Electrically conductive PLA  

I haven't tried it, but I'm intrigued by the concept of being able to lay down conductive circuit board patterns on a 3d printer.

Although I have not looked at this for several months, my impression is/was that the best conductive filament still has a resistivity that will translate to kilo-ohm resistance on a typical printed trace.  This may be ok for slow-speed logic and very low level analog, but not for currents even in the milliampere range or for logic where the delay and distortion of the trace resistance and the stray capacitance will be significant.

Thanks for the feedback jsw.

Indeed the resistivity is high for applications requiring any sort of electronics.

In the SEM I assume this is OK as the goal is to avoid electrostatic charging of the specimen. I am presently changing the printer nozzle as this stuff is abrasive and made a few SEM stubs designs with side-clamps that would allow quick changes for the samples. If this prints well I can then fit several tens of those on the heatbed and have enough to last me months!

Your application sounds more like you want to make a somewhat-conductive substrate, as opposed to using 3d printed filament to power devices or control logic, so you may indeed be on the right track.

If you are just going to use it to hold a sample at a particular potential, with no appreciable current draw, the resistivity/resistance may be a non-issue for you.

Specialized filaments

There are specialized filaments with low conductivity.  Unfortunately, what I've read about conductive filaments indicates that 3D printing circuit boards is not yet practical. I haven't tried some of the newer conductive claims, but the stuff is not cheap.

circuits.

I researched this 2 months ago and found that 3d prints would not meet my requirements and it was cheaper to just go with Osh Park made boards.  

Posted by: @bobstro

There are specialized filaments with low conductivity.  Unfortunately, what I've read about conductive filaments indicates that 3D printing circuit boards is not yet practical. I haven't tried some of the newer conductive claims, but the stuff is not cheap.

Posted by: @bobstro

I haven't tried some of the newer conductive claims, but the stuff is not cheap.

Thanks for the pointer Bobstro.

The stuff at https://www.multi3dllc.com/product/electrifi/ is actually very close to what I would want, even though it's quite expensive.

For US $200 for ~17 meters, that would actually be cost-effective for laying down traces that are measured in ohms instead of kilo ohms.

It looks like you can 'solder' the traces to wires and components by using melted filament.

They have a comparison between their product and the ProtoPasta and a Black Magic 3d product.  The trace with ProtoPasta measures ~1500 ohms, the BM3d trace measures ~142 ohms, and theirs measures 3 ohms.

That would make such a product practical for circuitry where high current, higher speed logic, and low noise would not be requirements.

I'm definitely bookmarking that site in case I decide to try something like this.

It's a very low temperature filament.  I envision first laying down a 'board' of PLA or whatever, then doing a manual filament change to the conductive filament for the traces.  I assume that it will stick to warm PLA or whatever.

Of course at that price I would be doing test prints with another filament to be sure everything is just so before using the expensive product.

I would hope that the price point lowers as the market settles and maybe more competitors enter the market.

use

Posted by: @jsw

Posted by: @bobstro

I haven't tried some of the newer conductive claims, but the stuff is not cheap.

Thanks for the pointer Bobstro.

The stuff at https://www.multi3dllc.com/product/electrifi/ is actually very close to what I would want, even though it's quite expensive.

For US $200 for ~17 meters, that would actually be cost-effective for laying down traces that are measured in ohms instead of kilo ohms.

It looks like you can 'solder' the traces to wires and components by using melted filament.

They have a comparison between their product and the ProtoPasta and a Black Magic 3d product.  The trace with ProtoPasta measures ~1500 ohms, the BM3d trace measures ~142 ohms, and theirs measures 3 ohms.

That would make such a product practical for circuitry where high current, higher speed logic, and low noise would not be requirements.

I'm definitely bookmarking that site in case I decide to try something like this.

It's a very low temperature filament.  I envision first laying down a 'board' of PLA or whatever, then doing a manual filament change to the conductive filament for the traces.  I assume that it will stick to warm PLA or whatever.

Of course at that price I would be doing test prints with another filament to be sure everything is just so before using the expensive product.

