Indium Corporation Blogs

Folks,

In my last post we saw how you could measure density with only a scale.  In this post, we will expand on that technique and learn how to measure metal content in gold/quartz ore.  In principle, this technique could be used for other ore, but the ores can only be two part (e.g. gold and quartz) systems.  Gold is a “natural” for this analysis as it is typically pure gold with quartz.

Gold is often found “veined” in quartz.  I was certain that this was the origin of the “Golden Fleece.”   The fleece being the white quartz with the gold on top.   However, a little research did not clarify this belief.

Anyway, let’s assume you take a few weeks off from work.  Leaving the world of solder paste, TIMS, ITO, wave solder flux and solder preforms behind, you set out for the west in search of some large gold nuggets.  Fate was with you in that, in a short time, you find a gold/quartz specimen as shown below.   The images, and the new “wet gold” weighing technique I will discuss, are from Bill and Linda Prospecting.

You are so excited you are shaking.  The only tools you brought are a scale, some string and a beaker.  To determine that gold content, you need to measure the weight of the gold in air and under water.  But you only have the scale as shown below.  What can you do?

After measuring the weight of the ore in air, fill the beaker part way with water, place it on the scale and zero the weight.  Then insert the ore on a string as shown below.  The scale will now read the weight of the volume of water that the ore displaces.  Let’s call this weight of the water displaced W_D .  The wet weight of gold (weight of gold under water) will be the weight in air minus W_D.  So we now have the weight in air and the weight in water.

The derivation of the equation that tells us how much gold is in the ore is at the end of this post.  The final equation we need is W_Au = 3.07W_W – 1.91W_Air.  For our ore sample W_Air = 25.1 pennyweight (pw). A pennyweight is 1/20^th of a troy oz.  W_D as shown in the photo above is 8.3 pw.  So W_W = W_Air – W_D = 25.1-8.3 = 16.8 pw.  So W_Au = 3.05*16.8 – 1.91*25.1 = 3.635 pw.  Subsequent analysis showed that the gold content was actually 3.9 pw and error less than 7%.  Not too bad for a simple field measurement.  At $1600/oz our ore sample contained. a little over $300 dollars of gold.

This technique could be used to measure the density of an alloy as in the last post.

Cheers,

Dr.Ron

The Derivation of the Equation

Folks,

A while ago I discussed the Weibull Distribution and its importance in electronics reliability analysis.  This distribution has been used to evaluate the life of solder joints whether formed in SMT, wave, or even using solder preforms. In the next few posts, I would like to discuss how to interpret Weibull plots.

Let’s consider two Weibull plots from thermal cycle testing of lead-free solder joints as seen below in Figure 1.

Figure 1.  A Weibull Plot of Thermal Cycle Data for Alloy 2 and Alloy 4.

Both alloys have almost exactly the same scale, or characteristic life. You will remember that characteristic life is the number of cycles at which 63% of the test subjects fail.  For Alloy 2 it is 2,593 cycles and for Alloy 4 it is slightly better at 2,629 cycles.  However, these two alloys performed dramatically differently.  The most striking difference is in their “spread.”  We see this much greater spread for Alloy 4, when we plot a fit to the data as a normal distribution, as in Figure 2 below.

Figure 2. The Best Fit Normal Distribution Plot for Alloy 2 and Alloy 4.

In the Weibull plot, the data for Alloy 2 has a very steep slope or shape factor, this indicates a tight distribution.  A tight distribution is desirable as it facilitates more accurate prediction of thermal cycle life.  Alloy 2 is clearly superior.  So, in a Weibull distribution, not only is a large scale factor or characteristic life desired, but so is a steep slope or larger shape factor.

Next time we will talk about outliers.

Cheers,

Dr. Ron

Folks,

Let’s step away from electronics assembly challenges, and deep considerations of solder paste, solder preforms, and wave soldering, to ponder where electronics have gone in the last decade or so. 

The mobile phone of the early 2000s was just that, a phone. Today it is a phone, music player, PalmPilot-type organizer, camera (still and video), video player, gamer, TV remote, GPS system, web portal, etc.  There is almost nothing electronic that it can’t do.  The USB memory stick of 2002 with 0.5GB of memory cost $500, today $5 will get you 4GB one, a cost reduction of 800 to one, the equivalent of halving in price about every year.

There is no reason to expect any less dramatic advancements in the future.  But, predicting the future of electronics is never easy.  In the January 2013 edition of Scientific American  Ed Regis wrote an article titled, The Bold and Foolish Effort to Predict the Future of Computing. In this article, Regis interviewed eight computer luminaries, including Stephen Wolfram and Nathan Myhrvold,  to ascertain their perspectives on where computing will be in 150 years.  The conclusion was that no one can predict the future of computing, as interviewee George Dyson said, “All I can guarantee is that any prediction will be wrong."

One person less humbled by the difficulties of computing predictions is Ray Kurzweil.  His prediction success level of more than 80% would seem to support such confidence.  Kurzweil also just got a new job at Google. I am finishing his new book “How to Create a Mind: The Secret of Human Thought Revealed” and, while I  finding it fascinating, I think he goes too far.  He believes the mind is a sophisticated computer and that, when computers get to a certain point equaling and surpassing the human mind's computational ability, they will be considered human.

Supporting this point, he hopes to, someday, resurrect his father, as Bloomberg states:

“Among the stranger things Ray Kurzweil will say to your face is that he intends to bring his father back to life. The famed inventor has a storage locker full of memorabilia—family photographs, letters, even utility bills—tied to his father, Fredric, who died in 1970. Someday, Kurzweil hopes to feed this data trove into a computer that will reconstruct a virtual rendering of dear old Dad.”

