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I've got a project BOM costed out and I know my PCB costs. Without sending my project out for quote I'd like to be able to estimate the assembly cost by number of SMT components placed and the number of through holes (for connectors) requiring hand soldering. Assume these are assembled in the US. Assume I know the fixed costs for stencils, pick and place programming, etc.

Anybody have some ballpark figures which might help here?

Jason
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3 Answers3

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Won't fit in a comment field, so:

Note that you say "assembled in the US" - but this would apply only if expressly stipulated, as many companies with a US front end use Asian assembly or Indian or ... . I can recommend a well priced and highly competent and conscientious assembler in Serbia and can suggest a SD, CA company who assembles in all of USA, mainland China and Taiwan.

Very much comment only:

US: $More than China to $Much more than China.
Use following as a very rough guide only.

China:

Reasonable rule of thumb is 1/3 cent US ($US0.00333 cents US) per pad or termination for SMD. Through hole fits inside that cost as long as percent through hole termination points is small compared to SMD termination points.

The above "formula" just happens to come out very roughly right in many smaller cases. It is not a true reflection of costs in extreme cases. eg 2 terminal devices such as capacitors and resistors would be costed at 2 x 0.33 cents = 2/3 cents each. An 0805 1% metal film resistor costs somewhere around 0.1 cent in manufacturing volumes so the assembly cost swamps it. Whereas an eg SOIC14 pkg would cost at 14/3 ~= 5 cents and a SOIC8 at 8/3 ~= 3 cents whereas an eg TQFP44 would cost at 44/3 ~= 15 cents. The resistor install cost may be able to be worked on and the TQFP cost, as some aspects of pick and place costings scale approximately linearly with pin count and/or package size and others are very non linear with size.

When quoted for Taiwanese manufacture via a local NZ middleman who claimed a modest markup % on costs I have had quotes for many times the cost of what can be achieved directly in mainland China.

Russell McMahon
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  • Thanks! This is very helpful. I just need to figure out what multiplier to use to get from China pricing to US pricing. I am doing low volume runs (50-100) so I would guess that the savings from Chinese assembly would not be very significant (if any at all). So, I can be somewhat confident that my boards are assembled here in the US. – Jason Apr 25 '12 at 10:50
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    I'm not sure I agree with the cost per pin calculation. The cost of placing a 6 pin SOT23-6 is the same as placing a TSSOP-16. IIRC we calculated with ~2 eurocent per SMT part. But assembly cost is indeed many times the part's cost for resistors or capacitors. – Federico Russo Apr 25 '12 at 10:54
  • @FedericoRusso - You are welcome not to agree - but you'd be disagreeing with Chinese manufacturers and not with me. This was one way that costs were calculated for real products in some cases. Elsewhere in China the basis for costing was not stated but the end priced was very close to what this yields. – Russell McMahon Apr 25 '12 at 12:14
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    @Jason - great care! For small runs (eg 50-100) the cost can be and probably will be much higher. If you Gargoyle for: PCBA manufacture USA or PCBA assembly USA you will find many people offering services. I tried a 1000 run costing on one site for 1000 boards on a PCB that costs a few 10's of cents to make in China (manufacturing cost only) in 10,000 volume and the price was about 2 UK pounds !!! - maybe 5-15 times as high !!! – Russell McMahon Apr 25 '12 at 12:18
  • @RussellMcMahon Curious why it would be much higher if you factored out the static fees (setup, programming, etc). The pick and place operates at the same rate (assuming low and high volume processed on same machine). – Jason Apr 25 '12 at 18:57
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    @Jason - Minimum official monthly labour rate in China is 2000 RMB or about $US350. Most people work 6 days/week for that and longish hours. Some get paid much less than official rate. Say 6/7 x 30 days x 10 hours =~ 257 hours. That's under $US1.50/hour. In US the labour rate must come from somewhere regardless of pick and place costs. Basic plastic molding in US is about 2 x China price (varies). Much same arguments re assembly apply. – Russell McMahon Apr 25 '12 at 19:09
  • @RussellMcMahon Oh, I completely understand the labor issue. I am speaking only of US assembly in this instance. – Jason Apr 25 '12 at 21:32
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    @RussellMcMahon "many companies with a US front end use Asian assembly or Indian or ... " I guess you mean India is also used as a manufacturing destination. I am from India, I was thinking of getting my assembly job done from China, but reading this gives me hope that I can get it made in India itself at China comparable rates/specs. Could you point me to some Indian assembly service providers you know of? Its all SMT. One 0.5mm pitch QFN and 0603 passives. Rest all are TQFPs, SOIC and large SMD packages. – Dojo Aug 01 '16 at 17:51
  • @Dojo I do not know specific Indian PCB manufacturers. We have people here (in New Zealand) who have PCB batches produced in India or China depending on requirement. Many Indian companies use PCBs and some would no doubt be willing to advise a name. | One company that does its own PCB assembly and MAY make their own PCBs (but will know who does regardless) is KHMDL = Karnataka Hybrid Micro Devices. ttp://www.khmdl.com/. As well as much else, they make electronic product for the auto industry and armed forces and Indian space program - so should have a good feel for quality. I have no .... – Russell McMahon Aug 02 '16 at 14:02
  • ... association with KHMDL apart from having had a friend work there some while ago. For interest - where are you located. – Russell McMahon Aug 02 '16 at 14:03
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    I am located in Mumbai, India. Actually, we have a few assembly houses here, but I was of the opinion that sourcing everything from China would work out better as the components anyway come from there. Plus, the PCBA house (EMS) has certain requirement for component packaging (tape, tray) and you have to account for wastage and deal with MOQ from the component supplier etc. Plus, the EMS could leverage on its inventory on common components and cut costs. Well that's what I thought... – Dojo Aug 03 '16 at 17:00
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    I have requested some quotes but so far I am being quoted 2x to 4x the price for the components (when compared with rates from Shenzhen/HK market not Digikey). Also, much of the cost optimization comes from being able to pick the cheapest component variant from 100s of variants available in Shenzhen market. But the EMS will insist on an exact part number or will suggest a part number and freeze that. But usually, you'd like to say "this is the component I don't care about temperature range, RoHS etc., buy the cheapest variant you can find at time of buying". – Dojo Aug 03 '16 at 17:13
  • @Dojo Where are you getting the assembly quotes from - India or China or ...? I'll refer this discussionm offlist to a friend in Mumbai who may or may not wish to comment. [I visited Mumbai for a few days in 2014 as part of a 3 week visit to India (my wife was working in Pune). I hope to revisit India but may never do so. tbd]. – Russell McMahon Aug 04 '16 at 01:52
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    @Dojo Jumping in because Russell pinged me. My observations on assembly in / around Mumbai are thus:

