com/rohsbib.htm. Prepare to be totally overwhelmed!

Removing lead from solder has the following effects:

9.1 Tin whiskers

These will grow out of soldered joints and can contact other conductors, causing short-circuits between PCB copper traces and the pins of connectors. They are often no longer than 0.5mm (about 1/50th of an inch) but can grow to 1mm (about 1/24th of an inch) or longer, especially in damp conditions.

Even at 1/50th of an inch they can short between the pins on a modern integrated circuit (IC). And the process of removing the PCB for inspection can brush them off, so you never find them.

And if you didn't accidentally brush them off, they are so thin they are very hard to see - you need a powerful microscope. They are as fine as the finest spider-web threads, yet can carry sufficient current to short-out the electronics. You won’t see them unless you are looking for them.

Being so thin, they can wave around in the breeze and/or due to shocks, vibration and acceleration, causing intermittent short-circuits.

The iNEMI organisation has published guidelines (www.inemi.org) on how to ensure that tin whiskers don’t grow too long, but I don’t know to what extent these are followed by suppliers of electronics to the car industry in general, or Toyota in particular."

Note that, in this paper,  there is no data or any evidence re: tin whiskers discussed from investigating any of the vehicles in question. All of this paper is an opinion.   In addition, the title of Armstrong’s paper leaves no room for any other cause, it has to be electronics or software. This position is very strong indeed for having no supporting data.

More recently Bob Landman added these comments to the tin whisker discussion:

“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 regard to the Toyota recalls] was, but I have heard recently of new autos showing up at dealers that will not start. That cause has been linked to tin whiskers.”

Bob heard this. There is no report and no data. Until Bob gives us a reference for some analysis and data, his comments are little more than hearsay.  I searched the web in vain to find information related to Bob’s quote. In addition this comment is a little surprising, tin whiskers are usually associated with a certain amount of aging, hence not usually found in new products.   

That tin whiskers exist and cause failures is irrefutable. NASA  has an excellent website related to tin whiskers and failures caused by them. However, the total number of tin whisker fails reported is less than 100. Many other types of electronic failure modes would appear to be much more common.

My purpose of writing this post is not to suggest that tin whiskers are not a concern in lead-free electronics. However, it is a fundamental principle in engineering and science to only make pronouncements on how something failed, when they can be supported with data. No data supports implicating tin whiskers in the Toyota incidents. It is also troubling how readily many people referenced the work of Armstrong without apparently reading what he said and checking his sources and lack of data.

Folks,

A reader commented that he liked the Patty and The Professor stories for their technical content, but he felt there was “too much story.”   So, I feel an explanation for why I think the “story” part is important.

Manufacturing is accomplished by integrating people, processes, equipment, materials, components and so forth.  Most of our discussion on improving electronic assembly in blogs and other media, focuses on materials, equipment, processes, BGAs, QFPs, lead finishes, PWBs, etc. Look back at the first sentence and compare it to the second sentence. The thing we seldom discuss in examining ways to improve quality and productivity in our electronic assembly processes are the foibles and strengths of people.

Let’s explore the people aspect of electronics assembly by way of two examples, ACME and AJAX. ACME has the best equipment, the processes have been optimized by designed experiments to produce outstanding quality, and they use the best materials. AJAX has similar things going for it. However, at the end of the year, AJAX has noticeably greater productivity and profit. 

What is the difference? People.

At AJAX, the workers have an understanding of the importance of productivity and a passion for their role in it. As a result, a stencil is seldom misplaced and a component placement machine is almost never without components in the feeders. In the long run, this type of attention adds up to 10% or so greater productivity and perhaps 20% greater profit.

This is why when Patty, Pete, The Professor, and now Rob, are out on an adventure, they clearly focus on the technical issues, but never fail to catch the people issues, too.

And so it is with all of us, people are our greatest resource.

Cheers,

Dr. Ron

Patty was checking her email. She noticed a note from someone who had attended last night’s SMTA meeting. Patty had just been elected chapter president, after giving a talk on the head-in-pillow defect. In her talk, she also shared how important it was to work closely with your materials and equipment suppliers. To her, it was obvious that her suppliers were interested in her success. If they were competent, why shouldn’t she rely on them for technical information and help. If she didn’t think they were competent, she should get new suppliers. She was surprised at how much “push back” she got from the attendees. Several people stated that they felt that suppliers where just out to make a sale and that a smart person just bought from the supplier with the cheapest price. Patty thought that this perspective was negative and self destructive. She was sure that 60% of all process knowledge was learned from her suppliers, either in person or at the technical shows like APEX and SMTAI. She felt the main reason to go to these shows was the technical program. And some of the best papers were presented by the better equipment and materials suppliers. 

One of their marketing VPs even told her, “We believe that the more technical help we give our customers, the more successful we will be.” 

