Home-made PCBs and vias - Page 1
Forum section: electronics / general

author: josuah
author_rank: Regular Contributor
timestamp: June 25, 2022, 11:40:05 am
content: Hello tinkerers...Do you have any suggestion for a better approach to vias than what I do (see below)?I currently drill a hole, put a wire through, and solder the wire on the top and bottom layer, following the track.It works reasonably well, but will not allow me to work with tracks under 0.5mm (currently doing 1mm).Any suggestion?I have just read abouthttp://fab.cba.mit.edu/classes/863.16/doc/tutorials/PCB_Rivets/onhttps://www.eevblog.com/forum/manufacture/cheap-source-for-0-6mm-via-rivets/Maybe that is a more proper solution.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 25, 2022, 11:53:25 am
content: I use wire, but I don't lap it as you show. I use 24 awg wire, which is about 0.020" diameter, and a small carbide drill (#72 = 0.025, #75 = 0.021). Anything in that range will work. The wire stays in by friction. If that's not sufficient, then flatten one end a little, and it will stay. Solder to the "annular ring" that surrounds pads and vias.Since 0.5 mm = 0.020", that method is not suitable for anything smaller. Drilling much smaller holes and smaller wire is a possibility, but such holes can be hard to drill without a good set-up.

author: sleemanj
author_rank: Super Contributor
timestamp: June 25, 2022, 12:12:37 pm
content: The easiest way for DIY vias... is not to have vias! Embrace 0 Ohm surface mount resistors for short hops across a trace or two and 0 Ohm through hole resistors for longer hops, soldered top-side.When it comes to actual vias, I have used rivets (0.8mm, aka eyelets), soldered both sides. But... it's not cheap and honestly doesn't add much other than being a bit easier to insert (but even then, not that easy) and looking a bit cleaner on top maybe.Wire sized for the via drill hole and solder is about as good as any.Of course, it's 2022, you can get factory made boards for cheap and fast from China, with as many vias as you want :-)

author: Whales
author_rank: Super Contributor
timestamp: June 25, 2022, 12:47:15 pm
content: Something I've thought of but I'm yet to try: fill the holes with conductive paint. You'd probably have to paint both sides separately to ensure a good connection. Likely still much faster overall?

author: mag_therm
author_rank: Frequent Contributor
timestamp: June 25, 2022, 01:04:42 pm
content: Up to 30 MHz, mix of analog and digital, I can use single sided boards just by adding a few wire links.This reduces the drilling.I have some self imposed rules and methods:Alway use board size 3000 by 2000 (inch).-This allows use of one vacuuum jig for uv exposure.-can get 4 boards from a 6 * 4 and 4 transparencies from one sheetUV exposure is short, 75 second under intense uv lamp - which helps sharpnessUse only 1206 resistors - to allow a track to get through if necessary as sleeman mentioned.Don't use TSSOP-14 - too difficult to solder (see lower left of photo)For logic I now prefer the SN74AUP single gates per package in SOT23 5 or 6 pin(See lower right of photo)https://app.box.com/s/us5pjv7tmcmzwp5ldb81uv6bnzgszgcb(Excuse the blur,can't get a tripod over that, as it is powered up)

author: josuah
author_rank: Regular Contributor
timestamp: June 26, 2022, 12:38:58 am
content: Quote from: jpanhalt on June 25, 2022, 11:53:25 amSmall drills and larger wire! That is what I need, I only have 0.030" drills.Way to go for when I need a via!Quote from: jpanhalt on June 25, 2022, 11:53:25 amSome trouble that I observed from drilling is the tip of the drill bit vibrating and oscillating. I will consider shortening the other side of the drill bit to reduce vibrations and see how it goes.Quote from: sleemanj on June 25, 2022, 12:12:37 pmI would never thought about using an SMD component for the purpose of hopping around a track... That is great!Quote from: sleemanj on June 25, 2022, 12:12:37 pmLet's see how far I can go with all these advisesQuote from: sleemanj on June 25, 2022, 12:12:37 pmIn my experience, it is more like cheaporfast, and the last FEDEX shipped one were marked as delivered while nothing ever came to my door at all.I might have simply been unlucky.Quote from: Whales on June 25, 2022, 12:47:15 pmI did not know about conductive paint! I definitely need some around.Quote from: mag_therm on June 25, 2022, 01:04:42 pmI see how the wires (red and bare), larger (like THT resistors) components can help me jump across a track...As always, I may place the important and sensitive signals first, then use these hacks for connecting +3v3/+5v/GND/I2C_SDA/I2C_SCL...Quote from: mag_therm on June 25, 2022, 01:04:42 pmUsing the poor man's approach of a acetone + toner transfer for now rather than photoresist. Not with best results I must say.I keep the advises for when I finally switch over to UV marking.Quote from: mag_therm on June 25, 2022, 01:04:42 pmCheck! I am right on. (I assume 30.00 and 20.00)Quote from: mag_therm on June 25, 2022, 01:04:42 pmWhy did I even bother with 0603 for something below 30MHz to begin with...Quote from: mag_therm on June 25, 2022, 01:04:42 pmIt looks like a key to making this happen is working with components that are comfortable enough to work (and rework) with.Quote from: mag_therm on June 25, 2022, 01:04:42 pmIt is very fine, thank you a lot for sharing that picture.