I would hope that the price point lowers as the market settles and maybe more competitors enter the market.

 

Very interesting product.  I can see where it might have a very limited use.  

For US $200 for ~17 meters, that would actually be cost-effective for laying down traces that are measured in ohms instead of kilo ohms.

It might be of use for rapid prototyping but incorporating a mini breadboard within a project would be more flexible.

I can see the attraction for three dimensional circuitry or studding components around a non-flat surface but every filament change would lose an expensive length of scrap. An MMU would waste loads, especially as extra purging might be needed to prevent trace currents in what should be insulating intertrace areas.

It might work for point to point connections with a 3D pen - but soldering old fashioned wire is slightly less hassle.

I don't see it replacing pcb's or even stripboard at the moment, maybe if economies of scale bring the price down by an order of magnitude.

About the only genuine use I can think of is bespoke resistive sensors, touch sensor pads and the like.

Cheerio,

Circuits

I got 12 circuit boards printed for less than $23 shipped for a prototype continuity checker.  All twelve were soldered and assembled for less than $50.  I can see the use in prototyping, but It can still be cheaper from Osh Park.  

On a related note, this hit the inbox a while ago, development of 3d printed copper windings.

https://www.fabbaloo.com/news/exone-and-maxxwell-motors-partner-to-design-3d-printed-copper-windings

@jsw

that looks interesting indeed.

To go back to my issue I now have everything setup to go forward. I have a nice design in Fusion that looks like a standard SEM stub at the bottom and a clamp on top for the samples. I found several references that imply that PLA is generally OK in medium vacuum, including a NASA outgassing study.

As far as electrical conductivity the higher resistance is not much of an issue as the goal is to avoid an electrostatic charge buildup while being scanned by the electron beam. If the buildup gets too high the beam gets deflected or even repelled thus creating  black voids in the image and surroundings. However the beam current is pretty low. 

Will post results when I try it.

Thanks for all the great feedback from everyone. In particular the better conductive PLAs that might come in handy considering the weird projects I get involved in sometime.

Note to self: gotta learn to say no sometime.... but curiosity and learning something new always seem to win....

RE: Electrically conductive PLA

Just to update.

I have been using the conductive PLA from ProtoPasta for several weeks now. I made customs sample holders for use in my scanning electron microscope (SEM). They have to be electrically conductive to avoid charging effects from the electron beam so low resistance is not a requirement but they should be conductive. For example the little rectangle at the end of the first layer Z adjust on my MK3S measures about 3 kilo-ohms.

I was worried about outgassing but that does not seem to be an issue (at least for the ProtoPasta but check if you use a different manufacturer). As well, doing EDS on the holders showed the expected carbon as well as small assorted metallic particles.  So, overall, nothing to worry about. I printed them with 50% fill.

Changed the nozzle to 0.4 tungsten carbide and I did not have to readjust anything since it looks like the thermal conductivity is similar.

Hope this might be useful to someone else.

Cheers

RE: Electrically conductive PLA

Maybe a little late to the party but this material might be of interest:

https://addnorth.com/product/Koltron%20G1/Koltron%20G1%20-%201.75mm%20-%20100g%20-%20Black

Never used it myself but I've been printing solely with their other materials last three years. High quality manufacturer, and theres ready profiles in slicer for their materials.

RE: Electrically conductive PLA

Hi AndersK.

Specs look interesting indeed, thanks for posting the link.

I will contact them and see if they have experience with outgassing issues in vacuum. The rest of the specs look very usable indeed.

The only problem I see is the price, not being in stock and shipping compared to what I am using.

RE: Electrically conductive PLA

A call to them can help, supplied me more than once even if out of stock on website.

Shipping, well I have the luxury of being 40 minutes away from them 🙂

RE: Electrically conductive PLA

Thanks for the link, Anders.

At a stated resistivity of 2 ohm*cm, doing some imprecise math in the head, the typical trace that would be laid down with a 3d printer nozzle will have significant resistance for any appreciable length.

There was another product cited earlier that claims to have resistivity way down in the three-figure fractional range.