Many thanks for your comments. They give me many ideas to conduct the meeting in the desired way. 

After reading the FED-18 document, I could imagine that there could be the problem you described. Something similar happened to me with Tantalum caps. In my opinion, the most interesting thing is to read how other people deal with similar problems you had. To see the same problem from another perspective. But any way, it is an interesting document.

Jami Smith had a compelling explanation (he sounded like a salesman) and Karen wanted to give the attendees an opportunity to vote on the subject. She forgot that 90% of the people in the conference meeting at APEX were not on the 1-13 committee. People just walked in to find out what was going on and they got a chance to vote on a very important issue. In hindsight, I could have swayed the vote by simply mentioning IPC-SM-782 but I didn't and the industry suffered a major bad decision. 

The FED Proportional Pad Stack feature was recently added to Footprint Expert, but we ran into a problem with calculating pad stack using percentages of package dimensions. Example: The 0805 chip component family has a dozen different heights and to calculate the Toe uses 40% of the package height. This would create 12 different footprints for the same Case Code. 

So we used the IPC J-STD-001 to calculate an acceptable Toe for a 0805 chip component. We then took every component family and every terminal lead and created Toe, Heel and Side goals that would be acceptable to meet J-STD-001 assembly. You can use Footprint Expert Nominal Calculation Mode but you need knowledge of solder joint goals. We did a good job at creating the default solder joint goal values, but they are intended to be adjusted by the end user. 

When you download hundreds of thousands of component datasheets and compare the manufacturer recommended pattern to the Nominal Calculation Mode, you realize the manufacturers do not use Min/Max calculations. They use Nominal Package Dimensions and apply a Toe, Heel and Side (just like the FED Volume 18 concept). Component manufactures don't use the tolerances they publish in their datasheets for their recommended pad stack pattern. 

The IPC-7352 uses Min/Max Calculation Mode which is dependent on the mfr. package tolerances to form the solder joint goals. The major flaw in the Min/Max technology is that component manufacturer tolerances are too robust or not truly accurate and sometimes just composed and unrealistic. The CAD Librarian must be familiar with package tolerances and spot bad tolerance data in the mfr. datasheets. 

Example: for years SOIC manufacturers had an 'L' tolerance of 0.41 mm X 1.27 mm. This tolerance is way too robust and not realistic for today's machine technology. This tolerance makes the pad length way too big. A CAD Librarian would have to know what a good nominal dimension is and a reasonable tolerance. Same concept applies to every component family and terminal lead in the electronics industry. Use reasonable tolerances. 

BTW: it looks as though component manufacturers are finally realizing that their package and terminal tolerances impact the pad stack calculation and they are reducing their tolerances to be closer to reality. It took us long enough to get the component manufacturers to use standard package dimension characters and standard component family name references. It was out of control 20 years ago. 

All the best to the CAD librarians around the world who have to make these decisions everyday. I wish all of you good luck in making the best informed choices for your CAD library.

Many thanks for the explanation, for letting know us why IPC-7351C never existed. I remember that we waited for long for the new "C" version and at the end it was named   IPC-7352 and it was downgraded to a "guideline".

Do you think the IPC will recover in the future the "spirit" of the IPC-SM-782 about pin1 orientation? Perhaps so many time doing the things without knowing "why" in that way, that someone will want to standardize it with any reason...

After reading your grate explanation about what happened, I have a question about it: Why Ms. K.McConnell accepted the explanation of Mr. J.Smith?

Thanks to PCBFE I read a very interesting article from Mr. Rainer Taube about "New Proportional Land Dimmension" and after that I read the full article in FED-18, do you think this new concept will be more visible in a close future?

I joined the 1-13 IPC Land Pattern Committee in 1999 to help Dieter Bergman with a IPC-SM-782 software calculator to replace the IPC on-line land pattern calculator that was very expensive for IPC to maintain. 

My first goal was in 2000 to transition from using imperial units to designing PCB library parts and PCB layout using the metric measurement system. The first calculator Jeff and I created was an Excel spreadsheet with called LandCalc. It was primarily SMD and only supported metric units. This was to run all tests to ensure the IPC mathematical model for min/max calculations was perfect. 

The first calculators only had one rotation 'Pin 1 Lower Left' which was what the IPC-SM-782 supported since March 1987. After all, it was just an Excel spreadsheet and we didn't have the luxury of multiple rotations.

It took 2 years to add all the component families and finalize the min/max mathematical model. Then thanks to Philip Restall in the UK, we added a CAD tool translator for Mentor Graphics PADS. PADS was ASCII format so it was easy to figure out and we renamed the Excel spreadsheet to LandWiz. We freely distributed LandWiz on a website www.pcbstandards.com and had lots of downloads. 

Then in 2003 we started writing code for the first software program which was Land Pattern Wizard. We shortened the name to LP Wizard. It was unique because there was only one footprint rotation 'Pin 1 Lower Left' because user feedback wanted us to fully dimension the resulting footprint to make it easy to QC. 

