Seriously, what sadist saw a flat PCB surface, flat pick and place machine heads, and said “lets create a round component”?
Joking aside I am genuinely curious what advantage the MELF design actually offers. I know they’re a pain to get a machine to place properly, they have more solder flow issues than components with flat leads, and they seem like they would be harder to manufacture too. So why a round component? Anyone here have any insight on why they even exist?
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Working at an OEM that designs their own boards I’ve often wondered the same thing. We only have one designer that used them but they were such a pain in the ass on the pick and place machines. Lots of drops
If you see that designer, you should ask them. There must be a reason they use them other than being a misanthrope.
I spent 3 hours fighting with a Fuzion tonight and even with the special MELF heads it drops enough to reliably jam up other component feeders. Unfortunately our customers pick what exact parts we use so we can’t just change them out for something equivalent but less hateful and I don’t communicate with them so I can’t ask why.
I’m starting to think MELFs are just pushed by big component to get people to buy more components (because the machines throw half of them on the ground.)
You guys made me curious, so I checked Wikipedia:
Despite their handling difficulties, and in the particular case of MELF resistors, they are still widely used in high-reliability and precision applications where their predictable characteristics (e.g., low failure rate with well-defined failure modes) as well as their higher performance in terms of accuracy, long-term stability, moisture resistance, high-temperature operation far outweigh their disadvantages.
I may be a simpleton, but I’ve always thought that MELF was just old school SMD, where the shape hadn’t evolved yet from the though hole package.
My thought was based on all the old junk I’ve repaired, where the older it was the more likely MELF seemed to be.
I haven’t designed with MELF before, but wouldn’t it make sense for assembly operations to add a MELF fee?
From what I’ve seen I am now inclined to believe the reason people use them is because they’re more durrable and stable environmentally speaking. I imagine the reason you see them less in newer electronics is just because chip resistors and such have gotten better to the point where MELFs usually aren’t required.
As far as the additional fee, I’m not on the pricing side of things but I sure hope we charge extra because the damn things are the bane of my existence.