I am going to make a 3d printer which can print PCBs. I would like to ask you what it must be capable of to be of use to you. So far we have come up with these:
The time it takes to print a PCB should be within a reasonable amount of time.
People with basic knowlegde of electronics and programming must be able to use it with reasonble ease.
The maximum voltage of the PCBs must be 5V or more.
The PCB should have reasonable temperatures during the printing process
The printer must also be able to print the materials a normal 3d printer uses.
Please note that were students and that we dont have acces to a unlimited amount of money.
At this moment, we want to print solder on a non conductive material, because it has a meltingpoint between 200 an 250 °C and a low resistance. With the solder we want to print tracks, just as on a normal PCB.
I will definately have a look at that, thank you for the tip.
We wanted to solve the problem of soldering the components on the pcb by letting the printer do it, so just taping them to the upper side of the pcb and letting the printer solder them while he is laying the tracks of solder on the bottom side. But maybe this problem is solved with the copper powder.
... another related idea (discussed some 5+ years ago) is to place the electronic components (and nails/pins) backside down onto a printed plate (top housing part), print/fill the gaps between them with plastic (mainly for stability), then use the stone-old "wire-wrap" technique (with soldering assistance) to draw wire connections between the pins, and last cover/close the wire layer with plastic to get a stable basis or even the bottom housing part, so the complete module will be ready to use, when removed from the print bed
It is definately a smart idea, but I'm not sure if its the perfect idea for us. What we want is to make it less time consuming for the custormer. This is definately a way to do that, but you're other idea, with the copper powder and the laser, is less time consuming.
There is some potential here but a LOT of challenges. Probably the biggest one is that solder isn't attracted to plastic. It takes flux just to get it to stick to metal. Maybe a flux impregnated substrate would work but I wonder what the costs would be to the end user. Another problem is that most PCBs are at least two layer. You would have to figure out printing vias. Although, if you can figure out how to allow two traces to cross you might be able to put everything on a single side. I could see using a dual extruder, one with conductor and one with an insulator. Another problem is about accuracy. While zits, blogs and other errors are ok with a simple print, there is no tolerance for that - a lot semiconductors have leads that are .5 mm apart. I'm not sure what the max nozzle size would be but I bet it's at most .25mm.
But why are you using solder at all? It's not a terribly good conductor and you can get conductive plastic. For a large class of application, you don't need much current capacity at all so conductive plastic might be fine.
And what's stopping us from attaching a small paste extruder to our printer and print the PCB with silver ink with the same technique as the product in your link ? It's already working, the silver ink is sticking well to the PCB and after drying, you can solder your components manually or even lay solder paste with the printer itself if you work with SMD components.
The silver ink paste extruder will have to be small and precise, but nothing impossible to achieve ! The 0.2 or 0.3 airbrush nozzles are perfect for laying down the paste as they don't smear or flatten it.
... if you find old infos about the [email protected] project (started at same time as RepRap, but didn't get same attention) -- they used dispensers instead of extruders and too tested "printing" with conductive pastes to create PCB's.
I'm using "jetting" dispensers for glues and solder-paste too ... but it's pretty pricey, so not suited for DIY
Here a sample, printed with solder paste on paper:
I like the idea very much and it reminded me on what I found at a german company called "Multec" and I liked the idea of integrating this in my designs to let away the cables. I hate cables.
They sell or sold conductive PLA, at the moment it is not available - perhaps there are others that can deliver similar filaments? Did not do a research in this.
Two thoughts on this:
1. Have you seen CNC PCB milling machines? A lot of similarities: but they are subtractive, rather than additive.
2. Conductive Epoxy is starting to make inroads into commercial PCB technology instead of solder. This might be a better medium to print with.
To be frank, you've got no chance of 3d printing solder and getting it to stay put: solder is sociable: i.e. it prefers the company of other solder. Although you could easily jet out solder paste, the moment the board is heated, it'll gloop together and break your tracks.
I am experimenting with printing PLA, two layers, on a full copper top PCB and etching away everything that is not covered by the PLA. Seems to work, but getting the PLA to grip to the copper is not easy. I rough the copper with fine sandpaper (1000 grid) and apply hairspray. It sticks during printing, but it sometimes comes loose during etching.