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What is the difference between PCB fabrication and assembly? Some companies like Golden Phoenix list that based on the size of PCB, it outputs a quote.

Mine was 2.1 x 1.6 inch. It outputted 29 pieces for $100. So it means if I give them my schematic and PCB layout and pay them $100, I will get 29 pieces of production-ready PCBs ready to sell?

Now one company, EPS, lists fabrication and assembly differently. In assembly, it states I ought to provide the parts. In fabrication, anything but about parts is stated.

So what are these companies suggesting?

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    \$\begingroup\$ They don't need (or likely want) your schematic to fab the PCBs-- it's best to provide Gerber files, drill file(s) plus fab notes, to fully describe which layer is which, material, layer stackup and so on. \$\endgroup\$
    – Spehro Pefhany
    Commented May 23, 2014 at 12:44
  • \$\begingroup\$ @SpehroPefhany If i only gave them d PCB layout wouldn't that work. \$\endgroup\$
    – arjun
    Commented May 23, 2014 at 17:52
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    \$\begingroup\$ Maybe it would work- the PCB layout file is dependent on the software used, whereas Gerber RS-274X is a pretty much universally accepted means of transferring much of the information (along with drill files). If the PCB maker specifically says they will accept Altium or Eagle or whatever files from the software you are using (version too?), then it should work. You'll still have to supply some additional information in many cases to get exactly what you want. For commercial reasons (which may not apply to you), it's also not a great idea to distribute more IP than you have to to the factories. \$\endgroup\$
    – Spehro Pefhany
    Commented May 23, 2014 at 17:58
  • \$\begingroup\$ You raised a very imp point. About IP. How does an individual or company ensure their design is safe in the hands of M/F. Within the country it would be possible to make them sign NDA. but what about M/F based outside of your country. \$\endgroup\$
    – arjun
    Commented May 23, 2014 at 18:18
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    \$\begingroup\$ For ordinary boards, we don't worry about it too much (Gerbers can be created from a sample, and the layout is covered by copyright in about all countries). Military and space-related electronics require special considerations. A schematic allows someone to implement another embodiment of the same design, so it's actually a more sensitive document despite being more abstracted from manufacturing information. \$\endgroup\$
    – Spehro Pefhany
    Commented May 23, 2014 at 18:29

3 Answers 3

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In PCB world, "fabrication" refers to making the printed circuit board and nothing more. "Assembly" means soldering on all the parts.

So, in your example, $100 will get you 29 pieces of copper-clad FR4, with traces etched and holes drilled. It is up to you to solder on the resistors, capacitors, etc which you need.

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PCB Fabrication involves only manufacturing the board itself. No soldering being done.

PCB Assembly is the process of soldering components onto the board.

Simply said, fabrication is an easy process to quote price for, thus is often done automatically via a web form. Assembly requires much more thought put to the manufacturing process and so cannot be priced automatically (that is, accurately enough).

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    \$\begingroup\$ Also worth noting, that if you didn't design your PCB for manufacture, it will be much more expensive. \$\endgroup\$
    – Matt Young
    Commented May 23, 2014 at 12:45
  • \$\begingroup\$ Thnx for clearing dat form part. I wondered why wud PCB m/f be so low compared to d actual parts. Before this i was really excited about d cost! \$\endgroup\$
    – arjun
    Commented May 23, 2014 at 17:49
  • \$\begingroup\$ @MattYoung ought to start thinking about Finance. \$\endgroup\$
    – arjun
    Commented May 23, 2014 at 17:51
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    \$\begingroup\$ @arjun It's not all about finance, it's good engineering. \$\endgroup\$
    – Matt Young
    Commented May 23, 2014 at 18:22
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Dzarda has it right. The prototype-type PCB fabrication places will send you printed circuit boards, and that's it. These boards are suitable to test your circuit, and can be used for very small production runs if you have the ability to populate them. They can be used for HAND ASSEMBLY of your circuit. They will generally not be suitable for an automated assembly process. Thus, if you buy the PCBs and send them to an assembler, you will get charged for circuit components (with a handling fee tagged on, which can range from about 10% to silly levels), plus estimated technician time for hand assembly. You may also have NRE's tagged on -- a "non-repeating engineering" fee. This can actually be pretty reasonable, all things considered, especially if the company you're working with deals with non-domestic assemblers of good repute.

That said, to bring your product up to a manufacturable state for automated system, you might even find yourself paying MORE per PCB than you do at your prototype supplier-- sometimes just because your order comes in at less than the minimum price for PCBs. Also, pick-and-place assembly fee schedules can be surprisingly expensive for small production runs. Avoid doing anything silly, like mixing SMT and through hole parts, or having components on both sides, unless you're willing to pay for the adding processing.

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    \$\begingroup\$ This was very helpful. \$\endgroup\$
    – arjun
    Commented May 23, 2014 at 17:47

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