PLA Expanding in the extruder head

I have been having feed issues with my Taz 5.

Problem 1

If my prints are smaller, say 15 hours or less it prints just fine. While printing larger prints, up over 20 hours I keep getting feed jams, I would say about 75 % of the time.

While browsing the forum I have read about heat creep in the filament.

I am printing PLA, I was printing at 210°, I need the higher temp for my first layer. I started lowering the temp after the first layer, I am down to 195° now.

It seems like I have gained a few hours but still having the issue. The filament checks good on diameter, .112" ( 2.84 MM ) all the way down the filament, past the hobbed bolt in into the print head, except for the last .250" or so, the material is swelled up to .120" ( 3.048MM ) It is swelled up large enough that it is difficult to pill the filament out of the extruder. I am debating taking the extruder apart and opening the through hole up .002 - .004 and see if that helps, but that’s a last resort.

So far I have had the issue using IC3D and Gizmo Dorks. According to Lulzbot tech these are crappy filaments, my problem is, this is all I can find. I buy from Amazon, everything in black is out of stock.

Problem 2

Filament size, Lulzbot reccomends 2.85MM Ø, everything I find says 3MM ± .01MM except for a select few that are 2.85MM, Gizmo Dorks being one of those. SO my question is, what is everybody else using and where do you get your filament?

Every 3mm filament is somewhere between 2.85 and 3mm. 3mm ±0.1mm is the normal declaration for this.

I guess thats not a cold pull what you are showing in the picture, so it’s not possible to say how much from your swell is normal due to the heat brake. Try to do a clean cold pull (even the shape of the nozzle should be visible), then it’s easy to compare with normal values.

You are getting what is called “heat creep”. It turns out to be a common complaint with PLA. (No one tells you this. You have to figure it out yourself.)

On the Taz6, they replaced the tiny blower that cools the heat sink with a 40mm fan and a duct. Cured the heat creep problem with PLA. The big fan is a bit overkill, in my opinion, but it makes all the fans identical and cuts down on inventory, I suppose. Here is a link to the TAZ6 duct:

I chose to CAD up a small duct that uses a 25mm fan. Completely cured the problem with jamming when printing PLA for me and seems to work for other folks too. Direct replacement of the tiny blower and doe not obstruct your view of the nozzle. Here is the link on Thingiverse:

I also put on a circular duct to cool the print from all directions, but I also have another head with two fans, like the Taz6, and that works as well and doesn’t block your view of the nozzle.

Bill D.

On the Taz6, they replaced the tiny blower that cools the heat sink with a 40mm fan and a duct. Cured the heat creep problem with PLA. The big fan is a bit overkill, in my opinion, but it makes all the fans identical and cuts down on inventory, I suppose. Here is a link to the TAZ6 duct:

Does the larger fan plug directly into the plug for the smaller fan?

The Taz6 (and later editions of everything) have a single large connector for everything. Makes it less confusing. Nothing to mix up.
You extract the pins that are for the fan, and replace them with the new ones from the new fan.

The board is still a RAMBO board, so the fans should be compatible. Have to check with the Lutzbot folks to be sure if they have stayed with the same five volts for that fan. (They are available in 5 volts.)

It is a HUGE fan, however. Works, but is way overkill, in my opinion.

I found this on their site;

It’s 24 volt, but looks to have the same connector as the small fan that is currently on the printer head, maybe I will give them a call.

I went ahead and printed up your smaller duct, and ordered the smaller fan. The plug for it appears to be different than the small squirrel cage type currently on the printer, did you need an adapter? Or am I just looking at it wrong? Can you post a picture of your connection?

The tiny blower is 5 volts. When I decided to build my heatsink duct, useing a 25mm fan, I bought a 25mm, 5 volt fan so it would simply swap for the stock 5 volt blower.

It isn’t clear what you what to do. If you want to do the 25mm fan and the duct I designed, then you will want to adapt the fan to the existing bower wiring. There are two (2) ways of doing this.

  1. Cut off the connector from the 25mm 5 volt fan, leaving several inches of wire on the fan. Cut the blower wires, but leave a couple on inches of wire on the blower. Slip a couple of pieces of heat shrink tubing on the new fan wires. Solder the new fan wires to the wire on the printer that supplied power to the old blower, being sure to connect red-to-red and black-to-black. Slip the heat shrink over the joints to insulate, and shrink it over the solder joints.

  2. Get a few spare male pins from digikey, or your favorite parts place. Crimp the new pins on the new fan wires. Extract the old pins from the original connector and replace with the new pins. Do this one wire at a time to keep the polarity correct.

Most folks opt for #1 as it just requires a soldering iron, solder, and heat shrink. It looks a touch messy when you are done, but it works fine.
I used opting #2 because I had the pins on hand, I had the correct crimper (which is expensive), I have extracted many pins before, and the result looks “factory”.

Bill D.

Thanks! You have been a great help, I printed your small duct and ordered the 25MM fan. I will snip and solder the connector. Again, thanks for your help!

I’m having this issue and thought I would post here rather than start a new thread. After some research and discussion with support I added a 5v 40mm fan to replace the tiny fan. Here’s the mount I used:

PLA and PETg are the two plastics I use and I’m continually having this same issue. I keep my room cool and I’m printing as low as I can while still allowing layers to bond. The fan is working great with way more airflow than I had before. I’m at a loss.

Any feedback is appreciated.

I upsized to the 40MM fan a few weeks ago, the 25 helped but didn’t solve my issue.

Even after the 45MM fan, I am still having issues.

I am in the process of trying out different filaments.