    1. SMT parts, 2x to 8x of Shenzen pricing.

    2. Through-hole parts, 1x (common parts) to 10x (MOSFETs, static sensitive low volume parts).

    3. Low volume (100 to 1000 boards) pick&place assembly from a Gujarat based assembler I use: 2x Shenzen pricing even after including shipping. Customs dudty balances it out though.

    4. Bed of nails / probe testing: 8x to 20x China board house pricing.

     – Anindo Ghosh Aug 04 '16 at 04:41
  • @RussellMcMahon With reference to your info about friends getting boards assembled in India:

    If you want your designs to retain some semblance of confidentiality, get them made in India. Friends I know in Australia, for instance, get their "high intellectual property value" top secret devices assembled in India, and the rest of their device assembled in China.

    Quality stats (last 4 years) on SMD boards when not opting for 100% testing, China = 6% failed boards, India = 8% failed boards.

     – Anindo Ghosh Aug 04 '16 at 04:43
  • @RussellMcMahon Those quotes are from China. Haven't negotiated yet. Thanks for referring Anindo! – Dojo Aug 04 '16 at 19:02
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    @AnindoGhosh Thanks for your insights. Does your Indian EMS ask you for reels or are they okay with cut tapes without reel? How about tray packaging? How much wastage do you plan for? As in if you want to assemble x number of boards do you order parts for 1.05x boards or 1.1x? What's the multiplier? – Dojo Aug 04 '16 at 19:22
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    @Dojo Reels or trays, not cut tapes. Also, they pretty much lose interest unless they are also contracted to source most parts. On wastage, note my previous comment: 8% boards fail on average as per stats of one of my clients. Personal experience, closer to 15% bad boards. – Anindo Ghosh Aug 05 '16 at 04:48
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    @AnindoGhosh "they pretty much lose interest unless they are also contracted to source most parts" Yes, I felt like that too. For some reason they shy away from quoting the actual assembly amount under that heading and instead try to shift some of that cost to components. I think another reason they want to procure components themselves is because its less friction that way. If customer supplies parts they have to spend time educating the customer about how they want the parts, wastage, etc. – Dojo Aug 05 '16 at 15:03
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We usually have 100 units assembled at a time. I usually have a 64 to 100-pin QFP, a few 8 to 20-pin SOIC chips, and many 0805 resistors and caps.

I estimate $0.07 to $0.08 per pin/pad. That usually gets me a ballpark figure of what the assembly houses will charge. This does not include the tooling and setup charges. They run between $200 and $500, depending on the assembly house.

Edit We use assembly houses in New England (USA).

Robert Deml
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    Are you saying that at $0.07 per pin pad a QFP would cost in the order of 64 x 7c = $4.48 in manufacturing costs? So a PCB with say 1 x 64 pin QFP, 3 x 16 pin SOIC (say) and 30 0805 components would cost around 7c x (64 + 3 x 16 + 30 x 2) = 7c x 172 ~~= $12 – Russell McMahon Feb 01 '14 at 14:13
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    Don't forget all the 2-pin caps and resistors. Yes, each pin is roughly 7 cents in assembly costs. If you find something cheaper, post it here! – Robert Deml Feb 02 '14 at 01:03
  • @Robert https://jlcpcb.com/smt-assembly is $.0015 a joint with a $7 startup, but $3 per part that isn't in their 'basic' library – HilarieAK Jun 06 '20 at 13:24
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There is a huge assumption that your design is even manufacturable, or that it will be possible to get high yields. QTA shops who build prototype qty's less than $5K worth need to assess all your DFT, DFM errors and assess the risks of fallout from solderability to testability. Learning curve rejections and rework costs can well exceed the BOM cost in 1st run prototypes and the NRE for screens, machine setup, ATE fixtures and process design is strongly dependant on the complexity of the design and ability for DFT to do fault isolation quickly. i.e. self test vs ICT vs FT etc. Don't be too quick to assume the cheap cost unless you can commit and prepay volumes or take a risk on low cost & cross your fingers on yield. Either they need to be desperate for business or you are willing to take huge risks on field failures.

Tony Stewart EE75
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