Monthly Archives: November 2011

Zzzzzzzap!!! Static be Bad

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Engineers these days have so many issues to worry about just in component handling alone:

  • Do my parts need baking to get the moisture out before reflow soldering?
  • Are my parts in stock?
  • Are my parts real or are they counterfeit or secretly remanufacturerd?
  • Are my parts really lead free?
  • Are my passive components small enough to make it out of the holes in my salt shaker so I can put them on the PCB?
  • Are my parts too small form my manufacturer to handle?
  • Are my parts too complex for my manufacturer to assemble?
  • Have my parts been zapped by static electricity either before or after assembly?

Static electricity is really something that no engineer should have to worry about these days. We know how it gets created. We know how to artificially create it and we know how to guard against it. There’s really no excuse – especially from those that an engineer entrusts to build his or her designs.

People can carry around a static charge anywhere from several thousand volts to more than 10,000V, just by walking around. Joe Volta would be proud. Touching an electronic component or assembly the wrong way at the wrong time can discharge much of that through the electronics. Yes, most chips are better able to handle static electricity than the old 4000 series CMOS that could get zapped just by being looked at harshly, but pretty much any active component is susceptible to static damage to some degree. What makes it so insidious is that the damage may be done in handling or in assembly but might not show up until the unit fails in the field.

The whole world knows how to keep electronics safe (that’s an exaggeration, but at least most people in the Industry know how), and the whole industry understands the risks, so why would anti-static handling or packaging be an extra cost option? If it’s you’re own stuff, then fine. It’s up to you. But someone you’re paying? I don’t get it.

Take a close look at the picture on the right. If you ever get a tour through Screaming Circuits, you’ll see a lot of this. The floor is conductive. The bright green straps on the shoes are not a fashion statement. They’re grounding straps. The blue jacket is conductive. Parts and PCBs are protected from static through these means and others all the way in and all the way back out to the customer. It’s the right thing to do and the healthy way to do it and it doesn’t cost extra. It shouldn’t cost extra. Follow good static mitigation procedures yourself and make sure that whomever is assembling your parts does the same. That’s my two cents worth.

Duane Benson
Frankenstein was grounded through his neck bolts, so he’s okay.

http://blog.screamingcircuits.com/

Reducing Conversion Costs

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Let’s look in on Patty …

Patty was just finishing a report on work that she and Pete had performed with a team of her ACME colleagues  on reducing the head-in-pillow (HIP) defect at a plant in Minnesota. HIP can be caused by printed circuit board or BGA warping during reflow, and, occasionally, poor wetting BGA solder balls. Fortunately, this case of HIP was due to just a little warping, so replacing the solder paste with one of the new formulations that was designed to minimize HIP had done the trick. Ten thousand boards were produced with no detectable HIP defects.

As Patty wrote the last sentence in the report, she gazed out the window at the dusting of snow that had fallen. She liked living in southern New Hampshire and was thrilled with the house that she and Rob had purchased six months ago in Exeter.  She had to admit that Phillips Exeter Academy was also a draw. She hoped her 18-month-old sons, Michael and Peter, would attend high school there, when the time came.

Patty was jarred from these thoughts by the ringing of her phone. She looked at the caller ID and saw that it was Mike Madigan, the CEO of all of ACME. Her stomach tied up in a knot. Sam, her boss, had alluded to the fact that senior management wanted to make her a VP. He asked if she had any requirements to accept such an offer. She said that she wanted to stay located where she was and she wanted Pete to be on her staff. Still, she was a bit nervous about such a big change.

“Patty Coleman, how may I help you?” Patty answered.

“Coleman, this is Mike Madigan. Congratulations, you are our new VP of Technology and Productivity. You will report to me, but, since you are staying in New Hampshire, I want you to report dotted line to Sam for day-to-day things. Coleman, don’t let me down. You are the youngest VP in the history of ACME by 5 years,” Madigan said.

Patty was a little put off by his gruff manner, but had been told to expect it.

“Thank you Mr. Madigan, I’ll do my best,” Patty responded.

