• rtxn@lemmy.world
    link
    fedilink
    English
    arrow-up
    43
    ·
    2 days ago

    I used to work on an SMT line, and pin in paste was the bane of my fucking existence. The parts (mainly connectors) were rarely within tolerance, and a leg or two would consistently miss their holes, if not outright rejected by the inserter.

    • Yggstyle@lemmy.world
      link
      fedilink
      English
      arrow-up
      39
      ·
      2 days ago

      So if I’m reading that right - higher failure rate on the line but those that passed I’d imagine have a higher rate of success?

      • rtxn@lemmy.world
        link
        fedilink
        English
        arrow-up
        49
        ·
        2 days ago

        The main problem was that it interrupted the line. We’d have to stop and inspect each product, then reposition or replace the connectors, before the reflow oven. It also ran the risk of damaging the connector, the PCB, or even the inserter head if the insertion force was too high. We had a higher rework and scrap rate compared to similar SMD-only products, but using pin in paste meant that wave soldering could be skipped altogether, and I guess someone above my pay grade determined that it was better in terms of finances.

        This is just my own experience. I don’t know Rpi manufacturing practices.

        • bluGill@fedia.io
          link
          fedilink
          arrow-up
          6
          ·
          1 day ago

          It is very common in manufacturing for removing a process step to save a large pile of money even if more human labor is needed.

          As others have already implied there is always the possibility for technology to get better and thus the inspections not be needed, or perhaps automating the inspections.

          Accounting is often weird. It makes no intuitive sense why just-in-time should save so much money, but it does.

          • WildPalmTree@lemmy.world
            link
            fedilink
            English
            arrow-up
            4
            ·
            1 day ago

            I feel like just-in-time is one of the things that makes most intuitive sence. You used to tie 1M in Inventory and now you tie 100k. Stick the other 900k in a bank account (worst case scenario) and collect the interest.

        • Yggstyle@lemmy.world
          link
          fedilink
          English
          arrow-up
          12
          ·
          2 days ago

          That’s some interesting insight - thanks 👍

          I’ve done some sm work but as repairs and upgrades … it definitely was /easier/ to remove and replace: that was for sure. I’m unclear on if it ultimately had a higher real world failure rate though.

          Personally I’m hopeful that their reasoning for this is increasing the quality of what does hit shelves even if there is a higher on line failure rate. They can’t always be the cheapest (and recently haven’t been) but if they can double down on “It just works” for a slightly higher price… I’m here for it and I imagine other makers likely will be as well.

    • ozymandias117@lemmy.world
      link
      fedilink
      English
      arrow-up
      11
      ·
      2 days ago

      So, would your suspicion be that it’s causing them more failed boards in production?

      I guess if it’s reducing returns, that might be something they’re accepting as a tradeoff?

    • Goretantath@lemm.ee
      link
      fedilink
      English
      arrow-up
      5
      ·
      2 days ago

      How long ago was this? Could the process have become more acurate in the time you’ve been away from it?