I cleaned up my Flashforge Creator Dual tonight, and loaded some transparent ABS prepping for a print. The filament extruded fine, then started to wiggle, then became fine again. Hot end is 0.4 mm and was heated to 230C. What sort of steps should I take to troubleshoot the issue? Has anyone seen this before?
It might be similar to this issue (where teflon tube wasn't installed what caused softening filament inside heatsink)
Please check if your extruder is equipped with proper pipe inside (inner pipe diameter).
But the most probable cause is that a pipe had slide out so filament has enough room to get soft and to form such shape going out. Please take a look also here.
fig. B: 6. slided out teflon tube 7. empty space (heat)
fig. C: 8. bent filament
fig. D: 9. teflon tube 10. no extrusion
How it happens?
Teflon tube is usually well positioned so everything is fine in most cases. Sometimes because of poor filament (not-constant diameter) or because of bends on filament, teflon tube is slided out os its place while retraction. It goes on and on, up and up (fig.B)
Once tube is extended that much so filament starts to bend in empty (heat) space (fig.C) It increases the effect of sliding out teflon tube just because of bend (it works as a hook). But it can still work. Teflon tube can even be pressed back inside the nest.
Now because the empty space is heat then filament starts to melt (for example when there is no extrusion for a second) it becomes soft. When filament is soft enough it doesn't extrude as the force to press it throught the nozzle is too high for such soft material so filement definitely stops extruding itself. (fig.D) This situation cannot be fixed automatically. There is a need of user intervention.
Now you know why some extruders has a rim (or collar) on the top of heat barier tube. It secures a teflon tube from sliding out.
If the filament displayed in the photo is the result of unimpeded extrusion from your nozzle, you don't have or have not described a problem. Filament extruded from a hot nozzle will react to many things. If a slight air temperature change is created on one side of the extruding filament, it will cool faster than the other side and curve in the direction of the cooler temperatures.
If there is a bit of old filament on the tip of the nozzle, it can cause the filament to hook back on itself, creating an interesting squiggle of filament before the weight is sufficient to cause it to drop.
A typical 3d printer problem is related to the results of a print or an obvious mechanical failure. Wiggly extruded filament is not a symptom of a looming failure, unless you have other indicators.