Making Circuit Boards WITHOUT Solder

[@ardufreak6973]

You have a dual head on the Lumen. Simply use one head as "paste"/ink dispenser and the other head to place the part!

[@dfgaJK]

A head addon to extrude solder paste would also be so usefully for solder paste. It would to make it possible to avoid buying a stencil and stencilling on the paste by hand!

[@isaacgraphics1416]

Absolutely! It might even eliminate the step of ordering PCBs if you use perfboard and use solderpaste to effectively create your own traces. People do this manually but it would be a lot less tedious if it was done by machine. You could go from schematic to prototype really fast

[@DEADB33F]

Could a diode laser melt solder paste in a localised area so the PNP can solder basic components as it places them without affecting the paste on adjacent pads? ...maybe would need some kind of dye adding to the paste so it's not as reflective as the laser melts it. Might also be slow, but for prototyping that shouldn't matter much.

[@StormBurnX]

some carbon black in the solder paste would certainly be both conductive of electricity and adsorptive of the photons from the laser.

[@dougcox835]

This actually sounds like a good idea. I think you don't have to worry about the solder being shiny because it's dark before melting so that would regulate the heat anyway. Once it melts and gets shiny no more heat is needed anyway. You could just slather the paste everywhere (no paste mask) and after laser soldering everything wash it all away. I do see an issue though. There would likely be paste under the components that didn't get washed away so that would likely short everything.

[@rallekralle11]

there are laser soldering machines, but they use wire

[@---..]

I like the idea, but I don't think it would work very well. If you just add enough heat to melt the solder, as soon as you start placing the part, it will wick away some of the heat and it will solidify. It might connect, but it won't make a good connection, which requires getting the pin, pad and solder all above the solder's melting point so the surface tension can flow it cleanly.

[@hifidom]

My suggestion: Add a solder paste dispenser and a laser to the pnp unit. The laser must be thermally monitored, otherwise the solder paste will explode due to overheating. Such a machine would solve so many problems on prototyping!

[@RoyvanLierop]

Some UV curable conductive glue might be an option, this would give you ample time to place the parts and correct mistakes. Add an UV laser and some custom pathing to cure them instantaneous.

[@MarkDurbin]

Doesn't the solder paste conduct before you put it in the oven?

[@dougcox835]

Yes, but it is not isolated in the Z axis so it just shorts everything. This is why you use a stencil and the pcb has the top layer called solder mask or simply mask layer. but paste would just jump right over all of that.

[@jgooding213]

@@dougcox835 neither are the conductive paints and inks used in this video?

[@aaronmdjones]

Not nearly as reliably. It's many small balls of solid powdered solder surrounded by a non-conductive flux.

[@MarkDurbin]

@@dougcox835 I assumed it would be applied in the normal way through the stencil.

[@jgooding213]

@@dougcox835 neither are the conductive paints and inks used in this video?

[@chrisdixon5241]

That was really impressive! I really like the idea of a solder / conductive paint head as part of the PCB placement process, and you're right, it would be a game changer for quickly prototyping. Good luck!

[@Magnetic999]

11:10 If you want to replace the solder stencil, you can use a solder paste jet printer.

[@mikeselectricstuff]

Have you seen the price of those - well into 6 figures

[@Sam-J_1]

I think you would highly benefit from using UV curing adhesives, that way you get the longevity of glue that doen't immediately start to dry as the PNP puts them down, and then when it's finished you can just cure it with an LED, or in the sun quite quickly.

[@JoelRehra]

Ohh and be carefull with heat emmiting parts... Carbon paint looses resistivity when heated up... Very useful to create e-fuses for firework ignition... but bad when it cooks your circuit because of the runaway effect ;)

[@excitedbox5705]

This is what a lot of printed circuit research is doing: You could try mixing up a really THICK mix of copper sulfate + water (might want to test some solvents) and put small drops on the pads, dip the components into a solution of citric acid (water+ vitamin C powder). This mixture makes copper nano particles BUT copper sulfate is also used for electroplating. My theory is that as the citric acid washes off the component and mixes into the liquid copper sulfate on the board, it will form copper particles AND electroplate copper at the same time, welding the nanoparticles into a solid connection. Nanoparticles of metal have a lower melting point at

[@christianbaumgartner7133]

Don‘t use Graphite! Use Lamp-Black (super fine Carbon Black)! I have experimented with both and Lamp-Black is much better. You need about 5-10 times more conductive material than the the Base too have a good conductivity. Best wishes from Germany, Christian B.

