Author Topic: General PCB Manufacturing Pros and Cons  (Read 8435 times)

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Offline ataradov

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Re: General PCB Manufacturing Pros and Cons
« Reply #50 on: August 12, 2017, 11:37:29 AM »
They just want to pad the price. In the end PCBWay is cheaper than AllPcb all around. I fell like they just want to convert AllPcb into a premium service.
Alex
 

Online blueskull

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Re: General PCB Manufacturing Pros and Cons
« Reply #51 on: August 12, 2017, 11:42:54 AM »
New Allpcb.com service sounds great except they they emphasise speed, and for some bizarre reason they charge $8.695 for each BGA part you've got on the board.

Even if you don't order assembly service?

It's common in China that they charge you not only based on their cost, but also on your estimated profit from their service. Basically more BGA means higher tech, and higher tech means more profit.
By this way, they can offer lower cost to low tech DIYers to spread their name, and recoup the cost from established high tech corporate customers.
The same is for why they charge extra for combined designs in a panel.

For the controlled impedance, there's actually a physical cost. Controlled impedance means the PCB side of the copper (bonding line) must be very smooth to not to introduce extra capacitance caused by rough (increased surface area) surface, and hence controlling impedance.
These boards have an additional process, that is to polish the surface for electroplating before carbon deposition and electroplating of copper, hence the extra cost.
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Offline evb149

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Re: General PCB Manufacturing Pros and Cons
« Reply #52 on: August 12, 2017, 01:05:51 PM »
blueskull may be right about this being purely rent-seeking "market segmentation" predatory pricing because there aren't many good alternative vendors.  But it may be as suggested that there is ZERO technical justification for the cost and they just do it because they can get away with it.  The fact that they pick not only "costs extra for BGA" but ALSO "costs extra for EACH BGA" on the same PCB is really not sensible when they are not doing assembly.

On the other hand there are some POTENTIALLY good reasons they or SOMEONE could charge a modest amount extra for (relative to the most basic possible 2L PCBs).  I'd actually be happy to pay a MODEST (speaking as a hobbyist) extra cost for a higher level service if it offered many or all of the following features which are actually relevant for many (most) but not all BGA designs:

* ENIG finish.  Because planarity and ROHS solder being better to use for BGAs and SMT even for hobbyists because of better (less) flow characteristics in reflow which tends to help SMDs stay in place despite a poor DIY reflow process.

* 8mil hole / 18 mil pad mechanically drilled vias.  Usually 8mil/18mil is the only hope for a great many even quite low density (1mm / 0.8mm pitch etc.) BGA breakouts if using separate vias and no HDI processes.  Even with such small mechanically drilled holes it is still impossible to break out many low to medium-low density BGAs with full arrays as most are.

* Properly plugged and plated over "via in pad" processing which is especially relevant for any CSP or BGA packages that are low to medium low or more density.  There is literally no alternative to via in pad with proper pad plugging, plating, and planarization for MOST BGAs and basically everything but the most simple CSPs needing breakouts.

* Obviously offering low cost laser drilled microvias, blind and buried vias as well as via in planarized plated over pad would be IDEAL for almost any BGA package even higher density CSP ones.  So it would be quite attractive if manufacturers could offer such services for low enough costs to be relevant to hobbyists.  There are many CPU and SOC and FPGA and sensor and similar projects I would make as a hobbyisst if such PCBA technology was affordable to prototype and make in low quantities.  But even without full HDI processing at least with the above options you could access several low or medium low density BGAs but still probably be excluded from the possibility of MOST modern CSP BGAs without HDI / micro vias.

* Narrower minimum solder mask clearances from non-solder-mask-defined pads.  Also narrow minimum solder mask minimum web diameters between pads.  Almost any fine pitch BGA / CSP BGA even ones with only 4 pins and certainly ones with 9-dozens+ will stipulate in the recommended layout application notes that you should be able to have solder mask still present in between the BGA or CSP BGA ball pads so you will less likely have solder bridging.  The 4 mil minimum pad to mask edge clearances that are offered at low costs aren't even good enough to allow solder mask between many 0.5mm pitch QFN / QFP and similar low density SMD parts.  BGA / CSP usually impossible.

