Why are castellations so expensive and are they really what i think they are?

[Refrigerator]

I need to order some boards that have castellations on both opposing edges but whenever i click the castellation option the price jumps through the roof.
For example if i go to JLCPCB and click on castellation option the price jumps from 2 bucks to over 40 
Same with any other PCB fab service i've checked, at least the ones that have the castellation option.
The only time such a price hike happens is if i choose the gold plating option, so do they gold plate castellations? Is that why the price goes up so much?
Personally i don't need gold plating because the castellations are for soldering so regular tin plating is fine. Can i just leave my vias and let them chop through them with their router? Will that work?

Also this is my first time ordering a PCB* so i'll include a pic of what the board looks like, please point out if you see anything obviously bad 
It's been updated since but i've not settled on a final version, the boards are 91x6mm and there are three in a set that assemble into one.
And i'm planning to use the extra 9mm to route traces between the boards and V-groove through the edge (if that's possible).
Sort of taking inspiration from one of Dave's old videos where he did the same for his panel of µCurrents for testing.

*normally i make my own but double sided boards are not my forte, especially not at this scale.

Ps: I can inlude more files of my boards, i just haven't yet because i don't want to litter the server with potentially unwanted files.

[T3sl4co1l]

They'll find them on review, regardless.  They'll... well, I don't know about JLC, but most will send an email confirming your intent.

And it's not like $40 is going to cost you your next yacht.

Typical failures are burrs left on the holes, and tearout of the plating.

If you're just doing a few and don't mind the time to clean up the burrs with a utility knife, yeah, no problem.  Maybe order a few extra in case the yield is low (tearout).

If you're doing production, pay for the quality assurance.

Tim

[Siwastaja]

$40 sounds normal for a cheap custom manufactured PCB with some special requirement, this size.

$20-30 would sound normal without the castellated edge.

The fact a fab might provide a special offer for $2, obviously at loss, is irrelevant. You can't count on finding such deals, especially if you have any even remotely "special" requirements.

[Refrigerator]

They'll find them on review, regardless.  They'll... well, I don't know about JLC, but most will send an email confirming your intent.

And it's not like $40 is going to cost you your next yacht.

Typical failures are burrs left on the holes, and tearout of the plating.

If you're just doing a few and don't mind the time to clean up the burrs with a utility knife, yeah, no problem.  Maybe order a few extra in case the yield is low (tearout).

If you're doing production, pay for the quality assurance.

Tim

I don't really care about the tearout, this is a group project for uni and me with my friend even considered just cutting the castellations ourselves. 
This won't cost me my next yacht but it might cost me my next DMM 
I'm leaning more towards V-grooving then, i can clean the edge myself so it's no big deal.
Now the question is can i V-groove? Aren't V-grooves set up for a whole panel?

[Refrigerator]

$40 sounds normal for a cheap custom manufactured PCB with some special requirement, this size.

$20-30 would sound normal without the castellated edge.

The fact a fab might provide a special offer for $2, obviously at loss, is irrelevant. You can't count on finding such deals, especially if you have any even remotely "special" requirements.

Yes the 2$ is a special deal for your first order + the cheapest and slowest shipping possible. We've checked all of the available PCB fabs and have settled on PCBWay, which is like ~27$ shipped.

Just kind of weird to me that i can buy an ESP32 that has many castellations on 3/4 edges for just a couple bucks, so i expected castellations to be cheaper 

Edit: wooo my 1000-th post 

[Feynman]

I would assume that there is in fact some special treatment explaining the increased price. Maybe it is just little things like a special router type or special routing speed for cutting through the holes. At the very least I would expect that the final inspection process is different, if you indicate that you have castellated holes in your design.

You can try to sneak in the castellated holes, of course. But there is risk of delay, because the manufacturer might put the job on hold in order to get confirmation that your data is right and cutting through vias is exactly what you want. Or the board just runs through the regular process and the castellations might end up with sharp and ugly edges or ripped out vias.