author: josuah
author_rank: Regular Contributor
timestamp: June 26, 2022, 04:43:01 pm
content: Follow-up:Cutting the base of the drill bit did help a lot with eliminating vibrations, I would recommend if you have spare drill bits.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 26, 2022, 06:13:37 pm
content: First, when I mention carbide PCB drills, they all have 1/8" shanks. The actual length of drill for, say, a #72 is quite short. There is no "vibration" of the tip. What you see as vibration is probably runout caused by your drill press and/or chuck.Trying to use a handheld drill with such small carbide wills would be challenging.Spare bits? Years ago, when ebay still had bargains, I bought at least 1000 solid carbide, resharpened bits from the Silicon Valley industry for about $0.012 per bit ($12 + free shipping). I have enough to use them as toothpicks for hors d'oeuvres at parties. They are a bit hard on teeth.Seriously, with a decent drill press (mine is a 14" JET made in Japan) and good chuck, the only time I break a #72 is when I move the PCB before fully retracting the quill. That is pretty infrequent.

author: josuah
author_rank: Regular Contributor
timestamp: June 26, 2022, 08:14:21 pm
content: Quote from: jpanhalt on June 26, 2022, 06:13:37 pmI only need good drill then, they might be properly designed for it. Thank you for the references.Quote from: jpanhalt on June 26, 2022, 06:13:37 pmNow that's a good reuse for these sharp things! Everyone gets a free dental scaling.Quote from: jpanhalt on June 26, 2022, 06:13:37 pmMaybe I was just having misalignment of the head on my dremel clone then.

author: shapirus
author_rank: Super Contributor
timestamp: February 23, 2024, 12:18:05 pm
content: Not really worth it to open yet another DIY vias thread, so I'll go eco-friendly and reuse an old one.Now, whereas actual vias are pretty straightforward -- just drill some holes, insert a wire with a closely matched diameter and solder it on both sides -- making holes for through hole components that sit flush against the board *and* must connect to traces on the component side, i.e., making the trace contact points hidden, is not so easy.One way is to drill a slightly bigger hole to accomodate the component's pin and a piece of wire, then solder the wire on both sides, then insert the component and solder it too. I haven't tried this, and, while it sounds feasible, it also sounds very tedious and error prone.Another way is to use rivets. There are brass rivets like this that come in different sizes:They'reavailable on Aliexpress.I ordered some to try. The smallest size is 0.9 mm (the tube part) claimed, more like 0.95 mm actual, getting wider towards the flange, so probably will need 1 mm holes, but may as well be 0.9 mm, depending on how it will comply under pressure.Inner diameter for the smallest ones is just above 0.5 mm.Easy to solder, they're tinning very well (and solder is very easily sucked into the tube, which is both good and bad).My plan, given that I don't have a tool to properly install them (to tighten and flatten on both sides), is to insert them from one side, press with something with a flat end (e.g. a drill bit) to flatten as far as it can go, then solder on that side. The other side can be soldered after the through hole component is inserted and cut just like a regular lead.However, the flange diameter is relatively large: flange OD in the 0.9 mm rivets is 1.9 mm. While this is fine for vias (unless the board layout is very dense), it will not work, especially with the bigger rivets, for through hole components, unless they have widely spaced pins: for example, the 1.3 mm rivets have inner diameter just large enough for the 2.54 mm pitch pin headers, but at the same time their flange diameter is sufficient to short neighboring pins.There is a workaround: the flange can be simply cut (using some good wire cutters) along the sides facing the adjacent pins, which will provide the required clearance. But this is also a somewhat tedious work, though it can be acceptable if the number of THT components that require such "plated holes" is low.Has anyone found any better rivets or small tubes that would have really small flanges -- just large enough to prevent them from sliding into the holes? Aliexpress is notorious for poor search results relevance, so I may have simply missed something suitable.