“I already have an assignment for you,” Madigan continued. “You have done great things by improving line uptime at many of our sites, and profitability is up everywhere, but I sense we are still missing something. Do you know why?” he asked.

“Because the correlation between profitability and uptime is not as strong as one would like?” Patty asked.

“Coleman, I’m already glad I promoted you! That is exactly my concern. Explore the situation, fix it and give me a better metric. I want all sites to use this new metric so I will know which locations to focus on. I want a status report in three weeks,” Madigan finished.

“I’ll get right on it, Mr. Madigan, and will have an update in three weeks or sooner,” Patty answered, exhilarated, but a little shaky.

“Good! Oh, and Patty, call me Mike. It’s not the 1960s, you know,” he chuckled as he hung up.

Patty hung the phone up feeling happy and stressed. She was glad to get the promotion, but knew she had to deliver.

Patty had thought about this productivity metric concern in the past. She knew where to start, she would call The Professor. She was surprised when he picked up on the first ring.

“Patty, it’s great to hear from you. How are Rob and the boys? We expect to see your sons here at Ivy University as students in 16 years,” The Professor chuckled.

After exchanging a few more pleasantries and sharing the news about her promotion, Patty got right to the point.

“Professor, I need a metric that measures total productivity in electronics assembly. Uptime is a great metric, but it doesn’t correlate one-to-one to profitability,” Patty explained.

Patty expressed her surprise that no metric for total productivity was in wide use. They discussed the issue for a few more moments and then The Professor had a recommendation. “Read the NEMI (National Electronics Manufacturing Initiative) 1998 and the iNEMI 2011  Technology Roadmaps. Focus on board assembly and I think you will find your answer,” The Professor suggested.

After a few more pleasantries, The Professor had a request.

“Patty, I am getting a little award in Washington, DC. I have room for two guests at the award presentation. I was hoping you and Rob would come,” The Professor requested.

Patty said she would check their schedules, but was sure it would work out. She was honored that he thought so much of her and Rob.

As she hung up the phone, she went to ACME’s Tech Library in search of the iNEMI roadmaps. She quickly found the 1998 NEMI Technology Roadmap, but unfortunately only a summary of the 2011 iNEMI Roadmap was available. She thought she would read the 2011 Roadmap summary first. It was overwhelmingly impressive in its coverage of technology, at the wafer, chip, component, and board levels. The thoughtful inputs of over 575 participants, from over 310 organizations, were clearly evident. All of the current and emerging technologies were presented in detail.

“What a treasure of information,” Patty thought.

But she didn’t see an answer to her question.

So she went to the “Board Assembly” section of the 1998 Roadmap and in a few minutes she saw the answer: Board Assembly Conversion Cost in cents/I/O.

“What a simple concept,” she thought.

As she studied the document it became clear that about 30% of it focused on reducing conversion costs. Conversion costs were defined as all of the cost of assembly minus materials cost. To give this metric meaning, to enable comparisons between different manufacturing sites, the total amount of conversion cost for a manufacturing site was divided by the total number of input/output (I/O) terminals (i.e,. component leads) assembled.

“This makes sense,” she thought. “You add up all of the non-material costs of assembly and divide by all of the leads you assemble. This metric shows how efficiently you assemble each lead.”

It then dawned on her that she had seen a metric like this before. She saw the notebook from The Professor’s workshop on Cost Estimating in her bookcase.  She grabbed it and flipped through it. There it was: non-material assembly cost per I/O (NMACIO).

The great mystery to her was why the folks at NEMI didn’t emphasize these types of cost performance metrics in newer roadmaps.

Best Wishes,

Dr. Ron

Talking Data Transfer at ZDAC

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I had the great pleasure of attending Zuken’s ZDAC users group meeting earlier this month in San Antonio at the invitation of Steve Chidester, head of product marketing, and Amy Clements, marketing/sales manager.

Steve and Amy had asked me to present on electronics data transfer, a subject many readers know has long held my interest.