Call me a religious fanatic, but I think there is something more to each of us than our memories and our brains computing ability. 

Kurzweil endorses IBM's computer system, Watson’s victory in Jeopardy  in February of 2011 as a major step in the direction of computers as humans.  IBM provided commercial support for these Jeopardy episodes.  In the commercials they strongly reminded us that Watson was not thinking, but only doing what it (not “he”) was programmed to do.  Someone summed it up nicely, Watson won, but did he know he won?

I think there are a few major things that people like Kurzweil minimize when they propose that computers will be recognized as human.  These points are:

1. Humans are sentient (they would know whether or not they won or lost Jeopardy, we have emotions and feelings).  I know of no progress in sentience development for machines.
2. Humans have a will.  We get up in the morning, we decide what we will do that day and do it.  There is no progress (thankfully?) in giving computers a will.
3. Humans have a biological body.  We smell the newly cut grass, feel a refreshing breeze, get tired, enjoy a meal, enjoy sports etc.   It is easy for some to minimize the importance of the body in being human. Again no progress in this area.

However, I don’t want to minimize much of what Kurzweil predicts.  In her ground breaking book, Alone Together, Sherry Turkle tells us that, in addition to the fact that the average teenager in the US sends 200 text messages a day, electronic companions already exist.  As time goes by they will become more realistic and will be capable of interesting and stimulating speech and interaction.  Having all of the world’s knowledge at their fingertips (pun intended), these companions will likely be more stimulating than people, they will easily pass the Turing Test, and, for good or ill, will make us more “alone together” than ever.  But our companion will not love, fear, hate, or know that it is a companion.

As has been pointed out, this brave new world is coming whether we like it or not.

BTW, on another topic,  the History Channel has produced a terrific video series, Men Who Built America http://www.history.com/shows/men-who-built-america.  It is a the spell-binding story of Vanderbilt, Rockefeller, Carnegie, J. P. Morgan, Edison, and Henry Ford.  If you missed it, it is coming out in DVD in January.

Cheers and Best for the New Year,

Dr. Ron

Folks,

Let’s see how Pete is handling the wave solder crisis.

Pete had to admit that he was surprised by the positive outcome of his meeting with Fred Castle.  He had sent Patty a text the day before, after he took the operators to lunch, before meeting Fred.  The text was a little negative.  So he was eager to send her the good news about the surprises in his two meetings with Fred since then.  He was frustrated that he kept on getting her voice mail.  Finally she answered.

“Advanced Processes,” Patty speaking.

“Hey, kiddo, it’s your favorite process genius!” Pete responded cheerfully.

“Oh, this must be Oscar Patterson!” Patty joked, and they both laughed. Patterson was an annoying chap they had to deal with a few years ago.  He topped their list of most annoying people. Pete had almost come to fisticuffs with him.

“How is it going there?” Patty asked.

“Shockingly well. My meetings with Fred Castle were very productive” Pete answered.

“Well, that is shockingly positive news. But I thought he said, ‘I’ve forgotten more about wave soldering than you’ll ever know,’” Patty responded.

“That’s the first thing he said to me when we shook hands, but he was clearly teasing.  He slapped me on the back at the same time and chuckled. He went on to say that he had worked in wave soldering for over 30 years, typically at companies that had processes that were out of control.  It was clear that he understood a lot about wave.  We talked for 30 minutes about what makes a good wave process. As far as I could tell he was right on in everything he said.  I think the operators didn’t pick up on his teasing, by the way,” Pete elaborated.

“What about special cause vs common cause?” Patty queried.

“He didn’t have a clue,” Pete replied.

Patty was bracing herself.  She was concerned that Pete might have insulted Castle.

“And you didn’t tell him he was an idiot?’ Patty teased.

“Patricia! I’m shocked you could even think such a thought,” Pete replied.

Pete went on, “We bonded, and he admitted that he was frustrated with the yield loss increasing.  He was studying the situation and spending a lot of time trying to figure out the issues.  He said he was having trouble sleeping.  He mentioned that, in his last job, he was responsible for the wave processes at 10 locations.  He was constantly fighting fires and got good at it.  He had never worked at company that performed DOEs and developed optimized processes.”

“I’m dying to know how this situation worked out,” she interrupted.

“Patience, patience,” Pete admonished jokingly. He continued, ”It was clear that Fred likes to learn, so  I mentioned that, recently, The Professor had mentioned the importance of understanding the differences between common cause and special cause variation when trouble shooting a process.  I suggested that maybe studying these topics might help. So I gave him a few links to The Professor’s posts on common cause and special cause.” (Dr. Ron note, it will be helpful understanding this story to read The Professor's post, if you are not familiar with common cause and special cause fails.)

“What happened then?” Patty asked, the impatience in her voice apparent.

“Remember, this is now the end of my first day. I watched the process in the morning, took Molly and Chuck to lunch, and then met with Fred.  On the second day I had a morning meeting with the quality director, Pam. Then Castle and I went to lunch,” Pete elaborated.

“And?” Patty asked impatiently.

“Castle was all excited.  After studying common cause and special cause all night, he realized that he was seeing common cause fails in his detailed scrutiny of the wave line. By adjusting the process parameters slightly when he found a common cause fail, he was moving away from the optimized process settings that were determined by a DOE, so the failure rate got worse.  In his previous job, he was mostly seeing special cause fails, as the processes were not optimized, so he was used to intervening,” Pete explained.