author: Whales
author_rank: Super Contributor
timestamp: February 24, 2024, 12:50:42 am
content: QuoteSidenote: sorting your search results (eg from cheapest to most expensive) forces Aliexpress to only show things that actually match your search terms.Often you will notice that nothing relevant shows up for certain search terms, instead it's lots of items you have looked at recently. If you then sort you will notice that it changes to say that nothing is available or only lists a few relevant itemsYears ago Alix search was so much better, it even let you specify the number of units you wanted to buy (!!!). It has seriously enshittified since then.

author: tooki
author_rank: Super Contributor
timestamp: February 24, 2024, 02:05:00 pm
content: Quote from: Whales on February 24, 2024, 12:50:42 amI literally just discovered that workaround (sorting by anything other than "best match" or whatever the default is called) the other day!Indeed, it seems their search has gone downhill lately. I truly do not understand this mentality of "show the user SOMETHING, ANYTHING at all cost" mentality, which affects both sellers (especially Chinese vendors, who stuff listings with irrelevant, imprecise keywords) and the platforms and search engines themselves, which seem to have decided that saying "sorry, nothing found" is an inexcusable sin. Neither of them seem to understand the value in being able to perform accurate searches.

author: wraper
author_rank: Unknown
timestamp: February 24, 2024, 02:26:01 pm
content: Quote from: Whales on February 24, 2024, 12:50:42 amSorting somehow removes like 70%-100% of relevant results as well. I usually search in incognito mode, this way aliexpress pushes way less irrelevant garbage into search results.

author: PlainName
author_rank: Super Contributor
timestamp: February 24, 2024, 02:47:51 pm
content: QuoteWhy is soldering the component pin on both sides not a decent workaround? After all, if the pin isn't in there the circuit isn't going to work anyway due to missing components, and if it is then the pin is as good as a wire. The only downside I notice (this is what I used to do) is where the component body might get in the way. For instance, screw connectors. But for those and similar I was always told to only route on the solder side anyway, so not actually an issue.

author: DavidAlfa
author_rank: Super Contributor
timestamp: February 24, 2024, 03:01:39 pm
content: Something like this, only a small bend so it doesn't fall off when soldering. Not that huge extension you showed.Found this in a NASA site (link):

author: shapirus
author_rank: Super Contributor
timestamp: February 24, 2024, 04:30:07 pm
content: Quote from: PlainName on February 24, 2024, 02:47:51 pmIt is, when you can. But there are cases when you can't: various terminals, relays, ZIF sockets (I'm doing this particular one now -- the testing polygon for the rivets), through hole electrolytic caps etc.Quote from: PlainName on February 24, 2024, 02:47:51 pmIt's not always possible to do it. Sometimes, when most of components are SMD, there is nothing except ground plane on the bottom side, and it's desired to route everything, including the THT connections, on the top side.This is the ZIF socket for 2 x SOT-23-6 that I'm now making a breakout board for (to use with a solderless breadboard). Yes I didn't find a ready made one -- there are some with super big footprint and weird pinout (the respective pins of the two ICs are shorted), so I had to buy one of them and actually desolder the socket and create my own board.There are 12 pins, which need to be routed to two sets (2 x 6 pin) of pin headers along the longer edges of the socket. I could not find a way to route all of them on one side (except for using jumper links which I didn't want to), so had to use both sides. The upper side's traces need to connect to the socket's pins where there is not possible to solder them directly (right under the body of the socket), so a DIY plated through hole has to be used.Workarounds are fine where they are applicable, but sometimes you really need to use something that can serve as a PTH substitute.

author: DavidAlfa
author_rank: Super Contributor
timestamp: February 24, 2024, 05:03:30 pm
content: Then it's pads, not vias

author: KrudyZ
author_rank: Frequent Contributor
timestamp: February 24, 2024, 05:16:58 pm
content: 0603 resistors are just the right size to bridge a standard 1.6 mm PCB THROUGH the board.The need a through hole of around 0.9 mm diameter.Use a 0 Ohm resistor to make vias or if the line actually needs a resistor then just put that through the hole.For ease of assembly, these should be put in first by placing the bare PCB on a flat surface.Insert the resistors where needed and solder from the top. Flip the board and solder from the other side.Since the resistors are mechanically constrained, soldering is really easy and they also won't fall out when soldering the second side.If you need finer pitch, i.e. smaller holes, then start with a thinner board, i.e. 1mm for 0402.

