First Test of the Conductive 3D Filament

One of my favorite things about 3D printing as a hobby is that new capabilities are developing almost daily.  It seems like a new type of filament is on the market every day, or someone has assembled a new extruder to do anything from create edible cake decorations to pouring concrete housing.  A while ago I ordered [STAR] Alchement's Conductive ABS filament and this week I started testing it out.  The significance of this as a printing capability is pretty obvious.  If you've also got an interest in electronics, it's possible to simply print some circuitry as opposed to leaving cavities for electronic parts in your prints.  My dual extruder printer should be particularly well suited for this -- print regular ABS from one extruder for the main print, and conductive from the other to make "wires" through the print.

Of course, this all depends on whether or not the conductive filament is truly conductive.

The Amazon reviews aren't promising.  To date there's one question asked: is the filament truly conductive?  One person has answered, and he rather vehemently says no, it's not conductive at all.  Likewise, the sole review gave the filament three stars and claims that it's not conductive "by any means." 

Well, I've got a roll and I like Alchement's other filaments, so let's give it a try.  Here's my disclaimer: I've only run one test so far.  I'm going to modify some of the prints to see if I can improve the results.  I wouldn't claim that this first bit of data is conclusive.

For a simple conductivity test I printed a little connector, pictured to the right.  It's just a rectangle of filament, 40mm long, 2mm sides.  The final 10mm at each end is a hollowed out cone, 1mm wide at the very end, narrowing down to .4mm.  Hence, a jumper wire or the leg of an LED or resistor pressure fits into the socket and there are 20mm of "solid" filament between the two sockets.  (Quotes around "solid" because I printed this at 50% infill.  One of the next things I'll toy with is printing the "wire" at 100% infill.)

Quick printing specs: because I'm dealing with a pretty small part and want the sockets to work well I changed my primary layer height to .1mm.  The bed is set at 105C and the extruder at 230C.  It printed quite nicely at these settings and given how small the part is, it took about 10 minutes.)

Time for some measurements.  The picture on the left is the multimeter hooked up directly to the 9V battery.  Not surprising, I'm getting just under 8V.  (It's a veteran battery.)  On the right, I've gone from the battery to my filament connector, then a jumper wire to the multimeter probe.  Noticeable drop in voltage, down to 4V, but it IS conductive.

Some immediate thoughts: it's possible that my socket design isn't the best.  The wires are all plugged in pretty tight; they won't fall out of the sockets without a good tug.  It's worth looking at, though.  Also, the aforementioned infill of the wire.  In the current configuration (no pun intended) my "wire" is 4 square mm with 50% infill.  When printing this as a wire inside another model I plan on making the wire a 1mm cylinder at 90% or 100% infill. 

Of course, the multimeter is good for testing but not really a fun application.  Here's a little more visual evidence of the difference, using an LED to demonstrate.  Again, straight hookup on the left, conductive filament socket in the mix on the right.

Early conclusion: hell yeah, it's conducting electricity!  No disappointment here, it's time for more experimentation.  :)

Dialing In My Frustrating Frustum

Yesterday I decided it would be fun to create a 3D model of a pyramidal frustum.  I have no idea how this popped into my head, but I've decided to blame it on my friend Mike P., from way back in junior high and high school.  Mike had a great knowledge of the esoteric and was quite a good artist.  It's quite possible that while we were playing Car Wars one day he made an offhand comment like, "If I designed a house it would be a pyramidal frustum."  That'd be just like Mike.

So yesterday I decided to model my own pyramidal frustum, and because no project can be left simple, I decided to embed Fibonacci spirals in the faces.  (Plus, anything with a Fibonacci spiral is automatically +5 in Mysterious, right?)  You can see the OpenSCAD code for the modeling if you like, but here I'm going to talk about dialing in the FlashForge Dreamer settings to make a nice print.

The four prints in the photo are ordered left to right from first printed to final print.  The first print's pretty bad.  The copper layers are really uneven and the edges are stringy. The blue spirals look terrible -- the second extruder leaked blue filament everywhere, yet somehow managed to not fill well in the print itself.  Go figure.  I'm using Simplify3D to slice and in that first print, the Hatchbox bronze PLA was set at 180 while the Metalink blue was set to 200.

(My Dreamer has upgraded nozzles which tend to make Hatchbox PLA print at lower temps than the original nozzles.  However, I just got this Metalink filament recently and used it to print all the sea tiles for a Settlers of Catan set quite nicely at 200C.)

For the second attempt I decided to turn on retraction and coast at end.  I was trying to avoid using a priming pillar because pillars really add to the length of a print.  I find that the priming pillar needs to be 10 or 12 mm square, minimum, to NOT break away from the print bed.  When your pyramid is 30mm square at the base, that priming pillar adds significantly to the overall print time.  So, retraction on to 2mm, coast at end of Simplify3D's default .2mm.  Result: a still very crappy looking frustum.

Third attempt: increased the retraction to 5mm and the coast at end to 2mm.  (Yeah, that's a big jump in the coast value.)  I also lowered the temp on my Metalink filament to 190, since it was still leaking little drops of blue all over the place.  The threading seems to have gotten even worse in this one.

Fourth try: all right, I'm turning on the ooze shield.  I use this feature a lot when I print dice, since it helps prevent cross-contamination of the filaments.  I'd been trying to avoid this since it adds to the print time; not quite as badly as the prime pillar, but noticeably.  In this case, the print time went from 36 minutes to almost exactly an hour.  Yikes. 

On the other hand, the ooze shield made that fourth frustum come out far nicer than any of the previous attempts.  I did leave my retraction and coast set the same as the third attempt, but the ooze shield clearly made the biggest difference.  I'll have to experiment further with tweaking the retraction, extra restart distance, and other related settings.  For now though, when someone has a critical need for a pyramidal frustum, I'll have to stick with the ooze shield.