I don't think I want to run a foreign EXE file. What does it do?
My little program looks for ratios using parts that we already stock.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
In this case you need some sort of indirection. Some products may care which transistor is used. You can't then put the parts in the same bin.
We have to opposite problem. We have at least ten 1K 1% 0402 resistors in the library. They can't be interchanged. When one is selected for the board, unless there is some sort of failure, it'll last the life of the product.
At a PPoE, resistors could be swapped by production/purchasing but any capacitor substitution had to have engineering approval.
Exactly. That's why we can't even change resistor manufacturer (without a complete test cycle).
Calculates parallel and ratios based on the standard tolerances.
Yes, I forgot that you mentioned that earlier. ResCAD won't do that, of course, so it would not be suitable for you. Sorry.
ing. When perfectly practical I design circuits to work on a range of trans istors, particularly for jellybean jobs. I can see no reason to restrict tr s, in many cases, to just one type.
redirection? If that's how your system works.
I hope no-one would, though there might be a general purpose jellybean bin in some companies.
NT
If you like that word better. The part number is a pointer to a list of pointers; to me, indirection.
Our system? No, no such thing allowed. There is a forced 1:1 correlation between corporate P/N and supplier P/N, right down to the size of the reel the parts come on.
That's just one more part number that has to be stocked. Unless there is some means to raid multiple bins to get an acceptable part, I don't see the purpose.
Are multiple suppliers allowed for one part? We can put any qualified
1K 0805 1% resistor in the 132-5001 bin, and that stock number 132-5001 is what's on the BOM. Engineering can authorize purchasing to add a vendor+vpn as needed.Sounds like the answer is "no." So what do you do when you want to use a different mfr for a resistor?
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
No. As I mentioned in an earlier post, we probably (forgot to count today) have ten 0402 1K 1% resistors. They're all different part numbers and cannot be interchanged.
At a PPoE, manufacturing was allowed to buy resistors based on specification but had to have engineering approval to substitute capacitors. There was an "Engineering Substitutions Only" checkbox in the Agile database.
If *I* want to? I specify that resistor on the BOM. Forevermore, that part gets used in the assembly. Manufacturing is not allowed to change anything. Any deviation (part not available) would trigger a complete verification cycle, which takes months.
limiting. When perfectly practical I design circuits to work on a range of transistors, particularly for jellybean jobs. I can see no reason to restri ct trs, in many cases, to just one type.
Sounds like a good example of how what is required for one company is inapp ropriate for another. These days I work at the other end of the scale, and such measures would make no sense here. I don't miss mil spec work one bit.
NT
That's generally reasonable, I think, and it's pretty much how I design things. (One exception is thick vs thin film, which matters a lot in front ends.) There are a whole lot more things to go wrong in capacitors: tempco, voltage coefficient, polarity, lifetime in hot environments, possible detonation. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
In our shop, only engineering can authorize a manufacturer/MPN to go into a stock bin. But a bin can have up to five authorized sources.
Sounds awful. A BOM specifies a Vishay part number for a resistor, on a 3K reel, and you have to revise the BOM if someone wants to buy a 1K reel?
Reverification (which sounds scary to me) is required if you change anything? Months?
We deliberately no-bid anything that requires part traceability or gigantic amounts of testing. Life's too short (and engineers too expensive) to waste on mountains of paperwork.
There is a pragmatic compromise here: massive controls will maybe reduce the background bug/error rate (or maybe not!) but are not worth it in the long run. Some time back it was discovered that gumdrop plastic transistors were more reliable than hermetic, documented, burned-in JAN/TX parts.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Yes, but it's not by choice. It's not mil spec, likely worse. It all goes to the cost of doing business.
Same thing, sorta. I think the difference is that their purchasing department could do the substitutions without input from engineering, as long as the checkbox wasn't checked when the part was released. From what I know of your company, the two were of comparable size which makes a difference.
Not that bad. They don't buy form distributor stock (though often disties are middle men). There are long-term sourcing agreements in place so the manufacturer knows what size reel to make. It's a high-volume business so manufacturers will make sure they can supply the requirements.
Months. The customer gets involved, too.
Mountains. I've never been to the production facility but they most certainly wand every reel into the line for lot traceability. Again, CoDB.
I don't think the issue is reliability, rather blame. ;-) They want to know if there is a component causing a production bust, whether it's a lot or systemic, and how to fix it (and who gets the bill).
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appropriate for another. These days I work at the other end of the scale, a nd such measures would make no sense here. I don't miss mil spec work one b it.
It's all extra services you charge a profit on. If your customer demands it , it's worth it in that sense. The trouble is you become more a paperwork c ompany, what you do changes, and the job of successful electronics takes ev er lower priority as it gets messed about by a heavy dose of genuine issues , trivia, irrelevance bs mixed together. I used to find it frustrating.
NT
That would be all fine and dandy were there not competitors. It's a cost of doing business, though it does tend to reduce competition from upstarts wanting a piece of the business.
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inappropriate for another. These days I work at the other end of the scale , and such measures would make no sense here. I don't miss mil spec work on e bit.
it, it's worth it in that sense. The trouble is you become more a paperwor k company, what you do changes, and the job of successful electronics takes ever lower priority as it gets messed about by a heavy dose of genuine iss ues, trivia, irrelevance bs mixed together. I used to find it frustrating.
It's a cost of business all manufacturers in that area pay for, and all pas s it on to the customer. Thus the customer gets whatever extra requirements they want - almost - but they pay for it all plus profit.
Some of these extra requirements are worth it, some aren't, some are counte rproductive. But the customer's paying.
NT
It's all how you look at it. The one who can more efficiently cut cost of compliance or is willing to sacrifice the "additional profit" off the paperwork gets the contract.
Right. Some are and some aren't. The difference isn't always so easy to see, though. The only such tracking needed is for failing parts. If they don't fail...
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is inappropriate for another. These days I work at the other end of the sc ale, and such measures would make no sense here. I don't miss mil spec work one bit.
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nds it, it's worth it in that sense. The trouble is you become more a paper work company, what you do changes, and the job of successful electronics ta kes ever lower priority as it gets messed about by a heavy dose of genuine issues, trivia, irrelevance bs mixed together. I used to find it frustratin g.
pass it on to the customer. Thus the customer gets whatever extra requireme nts they want - almost - but they pay for it all plus profit.
nterproductive. But the customer's paying.
Willingness to sacrifice profit in mil spec work? I don't think so. Maybe t hings have changed now, but I doubt it.
NT
No one said mil spec but sure. Given competition, profit is one part of the cost. If you're saying there is no competition in mil spec work, well...
I've seen military primes tell subs to increase pricing to them.
At one meeting, in a motel room, after we were all close to agreed, I said "Increase the price by $20,000 and give it to me." Everybody laughed and added the 20K. But I never got it.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
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emands it, it's worth it in that sense. The trouble is you become more a pa perwork company, what you do changes, and the job of successful electronics takes ever lower priority as it gets messed about by a heavy dose of genui ne issues, trivia, irrelevance bs mixed together. I used to find it frustra ting.
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ll pass it on to the customer. Thus the customer gets whatever extra requir ements they want - almost - but they pay for it all plus profit.
counterproductive. But the customer's paying.
e things have changed now, but I doubt it.
shakes head.
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