Dr. Lasky’s Blog
Recent Entries
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Are You Ready for SMTA Process Engineer Certification (With Solution Update)
August 24th, 2008
Folks,
Since 2002 SMTA has had an SMT Process Engineer Certification Program that was developed by Jim Hall, Phil Zarrow and me. Some folks are a little nervous about taking the workshop and exam. In light of this concern, I have been asked by the Ohio SMTA chapter to give a 5 hour workshop on the types of problems one would be expected to solve. I have proposed a list of problems to be covered in the workshop. Here is a typical one that I might use. See if you can do it.
Component placement is the limiting process in an SMT line for throughput. Throughput (cycle time) is now one board every 50 seconds, when the line is running. There is one chipshooter (CS) and one flexible placer (FP). The bill of material (BOM) is 300 passives, 24 SICs (simple ICs), 8 CICs (complex ICs). The chipshooter is taking 50 seconds and the flex placer 20 seconds. All passives are being placed by the CS. The FP places CICs in one second. It places passives and SICs at the same rate.
1. Maximum throughput will be obtained when the CS and FP take the same amount of time. This can be accomplished by moving passives from the CS to the FP for placement.
a. What is the minimum cycle time if the line is balanced?
b. How many passives were moved to the FP to achieve this cycle time?Note: We assume all other processes can keep up with the new and improved cycle time.I will publish the solution in a few days. I expect to be giving this workshop quite frequently in the future.Solution:The FP takes 20 seconds to place the SICs and the CICs. The 8 CICs take 8 seconds, so the 24 SICs must take 12 seconds. Hence, the placement rate for SICs is 2 per second. The CS places 300 passives in 50 seconds, so it places 6 passives a second. Since the CS takes 50 seconds, to balance the line we must move passives to the FP. Our goal is that the time spent by the CS is the same as the FP. Let us assume that the number of passives we have to move to the CS is x, then time balancing can be expressed by the equation:tcs = (300 -x)/ 6 sec = tfp = 20 secs + x/2, solving for x: 300 - x = 120 +3x => 4x = 180 => x = 45So 45 passives are moved from the CS to the FP, hence the cycle time is now: (300 -45)/6 = 42.5 sec.The solution was quickly verified by LineSimulator(TM) software I developed. If anyone would like a copy of this software tool, send me a note at RLasky@indium.com.Cheers,Dr. Ron -
Meet the Bloggers at SMTAI
August 19th, 2008
Folks,
Well, I arrived at SMTAI a few days early to take my wife, daughter and two granddaughters to Disney World. We averaged 7 miles of walking a day, Friday through Sunday. My 2 year old and 4 year old granddaughters had a great time. However, we learned that the 3D movie, "Honey I Shrunk the Audience" is a little too scary for a 2 - 4 year old.
It ends up that mid August is a good time to visit DW, as many families have stopped coming as they prepare for their youngsters to attend school.
The weather was also mild (i.e not extremely hot and humid) as a prelude to tropical storm Fay. So my family had 4 good days of touring, before the strong rains came.
The Show? The tech sessions and workshops seemed quite well attended on Sunday-Tues. Hot topics: the need for recycling driving "design for disassembly, counterfeit components, and conversion of lead-free alloys to a few standards seemed of interest to many.
Sadly, it looks Fay has reduced traffic on the show floor as I write this note on Tues afternoon.
If you are here and can make it, join us at our "Meet the Bloggers" meeting on Wednesday, August 20 at 11AM at Indium's booth # 517. It should be fun. Five of Indium's bloggers will be there.
Cheers,
Dr. Ron
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Alloy Density Calculator Goes Live
August 8th, 2008
Folks,
Over the past few years I have been surprised at the interest in the Excel based alloy density calculator that I developed. Thanks for your interest!
In light of this interest, team Indium suggested that it be made available on the web for all to use. Find it here.
I have written some other software that I will be discussing in future posts. One even perfroms the calculations to time balance the component placement machines on a line. Another matches the solder paste spec to the reflow profile. Stay tuned.
Cheers,
Dr. Ron
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Dr. Ron Gets Second Eagle in Golf in a Year
August 4th, 2008
Folks,
Lest I seem braggy, one thing must be made clear. In general I have never been a good athlete. I can not get my body coordinated enough to make a "layup" in basketball, and I was never really a good baseball or football player. I am the most inefficient swimmer on earth, being able to swim only 50 yards, before I poop out (and I'm not in too bad shape). I'm fair at tennis and racquet ball.
However, in addition to being quite fit (30 push ups at 61 years old), I can do three sports things relatively well: pull back a strong long bow, throw a frisbee far and play golf relatively well (high 70s to mid 80s most days).
Last week at the Country Club of New Hampshire, on the par 5 8th hole, I got my second eagle in less than a year. Last year I bagged one at Woodstock Country Club's very short par 5 10th hole. Last week's eagle (a 3 on a par 5) was rewarding in that I hit a 260 yard drive, a 5 wood from 225 yards to 10 feet from the hole and sunk the putt.