There were about 100 people who attended the event this year, slightly up over last year. All the usual Zuken folks were there: Gerhard Lipski, GM of Zuken Europe; Dave Gullickson, GM of Zuken USA; apps engineer Griff Derryberry; Humair Mandavia; Sandy Jones; and so on. I also was fortunate to meet with Zuken COO Jinya Katsube and CTO Kazuhiro Kariya.

As we’ve reported over at PCDanfF.com, just before ZDAC, Zuken rolled out two new tools: DesignForce, which accelerates prototyping by enabling chip-package-interconnect substrate optimization in a single, native 3D format. The CAD company also released CR-8000, its primary CAD flow. (DesignForce is embedded in CR-8000.) They spent a considerable amount of time discussing those two new tools and their ongoing product roadmap, including CR-5000 Lighting v. 14 next March, which will include a netless router. Zuken says it sees a need to move more information to upstream design, such as system and architecture. The main takeaway was that design makes up 4% of the cost of the process, but it determines 60% of the product cost.

I had about 45 people in my session. There was great interest in the topic, in part because some of the people there have been pushing their companies (RIM, Rockwell Collins, Northrop Grumman, to name but a few) to standardize on IPC-2581. All in all, it was well worth the time.

Also, Zuken is doing a lot in wiring harness design. This is a big market for many EMS companies (especially for military and aerospace work), and there are probably 12 to 15 companies that supply design software for wiring harness. (Some big ones are Mentor, Zuken, Eplan, Autodesk, and IGE-XAO). I didn’t attend the wiring harness design sessions, but it seems the audience was fairly split between the two.

Next year’s event will be held in Newport, CA, around the same time frame (early November).

QFN Stencil Gerber

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In the previous episode, Wally’s attack on Dilbert’s kingdom prompts Ratbert to perfect an “N”-Ray, to be discharged from a powerful Nullitrion, to neutralize and render useless Wally’s power plant. Dilbert tells Dogbert the Nullitrion can best be directed against Wally’s palace from the Devil’s Dome, in the Land of The Dead. Wally learns of their plans, and his soldiers plant a powerful time bomb on the Devil’s Dome, but are promptly captured by Pointy Haired Men. Dogbert and his party land, unaware of the bomb and the Pointy Haired Men who are watching and ….

As we rejoin our intrepid heros, you can see, circled in red, what the custom QFN stencil layer, from the previous episode, will look like in the Gerber file. Obviously the stencil cut outs will look like this too. Except they won’t be green. These format cut-outs will deposit the recommended 50 to 75% paste coverage in the center pad of the QFN leading to a good solid solder joint.

Stay tuned for next week’s episode, where Dogbert assists Dilbert in assaulting the manufacturing warehouse of Devil’s Dome to recover the missing 0402 bypass capacitors.

Duane Benson
Azura, Queen of Mars, ordered the Russian Phobos-Grunt probe to be disabled by a ray-beam

http://blog.screamingcircuits.com

Canadian Chemical Regulations: An View From Above

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Quality professionals focus on Europe, the US and even China — as with China REACH and China RoHS for example — when we speak of chemical regulations.  Sometimes we overlook Canada when we say “global.”

This is a mistake. Many supply chains go through Canada, and Canadian substance-level regulations are not shrinking violets at the regulatory compliance dance.

One really good way to stay on top of Canadian environmental law is to read the annual Blake’s Guide to Environmental Law in Canada. The document is an effective introduction to the principal laws and regulations in Canada and the provinces of British Columbia, Alberta, Quebec and Ontario, concerning environmental protection and conservation.

Specific advice should be sought in connection with particular matters or transactions — questions can be routed to the authors of this blog or to the environmental lawyers listed in the guide.