[@stephen_hawes]

awesome, thanks for the tip! Just bought a bunch for testing!

[@davidf2281]

@@stephen_hawes Please also remember, if you're getting into using super-fine powders, that they can be horribly carcinogenic. Properly rated masks etc required.

[@jonathancrossley6803]

Silver loaded epoxy is used extensively in hi reliability electronics e.g. Loctite 84-LMI Not sure how conductive it is before curing - usually cured at 150C for an hour or so. Also not going to be as cheap as something carbon based.

[@IggyJackson]

This is the level of excitement that got me into your videos years ago. My only input on this topic is that I know there are wood finishes that cure via UV. If you could find something like that, you wouldn't have to worry about it drying until you hit it with a big dose of UV

[@DragonFlaired]

Take a look at MG Chemicals 9410 - 1 Part Epoxy, Electrically Conductive Adhesive. We use this where I work for RF die bonding. Effectively a 24hr work time as it cures with heat so I'm not sure how well it conducts uncured but worth looking at

[@JoelRehra]

Super useful for fast prototype iteration. The best part of this is that you could reverse the process! Soak the board in solvent and use the machine to pick the parts off the board again... fully automating the testing of different components on a single proto-board. And having a paste extruder would allow to print on very precise custom resistor values onto a board just by varying the length and thicknes of the paste... Exiting to see where this will go :D

[@eshkrab]

Holy shit those LEDs lighting up on the lumen was the sickest thing ever

[@WaffleStaffel]

Probably a PVA adhesive is going to have the best properties, good viscosity, moderate drying time, strong once dried. Something like Mod Podge, or white glue that's been dried a little to thicken it up, mixed with powdered carbon, or silver/copper..

[@RestartVandelay]

The carbon paint looks very similar to something we use in electron microscopy to ground samples mounted in plastic. If you don't ground them then the electrons from the microscope accumulate in the sample making it progressively brighter until it is just a glowing white blob (there are ways around this but the carbon paint is the fastest/easiest). Microscopy supply companies like Ted Pella also sell a conductive carbon glue. I haven't used it but looking at the spec sheet it also uses acetone as a solvent so will probably flash off too fast for your use. Conductive 2 part epoxies might work for your situation with their extended working time but would be more annoying to apply and a lot harder to remove once fully cured.

[@insanegammer109]

Conductive epoxies are a thing, but they typically need to be cured with heat. Silver Filled epoxies are an industry norm.

[@dougcox835]

Just a suggestion, to make it last longer just thin it like paint thinner. You would need to know what solvent base this stuff is though. The smell would be a good clue. Whatever solvent has that same smell would be right. Just remember that thinning it also makes it literally thinner so you might need to apply more. You're right about the paint not being an adhesive but maybe you can put conformal coating on the board after assembly. That stuff definitely locks everything in.

[@bsc7812]

Dude. I love watching your videos. I play around with electronics as a novice hobby. But your project and your optimism just make me want to learn more. Keep up the good work bro.

[@ikocheratcr]

You could increase the viscosity by adding fused silica. The paint conductivity goes up as it dries because the conducting particles come together and start to form a path for current as solvent goes away. Long time ago I played with one that is basically nail polish with carbon and metal powder, for EMC shield painting.

[@ankhzet]

Just use low-melting-point solder and add the heat bed, could get away with as low as 47ºC, which would not burn the components and provide low-resistance, high quality contact. Mixing low-temp solder and flux would proubably make as close to a real-time plug-and-play solder paste as possible. Graphite lackers/inks have added resistance and also are mechanically unsound, they would just crumble under any prolonged stress, so application range is limited. Mixing graphite and glue would just add an insulator (glue) between graphite particles, so you would need to find a (at least semi?) conductive glue to make it work, or some king of post-processing to increase amount of continuous graphite chain-links, otherwise the resistance would kill any possibility of it being applicable at all, i think. Maybe, some kind of long-stranded graphene-glue emulsion? But all this is pure speculation on my part, so i'm waiting for the next video =). Btw. Pure experimentation for the fun of it, as in practice it would potentially add an additional degree of complexity to some circuits, as there are cases, when the order of components being connected matters (f.e., you would want to place current/voltage-limiting resistor or zener _before_ everything else). Maybe, add some routine/rule to placing sequence to always place such elements first?