* Allowance for 3.5mil or 4mil minimum diameter track and gap sizes because it is necessary to allow running one or more tracks between CSP / fine pitch BGA balls for the recommended / necessary breakout routing patterns for the parts and for proper neck down entry to small CSP pads etc.

Those are characteristics of what I would call "ordinary" SMD manufacturing capability that properly supports CSP or fine pitch BGA packages.  That and inexpensive PCBS with 6 layers minimum and affordable also for 8 or 10 layers.
Anything much less and you will have only the most minimal percentage of CSP / fine pitch BGA parts usuable on a 4L PCB with the unsuitable 0.3mm via hole / 4mil solder mask to pad clearances / non plugged via type of design rules you see from low cost services.

So actually for a proper manufacturing process I would not mind some extra cost but when you start to see $2000-$5000 costs for just a few prototype PCBS like many companies pay for quantity 5-10 boards with 8-10 layers, CSP BGAs, etc. then it completely excludes almost every maker / hobbyist and a lot of small businesses also that can't spend thousands to make a few prototypes just for the satisfaction of making a modern and interesting circuit design.

Every hobbyist now is used to using PCBS like RaspberryPi, BeagleBone, etc. but mostly nobody besides big companies could afford to make similar products with DRAM, ARM-A CSP BGA SOCs, fine pitch FPGAs, etc. because of the PCB costs and also to some extent assembly costs / difficulties.


Even if you don't order assembly service?
Yep. Check out their new ordering page - there is a field at the bottom where you're supposed to type in number of BGAs in your design. I wonder what they were thinking when they've introduced this surcharge - I can't think of any reason to use 6-layer boards other than breaking out large BGAs...
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #53 on: August 12, 2017, 01:07:32 PM »
They just want to pad the price. In the end PCBWay is cheaper than AllPcb all around. I fell like they just want to convert AllPcb into a premium service.
Not for 6-layer boards. Even with added costs of 4 BGAs 0.125/0.125/0.25 mm boards with 50 Ohm CI (minimum for 0.8 mm BGAs like DDR2/3/3L) are cheaper in allpcb. PCBWay pricing for that kind of board is weird - price with CI is less that without CI :o
 

Offline ataradov

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Re: General PCB Manufacturing Pros and Cons
« Reply #54 on: August 12, 2017, 01:14:58 PM »
Not for 6-layer boards.
Don't judge allpcb price by the instant quote. They will bump it by a random amount after you already paid, and ask you to pay more. At least that's what they did to me on a pretty simple board.

And oh yeah, refunds don't go back to PayPal, they go towards store credit.
Alex
 

Offline evb149

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Re: General PCB Manufacturing Pros and Cons
« Reply #55 on: August 12, 2017, 01:16:16 PM »
Yeah controlled impedance is a good feature.  And to the extent that it incurs real extra costs somewhat in fabrication but also in testing (TDR, certificate, rejection and remanufacture of PCBs out of specification) then I expect some cost addition for it.  But to suddenly increase the PCB cost by 30x or whatever just because of picking a copuple of options other than the lowest cost ones is extreme and unreasonable pricing.

For many designs I'd be happy enough with "controlled dielectric / specified stackup" service even without guaranteed per batch tested and tuned controlled impedance.

They could just offer a few standard PCB options, FR4 2L 1.6mm or 0.8mm, FR4 4L 1.6mm or 0.8mm, FR4 6L 1.6mm or 1mm-0.8mm whatever is sensible, and then for the 4L / 6L options maybe a couple of different common stackup options for core and prepreg types and spacings.

