Why are castellations so expensive and are they really what i think they are? - Page 1
Forum section: electronics / general

author: Refrigerator
author_rank: Super Contributor
timestamp: November 21, 2020, 04:49:57 pm
content: 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 40Same 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 badIt'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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 21, 2020, 05:14:35 pm
content: 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

author: Siwastaja
author_rank: Super Contributor
timestamp: November 21, 2020, 05:17:46 pm
content: $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.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 21, 2020, 05:37:54 pm
content: Quote from: T3sl4co1l on November 21, 2020, 05:14:35 pmI 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 DMMI'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?

author: Refrigerator
author_rank: Super Contributor
timestamp: November 21, 2020, 05:42:40 pm
content: Quote from: Siwastaja on November 21, 2020, 05:17:46 pmYes 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 cheaperEdit: wooo my 1000-th post

author: Feynman
author_rank: Regular Contributor
timestamp: November 21, 2020, 05:47:59 pm
content: 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.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 21, 2020, 05:51:39 pm
content: 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.

author: cgroen
author_rank: Unknown
timestamp: November 21, 2020, 06:14:04 pm
content: Quote from: Refrigerator on November 21, 2020, 05:42:40 pmWhat do you think the developers of the ESP32 paid for their first prototypesI bet its different than what they paid for the next 20.000 boards

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 21, 2020, 06:20:32 pm
content: Quote from: Refrigerator on November 21, 2020, 05:37:54 pmwith 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.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 21, 2020, 06:34:54 pm
content: 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.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 21, 2020, 06:58:03 pm
content: you've been given the advice to not use a hand knife, been there.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 21, 2020, 07:17:39 pm
content: Quote from: Mechatrommer on November 21, 2020, 06:58:03 pmYeah it looks like i might need to just pull out my old dremel. I had actually forgotten that i have oneBut 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.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 22, 2020, 07:06:21 am
content: Quote from: Refrigerator on November 21, 2020, 05:42:40 pmObviously, it's produced in tens or hunderds of thousands...

author: jmelson
author_rank: Super Contributor
timestamp: November 22, 2020, 04:47:36 pm
content: 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

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2020, 04:52:36 pm
content: Mouse bites aren't plated.Tim

author: phil from seattle
author_rank: Super Contributor
timestamp: November 22, 2020, 06:39:17 pm
content: 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.

author: JLCPCB Official
author_rank: Regular Contributor
timestamp: November 23, 2020, 07:54:30 am
content: Quote from: Refrigerator on November 21, 2020, 04:49:57 pmHi,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:

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 23, 2020, 09:17:09 am
content: 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?

author: doppelgrau
author_rank: Contributor
timestamp: November 23, 2020, 10:17:25 am
content: Aisler offers castellated holes with no extra costs:https://aisler.net/help/design-rules-and-specifications/castellated-holes

author: jmelson
author_rank: Super Contributor
timestamp: November 23, 2020, 04:29:48 pm
content: Quote from: T3sl4co1l on November 22, 2020, 04:52:36 pmBut, 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

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 23, 2020, 07:24:19 pm
content: 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'tdoing 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

author: Refrigerator
author_rank: Super Contributor
timestamp: November 23, 2020, 09:27:32 pm
content: Quote from: doppelgrau on November 23, 2020, 10:17:25 amWill check them out, thanks.Quote from: T3sl4co1l on November 23, 2020, 07:24:19 pmPerhaps they use diamond cutters for castellations ?

author: Refrigerator
author_rank: Super Contributor
timestamp: November 23, 2020, 09:56:51 pm
content: 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.

author: thm_w
author_rank: Super Contributor
timestamp: November 23, 2020, 11:25:14 pm
content: Quote from: Mechatrommer on November 23, 2020, 09:17:09 amYour dremel isn't CNC controlled, and I suspect you have no attached vacuum head to suck up the nasty glass dust.Quote from: Refrigerator on November 23, 2020, 09:27:32 pmI 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.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 24, 2020, 06:16:14 am
content: Quote from: thm_w on November 23, 2020, 11:25:14 pmthinking 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.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 24, 2020, 11:51:29 am
content: Quote from: Mechatrommer on November 24, 2020, 06:16:14 amIs that a regular black/composite cutting disc?I jumped on ebay and ordered some diamond cutting discs, i don't expect them to arrive anytime soon but when they do they'll be nice to have.I wonder would it be worth it to prefill the vias with solder to avoid tearout?

