E3D V6 random clog and unclog

After various issues with my E3D v6 I got some replacement parts from E3D. Now it clogs and unclogs randomly, I really don't know what is happening here.

At some height the extruder stops extruding and the motor starts clipping, after 1-2 layers it starts again extruding fine.

You can see the result in the attached photo.

I'm printing PLA at 215°C, 1mm retraction at 30mm/s, with 30mm/s regular print speed.

What can I do? What is the issue here?

I've seen this problem before, some things I would check:

Cooling-> active cooling on your controller board on all the time

hot end (fan on all the time 100%), and if the motor is getting hot (check the current setting) put a heat sink on it or set a box fan near by blowing on the printer keeping it as cool as possible.

Repair your prints before you slice them. Netfabb works good:

[github.com]


I have made several hundred prints and haven't had a clogged extruder or skipping for several years

Edited 1 time(s). Last edit at 06/14/2017 08:29PM by bob632.

Hi bob632,

I have active cooling enabled. It goes from 35% to 60% fan speed.
I have the hotend fan on at 100% all the time (the one on the cooler block)
The print are fine, I check every single gcode that the slicer makes in order to avoid getting bad prints.

I tried disabling retraction, the problem seemed to go away but it clogged again.

It seems that the pla hardens just before the nozzle, even if the extruder temperature is set to 215°C or 225°C. When the extruder stopped extruding, I tried to pull a few centimeters by hand and push them down again, the filament came out without issue, then at some point it stopped working again.

I really don't know what this can be, this extruder is said to be one of the best out there but it's driving me crazy. (And it's making me waste a lot of filament too.)

How old is the filament? Does it behave the same with a different brand?

The filament is a couple months old, it worked perfectly before switching to v6. And yes, it does the same with a brand new filament from other brands.

Too hot is as bad as too cold. Try reducing your nozzle temperature to about 190-200.

What happens is that the heat seeps up the filament and softens it higher up in the hot-end, where it swells and jams. Retraction would make this worse.

You haven't wasted a lot of filament until this happens at the end of a 20-hour print job.

I'm using 215°C because at 195-205°C it underextrudes.
I used to successfully print at 195°C with my old direct-drive MK9 extruder, it's impossible with my E3D V6.

Edited 1 time(s). Last edit at 06/15/2017 05:29PM by harlandraka.

I don't think extrusion amount is temperature-dependent???

Try it at 205 and increase the "Flow multiplier" to compensate for the low flow rate.

BTW, are you sure your E3D thermistor is the same as what you had before? Maybe the temperature being shown isn't correct?

The extrusion amount is temperature-dependent. If the filament is not hot enaugh it doesn't melt properly and the extruder can't extrude it properly.

I already tried 205°C, sometimes it extrudes, sometimes it clogs. And below 205°C it underextrudes and clogs.

The thermistor is not the same I had before, the MK9 had its own chinese thermistor, while now I'm using the one that came with the V6 and it's properly configured on Marlin (I followed their wiki and did a PID autotune too).

I still cannot guarantee that the temperature is right as I have no way to test it "by hand".

Also check the wiring to your heater (especially near the heater cartridge) and your temperature graph for large fluctuations. Maybe there is a partial break in the heater wires?

Can you guide me through this step? How do I check?

Look at your temperature graph on your host program; e.g. Repetier Host, Octoprint (assuming you have one). If there are large changes in temperature (more than say +/- 5 degrees) whilst printing then you have a problem.

What can happen is that the wires to the heater flex and bend as the nozzle moves around the bed. After enough movements, the wire breaks. The most common place for a break is right at the heater cartridge, where heating makes the situation worse, and where bending tends to concentrate. Inspect closely to see if there's a broken wire, or whether the wires are frayed. Frayed bare wires just outside the heater cartridge may also short together, in which case you may see a glow there. However, the break could be anywhere along the wire... anywhere where a lot of bending of the wires happens. The wire may break inside the insulation, in which case it can be very difficult to detect. Also check the connector on the RAMPS/whatever board, which might be loose and/or moving, and any connections between the board and the heater.

To diagnose definitively can be difficult. You could add an LED + resistor at the hot-end so that you can see when current is flowing and when it isn't. Otherwise you could put a multimeter across the wires and try wiggling them in various places to see if you can replicate the fault.

Another symptom is that the nozzle jams at the same place in the print each time... until that point (or just before it), the nozzle position has kept the broken wire (or loose connector) touching. Then the nozzle moves a little further and the wire no longer touches, the heater goes off, filament cools and jams.

The same kind of thing can happen to the thermistor wires; most firmware will detect that the temperature has suddenly gone out of range and stop the printer.

To prevent this, you need to *rigidly* attach the wire bundle to the hot-end (cable ties or whatever) so that there is no relative movement. Similarly at the control board end. You then need to ensure the bending is evenly spread along the whole wire. Spiral wrap works for me, but other people use cable chains or other devices.