Key subjects include:

  1. Canadian Environmental Protection Act, 1999 (CEPA)
  2. Canadian Environmental Assessment Act (CEAA)
  3. Transportation of Dangerous Goods Act, 1992 (TDGA)
  4. Hazardous Products Act (HPA) and Canada Consumer Product Safety Act (CCPSA)
  5. Pest Control Products Act, 2002 (PCPA)
  6. Fisheries Act
  7. Canada Shipping Act
  8. Marine Liability Act
  9. Navigable Waters Protection Act (NWPA)
  10. Oceans Act
  11. Canada National Marine Conservation Areas Act
  12. Species at Risk Act (SARA)
  13. Migratory Birds Convention Act, 1994 (MBCA)
  14. Canada National Parks Act
  15. Criminal Law
  16. Energy Efficiency Act

The Canadian law firm Blake, Cassels & Graydon LLP has issued Blake’s Guide to Environmental Law in Canada.

The guide also provides an overview of environmental law in Ontario, Quebec, Alberta, and British Columbia.

Canadian law and toxic substances. CEPA, the Canadian EPA, provides the federal government with “cradle to grave” regulatory authority over substances considered toxic. CEPA provides for assessment of “new” substances not included on the Domestic Substances List, a national inventory of chemical and biotechnical substances.

It’s required that an importer or manufacturer must notify the federal government of a new substance before manufacture or importation can take place in Canada. Consequently, businesses must build in a sufficient lead-time for the introduction of new chemicals or biotechnology products into the Canadian marketplace. In certain circumstances, manufacturers and importers must also report new activities involving approved new substances so they can be re-evaluated.

All existing substances included on the Domestic Substances List are in the process of being
assessed by Environment Canada for bioaccumulation, persistence and inherent toxicity
(BPIT). Currently, Environment Canada is in the process of collecting information and
conducting risk assessments with respect to a series of “Batches” as part of the “Challenge to Industry” program.

Under the Canadian Environmental Protection Act, a substance is “toxic” if it is entering or may enter the environment in a quantity or concentration or under conditions that;

  1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity
  2. constitute or may constitute a danger to the environment on which life depends or
  3. constitute or may constitute a danger in Canada to human life or health

Substances that are persistent, bioaccumulative, and result primarily from human activity
must be placed on the Virtual Elimination List. Listed toxic substances include:

  1. PCBs
  2. CFCs
  3. chlorinated solvents

You can contact us or contact the Blakes, a law firm that regularly produces reports and special publications on Canadian legal developments. For further information about these reports and publications, please visit blakes.com.

TSCA Update: New Chemical Reporting for 2012

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Last week the US Environmental Protection Agency held a training session to further explain the amendments to the Toxic Substances Control Act (TSCA), scheduled for 3 hours this afternoon.  For those who couldn’t make it, here’s the distilled version:

For starters, there is a section 8(a) Inventory Update Reporting (IUR) rule change in name, to the Chemical Data Reporting (CDR) rule.  The new name is more precise, we appreciate that.   “Inventory” is a softer word than “chemical” but it has also far too broad an implication in the industrial world.

EPA is promulgating several amendments to the IUR / CDR rule, taking into consideration comments received on the proposed rule.  The amendments were proposed in the Federal Register issue of August 13, 2010.

In short, the way Production Volumes are reported will change:

*

Who is affected? Businesses are affected by this action if they manufacture (including manufacture as a byproduct or import) for commercial purposes chemical substances listed on the TSCA Inventory and produced in volumes of 25,000 lb or more during the principal reporting year (i.e., calendar year 2011).

Potentially affected entities likely include but are not limited to:

  1. Chemical substance manufacturers and importers (North American Industry Classification System (NAICS) code 325 and 324110; e.g., chemical substance manufacturing and processing and petroleum refineries)
  2. Chemical substance users and processors who may manufacture a byproduct chemical substance (NAICS codes 22, 322, 331, and 3344; e.g., utilities, paper manufacturing, primary metal manufacturing, and semiconductor and other electronic component manufacturing)

In short:  manufacturers — including importers — of TSCA Inventory-listed chemical substances with a 2011 production volume of 25,000 lb or greater at a site, unless otherwise exempted.