“It seems like he won’t have enough to do now,” Patty commented.

“I suggested he help quality.  They are stretched thin and he is a detailed-oriented fellow.  He keeps meticulous Pareto charts of the fails,” Pete said.

So, where are things now?’ Patty asked.

“Yesterday and today, first pass yields are at 96%.  Fred also started helping quality today. It felt good to help and not offend,” Pete finished.

Patty thanked Pete for the great job he did and complimented him strongly for being successful and making friends at the same time.  As she hung up the phone, she saw an email from Pam Olinski in her in box.  It was a kind note thanking her and Pete for his help.  It recounted much of what Pete had said.

She wistfully looked out her window.  She was happy and grateful for all of her success, but, to be truthful, she missed the action of being out on the shop floor solving these types for problems.

She was jolted from her chair when she suddenly remembered it was her turn to take her twin sons to karate lessons.  So she packed up quickly to pick them up at her mother-in-law's, to get them to the gym by 5PM.

Cheers,

Dr. Ron

image

Folks,

It's been a while. Let's look in on Patty......

Patty stared, bleary eyed, at her laptop screen.  It was the day after the election.  She and Rob were following the election closely as a “statistical thinking” exercise.  They had met at a conference with The Professor in late October and agreed that following the election would test their statistical thinking skills.  They established beforehand that they would not discuss who they favored, just the data.

All agreed that Mitt Romney had a greater challenge than President Obama.

As Rob said, “Of the six most populated states, even the Republicans agree that Obama will win California (1), New York (3), Illinois (5), and Pennsylvania (6).  Romney is only a shoe-in for Texas (2).  Only Florida (4) is a toss up”

“I thought some analysts were saying that Pennsylvania is in play,” The Professor commented.

“They’re dreaming,” Patty said with conviction.  “Pennsylvania has too many big cities; typical democratic strong holds,” she continued.

“Many pollsters have 255 electoral votes in Obama’s column and only a little over 200 for Romney. It’s hard to see a Romney path to victory.  It is statistically unlikely he could win all of the swing states” Rob added.

The Professor beamed as he listened to his protégés' intelligently analyze and argue the situation.

They all agreed that it was hard to understand why many were referring to it as a close race, although voter turnout could change everything.

As election night went on, Patty felt she could call the election at 8PM EST.  However, she was sympathetic that the networks needed a high level of certainty. The major networks were finally calling it at 10PM.  When they did, Romney was ahead in the popular vote by about 1 million.  Patty chuckled to herself, when a renowned TV anchor commented that it might be a governing challenge to Obama to win the electoral college and not the popular vote.  Clearly he had not factored in the fact that, although California was “called” for Obama around 10PM EST, it was called with only a few percent of the votes in.  The networks were using exit polls and statistical analysis to make a projection.  By the time all of the west coast votes were counted, Obama will comfortably win the popular vote - because of California’s large population.  Patty thought this should be obvious to the pundits.

Patty had stayed up until about 11PM to watch the results.  It was comforting that her analysis was spot on.  However, she was so “wound up” that she couldn’t fall asleep and she was now paying the price.

As her attention shifted back to the email she was writing.

Suddenly, she was jarred by a loud, cheerful voice.

“Hey kiddo, pack your bags, looks like we’re on the road again,” Pete said loudly.

As usual Patty thought,” How does Pete always know these things before I do…..I’m the boss!”

“What’s the scoop?” Patty asked.

“Remember our facility in Ohio?  They are having wave soldering yield and throughput problems,” Pete answered.

“What!” Patty shouted.  “We spent a lot of time there six months ago optimizing their wave soldering operation and teaching them the appropriate use of solder preforms. What happened?” She finished.

“Not sure,” Pete responded. “I thought we worked really well with their team and developed a good process.  It seemed to me it was one of the more productive projects I was involved in in quite awhile,” Pete finished.

“And you didn’t even offend any of the senior managers,” Patty teased.

Pete chuckled but his cheeks did turn a little red.  Pete was a terrific process engineer, but he had a little bit of a “short fuse,” although he was usually right.

“In talking to some of my buddies there, they told me that senior management hired a very senior fellow who is considered an expert in wave.  Strangely, things fell apart right after he joined,” Pete explained.

“Well, you are on your own for this one.  I've got a number of family commitments over the next two weeks,” Patty said with a little sadness in her voice.  Patty enjoyed these types of challenges.

“As soon as I get the official request, you’ll be on your way,” Patty said.

“Oh, and don’t offend anyone,” she teasingly finished.

As Pete left her office, she checked her emails. Sure enough, there was a note from Mike Madigan asking her to intervene in this wave soldering problem.

Two days later Pete was in ACME’s Ohio facility sitting in the office of Pam Olinski, the site's quality manager.

“Pete, I’m so glad you could come.  Three months ago our wave soldering first pass yield was 95% and our production was about 2,000 boards per day.  Yield is now 90% and production is off 15%. “Help!” Pam said.

“Tell me about the new guy?” Pete asked.

“Fred Castle; he has very impressive credentials, but he has been running the wave process like a dictator. He stops the process a lot to adjust the wave machine.  I think he will be offended that you are here to audit the process,” Pam finished.

Because of this concern, they agreed that it might be best to have Pete initially view the process from afar.  So, they decided that Pete would be given an operator’s smock and walk around the shop floor for half a day or so.

As Pete arrived on the shop floor, almost immediately he saw Fred stop the wave machine and make some adjustments.  While  making the adjustments, Fred held a board in his hand - and he looked at occasionally.  After the wave machine was running again, Pete saw that Fred looked carefully at every board.