“Well wasn’t that a condensation of what good business should be like?  He who helps his customer is the most successful,” she thought.

As she was thinking these thoughts a new email popped up on her PC. It was from Hal Lindsay, a noted curmudgeon.   Patty read on….

“ I heard you telling some of the people at the meeting last night that lead-free assembly had some process advantages: Hogwash. Lead-free has no process advantages, and it’s not needed,” he started.

After a few more complaints, he finished, “ It’s because of young tree huggers like you that never stood up and fought lead-free that we are in this mess to begin with.”

In preparing her response, Patty’s mind went back to some conversations about this she had had with The Professor. He had made two strong points:

1.       The first purpose of RoHS is to make recycling safer. So much recycling isperformed in poorer countries with chemically unsafe processes. RoHS compliant products will save the lives of the unfortunate people who have to perform this type of recycling to survive. 

2.       Lead-free soldering is challenging because the solder does not wet as well. This situation forced us to develop assembly processes with tighter process windows. However, an initially unseen benefit is that tighter lead spacings are possible with lead-free soldering because of this poore wetting. Many portable products such as mobile phones, could not be assembled with leaded solder. There would be too many shorts.

Patty was including this information in her response to grumpy Mr. Lindsay, when the phone rang. It was Rob.

He began, "我可能要出差去中国探访几家ACME在那里的新工厂。我想你可能也要在焊接工艺上做一些工作。"

(For our few readers that can’t read Mandarin: "It looks like I will be traveling to China to visit some of ACME's new factories there.   I think you will be going to work on some soldering issues too.")

“Whoa!,” Patty exclaimed, “Why would you be going to visit ACME’s factories in China?”

Rob went on, “You know things haven’t been going well here at AJAX, we never adopted “Lean Sigma” techniques like ACME did. Today, we had a layoff and I got hit.”

“Yikes!” screamed Patty. Her mind went through many scenarios with Rob being unemployed 5 weeks before their wedding.

“Easy girl,” Rob implored. “My GM called me in and said that he was sorry to see me go, but being a friend with your GM, he got me a job at ACME.   I am to be the liaison for the 3 factories that ACME has in China. My fleuncy in Mandarin made the difference,” he finished.

Patty and Rob were unusual for Americans, in that they both spoke Spanish and Mandarin. Both of their dads had encouraged them to take Mandarin at Tech as they had both taken many years of Spanish in high school. Both did a language study abroad (LSA) term and an internship in China. As their dads said, “If you can speak English, Spanish, and Mandarin, you can speak to almost any professional in the world.” Both Patty and Rob found that their language skills gave them a ready bond when they were abroad. One German colleague even told Patty that she was the only American he knew that would not fit the European view of Americans when they ask, “Are you bilingual, trilingual, or American?”

After Patty calmed down, she asked Rob why he thought she would be going.

He responded, “When your GM gave me the job offer on the phone, he alluded to a team visit to China, by me and this genius young woman that is a process expert. Apparently, they have some Head-in-Pillow, graping and productivity issues. I will be handling the business aspects, you the technical. He also mentioned he would like The Professor to go. I don’t think he knows we are engaged.”

Patty congratulated Rob and finished to conversation. She hoped that their being married wouldn’t create any issues in working together. She also was a little annoyed that she always seemed to be the last to know about trips that the executives were planning for her and her team. It was especially annoying that Pete seemed always know before her when they would need to go on one of their adventures. After all she was Pete’s boss. Well at least this time it was Rob, not Pete. There is now way Pete could know about this potential adventure.

She went back to finishing her note to cranky Hal Lindsay when she heard, “Pack your bags kiddo, it looks like China this time. Oh and Rob is going.”

 

Cheers,

Dr. Ron

I saw Patty at a recent SMTA meeting.  I mentioned that many of her fans would like to see a photo of her.  Surprisingly, neither of us had a camera.  As you remember she is also a self taught artist,  I asked if she would mind sketching herself.   Here tis.

 The reflow image of leaded and lead-free solder coutesy of Motorola.

UPDATE:

To be fair and thorough myself, I want to point out two things:

 1.       Several media, not just Circuitnet,  picked up the original story regarding tin whiskers as a possible cause of Toyota’s problems. The original article appears here: http://www.techeye.net/chips/electronic-tin-whiskers-may-be-behind-toyota-recalls

2.       Temporarily ignoring the poor science at the root of the “claim”, I maintain that editing out the key phrase “may be” from the original story contributes to an increased misunderstanding of the actual facts.

Now, here is my original post:

Folks,

Every so often a new electronics assembly technology comes along, and I am asked my opinion about it. The latest “new” technology for assembly is RF Activated “Green” Nano Solder.