Then IEC introduced the 3-Teir PCB library solution and we had to change everything to add the Least, Nominal and Most solder joint goals. This took another year to implement into the software tool. 

We completed LP Wizard in 2004 with 3-Teirs, lower left was the zero component orientation and metric units only. We delivered it to IPC to test and replace their on-line calculator. 

IPC was interested in getting volunteers involved in the approval process and were signing up volunteers quickly. We invited industry experts in join the IPC committee. Unfortunately, many of the volunteers turned out to be takers rather than givers. They attended meetings get information rather than provide information. 

IPC had the final 1-13 Land Pattern Committee meeting at the 2004 IPC APEX conference in Anaheim, CA. We invited everyone in the local area to attend, especially members of local IPC Designer Council members. I spoke at the local San Diego chapter meetings regarding this new technology and try to convince everyone to transition to the metric measurement system. One attendee at the meeting was Jami Smith. He liked to attend IPC Designer Council meetings to learn more about standards in the electronics industry. Jami said he was interested in helping with the new land pattern committee, but the committee had already completed their goal of upgrading IPC-SM-782 to IPC-7351. But there was one more meeting at IPC APEX in Anaheim, CA and Jami Smith attended the meeting. He was about 30 minutes late getting to the meeting and when he entered, he recognized me and sat next to me. I was running the projector through my lap top showing the committee the new LP Wizard software program and the IPC-7351 draft. 

80% of the attendees at his final meeting were newbies who never attended a single Land Pattern meeting. They were just people who wanted to learn more about the new standard. Also, this was the first and last IPC Land Pattern Committee meeting that Jami Smith attended. We were all set to finalize the standard when Jami stood up to address the attendees. He claimed to have knowledge of EIA-481 and insisted that the EIA zero component orientation for pick and place machines was Pin 1 'Upper Left'. No one at the APEX meeting knew anything about EIA-481 so they took Jami's word that he was trying to contribute information that we were unaware of. 

Vern Solberg was one of the committee leaders and he suggested a committee vote from everyone in the room. Don't forget that 80% of the attendees had never attended a standards meeting before and they were asked to vote on an important subject. Karen McConnell the committee chairman was there and she agreed with Jami Smith. Then when everyone voted, they sided with Karen and Jami and that was the turning point for the IPC-7351 Zero Component Orientation. Jami Smith left the meeting and no one ever saw him again. But the damage was done. 

It took us 3 - 4 months to change all the footprint rotations in LP Wizard. IPC-7351 was released in 2005. IEC got involved and chastised IPC for changing the footprint rotation based on faulty information and a rash decision at a meeting that no one had the knowledge of what impact they had on the entire electronics industry. So IEC released the IEC 61188-7 which reverted back to IPC-SM-782 zero component orientation. 

Dieter Bergman and I had a conversation in 2008 about changing the zero component orientation for IPC-7351B, but Dieter said that once a standard is released it's very difficult to say you were wrong and here's the correction. Dieter shrugged his shoulders and said "Let the best standard win". However, in 2014 the IEC standard was winning and Dieter agreed to change the zero component orientation in the new IPC-7351C. We had the kick-off meeting at IPC headquarters the week of July 15 - 19. We created the entire framework for the new totally upgraded IPC-7351 standard. I left the meeting and flew back to San Diego, CA and immediately started working that weekend on Chapters 5 for surface mount and 6 for through-hole. The following week on July 23, Dieter Bergman passed away. This was a devasting loss to the electronics industry but I was inspired to carry the torch and spent the next year writing the IPC-7351C with Rainer Taube in Germany. We introduced IPC-7351C to the Land Pattern Committee in 2016 and we worked on refining it for 6 years. Then we found out that Dieter never had the approval by the IPC executive committee for IPC-7351C and they shelved it, never to be released. 

Bottom line is that the Pin 1 in the upper left for xero component orientation should have never been released and Jami Smith will go down in history for changing a standard that he had no business being involved in. Jami disappeared never to be heard from or seen again.

And now you know - the rest of the story...

Dear Nick and Team,

In our company, there is a great discussion about the pin1 orientation. To use IPC-7351 or to use IEC-61188-7. 

I've read the article of the Top, and at the end my conclusions are:

- IEC-61188-7, is and standard very extended in Europe and some countries in ASIA that over the years has been consistent, has not changed. In other hand IPC-7351 modified the criteria from IPC-SM-781.

- IEC-61188-7, is more close to the IEC-481 from the point of view of the pin1 on reel.

- JEDEC has pin1 in cuadrant 1.

Is there anything else that I missed that I could argue to convince to my colleagues to use IEC-61188-7?

That's true that PCBFE gives us the possibility to configure it, but we would like to use the  same  .opt file on each site of the company.

Thanks for your comments.

david

The Top Side footprints rotate counterclockwise. 

It could be different for each CAD tool.