author: shapirus
author_rank: Super Contributor
timestamp: February 24, 2024, 05:22:51 pm
content: Quote from: KrudyZ on February 24, 2024, 05:16:58 pmLol that's a nice one. I wonder if it's more or less elegant solution than a tight fitting copper wire...I guess I'll order some zero ohm 0603 resistors just to have them in the kit.Doesn't solve the PTH issue though.

author: shapirus
author_rank: Super Contributor
timestamp: February 24, 2024, 06:19:47 pm
content: The smallest rivets mentioned above used as PTH:Quite usable approach, the downside of course being that the flange has to be clipped.Used a 1 mm drill bit (Chinese millimeters -- more like ~0.97 in reality), and it makes perfect holes for these 0.9 mm rivets: they slide in with a little bit of force, just the right amount. I put solder paste in and around the holes before putting them in, then flattened them and then heated the board with hot air to let the solder paste make joints where it would want to. Of course I ran a piece of wire through each of them before heating to clean the solder paste from inside.

author: shapirus
author_rank: Super Contributor
timestamp: February 26, 2024, 10:24:14 pm
content: So I have tested these rivets in the role of vias... Nah. They work, yes, but the result looks ugly and it's just too much hassle to set them and solder in properly.For PTH, yes, it's a good solution (except that the flanges have to be cut to make clearance where it's needed), quite usable. For vias, no, plain piece of wire soldered on both sides is better in every aspect.

author: MathWizard
author_rank: Super Contributor
timestamp: March 06, 2024, 04:05:42 pm
content: Some old DMM's I've worked on made via's by rolling little strips of some copper alloy, into cylinder's with just a little overlap. IIRC, nothing extended out of the hole by any amount.IDK if they were glued in at some point, but some of them came out when working on it with the soldering iron. Most of these had through hole parts in them tho, and they used them even if the trace was only on 1 side. They certainly worth my time to put back.

author: Howardlong
author_rank: Super Contributor
timestamp: March 06, 2024, 04:28:03 pm
content: A related question...How do you drill small holes (say, sub-0.6mm) without breaking the bits? Presumably there's some kind of precision pillar drill available that I've yet to come across.

author: PlainName
author_rank: Super Contributor
timestamp: March 06, 2024, 04:42:54 pm
content: Use something with zero lateral play. CNC machine works okAlso, very high speed (the tiny diameter means that the surface speed is really low unless you spin it at 20krpm and up) and don't push it in too hard - it is cutting slowly and doesn't have much strength against bowing.

author: reboots
author_rank: Regular Contributor
timestamp: March 06, 2024, 04:52:43 pm
content: Back when I was willing to make my own double-sided boards, I used brass "head pins" for jewelry making to populate vias. The pins have a very small flat head.I tried a few different sources. Some pins vary too much in size and shape to use as the basis for a reliable design. Some have coatings which don't wet well with solder, since they are sold for appearance and not for electronics use. I recommend sourcing suitable pins, then measuring them carefully for via drill and annular ring dimensions to incorporate into your design.Quote from: Howardlong on March 06, 2024, 04:28:03 pmDoing this by hand requires an industrial precision drill press (sometimes called a "sensitive" drill press), or a purpose-built PCB drilling machine. Hobby drill presses have too much flex and vibration for carbide PCB drills. High-speed steel drills are easier to use, but dull quickly in fiberglass laminate.I built my own inexpensive PCB drill press, as detailed below. The design had a few issues, but it was very successful with drills down to 0.25mm.http://reboots.g-cipher.net/pcbdrill/index.htmlHere is someone who mounted an air die grinder on a small industrial linear slide, for a compact, economical and successful solution.https://www.instructables.com/%2430-High-Speed-PCB-Drill-Press/

author: shapirus
author_rank: Super Contributor
timestamp: March 06, 2024, 05:54:04 pm
content: Quote from: MathWizard on March 06, 2024, 04:05:42 pmNow that's an idea. I have some copper tape with a glue layer. It can be used not only for creating copper traces, but also for vias. That's going to be very labor intensive though.

