Out of ideas - print surface issue

[arhi]

this cube has nothing to do with tuggin issue .. but that white thingy, definetely ... and looking at your setup, does not look like tuggin is the issue but since effect is the same I'd say its something related for sure ..

this overextrusion means either your firmware is not calibrated ok or something is wrong with the extruder .. since you actually do have few other printers that do print nicely, why not first try to replace the whole extruder, if that solves the problem you know it's in the extruder .. then, return the old one (this that is not pushing out happy toughts) and replace only stepper motor, if that helps you know it's the motor, if not, replace the hotend etc .. and get to the bottom of it ..

this cube shows uneven extrusion, either filament or extruder is faulty .. I seen that with transparent PLA with a "dirty nozzle" .. I clean a nozzle, it prints "glass like" parts for few days and then I start getting bubbles and crap .. I cold pull the nozzle and find charred crap in no clue where it come from .. now I'm pushing filament trough 3 kinder egg shells on every one of my printers first eggshell holds the sponge, second the silika gel, then there's a ptfe tube and pre extruder there's another eggshell with more silikagel and another small sponge .. and now I don't have that problem .... but does not have to be that, can ba anything, as I said, start first by replacing whole extruder just to be sure there's the problem, and if it is then start piece by piece, motor, grabber, nozzle..

[bananaman]

Thanks guys, I do have another new j-head so I'll put that on and try it this weekend. Perhaps it has a machining defect.
I can easily push through the filament by hand.
I'm sitting next to a large vase printed in that green on another machine. It has that nice pearl luster and the layers are clear and transparent.
The extruder drive cog has fairly coarse teeth, I'll change to a milder one. I'll also cut back the tension spring and report back.

[wirlybird]

What brand etc. is that green?

[bananaman]

Blueprinted Translucent Green, I think.

[bananaman]

An update, haven't been printing with that machine. Just had a look, my PTFE guide into the J-head had a gap. Probably no issue. But I did find a very small sliver of tubing inside the nozzle, like a tiny finger nail clipping. All cleaned and purged, its printing a small vase right now. Using the same filament, using my usual settings and seems a lot better at this early stage although its a very humid day.

I'll test more, and report.

[bananaman]

Ended up bad looking, got worse as it narrowed. I'll try again when the air isn't so wet.

[bananaman]

Gave up on the JHead (original) replaced with an E3D V6 (original).
I don't know why there would be such a difference.

Same filament, same .stl, this pic JHead although 0.5mm nozzle.

E3D print 0.4mm nozzle, first print was a 20mm cube, looked fine, this is second print, still needs some tuning, much happier with it.

[bananaman]

Much, much better 0.5mm nozzle now.
Still a little tweaking to do.
In the end the only real change was the hotend.