Then if they just said that you pick whichever of those few choices you want then you will know exactly the PCB material stackup, thicknesses, dielectric constants, solder mask thickness / type, etc.  And they could just send one or two sample production boards of test coupons in such stackups per year to be TDR tested to characterize the impedance.  Then based on that they can just say for our standard stackup #3 typical L1 to L2 microstrip 50 ohm line is 12mil wide, L2 to L3 stripline is 7 mil wide 50 ohms, etc. and assume that will be true to within maybe +/- 25% without actual per-design analysis and testing.  If you need better then you can pay some more for per-design controlled impedance.

But if someone offers reasonable for DIY cost controlled impedance with testing and CAM to make the impedance come out right so much the better.  It is about time.


For the controlled impedance, there's actually a physical cost. Controlled impedance means the PCB side of the copper (bonding line) must be very smooth to not to introduce extra capacitance caused by rough (increased surface area) surface, and hence controlling impedance.
These boards have an additional process, that is to polish the surface for electroplating before carbon deposition and electroplating of copper, hence the extra cost.
 
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Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #56 on: August 12, 2017, 01:47:27 PM »
Don't judge allpcb price by the instant quote. They will bump it by a random amount after you already paid, and ask you to pay more. At least that's what they did to me on a pretty simple board.
I used their service few times (admittedly before they've dumped subcontracting business and became a manufacturer), and what you're describing only happened once, and even then we quickly resolved situation to my satisfaction. So I can't say anything bad about them from my experience - other than they don't seem to support Gerber x2 format and work with older one.
« Last Edit: August 12, 2017, 01:51:29 PM by asmi »
 

Offline Kean

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Re: General PCB Manufacturing Pros and Cons
« Reply #57 on: August 12, 2017, 11:52:20 PM »
Additional cost per BGA could be related to e-testing.  They might have to use a higher spec flying probe machine for some BGA pad layouts.
That additional cost seems somewhat exhorbitant though.  I imagine they want to always cover costs (+ a good margin) on these more advanced designs ... while they still can.
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #58 on: August 13, 2017, 12:37:29 AM »
Additional cost per BGA could be related to e-testing.  They might have to use a higher spec flying probe machine for some BGA pad layouts.
In this case it would be a flat fee, and I would be OK with that (as long as it's reasonable). But per-package fee is something really weird.
 

Offline GreggD

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Re: General PCB Manufacturing Pros and Cons
« Reply #59 on: August 13, 2017, 01:17:08 AM »
Options for UL markings and certificate of conformance.
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #60 on: August 13, 2017, 02:10:39 AM »
It's common in China that they charge you not only based on their cost, but also on your estimated profit from their service. Basically more BGA means higher tech, and higher tech means more profit.
By this way, they can offer lower cost to low tech DIYers to spread their name, and recoup the cost from established high tech corporate customers.
Well my profit from my boards is zero. I'm totally willing to share that profit with them if they so desire. Damn, I can give them the whole 100% of that profit! :-DD
 

Online blueskull

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Re: General PCB Manufacturing Pros and Cons
« Reply #61 on: August 13, 2017, 05:32:33 AM »
It's common in China that they charge you not only based on their cost, but also on your estimated profit from their service. Basically more BGA means higher tech, and higher tech means more profit.
By this way, they can offer lower cost to low tech DIYers to spread their name, and recoup the cost from established high tech corporate customers.
Well my profit from my boards is zero. I'm totally willing to share that profit with them if they so desire. Damn, I can give them the whole 100% of that profit! :-DD

For that case, PCBWay has an sponsorship discounting. Basically you sign an agreement with them stating your PCB work is not funded, and you agree to provide them with a photo including your acknowledgement to their service and your final physical board. They can give you a heavy discount.

Check out here: https://www.pcbway.com/project/sponsor/

There are some really cool projects.
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Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #62 on: August 13, 2017, 01:15:24 PM »
For that case, PCBWay has an sponsorship discounting. Basically you sign an agreement with them stating your PCB work is not funded, and you agree to provide them with a photo including your acknowledgement to their service and your final physical board. They can give you a heavy discount.

Check out here: https://www.pcbway.com/project/sponsor/

There are some really cool projects.
I looked at that, and they seem to require photos of the project before getting sponsorship. But how am I supposed to have them, if I don't have the board?
 