[@ThantiK]

You can build the reflow into the PCB. I've seen people pump 12v into a ground plane ("plane" being somewhat loosely used; it was a tuned trace) in order to basically reflow the solder directly on-board. Then they break off the tabs that give access to the internal heating layers, and voila.

[@AdamDavisEE]

ACF is the film version - Anisotropic Conductive Film. Most of these films require pressure during placement, and heat to cure the adhesive. For the processes I've used it in, it requires 250psi (not a lot, given how small the component being pressed is) and 140C for 25 seconds (which is below solder oven temperature. ACP's downside is that the metal spheres, or metal coated plastic spheres, often don't stay equally distributed in solution, but you can place it with regular paste dispensers, and it can be cured with methods other than heat. You still need to use pressure on initial placement, though, to get the spheres embedded in both sides of the contact. The conductive solutions you've used should be fine for your purposes. Their high resistance compared to copper, and lower adhesion will pose problems for many uses. I expect that debugging a board with a hundred such connections is not going to be pleasant, and the relatively high pin to pin spacing this would be capable of might limit products that can be used. For instance a 0.5mm pin pitch 32 pin package might have trouble with either shorts with too much paste, or opens with too little. Unfortunately what that really means is that this is a replacement for simple pcbs that could probably be hand soldered and placed, and probably not a great fit for high speed prototyping. I'd like to see you succeed, and I certainly don't intend to dissuade you, if you can make this work for even those projects it would be a huge benefit for many.

[@epremeaux]

some ideas: - overall this process (or variations of it) would benefit greatly from a paste dispenser as the secondary tool on the P&P. - First step : (especially for components with more than two pads, modules, etc) load the paste dispenser with component glue. This is already a common job in a larger fab houses. Glue dot the center of the component, then pick and place it. Now it wont move no mater what ends up happening with the conductive pasting. - second step : after all parts glued down, reload the paste tool with conductive paste and dot right up against the corner of the leg-to-pad interface. OR.. somehow build a head with all three : glue, paste, and pick&place.. pick the part, then while over the footprint, paste all the pads, hit the glue dot and place the part. - The paste is messy without a stencil. If you want to dispense it by the P&P, you may need a knife or needle to "comb" between legs of SOIC, modules, etc to "cut" shorts. - some sort of UV/heat curable conductive epoxy would be awesome. Add a sharp UB laser to the head. The laser point should be thinner than the component leg of most SOICs, QFPs, etc. you could even gob the epoxy a bit, provided there is a cleanup step after.. selective laser conductive curing. Just run back and forth across the leg to the pad a few times.

[@jasonclark1149]

Neat idea! Next step is to install a paste/paint extruder onto the lumen, so that you don't need to manually pre-apply the adhesive. That would also eliminate the dry time issue if you can place adhesive then immediately place the part, and repeat. And you conveniently have two toolheads....

[@DavidKenny64]

Was looking to see if somebody already posted this suggestion. You win! But it would be even better if you placed a dot of actual adhesive under the main body of the part to take over the job fastening the part onto the board. Then the conductive stuff, put down on the next pass wont have the job of holding the part on. Now you place the part. Of course, parts with a thermal pads wouldn't need the adhesive.

[@BobHannent]

About 10 years ago I toyed with the idea of using either an inkjet printer or laser printer to print onto laminate film to create multilayer, flexible printed circuits. Conductive inkjet ink was pretty widely available but toner less so. For fast, short run production runs laminate is very interesting to me. But also imagine graphene or carbon nanotube toner ink being fused to PLA based laminate film? Perhaps I've just given away a billion dollar idea, but an idea is nothing if you can't execute on it.

[@RJ_Eckie]

Oh mannnn we all know where this is going and I'm excited!!

[@Luzgar]

How conductive is non melted solder paste ?

