Forum: Reliability & Maintainability Questions and Answers

Add a Message About this forum
Newer messages are at the top

Previous 5 messages

Posted by: Bahman Kaboodrangi (Bahman.Kaboodrangi-Da@Boeing.com )
Organization:Boeing
Date posted: Thu Jan 6 16:45:19 US/Eastern 2000
Subject: Base Failure Rate for Switches Notice1 vs Notice2
Message:
Why is the Base Failure Rate (Lambda B)for Switches in Notice 2 is worse than Notice 1. Please provide reason for the difference between the two versions.

Replies:
Switch Failure Rates
Bruce Dudley Wed Jan 12 10:34:42 US/Eastern 2000

Reply to this message


Posted by: Floyd Kreuze (floyd.kreuze@sgp.honeywell.com )
Organization:Honeywell SGP/MSPO
Date posted: Thu Jan 6 10:10:11 US/Eastern 2000
Subject: Source of Latest PEM Field FR Estimates
Message:
Where can I find some information on the very latest estimates of field failure rates for plastic encapsulated microcircuit (PEM) devices? Any leads or suggestions would be appreciated. Thanks.

Replies:
PEM Failure Rate Data
Bruce Dudley Tue Jan 11 13:08:26 US/Eastern 2000

Reply to this message


Posted by: Xiangping,Wu (7815@notesmail.huawei.com.cn )
Organization:Huawei Tech.Ltd.,China
Date posted: Mon Jan 3 3:14:14 US/Eastern 2000
Subject: Reliability Prediction
Message:
I did a reliability prediction several days before.This system consists of about 10~15 PCBs,and there are average 500 components on each PCB.I used 217F and Bellcore respectively.MTBFs are 5800h and 40000h.Is that reasonable?
After that,I saw a reference about similar system of other company(a famous company).In that reference,they claim their system'MTBF is 1000 years(failure rate is 111 fits).Oh my god!Is that possible?Or am I wrong?

Replies:
Reliability Prediction
bruce Dudley Wed Jan 5 14:14:21 US/Eastern 2000

Reply to this message


Posted by: Benny (saflt@pacific.net.sg )
Organization:ST Aerospace
Date posted: Thu Dec 30 1:29:03 US/Eastern 1999
Subject: Derating guidelines for SMT
Message:
I am trying to find some derating guidelines with regards to Surface Mount Technology (SMT), especially in the area of microcircuits. Are such guidelines available? In general, are there any differences between the derating factors for SMTs compared to MIL-HDBK-338?
I understand that the latest derating study conducted by the former U.S Air Force Rome Lab in 1992 can be found in the technical report, RL-TR-92-11 (ADA253334). Does this study cover SMT? Please advise.Thanks.

Replies:
SMT Derating
Bruce Dudley Tue Jan 4 14:22:55 US/Eastern 2000

Reply to this message


Posted by: Mike D'Aquila (duhrange@aol.com )
Organization:Independent Consultant
Date posted: Mon Dec 20 10:23:09 US/Eastern 1999
Subject: The Applicabilility of Reliability Prediciton Techniques
Message:
I, first of all, extend an apology to all RAMP professionals who conclude from readnig this question that I am trivializing the scope and depth of the [correct]answer. I do not mean to, however: While spending many years in the COTS and defense contractor environments, on numerous occasions I personally participated ( or took notice of ) in debates about - for instance - using some interaiton of *217* as a prediction technique for, say, a next generation COTS processing architecture vs. a Bellcore-based algorithm or even, perhaps, one that considered Weibull or physics-of-failure, or whatever hybrid was in vogue at the time. I even recall the Redstone Arsenal organizational debate that was founded on a belief that the USA should move away from 217 totally, as the default technique.
Yes, there were many valid arguments against using 217 as a technique in the COTS development arena - one being that the appendices never were able to keep up with the lightship speed of the day's ic-development race to revenue fame and glory....i.e. always "..one step behind.."...or whatever. Generally, too, the knowledged concluded that 217's felxibility with setting Quality Factors allowed for too much subjectiveness so as to cloud viability and consistency. And, in the end, certain RAMP-guys said that actual measurement proved that 217 was a pessimist. So, with all that drivel comes my question: Are there any current "white paper" or "treatise" type discussions known to RAC where this the applicability of one technique vs another for COTS product development is at the focus ? Even though I have not looked into this for 18-24 months, I am confident that the synchronization between academia and commercial product development is again skewed......even more, perhaps. I read in one of the FAQs teh fact that some believe that 217 can be 2-3 times too pessimistic, or more, as compared to actual demonstration. PRISM, as I understand it, it to close this gap ?????? Thanks for your time........ Mike D'Aquila, 603.434.8231, "duhrange@aol.com"

Replies:
Reliability Prediction
Seymour Morris Mon Dec 20 11:44:14 US/Eastern 1999

Reply to this message


Next 5 messages

| 1...5 | 6...10 | 11...15 | 16...20 | 21...25 | 26...30 | 31...35 | 36...40 | 41...45 | 46...50 | 51...55 | 56...60 | 61...65 | 66...70 | 71...75 | 76...80 | 81...85 | 86...90 | 91...95 | 96...100 | 101...105 | 106...110 | 111...115 | 116...120 | 121...125 | 126...130 | 131...135 | 136...140 | 141...145 | 146...150 | 151...155 | 156...160 | 161...165 | 166...170 | 171...175 | 176...180 | 181...185 | 186...190 | 191...195 | 196...200 | 201...205 | 206...210 | 211...215 | 216...220 | 221...225 | 226...230 | 231...235 | 236...240 | 241...245 | 246...250 | 251...255 | 256...260 | 261...265 | 266...270 | 271...275 | 276...280 | 281...285 | 286...290 | 291...295 | 296...300 | 301...305 | 306...310 | 311...315 | 316...320 | 321...325 | 326...330 | 331...335 | 336...340 | 341...345 | 346...350 | 351...355 | 356...360 | 361...365 | 366...370 | 371...375 | 376...380 | 381...385 | 386...390 | 391...395 | 396...400 | 401...405 | 406...410 | 411...415 | 416...420 | 421...425 | 426...430 | 431...435 | 436...440 | 441...445 | 446...450 | 451...455 | 456...460 | 461...465 | 466...470 | 471...475 | 476...480 | 481...485 | 486...490 | 491...495 | 496...500 | 501...505 | 506...510 | 511...515 | 516...520 | 521...525 | 526...530 | 531...535 | 536...540 | 541...545 | 546...550 | 551...555 | 556...560 | 561...565 | 566...570 | 571...575 | 576...580 | 581...585 | 586...590 | 591...595 | 596...600 | 601...605 | 606...610 | 611...615 | 616...620 | 621...625 | 626...630 | 631...635 | 636...640 | 641...645 | 646...650 | 651...655 | 656...660 | 661...665 | 666...670 | 671...675 | 676...680 | 681...685 | 686...690 | 691...695 | 696...700 | 701...705 | 706...710 | 711...715 | 716...720 | 721...725 | 726...730 | 731...735 | 736...740 |

Add a Message About this forum