Drill hole sizes in Milled Board PCBs? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 24, 2023, 05:23:03 pm
content: Hi,We wish to make a few prototypes of our 20W Flyback SMPS.We dont want to wait the 5 days for delivery of JLCPCB etc.So we will do it on Milled Board.Its a single sided board which we cut to size....we then mill out the unwanted copper to leave the tracks...we can have NPTH's, so that we can do thru hole parts too...Anyway, has anyone ever done this?....is it best to use just one drill size?Obviously a good number of the tracks will just have to be wired, since its not double sided.

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2023, 05:46:13 pm
content: The fact that you’re asking this question means you guys haven’t done it before, which means you have no idea how much experimentation and faffing you have ahead of you to even get one working board, never mind several.There are plenty of local PCB houses that will do next-day service for you. It comes at a price of course, but compared to dicking around with PCB milling (something that looks like a great idea, but which everyone soon abandons after discovering how fickle it is), it’s worth it.If you absolutely must DIY it, use a laser printer and do toner transfer and then etch yourself. Just use the backing paper from large laser labels. But it’s not free from trial and error, either.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 24, 2023, 06:10:34 pm
content: You do now that there are PCB houses other than JLCPCB..?Even some in the UK, who can turn boards round in 24 hours if you really need it. Not cheap (about £200) but likely cheaper than your time dicking around with single-layer hand-made PCBs.If you really want to DIY, double-sided photoetch or toner transfer is readily doable on the sort of resolution you're going to use on a PCB.

author: Faringdon
author_rank: Super Contributor
timestamp: July 24, 2023, 07:07:29 pm
content: Thanks, but how do you get the drill holes when you just use chemical etching?

author: MK14
author_rank: Super Contributor
timestamp: July 24, 2023, 08:05:33 pm
content: Quote from: Faringdon on July 24, 2023, 07:07:29 pmhttps://www.electricstuff.co.uk/pcbs.htmlQuote

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2023, 08:34:59 pm
content: Quote from: Faringdon on July 24, 2023, 07:07:29 pmYou use a drill.

author: Faringdon
author_rank: Super Contributor
timestamp: July 24, 2023, 08:40:05 pm
content: Thanks MikesElectricStuff.The people i work for tell me that the photographic method is not as good as using a milling machine to mill away the copper from a copper clad board.QuoteThanks, but i would need say a 0.6mm drill, and a 1mm drill, or 1.2mm.......or maybe i could do them all as 0.6mm and then kind of "pillage" the drill hole with the 0.6mm drill bit when i need the hole to be , say 1.2mm?My biggest "leg" is 1mm diameter.....so ill need 1.2mm for that.Is it a Dremel drill that you refer to, with a stand?Is this OK?

author: Gyro
author_rank: Super Contributor
timestamp: July 24, 2023, 08:57:14 pm
content: Wow, 3 drill bits!Go on, live a little!Well, you could use a hand Archimedes drill if you want to give a PCB fab turnaround a fighting chance. I keep one for the odd hole. Alternatively (probably cheaper than a Dremel and stand)...https://www.ebay.co.uk/itm/291698846631

author: jpanhalt
author_rank: Super Contributor
timestamp: July 24, 2023, 09:17:37 pm
content: Unless you have your 51st "boss" lined up (assuming you are on #50), I humbly suggest that you order the boards from JLCPCB as a backup, should this endeavor take more than 5 days to get the details worked out.

author: abeyer
author_rank: Frequent Contributor
timestamp: July 24, 2023, 09:30:40 pm
content: Quote from: Faringdon on July 24, 2023, 08:40:05 pmYou would think they'd have all these details worked out then.QuoteAny lateral forces on a carbide drill that small will shatter it. If you need multiple size holes you need the appropriate drills. The cheap Chinese ones are often sold as a set of common sizes anyway.QuoteEither of those will "work", but often at the cost of breaking a lot of drills. A proper mill/cnc/drill press with a well-aligned spindle is your best bet.

author: David Aurora
author_rank: Frequent Contributor
timestamp: July 24, 2023, 10:31:32 pm
content: Quote from: Faringdon on July 24, 2023, 07:07:29 pmJesus fucking Christ.

