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I am designing a circuit board and replaced some through hole headers with surface mount ones to try and reduce a board house price which uses a pick & place machine. The rational is that through hole components require extra steps.

I sorted DigiKey to get the surface mount headers which I wanted and made a mental note that some of the headers had plastic hats on them while some do not. header with a plastic hat

Not paying attention I selected a component and when copying the sourcing information into kicad I noticed that the only packaging option this component has is being delivered in a "bag". This sounds all jumbly. I then noticed that this component doesn't have the plastic hat that some of them have and am wondering if I just inadvertently picked a component which isn't pick & place friendly. So I was wondering if this is a thing that people know to watch out for.

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    \$\begingroup\$ The plastic hats will allow a vacuum pen to pick them up ... if they are correctly oriented in the first place. Which probably doesn't happen with a plastic bag. I'd be looking for these on a reel or in a tube... \$\endgroup\$
    – user16324
    Commented Oct 30, 2020 at 19:28
  • \$\begingroup\$ Basically, loose parts like this either have to be applied by hand, or the operator needs to arrange them in a tray and add a machine-compatible method to lift the part (like a piece of Kapton tape) so the machine can place them. \$\endgroup\$
    – hacktastical
    Commented Oct 30, 2020 at 19:37
  • \$\begingroup\$ Yeah I'll be willing to go a bit further than @BrianDrummond did and just say; Yes, pick-and-place machines are definitely allergic to "bags of parts". At least in the sense that if someone at the fab doesn't carefully put all the parts in a tube before mounting it in the machine, well... \$\endgroup\$
    – user173292
    Commented Oct 30, 2020 at 19:38
  • \$\begingroup\$ This is kind of what I was thinking but I wanted to confirm it. I am satisfied with these responses. Would someone like to post one as an answer? \$\endgroup\$
    – Joshua
    Commented Oct 30, 2020 at 19:48
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    \$\begingroup\$ So I discovered something: There is a filter called "Features" with the option called "Pick & Place". The pictures aren't reliable to show the plastic hats. digikey.com/en/products/filter/… \$\endgroup\$
    – Joshua
    Commented Nov 2, 2020 at 13:15

2 Answers 2

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Exactly what a pick and place machine needs depends on the particular machine, but generally at a very minimum three things are required.

  1. The component must be upright and sitting on a flat surface.
  2. The component must have a flat location roughly in the center of the top which can be used to pick it up with a vacuum nozzle.
  3. The machine must know what components it can find where.

Reels tubes or trays ensure that the components are presented to the machine in a known position and orientation. Stickers or caps allow the vacuum pickup tool to grab components that would not otherwise be friendly to such pickup.

So yes if you want to make stuff easy for your assembly contractor you want to choose components that are packaged in a way that suits pick and place machines. A bag of components with no picking surface is not automation friendly.

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Nowadays, it's very common to have SMD headers on tape and reel and with cap.

And that's what you need to buy if you want to be, not only pick and place friendly, but also friendly with the assembly workers. If you give them a trail or a tube, they can use it. But it's much more convenient for them if it's on tape and reel. Or at least on a tape (they can put the tape on a reel themselves). Then they can put the reel on the machine next to the other reels and assemble several components at once.

If there is no cap, they will probably have to use a separate machine just for this part or put them on the PCB manually (I don't know what they do exactly in this case).

If it's in a bag, they may just put them on your PCB by hand. And it will take more time and patience than with THT headers. They can also put them on a tray to serve the pick and place machine. But they will do this by hand anyway. it's an extra work for them. If there are more than 100 pieces to place in all, it doesn't make any sens.

Selling SMD components in bags is only useful for manual repair purpose. But it's possible that DigiKey doesn't have them on tape at all.

These things are often produced on order. If you need a large quantity (more than 500 pcs) you should find a specialized SMD header supplier. They will charge $100 or so for the tape. They don't charge for the caps, but you must make sure you mention the cap in your order. For large quantities, it will cost you much less than on DigiKey.

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