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richnormand
(@richnormand)
Eminent Member
Electrically conductive PLA

Has someone tried to use electrically conductive PLA to make custom sample holders for use in a SEM (scanning electron microscope)?

In particular effects due to outgassing or conductivity been any issues?

Just got a spool from Protopasta from the US to try but I do not want to mess my MK3S or the SEM.

Cheers and thanks.

Rich

REPAIR, RENEW, REUSE, RECYCLE, REBUILD, REDUCE, RECOVER, REPURPOSE, RESTORE ==> RIGHT to REPAIR...
Posted : 18/09/2021 1:36 am
jsw
 jsw
(@jsw)
Noble Member

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.

Posted : 18/09/2021 11:26 am
richnormand
(@richnormand)
Eminent Member
Topic starter answered:

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!

REPAIR, RENEW, REUSE, RECYCLE, REBUILD, REDUCE, RECOVER, REPURPOSE, RESTORE ==> RIGHT to REPAIR...
Posted : 18/09/2021 4:00 pm
jsw
 jsw
(@jsw)
Noble Member

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.

Posted : 18/09/2021 10:50 pm
bobstro
(@bobstro)
Illustrious Member
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.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 19/09/2021 2:42 am
cwbullet
(@cwbullet)
Illustrious Member
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.

 

--------------------
Chuck H
3D Printer Review Blog...
Posted : 19/09/2021 11:08 am
jsw
 jsw
(@jsw)
Noble Member
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.

 

Posted : 19/09/2021 12:41 pm
cwbullet
(@cwbullet)
Illustrious Member
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.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 19/09/2021 12:43 pm
Diem
 Diem
(@diem)
Noble Member

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,

Posted : 19/09/2021 3:25 pm
cwbullet
(@cwbullet)
Illustrious Member
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.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 19/09/2021 3:32 pm
jsw
 jsw
(@jsw)
Noble Member

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

Posted : 21/09/2021 9:52 pm
richnormand
(@richnormand)
Eminent Member
Topic starter answered:

@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....

REPAIR, RENEW, REUSE, RECYCLE, REBUILD, REDUCE, RECOVER, REPURPOSE, RESTORE ==> RIGHT to REPAIR...
Posted : 21/09/2021 11:20 pm
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