Pete saw one of the wave operators was going on a break.  Pete remembered Molly Stark from his visit to optimize the wave process six months ago, so he stopped her and ask if she could join in for lunch.

The morning passed quickly, and Pete was off to lunch with Molly.  As Pete had suggested, Molly brought another operator, Chuck Petrus to lunch.  Pete insisted on treating, so Molly and Chuck left their brown bags behind. 

In total, Fred stopped the line four times during the almost 4 hours of Pete's observations. Each time he made adjustments on the wave machine. After exchanging pleasantries Pete asked, “Why was that fellow stopping the wave line so often?”

Molly got quite animated and answered, “That’s Fred Castle, the supposed wave genius. He stops the line every time there is a defect and adjusts the wave machine parameters.  A number of us complained to him that he shouldn’t make adjustments on the machine that with just one fail.  That’s what you taught us.”

“What did he say?” Pete asked.

“ ‘I’ve forgotten more about wave soldering than you will ever know’……No one has said a word since,” Chuck responded.

“You and Patty taught us about special cause and common cause variation. I don’t think Fred understands that,” Molly commented.

“He’s also a knob twiddler,” Chuck added.

Does Fred know the difference between common and special cause variation?  Is that the root of the yield and throughput problems? 

What is a knob twiddler? Stay tuned to find out.

Cheers,

Dr. Ron

If you have ever witnessed one of our NanoFoil^® demonstrations at a tradeshow, you may remember we used a 9-volt battery to activate the material. Yes, it can be that simple – especially for parts less than 15cm in bond diameter or bond length.

For large area bonds, it is recommended to use multiple ignition points to coordinate the reaction. We bond many large area assemblies at Indium Corporation, and our go-to tool for activation is the MPIS (Multi-Point Ignition System). This system can monitor and apply voltage to 16 points simultaneously. Depending on application, we use a number of channels to ensure the NanoFoil^® is activated in at least 15cm intervals. This coordination of activation points controls the wave of reaction, causing the waves to meet – which reduces voiding and solder splash. More about the reaction can be found here.

*This post is part of the NanoBond^® Process series

One of the key points to understanding a NanoBond^® application is understanding the reaction that takes place. When NanoFoil^® is activated, the nickel and aluminum bilayers (picture on left) start a self-sustaining reaction that quickly consumes the material.

After the reaction takes place, the aluminum and nickel layers form a brittle intermetallic (picture on right). This bi-product, nickel aluminide, shrinks and cracks allowing solder to flow between and complete the interconnection.

Through a series of posts, we will discuss:

• Wave Propagation
• Heat Penetration
• Heat Dissipation

I know this doesn’t cover everything you’d ever want to know about the reaction of NanoFoil^®, but that’s what we are here for! Let us know if you have a question.

*This post is part of the NanoBond^® Process series

Printed circuit boards containing both surface mounted and through-hole components are common, and are often referred to as "mixed technology" boards.  In mixed technology assembly, solder paste is used to attach the components to the surfaces and wave soldering attaches the components that are inserted through holes in the board.  For low volume production, hand soldering is often utilized - for the attachment of through-hole components.  Both of these methods require additional steps after the original reflow of the solder paste.

To increase your profits (saving you time and money while improving your quality and productivity) InTEGRATED PREFORMS^® have found a place in mixed technology assembly.  InTEGRATED PREFORMS^® are interconnected solder washers, designed to fit the pin pattern of a through-hole component.  These arrayed solder washers are sized to deliver the precise solder volume required to fill the holes and to produce excellent solder fillets at each joint. 

In some cases, to add even more solder, solder paste is deposited over the holes and the InTEGRATED PREFORM^® is placed into the paste. The component is then inserted through the solder preform, the solder paste, and the hole. 

In other applications, TacFlux® (that is compatible with the solder paste's flux vehicle) is applied to the preform before it is placed on the component's pins, or is placed directly on the board, and the component is inserted as described above.  Whichever method is used, only one reflow step and only one cleaning step are required.

In traditional wave soldering, components with long pins are a special challenge because they are very difficult to attach without getting alloy on the pins during wave or hand soldering.  InTEGRATED PREFORMS^® can be applied to the top or bottom side of the board and are reflowed along with the components held down with solder paste.

InTEGRATED PREFORMS^®  are designed and built to address the unique characteristics of each specific application.  To build your InTEGRATED PREFORMS® we require the following information, so the solder volume and washer spacing are correct for your specific pin configuration:

• Hole size
• Pin size
• Board thickness
• Center to center spacing of the pins (within the row, and row to row)
• Solder Alloy
• Is the preform going to be used to add to the volume of solder from the paste?

Separate (individual) solder washers can also be used in place of connected InTEGRATED PREFORMS^®.  They can be designed to deliver the same consistent volume of solder required for each joint.   Care must be taken, however, to place only one preform on a pin, and not miss any.  This is what makes InTEGRATED PREFORMS^® desirable.  The solder washer array is designed and manufactured to fit the pin configuration so only one washer goes on a pin.  If extra solder volume is required, InTEGRATED PREFORMS^® can be easily stacked.

With today's drive to optimize profits, InTEGRATED PREFORMS^® present an excellent opportunity.  The biggest advantage of InTEGRATED PREFORMS^® is the fact that quality can be improved while costs are reduced.  If you are looking for any easy way to cut costs, increase production, improve quality, improve customer satisfaction, and, ultimately, increase your profits, talk to me about InTEGRATED PREFORMS^®.

