[HN Gopher] Techniques and strategies for prototyping electronic...
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Techniques and strategies for prototyping electronics circuits
(2020)
Author : brudgers
Score : 70 points
Date : 2022-08-20 21:37 UTC (2 days ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| mikewarot wrote:
| Well, this certainly looks like a great bridge into the world of
| surface mount parts for me. I was doing PCBs using paint programs
| back in the 1980s for the few boards we needed to repair 1960s
| vintage control systems.
|
| I'll get my $200 cnc mill going for the next step, some day.
| swamp40 wrote:
| We do zero prototyping like this anymore. Actually, we almost
| never carved copper plates anyway, we would just get perf boards
| with plated holes and wire everything together.
|
| Everything gets a pc board made now. If you can't buy a dev board
| from the mfg or a 3rd party, then you make your own.
|
| Surface mount mostly killed it off. But I don't miss spending
| hours looking for a problem that turns out to be just some
| breadboard issue that broke when you jiggled it wrong.
| hengheng wrote:
| I've been waiting for the 3d printer conversion that deals with
| all the drilling, positioning, etching, gluing together
| multilayers, and eventual pick and place with optical
| inspection.
|
| Someone has to do this, eventually electronics hardware
| prototyping has to stop lagging behind several decades.
| swamp40 wrote:
| Someday you will start with a sheet of copper with green
| soldermask. A laser will cut out the traces then take off
| just the masking where the component leads need to be
| soldered.
|
| They can pretty much do that now. But nobody has a nice
| solution for thru-holes yet. And single sided boards are
| pretty boring.
| seventytwo wrote:
| This wouldn't work because you have to somehow remove most
| of the copper under the soldermask without removing the
| soldermask.
| jeffbee wrote:
| Why would that make economic sense when the PCB makers
| already have the necessary machines and I can get a small
| 2-layer board delivered straight to my desk for a few tens of
| dollars? Electronic prototypers are not waiting around for
| some hoped-for long-tail revolution, because it's already
| possible to click a button in your EDA program and get
| hardware via fedex almost instantly. And we've had this
| capability at monotonically decreasing prices for over 20
| years.
| svnt wrote:
| Because tomorrow is not almost instantly, except in the
| land of circuit boards.
|
| Your argument doesn't pass a self-integrity check. You can
| get boards for a few tens of dollars. You won't get them
| today.
|
| You can get boards tomorrow, or if you happen to be close
| to a fab and submit your order before lunch maybe same-day.
| This doesn't cost tens of dollars.
| r3012 wrote:
| I think the main thing is it's really rare to just have
| one project in the works anymore. So you buy the 5day
| turn and work on something else in the interim. If
| somehow you really blew it in the project planning stage,
| and you simply must have it now, then I guess it's kinda
| a toss up. In those emergencies rarely does cost matter
| but definitely your geographic location will limit
| options.
| jeffbee wrote:
| Yeah but neither will a multi-axis robot that can etch
| and drill and pick and place and solder. It's going to
| cost an absolute fortune even with fantasy leaps of
| technology.
| naasking wrote:
| > Yeah but neither will a multi-axis robot that can etch
| and drill and pick and place and solder.
|
| So simplify: mill instead of etching, which also handles
| drilling. This needs 3-axis movement, which is all you
| need to drop solder paste on pads and do pick and place
| too, you just need a tool changer for each task. Not a
| trivial project either, but it's been done and certainly
| not for an absolute fortune.
|
| Final step is reflow soldering, and this can be done
| using just a heated plate [1]. This all seems doable for
| most hobby sized PCBs.
|
| [1] https://www.solderreflowplate.co.uk/
| xyzzy123 wrote:
| Yes; milling is fiddly but because the forces are so low
| (and you can reduce the mechanical accuracy needed with
| depth probing), it's possible to do reliable pcb milling
| for similar to cost of decent fdm printer.
|
| People are doing this today but everything is jank,
| nobody's repackaged it with prusa-like reliability at
| hobbyist prices AFAIK.
|
| Ideally if you could get v thin copperclad with a
| substrate that doesn't produce toxic dust, with the right
| software and jigs you could produce "basic" multilayer
| boards(1) with 1 "pin aligned" flip and a few manual tool
| changes for drilling etc.
