Problems with hotend

[marktoml]

We have been struggling with a v3 for about a month now trying to get it working.
While we have a lot of FDM experience (and several other printers) this is our first delta style.
We started in 2013 and have worked our way through a number of prusa style and even a DLP we built ourselves.
Other than the fact that this is a delta we are not entirely new to this

Other than a too-short strip of bowden (we extended it 2 feet and they apparently had a bit of an issue figuring out how much to send us) everything was in the kit and it was not a big deal to assemble.

Unfortunately printing has been another issue. The extruder would not keep up with the hotend (all of this is using standard PLA by the way) and would begin skipping with extrusions of any length at or above about 100mm. Went back and forth with support a fair amount and never could isolate the exact problem. They ended up sending us an assembled effector (awesome!) however... it behaves the same way. I have toggled between the provided EZRStruder and a GregsWade to no avail. The EZR will soon after starting a print begin skipping and fail after the first layer (that usually comes out OK). The GregsWade likewise will just start wadding the filament up at the tube. Clearly too much back pressure. Mind you this is an entire effector that they assembled and sent us, behaving exactly the same as the one we built.

If we test the hotend loose with it heated up and using a short piece of bowden tube to manually feed in some filament it is very difficult to get any to extrude. Our other units (sadly all using E3D hotends) are very easy to manually push filament though by hand, but this one (and the original we built) are not. This is much harder to manually push filament through it.

At this point I am sure the back pressure is what causes the problems, but the best I could get was with a 2.0 mm (yes, you read that right) nozzle and even then eventually the extruder will fail to push it through.

Any ideas on what to try? I have plenty of other bowden tube, but changing that did not seem to affect this. I figured the GW would handle any minor extra extrusion pressure easy enough, but ... nope.

The back pressure is enough that I am convinced this is what killed the extruder stepper early on (we had a set of extras, but swapping that for a new one did not solve it -- the original is well and truly dead though).

[joe]

As a test have you cranked up the hotend temp to say 250? The pla should run like water at that and then work the temp backward 5 degrees at a time. Perhaps the thermistor is way off or have you measured it?

[marktoml]

Yes indeed. When we run it at 250 it does flow, but not for long.
By the time it gets to layer 2 or three at best it is only intermittently extruding.

I did measure the heater block at 210c and it is pretty close to what the thermistor is quoting.
I was pretty sure we could solve this and when they shot us a whole new effector I figured the problems were sorted, but I am fresh out of ideas.

I assume at some point the bowden tube is 'too long' for the stepper to push it through effectively, but I can't imagine that is really a contributing factor.
Seems like the hotend itself is the problematic bit to me, but two of them?

We do have an E3D here I had pondered with using since the others we have use those as well, but it is not a straightforward drop in and we would need to fab some bits first. I figured I would rather get it sorted in a stock configuration first.

[marktoml]

With no hotend attached it will happily feed through just the bowden tube all day long

[joe]

OK, So how do you go about restarting the print after it starts intermittently printing. Is it clogged and you have to clean out the nozzle or does it work right away when you start a new print. Does the temp vary much. Try turning off the bed heat ( i know you won't get good adhesion but some glue stick should work for one print) and see what happens.

[marktoml]

All we did was pull out the filament and make sure the hotend was clear then re-feed it.
It will print OK initially, but quickly fail. Even if we don't retract the filament and just do some test extrudes it will generally flow OK initially.
Bear in mind that just with the effector in midair, well off the bed, telling it to extrude 100mm will fail a little over half-way through.

It acts a lot like it is clogging. That is one reason we bumped up on the original one all the way to 2mm nozzles, but that didn't help either. It did manage to print a bit longer, but still failed fairly quickly.

I did try seasoning since it was PLA, but no real change in behavior there either.

We have made sure the bowden tube was fully inserted, many, many times It will not go in any further by hook or by crook.

I have tried slowing down print speeds as well by 50%, did not seem to affect it.

edit: The temperatures seem to be really steady. They do not move up or down to any extent. Cold bed or hot, the extruder misbehaves.

[joe]

have you tried hooking up the extruder to the second extruder driver? that would eliminate a bad driver.

[marktoml]

Good idea and I will give it a whirl, but I am not certain that is going to change anything.
The fact that I can not easily feed filament throught he hotend by hand is what bothers me.

I will try that and get back to you though.

[Laughingmonkeylabs]

I was having the exact same issue. Manually pushing filament through the hot end at high temps aka 250 and it was near impossible to push. I ended up replacing the entire hot end and it solved the issue. Best I could figure was the heat break was damaged from either the bluprint material i used before the issue started or from running it at such a high temp.

