Filament extruding slowly after a while

Discussions about mechanics
Post Reply
dennisje182
Posts: 8
Joined: Wed Jul 10, 2013 2:18 pm

Filament extruding slowly after a while

Post by dennisje182 »

Hello everyone,

First, I'm not sure if it is in the right section, but i couldn't do a search since it isn't possible to go to the next search paste (bug in forum?).

But now my problem;

When i enter my filament and flush the extruder, it goes through without any problem and a nice constant flow comes out. But after a littler while (sometimes 50 mm, sometimes 200) the flow becomes much thinner and slower and it doesn't extrude well, and it almost comes to a complete stop. I also tried to start the print immediatly after flushing, but then it almost occurs immediatly aswell (during the drop before each print).

In the beginning I was able to print 3 parts, but then it started to do this.

After the jam, when I retract the filament, cut off the half melted part of the filament and enter the filament again, it flows like normal again until it becomes thinner, slows down and jams.

Anybody an idea of how to fix this?

kerog
Posts: 117
Joined: Mon Jun 09, 2014 1:54 am

Post by kerog »

Could be a lot of things. There was an extensive discussion of similar issues on the forum last year, that didn't really conclude satisfactorily from my perspective. Some people were drilling out parts of the hot end, inserting teflon tubes, and reporting better flow reliability.

Some possibilities:

(1) Extruder tensioning needs to be adjusted. Do you have springs in your extruder, or the wavy washer stack? I had better experience after replacing the washer stack with the springs.

(2) Nozzle contamination. You can rule this out by replacing your nozzle with a fresh one. Have you been switching between PLA and ABS? If you do this, I recommend getting some cleaning filament. This filament has a wide melt temperature, so you can run it at either PLA or ABS temperatures, flushing the system when you switch.

(3) Heat Creep. On some printers the isolation isn't so great, so the heat creeps up into the cold end, causing the filament to partially melt and stick. As I understand it, PLA is more susceptible to this phenomenon than ABS. What are you printing with? On the Felix, there is a fan blowing directly onto the hot end, which should help prevent this.

dennisje182
Posts: 8
Joined: Wed Jul 10, 2013 2:18 pm

Post by dennisje182 »

Thnx for the reply, here are my findings:

(1) doubt it is the tensioning, when the extruder is heated up and i take it out i get the same jam when i push the filament through by hand. Sometimes it flows through nice after i pull the filament out, wait a bit and push it back in, until it jams again pretty quickly.

(2) I just renewed my hot end tip, barrel and peek isolation. So its weird it has the same problems before i changed them and after. I only print PLA

(3) hard to check this.....i do have fan turned on which is aimed on the runner...

So that leaves the filament...? Which is from Felix and have been printing many meters without problems. I'll try a different spool later....but i dont know, im running out of ideas

User avatar
DDME-Marc
Posts: 71
Joined: Sun Nov 24, 2013 11:04 pm
Location: New Zealand

Post by DDME-Marc »

Interesting that changing components did not remove the problem. It does make you wonder if your temperature is actually stable and or not recovering quickly enough from fluctuating load (which in your case is the initial flow at start up).

I would suggest using the Repetier-Host to initially view the temperature curve. How quick do you achieve target temperature (from room temperature)? Once stable how many degrees do you drop when engaging a flow command?

Have you checked the Host extruder temperature readings against an independent thermometer?

Also just out of curiosity what firmware release are you on?

Cheers,

Marc
Felix 3.0 Dual Head * E3D Titan V6 * Repetier-Host V2.1.3 * Repetier-Firmware 0.92.9 (01/08/17 - Modified) * KISSlicer Pro - 1.6.3 * Arduino 1.8.5 *

Post Reply