Ok so:

- The biggest temperature gap comes when active cooling goes on. I leave it off for the first layer, it goes on from the second layer: as soon as the fan begins spinning the hot end loses 2-3°C, but they are regained after 5-10 seconds. The print stops around layer 20 for one of my objects, so I suspect this has nothing to do with active cooling as long as the extruder temperature remains the same.
- Wires seem to be intact, there is no movement because they are already "locked" to the extruder cartridge, they can't move. Testing them with my multimeter seems to confirm this.

Here is one interesting thing: I tried to pull and push the filament again by hand. While pushing I could totally feel the filament passing on a "scratchy" surface at its end. I mean that I felt that the "head" of the filament (the part which you can push into the bowden tube and then into the extruder itself) was rubbing on an irregular surface once it entered the extruder. After pulling it a bit and pushing it again I could feel there is a point where the filament gets stuck, and I thought this could be the issue. Perhaps retracting takes the filament above this position and the filament gets stuck and can't go down anymore.

It could be that the extruder internal not being flat is not the issue, the extruder was almost entirely replaced by E3D after my first clog so I don't think this one is broken too.

I see lots of people use oil to make the filament go down smoother and avoid clogging, would you recommend trying this approach?

If your extruder motor isn't overheating and skipping steps, and the temperature is fine then that hot end should never clog, provided the top end of it isn't getting hot and allowing the filament to swell.

What slicer are you using?

The reason I suggested you repair you prints is it happens for a couple of layers then starts to work again, it looks like a slicer problem.

Info on why prints need to be manifold for the slicer:

[3dprintingninja.blogspot.com]

Quote:

Self-Intersecting faces will cause missing plastic around the intersection or just be skipped. Once a layer is skipped the next layer is unable to print on top of the previous because it was skipped. Everything printed afterwards is almost certain to fail. Sometimes a layer corrects the missing layer, but still it causes a significant error.


Craftware has a hard time with non manifold files

Edited 1 time(s). Last edit at 06/16/2017 10:37AM by bob632.

But as I said I check every gcode produced by the slicer to be sure that the object is correctly extruded. And as I said, even if I release the extruder clamp and push the filament manually, I feel I can't push it and the extruder doesn't extrude it, so the filament is stuck inside the extruder somewhere and won't come out. after a couple layers it unlocks and starts extruding again, but it's not a motor issue, as if I release the clamp and push by hand nothing comes out from the nozzle.

I'm using Slic3r since more than a year, I never had issues with it when I had the direct extruder. After changing to V6 the filament clogs too frequently. I stopped using S3D because it has a horrible support for mesh fixing, it isn't able to do it properly while Slic3r and Cura do it pretty good. Personally I think that paid software cannot have such flaws, S3D is certainly not cheap and should be able to deal with mesh repairs as free slicers do. I stopped using Cura because I don't have glass as print bed and I needed to customize settings for the first layer in order to optimize adhesion (speed, nozzle temp, bed temp, active cooling and so on). Slic3r lets me do that, Cura doesn't. I tried Craftware a couple times, I can't get a decent configuration, I got underextrusion everytime, no matter which parameters I changed.

So yes, I'm using Slic3r and everything was just fine until I switched to the V6.

And as I said, I've seen this problem before.

you aren't the first person to have this happen, read through these threads they're full of people with clogged extruders and what not.

I don't have this problem and haven't for years.

Good luck.

Correct assembly of the hot-end is important, otherwise a gap is left between the end of the heat break and the nozzle. Filament can expand into that gap and jam.

Screw the nozzle into the heater all the way, then back out 1/2 turn.
Screw the heatbreak all the way into the heatsink and then the heater finger-tight... too much force will break the heat break.
Use a spanner to tighten the nozzle into the heater block.
This all needs to be done while the heater and nozzle are hot.

Hey,

U have got exactly same problem as mine...
Do u have a solution? Already?
I have tried almost everything.

I'm not using the printer right now because of the problem

Thanks for your time!

Hi gertonwullink,

I followed this tutorial: http://www.dragonflydiy.com/2014/06/nozzle-seasoning.html

Basically, you need to add some oil to the filament and push it through the extruder.

I actually have put a little bit of oil on my dust remover so that the filament is always a bit oiled and I'm not experiencing a clog since July.

Hope it helps!

I just got a new E3D hot end.
I had this problem and initially solved it by raising the temperature 30 degrees. The next time I had the problem I needed to replace the nozzle. The NEXT time I had the problem I solved it by reducing my print speed.
These solutions were cumulative and the last solution was filament related. The filament was a little softer than the PLA+ that I was using before.
So...
The lesson is that this will keep occurring and you may have to tune to your filament if you change brands.
There may not be one solution for all conditions.
My esun PLA+ wants hot and can go fast (80mm/s). My BAMtack! Filament can't print as fast. My E3Dv6 seems to have a sensitive heater and is very sensitive to filament changes. Way more sensitive than my vanilla J-Head was. The thermistor reads higher than actual temperature too, which doesn't help. But it is an all metal end so the temperature is not important as long as the plastic flows! Since I stopped tweaking when I got things to work,!there may be more than one working combination too!

Keep plugging away until you get reliable prints and keep notes on your settings for each filament setup.

DLC

Edited 1 time(s). Last edit at 08/26/2017 10:51PM by dlc60.