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2023, 11:48:34 pm
content: Quote from: Faringdon on July 24, 2023, 08:40:05 pmThen you should do exactly the opposite of everything they tell you, because that’s as wrong as humanly possible. Commercial PCB production uses pretty much exclusively photographic processes, multiple ones per PCB (one or more for each copper layer, plus one for solder mask on each side, plus one for making the screens used to apply the silkscreening). Milling PCBs is such a slow, fiddly, poorly controlled process that even hobbyists rarely use it, and nobody uses it commercially.Photographic processes are also what are used to make every single semiconductor made. So… it’s not a bad process.Quote from: Faringdon on July 24, 2023, 08:40:05 pmOh, the humanity! Three whole drill bits!What kind of dipshit operation are you guys running? Seriously. My home electronics lab —which is literally a small area of my bedroom— is better equipped than what you guys are using to make prototypes for an ostensibly commercial product. Absolutely laughable, in the not humorous way.Quote from: Faringdon on July 24, 2023, 08:40:05 pmI use a drill press composed of the Proxxon IBS/E in the MB 200 stand. The Proxxon has really low run-out (rotational eccentricity), and the stand is rigid enough, to use the extremely brittle carbide drill bits that are necessary for FR4 if you expect the bits to last more than a few holes before going dull.You cannot handhold when using fine carbide drill bits. They snap if you look at them wrong. You must use them in a drill press or milling machine.Do not use a Dremel brand unit. They have inferior run-out, but above all the Dremel drill stand is made of plastic that flexes too much, making it incompatible with carbide drill bits.But surely the milling genius you work for could have told you all this, right? 🤣Quote from: Faringdon on July 24, 2023, 08:40:05 pmForget it. You can’t handhold, and even if that were in a stand, it’s going to have shitty run-out that’ll snap your carbide drill bits.EDIT: When I replied before, I looked at the poster frame and dismissed it already due to the crappy chuck. Now I see that it’s a fucking MANUAL reciprocating hand drill. You’re either trolling us, or you’re even fucking stupider than I thought possible. You’d have to be batshit crazy to think it’s worth your time to make holes with a manual drill compared to paying for overnight service from a PCB house.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 25, 2023, 08:08:50 am
content: Quote from: Faringdon on July 24, 2023, 08:40:05 pmNonsense. You need to spend many thousands on a milling setup to get the same quality as a couple of hundred spent on a laser printer, UV exposure box and some chemicals.In a "proper" workplace you may have some health & safety issues to address with the chemicals, but if this was a "proper" workplace they'd realise that paying about £200 for some next-day prototype PCBs is the most cost and time-effective way to do it.

author: Gyro
author_rank: Super Contributor
timestamp: July 25, 2023, 09:06:13 am
content: Quote from: tooki on July 24, 2023, 05:46:13 pmFyi, you can get toner transfer paper that's made of corn starch, it dissolves away without leaving a mess of paper fibres (glossy magazine method). Useful on occasion and, I think, a bit more reliable than label backing - better adhesion and dissolving is a bit less risky than peeling after ironing.

author: David Aurora
author_rank: Frequent Contributor
timestamp: July 25, 2023, 11:23:55 pm
content: Quote from: Gyro on July 25, 2023, 09:06:13 amThe thing is, if any of this situation was actually real and this DIY board was truly necessary, you would skip the experimenting with random paper thing and just buy proper Press-n-Peel to get it done.In reality though, there is no board and there is no deadline. There's just Faringdon being Faringdon and turning completely imaginary situations into moronic questions.