Paul Socha psocha@indium.com

BONUS: Read our white papers regarding InTEGRATED PREFORMS^® .

Ultrasonic Testing (UT), performed by acoustic microscopy, is a great way to determine the quality of a solder bond without destroying the assembly.

As a very basic description, SAM (scanning acoustic microscopy) uses sound waves to travel through the assembly, much like some animals use sonar to locate objects. Sound waves generated by a transducer travel through the assembly and bounce back when they encounter different materials. Air reflects back much differently than metal, so, by using sound waves, we can locate pockets of air (voids).

In a NanoBond^® you can expect to see 2 things:

1) darker spots where the NanoFoil^® is located in the bond and

2) very little voiding, which will appear as white areas. Here is an example of voiding:

Most of the time we see little or no voiding. We typically achieve <2% when we bond sputtering targets with NanoFoil^® in-house. Here is an example:

If you have experience with traditional large area soldering methods, you will notice that <2% voiding is a sign of a very good bond.

For sputtering targets this is necessary to reduce pump-down times and eliminate ‘virtual leaks’. Contact us if you are interested in learning more.

*This post is part of the NanoBond^® Process series

To successfully use NanoFoil^®, you do not need to fully understand what it is or how it is made, although that does help.

It also makes for a very interesting story…

What is actually critical for you to use NanoFoil^® is to fully understand the NanoBond^® Process. This process consists of:

1. Design Considerations

• Choosing the Best Metallization
• Adding Solder to a NanoBond^® Assembly
• Flat Bonding Surfaces

2. Setup

• Surface Preparation
• NanoFoil^® Thickness
• NanoFoil^® X and Y Dimensions
• Aligning the Assembly
• Pressure During the NanoBond^® Process

3. Activation

• Laser Activation
• Electric Activation
• Thermal Activation

4. Reaction

• Wave Propagation
• Heat Penetration
• Heat Dissipation

5. Testing

• Ultrasonic Testing
• Cross Sectioning
• Shear Testing

This is a new process for most people, but not for our worldwide Technical Support team. Our engineers are experienced with this technology, and can help you set up the NanoBond^® Process. If you need help, or would like to learn more, support is only a click away.

We also offer NanoFoil^® research kits, so you can try this out for yourself.

Folks,

This year will mark the 10^th anniversary of SMTA’s SMT Process Certification Course.  This course was developed by Jim Hall, Phil Zarrow and me, Dr. Ron Lasky, in time for SMTAI 2002.  The workshop covers all of SMT from materials (strong emphasis on solder paste), components, soldering, stencil printing, component placement, reflow soldering, wave soldering, dispensing, test, and more.

The course assumes that the material is mostly review, so it is definitely not introductory level.   At the end of the workshop are an open book and closed book test.  Upon passing the test, you will have the privilege of adding the title: “Certified SMT Process Engineer*” to your business card.

Among the many benefits of SMTAI certification is being able to inform your customers that your product is manufactured by credentialed personnel. Since the SMT Process Certification Course is taught internationally, this credential is recognized globally.

So if you, or your team, are not already certified, join the tenth anniversary workshop at SMTAI 2012  at Disney World and get certified!

Cheers,

Dr. Ron

* In some countries, such as Canada, the term "engineer" has legal implications and cannot be used unless the person has a degree from an accredited university or a Professional Engineer's License.

最近有一个客户向我们展示了他们公司新采用的“自动售卖机”库存管理系统（industrial vending machine）,真是大开眼界。在此和大家分享一下。 请看下面的图片。

这个自动售卖机和我们平时看见卖零食的机器表面上没什么大区别，最多是可以在机器旁边衍生多些大格子储存更多的货品。客户的采购员自豪的向我们介绍了采用这套系统后带来的好处（当然，所有好处都是围绕降低成本和容易系统管理）

• 免费机器，一年6%的rebate
• 拿到物品开始算钱: 员工凭自己的门卡在机器上取到需要的货品后，供应商才开始计算物品单价。月结。换言之，在机器上的所有物品，只要客户没有从机器中取出，供应商都不收客户钱。
• 网络监控管理：
  • 采购人员可以在机器上设置好，对所有物品的取出，谁取出，每次、每天取出多少，都可以通过机器变好程序，设置好。这样管理，知道谁拿了什么，减少浪费。一个很简单的例子：几种擦拭机器的不同牌子的纸，表面上看都一模一样，其实有一种是5分钱一张，有一种是1.5元一张。 1.5元一张的确实特别好用，某些特殊机器就是要用这种贵纸才能擦干净。采购员买了两种都放在车间。但是车间人员不知道差别，大家都随便取用，有时候用贵的纸什么都擦，甚至擦鼻子：-） 现在有了vending machine, 就可以控制只有擦贵机器的人才可以限量取到贵的纸。
  • 采购人员可以在网上实时监控，知道每种货品每个时间段的用量，谁用了、用了多少，机器中还剩下多少等。以前，很多公司的采购人员只能通过预算购买下一次的货品，但是他们对现存货品剩下量的多少，没有实时资讯，所以造成了很多取货现象。
  • 通过网络在线订货购买

看到介绍后我们都很感慨，觉得做这个vending machine的公司十分有创新性。而且那么优惠的条件（免费机器，“0”库存，年底的rebate）, 这些都是等于把现金都压在了客户那里。这个公司一定要有雄厚的实力和足够多和大的客户，才能利用规模相应(economic scales),不然毛利这么低，怎么赚钱……

