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Conducting Filament

Posted: Wed May 03, 2017 5:20 am
by jerteach
Almost done getting used to the N2 printer. Just did my first dual extrusion. Worked nice. My plan is to have my students make some 3D Prints with conducting PLA and test the resistance within the model.

If I replace the yellow in the following image with black conducting filament I want the filament to have full infill, however I think you can only set infill for both extruders. Any suggestions how to set infill at 100% for only one extruder and the default 10% for the other?

dualinfil.png
dualinfil.png (9.46 KiB) Viewed 2183 times
dual02.jpg



The above print looks fine, but the below print shows only 10% infill with the yellow, which when the yellow is replaced with conducting filament will not conduct as well than if it is solid. Any suggestions? I guess the solution is to make both extruders 100% infill.

dual01.jpg

Re: Conducting Filament

Posted: Wed May 03, 2017 7:15 am
by Vicky@Raise3D
Not familiar with conducting filament, but if you want to increase the infill of one nozzle, you need to increase the other one together.
The currently ideaMaker doesn't take this setting apart for two nozzles.

Normally when fill density over 60%-70%, it is almost like a solid part.

Re: Conducting Filament

Posted: Wed May 03, 2017 12:04 pm
by walshlg
yeh conduction isnt very good and is proportional to cross-sectional area

Re: Conducting Filament

Posted: Thu May 04, 2017 7:37 pm
by tja
As Vicky has pointed out, IM applies the same infill percentage to both extruders. The easy fix is to set the infill to 100%, but another trick might be to play with the number of shells. I just printed a part with 5 shells and the effect was that the small section areas were effectively printed solid, whilst most of the thicker sections were filled at the infill percentage. This may work for your model.

Why are you using a raft? With the time and filament you are putting into the raft, you could print the item at 100% directly on the bed and save both.

Please let us know how you get on with your conductive filament experiments. From what I have read, the resistivity is quite high, even on the so-called 'low resistivity' filaments,

Re: Conducting Filament

Posted: Fri May 05, 2017 4:39 am
by jerteach
tja wrote:I just printed a part with 5 shells and the effect was that the small section areas were effectively printed solid, whilst most of the thicker sections were filled at the infill percentage. This may work for your model.



Thanks tja, that is a brillant suggestion, I will try that when the ProtoPasta conductive filament comes in.

Most of the conductive inks etc that I have tested so far have not been very good. I will post what I fined out. The chance to have my students make little LED embedded devices is too cool to pass up. P.S. Most LED's need some resistance, just not too much ;)

The reason I use the raft is that my builds seem to attach better, I am also a bit scared of wrecking my BuildTac with a hard to remove print. I guess I could always crank the bed temperature up if I can't remove the print. Any other suggestions.

Re: Conducting Filament

Posted: Fri May 05, 2017 12:16 pm
by walshlg
Another idea is to design the fill yourself as part of your model.

Re: Conducting Filament

Posted: Sat May 06, 2017 4:16 pm
by jerteach
walshlg wrote:Another idea is to design the fill yourself as part of your model.


I use Blender which is fairly difficult since it is mainly for animation not 3D Printing and is difficult to make objects manifold for 3D Printing. Are you suggesting I make the object have it's own layers or inside columns? See image.

columns.png




I think that would work especially if I combine it with the other shell suggestion.

Thanks walshlg

Re: Conducting Filament

Posted: Mon May 08, 2017 12:10 pm
by walshlg
yes but personally I like the fill at 45 degrees so it intersects the walls making it stronger. Just make a cross hatch design and do a boolean intersect, ( you may have to put on a temporary lid).

Re: Conducting Filament

Posted: Mon May 08, 2017 8:40 pm
by jerteach
My conductive protopasta filament arrived today. Here are some images and my Ideamaker settings file using the left extruder for the conducting filament and the right extruder for the regular (insulating) PLA and raft.

My Exported and zipped Conducting Filaments IdeaMaker settings.
conducting-export.zip
(4.75 KiB) Downloaded 21 times


Note: When removing the Conducting filament I had to load regular PLA for a long time to get rid of the black shade.



Using a 25 mm cube, with an interesting structure of tubes inside it.


Testing a 5.1 K ohm resistor
5.1.jpg



Horizontal with 90 degree angle 3.25 K ohm

angle.jpg


Straight horizontal 1.24 K ohm
horizontal.jpg



Straight vertical 2.50 k ohm
vertical.jpg

Re: Conducting Filament

Posted: Mon May 08, 2017 8:44 pm
by jerteach
More images



The filament about $20 CDN

conductive_pla_grande_17a8b2f9-b407-43cd-b298-58c7dd4a4c8b_1400x.jpg


The cube with internal structure

general-image.png



Printing

printbed.jpg


Wipewall

wipewall.jpg


LED working but not very bright.
LED.jpg

Re: Conducting Filament

Posted: Mon May 08, 2017 9:37 pm
by Ari
An interesting experiment.

