Our repair techs weren't that good. The idea wasn't to hire expensive help.
Never a problem. If there's a question, get the BOM. It's on the computer right next to their bench. They have the database open anyhow.
EEs in QC? Shirley you jest!
in
P/Ns
It certainly happened.
the
Re-enter what changes? It's a new board.
Obviously. To err... The idea of the release system is to make those errors difficult to get through to the product. In an ideal world, catch them all before a dime is spent.
It sure made sense to management when these errors went to zero.
I fully disagree, because the system I described has worked for me for
25 years and counting. Not one boo-boo that whole time, and as a consultant I do get around. If a company can't get their hands around it that does not mean a system is bad.
In medical ultrasound and similar cases boards are very large and complicated. Your "Dude, look it up in the BOM" method is not going to work there and we don't put techs through that sort of ordeal.
I have lots of designs that are heading for their 20th birthday.
Because you guys must have dunnit wrong with that process :-)
I am doing a schematic right now that has both thermal pad and shield can. Both are shown on the schematic. The thermal pad is only shown for illustration though because that is part of the library model. Reason I show it is because I provided a hole where the tech can reach through with a Weller tip if in need. So they know there's a hole underneath without having to read that part of the module spec.
So far I've been able to prepare my tax stuff sans schematic but the way the complexity of tax law goes there may come a day when that's no longer possible.
*don't*
Not
Then you guys did it wrong. None of the schematic where I ever took part in was an uncontrolled document. Besides agency audits my clients often have inhouse audit teams that work the same ways as the agency guys. That way we make sure it's all legit.
While being a manager I always received a copy of theri report. We did pretty good, the highest offenses were usually things like a cart sticking out 5" beyond the yellow line.
No, ours never went wrong.
your
In medical devices you would have issues. So my suggestion to your company would be not to do that.
board.
If something hits the fan and a lawsuit is pending the investigation works in part very similar to what agency guys do with my clients. So if, for example, a tech in the witness stand caves in and admits to having used a hand-marked schematic at the board repair station -> "No further questions, your honor".
was
You'd have needed a consultant to show you how to handle that kind of system :-)
No joke. This is why when we shopped for a bigger corporate doc system we made it a requirement that the vendor have med devices exposure, and wanted references to that effect.
"live"
the
absolutely
valid
So how is the BOM correctness level higher than the netlist correctness?
A schematic is nothing more than the graphics rendering of a netlist.
Not needed. They are allowed to write down a phone number et cetera, or a sticky pad "Meet Lucy for lunch". But they are not allowed to write onto controlled production documents. In my line of work a set of schematics is such a document. They are also not allowed to make documents that are clandestinely used in the process. For example, a sticky note saying "Turn L5 to 8.2MHz instead of 7.9MHz and correct that later". Big no-no because that would be like having a bong on the dashboard when highway patrol pulls it over.
Don't
To some extent that is true and can be seen in situations where "seniority rules" exist. We could fire them, and sometimes had to. But not very often at all.
Ok, if they couldn't read schematics anyway that explains your reluctance here. We needed top-notch guys because most med gear is rather complex and requires techs to have a basic understanding of how amplifiers, uCs, logic chips and such work. Many of our techs had associates degrees. We also fostered (via hefty financial aid) a path to a bachelors degree so they got a chance to move into engineering. That was a major morale booster, one of the best things we ever decided.
another
How can QC do their job, a.k.a. quality control, if they do not understand the innars of your products? You guys really seem to be flying seat of the pants here :-)
In fact, the VP of QC asked me to personally interview his short list of candidates when he hired an EE.
in
a
P/Ns
As I said, then folks in your company must have violated procedure. I have never seen it happen. 25 years and counting.
the
to
If you change R92 from 12.1k to 14.3k plus some other changes like that this does _not_ require a new PCB.
in.
That is why we, for example, have rigid netlist checks. Even back in
1986 when DOS was ruling the world it was a piece of cake to have the computer do a 1:1 file compare. So if someone screwed up in the rev C schematic edits the warning would pop up right there on the old green CRT. Because it as manadatory that it had to match the netlist from rev A since that's what the board layout was based upon.
We also did them by hand back then but never caught the computer to err.
... and they missed out on the best solution they could have had. Big time. If they don't read this thread they may never know :-)
up
the
So you never repair anything? Sounds rather eco-unfriendly and wasteful in terms of gross margins.
That's what Atomic Energy of Canada thought, too. Until their Therac-25 therapy system severely hurt lots of people and killed three of them. This is one of the reasons why agencies have stepped up the requirements placed on medical device companies.
But if your stuff can't hurt or kill people it may be ok not to follow such procedures.
These rules are not nonsense at all. They are very similar to numerous other fields such as aerospace, and they save lives. Since I grew up in med devices I have no problem getting used to strict rules in other markets, it's not much different from being transferred to another job in the military. When I did my first aerospace electronics design and submitted it I didn't hear feedback. So I asked whether the documentation was ok. "Yeah, it's all in there. We never see that with new consultants, where did you learn that?"
They can read schematics, alright. Calculate what voltage should be, not so much. At least one had an associates. Not sure about other but he'd have a better chance of figuring out such things (and old-school tech).
another
Nope. They look for process problems and "are all the parts on there". They wouldn't know a schematic from flypaper.
For QC? What a *boring* waste of an EE.
look in
like a
P/Ns
No, they made mistakes and your process wasn't there to help. The changes we made did.
build the
to
You did say "Painstakingly enter all changes into the old schematic". That doesn't happen, *intentionally* on a BOM-only ECO.