author: tooki
author_rank: Super Contributor
timestamp: July 26, 2023, 12:15:43 am
content: Quote from: mikeselectricstuff on July 25, 2023, 08:08:50 amHeck... a place I worked atdidspend thousands on a purpose-built PCB milling machine. It wound up in the e-waste skip after sitting around collecting dust for years because it was just too much hassle to get anything usable out of it, according to my boss.My toner transfer attempts worked out better than the PCB milling machine, apparently. Doing it by UV exposure would undoubtedly be better still. We had a UV exposure box and etching tank, too. But ultimately, we just ordered PCBs from JLCPCB and called it a day.

author: IconicPCB
author_rank: Super Contributor
timestamp: July 27, 2023, 02:02:20 am
content: Hello Faringdon,At the risk of getting attacked ... YES you can do it all using mechanical copper ablation ( milling).I used to do it for living, offering PCB fabrication service.I no longer do it simply because the Asian PCB shops are so much cheaper but then there is that old sayingSELL ON PRICE, LIVE ON RICE.I am sure You would not appreciate getting paid say a weekly wage for a months worth of work because that is what the JLCPCB crew is doing in an environment which is much more automated than anything You may find in Your industry.So if time is of importance, You need to do things in a particular fashion and the results will be excellent.A rigid machine , a true running spindle with low run out at a minimum of 20KRPM, micro grain carbide tools pointed for work with FR4 material and software to extract the tool path information.

author: David Aurora
author_rank: Frequent Contributor
timestamp: July 27, 2023, 04:21:26 am
content: Quote from: IconicPCB on July 27, 2023, 02:02:20 amYes, you CAN make a board on a CNC machine if you have to.But the claim was that they couldn't wait a few days. It's already been a couple days, based on my own experiences I think it's likely the things would have showed up before the weekend if they had ordered them from JLCPCB. If it was really urgent it could have also been toner transferred 2 days ago, assembled and already tested.There's now another thread I saw before asking for a hand holding tutorial about how to use a CNC machine to make a PCB, meaning no board has been made yet. Let's assume the CNC machine is already perfectly set up, runs great, and all required end mills/board blanks/etc are present.Given that Faringdon has already shown that they didn't even know how to make a hole in a board, what do you think the chances are that they're going to be able to mill a board faster than the real boards would have arrived without crashing the spindle/breaking endmills/aircutting boards/etc?A moot point though, of course, because none of this is real anyway.

author: tooki
author_rank: Super Contributor
timestamp: July 27, 2023, 09:12:00 am
content: Quote from: Gyro on July 25, 2023, 09:06:13 amI have always just used transfer paper sold specifically for the purpose (the yellow stuff from aliexpress). I suggested laser label backing because it’s something that can be procured from any office supply store.

author: SMTech
author_rank: Frequent Contributor
timestamp: July 27, 2023, 09:49:23 am
content: Quote from: tooki on July 27, 2023, 09:12:00 amThat is assuming the evil masterminds that trafficed him from oompah-loompah land let him out of the basement he is chained in.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 29, 2023, 02:16:25 pm
content: Running either a PCB prototype milling machine or high-quality, reliable etching line, requires quite some work (maintenance, know-how, instructing others how the process works), it would be best to have a dedicated worker running it (won't take full 40hrs/week though, so they could do something else too).Hand-drilling is fine when you have some dozens of holes per board. CNC drill becomes handy when you have more. A genuine Dremel, with good condition bearings (they wear out) can handle hole sizes down to about 0.5mm fine, maybe 0.4mm if you are lucky. Below that, the tiny carbide drill bits snap too easily.Tungsten carbide drill bits are not expensive, if you want to run that process you would buy at least 6-7 different sizes, 20-30pcs each so you don't instantly run out when they snap. It's annoying if you need to adjust your PCBs all the time to suit the limited drill bits.