Online blueskull

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Re: General PCB Manufacturing Pros and Cons
« Reply #63 on: August 13, 2017, 01:26:42 PM »
I looked at that, and they seem to require photos of the project before getting sponsorship. But how am I supposed to have them, if I don't have the board?

It requires a cover picture upfront, can be anything, not exactly the finished project.
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Online NorthGuy

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Re: General PCB Manufacturing Pros and Cons
« Reply #64 on: August 20, 2017, 02:15:55 PM »
I want to add my vote for more layers (6, may be even 8), better specs (4-5mil traces/8-10mil drills), ENIG. There's plenty of places where you can order low-end, but it is real hard to find a manufacturer for reasonably priced 6-layer boards with good specifications. Even if it's small and you only need one or two, you'll end up paying $300 or more. This is a huge room for price improvement here.
 
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Online blueskull

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Re: General PCB Manufacturing Pros and Cons
« Reply #65 on: August 20, 2017, 02:20:21 PM »
I want to add my vote for more layers (6, may be even 8), better specs (4-5mil traces/8-10mil drills), ENIG. There's plenty of places where you can order low-end, but it is real hard to find a manufacturer for reasonably priced 6-layer boards with good specifications. Even if it's small and you only need one or two, you'll end up paying $300 or more. This is a huge room for price improvement here.

WellPCB offers 1.2mm, 6L 6 mil drill with 3mil track/spacing and ENIG boards at $195/5pcs plus $2/pcs, for size of 50mm*50mm. They also offer ultra thin technology, down to 0.35mm/4L and 0.55mm/6L.
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Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #66 on: August 21, 2017, 12:14:05 PM »
I want to add my vote for more layers (6, may be even 8), better specs (4-5mil traces/8-10mil drills), ENIG. There's plenty of places where you can order low-end, but it is real hard to find a manufacturer for reasonably priced 6-layer boards with good specifications. Even if it's small and you only need one or two, you'll end up paying $300 or more. This is a huge room for price improvement here.
Allpcb now offers 5 6-layer boards 100x100 mm 0.125/0.125 mm trace/spacing 0.25 mm drill, 50 Ohm CI, ENIG for only $200. But they charge $8.695 per each BGA device you've got on the board ::) They also offer 4-layer boards with the same specs for $95.76.
So we're slowly getting to the point where 6 layer boards are a viable option for hobbyists. 4-layer board already are totally viable, especially if you can make do with "default" 0.15/0.15/0.3 process.
 
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Online mrpackethead

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Re: General PCB Manufacturing Pros and Cons
« Reply #67 on: August 21, 2017, 05:05:09 PM »
Been discussing this bga malarkey with them.. And they are are looking at it.
 

Online NorthGuy

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Re: General PCB Manufacturing Pros and Cons
« Reply #68 on: August 31, 2017, 01:11:13 PM »
WellPCB offers 1.2mm, 6L 6 mil drill with 3mil track/spacing and ENIG boards at $195/5pcs plus $2/pcs, for size of 50mm*50mm. They also offer ultra thin technology, down to 0.35mm/4L and 0.55mm/6L.

Thanks. These guys offer really good prices.

For some reason no one publish their stack-ups :(

Quote form is strange. If I select 3-4 mil option, the form says +10%, but price goes up dramatically. They also don't say what are the specs if you don't select "3-4 mil".

Will need to email them.

Allpcb now offers 5 6-layer boards 100x100 mm 0.125/0.125 mm trace/spacing 0.25 mm drill, 50 Ohm CI, ENIG for only $200. But they charge $8.695 per each BGA device you've got on the board ::) They also offer 4-layer boards with the same specs for $95.76.
So we're slowly getting to the point where 6 layer boards are a viable option for hobbyists. 4-layer board already are totally viable, especially if you can make do with "default" 0.15/0.15/0.3 process.

