mentally ill (paralyzing greed) mechanical designers? (bad product design) - Page 1
Forum section: electronics / general

author: CopperCone
author_rank: Super Contributor
timestamp: July 02, 2017, 07:02:05 pm
content: Are these guys paid to piss people off and drive them to the loony bin?I am working on some expensive RF equipment (used to cost probably 40,000$), and the design decisions I see just boggle my fucking mind. Thanks HP.To remove one of the RF boards, you basically need to entirely strip the unit down. This means removing about 5 RF cans and undoing complicated double side assembly with circuit boards sandwiched together, just to remove one circuit board, the top of which is directly accessible. Why? It saved them money on literary one screw.I can't even phantom going through all the work to replace a shitty SMB connector. Instead, I have decided to dremel a slot into the RF can and use special solder to fill it, and insert a SMB connector thats been machined down to fit.If I paid the money they were asking for it back then, boy, I would be under investigation for telephone threats. My number would be blocked from HP at the very least.A few times I open equipment and think, wow, if they spent the extra 3$ on a fucking bracket, this repair job would go from 2 hours + great risk of equipment damage to about 5 minutes.for the money and insane markup, they really could have done a nicer job.I wonder if this came about because of company programmed 'price harping', i.e. some guy just basically nags people to reduce costs without even thinking about what the fuck he is saying

author: Cubdriver
author_rank: Unknown
timestamp: July 02, 2017, 07:50:00 pm
content: Care to share what piece of equipment this is? Perhaps there was a reason other than cost cutting that the design was used, and knowing what it is might help to explain the logic behind it. HP usually does things for good reason, and their equipment in my experience is typically well designed.-Pat

author: German_EE
author_rank: Super Contributor
timestamp: July 03, 2017, 09:37:46 am
content: I've seen this before on a couple of pieces of equipment including a Dell PC. The problem is that the unit is built on an assembly line from the inside out and as more bits are added on it becomes difficult if not impossible to access components that were first in the assembly list. I've done it myself, I have a power supply in my ham shack where I need to remove the rear heatsink to trim the voltages, fixing that is on my TO DO list but for now I have more exciting stuff to tackle.Oh yeah, that Dell PC. To change the power button you need to remove the CPU heatsink, then the cowling around the heatsink, then the motherboard, then a plastic piece holding the fan, then you can remove the PCB on the front that has the cheap and nasty pushbutton switch on it that they use for power.

author: Electro Detective
author_rank: Super Contributor
timestamp: July 03, 2017, 09:56:28 am
content: Quote from: CopperCone on July 02, 2017, 07:02:05 pmYESand...YESIt's obvious THEY don't want anyone using older gear,and make sure the local tech can't get parts easily or at fair cost for older or newer gear,to facilitate repair at a price to keep tech and customer happy

author: mc172
author_rank: Frequent Contributor
timestamp: July 03, 2017, 11:37:38 am
content: Quote from: Electro Detective on July 03, 2017, 09:56:28 amRubbish. Given the kind of gear that HP made, how are they supposed to design anything using 100% or even 50% off-the-shelf parts, yet get all of the features into as small a package as possible, etc? To say that the engineers doing the design work are engineering in nightmares and/or impossible to source parts is bonkers. You clearly haven't ever designed anything for use by people other than yourself at home.And why does everyone always assume there's a massive mark-up on expensive equipment?You are never going to have a piece of RF gear requiring no custom parts, unless you consider 1 MHz to be "RF". There must be a reason that HP chose to do what they have in the OP's situation. If you can't see why they have done it then you are almost definitely missing why they did it. Perhaps put some pictures up or at least tell us what gear it is.

author: dmills
author_rank: Super Contributor
timestamp: July 03, 2017, 02:29:41 pm
content: Yep, been my experience that almost NOBODY deliberately designs test gear that is impossible to work on.Sometimes it happens anyway, all design is a compromise, and you do not always get it right, even if 'right' is easy to work on, as opposed to 'light weight' or 'small' or 'low power' or 'low spurs' or whatever.I have a couple of old TF2019A signal generators, as it turns out the common failure is a bias resistor in a hybrid amp module used all over the place, not to hard to add an external resistor, and the RF enclosures are hinged, but there is a LOT of single wires snaking around the insides of the thing, real 1980s design. Nobody could have seen the amplifier hybrids being the common failure back when it was designed, but they are, and it is just unfortunate that the job is so tedious. Sometimes you loose even when you think you should have won.Another thing that is sometimes not understood unless you work as a design engineer is that usually it does not have to be perfect, good enough is good enough if it gets you to market 6 months sooner.73 Dan.