[@graealex]

Re: getting brighter - the solvent isn't conductive. When it evaporates, the distance between the actually conductive particles shrinks, reducing the resistance. It also shrinks in general. It's an obvious relationship - if you were to dilute the conductive paint even further, the resistance would increase and increase - so the reverse, the solvent evaporating will increase conductivity. I would also assume it's similar for solder paste, when heat liquefies and eventually evaporates the flux, or at least removes it from in-between the solder balls.

[@TheMadManPlace]

Why not use a 2nd head on the pick and place machine to apply solder to the pads just before placing the component? OR once the part has been picked and orientation determined, move the part over an applicator to place solder paste and then place the component. Either method will get rid of the need for a solder mask stencil and be more efficient as well. ANOTHER THOUGHT: Why not print (bubble-jet or whatever) the "green coating" onto the board with UV curing ink/paint/whatever? That would remove the need for that stencil as well. Even more savings when doing single or short run boards. FINALLY: I see that many use a laser printed image on a paper substrate to get the board ready for etching. So why not "simply" print the etching mask directly on the copper clad board? Your pick and place machine is a very effective solution for the problem of populating the board. Now it is time for you to revolutionize and simplify all the processes that come BEFORE "final assembly".

[@gxurma]

Hey Stephen, you have to press _and_ heat cure and cool down the z-tape, to get the part frozen in the correct position. I myself am experimenting with this. Not too reliable.

[@Malusifer]

Wonder if heating it up while in a vacuum seal bag would work.

[@graham8316]

Put the total ground on after the part. You coul could put sticky stuff under the resistor or LED in the middle to attach it and isolate each end and then drop the conductive paint on either side, maybe like epoxy. You could also make like a little epoxy sticker or something like it that outlines the pad. has two little wells, one for each pad, and separates them and it could attach onto the resistor part in the middle and then it would provide wells for the ink to sit in

[@biggusmunkusthegreat]

oooooh the lights going on as the pnp put them there was satisfying af. :D

[@BrainSlugs83]

For the z tape, you could place everything and then put it into an enclosure which applies the pressure. Like the old calculator displays that used a similar thing, except it was in vertical strips instead of balls, but the enclosure squeezing it down is what made the display connector sandwich work.

[@kevincolwell2115]

I work in hi-rel electronics... If there's a reason we can't use solder, a common choice for conductive adhesive is silver filled epoxy.

[@dennydravis8758]

An additional layer to this is that the conductive paints were reversible - so if a prototype placement doesn't work you can clean it up and try again. If you had an in-house PCB mill, that means you could really iterate faster and cheaper

[@zachhubbs8233]

Such a cool video, I love the visual of the LEDs coming online as the job ran! Maybe try mixing in some acrylic fluid retarder to slow the drying process.

[@SapioiT]

Would be nice if you also put in the description the exact names of the paints tested in the video.

[@Gentle_Chu]

Seems quite useful for prototyping. Using the second head on the lumen as an applicator you could pick up a part, put the pain down and then place the part. Do this for every component and you have a board for prototyping right off the machine. And having the paint be sturdy but still relatively easy to remove makes manual rework easy for development.

[@stephen_hawes]

yeah, this is what i was imagining too! would be easy to reduce excessive drying by dispensing paste for a single component, then placing just that part. a bit slower, but likely much more reliable.

[@Gentle_Chu]

@@stephen_hawes Once this is solved you only need a way of fabricating decent quality PCBs at home and you can get a consistent prototype turn-around time for simple project measured in hours! Tho homemade PCBs seems like a tough nut to crack.

[@Daisy_human]

Its so good to see you back on youtube

[@mikeselectricstuff]

higher supply voltage and higher resistor values will make it less dependent on the resistance of the ink

[@dermax9390]

If you just want the effect for like a video or smth you might wanna try how good gallium wets the connections. A circuit that melts at slightly above ambient might be of limited use in practice, but if it wets at those temps it would provide superior conductivity for a video shoot and all you had to do is heat the pcb to like 30 °C.

[@hashdankhog8578]

If it would be possible to develop an add on so the lumen would squirt out the adheisive as it put on components this would be absolutely killer for rapid prototyping. Imagine designing a pcb, milling it, then putting it on this to get a fulling functioning board. And when you are done designing you swap to regular solder paste.

