Hi Chaz,
I concur with Pete. The key question is how much the development engineering
team is willing to take input from hardware compliance experts (both EMC and
safety). Does the team invite EMC & safety input early in the development from
concept to design (including design reviews), etc.? Are development engineers
checking on RoHS compliance for all components from the beginning as they
select components? Are alternatives (extra decoupling cap points and shielding
options worked into the design to be added as proved necessary in early trial
pre-testing? Is testing of early prototypes planned into the schedule to
confirm that the design is going the right direction? All of these are
indicators that the final qualification testing will go smoothly with no
surprises. In contrast, if hardware compliance only considered as an
afterthought with the dream that hardware compliance will just be a rubber
stamp acceptance of what they have done, the development team is likely heading
toward a rude awakening that could hugely impact the development schedule.
At an old company (not the one I work for today), the company experimented with
a budget process that allocated funds to individual development programs and
forced all outside teams (like EMC/Safety/RoHS, packaging, testing, sourcing,
etc.) to “contract” for funding in support of those development programs. Most
development programs recognized the importance of EMC/Safety/RoHS, but one disk
array development team decided that they did not need any EMC or safety
development design support and instead only “contracted” for the bare essential
final test and certification submission support. Of course, this was against
our advice, but they felt they knew better and could save some headcount cost
(spend their funds and headcount elsewhere). That disk array system had the
claim to fame of being 24dB over the emissions limit, and fixing the problems
caused redesign and anguish that delayed the product release by a year at great
cost to the program (many EMC design support hours and engineering redesign
hours).
That was the last year that this budgeting scheme was used, and senior
management made it clear to all development teams that EMC/safety/RoHS must be
involved early in the development process.
Hope this helps.
Monrad
From: Pete Perkins <00000061f3f32d0c-dmarc-requ...@listserv.ieee.org>
Sent: Monday, May 24, 2021 11:20 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [External] : Re: [PSES] What percentage of products pass first time?
Charles, et al, You question is rather simplistic, in my opinion.
From my more than 25 years doing safety & regulatory consulting
with dozens and dozens of companies both large and small, I find that the
experience of the design team is the key to meeting the requirements early on.
First timers (no prior experience having an outside lab test any
of their work for compliance) has a pretty low pass rate; no matter how much
advice is given during the design phase.
Design teams quickly gain experience ramp up & meet compliance
requirements on the next project or two providing the design is similar to
their earlier experience.
This level of competence can be confounded (made worse) if there
are substantial changes in the design team between projects. Newbies always
think they understand the needs and design accordingly; unless an experienced
team manager can ferret out the issue before testing and get them to change.
Additional features (especially radios) complicate the issue,
even for experienced design teams.
To specifically answer your question, first designs from an
inexperienced design team generally will need another pass (or more) thru the
lab to qualify. Experienced teams will have a high 1st time pass rate in most
cases.
To relate one scenario, a complex electronic research instrument
was developed by a 3 man team of PhD physicists who struggled when going thru
the EMC lab; they had no prior product certification experience. I had offered
to go to the lab with them but they thought they could handle it themselves.
They had no concept of the needs to provide the proper isolation between major
pieces (e.g. cables routinely pierced the chassis and made connexion well
within the equipment). After the 2nd failure the lab manager, a long-time
colleague, talked to me and said that they weren’t listening to his comments
about needed changes to fix it. Upon talking to them, they had dismissed him
as just a technician (ignoring his EE training and EMC lab experience) and they
believed that they knew better (but not good enough, as evidenced by the
continuing failure). So we had a ‘managerial discussion’ and I went to the EMC
lab with them from then on. The baling wire fixes tried at the lab showed
improvement when applied and led to installing proper connectors at the chassis
interfaces along with some other changes; it finally passed.
Others probably have more interesting cases to relate, too.
Does that fit with your experience?
:>) 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
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Entropy ain’t what it used to be
From: Grasso, Charles [Outlook]
<charles.gra...@dish.com<mailto:charles.gra...@dish.com>>
Sent: Monday, May 24, 2021 7:47 AM
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?
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