author: floobydust
author_rank: Super Contributor
timestamp: July 03, 2017, 04:53:27 pm
content: I think it's a consequence of using 3D CAD to design products and enclosures. MecE's don't get a chance to think how the thing is assembled or serviced.They spin and pan in Solidworks all day long and fret over bend radius and injection-mold reliefs.If I point out how difficult it is to put together/take apart the answer is "it's Manufacturing's problem"

author: dmills
author_rank: Super Contributor
timestamp: July 03, 2017, 05:43:13 pm
content: Ah yes, mechanical 'Engineers' who have only ever driven CAD, and not even seen a lathe, mill or press brake (Never mind made anything on them), don't get me started.See also why one should not set the rounding in solidworks 2D output to 'nearest mm', even if it makes the drawings look tidy.Being able to get the riveter head into the box is almost as important as being able to get the board into the box, I have seen both fails.Solidworks is a wonderful tool, but the potential for stupid rises more then linearly with the power of the tool (We see the same thing with the 'but it works in Proteus!' crowd in the electronics game, then you note all the missing decoupling).Regards, Dan.

author: tszaboo
author_rank: Super Contributor
timestamp: July 04, 2017, 03:28:03 pm
content: I've worked on stuff, which had a lot of mechanical design. Water cooled electronics, ending up in a cabinet weighting some 600kg. You cannot negotiate with the mechanical design team. And they dont care. We had problems, like broken connectors, because of the illogical way of connecting everything together. Sometimes there was no way to access screws, because it was in a illogical place. You needed like a special screwdriver, and there was one at the company exactly for this. Other places, it was using impossible to place push bars and brackets, just to avoid screws. Next to electronics, so you had a fair chance to break something when you were assembling it."It looks fine on my screen, what do you mean its impossible to assemble?" And stupid shaped bus-bars soldered into the board, reducing yield and stressing it constantly. Did I tell you about the time, when I had to redesign a PCB because of the stupid metal part it attaches to?Every time, you need to discuss something with the mechanical designers, expect trouble.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 04, 2017, 04:17:58 pm
content: Sometimes bad design decisions happen - usually not on purpose. Especially difficult to service parts are common. For a while, some 10 years back is seemed the car designers tried to make changing the bulbs as difficult as possible. I suddenly stopped when that was a rumor that France might require them to include all the tools needed to change the bulb.I remember a jig-saw. To replace the switch one had to take apart the greasy gear box. The second bad point on the design was a switch that is not dust protected and at a somewhat dirty spot - so a bad switch was kind off expected point of failure.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: July 04, 2017, 05:19:30 pm
content: 1. Watch out for cost-reduction cycles where Mechanical or Manufacturing tries to replace a matrix of holes with a set of slots. Your task: explain to blank stares why slots are bad for EMC.2. Watch out for oddball thread sizes. In America the common grounding screw is 10-32 (Size 10, 32 threads per inch (Same as rack-mount screws)). I have products that are made in America that use: M5! Close, but not compatible. It sometimes happens that someone needs to replace the screw, and then the threads get stripped out.3. Products that have mix of lengths. Standard and Metric on the same unit, 6-32 in 1/4, 5/16, 3/8, AND 1/2, etc.4. Wiring harnesses designed by Mechanical engineers.

author: mc172
author_rank: Frequent Contributor
timestamp: July 04, 2017, 08:51:05 pm
content: Quote from: NANDBlog on July 04, 2017, 03:28:03 pmSounds like you had the displeasure of working with an incompetent team. Work with a competent mob and you'll find that they're more than reasonable and end up with better solutions than the original ones anyway as they're allowed more time to think about it.

author: Cubdriver
author_rank: Unknown
timestamp: July 04, 2017, 08:58:04 pm
content: Several days later I'm still quite curious as to what the particular HP instrument that caused such angst to the OP is.-Pat

author: timb
author_rank: Super Contributor
timestamp: July 04, 2017, 10:04:42 pm
content: Quote from: blueskull on July 04, 2017, 09:56:15 pmThere takin' are jurrrrbbbssss!