Thanks for that too. WellPCB looks more promising though. But devil is in the details :)

Perhaps prices are going improve soon!
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #69 on: August 31, 2017, 01:33:57 PM »
For some reason no one publish their stack-ups :(

Quote form is strange. If I select 3-4 mil option, the form says +10%, but price goes up dramatically. They also don't say what are the specs if you don't select "3-4 mil".

Will need to email them.
Their form is weird to say the least. For example, you can't select CI and 3-4 mil traces (wtf is that btw? is it 3 mil or 4 mil?) at the same time. If you will find out - please let me know. Also I wonder what would it cost to have a custom stackup, as all default stackups I've seen to far sucks for 50 Ohm traces unless you're OK with going to thinner PCB. And that is dangerous for big BGAs as they can easily crack if PCB is too "bendy".

Thanks for that too. WellPCB looks more promising though. But devil is in the details :)
And there are indeed "details". 4 times smaller area (I might suck at layout, but in my design just DC-DC converter to supply FPGA power takes up about 3x5 cm area), also standard TG-130 will not fare well under Lead-free reflow temperatures (PCBWay, for example automatically, upgrades board to TG150 for 4 layers and above).
Perhaps prices are going improve soon!
I can't wait for that to happen. But for now we're seem to be stuck with ~$300 per five 10x10 cm PCBs. PCBWay seems to offer no-cost custom stackup and via-in-a-pad options - at least their calculator says so, not sure if it's actually correct as it also shows non-CI boards much more expensive than CI ones, as well as 5x5 cm boards being twice the price of 10x10 cm ones, none of which makes any sense whatsoever. I kinda suspect that it's just broken for these kind of boards, but for now I'm trying my very best to stick to 4-layer boards to save money. I know there is PCBWay representative here on the forums, maybe he/she would be kind enough to shed some light on this madness.
« Last Edit: August 31, 2017, 01:35:30 PM by asmi »
 

Offline KL27x

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Re: General PCB Manufacturing Pros and Cons
« Reply #70 on: August 31, 2017, 01:50:24 PM »
Quote
Quote
Additional cost per BGA could be related to e-testing.  They might have to use a higher spec flying probe machine for some BGA pad layouts.



In this case it would be a flat fee, and I would be OK with that (as long as it's reasonable). But per-package fee is something really weird.

I don't see it this way. The prices they give aren't exact. Based on the same area of board, same minimum pitch, components, vias.... essentially every possible spec that can be input into a quote algorithm.... one customers board can be a lot less profitable than another, due to MORE of the board being minimum pitch and/or having more traces, overall.  Presence of BGA can potentially be closely associated with the manufacturing cost (lower yield). In fact, if looked at this way, it might be generous that there is a flat per-unit fee, rather than and exponential one.

So if presence of a BGA (statistically, on average) increases chance for failed board by 10% (on average), putting half a dozen of them on 1 board means they make and test twice as many boards as you order and end up throwing half of them away.

Personally, I try to make my board manufacturer-friendly. In case I repeat order a lot of them, I can ask for a new quote/discount. If you "abuse" the minimum clearances to get the tiniest board possible to save a few cents, you will save money in the short run, based on the flat-pricing model, but you wlll not be a favorite customer, lol.
« Last Edit: August 31, 2017, 02:09:45 PM by KL27x »
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #71 on: August 31, 2017, 02:04:07 PM »
I don't see it this way. The prices they give aren't exact. Based on the same area of board, same minimum pitch, components, vias.... essentially every possible spec that can be input into a quote algorithm.... one customers board can be a lot less profitable than another, due to MORE of the board being minimum pitch and/or having more traces, overall.  Presence of BGA can potentially be closely associated with the manufacturing cost (lower yield). In fact, if looked at this way, it might be generous that there is a flat per-unit fee, rather than and exponential one.
Why would you want a 6 layer board if not for BGAs? I just don't understand this.