Given current progress in the technology of conductive filament I think that is not too bad a result. Perhaps to better demonstrate the concept to your students you could increase the voltage to make the LED appear brighter. Some of the later type LEDs are quite bright when forward biased with around 10mA. Using a small 12V battery for example might be better for demonstration purposes.

With the resistance values you have measured and the appropriate supporting electronics, this filament opens up many possibilties for practical use, resistive touch sensors for one.

Thanks for sharing.

Re: Conducting Filament

Posted: Tue May 09, 2017 12:29 am
by jerteach
Ari wrote:
With the resistance values you have measured and the appropriate supporting electronics, this filament opens up many possibilities for practical use, resistive touch sensors for one.


Great idea. I think there might be lots of things the class could do.

I found a link on thingiverse http://www.thingiverse.com/thing:1655695


and another that looks interesting
http://www.3dprintmakers.com/shop/testshop20140111/item/touch-sensor---cost-effective-displacement-type

This water one is strange
http://www.3dprintmakers.com/shop/3d-print/item/ufluid-chip-experiment

Re: Conducting Filament

Posted: Tue May 09, 2017 4:08 pm
by walshlg
I strongly suggest that you give annealing a try, it might improve conductivity a lot

Re: Conducting Filament

Posted: Wed May 10, 2017 6:05 am
by jerteach
walshlg wrote:I strongly suggest that you give annealing a try, it might improve conductivity a lot


I like the idea of after printing covering the object and raising the printbed to about 80 C, then reducing the print bed temperature over a few hours to room temperature. The other idea is to anneal in the oven but once it is removed from the printbed expect warping.

Curious if the resistivity will reduce. Any other suggested temperatures and durations for annealing?

Re: Conducting Filament

Posted: Wed May 10, 2017 4:18 pm
by walshlg
annealing with PLA is touchy from what I read, 80C (you need to be above glass temp) for 4 hr worth a try, check out vid from Sandladder

Re: Conducting Filament

Posted: Wed May 10, 2017 9:57 pm
by jerteach
walshlg wrote:annealing with PLA is touchy from what I read, 80C (you need to be above glass temp) for 4 hr worth a try, check out vid from Sandladder



Can you throw a link to sandladder not sure how to find it.

Re: Conducting Filament

Posted: Wed May 10, 2017 10:05 pm
by jerteach
So I tried annealing for only a few hours. Build plate at 110 C, glass cup upside down over the print. Got the PLA to about 60 C and the Conducting to about 75 C. Then let it cool over half hour to about 45 C and tested the resistance. Seemed to reduce all resistance by about 600 ohm.

I did not feel like this was anywhere near long enough, but reasonably impressed with the reduction in resistance. Contacted Protopasta to see if they have any temperature suggestions. I will do a bit more testing with an oven on the weekend.

Re: Conducting Filament

Posted: Thu May 11, 2017 1:24 pm
by walshlg
OK here is an idea, perhaps if you annealed with current going through it would reinforce the conductive pathway!! Try inserting something like a spade plug and anneal with maybe 100mA and see if that improves conductance! Might be a waste of time but might not!

Re: Conducting Filament

Posted: Thu May 11, 2017 3:47 pm
by jerteach
walshlg wrote:OK here is an idea, perhaps if you annealed with current going through it would reinforce the conductive pathway!! Try inserting something like a spade plug and anneal with maybe 100mA and see if that improves conductance! Might be a waste of time but might not!



:D


Someone better with electricity than me might want to look at this. Could we just use electricity to heat the conducting filament and then really slowly let it cool? Not quite sure of voltages or currents that would work, but I try to keep my Robotics class assignments below both 12V and 2 Amps for safety reasons. I am fairly sure 120 V is a really bad idea.

Sounds like a Physics 12 problem:

How many joules of electrical energy will raise the temperature of 3 grams of Conductive PLA from 25 C to 100 C given that the Thermal Conductivity for normal PLA = 0.13 W / m K. Assuming the resistance is 2000 Ohms and you must use a voltage that is reasonably safe.

I think I am just going to see how hot I can get a 2K resistor.

...

That was interesting at about 17 V DC it just kind of went brown, but the outside did not register much change with my IR thermometer.

Seeing if I can get help from the particle.io Robotics forum https://community.particle.io/t/annealing-conducting-filament/32662

...


I tried about 30 V DC for a few minutes and got about a 2 degree rise in temperature.

Just got an email from Protopasta saying the conductive filament does not anneal.

Re: Conducting Filament

Posted: Wed May 17, 2017 5:11 am
by jerteach
Posting most of my Raise3D Conductive filament printed images at

https://community.particle.io/t/protopa ... on/32712/4