Someone commented in Golf Digest about a year a go, that golf was one of the few "egalitarian" sports in that for a short time a so so golfer could outdo a champ. Maybe any of us could make a put that Tiger misses, or likely out do Phil Mickelson's 9 in the past US Open. Whereas few of us could survive even a few seconds with Roger Federer (Tennis) or an NBA basketball player.
But on the 8th hole last week, in my mind at least, a recovered Tiger, Phil and Adam Scott were in my foursome, they all got birdies and I got the lone eagle. Don't be mean.....let me dream!
PS: But my final score was an 80 and I'm sure the rest of my foursome described above would have shot around 65.
Cheers,
Dr. Ron
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Is REACH Going to Be RoHS Cubed?
July 28th, 2008
Folks,
Peg writes:
If the RoHS sweep does not scare you as a company, just wait for the REACH sweeps and SVHC list.
RoHS is the tip of the iceberg and paved the way for the much larger REACH program that will cost companies billions, put at risk companies IP.
REACH is being marketed at a greener way to test for substances and the goal is to combine all substances into one massive database so that we can “Share” in the knowledge of how substances effect our environment. However as this is generated so to is the SVHC (Substances of Very High Concern) that list those substances that the EU feels is not in the best interest of the environment (or better way to state it is the list that EU can apply a substance Tariff that will allow for the continued import.) Also a good way to get information on companies IP.
So be ready to have your checkbook ready, as it is free this year to register what it is you ship into the EU and at what tonnage you ship it. You can bet there will be a yearly bill sent to you and your company for the importing of that substance.
It is hard to not be sympathetic to Peg's concerns, where RoHS is only six pages and controls only 6 substances, REACH is over 800 pages and some suggest will cover up to 30,000 compounds. Here are some key REACH points:
- Its focus is for companies that export chemicals/materials to the EU, as opposed to electronics products.
- Companys that export more than 1 ton of materail to the EU need to pre-register the materials now. The deadline is November 30th.
- You will then be assgned to participate in Substance Information Exchange Forum (SIEF) in which you will exchange information with others and perhaps perfrom experiments to demonstrate the safety of a substance.
- Substances of Very High Concern (SVHC) will get the immediated attendion of the EU.
- If your vendors supply you with a chemical that you incorporate into one of your materials, they must pre-register their chemical, to assure that you can use it.
- Becasue of the mandated participation in SIEFs IP may be at risk.
All in all Yikes!
Cheers,
Dr. Ron -
Lead-Free Solder has Secondary or Less Impact on Tin Consumption
July 16th, 2008
Folks,
A few years ago, Prismark estimated that the world electronics usage of lead was 18,500 tons per year. Assume most solder at the time was tin-lead eutectic (63% tin, 37% solder) this would equate to about 50,000 tons per year of solder used in electronics and 31,500 tons of this solder being tin. With the advent of lead free soldering, using say SAC305 (96.5% tin, 3.0% silver and 0.5% copper), most folks would suggest that .965 x 50,000 = 48,250 tons of tin are now being used, an increase of about 17,000 tons of tin. However, solder is used by volume not weight, assuming a leaded and lead-free solder joint are of the same size (i.e. volume). Since the density of tin-lead eutectic solder is 8.4 g/cc and the density of SAC305 is 7.36 g/cc, a given lead-free solder joint weighs only 87.6% (100 x 7.38/8.4) of a tin-lead joint.
Considering this argument, our 50,000 tons of solder of solder per year, requires only 50,000 x 0.876 = 43,806 tons of SAC305 lead-free solder to make the same solder joint volume. This amount of SAC solder contains 42,276 tons of tin, an increase of less than 11,000 tons of tin over using tin-lead solder. When one considers that for wave soldering, the lack of wetting of lead-free solder further reduces the volume of solder used, the actual increase in tin usage may be < 10,000 tons.
The United States Geological Survey estimates that about 300,000 tons of tin are mined each year. So the increased use of tin for lead-free is about 3-4% of that mined. This figure matches well with the USGS’s statement that tin usage in the US rose 2% in 2007. However, with numbers this small it is hard to support any trend.
I thought these numbers might be helpful in understanding the impact of lead-free soldering on tin consumption. Many had assumed that lead-free would dramatically impact tin supplies, when in truth lead-free solder has only a secondary or tertiary impact on tin usage.
The photo is an image of a lead-free through-hole solder joint cross-section that my Indium colleagues took. It is likely that the equivalent tin-lead joint would have even more solder volume as discussed above.
Cheers,
Dr. Ron -
Meet My Fellow Indium Bloggers at Semicon West
July 8th, 2008
Folks,
Indium Corporation's industry leading semiconductor bloggers are hosting a
Meet the Bloggers session on Tuesday, July 15, 2008 at Indium Corporation's
Semicon West exhibit, booth #7834,
from 2-3pm PST.
