Mystery pauses in extrusion.

[cssmythe3]

This is a very strange recurring problem I've had on my 3dp1000 that I've been using with Simplify version 3.1.0, especially on big prints. I'm using UltiMachine PLA.

The extrusion worsens, stops, and then restarts. A solution would be great, but at this point I'd be happy just to get a good idea what the source of the problem is.

Region 1 was filled first, then region 2, etc.

Region 1 was fine. When it got to region 2, I heard a periodic clicking sound and it seemed that the extruder did a short, fast retraction of the filament, then proceeded to extrude at the normal rate. This caused gaps. This happened on long, straight infill lines, resulting in about 20% of the line having no material.

When it got to region three, the frequency of the clicks (still with a regular period between clicks) increased dramatically, resulting in 80% of the infill missing.

Finally, in region 4, the material stopped extruding all together.

At first I thought I had witnessed a nozzle becoming clogged in real time – but I stopped the build, and could easily push material manually through the nozzle. I restarted the machine, tried building a different part, and the nozzle worked fine – so no clog.

Here you see something similar in a vertical wall. The blue lines are very solidly built, red areas have very poor extrusion, and the yellow areas have moderate extrusion.

Note in the red region the very regularly spaced dots.

I also printed the part with a brand new nozzle and it still happened, another indication it's not a clogged nozzle.

Could this be due to:

• a clogged nozzle? Unlikely for reasons listed above.
• debris inside the stepper motor or driving gear chamber? I haven't completely disassembled the drive assembly for a few months.
• simplify3d? I doubt it, because the drawing a single line of filament on the part is a single line of gcode, and if the extrusion is turning on off multiple times per line the problem is somewhere else in the system.
• bad stepper driver or motor?
• bad wiring?
• bad firmware in the 3d printer?
• lack of lubrication in the print head? It's been a few weeks since I've lubricated the nozzle.
• filament variation?
• print speed? I'm running at a fairly fast 3000 mm/min on the infill - the 3dp1000 is VERY over-engineering on the screws so the steppers can easily hit this, and the E3D head is rated for 8mm^3 / second and 3000mm/min with a layer thickness of .2mm and a line width of .36mm is only 3.6mm^3 / second, so no problem there.

I'm reprinting the exact same part with the same settings to see if this is random (implicating clogs/debris/bad wiring) or repeatable (implicating software/firmware).

I also have Reptier Host, so I may try a different slicer to see if that helps, but I'd really like to stick with Simplify3d in the long rung, I like the interface A LOT more.


Chuck in Brooklyn

[dorsai3d]

Region 1 was fine. When it got to region 2, I heard a periodic clicking sound and it seemed that the extruder did a short, fast retraction of the filament, then proceeded to extrude at the normal rate. This caused gaps. This happened on long, straight infill lines, resulting in about 20% of the line having no material.

When it got to region three, the frequency of the clicks (still with a regular period between clicks) increased dramatically, resulting in 80% of the infill missing.

Those clicks and "retracts" are the extruder skipping a step due to too much resistance. This could be caused by quite a few things, but is very unlikely to have anything to do with software or firmware (unless you have stepper current settings in firmware?).

You may want to check that nothing is overheating, and that your heatbreak is well cooled in case the plastic is melting too high up and causing intermittent jamming before melting and clearing.

[cssmythe3]

Region 1 was fine. When it got to region 2, I heard a periodic clicking sound and it seemed that the extruder did a short, fast retraction of the filament, then proceeded to extrude at the normal rate. This caused gaps. This happened on long, straight infill lines, resulting in about 20% of the line having no material.

When it got to region three, the frequency of the clicks (still with a regular period between clicks) increased dramatically, resulting in 80% of the infill missing.

Those clicks and "retracts" are the extruder skipping a step due to too much resistance. This could be caused by quite a few things, but is very unlikely to have anything to do with software or firmware (unless you have stepper current settings in firmware?).

You may want to check that nothing is overheating, and that your heatbreak is well cooled in case the plastic is melting too high up and causing intermittent jamming before melting and clearing.

The 8mm^3 / second might be suspect. I slow down my print speed and see if that helps. Thanks!