[@dennisolsson3119]

There are conductive 3d printer filament. If you can find one you can dissolve you might be able to create a paste you have more control over its drying time and how gluey it is. Maybe even an UV curing one for resin printers?

[@BrentLeVasseur]

That’s cool, but if you have to manually put the ink solder on the board then it kind of defeats the automation of the robot. So what you need to do is make the robot deposit the solder on the pad first and then place the component part on the board.

[@sadiablo]

Maybe try having two part glue with spray activator, one part with graphite and spray it with second part after finishing job? First part should be conductive enough so that it works while on Lumen and for mechanical strength you would use activator

[@TrebleWing]

I've experimented with silver paint, it has a bunch of real silver in it and it's honestly respectably low resistance. Only issue I had for my application is that it's pretty thick compared to the carbon paint

[@rklauco]

It would be interesting to mix the black carbon powder with actual solder paste, then use it "normally" as paste and spread it across the board. Idea is - the carbon would cause it to conduct before melting, but then you can normally reflow it, getting "classical" PCB workings.

[@JoshuaLawson-k2l]

A issue with adhesive based interconnect is reliability over time in terms oxide creep on plating on part connections , depends on environment conditions. For prototype is all ok

[@wooviee]

I might try this for prototyping a PCB, awesome idea!

[@jgooding213]

you can get conductive glue which contains silver for mounting back biased silicon chips like sensors :)

[@larsfroelich]

I think you're really onto something here! What if you could extrude this stuff with a seperate application actuator on the PNP right before placing a component? The "stencil time" would be reduced to below 5 seconds! This would eliminate two manual manufacturing steps, applying the solder paste and the reflow oven. The whole point of the PNP is to make small-scale manufacturing affordable, so the fewer manual steps are required the faster a single person could manufacture PCBs with the lumen.

[@EMleRoux]

Add a hot plate to the LumenPNP, maybe even a solder dispensing pen. Place components on heated pcb and let the surface tension do the rest. Look at me telling you about things you've probably already thought of. - How well does molten solder conduct electricity?

[@KarlMiller]

@TechIngredients made a thermal epoxy that might provide some ideas for making a electrically conductive epoxy that might be tweaked to get the right characteristics that would make it useful as a solderpaste of soets. Also, I was thinking about an INDUCTIVE heating wand that could be mounted on the lumenpnp like a toolhead for melting placed components using regular solderpaste.

[@OMNI_INFINITY]

*Nice! Sitting in shenzhen now (not chinese) and glad I forced Myself to rest after doing embedded coding past midnight. I plan to look on taobao to see what z-tape solutions are available and try at least one of those. So tired of soldering 16 pin USB connectors, and most of the 6 pin connectors on taobao didn't have data lines, so z-tape is a lower cost solution than PCBA. Would like a pick and place, but it has to be smaller and lighter weight for luggage. Already travel with some of a portable factory (that is thankfully small enough to be strapped on both arms if I want to)...LOL.*

[@nirani9721]

This is so cool! Thanks for posting! Just wondering if you tried placing the component first and then applying the paint to the pad/component termination?

[@Freakingsstein]

Check Panacol, they have a bunch of conductive adhesives that might do what you want. The Elecolit 3036 is a 2 component epoxy that can cure in room temperature or an oven (normal oven is sufficient) Though I am not sure how expensive is it for low quantity consumers.

[@patregan]

Nice work, Stephen! It looks like you found a way to make some awesome b-roll for the LumenPNP v5 intro video!

[@Falney]

Conductive adhesives actually already exist and they are typically epoxy or silicone based. But they are also about 10x the price of solder paste

[@OhHeyTrevorFlowers]

Ok, the first working example was cool. What a fun idea!

[@VoidStriker1523]

There are tons of conductive epoxies. Typically will use some special epoxies in hermetically sealed packages or for die attach. Snap cure UV materials exist as well

[@h1tec]

I wonder if this could be used for flexible circuits which can’t handle the temperatures required for even solder paste. Great job as always 👍

[@aerispalm6523]

used conductive silver glue from aliexpress a while back for an electronic postcard, where i wanted to connect 2016 cells in the lowest profile way possible(sandwiched in between a flex pcb). maybe that's something to look into

[@MiShO10O0O]

I think it will be way better if you dispense solder paste from the Lumen instead of a conductive ink, would speed up prototyping a lot!