我们还谈到了焊接产品(soldering materials)。目前，客户准备把焊锡棒（solder bars）和锡线 (solder wires)放在vending machine中管理，但是焊锡膏、焊锡球、助焊剂等（solder paste, solder spheres, wave fluxs）不能放, 因为solder paste 要特别的冷冻储存条件；spheres不易过多的人工操作，让小球们在瓶子里碰撞；wave flux的容器比较大，难放入vending machine……

Cheers！

Image Source

在平时和客户们的会议交流中，因为Indium公司的产品线比较广，不同的客户群常常有针对自己独特的应用或是技术、销售服务等各种问题。

刚刚开始正式做一线销售，我有时候在会议前会有点紧张（特别是新的客户），怕自己回答不上客户的各种问题，帮不上忙。但是后来老练了一点，即使有些问题我自己真的不懂或是即时没有答案，但是总是可以“follow up”跟进的。会后积极主动利用各种资源找出答案，及时回复客户就好了。 现在的会议中， 我更会了“审时度势”的提问，从客户口中问出对项目、生意有用的信息。

最近我们在联系一个国际大客户做一些项目。 客户要求我们的科研副总裁李宁成博士(Dr.Ning-Cheng Lee)过来和他们交流，做一个roadmap meeting. 客户还提出相关的内容请李博士来讲。在我们和李博士内部交流后，决定先向客户提问，问清楚他们的需求后，我们才好“对症下药”。 比如说，客户想了解低银合金Low Ag Alloy, 低温合金在波峰焊中的使用Low Temp Alloy for Wave Soldering，微间距印刷0.3mm fine pitch printing等等。我们知道客户已经在使用别的供应商的SAC0307的低银合金了，并且客户的NPI工厂里没用波峰焊，但是为什么客户会叫我们来介绍呢？对现在的SAC0307合金不满意？哪些性能不满意需要改进呢？波峰焊又是怎么一回事呢？等等。 所以，我们也决定向客户提问，问清楚他们为什么有这些“需求”，真正的原因是什么……

有一个销售同事更有意思，当我告诉他我有一个做激光设备的客户（他们在使用我们含铟金属的材料），有一次我被客户的几个“资深工程师”追问关于铟金属的一些不太相关的问题，我根本不知道答案……我的销售同事建议说，以后出现这种情况，当你觉得他们问的东西有点过的时候，你可以反问他们一句“Why you asked this question? Why you want to know?”  这样就可以尝试挖掘出客户问问题的真正目的了。当然，要见机而行!

Cheers!

Pic: Google Image

Folks,

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

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

While visiting the five factories, she tried to learn why those that had a poor NMAC/I/O were performing poorly. After a little checking, she and Pete discovered that the poor performing sites typically had lines that were not time balanced, had slow component placement machines, and occasionally had very slow printers or solder paste with poor response to pause. There was even one plant that was using a full wave solder process, when only 8 solder preforms would have done the job in the reflow process. None of these “problems” would show up if you were only tracking line uptime. In light of this situation, she also developed a plan to use NMAC/I/O to identify and implement opportunities for improvement.

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

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

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

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

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

Patty’s cell phone vibrated, but she ignored it.

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

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

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

“Precisely,” Patty responded.

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

Patty’s cell phone vibrated again.

“Exactly,” Patty commented.

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

“It is nearly perfect,” Patty said.

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

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

Patty thought this was something to discuss with the Professor.

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

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

Cheers,
Dr. Ron

Folks,

I’m taking a few moments from Wassail Weekend , held annually in my village, Woodstock VT, “The prettiest small town in America”, to write a post about last week’s workshops at ACI.

Indium colleague Ed Briggs and I gave a 3 hour presentation on “Lead-Free Assembly for High Yields and Reliability.” I think Ed’s analysis of “graping” and the “head-in-pillow” defect is the best around. 

There was quite a bit of discussion on the challenges faced by solder paste flux in the new world of lead-free solder paste and miniaturized components (i.e. very small solder paste deposits.) One of the hottest topics was nitrogen and lead-free SMT assembly. There seemed to be uniform agreement that solder paste users should be able to demand that their lead-free solder paste perform well with any PWB pad finish (e.g. OSP Immersion silver, electroless nickel gold, etc.) without the use of nitrogen. Not only does using nitrogen cost money, but it will usually make tombstoning worse. However, in the opinion of most people, nitrogen is a must for wave soldering and, since it minimizes dross development, it likely pays for itself.

After Ed and I finished, Fred Dimock, of BTU, gave one of the best talks I have ever experienced on reflow soldering. He discussed thermal profiling in detail, including the importance of assuring that thermocouples are not oxidized (when oxidized they lose accuracy). He also discussed a reflow oven design that minimizes temperature overshoot during heating, and undershoot when the heater is off. Understanding these topics is critical with the tight temperature control that many lead-free assemblers face.

Fred Verdi of ACI finished the meeting with an excellent presentation on “Pb-free Electronics for Aerospace and Defense.” Fred’s talk discussed the work that went into the “Manhattan Project.” A free download of the entire project report is available.

There appears to be agreement that acceptable lead-free reliability has been established for consumer products with lifetimes of 5 years or so, but not for military/aerospace electronics where lifetimes can be up to 40 years in harsh service conditions. These vast product lifetime and consequences of failure differences are depicted in the Fred's chart (above). Commercial products are in quadrant A and military/aerospace products in quadrant D.

One of the greatest risks faced by quadrant D products is tin whiskers. Fred spent quite a bit of time discussing this interesting phenomenon. One of the challenges of this risk is that there is no way to accelerate it, so you can’t do an equivalent test to accelerated thermal cycling or drop shock. Fred mentioned that there have now been verified tin whisker fails, the Toyota accelerator mechanism being a confirmed one.