[Dale Eason]

I had a similar problem with my conversion of V2 to HE280 hot end. Started working to begin with but soon the extruder started to skip and the filament stopped moving.

Eventually after taking the hot end apart including taking the heat break off I found the heat break upper part completely blocked with melted filament. This was caused by my not inserting the PTFE tube far enough into the hot end. I also had the retract setup on my slicer to be 6mm which was then sucking hot melted filament into the heat break where it cooled and then blocked the path.

The fix was to get the PTFE all the way to the bottom of the heat break top end and to shorten the retract to 2mm.

So what I think may have happened to you is that although you thought you had the PTFE Bowden tube seated all they way in you probably do not. You may also have the retract too large. To see if you have it all the way in, take the PTFE back out but notice how much was inside the hot end. That amount should go almost all the was to the heat block if you lay it beside the hot end.

I found it hard to seat the PTFE all the way into the hot end unless I sanded a little around the edge of the end of the tube to chamber it a little bit. Then it would slide in easily.

[gsnover]

My HE280 clogged repeatedly out of the box. The issue was the PTFE tubing not fully seated. I could never get the PTFE fully seated after disassembly and chamfering the PTFE tube, it was never a reliable fix. I'm just going to switch to an e3d v6. Having the PTFE tubing go all the way down to the heat break is asking for trouble in my opinion. This how e3d lite's are designed, while the V6 has the heat break going half way through the heatsink. It just makes more sense to not have that dubious seal of the PTFE tubing against the heat break in such a critical area. my 2 cents.

[marktoml]

Well, I removed the heat break and made sure the tube was flush in the bottom and reassembled it that way (with the tube already in-place). I made sure it did not pull back out while assembling so ... I cam pretty darn certain that the bowden tube is all the way in. It will not move in any further regardless of how hard I push on it ...


Even using a small (5 inch) section of tube and then after assembly trying to push filament through by hand is the same.. .very difficult to get anything to extrude. Disassembly after that does not have any filament clogged, stuck, 'pucked' or anything odd (there is still some in the nozzle).

Not new to printing, but am new to bowden only... This has me pulling my hair out. The new E3Ds use a small bowden section for them as well even on non-deltas with the Greg's Wade extruders and I have never had an issue with those either.

I really expected the replacement hotend to sort this. If it IS a bowden tube issue I am just unable to mechanically push it in further by hand. Do I need tools?

[marktoml]

Frankly I feel like I must be missing something obvious. Clearly others have this working
Will shifting the extruder to the second extruder output on the RAMPS (as suggested) work without tweaking the firmware?

[marktoml]

My HE280 clogged repeatedly out of the box. The issue was the PTFE tubing not fully seated. I could never get the PTFE fully seated after disassembly and chamfering the PTFE tube, it was never a reliable fix. I'm just going to switch to an e3d v6. Having the PTFE tubing go all the way down to the heat break is asking for trouble in my opinion. This how e3d lite's are designed, while the V6 has the heat break going half way through the heatsink. It just makes more sense to not have that dubious seal of the PTFE tubing against the heat break in such a critical area. my 2 cents.

If you come up with a handy way of mounting the E3D please share. I have one that I purchased because I had given up on the HE as well and ... then realized that it was not a drop in or even a jury-rig drop in

I figure I would have to CAD up a new mount.

[Xenocrates]

My HE280 clogged repeatedly out of the box. The issue was the PTFE tubing not fully seated. I could never get the PTFE fully seated after disassembly and chamfering the PTFE tube, it was never a reliable fix. I'm just going to switch to an e3d v6. Having the PTFE tubing go all the way down to the heat break is asking for trouble in my opinion. This how e3d lite's are designed, while the V6 has the heat break going half way through the heatsink. It just makes more sense to not have that dubious seal of the PTFE tubing against the heat break in such a critical area. my 2 cents.

If you come up with a handy way of mounting the E3D please share. I have one that I purchased because I had given up on the HE as well and ... then realized that it was not a drop in or even a jury-rig drop in

I figure I would have to CAD up a new mount.

I would use either the 713maker mount (Once they start sales up again, as they are taking a holiday break to do maintenance and attend a maker faire,), or check out Tricklaser's options, which has a mount for the board and a groove mount adapter. You're looking at 32-35$ in parts to do so. I personally would wait for 713 to come back since I like their parts and the people behind them a lot and while you pay some more, you get a more attractive and complete solution than Trick laser offers, but if you're impatient, that's less acceptable.

Trick laser
Probe board adapter
Groove mount (E3D mount effectively)

713Maker
Config page
Basic kit with accelormetor lock ring, 34MM spacers, and whatever color you like.

