Electrifi filament being crushed in feeder

[JeremyK 2]

I am somewhat new to 3D printing and very new to the Ultimaker 3. I am trying to make a simple dual extrusion test part with PLA / Electrifi conductive filament. Both materials appeared to feed fine, but after sitting still while the PLA section was being printed, the Electrifi filament appears to have been crushed by the feed and was unable to be driven forward.

I pushed the release on the feed and fed some of the filament manually and it extruded fine, but the crushing of the filament still occurred. I've not been able to find this in the manual and don't want to start randomly turning screws: How do you reduce the tension of the drive in the feeder mechanism on the Ultimaker 3 extended? Also any tips for setting the tension on a softer material?

Thanks

[neotko 1,417]

Isn't that a 1.75mm filament?

http://www.instructables.com/id/175-Mm-Conductive-Filament-Feeder-redesigndevelopm/?ALLSTEPS

I tested that mod and can work, but you will need to print really slow and without reliability.

[abesanity 0]

It comes in 1.75mm and 2.85mm. Which size did you purchase?

[JeremyK 2]

I am using the 2.85mm diameter filament. The stress on the filament in the feed is just enough that it doesn't immediately crush it, but given 10 minutes of pressing on one spot, it will.

On the positive side, the filament does seem to hold up to it's promises, at least the little that I have been able to print. An analog ohm meter shows it dropping to 1-0 ohm over a 1" section as I wiggle the probes. I feel that if I can get it to feed right, I can get a constant connection.

[JeremyK 2]

Well, I turned down the feed tension by one tick mark. I believe I have found my issue.

The Electrifi filament is too soft to handle the repeated "retract filament" moves that the Ultimaker 3 loves to do. I think what was happening was that with each retract move, the same section of filament was being worn thinner and thinner. So I turned that feature off.

Second, buried in the multi3d FAQ, is an obscure little statement that while the print temperature is 160c for the filament, Ultimakers need upwards of 180c due to the heater design.

I reset the print to print at 200c, 20mm/s and turned off retract. Visually the print looks a lot better, with no pits or holes that I was seeing at the lower temperature. Electrically, I am beginning to seriously question the sanity of the guys over at Multi3D. There is not a single meter in the lab (a university robotics laboratory) that can measure the resistance of this stuff at less than 2 Mohm. But I want to give this stuff a fair and objective review, so I have coated segments on both test parts and a 6" section of raw filament with silver solder paste (Radioshack no. 2760037) just like they do in their FAQ. I will see tomorrow if their claims hold water.

If you guys are interested, I will post my findings.

-Jeremy

Edited February 18, 2017 by Guest

[neotko 1,417]

If you want a more reliable feeder you could change them to bondtech. Buy isn't easy since UM signs the firmwares, and to edit the estep information (required to change a feeder) it needs some know-how of using ssh, editing using vi, and stuff that's easy, but a pain in the arse.

[abesanity 0]

Id be interested in the results, they post really low resistivity on their website.

[JeremyK 2]

@ neotko,

I'd prefer to avoid changing the feed mechanism unless I absolutely have to as the printer is lab property and only a few weeks old. Thank you for the advice.

@abesanity,

The results were horrible. I copied the testing procedure they listed in their FAQ, both with two printed parts and a 6" segment of the raw filament. I coated the contact points with silver paste and none showed any measurable level of conductivity anywhere.

I have since contacted them and they sent me a procedure that they wanted me to run before they would process a refund (mainly testing segments from the opposite end of the roll), but I was instructed by my supervisor to abandon the filament for other options.

I have ordered and received a roll of Blackmagic3D's conductive filament, which boasts similar properties to the Electrifi. I haven't had a chance to print with it yet, but random probings with a multimeter showed consistent resistivity on the order of 200 ohm/inch (already an improvement over the Electrifi, so I am hopeful). They also claim it is stronger than both PLA and ABS, so it should definitely be an interesting material to work with.

Edited March 2, 2017 by Guest

[JeremyK 2]

The initial reason for this thread has been solved, but I wanted to post a follow up regarding BlackMagic3D's conductive filament.

I repeated the same print tests that I performed with electrifi's filament and found that the test piece had a resistivity of 80 ohms between the conductive plates. Width of the test segment was 0.25", the length of the test segment was 1", and the thickness was about 0.05". I calculate the volumetric (cm^3) resistivity to be approximately what is claimed (1 ohm/cm^3).

[abesanity 0]

Thanks for the updates Jeremy.

I wonder if the print temp was too high on the Ultimaker, Electrifi lists an increase in resistivity as the print temperature increases. They claim around 0.04ohm-cm at 150C and 0.045ohm-cm at 180C. I'm not sure how accurate the latter value is. Id be worried about oxidation at >150C, I wonder what other people think.

I'm going to give the Electrifi a shot on a lulzbot mini in the near future.

[Shayde 0]

Hey Jeremy,

did you get the Electrifi filament working now anywhere near the resistance they said it should have?

Thanks!