Having been in the EMC business now for going on 40+years, I concur with what Pete is saying. The truth of the matter is, this field of study is sadly under taught and is still more hands on and learning by trial and error for the most part. Yes, there are a lot of good ‘classes’ you can take, but the fact remains, this is more than not an OJT field.
As to manufacturers designing at the limit. This is also true, and also problematic as it means far too many products still fail first time out. I don’t know if I would necessarily agree with the percentages reported, but it is getting a better. My last 20+ years has been working in the regulatory approvals end and I can say that failure to comply with rules and standards is still a big issue with manufacturers. Thanks [cid:image001.png@01D75167.18F10910] Dennis Ward Senior Reviewing Engineer PCTEST Engineering Laboratory, LLC. 7185 Oakland Mills Road Columbia, MD 21045 1 410 290 6652) dennis.w...@pctest.com<mailto:dennis.w...@pctest.com> | www.pctest.com<http://www.pctest.com/> | www.element.com<http://www.element.com/> This communication and any attachment contain information from PCTEST Engineering Laboratory, LLC. and is intended for the exclusive use of the recipient(s) named above. From: Pete Perkins <00000061f3f32d0c-dmarc-requ...@listserv.ieee.org> Sent: Tuesday, May 25, 2021 12:39 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] What percentage of products pass first time? CAUTION:This email originated from outside of Element Materials Technology. DO NOT click links or open attachments unless you recognize the sender and know the content is safe. Please contact IT Service Desk if you are in any doubt about this email. James, You don’t have to denigrate yourself as not being a guru. You have plenty of experience in this as shown by your comments. Sharing this is quite valuable to the others on this thread. All of us started out as ignorant of any of these requirements because they are not taught in formal college level courses; a few exceptions seem to exist. Some folks might get specialized training – if they work for a gov’t agency or a safety test organization; else it’s all OJT. I don’t see that changing any time soon; the academic folks have their interests which continue to push mathematical analysis techniques (and that will continue). More and more technical folks will get higher degrees [you know what BS is, MS is More of the Same and PhD is Piled higher and Deeper :>) ], hardly any of which is of interest at our daily working level. Manufacturers will continue to steal trained folks from test labs; probably not too bad a deal especially if the folks move back and forth to spread what they’ve learned going each way. Finally, the standards keep getting more complex (PhD effect) and interrelated as issues are delved into more deeply; plus manufacturers are getting better trained to design near the limit without as much margin so the compliance is close to falling off of the edge of the world at any moment. So keep at what you are doing as long as you enjoy it; then get out gracefully – keeping your reputation intact to maintain a legacy as you go. Enough of Phil 101 today. :>) br, Pete Peter E Perkins, PE Principal Product Safety & Regulatory Affairs Consultant PO Box 1067 Albany, ORe 97321-0413 503/452-1201 IEEE Life Fellow IEEE PSES 2020 Distinguished Lecturer www.researchgate.net<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.researchgate.net%2FPeter%2520Perkins&data=04%7C01%7Cdennis.ward%40pctest.com%7Cf10796d676544029a29a08d91fb4b724%7C048204512a274c35a1d499fa8eb67e80%7C0%7C0%7C637575683315196024%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=vMP7NQX0RVdQw7XX7mD2zN56lfu9cAx6HgLOGauUJ2A%3D&reserved=0> search my name p.perk...@ieee.org<mailto:p.perk...@ieee.org> Entropy ain’t what it used to be From: James Pawson (U3C) <ja...@unit3compliance.co.uk<mailto:ja...@unit3compliance.co.uk>> Sent: Tuesday, May 25, 2021 1:19 AM To: EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] What percentage of products pass first time? (replying even though I’m not a guru) Hi Charles, hope all is well with you Speaking from my own experience. Over the last four years of running a consultancy, pre-compliance and low cost test EMC laboratory I would (very roughly) estimate that around: * 50% of products pass their desired radiated emissions limits without any modification * 33% or less pass all of the applicable tests first time without modification The major caveats and notes here are that * These figures are for customers products where the EMC performance is not known before testing. We do a lot of work helping people solve existing EMC problems but we are not counting this in these figures. * Most of my customers are smaller businesses that can’t afford to employ an engineer to just look after compliance. That job role is either split amongst several people or the engineer in question has to look after quality, manufacturing, sustaining, thermal, system, and everything else. Speaking as someone who has designed many products and systems in the past, trying to design for functionality whilst simultaneously considering best EMC performance is HARD. I use the metaphor of * The products that pass first time generally fall into one of three categories * Products that we have design reviewed before the design was finalised * Retests of products that have already been through our lab once * Products that are very simple in nature * Our hit-rate at being able to solve our customers problems is around 90-95% * The “ones that got away” where we were unable to help deliver a compliant include * No action taken: Products where it was deemed by the manufacturer not economically feasible to modify the product (e.g. product going end of life) * No further communications from the manufacturer so we don’t get to find out what happened next (no news is good news, right?) I would echo the sentiments of others on this thread regarding the need to design in compliance from the start. One of the problems with the field of compliance is that it is too often “learned through experience in industry” and not explicitly taught. When it is taught at academic level it is often a surface treatment with a theoretical look at shielding or maybe crosstalk with no other practical context or background. The split between industry and academia is one of the possible causes. Yes, there are exceptions to this but they primarily remain exceptions. I had discussions with a local university about some guest lectures on compliance and the theme of the response was “it doesn’t really fit into any of our modules” and “we can’t have it as an optional lecture as none of the students will attend”. The number of times I hear “oh, thanks for that. No one has every explained it that clearly before” is worrying! All the best James James Pawson The EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental : Safety : CE + UKCA : Consultancy www.unit3compliance.co.uk<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.unit3compliance.co.uk%2F&data=04%7C01%7Cdennis.ward%40pctest.com%7Cf10796d676544029a29a08d91fb4b724%7C048204512a274c35a1d499fa8eb67e80%7C0%7C0%7C637575683315196024%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=F9GDgetAYgs%2FmX4%2BSGBsOgIz%2BJL%2B7mNxhlCZNXjCdeE%3D&reserved=0> | +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 From: Grasso, Charles [Outlook] <charles.gra...@dish.com<mailto:charles.gra...@dish.com>> Sent: 24 May 2021 15:47 To: EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] What percentage of products pass first time? Hello EMC gurus! Calling all labs - In your experience how many products pass the Unintentional Emissions test first time? - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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