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 24, 2020, 12:15:26 pm
content: Quote from: Refrigerator on November 24, 2020, 11:51:29 amits brownish or reddish. this thing is really fragile on hand or if you accidentally hit it with your finger while its on the shaft holder. i keep breaking them (not while cutting). so i bought 1 pack original dremel disc 36 pieceslike thisas long as you handle them like ESD sensitive RF component, they should be alright at cutting many pcb until they run small in diameter. i tried steel disc with sawtooth, that was a big no no, the teeth can stucked on pcb throwing it away, that can be dangerous. i havent tried diamond (steel like) disc. the black (fiberglass reinforced) disc, i have the stock but never tried it i suspect it will run poorer, i think the brownish disc is superb enough at cutting material like pcb laminate. the key here is the sliding table, try cutting with hand will be a PITA, not to mention countless disc you are going to break. ymmv.Quote from: Refrigerator on November 24, 2020, 11:51:29 amcan be a good idea too but i havent tried, imho higher speed disc rotation and slowly cutting thin layers in few passes may do the trick. looking at the zoomed picture earlier, the holes plating already covered with solder from factory, so i guess its hard enough from tear out while being cut.

author: asmi
author_rank: Super Contributor
timestamp: November 24, 2020, 02:36:42 pm
content: OMG all that trouble to save $30... Your time must be really worthless to do something like that.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 24, 2020, 03:34:26 pm
content: huh? that only took minutes, including taking pictures, photoshopping and present them to you. you havent to the thread where people are swearing on diy pcb from scratch, dealing with smelly chemicals, drilling and stitching vias and all just to save $30-50 shipping cost of a 5pcs $2 factory made pcbs, this is just one straight cut and a little bit filing. and i have other uses for that cutter too (hint: try to send few like 3-6 designs of very small pcbs to fab house) furthermore if you are going to have like 10-100 orders in the year, thats not a $30 saving. thats between owning a yacht and not owning a yacht.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 24, 2020, 04:03:10 pm
content: I did some test castellated pads on an AllPCB order recently - they queried it with 3 options, one of which was basically "try routing it as normal and I don't care what happens" . Worked OK but there were bits of torn plating left

author: asmi
author_rank: Super Contributor
timestamp: November 24, 2020, 04:27:59 pm
content: Quote from: Mechatrommer on November 24, 2020, 03:34:26 pmThat yacht of yours is gotta be super-cheap one and look more like a canoe. Hint - if you mass-produce PCBs, additional cost for castellations (or just about anything else for that matter) is going to be close to zero. Nobody in their right mind just goes into the website and orders 1M batch of PCBs.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 24, 2020, 04:36:42 pm
content: Quote from: mikeselectricstuff on November 24, 2020, 04:03:10 pmIn the first picture the bottom row of pads looks alot cleaner, did you clean them up or are they as-is?Could the direction of milling also be a big contributor to tearout?

author: thm_w
author_rank: Super Contributor
timestamp: November 24, 2020, 10:02:23 pm
content: Quote from: Mechatrommer on November 24, 2020, 06:16:14 amPlease wear a mask and maybe use a vacuum with HEPA filter or similar, don't blow the dust with a fan. If you need a few dollars I can send it.Interesting setup though.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 24, 2020, 11:54:35 pm
content: Quote from: Refrigerator on November 24, 2020, 04:36:42 pmIf you look carefully the bottom row all have folded-back plating tear-outs, just a bit more consistent.

author: GerardG
author_rank: Regular Contributor
timestamp: November 25, 2020, 09:36:32 am
content: Castelation on the bigger holes can be the routing through plated holes. This can go well on a double sided board.When using a multilayer it is easy to crack the connection to the innerlayer.One of the options to make good and clean castellated holes will need to include another routing step between Chemical plating and panel plating.1. cut panel from CCL2. Drill plating holes.3. Chemical copper in all the holes ans slots.4. Make NPTH slot along the plated holes.5. Panel plating. slots without chem. copper will not be plated.etc etcWhen your production company is making castellated holes in bulk , it will cost you a percentage on the board price, that is why modules like ESP can be produced cheap.When you want this in a prototype production it means that the complete production panel must be taken out of the production, do the extra work, put it back into the production flow.The cheap board manufacturers need to ask some extra for it because of possible damage to the whole production panels (for example 610mmx510mm).I hope this will clarify some of your questions.

author: Psi
author_rank: Super Contributor
timestamp: November 25, 2020, 09:49:04 am
content: I've noticed this issue too.JLCPCB are quite expensive for castellation hole if you need it on all 4 sides.Last time I needed a board with 4 side castellation holes it was 50% cheaper from PCBWay vs JLCPCB.PCBway have a tickbox for castellation holes, but with PCBway there's no extra cost for each additional PCB side with them.I'd hate to see what JLCPCB charge for a circular PCB with unlimited number of sidesIf you plan to half-cut them yourself I would recommend using some sort of disk/belt sander/grinder.I think you will get smoother & cleaner results than trying to use a dermal or a cutting disk.But make sure you wear a mask to avoid the dust and safety goggles.