author: c64
author_rank: Frequent Contributor
timestamp: August 10, 2023, 04:42:00 am
content: For single sided board I would use paper-based pcb, not FR4. Easy to drill with normal cheap drill bits

author: Berni
author_rank: Super Contributor
timestamp: August 10, 2023, 05:10:33 am
content: Anyone who thinks making PCBs at home is worth it is one of these:a) Does not know you can get high quality PCBs done in china for <1$ per PCB in 1 weekb) Has never tried to actually make a PCB at home (trust me it is horrible)Sure doing it at home is faster than 1 week. But you are going to need equipment, spend a lot of work, make a lot of mess. Only to make a PCB that is far inferior to a chinese PCB.Can you do 5 mills track/space on your DIY setup? Can you do metalised 0.2mm vias? Can do you a soldermask? How about 4 layer boards? (chinese do 4 layer for a few dollars per board). How many hours of work does it take you to produce a PCB?

author: c64
author_rank: Frequent Contributor
timestamp: August 13, 2023, 02:28:11 am
content: Quote from: Berni on August 10, 2023, 05:10:33 amWhy don't you tell us how? $1 delivered, right?Quote from: Berni on August 10, 2023, 05:10:33 amI can do single sided board in under 1 hour. This is what I usually prefer to breadboarding

author: c64
author_rank: Frequent Contributor
timestamp: August 13, 2023, 02:30:02 am
content: Quote from: Berni on August 10, 2023, 05:10:33 amIf you are doing single sided board, you probably don't need any of this

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 13, 2023, 03:03:47 am
content: I can't believe how bad that PCB drilling video was...I mean, look at the PCB..Then the handheld push drill!

author: Bud
author_rank: Super Contributor
timestamp: August 13, 2023, 03:38:57 am
content: I did 6 mil track/space PCBs at home. Not as horrible as someone is trying to portrait here.

author: Berni
author_rank: Super Contributor
timestamp: August 13, 2023, 12:24:24 pm
content: Quote from: c64 on August 13, 2023, 02:28:11 amAttachment shows a order at JLCPCB for 5 boards 100x100mm. Comes together to 3.44$ with shipping so that is $0.68 per board.Tho to be fair you actually want the faster shipping that brings you to about $18 total so $3.60 per board. But still that is dirt cheep. The BOM cost on most of my boards is way more than that. Then i will spend easily over an hour to assemble a reasonably sized board, so the figurative cost of my time is more than the PCB too (and the wages here in Slovenia are far from high)Quote from: c64 on August 13, 2023, 02:28:11 amBut with the typical complexities of most PCBs it takes FAR more time in the PCB layout phase to design them.For board simple enough to be quickly thrown together on 1 layer i would likely be even faster just building it by hand on some perf board. This is why i have lots different kinds of perfboard in 2.56mm and 1.27mm grid pitch and some SMD breakout patterns.If i am doing anything serious il just go for a 4 layer chinese PCB. They are cheap, save me time in routing it, and provide me with a nice solid ground plane for when i need high speed or low noise performance.

author: c64
author_rank: Frequent Contributor
timestamp: August 15, 2023, 04:30:53 am
content: Quote from: Berni on August 13, 2023, 12:24:24 pmYour attachment is 2-3 weeks - not one as you claimed before. If I want something right now, 2 weeks is sort of too long.For Australia jlc is 2-4 weeks.DHL to Australia is $20 with one week delivery, which IMO it too much for one simple board (yes I say one - even if they send me 5, I only need one)But of course I'm talking about something very simple. All other times I just order 4-layer boards, and don't even bother trying to fit it into 2L

author: fourfathom
author_rank: Super Contributor
timestamp: August 15, 2023, 05:28:29 am
content: Quote from: c64 on August 15, 2023, 04:30:53 amIt's not much different when shipping to the USA. But how much is your time worth? Sure, I waste time on all sorts of frivolous things, but when it comes to PC boards I would much rather spend $20 for a clean board and use my time for more interesting stuff. Plus the "extra" boards make great drink-coasters.

