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The per-PCB cost of manufacturing a small number of PCB is 10 times or more compared to the per-PCB cost of manufacturing a large number of PCBs.

So what is it exactly that adds to the cost?

People say there is setup cost or initial cost, what is it exactly? What steps in manufacturing need a special setup and cost this much?

I know there is printing of transparent film, but is it that costly?

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    \$\begingroup\$ It's not only 'hardware' reasons but also the cost of billing, administration, packaging etc. \$\endgroup\$ Dec 17, 2020 at 9:17
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    \$\begingroup\$ Classic costing scenarios. Fixed_costs / N plus variable costs per board. Admin, materials handling, file setups, machine setups, process setups (drill, etch, plate, mill, cut, ...) product handling, batching, QC. Where costs are competitive across multiple suppliers you will see optimisation of process with costs reflecting reality. \$\endgroup\$
    – Russell McMahon
    Dec 17, 2020 at 9:43
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    \$\begingroup\$ Also the PCB's are made on panels. Sometimes if they use a whole panel, they have to charge you more. I have had extras shipped to me (ordered 5 received 7). I assume the reason for this was that 7 fit on the panel, so they sent me 7. \$\endgroup\$
    – mkeith
    Dec 17, 2020 at 9:53
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    \$\begingroup\$ @mkeith: I had exactly that happen to me with the last batch of (small) PCBs I had made. It was cheaper to order 10 than to order the 8 I needed - and then they delivered 11, presumably because they filled the panel and sent me all of them rather than throwing away the extra. \$\endgroup\$
    – JRE
    Dec 17, 2020 at 10:20
  • \$\begingroup\$ Setup cost means things like making templates for the machines to use. They aren't like printers where the head goes back and forth and sprays ink in the right places - they're more like stencil machines that spray ink everywhere and the stencil gets in the way of where the ink isn't supposed to be. I think. \$\endgroup\$
    – user253751
    Dec 17, 2020 at 17:24

3 Answers 3

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Firstly the manufacturer needs to check your uploaded board for any irregularities. This is done by hand by engineers, so will cost a fair bit. If it is checked, the manufacturer needs to send your uploaded board to the place where production happens. Each batch of boards all need to be tracked, need their own place in the chemical baths, and need their own setups for the drilling and milling machines. I can imagine swapping batches takes longer than continuing to the next board, so that adds to "initial costs". At last you have packaging, individual packaging is a bit more expensive (per board) than packaging large batches.

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    \$\begingroup\$ Exactly! Someone produces 10000 boards: cool, your whole large panels that go through your machinery are the same thing, so you produce that, and do exactly the same for all the 10000 boards; test them, cut or break them from the panel, inspect them, put them in a box and ship them to your customer. If per panel, there's 100 customers, you test them, break them, sort them (manually!) into the individual orders, inspect them, put them into 100 different boxes and ship them. That costs time of someone on a factory line,AND you have to deal with 100 different customers, not all of which are nice. \$\endgroup\$ Dec 17, 2020 at 9:34
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    \$\begingroup\$ cheap international small packages get lost say, X % of the time, whereas expensive, crate-sized shipping to other factories gets lost (X/10) % of the time, so there's the added 9X/10 % you need to produce twice, and deal with dissatisfied customers. \$\endgroup\$ Dec 17, 2020 at 9:38
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    \$\begingroup\$ @MarcusMüller But wouldnt the bigger package represent a bigger loss? It is lost less frequently but is more expensive when that happens. I think you are right in general but the difference isnt 9X/10 %. \$\endgroup\$
    – Matt
    Dec 17, 2020 at 14:32
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    \$\begingroup\$ Why do manufacturers seem to insist on doing that kind of checking, instead of giving an option to work on a "your design rule violations, your yield problems" basis? \$\endgroup\$ Dec 17, 2020 at 19:41
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    \$\begingroup\$ @rackandboneman probably customer service. A lot of people do make mistakes, and it is important to translate “what the customer says he wants” to “what the customer probably wants”. If they would not, maybe 25% of people would be dissatisfied with the outcome of their PCB and never come back. \$\endgroup\$
    – Ananas_hoi
    Dec 17, 2020 at 19:45
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Your questions is somewhat vague. What is "small number"? What is "large number"? Making onesies is always going to be expensive, but when using PCB batching services at least you're not paying fixed upfront costs. Typically you are charged per in² of PCB space, with some extra for premium features like more copper, finish, etc.

However, to contrast really-low-volume (onesies) to really-high-volume (millions) you need to consider that there are different manufacturing techniques as well - where the board is punched, not drilled, and is made of phenolic resin, not fiberglass. This answer explains it fairly well.

This technique is specifically made for very high-volume production, and you just cannot use it for onesies.

David vs Goliath rant

On a somewhat related note, you may have noticed that, if you are small electronics manufacturer, on several ways you just can't compete with the big guys. Newcomers aren't welcome: they don't have the resources to set up automatic assembly lines, to use the really-high-volume PCB production processes, to twist the hands of overseas slave manufacturing, or even patent their work (with a single patent ~€10k, and that's for EU only; don't get me started if your gizmo has radio and needs FCC testing in the US).

OK, so you resign to making small batches of niche products, in this case likely the expensive PCBs may not be your biggest gripe. What startled me sometime ago was how costly custom plastic enclosures are. If you can fit your product into a standard box with drilled holes, then you're good to go, even though you need to tailor your PCBs to the existing enclosure. Big guys aren't constrained to that, since the $5k cost for a mold matrix is nothing to them. And they exploit that, because consumers value custom and sleek enclosures, they are viewed as "professional".

All in all, the industry begs for disruption, but I would not start with the PCB side of it.

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    \$\begingroup\$ The mold pricing is a really interesting use case for short-run 3D printed injection molds. There are high-temp plastics that could allow for a few hundred shots of ABS or GF30-PA6. \$\endgroup\$ Dec 17, 2020 at 23:14
  • \$\begingroup\$ Case design is really hard, and a much less standardised process than PCB manufacture. For a product, it's also a significant differentiator. I've had luck with batch 3D printing services for quantities under 500 or so, but there's a lot of back and forth with designers and manufacturers. \$\endgroup\$
    – awjlogan
    Dec 18, 2020 at 14:26
  • \$\begingroup\$ Re patents - getting them is one thing, enforcing them is quite another..! \$\endgroup\$
    – awjlogan
    Dec 18, 2020 at 14:26
  • \$\begingroup\$ @anrieff Problem you mentioning is what really got me into searching what really makes small quantity costly I think high initial cost and costly of trial and error is what making hardware business so slow and lack the level and scope of creativity Making iteration cost lower will really enable to create a solution for even small problems (which liberty only software has right now) \$\endgroup\$ Dec 19, 2020 at 12:42
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Even if you consider logistics alone, that custom PCB you want in a single-digit quantity is a separate product. It has to be produced, tested, stored, shipped and billed separately from other products, otherwise you will not get what you ordered. At every step there will be some fixed costs which would not apply if the factory had to produce another 10 pieces of an existing PCB.

If you produce a million of PCBs, you can set up an automated testing stand and a packaging robot. The 10 PCBs you ordered will certainly require human involvement.

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