author: Refrigerator
author_rank: Super Contributor
timestamp: November 25, 2020, 06:12:14 pm
content: Quote from: Psi on November 25, 2020, 09:49:04 amYou could argue that there's only one (continuous) side

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 25, 2020, 07:40:50 pm
content: numerically speaking, it should converge to $40...

author: Psi
author_rank: Super Contributor
timestamp: November 26, 2020, 08:42:35 am
content: Quote from: Refrigerator on November 25, 2020, 06:12:14 pmThey could argue that the step resolution of their XY depanelisation router makes it have like 500 sides

author: Refrigerator
author_rank: Super Contributor
timestamp: November 30, 2020, 01:35:16 pm
content: Received my boards today and they look super nice.But what is that i see? A mistake?Yep.I forgot to break out the RST pin on my micro, but it's programmed through SWD so is RST really necessary?No big deal i can solder a wire to the pin when i'm programming the MCU if i end up needing the RST pin.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 30, 2020, 01:46:51 pm
content: Quote from: Refrigerator on November 30, 2020, 01:35:16 pmnice. is that from pcbway? how much they charge for that panelization? ie comparing how much cost for not panelized vs panelized pcb?

author: Refrigerator
author_rank: Super Contributor
timestamp: November 30, 2020, 01:57:46 pm
content: Quote from: Mechatrommer on November 30, 2020, 01:46:51 pmThat's actually not a panelized board per se. I just stuffed as many of my boards in the 10x10cm space as i could fit and then added routing to make them easier to cut out.A 6x91 mm board costs close to the same as a 100x100mm board, hence why i jammed so many of them in there to get the most for my moneyThe cost was the same as 100x100mm board.Also i found another oopsie in my design. I made the breakout pins on the side with 2.54mm spacing to solder in a connector but forgot to make the holes large enough for the pins.Rookie mistakes.

author: thm_w
author_rank: Super Contributor
timestamp: November 30, 2020, 09:15:02 pm
content: Quote from: Refrigerator on November 30, 2020, 01:35:16 pmIf its atsamd or stm32, never needed RST for the initial programming.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 04, 2020, 10:24:23 pm
content: Cut my boards with with my angle grinder, no jig just freehand.Before cutting i prefilled the holes with solder. I think the castellations came out pretty well.There were some burrs that caused a short but i sorted that out quickly.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 04, 2020, 10:26:58 pm
content: Soldered my thing together and it surprised me how stiff it was after i soldered it.

author: ElectronRob
author_rank: Contributor
timestamp: December 10, 2020, 12:15:47 pm
content: Did you consider just having little wire jumpers with epoxy?My issue with non plated castellations is that over time, even with slight movement the left over pads will lift etc. Often a little uninsulated wire joiner is quite fast to solder and fairly robust.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 10, 2020, 04:16:13 pm
content: Quote from: ElectronRob on December 10, 2020, 12:15:47 pmThey're a bit of a fiddle to solder this way but i think wires would be quite a fiddle as well and i wanted the assembly to be rigid and it really is surprisingly rigid.I've also thought about the vias pulling out so i added some dummy traces to anchor the pins into the board.By the way none of the pins are left unused on my boards.

author: ElectronRob
author_rank: Contributor
timestamp: December 10, 2020, 06:38:11 pm
content: Great, glad its worked out well for you

author: AlexanderB
author_rank: Newbie
timestamp: April 19, 2021, 12:13:06 pm
content: Sorry for kicking a slightly older topic, but this one turned up pretty high in the google results when I wanted to figure out what the deal was with JLC and the castellated holes.The answer is here:https://jlcpcb.com/quote/pcbOrderFaq/Castellated%20holesQuoteSo basically, if you pay the steep fee (it was almost $75 today, apparently), they'll give your board special treatment to make it nice.If you don't, they just send it, and you most likely end up with some remnants of the plated holes, like what Mike got from AllPCBQuote from: mikeselectricstuff on November 24, 2020, 04:03:10 pm

author: GerardG
author_rank: Regular Contributor
timestamp: April 19, 2021, 01:02:57 pm
content: Hello Alexander,That is exactly what is meant.No extra fee, mill through the holes and they are castellated (sort off)No guarantee on the adhesion of the copper.Use the "routing before plating" method, get the nice clean castellated holes.