[@StreuPfeffer]

since there are two nozzles on the head, have one of them be a Syringe that can dispense things? Problem is to have it consistently only drop a bit of paste/ink/liquid across teh whole syringe. And probably need to remove the pressure a bit so it doesn't drip while moving across the board for the pnp part of the job. some machines do have glue dispensers for upside down wave soldering? (iirc)

[@MiShO10O0O]

​@@StreuPfefferThere's also an extra GPIO in the V4 head... opens up more possibilities! but yeah def. not easy

[@EndlessRaidApp]

Seems like you could take this idea further, and buy one of the monochrome LCD resin printers, and 3d print some little pcb offset for the resin vat, mix the graphite into some 3D resin with decent pigment holding which isn't uncommon in the space, then you'd be able to just blast a conductive resin circuit design on a substrate. You can then make a thick UV activated epoxy to dispense as the solder, can mod a 3D printer or get a automated glue dispenser, "bake" under UV light and you'd have a whole setup at home PCB prototyping setup with Lumen.

[@christianbaumgartner7133]

I have already tested UV Resin mixed with Lamp-Black, but it gets so dark, that the UV-Light can’t get deep enough and only a very thin „skin“ gets hardened!

[@EndlessRaidApp]

@@christianbaumgartner7133 Ah, yeah, that's a very good point. Perhaps, Indium tin oxide powder might work better?

[@ChefBenni]

Quite easy solution, build a dispenser into your pnp head ;-) I think everybody here knows where this is going and it‘s needed. Even if you place the paste with a stencil, glue placement alsways needs to be made with a dispenser. If you could make a double dispenser head into the pnp head, you could place the paste and glue within one job.

[@highvis_supply]

This would be fire for showfloor demonstrations

[@innocentquasimodo]

Very interesting. Did you consider to try "Silver Nano Ink and Silver Nano Inkjet Media" ? You can even print your own circuit boards. Thank you for this cool video.

[@AJMansfield1]

What about a syringe-dispenser head for the PnP itself? Not just for this, but for dispensing paste for other applications too. E.g. pre-soldering config-specific ID jumpers in addition to the baseline masked paste layer.

[@joepartlow]

Conductive epoxy may be what you're looking for. Check out Epoxy Technologies and Loctite Ablestick. They both make silver filled conductive epoxies the can be oven cured at temperatures from about 80 degrees C to 200 degrees C and are made to be screen printed like solder paste or dispensed from a syringe.

[@michaelpedersen5965]

Could you extrude paste, place, then (once done) add a conformal coating to 'seal' the board so it is more durable?

[@LimbaZero]

Maybe some ink head for that machine that put some ink to pads just before placing components. Then you can use that more fluid ink. Edit: Maybe ink nozzle size need to be enough small to do smd ic solder pads. Maybe around 0.1mm and also the pump need to be accurate for small volumes.

[@michelbrasseur9296]

Does ultrasonic welding might works just as wirebond soldering, might worth a shot for fun 😊

[@marshallsober]

Man you should add your own UV/hardened conductive resin with the lumen head over the pads and the part you need to figure out the right product as surface tension and viscosity is a huuge factor here but looking for an idea better than the stencil and the paste i think UV resin is your next try you kind could add a solvent too make it more runny but yeah this whole process could all just be the dual head of the lumen applying paste and then cooking the board as someone else mentionned but you also could try some other stuff

[@MrBlakBunny]

this would be awesome for prototyping test builds, in general

[@alexkrause7285]

I worked at Apple - some modules use Z-Tape type connections. Getting good even pressure and strong reliable connections is an endless optimization game.... but yes its in 100 of millions of parts!

[@Robothut]

UV clear resin mixed with conductive powder should do the job, as you have all the work time you need before you cure it with UV light.

[@bobcov-j2w]

Fantastic content and talent. I just wish there was a service to provide narration in a calm voice. I watch with subtitles and no sound.