If presence of a BGA increases chance for failed board by 10% (on average), putting half a dozen of them on 1 board means they make and test twice as many boards as you order and end up throwing half of them away.
Can you please provide your source for 10% data point? It seem weird to me as BGA pads are usually larger than some other parts' footprints (like 0.2x0.2 mm pads of BME280 sensor), yet they didn't change anything extra from me for that... It just doesn't add up.
The theory posted above (about ripping off "perceived profit" off customers) at least makes some sense, but I just don't see a relationship between amount of BGAs and "profitability"/"high-tech"-ness of the board. Afterall, most SoC boards usually only contain two or three BGAs (main one for the SoC itself + 1 or 2 DDR3 devices), and these boards are definitely "high-tech".
 

Offline KL27x

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Re: General PCB Manufacturing Pros and Cons
« Reply #72 on: August 31, 2017, 02:11:55 PM »
I am not sure what 6 layer issue is. I was only commenting on additional cost per BGA. Personally, every PCB I have ever seen with BGA on it, the density of components and microscopic caps/resistors is highly associated and localized around said BGA. To me, it seems logical that based on manufacturer's own statistics that each BGA could cost the manufacturer money/profit if they stick only with their "automatic quote machine," without exception.

The 10% is just theoretical. Pulled out of a hat for sake of argument.

In making my own boards, for instance, it is easily observable over time that yes, I can do 6/6 where absolutely necessary. But the more of the board I want to cover with this kind of pitch, and the larger the board, the more I can expect failure. One failure in a tight pitch area on a huge board still equals huge piece of garbage. Vs 1 mistake on panel of 10 smaller boards means 90% good boards.

If you order your boards on a panel, you will find that even large pitch very simple boards have a failure rate. This is a real cost in material and time and work.
« Last Edit: August 31, 2017, 02:20:49 PM by KL27x »
 

Offline asmi

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Re: General PCB Manufacturing Pros and Cons
« Reply #73 on: August 31, 2017, 02:19:37 PM »
I am not sure what 6 layer issue is. I was only commenting on additional cost per BGA. Personally, every PCB I have ever seen with BGA on it, the density of components and microscopic caps/resistors is highly associated and localized around said BGA. To me, it seems logical that based on manufacturer's own statistics that each BGA could cost the manufacturer money/profit if they stick only with their "automatic quote machine," without exception.

The 10% is just theoretical. Pulled out of a hat for sake of argument.
The "microscopic-ness" of caps for BGA decoupling is more related to BGA pitch than it is to amount of them. If they can't even reliably produce 0402 pads, they probably do not deserve to still be in business at this day and age.
But they can, and we all know that. Another curious thing - every other PCB fab I've ever used didn't not give a crap about what's actually on the board. allpcb is the first and only that I know if (so far) that does that. If this is caused by them having too many failures - I would probably serve myself well to steer clear of them and instead take my business to other fabs who are certain about their manufacturing abilities.
« Last Edit: August 31, 2017, 02:25:53 PM by asmi »
 

Offline KL27x

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Re: General PCB Manufacturing Pros and Cons
« Reply #74 on: August 31, 2017, 02:21:29 PM »
In making my own boards, for instance, it is easily observable over time that yes, I can do 6/6 where absolutely necessary. But the more of the board I want to cover with this kind of pitch, and the larger the board, the more I can expect failure. One failure in a tight pitch area on a huge board still equals huge piece of garbage. Vs 1 mistake on panel of 10 smaller boards means 90% good boards.

If you order your boards on a panel, you will find that even large pitch very simple boards have a failure rate. This is a real cost in material and time and work.

It's not as simple as a manufacturer can do up to X pitch or not. There's a curve and an associated cost. Period. It's not a matter of my process is more accurate, so I can do this 100%. They must dedicate more time, experienced workers, and loss in yield rate for tighter pitch boards with higher pad counts. And there is probably a fairly strong association to presence of BGA.

Just because one manufacturer has this extra charge and another does not, this does not mean one manufacturer is ripping you off. It means they use a different model to account for their actual costs, on average. You can game the system to find the best price; but if/when everyone does this and when BGA becomes a larger part of their business, everyone else will also start charging extra, or at least change their pricing model.
« Last Edit: August 31, 2017, 02:27:08 PM by KL27x »
 


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