Huge blobs and gaps with Taz 5 dual extruder

I’ve recently become responsible for a Taz 5 dual extruder. I do not know much about its history or previous problems so am just taking things at face value for the moment. The filament being use is Chromastrand Innova 1800.

The dual extrusion feature is really gnarly… The in the images below, the white (T0) does not want to adhere to the red (T1) on beginning layers. The red support prints cleanly and smooth, but the white is nothing but enormous blobs and gaps in the surface. The white has huge drips dragging all over the place.

The hobbed bolt is clean and fine.
The nozzle is not clogged.
The nozzle is clean/wiped itself
The filament is extruding fine and there is no shearing/flaking.
There is gluestick on the bed and I set it to do 5 skirts so it gets a nice clean extrusion from the get go.
I have tried both an ooze shield and a wipe/prime tower. Doesn’t matter which I use, the result is the same.

When printing in single color, there are no issues. The surfaces are smooth with minimal blobbing.

Any tips on where to go from here?

The gap between the two filament colors could be a calibration issue with the nozzle spacing.

The white looks as though its being starved of filament. Check the following:

  • Make sure the spool isn’t binding
  • Make sure you’ve got the right filament diameter set in slicer and check filament diameter being used.
  • Tighten the appropriate idler to ensure hobbed gear is engaged to push the filament through the hotend

Can you do a print with just the white filament?

Yes - prints with just the white (T0) come out smooth and near perfect. It’s only when trying to do a dual extrusion are things coming out weird.

When doing a pretty simple and flat dual extrusion, it comes out fine as well. It’s only when trying to print with the 2nd nozzle (T1/red) as supports only that this happens.

I will post pictures here in a bit after checking the spool, diameters, and idler.

Sorry for the delay.

There is no spool binding, the idler tension is fine (I’ve changed filament multiple times and am always diligent to check the hobbed bolt and idler tension), the filament diameter is set correctly (2.85 and I checked it with a micrometer multiple times).

I have also redone all of the e-Steps (those were way out of whack).

There is still some sort of major issue going on when changing between colors and doing supports. See attached image of totodile. T0 is red, T1 is white (switched it from last time). The surface is pretty smooth, could be better, with some white dragging here and there but nothing all that terrible. However, as you can see, it had major extrusion trouble when trying to switch from T1 back to T0. This went on for some 20, 25 layers.

I used an ooze shield.

Later I am going to test to see if two colors without supports fairs any better.

Today I finally caught the weird sound it was making when it stopped extruding… stepper motor troubles?? Would this have anything to do with the trouble I am seeing? Seems like it to me. It just stops extruding. It is most pronounced in T1 but is occuring in T0 too.

Video of sound and pictures of problems:

Well I have spent the last two days looking/testing the local libraries Taz 5 printer where they are using Innova-1800 and attempting dual extrusions using Cura. I know what the problems they are having just like this are and it is not the printer.

Check you T1 retract speed? That could be the sound…

Can you print with just T1?

Try a different slicer?