My response when asked about this follows:

“I think Intel's caveat in the article tells it all:
 
‘Intel cautioned, however, that several engineering refinements need to be made before the new RF soldering method can be used commercially.’

 
Interpretation: This puppy needs $20 million of R&D before it is ready.
 
Nano solders have been studied for years.  They are interesting and have promise, but there are big hurdles.
 
People will say they want an exciting new technology like this, until that find that the soldering material costs much more than their current one, they need new equipment, etc.  All of the sudden today's process (disappointments included) doesn't look so bad.  It is hard to replace an incumbent process unless there is a strong need - and typically it must be at equal or lower cost.  These will be challenges for this proposed process.
 
So my take is, it is interesting process science, but let's wait awhile to see more data, prototypes and cost estimates before we get too excited.

Any new technology process must be evaluated under the following criteria:

1.     If “disruptive”, it must meet an overwhelming need. E.g.: If your process has a 95% first pass yield and the 5% of the product that is repaired only cost a small amount, you will be unlikely to want to take a chance on a new, unproven technology when the time comes to invest money in it.

2.     The new technology’s implementation must have a minimum of disruption, if implemented in a current process and the cost must be equal or less than today’s process. E.g.: You want to improve your process in #1, however if the new process requires radically new equipment and/or materials you will be hesitant to adopt it.

3.     The process will need several years to prove itself. You know the problems with today’s process, but what are the problems with the new process? You will likely want yield and reliability data. These requirements will take some time.

4.     You must consider the improvements in the old process. Often a new process will aim at where the old process is today, not recognizing that the old process is often improving by the time the new process is implemented.

Using these criteria, let’s look at the implementation of SMT technology in the age of through-hole (TH), circa 1980. How did it measure up to these four criteria?:

1.     SMT met an overwhelming need. One simply could not design a small, high performance personal product, like a mobile phone, with TH.

2.     SMT lines evolved from TH lines, sometimes with radical changes, but the need overwhelmed any disruption.

3.     Much work was performed on SMT products to demonstrate that reliability was acceptable.

4.     The need for SMT was so great that TH's "future" was not an issue.

Contrast this situation to the SMT process discussed above (that has 95% first pass yield) with the 5% fallout reworkable. It becomes difficult to envision making any “disruptive” change to a process like this…..it just won’t pay financially or in any other way.

Your comments?

Dr. Ron

Patty, Pete, and John prepare to do battle with "The Big O."

Patty and Pete were able to squeeze in 9 holes of golf, though it was really 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 9^th 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 stumbled out.

“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 attributed 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 re-instate the use of nitrogen in the wave soldering process. First pass yields have dropped from 94% to 87%, thus increasing re-work. 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 gesticulated 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 Dinardos at 7PM? Bring John with you.”

Patty was glad that she backed up her files last night on SugarSynch, even though it looked like her laptop was fine. 

Colonial Williamsburg was only a 45 minute drive away, and it was just 10AM. 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 restuarant, 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 very 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.

These 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 out of 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

Folks,

Our trio continue on their adventure:

As Patty, The Professor, and Pete maneuvered around the partially completed product, Patty noticed signs everywhere that proclaimed: “Being Responsive to Our Customer is Our Biggest Asset.” 

Pete commented, “This place is so crowded with partially built product that not another tube of solder paste or even a solder perform could fit out here.”

Our trio then approached a technician who was working on a product changeover. Patty introduced herself in Spanish and asked what he was doing.

Pedro’s face beamed when he heard Patty addressing him in his native tongue. He responded to her in Spanish (translated here.)

“I’m doing a product changeover,” Pedro replied, “We are really good at them, because we do so many. This is actually the second changeover I’ve done on this line today,” he continued.

“Your first job, must have been a very small lot size,” Pete commented.

“Oh, no,” Pedro chuckled. “We never ran the first job.” He went on, “Another more important job than the fist came along and we were told by our supervisor to changeover for that one,” he added.

“You mean you never ran any boards for the first job?", The Professor queried.

“That’s right,” said Pedro. “This only happens a couple of times a month,” Pedro confirmed.

“I really like working here,” Pedro shared. “I feel proud that I have learned to be so good at change-overs and all of us have been able to work a lot of overtime since the ‘Being Responsive’ campaign started. We feel like we are really making a difference and getting great pay,” he beamed. “Just look at all of the product on the floor,” We are really producing a lot of stuff,” Pedro boasted.

Our team strolled away from Pedro and his co-workers and ran into a very hyper man, Phil Marcos, production manager. Phil was one of those types that made you nervous just being near him.

“Great job! Great job!, These folks are really supporting my responsiveness campaign,” Phil projected at 250 words a minute in a strong Long Island accent. “I don’t have much time to chat, I have to stop production on line 4 for a 'Being Responsive' job that just came in. I need to have Pedro and the ‘changeover guys’ change that line over for this new job,” he finished as he trotted away. “He looked back and said, “I’m so excited that next quarter we will have 15% more production and that sales are up 10% this year.”