The technology experts will lead discussions on topics including:
* Flux deposit measurement using non-contact metrology
* Two upcoming white papers (currently under development):
* Wafer Flux Spin-Coating Topography
* Wafer-Level Flux Printing
Recent hot semiconductor blog topics, including:
* Semiconductor assembly materials
* Future trends in first- and second-level assembly
* Halogen-free semiconductor assembly materials
* Engineered solders in MEMS assembly
* Thermal interface issues
* Solar device assembly
Indium personnel who will be discussing these topics include Jim Hisert, Paul Socha , Fez Sayed, Dr.
Andy Mackie, and Rick Short.
All attendees are welcome to participate in, or observe, the session. Snacks
will be served, too!
Indium's blogs can be seen at www.indium.com/blogs
Stop by and see them if you are at the show!
Cheers,
Dr. Ron -
IPC RoHS 2 Meeting in Brussels on June 18 Appears to Be a Good Start
July 7th, 2008
Folks,
In a posting , I recently mentioned that I was concerned that RoHS 2 seemed to be getting off on the wrong foot and that this was unlike what I felt were the conservative efforts by the EU in RoHS 1 . Most notably how the EU was not aggressively removing the exemptions for categories 8 and 9 in RoHS 1. Most troubling Re RoHS 2, was the exclusion of the IPC from an important stakeholders meeting.
In response, the IPC asked for a meeting with some of the EU RoHS folks to discuss their concerns. Industry leaders were also invited. A summary of the meeting can be found here. The meeting appeared to have accomplished a goal of developing a dialog between the IPC and its member stakeholders on one side and the EU Commission and the RoHS Technical Advisory Committee on the other.
The IPC will be writing a supply chain white paper on the possible effects of the RoHS 2 restrictions. This is the time for all of us "stakeholders" to encourage and support the IPC in this effort.
Cheers,
Dr. Ron -
Join Tim Jensen and Me at our Halogen Free Workshop at SMTAI at DisneyWorld in August
July 6th, 2008
Folks,
SMTAI is at DisneyWorld again this year from August 17-21. My wife and I are arriving early and bringing some of our grandkids for some fun at the Magic Kingdom etc.
Tim Jensen and I are teaching what we believe is the first ever workshop on halogen free assembly. Come and join us! You can register here . In addition to discussing the "how tos" of halogen free assembly, we will also discuss why it is happening.
Cheers,
Dr. Ron -
Join Me at ACI Wed June 25 for RoHS and Lead-Free Update
June 19th, 2008
Folks,
I am giving a 3.5 hour RoHS and Lead-Free Assembly Workshop at ACI in Philadelpia on Wed, June 25. Come and join me, it is free. The ACI facility is near the airport and is pictured above.
Cheers,
Dr. Ron
Want to read more? Browse the archive of past entries.
This Week’s Quiz
- Solve for X
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Folks,
I little math puzzle from my eye doctor:
x^x^x^x^x........... = 2, solve for x
That is: x raised to the power of x raised to the power of x........an infinite number of times = 2.
Cheers,
DR
Sideblog
Quick notes of interest:
- Dr. Ron's SMT Article "Repeal RoHS Movement Emerges" Causes Furor
Folks,
I guess I have stirred up a hornet's nest. My article Repeal RoHS Movement Emerges in the September issue of SMT and has generated much interest. I have even been accused of being the only person in manufacturing that is "pro-lead free solder." Wow! I think the folks at Motorola that have manufactured 150 million cellular phones, that could not be assembled with leaded solder, must have hurt feelings. Truth is I don't think I am "pro-lead free solder," I believe that I am pro data driven decision making....the topic for a future posting.
These articles have also caused much discussion on IPC's TechNet and I'm told a few other places.
Anyway check these articles out. I respect those that disagree with my perspective and believe that only by sharing and learning can we progress.
Cheers,
Dr. Ron
- Dartmouth and SMT Magazine Unite in Six Sigma Effort
"He is probably the most influential American you never heard of. The "Father of West Point," "Father of Technology in the United States" and the founder of Thayer Academy in his native Braintree, Mass., Sylvanus Thayer arguably left a greater mark on our country than half of our Presidents. Without him, there might not have been a Grant, Lee, Pershing, MacArthur, Eisenhower, Patton or many other great leaders. Most of the early significant engineering projects in our country were led by students of his, most notably the Panama Canal and George Goethals. One of the last things Thayer did in his long and productive life was to found and endow the Thayer School of Engineering at his Alma Mater, Dartmouth College."
See how it all converges on SMT and six-sigma at the SMT Magazine website.
- Articles in SMT Magazine
SMT Magazine is a leader in delivering sound technical information regarding electronics assembly materials, processes, and technologies. For a list of many of my contributions to this magazine, please follow this link.
- Lasky in Print
If you're interested in reading some of my publications, you can find many available here.