author: Berni
author_rank: Super Contributor
timestamp: August 15, 2023, 02:43:11 pm
content: I tend to tag my PCB orders onto existing orders at work, so i never really looked at the shipping because since i only pay for my boards.I like getting extra boards even if i need 1 or 2 at the moment. Sometimes i screw something up and need an extra board for another try rather that salvaging the existing one. Sometimes i need to assemble an extra unit. Not like i am paying 30$ per board and being forced to buy 5 of them.The point is that getting professional PCBs no longer costs >100$ like it did 15 years ago. They are cheap to the point that it doesn't really matter if it is 1$ or 5$ per board. It is so cheep that you don't really consider it as a significant price in a project.Heck it has gotten to a point where i have ordered purely mechanical PCBs with no copper on them, just because i can get a piece of FR4 cut exactly to my technical drawing for just as cheep. Hard to get any other material cut and drilled to order like that, and heck FR4 has some impressive mechanical properties too in terms of strength and resilience. Tho i likely would not be doing that if i had a CNC.

author: Microdoser
author_rank: Frequent Contributor
timestamp: August 15, 2023, 03:39:02 pm
content: Personally, I'd wait 5 days and have a professional looking board at the other end that has been tested. You can have a screen print on it and everything. Personally, I wait for the slow delivery because that gives me time to work more on software and housings, if it's a prototype.If I bought a device, and it had a home milled PCB populated with THT components (and it was any date after about 1978) I'd send it back straight away because either the product or the company aren't going to last long.If you just want to test the circuit, breadboard it. If you want to sell a product, order some PCBs and populate them with SMT components. I don't see the point, personally, for home milling a PCB in any sort of professional environment.PCBs are so cheap, I order them for endplates on housings, just because then I can get them predrilled with holes (either for fixing screws or RJ45 connectors or whatever) and a mask to label the holes. They are accurate to sub-1mm accuracy, so the fit is practically perfect, and they cost about £1 each, delivered. If your business relies on getting a turnaround quicker than a week, either you need to mess around on a breadboard some more, or you need to plan ahead more than a week...

author: PlainName
author_rank: Super Contributor
timestamp: August 15, 2023, 03:53:59 pm
content: Quote from: Berni on August 10, 2023, 05:10:33 amHello, you forgot c) Done it successfully; does it when appropriate.I get proper PCBs from JLCPCB but sometimes I want a quick and small prototype (perhaps a SMD to 0.1" adapter to wire onto a breadboard, or a bunch of parts that are too tedious to manually wire on stripboard). And when I want it I want it now, even if that's a Saturday afternoon. Ain't no local or worldwide PCB house that's going to manage that for any amount of money.As with a lot of thing in electronics, there are biased views that just get engrained in the mass psyche and become de facto red lines. Like gotos in software. Wannabes just parrot these 'rules'; knowledgeable users know when it's appropriate to 'break' them.Having said that, as others have pointed out, getting to the point where one can think "I know, I'll run off a board right now" and 15 mins later have it in their hands takes a lot of dicking around and bad outputs to learn from. If they are set up to do it then Faringdon wouldn't be asking about it and they would just do it, so they're not and they won't be for quite some time. JLCPCB is the way to go with this.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 19, 2023, 05:46:32 am
content: Home-made PCBs are not substitutes to commercially made PCBs, they are substitutes to other quick prototyping techniques e.g. soldered or solderless breadboards, dead-bugging etc. Deadbugging and breadboarding is really fine up to some tens to maybe a hundred of connections, but at some point the time in stripping insulation, cutting, tinning, soldering, gluing down (a minute per connection) becomes way more than the "setup time" of making a PCB (2 hours) while drawing traces in PCB EDA is pretty fast (a few seconds per connection) and easily verifiable so less time spent debugging what went wrong. Adapter boards that route signals between connectors would be a typical example. Or a high-number-of-IO microcontroller prototype.

author: PlainName
author_rank: Super Contributor
timestamp: August 19, 2023, 09:26:16 am
content: QuoteExactly so, yes.