[@sarchlalaith8836]

You should message Robert murray Smith, he makes conductive graphene ink and paint

[@craigrotay3732]

Can your pick and place machine dispense the paint right before component placement?

[@solveit1304]

Imagine Opulo with solder paste surringe and laser. You could first apply paste, then parts and finaly laser it for melting solder paste. That would be sick, but kinda hazard for eyes 😅

[@sebstardoo]

Heyoo, UV CURING EPOXY MIXED WITH GRAPHITE POWDER 🙏🙏🙏

[@youssefhamid6772]

Hey Steven, can you create an adhesive dispense machine? utilising the vision system of the lumen?

[@phillipj1135]

a guy named Robert Murray smith has a bunch of videos on conductive ink and various methods of preparing it if you want any inspiration. using a mix of different size carbon helps with conductivity.

[@dtec30]

Wondering if you can combine them ie a tape with holes and then drop In the conductive gel where the component is

[@timprapotnik7951]

Have you ever thought of using a SLA printer to make the entire pcb in house (I once saw it done on a 3d prining channel - thomas sanladerer). Though he did etch it so I'm not sure about the safety of the chemicals... Would be interesting to see if you can 3d print the solder mask though.

[@dirtdart81]

A stencil and hotplate is just so easy. Or even just place the paste manually for small boards. A new way would have to be incredibly simple to be a plausible iption

[@BRUXXUS]

This is cool! It does make me wonder... is regular solder paste conductive without melting? Surely some of them solder balls are making contact when a part is squished down? 🤔Might be worth a try!

[@ravplayztabla7467]

u can just buy conductive glue. this is used in flexible pcbs instead of solder

[@SianaGearz]

The suspension liquid (rosin+solvents) prevents solder paste from conducting all the way through, too many opportunities for continuity to break. Fun fact, grey thermal paste is not always but quite often only aluminium particles suspended in silicone, with most of it being metal. Also not electrically conductive, not even under pressure. In my mind all of these suspensions should theoretically act as a capacitor, so one could try driving the LED with a couple MHz, but i have my doubt that it's going to do anything.

[@SianaGearz]

Do keep in mind Z-tape is not a suspension. It's a thin sticky carrier with hollow spheres embedded into it, where each sphere spans the whole thickness of the tape and then some. When applied correctly, the sphere changes shape, with some probability creating a single conductive column that pierces all the way through. It's not even very conductive, and it already took a lot of engineering beyond basic suspensions to get it that far.

[@BRUXXUS]

@@SianaGearz Oh! I somehow didn't know the spheres were hollow, but that makes a lot of sense. And yeah, I think these are all mainly for just signals vs power since there's so little surface contact. Now I wonder if someone could make something like ZEBRA connectors in a 2D plane. Like fine checkerboard of alternating conductive and sticky squares. Might be fun. :)

[@chopper3lw]

Maybe a UV cured adhesive with conductive additive? You then have all the time in the world and can selectively expose it with the placement head.

[@HorochovPL]

PCB with stenciled soldering paste on a hot plate, keeping the soldering alloy in a liquid form?

[@mariovano]

Definitely food for thought!

[@sud9320]

Crazy overengineered idea: have PCB, with solder paste applied, on a hotplate while placing components and flood the machine with nitrogen so the solder doesn't oxidize.

[@AMTunLimited]

I wonder if you could squeegee the electric paint over the solder mask like paste?

[@SwapPartLLC]

I'm guessing you have anisotropic conductive film. It is used in a process called tape automated bonding (TAB). This is how flex cables are attached to LCD displays. It's also used for chip on flex (COF). You can't just stick components to it. You need heat and pressure to make a bond.

[@Chino-dy4ib]

just add a mod for the lumenPNP, add a small injection tube slot that applies the paste before placing the component, that would just make the manual application unnecessary.

[@Chino-dy4ib]

i would not be surprised if there are people out there that would want this, this just means you need less tools for prototyping.

[@AdityaMehendale]

Do you plan to dose the "ink" with the lumen, eventually?

[@Corebb]

Looks so fun!

[@shagreobe]

That stuff is crazy! what are they going to think of next

[@fpfree8821]

If the green solder mask were thicker therefore noticeably higher than the pads solder paste could be squeegeed over the whole board without the need for a stencil