As Phil left, The Professor commented, “It’s a good thing Phil doesn’t speak Spanish, I’m not sure my ancient brain could process 250 Spanish words a minute.” 

They all burst out in laughter.

“I wonder where they will put all of the WIP when production increases 15%?” asked Pete.

Our team spent the better part of two days reviewing production and inventory figures. They learned that the site had 8 SMT/Through-hole mixed assembly lines. Before Phil Marcos arrival, normally six of the lines were dedicated to jobs with very large lot sizes. Some of the jobs ran for months without a changeover. Since Phil’s arrival, more high mix, low volume jobs have been sought after by sales. The two lines, devoted to such jobs in the past, were not enough to handle the new high mix jobs. The customers demanded fast turn around for these jobs as they paid a 5% premium. Since profit margins at this site were about 10%, these jobs seemed like a great deal financially. The meet this new demand most lines were regularly disrupted. There seemed to be little logic in how a line was selected, but all agreed that the facility looked “responsive.”

Pete found a room for Patty, The Professor, and himself to review the data. Pete had been watching The Professor and it was clear that he was holding back to let Pete and Patty learn by searching for the answer without too much help from him.

“The loss in profit clearly relates to the changeovers,” Patty said. “Professor, why don’t you let Pete and I figure this one out and see if we get it right?” she added.

The Professor beamed at his two protégés.

After numerous calculations, Patty and Pete presented their conclusions to The Professor. After a few minor suggestions, The Professor agreed with their conclusions. They went off to review their findings with Harry Hopkins, Jane (the new corporate CFO), and hyper Phil Marcos.

Patty started the meeting with a preamble.  “We developed a spreadsheet of costs, sales and profit. We are sure it is not the type of format finance uses, but it helps us to understand the problem,” she began. 

She projected the spreadsheet onto the screen and continued, “As you can see, sales are indeed up by 10% for this year, but that extra income was more than lost because inventory costs are up 66% and labor costs up 22%.” Patty went on, “The labor cost is understandable, you are doing many changeovers, often on second shift. Not only do you have to pay overtime premiums, but the many changeovers cause some disruption to all workers…..your breakrooms have never been so crowded!”

“Inventory carrying costs are a little harder to understand,” Patty continued. “Your increase in inventory is mostly product on the shop floor or WIP. Last year there was almost no WIP, now there is about $4 million in partially finished product on the floor at anytime. This decreases your inventory turns from 17 to about 10. We were able to make these inventory turn estimates, because holding each week of inventory costs about 1% of the yearly cost of all of the inventory. The bottom line is that the WIP is killing profitability, the 5% cost adder for the responsiveness jobs doesn’t come close to making up for this loss.”

Hyper Phil moaned, and then rapidly said, “You’re saying that my being responsive to the customer campaign is a failure.”

“Not really Phil,” intoned The Professor. "Just be more careful in your implementation."

“Can you give an example?” moaned Phil.

“May I tackle this one?" asked Pete. “We did quite a thorough analysis and are convinced that you can implement 90% of your ‘responsiveness’ jobs and not negatively affect production,” Pete went on. "As an example, 4 ‘responsiveness’ jobs last week where started at 1PM and finished at 6PM, too late for the day’s shipments. They didn’t ship until 10AM the next day. They could have been assembled on the next shift, with no disruptive changeovers and no extra WIP hanging around.”

Patty added, “We believe that you should leave 5 of your 8 lines undisturbed to handle jobs with very large lot sizes and have three  lines for some large lot sizes and the ‘responsiveness’ jobs." 

“We can work with you to develop a plan to minimize changeovers and WIP while continuing to be responsive. Your shop flow should be organized more like a ballet than a hockey game, quoting Phil Crosby. You can be responsive and minimize disruption on the shop floor… a balance is needed,” she summed up.

“One thing to remember, is ‘Emerson’s Rule,’” The Professor interjected.

“What is that? everyone asked. 

“It is from my dear friend, Professor Bob Emerson of Binghamton University, ‘Never release a job to the floor unless you are committed to finishing it uninterrupted.’ Bob is an expert on inventory management, he knows the crippling cost of inventory if not well managed, especially WIP, which includes much added value,” The Professor finished.

The meeting broke up and Phil, Harry, and Jane gratefully thanking the trio. Patty and Pete agreed to stay for a few days to help Phil set up a modified production control system.

“Boy, I was surprised how well that was accepted,“ Patty confessed. 

Pete, who usually has insider info, responded, “Phil was told to work with us or else…. I guess he listened.”

On that note, Patty’s cellphone buzzed. It was her mother, with the latest wedding details.

Cheers,
Dr. Ron