|
| It all seems possible today but has never been packaged
| nicely and made cheap, I suspect because the market is
| not big enough.
|
| (1) one big issue... the boards produced would be vastly
| inferior to "real" multilayer boards, would mainly be
| usable at low frequency, you could get complex layout /
| routing but they'd suck at high frequency and in several
| other ways. You would need to relayout / redesign to
| target a "real" process, which is somewhat undesirable
| for prototyping.
| [deleted]
| bsedlm wrote:
| but it's all about the managed lag.
|
| how else would all those billions in R&D would be worthwhile
| for investment institutions?
|
| as I see it (and stretching my reasoning), the lag is also
| part of what maintains the prestige of many academic and
| research organizations.
|
| the billions in R&D are not all about the outcomes, a lot of
| them are spent making sure it's really damn hard for any
| rivals to catch up. how exactly? I cannot know but I can
| infer it's got a lot to do with having nobody able to see the
| whole picture, anybody can only know either how to design the
| chips, xor how to build them.
|
| if everybody is as good as MIT, then MIT is no longer MIT.
| somebody has got to make sure some of those 3rd party (and
| far away) institutions stay there, in the back.
|
| if everybody could do "2nm" process (whatever that means),
| then TSMC wouldn't be ahead of Intel, and so on...
| buescher wrote:
| Some of the prototypes he shows in his videos are really
| beautiful, or I'd just be echoing the "just lay out a board"
| chorus. There are people you will never get away from this kind
| of prototype/one-off construction and that's OK. You'll still see
| it occasionally in PCB RF design, too. I.e. if you want to do a
| bunch of experiments (antenna designs, etc) today and don't have
| a board mill.
|
| But if you are looking for advice on learning to do this stuff,
| it's a backwards approach for 2021.
| seventytwo wrote:
| If you have the materials on hand, making one of these boards
| will be quite a bit faster and cheaper than laying something
| out and getting it quick-turned.
|
| The downside is that the quality won't be as high, you'll only
| get a single copy (or however many you make by hand), and you
| can't reuse the work in a new design like you could with a CAD
| design.
|
| Still, there are definitely some advantages to being able to
| whip together a test unit like this.
| buescher wrote:
| Sure. It depends on how much you value time, how much else
| you have to do, and what the goal of the design is. I don't
| work or lead on one-offs much anymore, myself.
| neilv wrote:
| These look like great tips from someone who knows their stuff.
| squarefoot wrote:
| Yes, definitely. He showed a mix of through hole, SMD,
| Manhattan and Wirewrap techniques proving that he knows what is
| the best approach for each building need. I also liked how he
| used copper foil to add ground planes to perf boards. That is
| also used in non-cheap electric guitars to screen pickups slots
| from induction of mains hum. Also, I couldn't recommend more
| the use of leaded solder, which works so much better than
| leaded one.
| jeffbee wrote:
| I also use standard solder at home but we used lead-free
| solder at work when I had was in a hardware engineering org
| and it really didn't seem to cause trouble. I think people
| who don't have good success at first with lead-free are
| probably using the wrong tip size, have set their iron to the
| wrong temperature, or have an iron with poor tip temperature
| control. You see the same troubles when beginners use leaded
| solder, but people forget about those early experiences.
| skybrian wrote:
| Since I'm still somewhat bad at soldering: what are the
| symptoms of having the wrong tip size?
| inphovore wrote:
| If you're new to soldering, a good "tip" is to use a
| copper coil rather than a sponge to clean the tip. And
| keep the tip tinned (keep adding a bit of solder and
| jabbing it off in the coil.) this prevents thermal shock
| and prolongs the life of the iron's tip!
|
| https://www.adafruit.com/product/1172
| buescher wrote:
| If you have a tip that is too small, then you will not
| have enough heat, i.e. thermal flow, getting to your
| solder joint. Note that heat is different from
| temperature! A bic lighter is hotter than your oven but
| it will not roast a turkey.
|
| Symptoms of too small a tip - it will take too long to
| heat the solder joint. Pads and traces can lift and other
| things thermally connected to the joint may be damaged
| just like they will if the tip is too hot, but your flux
| may not activate and your solder will flow badly (or not
| at all) or make a cold joint like the tip is too cold.
|
| Too large a tip and you can't do fine work or you rapidly
| heat everything around your part to soldering
| temperature.
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