author: CopperCone
author_rank: Super Contributor
timestamp: July 05, 2017, 12:03:46 am
content: Quote from: blueskull on July 04, 2017, 09:56:15 pmThis is like selling a makeup kit to make yourself look like obama. Or perhaps selling sheep skin camouflage to wolves LOL

author: Rerouter
author_rank: Super Contributor
timestamp: July 05, 2017, 02:30:28 am
content: As someone who has just started using kicads 3D viewer and export function, i have to say it helps to drag the mechanics back into the ee domain, and knowing things like PCB thickness tolerance helps with slot insert casings.Though i will admit a few of the products i have built do need to be disassembled in a certain order (microcontroller card needs to be pulled before the relays or they will rub, etc)And as much as i wish it wasn't the case, having grossly different copper densities can make the pcb layout become mechanical, its all fun and games until your board has a 1cm hump in the center that radius's to the edge. (Though you can kinda cheat it on a 4 layer if the internals and external pairs are similar)Though i have seen some very dumb products before, e.g. to remove a devices sim card means removing a cover that a lithium battery is attached to, the battery lead is 14mm long to the pcb behind the cover, meaning you have to disconnect and reconnect the lead with pliers before the cover can be removed. if you tug the cover the wires will pull out and short out the lithium battery...

author: CopperCone
author_rank: Super Contributor
timestamp: July 05, 2017, 02:38:24 am
content: stuff like this makes the compliance laboratory a nightmare.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 05, 2017, 03:17:23 am
content: Quote from: floobydust on July 03, 2017, 04:53:27 pmThanks for sharing.I am also in manufacturing, (automotive modules) and have similar experiences.Plus they love heat stakes and all sorts of blind assemblies.Troubleshooting is next to impossible.Did I mention that the units are potted?

author: CopperCone
author_rank: Super Contributor
timestamp: July 05, 2017, 10:40:27 pm
content: what is a heat steak?

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 06, 2017, 01:06:45 am
content: stake, not steak.It is used to mate plastic parts together.Think of it as a plastic rivet, which is pressed with a hot element that melts it into shape, to permanently hold the two pieces together.

author: BrianHG
author_rank: Super Contributor
timestamp: July 06, 2017, 02:35:12 am
content: Quote from: schmitt trigger on July 06, 2017, 01:06:45 amAre you sure it's not press with an ultrasonic welder, which melts the plastic inside the peg going into the stake, leaving no marks on the outside. Basically invisible welds.

author: BrianHG
author_rank: Super Contributor
timestamp: July 06, 2017, 02:49:23 am
content: Good points here. I'm commissioning a custom exercise bike for production and sale later this winter. I'm gonna have the engineer read this thread and ask that the design is 100% easily serviceable.

author: ebastler
author_rank: Super Contributor
timestamp: July 06, 2017, 05:54:00 am
content: Quote from: Cubdriver on July 04, 2017, 08:58:04 pmIndeed. Strange that CopperCone has made multiple follow-up posts, but not answered this question.I think this thread is more about feelings than facts.

author: CopperCone
author_rank: Super Contributor
timestamp: July 06, 2017, 11:00:54 pm
content: the person still might work at HP I don't want someone to get fired/transfered/etc I hope it was done because of exrreme hang over, its fairly recent.. not some 1960s thing, large companies probobly have corporate gestpo reading these forums.I went to fedex the other day.. they basically have 1940's germany postings on the walls about getting money if you provide them with information that gets someone fired. They specifically say they will give you 5 grand if you get someone terminated with your information................

author: mc172
author_rank: Frequent Contributor
timestamp: July 06, 2017, 11:32:40 pm
content: Quote from: CopperCone on July 06, 2017, 11:00:54 pmExtremely unlikely. They are far too busy enforcing idiotic clear-desk policies, whereby the design environment is indistinguishable from a call centre, and presenting "black engineer of the month" awards, despite there being no such thing as "Asian engineer of the month" or "white engineer of the month", or whatever.

author: timb
author_rank: Super Contributor
timestamp: July 07, 2017, 01:33:04 am
content: Quote from: CopperConeYou've clearly never run a business before. If your employees were stealing from you, literally taking food out of your mouth, I'm sure you'd change your tune pretty quick.Awhile back FedEx was having a big issue with employee theft. Drivers were literally stealing goods and cash from packages then marking the packages delivered. There was also issues with the warehouse employees opening packages and stealing the contents.Otherwise honest people knew this was going on, but didn't report it because they didn't want to get involved. It's the same thing you see with street crime, people don't want to get involved if it doesn't directly concern them. People are inherently selfish.That's why offering a reward works; it taps into that selfishness. FedEx's monitory incentives are no different than Crime Stoppers and other programs that offer a reward if a tip they provide leads to a conviction. You're essentially bribing people to be honest and come forward. It's not a perfect system, but we don't live in a perfect world.Finally, I seriously doubt providing the model number of the device you've been ranting about will get anyone fired. I mean, have you ever watched any of Dave's videos? He's said much worse about the design of products during tear downs.Short Version: Quit being such a delicate flower and provide a model number and/or pictures. Otherwise there's no context to your original post, making it pointless.