Then they would not be able to use a scheamtic to any useful potential, at least not often.
another
Impossible in medical devices. A QC department that does understand how our products work would have been no good to us.
I could not have done that job for too long either. Once a QC EE and I had to drive to the Bay Area to audit a company (yes, sometimes I am Inspecteur Clousieau ...). Meaning almost 6h in the car, lots of time to talk. He actually liked his job a lot. It also paid quite well because it comes with a lot of responsibility.
look in
like a
P/Ns
Sorry, I disagree. If they had really followed the process the mistakes would have been caught. But you pointed out one major problem yourself: You guys have no EEs in QC. So I guess nobody is double-cheking what your EEs do. Not good at all, IMHO.
build the
enough to
We just issue a new schematic, new rev level, _correct_ and _actual_ values in there. That's the proper way to do it. BOM-only ECOs are horrid.
Of course they can. Even with *no* values shown schematics show the circuit topology very well. In fact, when we sent schematics to UL, et. al., all values were stripped from them. They were happy with that.
another
Why? Is QC's job to check your work?
...and no other sucker would take the crap job. What a waste.
look in
like a
the P/Ns
You disagree that they helped? Fortunately, management trumps Usenet peanut gallery opinions. ;-) Of course there is no one looking over the shoulder of EEs. While they haven't exactly treated as adults, recently, they were responsible for the design. No dope that couldn't find any other job was looking over their shoulder.
The only documents that can be trusted are the ones that are formally released. Even if they are wrong, the things that are wrong can be formally corrected. Anything else is chaos.
If you only make a couple of products, and are personally, intimately familiar with each one, you can get by with informal documentation... for a while. But that doesn't scale. Once you have hundreds and thousands of schematics and assemblies and revs and BOMs and datasheets and manuals and test sets and test procedures and firmware versions and FPGA versions, you need formal control.
Don't try that with a primary switcher on a med device, or with a unit for RTCA/DO-160 aircraft approval, they'll throw it right back at ya. It's sorta important whether the resistor across the barrier is 50M or
50k and they won't be bothered with having to measure all those.
another
Yes, in med it most certainly is. That is why one of their EEs sat in our design reviews, always. And they did ask questions.
So you also think that aerospace engineers whose sole job is checking aircraft structural integrity and design, engineers who do crash tests on cars for a living, engineers who check the integrity of bridges and so on are "a waste"? Maybe some folks thought so in Minnesota, and people died. Or on the Therac-25 therapy units, and people died.
Sorry, I fully disagree with you on this one.
look in
like a
the P/Ns
Read again. I said I disagree that the change away from a system like I described was unnecessary, an IMHO a mistake. But I do not care what your management or you think about it, it is not my company. As long as you don't build medical stuff, aircraft or anything that can hurt or kill people.
never
as
build the
enough to
And that of regulators. Which is what really counts for me.
As I said before, then I wish you guys good luck that there will never be a situation where something burns down a big building or someone gets hurt. Because then chances are that the DA, the jury and the judge see it the same way I see it, which is the same way government agencies see it.
computer
reference
another
They
That assertion is IMHO wrong. Unfortunately they design houses that way in some countries and we've all seen the grief that has caused.
Take a look at your ECOs. Does QC sign off on those or not? If they don't, then you guys are really flying seat of the pants. Probably nothing wrong with that in your opinion. As long as nothing bad happens, that is ...
Second that. Somebody has to design and build life-critical stuff, but I don't want to. I can probably design five times as many new things per year if I don't have to conform to *anybody's* standards. And since designing new things is what I like to do, I avoid standards.
A lot of our products are risky and speculative. We push parts, push performance, make a couple, and put them on the web site, or loan protos to customers, and see what happens. We don't need no stinkin' marketing department! We couldn't do that in a regulated environment.
A couple of our OEM customers do take our stuff through CE and UL as part of their systems, and we make any changes they require, but the hasslefactor is low there.
computer
reference
another
They
Ditto here. QC makes sure the products are built to the drawings and are assembled and soldered to high quality levels. We do invite our test manager to design reviews, where she comments on testability issues and often helps in the overall review. Our production manager is also our primary mechanical designer, so he's invited to any design sessions and reviews if there are any new packaging or cooling or assembly issues. The Brat has a checklist that she makes sure is run through before we release anything. A PCB will get at least two group reviews, one when the first schematic is sort of roughly done (lots of debate in that one!) and one just before release, after the board is laid out, the BOMs done, all that.
I've had no problems with CE/UL/CSA. As long as the product is well designed there's usually little to nothing that needs changing.
Once you start to deal extensively with a heavily regulated field it pretty much seems to make you uncompetitive in fast-moving commercial or speculative R&D products. Salaries are usually much higher, schedules can be an order of magnitude longer, nothing happens without firm specifications, and all that sort of thing. Unless you're big enough to hive off a division that can be hermetically sealed off from your other business it's a one-way street. It may be fine for a consultant, but it can easily be fatal for a smaller company that has to finance themselves over the very long lead times before revenue starts to appear.
Best regards, Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Actually, it can be done by a smaller company. We've done it. This stuff would not exist otherwise and many people would die if it didn't:
formatting link
Very strictly controlled by agencies because the ultrasound catheter that connects to it goes _into_ the heart of people. I personally brought the original system through safety cert for the patient side when it was still under our name (EndoSonics), mainly because I had designed the patient interface. This company was later successfully sold. The company that bought us messed it up. It seems not everyone is able to run a medical electronics manufacturer. Now it's all back in good hands again.
Fussing about onerous rules and regs is easy to do but somebody has to design and build this kind of stuff. Because most of us will becomes seriously ill at some point and then we need it to be there.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.