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What would be the average speed (an experienced) person would assemble surface mount components on to a PCB? Assuming they have desk that is correctly set up (pick and place station) and the PCB has solder paste already applied.

Reason for the question:

Pick and place machines talk about components per hour (CPM) speed, interested to know how to compare this against a person. Looking into doing small runs (100 units) of a product, need to determine if I hire staff or purchase a small scale pick and place machine instead.

I know Sparkfun say they do this sort of work by hand, but I have a part count of 90!

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  • \$\begingroup\$ Some of the things to think about are providing the reels of parts to the assembler or loading them on the machine, visual que-carding the reference designators if doing it by hand, number of same value parts, if they can work on a whole panel at once, do all the 10k resistors on all of them, then the next part, etc. \$\endgroup\$ Feb 7 '11 at 8:02
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When soldering is done by hand there are lots of aspects that factor into how fast it can be done. Here are the largest factors for me when I am soldering:

  1. The pitch of the components. I have this cover both IC pitch and 2 pin size. The smaller they are the slower the human has to go to get it set properly.
  2. Through Hole components or SMD or both? Through hole components will actually take a lot more time to solder in my experience.
  3. How closely spaced the components are. Humans will always make mistakes and the closer the parts are together the harder it will be to fix them. Also the closer they are together the more likely a slip of the hand will cause another component to get hit and have to be fixed.
  4. How organized the parts and documents of assembly are. This one is pretty clear, if it is hard to figure what to put where it is going to take longer.

In general though, I would say it takes me about 45 seconds per part to place the parts on the board. The board can then be baking while more boards are assembled.

Where you have to be careful in time estimating is the time it will take to check for shorts and fix them. There will be errors, maybe just a couple out of the whole batch, but there will need to be more testing time when soldered by hand.

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Small runs like that are best sub-contracted. ASK Technology is a company I use.

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Agree with Leon, for this number of units.

Depending on the product and margins, it can still be economical to contract out at 1000+. The big contract manufacture companies (who generally also manufacture PCB's) can source your components at cheaper prices than you. We've even had them suggest changes that can cut costs from a product.

You agree prices at various price breaks and then place orders when you want. If you want, they'll even conduct the required tests, box-up and ship products straight to customers.

This all obviously has associated costs, but when you factor in the time for procurement, managing the manufacturing, testing and logistics and delivery, you'll struggle to come close to their prices. That is what these companies specialise in after all!

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  • \$\begingroup\$ You raise some good points, starting to think that outsourcing is the right answer \$\endgroup\$
    – oden
    Feb 7 '11 at 0:08
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I've had a little job at an internship of soldering 250 small boards. It consisted of about 3 resistors, 1 SOT23, 1 chip and 1 capacitor (all SMD). It took a total of about 3 work days (x7 hours) to assemble them. Doing it by a company was expensive (very small run - only 1500 components) and we were interns, so you know how things work out.

That was about 12 boards per hour, but I am not an incredible good/fast solderer either. So expect 45 - 1 minute per component. Note that the chip was only a 6 pin device.

Unless you have a board that consists of 25x resistors of the same value right next to each other, it sounds that 9000 components is going to take you at least 10 workdays.

I can hardly imagine that sparkfun does their work by hand. It only is worth it in China when loans are a few dollars per hour. If you need to pay someone in a company environment and costs $10 - $15 per hour (which is cheap I suppose), that's still 15 - 20cts per component added.

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  • \$\begingroup\$ Were you using solder paste? That seems very slow. I've assembled boards approximately five times more complex, at about that same rate. \$\endgroup\$
    – markrages
    Feb 6 '11 at 19:46
  • \$\begingroup\$ Do they really use manual soldering for fine SMD work in China? The errors introduced in manual soldering must make it more efficient to use pick-and-place? \$\endgroup\$
    – Tim
    Feb 7 '11 at 16:47
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    \$\begingroup\$ Manual soldering. We don't have any machinery involved other than our hands and a pincet. Yes it may seem long and slow, but it were very small boards. I just want to make clear that if you're doing manual production, it's a very tedious job and something to seriously doubt if you really want to go through it. If you lose a few days on it, it could have spent making money instead. \$\endgroup\$
    – Hans
    Feb 7 '11 at 19:43
  • \$\begingroup\$ But how much money could it cost you if there is a design fault and you moved into high volume production before it was discovered? I have had this happen to me before and hand soldered 2k units, not only did it take along time and cost more in additional parts but the product looked like crap and I had to deal with a recall issue. \$\endgroup\$
    – oden
    Feb 9 '11 at 3:26
  • \$\begingroup\$ For short runs, setting up the machine (loading the part spools, verifying/adjusting the device coordinates, handling exceptions) could eat up quite a bit of time. In my own experience, our assembly vendor did small (~10 boards or less) runs by hand. Separately, I've cracked open various no-name $0-after-rebate electronics, and have seen a wide variety of solder quality. I've even seen SMD's that looked like they were hand soldered with irons (not paste/reflow)... \$\endgroup\$
    – Toybuilder
    Jun 20 '11 at 17:38

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