author: aargee
author_rank: Frequent Contributor
timestamp: July 07, 2017, 02:10:40 am
content: The old version of the company I work for used to rotate field service engineers in through the design section to give the designers a 'reality' check on serviceability.Not so now days, then there's the whole thing on making stuff un-repairable anyway.

author: ebastler
author_rank: Super Contributor
timestamp: July 07, 2017, 05:08:40 am
content: Quote from: CopperCone on July 06, 2017, 11:00:54 pmInteresting theory... May I offer another one?You are worried that, as soon as you disclose the actual model number, someone on the forum will explain to you why the design choice is perfectly reasonable... Or maybe in the meantime you have realized yourself what the correct disassembly sequence is, and that the design is alright?

author: floobydust
author_rank: Super Contributor
timestamp: July 07, 2017, 05:50:22 am
content: The whole movement to get rid of fasteners, screws/bolts leaves us with this pry apart nightmare.I get that Manufacturing people hate putting in screws. OHS repetitive stress injury etc. but the damn puzzles MecE's come up with... 50/50 change of wrecking something taking it apart. Or blood after the thin pry tool slashes you

author: Cubdriver
author_rank: Unknown
timestamp: July 07, 2017, 07:33:11 am
content: Quote from: CopperCone on July 06, 2017, 11:00:54 pmUhhhh... You do realize that HP stopped manufacturing test gear 18 years ago when they spun the division off as Agilent Technologies back in 1999, right? If the guy is still there through TWO corporate restructurings and the associated name changes, I'd bet his position is reasonably secure.-Pat

author: Kleinstein
author_rank: Super Contributor
timestamp: July 07, 2017, 07:51:06 am
content: Quote from: Tomorokoshi on July 04, 2017, 05:19:30 pmI bad example of mixing metric and imperial threads is with some GPIB connectors. These seem to come with both types.A really funny part a one came across was a ball bearing that was 3/8" or 5/16" on the inside and 19 mm (not 3/4") on the outside. So mixed measures on a single part.

author: tszaboo
author_rank: Super Contributor
timestamp: July 07, 2017, 08:22:29 am
content: Quote from: CopperCone on July 06, 2017, 11:00:54 pmDoes enyone ever get fired for bad design decisions? Come on! The only way you might get fired, if some big manager makes you a scapegoat for a failed product.

author: Pinkus
author_rank: Frequent Contributor
timestamp: July 07, 2017, 09:52:06 am
content: oh man, I am so glad I am using the metric system all day.

author: VK3DRB
author_rank: Super Contributor
timestamp: July 08, 2017, 04:59:48 am
content: The problem is (young) mechanical engineers generally do not have any experience servicing equipment. The best mechanical engineers are often brought up on farms, or have worked with their dad restoring cars in the workshop and the like. Those brought up in families with servants become pretty useless adults when it comes to practical aptitude and ability.Inexperienced electronics engineers not understand the importance of back annotating a schematic, or the orientation of tiny devices around things such as EMI shielding cans, or even putting in ground test points in convenient places. Ideally, all electronics engineers should have practical experience debugging boards in component level and have experience in an electronics manufacturing environment before being let loose designing products.

author: CopperCone
author_rank: Super Contributor
timestamp: July 08, 2017, 01:49:49 pm
content: I would not butcher 20+ghz equipment with a dremel unless it was for good reason.

author: mc172
author_rank: Frequent Contributor
timestamp: July 08, 2017, 10:54:52 pm
content: I think you're talking bollocks mate. Pics or it didn't happen.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 10, 2017, 02:00:25 pm
content: Quote from: Pinkus on July 07, 2017, 09:52:06 amIf one is doing any sort of scientific analysis or design engineering, metric is really the way to go.One may learn simple stuff like converting inches to millimeters, but compound units like torque, are very challenging. Try to convert pound-foot to ounce-inches on your head.True, there are on-line converters and many downloadable apps, but nevertheless............