[Dale Eason]

I tired your experiment where you only have a few inch PTFE sticking out of the hot end. I used 1.75mm ABS and a nozzle temp of 230. I found it easy to push and extrude. It took a little force but not extreme. Maybe equivalent of 5 to 10 lbs. However I can not figure out why yours is hard. Has to come down to either not heating up, or is clogged or blocked somehow.

Have you tried removing the tip and then feed filament. Did It feed ok? You may have to heat it up to remove the tip. But since you got the heat break undone you probably already know about that stuff.


Dale

[marktoml]

With the nozzle off it feeds easier. Not sure if I can say it feeds as easy as I would expect, but easier. I tried running 1000 mm through with the nozzle off on the original one and that worked fine. It only failed entirely when the nozzle was on. The best results were with a 2.0 mm nozzle (yea, huge) but it still would fail eventually.

Since both effectors are behaving the same way I am sure that it is not an assembly issue for that part. Their support is convinced that it is the bowden tube improperly seated. I have no idea what else to try to insure that it is seated correctly. I am convinced it is something else myself, but it is their hotend

[marktoml]

713Maker
Config page
Basic kit with accelormetor lock ring, 34MM spacers, and whatever color you like.

Thanks! I have sent them a request for that one.

[marktoml]

I think the solution is in-house. This plus the E3D should do it.

I will update this thread when we do it (probably tomorrow)
We had to go with TrickLaser since the other folks never would respond to requests.

[marktoml]

Did the swap on the spare effector we had. Pictures attached. Loots great.

It is a nice upgrade. Redid the autoleveling config as well.

BUT IT DID NOT HELP

I am not sure what is wrong, but I know what it is NOT:

1) It is NOT the extruder (theirs or the GregsWade)
2) It is NOT the filament
3) It is NOT the bowden tube.
4) It is NOT the extruder stepper itself (we already replaced that due to the original they sent with the kit dying).
5) It is not the hotend (theirs or the E3D)

WTF

I am out of ideas.

On my other printers I would be suspecting the pololu stepper driver or the RAMPS. No clue on this setup.

Help?

[marktoml]

Just as an aside, the kit for the E3D hotend was an easy one to put together and assemble. Everything worked well. We had to order the following:

Probe Board Adapter Item# PB-ADPT
Hot End Groove Mount for Rostock MAX Item# RM-JHGMNT
Carbon Fiber Tube Stand-Offs 36 MM Item# CFSTAND36

That was all that was needed to get it to adapt since we reused the parts fan mount and fans. They sell a CNC version of that as well for a bit more if you want it.

We landed the heater core and thermistor wires onto the electronics/accelerometer board the same way the stock stuff lands. Editing the thermistor type in the firmware to match what E3D supplies and good to go

[marktoml]

So short of any other ideas I am going to slap together an arduino/ramps combo and tie it to just the extruder stepper and see if it works correctly when manually extruding. I don't have a spare RAMBO to swap in.

[marktoml]

In a last ditch effort to narrow down what is wrong we decided to take the bowden tube from the Rostock and feed it into the E3D hotend for one of our Cartesian printers. Hold it in place heat it up and try to have the Rostock extrude. We KNOW the non-delta extruder works fine so ... if that does not extrude correctly we can be sure that the problem is in the electronics or the drive motor(s). If it behaves the same as extruder in the effector we can be sure that somehow we have still got a bjorked effector.

Testing ensued...

With the other (non-rostock) machines hotend heated to 210c we took a short piece of bowden and was able to feed filament through fairly easily.

We then took the bowden tube from the Rostock and feed it into the E3D and held it in place. When trying to extrude from the Rostock it (the ezstruder) was skipping like crazy and not extruding much at all and then finally I was unable to hold it in place and it pushed the bowden tube back out.

I have discussed this with a friend who uses a bowden fed Sigma printer and he is of the opinion that the extruder stepper is too small/weak or the driver for it is not pushing it enough.

Any ideas ???

[geneb]

The motor is fine. I'd suspect a production flaw in the PFTE tubing at this point. Pull off a few feet of filament and remove the bowden tube from the 'max. Hand feed the filament scrap through the bowden to see how much resistance you experience...

g.

[marktoml]

We completely replaced the bowden (twice actually)

I got it working. I googled this up and lo-and-behold a link to this forum (completely different printer sections, but...)
turns out the fix was to increase the motor current. The default is 135 (in repetier) out of 255 max. When I took it to 175 it was mostly skip free and i set to 195 for zero skippage!

Now I am off to get bed adhesion working None of my tricks from the other printers are working here. I can deal with that.

Thanks!