In addition to tin whiskers, lead-free reliability for quadrant D products (with a service life of up to 40 years) in thermal cycle and other areas remains a concern.  I mention that tin pest was not on the list of issues for this quadrant.

Fred and the Manhattan Project Team have identified many "gaps" that need to be addressed to determine and mitigate the risk of lead-free assembly for quadrant D products.  They plan to start this approximately $100M program in 2013.

For those that missed this free workshop, ACI host Mike Prestoy is planning another one in 6 months.

Cheers,

Dr. Ron

Folks,

The Guadalajara (GDL), MX Chapter of the SMTA held their first meeting on November 9 and 10 at CETI in GDL.
Approximately 70 engineers from local companies attended. It was a great success. 

The agenda was:

November 9^th, 2011

0830-0900am    Registration and Exhibits Open

0900-0915am    Welcoming Remarks and Exhibition starts

0915-1045am    Inventec: “Reliability Assessment regarding Flux residues"

1045-1215pm    Sanmina-SCI: “Capabilities of a Failure Analysis Lab”

1215-1315pm    LUNCH

1315-1445pm    DEK: "Optimizing the Print Process for Mixed Technology"

1445 -1615pm   Vitronics Soltec: “How to Choose a Robust Configuration for Equipment
                          for Defect Free Soldering - Reflow, Wave and Selective”

1615-1745pm    KIC: “Fixing Reflow and Wave Related Defects as Well as How to Avoid 
                          Them in the First Place”

 November 10^th, 2011

0900-1030am    Sanmina-SCI: “Process development of 01005 components”

1030-1200pm    Indium: "Lead-Free Assembly for High Yields and Reliability."

1200-1300pm    LUNCH

1300-1430pm    Universal Instruments: "Tutorial on Failure Analysis"

1430-1600pm    Zestron: “PCB cleaning before conformal coating”

1600-1730pm    Kester: “Understanding Soldering Chemistries - Reducing Costly
                          Defects, Increasing Yields and Reliability.

I spoke on “Lead-Free Assembly for High Yields and Reliability." We had several raffles and gave away autographed copies of my book “The Adventures of Patty and the Professor,” which has just recently been formally published. 

As usual, I had dinner at Santo Coyote, one of my favorite restaurants, however my Mexican friends also took me to Sacromonte, claiming it had better food. They were correct. I was convinced to try chicken mole which I liked. It is tough to beat Santo Coyote’s ambiance, however.

I can’t cite data for this, but I am quite sure that GDL has the largest number of workers in electronics assembly outside of Asia. It is great news that they now have an SMTA chapter to help the local engineers network and continue to grow in their skills.  It was great to play a small part in this success, but most of the credit must go to Indium Corporation’s Ivan Castellanos who is chapter president and Kester’s Miguel Vazquez, chapter vice president.

Cheers,

Dr. Ron

Anyone who has used wave soldering to assemble PCBs knows about that chunky layer of metal that collects on the smooth surface of the molten solder. This is solder dross; it is composed of oxidized metals and impurities that collect as the molten solder contacts the air and manufacturing environment. This happens regardless of alloy and is a normal part of the process, often consuming up to 50% of the bar solder added to the solder pot. In the past, this dross was collected as waste and disposed of, but solder dross is more than 90% valuable metal. This value should be recovered.

Nowadays, typically, this dross is collected and returned to a metals supplier for recycling. Indium Corporation now offers two programs for recycling solder dross. The first program involves simply sending back dross waste in return for a portion of the metal value as a credit. The second option involves sending back dross, which is converted to bar solder (within the original spec) and returned, with you paying only a fee for processing. When dross arrives, regardless of which program is chosen, it is electrolytically refined and the pure metals are recovered and converted back into usable bar solder. Often, this reclaimed/recycled metal has a better purity than virgin metal.

Dross is not the only form of solder that can be recycled. For instance, when changing to a different alloy in a wave soldering process, the entire solder pot will need to be emptied. The old alloy can be collected and recycled, lowering the amount of capital necessary to switch alloys. Bar solder and wire that have not been used within the shelf life can also be recycled to get back some of their value.

Contact me if you want to discuss this.

Folks,

In a recent posting we discussed that the higher melting temperatures of lead-free solder require reflow soldering temperatures to be higher, thus more electricity is used in lead-free assembly. However, as we calculated, this increased use of electricity is very small compared to all electricity used in the world.

An additional concern that some have voiced is the claim that RoHS, with its lead-free requirement, actually makes the environment worse because more tin and silver is used in lead-free solders.   They argue that the increased use of these metals, creates mining pollution and has driven the price of these metals sky high. Let’s examine these claims.

Prismark has estimated that approximately 90,000 tons of solder are used in electronics, with about 80,000 used in wave soldering and 10,000 tons for SMT soldering. It is important to remember that electronics solder is a subset of all solder. All solder (alloys for brazing pipes etc) uses about 190,000 tons of tin. Solder is the single largest user of tin. See Figure 1. 

Figure 1. Solder is the largest end use of tin. Tin is the base material for almost all solders. 

If tin-lead solder were still used predominantly, approximately 57,000 tons of tin (90,000 x 63% tin) would be used annually. With lead-free solder, about 88,000 tons (90,000 x 98% tin) of tin are used per year. This is an apparent increase of about 30,000 MT of tin used each year. However, an interesting thing to consider is that lead-free solder is about 14% lighter than tin-lead solder. Knowing that, and knowing that solder used in wave soldering (remember wave soldering accounts for almost 90% of all solder used in electronics assembly) is consumed by volume not weight (i.e. assuming approximately the same fillet size), about half of this increase is canceled out. 