[ejeffrey]

You can't really compare the price structure for pooled prototypes with that for mass production.  The things that make pooled or small volume services more expensive are things that require more setup and review or make it harder to pool.  For mass production the NRE is usually insignificant and the drivers of cost are things that increase fab steps, use more materials, or slow down automated equipment.  Of course both have an element of what the market will bear: if you ask for a rare feature they may be able to charge considerably more than the extra production cost.

[cgroen]

.
Just kind of weird to me that i can buy an ESP32 that has many castellations on 3/4 edges for just a couple bucks, so i expected castellations to be cheaper 
.

What do you think the developers of the ESP32 paid for their first prototypes
I bet its different than what they paid for the next 20.000 boards

[Mechatrommer]

And it's not like $40 is going to cost you your next yacht.

This won't cost me my next yacht but it might cost me my next DMM 

with saved $30+ you can buy clone dremel and pack of cutting disc. i've made a sliding table for mine to cut straight on pcb, proved to be usefull everytime my pcb order arrived. i guesstimate it will be around 300 orders then i can buy a small yatch.

[Refrigerator]

Well i'd like to get this idea sorted out by monday. For now i've made another iteration, also inspired by one of Dave's old videos.
Does V-grooving count as a big extra step? Or am i just better off running a knife along the edge of my board?

I've included a screenshot of one of Dave's videos where he did exactly what i'm trying todo right here, that is horizontal routing and vertical V-groove through pads. And also a screenshot of an even older video where he did the same except no pads on the V-groove line.

Ps: i noticed that there's not much of a price difference between 10x10cm boards or smaller so i just crammed as much as i can fit in 10x10cm to maximise.

[Mechatrommer]

you've been given the advice to not use a hand knife, been there.

[Refrigerator]

you've been given the advice to not use a hand knife, been there.

Yeah it looks like i might need to just pull out my old dremel. I had actually forgotten that i have one 
But a knife does also work, it's just that it goes dull very quickly. And if there's anything more dangerous than a sharp knife, it's a dull knife.

[Siwastaja]

Just kind of weird to me that i can buy an ESP32 that has many castellations on 3/4 edges for just a couple bucks, so i expected castellations to be cheaper 

Obviously, it's produced in tens or hunderds of thousands...

[jmelson]

Is this the same as "mouse bites"?  That is just an area where they drill a bunch of closely-spaced holes and don't route that area apart from the panel.
Most PCB manufacturers have mouse bites and V-score available, and don't charge a lot for doing that, as it is done with the same gear as other processes.  The V-score is done with a different bit in the router, and they have to do both sides of the panel, so that ups the price just a fraction.
This does make the panel more fragile, so they have to handle it carefully so as not to break out the single boards.

Jon

[T3sl4co1l]

Mouse bites aren't plated.

Tim

[phil from seattle]

Yeah, I think castellation takes more steps so a higher cost is justified.  I do think some of the advanced services are priced to make up for the $2 pcb loss leader offers. It wouldn't surprise me if this is one.

[JLCPCB Official]

I need to order some boards that have castellations on both opposing edges but whenever i click the castellation option the price jumps through the roof.
For example if i go to JLCPCB and click on castellation option the price jumps from 2 bucks to over 40 
Same with any other PCB fab service i've checked, at least the ones that have the castellation option.
The only time such a price hike happens is if i choose the gold plating option, so do they gold plate castellations? Is that why the price goes up so much?
Personally i don't need gold plating because the castellations are for soldering so regular tin plating is fine. Can i just leave my vias and let them chop through them with their router? Will that work?

Also this is my first time ordering a PCB* so i'll include a pic of what the board looks like, please point out if you see anything obviously bad 
It's been updated since but i've not settled on a final version, the boards are 91x6mm and there are three in a set that assemble into one.
And i'm planning to use the extra 9mm to route traces between the boards and V-groove through the edge (if that's possible).
Sort of taking inspiration from one of Dave's old videos where he did the same for his panel of µCurrents for testing.