The 2012 submission period is Feb. 1 to June 30, 2012. You need to know:

  • Reporting is site-specific
  • Reporting standard is “known to or reasonably ascertainable by” for all data
  • CBI – upfront substantiation required for:
    • Site and chemical identity claims
    • Processing and use information claims [new requirement]

Manufacturing-related data includes:

  1. Chemical identity
    1. CAS RN and chemical name
    2. Accession number and generic chemical name for CBI substances
  2. Production volume (PV)
  3. Number of workers that are reasonably likely to be exposed (in ranges)
  4. Maximum concentration
  5. Indication of whether a manufactured chemical substance is being recycled, remanufactured, reprocessed or reused
  6. Physical form and percent production volume in the form
  7. Processing and use-related data are required for production volumes of 100,000 lb. or more, at a site, unless otherwise exempted

Online web based software can help with the new reporting requirements.  EPA has offered up a web based portal of similar nature.

*chart courtesy EPA CDR training info

 

Productronica: Still the Big Player on the Block

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Productronica, the trade show that’s so big, they can only hold it every other year, enters its final day today.

The PCB fabrication exhibits have shrunk over the years and are now down to about one hall (although exhibitors were spread over two, intermingled with large lounge areas and contract assemblers). Like the (much bigger) assembly sections, the exhibitors felt Tuesday’s traffic was slow, but Wednesday and Thursday were strong. While China may have spirited away most of the production, this is still the event outside of the Pacific Rim.

Take a look at PCD&F today; our recap of the fab hall is now up.

Major Major and Standard Standard

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We ask for your bill of materials, Gerber and centroid files to assemble your PCBs. All those pieces of information are necessary to properly program our machines to place your parts. That’s pretty standard stuff, but did you know that when the Gerber format reference book was first published, Jimmy Carter was President of the United States, Russia was the “Soviet Union” and Voyager 1 was well inside the Solar System?

Use of the format has been going on even longer. Yeah. It’s been around a while. For some reason, it has been very difficult to get everyone to agree to and use a standard file format. Gerbers really don’t have enough information in them to do the job properly, but it is the standard. Hopefully not for too much longer. How many of you reading this were even born when Gerber was new?

There are a number of formats around that are better than gerber and Screaming Circuits will accept many of them. First, your CAD software probably will export an “ASCII CAD file”. This is a good format. Some export ODB++, which is one of the newer formats, again a good choice. One of the newest standards is the IPC-2581. It’s been around a few years and is now getting a lot of attention. If you happen to use Eagle CAD, you can also send us the Eagle “.brd” file.

IPC-2581 includes the best of ODB++ and GenCAM. It has all of the fab data, assembly data, netlist and BOM. Everything needed in one convenient file. My understanding of the format is that you can exclude portions of the data set that you consider proprietary. You can learn more about the format here. There’s more background information on the subject at PCD&F magazine.

Duane Benson
Where’s Henry?
I need an inductor.

http://blog.screamingcircuits.com/

QFN Custom Stencil Layer in Eagle

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It’s been said over and over that you don’t want to leave the solder paste opening wide open for a QFN center pad. A 50 to 75% paste coverage will get the best results. With full coverage, your QFN can end up floating too high and not connecting with all of the pads due to their significantly smaller aperture.
But how do you create a custom paste layer? In Eagle, it’s not terribly obvious, but it is easy. Open the part that you want to customize in the Eagle Library editor. Open up the package for that component. Now, select “i” on the left side and click on the center pad. You might need to turn off the “tcream” layer in order to select the pad.

In the Properties dialog box, uncheck the check box for cream. That will get rid of the standard stencil layer. Now you can use the rectangle tool to add in stencil cut-outs as you want the. Make sure you set the layer for the rectangle to be “tcream” and remember that you are drawing the cut-outs of the stencil, not the blocked part.

Obviously it will be different for every CAD package, but the concept is the same. As is the need to do so.

Duane Benson
The Internet is weird.
There’s actually a website for paste eaters.

http://blog.screamingcircuits.com/

DEK’d Out

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Great chat with Michael Brianda, president of DEK, at Productronica. Some good insights on the state of the solar market, adding dispensing to the printer, and the franchising of stencil cutting.

Will have the full interview up later today.