This is all a bit confusing however, so it may be best to just to look at tin use. According to the United States Geological Survey (USGS), about 300,000 tons of tin are mined each year. Figure 2 is a graph of world tin production at mines per year (this graph does not show recycled tin.)  The amount of refined tin used each year in the US is depicted in Figure 3. Figure 3 includes about 15,000 tons a year of recycled tin. Recycling solder is very cost effective. Scott Mazur just pointed out (Printed Circuit Design and Fab and Circuits Assembly, p 36, August 2011), that recycling solder dross is 10 times as cost effective as recycling aluminum cans.

Looking at these graphs, it is hard to say that the amount of tin used has gone up since RoHS. It would appear that tin use is likely more affected by the economy and that it is really difficult to see an effect from RoHS’s July 2006 enactment.

Figure 2. World Tin Production at Mines. 

Most wave soldering solders have low or no silver. So, about 3% of the 10,000 tons of SMT solder, or 300 MTs of silver, are used in electronics. This is about 1.5% of the 22,000 MTs of silver produced each year. Silver use in electronics does not make anyone’s list of top silver usage.

Figure 3. US consumption of tin has decreased since RoHS was enacted.

So electronics solder use since RoHS has not caused tin use to increase, nor is it a significant factor in silver use. Therefore it is highly unlikely that electronics' use of tin or silver has been a prime driver in their stunning price increases in 2011.

Folks,

Here is an interesting turn of events related to the reliability of lead-free (Pb-free) soldering reliability. 

I was reminded recently by something Carl Sagan said, or, actually, did not say: Billions and Billions Although this term is strongly associated with him, he never said it. Sagan believed that this term was connected to him because Johnny Carson mimicked him and used the term.

 
Although not even close to being in Sagan's league, I find that I am now equally unfairly associated with the term,  "lead-free solder is a grand success." This came about in an interview by Rob Speigel, which he summarized in a blog post.

In reading Speigel's post, you will see that,  "lead-free solder is a grand success," is Rob’s term, not mine. Well, Rob's post resulted in a string of postings on IPC’s Technet .

One person opined:

Irresponsible statements like "lead-free solder is a grand success" should NOT be ignored. Those who make such statements in the face of all of the contrary evidence should be noted, and treated as motivated only by greed. Lead-free soldering certainly has been known for many "thousand$" of successes.

I have learned that it is not even worth the bother to refute such statements with those who make them. It may be a "grand success" for PhDs who contract to solder paste companies, but it certainly has not been a "grand success" to literally thousands of companies dealing with the reliability elephant sitting in the room getting larger by the day, and the associated fallout as a result.

Ouch!

Another shared:

I disagree with the stated and implied affect of RoHS, on PWBs expressed in this article. Lead free assembly reduces reliability by 50%. There can be no doubt about that. There are too many studies that confirm lead free assembly significantly degrades reliability. There are so many studies that demonstrate a reduction in reliability that Rod's contention is almost laughable. We are now faced with increased failures of copper interconnections and dielectric material due to high assembly temperatures. There is an increase in crazing that can support CAF, significant copper dissolution, and cratering in assembly, Switching to lead free in most HDI applications is a significant challenge. Lead free assembly has a profound affect by degrading PWB's organic component (epoxy) due the temperature required and copper interconnection and also the exaggeration of the z-axis expansion of the dielectric.

I have asked for copies of the many reliability studies referred to. No response yet.

Finally someone hit the heart of the matter:

I'm curious if "grand success" were Dr.Lasky's words or Rob Spiegel's editorializing. Lasky does mention the lack of long term results, and Speigel, in the comments,  enumerates a number of reliability problems. ISTM that neither truly believes  those words.

Correct!, Thanks. 

Here was my response that I posted on Technet:

Folks,

Pete is correct. I never said lead-free implementation was a grand success. These were Rob's words in his blog post. 

I have said repeatedly that adequate lead-free reliability has been demonstrated for consumer products like mobile phones, PCs, portable electronics with service lives less than 5 years. This level of reliability has been demonstrated in numerous studies and more importantly with field data. Vahid Goudarzi, of Motorola, stated that field reliability of lead-free assembled mobile phones has been equal or better than leaded assembly units. His data go back to 2001 (not 2006. Motorola started early for reasons discussed below).

 The reason Motorola shipped early with lead-free products is due to the fact that lead-free solder does not spread as well. Because of this poorer spreading, Motorola was able to decrease lead spacings without getting shorts, thus increasing the amount of electrical function in a smaller space. Since increased function in a smaller space is the defining attribute of portable electronics, the importance of this lead-free advantage cannot be overstated. Admittedly, lead-free's poorer wetting is a challenge in other regards, especially hole fill in wave soldering, but the Motorola Droid X2 could not be assembled with leaded solder, there would be too many shorts. Since the packaging density of the iPhone and similar devices is on a par with the Droid X2, I suspect this statement is true for most mobile products.

I have also repeatedly stated that lead-free reliability for long term service, mission critical devices has not been demonstrated. As a result, these types of devices should not consider lead-free solder at this date.

I regularly discuss these topics in my blog (http://blogs.indium.com/blog/an-interview-with-the-professor). The most recent post shows a striking photo of leaded solders spreading -which is too "good" for portable electronics.

Cheers,

Dr, Ron