*normally i make my own but double sided boards are not my forte, especially not at this scale.

Ps: I can inlude more files of my boards, i just haven't yet because i don't want to litter the server with potentially unwanted files.

Hi,sir. The castellated holes will be made with a special process and the extra cost will be charged. You can check the fee when you place an order, like this:

[Mechatrommer]

yes we know, special process like my sliding table and cloned dremel, except i dont do debur with very fine sand paper as next step? or is it really special such as using tin plated tooth mouse?

[doppelgrau]

Aisler offers castellated holes with no extra costs: https://aisler.net/help/design-rules-and-specifications/castellated-holes

[jmelson]

Mouse bites aren't plated.

But, on a board with plated-through holes, why would having plating, or no plating, on the mouse bites be a big deal?  Same process each case.
Now, if this whole castellated thing is about using these to make connections after the boards are singulated, that is the problem for the board designer, not the fabricator.

Jon

[T3sl4co1l]

Again, if you just rip through plated holes, you're going to get tear-out and burrs.  Router bits go through meters and meters of fiberglass, they don't stay sharp forever and they need to run them as hard as possible to deliver those insane prices.

The big deal isn't doing it, it's doing it right.

Example: I ordered this recently,



Okay, so the photo isn't really angled to show off the castellated holes, my bad.  Suffice it to say, they look fine and have normal solder fillets.  They connect to pads of an odd pitch, for an expensive connector I don't have cables for; so I removed the connector and put on my own, and now I can use these [LCD panels].

The board was ordered as 0.8mm thick, normal proto, and got the usual flag, which I waived.  As received, they have prominent burrs.  I didn't happen to notice much tear-out on them, but I got more than enough extras to cover in case they did.  With just 20 holes to do, I went over the burrs with a utility blade, and soldered them down (a drop of superglue secures the side under the header).

Tim

[Refrigerator]

Aisler offers castellated holes with no extra costs: https://aisler.net/help/design-rules-and-specifications/castellated-holes

Will check them out, thanks. 

Router bits go through meters and meters of fiberglass, they don't stay sharp forever and they need to run them as hard as possible to deliver those insane prices.

Perhaps they use diamond cutters for castellations ?

[Refrigerator]

Well i got my design approved by PCBWay and ordered it.
It remains to be seen how hard i'll screw the boards up when i cut them with my old dremel.   

[thm_w]

yes we know, special process like my sliding table and cloned dremel, except i dont do debur with very fine sand paper as next step? or is it really special such as using tin plated tooth mouse?

Your dremel isn't CNC controlled, and I suspect you have no attached vacuum head to suck up the nasty glass dust.

Perhaps they use diamond cutters for castellations ?

I have seen these used, which they call "diamond cut":
http://www.frezycnc.eu/pcb-online-catalog/drilling-milling-and-routing/contour-router-bits-for-pcb/diamond-cut-endmills-for-pcb/

Probably more expensive up front and to sharpen as well.

[Mechatrommer]

Your dremel isn't CNC controlled, and I suspect you have no attached vacuum head to suck up the nasty glass dust.

thinking about it, maybe you are right and i was not really know what i was talking about, so i pull out my cutting setup with some unused prototype pcb to do diy castellation test for some minutes (i've never done this since no requirement so far, so this can be my learning process), the pictures worth 1000 words (different person will translate to different words). from before cutting, before burr and then deburr with small diy file,brush to clean off dusts and tweezer to peel off residuals. imho, its doable, up until how many boards you are willing to do this. if you concern about safety hazard, then i guess $4 per board service from fab house is worth it. i just use a 5V USB fan to blow off fiber glass dust, or just let the natural air bring them to surrounding ground. although i have and can mod my vaccum cleaner to do the task if i'm really concern. use mask if you require it, there are quality pricey one, and we have $1 covid mask one sold everywhere today, ymmv.