author: shapirus
author_rank: Super Contributor
timestamp: March 06, 2024, 05:58:03 pm
content: Quote from: Howardlong on March 06, 2024, 04:28:03 pmNear zero chance of doing it with a hand-held drill.I bought this mini drill press specifically for the task:https://www.aliexpress.com/item/1005004599678055.htmlWorks very, very well. Zero runout (I guess that's the term for the bit going slightly off the axis so that its end draws a circle instead of a point), zero axial and radial play, and that's pretty much all that matters.It's built down to a price, but they made the really important parts really nice. There seems to be a small percent of people having worse experience than mine, so YMMV.

author: Howardlong
author_rank: Super Contributor
timestamp: March 06, 2024, 06:18:27 pm
content: Quote from: shapirus on March 06, 2024, 05:58:03 pmInteresting. How small can you go with it?

author: shapirus
author_rank: Super Contributor
timestamp: March 06, 2024, 06:42:47 pm
content: Quote from: Howardlong on March 06, 2024, 06:18:27 pmI think the smallest I have tried so far was 0.6 mm, as that's the diameter of the wire I use to make vias and I can't remember having to drill holes for anything smaller than that. Could easily go smaller if I needed, as it's really very well aligned. One of key factors is to press the PCB down firmly to the base and not let it get lifted, or moved otherwise, as the drill bit starts to go into it. The PCB moves, the drill bit breaks. Extra attention required when you drill smaller holes first to be later used as guides for larger bits: those larger bits effectively act as screws, trying to lift the board up.I'm assuming hard alloy bits (typically tungsten carbide based), of course. They are super brittle. Steel bits are more tolerant to misalignment, but even when made of HSS, which is a wear resistant type of steel alloys, they get dulled very quickly by the glass textolite material, because, guess what, glass is hard.BTW I have also successfully drilled half-holes with it, where the center of the hole lies right on the edge of the board. Hold the board firmly, lower the drill very very slowly, and it works just fine. The diameter was 1.0 mm in that case. This means that the lateral stiffness of this drill press is also quite decent. Might probably be used for some very simple light duty milling jobs as well, even though the RPM (about 3k/min IIRC) is nowhere near what is good for milling, but I really don't want to abuse it this way not to cause excessive wear of the axles and bearings.

author: tooki
author_rank: Super Contributor
timestamp: March 06, 2024, 09:31:23 pm
content: Quote from: Howardlong on March 06, 2024, 04:28:03 pmIn terms of hobbyist tools, a Proxxon "dremel" tool (I use theIBS/Emyself because it has extremely low runout of 0.03mm maximum, despite costing under 100 euros) together with a Proxxon drill stand (I use theMB 200). Unlike Dremel's wobbly-ass drill stand that uses a plastic thing to hold the machine, the Proxxon drill stands are all-metal and are rigid enough to drill tiny holes.I think 0.5mm is the smallest I've tried on it so far, but thinner should be possible.At my old job, they had a dedicated PCB drill press, and using that, I drilled 0.3mm holes into aluminum sheet. Lemme tell you, though, you justlookat a 0.3mm carbide drill bit the wrong way and it snaps! Working with them requires extreme care and focus; don't do it on a day when your hands are shaky or you've had too much coffee, nor when there are people milling around!

author: sleemanj
author_rank: Super Contributor
timestamp: March 06, 2024, 10:33:59 pm
content: You can use a hand-held (eg dremel type) rotary tool to drill down to 0.3mm, as long as you use HSS bits, don't bother trying to use carbide ones at that size as you will of course break them too easily.Of course maybe the hole will end up a fraction bigger than 0.3mm, but does it really matter. 0.3mm is the thinnest HSS bit I think you can get.Micro size HSS will wear out quickly, they are disposable consumables, if you use 1 or two per PCB, it's not the end of the world.Keep the bit length short.

author: shapirus
author_rank: Super Contributor
timestamp: March 06, 2024, 10:56:02 pm
content: Quote from: sleemanj on March 06, 2024, 10:33:59 pmThis is a good point btw. Considering the amount of hassle they save, they may be better than carbide bits even if you use a few per PCB. And maybe even cheaper: they are actually dirt cheap.

author: shapirus
author_rank: Super Contributor
timestamp: March 10, 2024, 11:17:28 pm
content: Quote from: shapirus on March 06, 2024, 06:42:47 pmJust to test it, I tried to drill a 0.3 mm hole, which is the smallest bit size I have. No issues whatsoever, worked like a charm. And it was a carbide bit.