RE: Rebuilt extruder and now having load and extrusion issues
Yes, you can dial a different temp under the tune menu during a print.
RE: Rebuilt extruder and now having load and extrusion issues
Thanks @vintagepc. Worked perfectly to dial in my Live Z*.
So, it "worked" in that I successfully printed what looks like a good 75x75mm square to dial in my Live Z again.
After making the MMU happy (ugly tip from earlier jammed things up) the load to nozzle function worked flawlessly. During the bed leveling, however, it was dribbling quote a bit (as I would expect at 230 for PLA) and left nits all over the plate. Printing my Live Z test went fine otherwise.
I was going to try a 2 color Benchy at this temp to see how that did, but when I unloaded the filament and checked the tip I found this:
Based on that tip and the dribbling I suspect that the nozzle is at the reported temp and the heat break (for whatever reason) is cooler than it should be. Thus when filament is pushed all the way to the nozzle at 230 it simply wants to melt and run out while above some point it is staying cool enough to not melt as readily.
* Yes I recognize that this Live Z result is probably meaningless due to the high heat.
RE: Rebuilt extruder and now having load and extrusion issues
Found my thermocouple and even a regular 9V battery since the multimeter apparently was not happy with the LiPo battery I gave it (said my hand was 119 degrees Fahrenheit...). After sorting that out I got the following temps while the extruder was set to 215:
- Tip of nozzle: 160 (hard to keep the TC in place so it is probably a few degrees warmer)
- Block above the TR: 188
- Block above the core: 195
I can't speak to the accuracy of my thermocouple, but I doubt it is 20 degrees off. Comparing it to a cheap thermometer in Fahrenheit for ambient temps it is reading 2 degrees low, but I have no idea which is more accurate.
Unfortunately I have no pre-rebuild numbers to compare too so I don't know if there is a change. I assume not though since the core and thermoresister seem to be in sync.
Back to the first post, 2 differences are that the block is E3D's copper block rather than the aluminum version and I added the sock. I've read that the block can take longer to warm up, but I'm having these issues even if it has been up to temp for 10+ minutes. Other than helping keep your nozzle/block clean, my understanding was that the sock kept your block temp more stable. Anything I'm missing with either of these "mods" that could be the root of my issue?
RE: Rebuilt extruder and now having load and extrusion issues
Thermocouples used with an uncompensated meter - or the wrong meter - can be off hundreds of degrees. It's called cold junction compensation. Without it, the measurement is not trust worthy, and basically useless.
Every metal to metal contact is a thermocouple. If the metals used to contact the thermocouple wires to the meter are the wrong ones, those contacts can easily swamp the thermocouple you want to measure. Add the cold junction compensation - most meters don't even know what that is unless they are calibrated and sold with thermocouples.
If you have a Fluke meter, a Fluke thermocouple built specifically for that meter, you're probably okay. Otherwise, I would not trust the temp reading.
And a third problem is that a thermocouple simply touching a metal surface isn't enough. The thermocouple wires draw heat away from the junction making the reading lower than it actually is. A thermocouple must be encased in a thermal compound for about 1/8 inch to get an accurate surface temperature reading - the idea that the junction and part of the wore is all at temp..
RE: Rebuilt extruder and now having load and extrusion issues
Thermal response times between copper and aluminum heater block are going to be minimal; and the sock helps in either case. I wouldn't go down that rabbit hole. When things are working, a PID call is in order - but the block material isn't the problem.
When you installed the thermistor, how tight did you get it? SNUG is the recommendation, not tight enough to deform it, or break the glass envelop inside the metal case. I doubt you did that, because if you had you'd probably be seeing nozzle temp drop to zero as it heats up. The other question is the thermistor itself: is it the normal E3D variety shipped with Prusa hot ends? Or did you upgrade to the Platinum thermistor (PT100)?
RE: Rebuilt extruder and now having load and extrusion issues
As for a cool heat break? That's probably another rabbit hole. As long as the heat break is butted solid against the nozzle it's not going to be too cold (I assume you used the V6 assembly instructions and everything is tightened according to them). Even if the nozzle is torqued against the heater block, and the heat break is loose, the printer will still print fairly well, but the hot end will leak out the top threads.
RE: Rebuilt extruder and now having load and extrusion issues
Now that was a proper Tim response 🤣
As far as the thermoreaistor, it's still the original that came with the printer (heater core too). I tightened it in enough that I couldn't pull or push it any more.
The core is similarly tightened, but I did have a hell of a time removing it from the old block. I literally had to rip part of the block away to get it out!
I've seen references to "PID" before. What is that?
RE: Rebuilt extruder and now having load and extrusion issues
PID (the name escapes me) is a process where the controller heats (as in applies power to) the nozzle and watches what happens. It adjusts the power applied ratio to compensate for fast or slow heat response. It allows the controller to heat at well controlled rates without overshooting or undershooting the target temperature.
Sorry for the Tim response... but just trying to help best I can.
RE: Rebuilt extruder and now having load and extrusion issues
Stands for "Proportional, integral, derivative". AKA the P/I/D values used to control the cycle, as opposed to lazy-man's "Bang-bang" method, wherein you just "bang" the power on and off at fixed "wings" on either side of the target temp to keep the "average" at the target.
RE: Rebuilt extruder and now having load and extrusion issues
To add to that, not only is a PID control monitoring the temp, it is trying to be smart about:
a) how quickly it's getting there
b) How long the system takes to respond to power input
c)how far it still needs to go
RE: Rebuilt extruder and now having load and extrusion issues
Maybe making some progress! I found and ran the PID calibration (left it at it's default temp of 210). Afterwards I measured the temp (210) at the thermoresistor and got 190 (was 188 earlier). When I bumped the temp to 215 it still read 190, though. So I'm less sure about my multimeter being of any value in this arena.
The important part, however, is at 215 I was able to feed filament through with Move Axis and it extruded. Further, Load to Nozzle worked at 215 as well. The tip wasn't ideal after I unloaded it, but that has always happened from time to time and importantly there was no tail.
So I'll run another Live Z test in the morning and give Benchy a try.
RE: Rebuilt extruder and now having load and extrusion issues
Posted by: tim.m30PID (the name escapes me) is a process where the controller heats (as in applies power to) the nozzle and watches what happens. It adjusts the power applied ratio to compensate for fast or slow heat response. It allows the controller to heat at well controlled rates without overshooting or undershooting the target temperature.To add to that, not only is a PID control monitoring the temp, it is trying to be smart about:
a) how quickly it's getting there
b) How long the system takes to respond to power input
c)how far it still needs to go
I need to learn French : at least I could blame the language when I say something and no one understands.
Turns out wiki has a good description: https://en.wikipedia.org/wiki/PID_controller
RE: Rebuilt extruder and now having load and extrusion issues
Posted by: tim.m30PID (the name escapes me) is a process where the controller heats (as in applies power to) the nozzle and watches what happens. It adjusts the power applied ratio to compensate for fast or slow heat response. It allows the controller to heat at well controlled rates without overshooting or undershooting the target temperature.To add to that, not only is a PID control monitoring the temp, it is trying to be smart about:
a) how quickly it's getting there
b) How long the system takes to respond to power input
c)how far it still needs to go
I need to learn French : at least I could blame the language when I say something and no one understands.
Turns out wiki has a good description: https://en.wikipedia.org/wiki/PID_controller
Ceci n'est pas une pipe? XD
RE: Rebuilt extruder and now having load and extrusion issues
No dice 😫
Load to nozzle worked perfect and filament extruded as expected, but other than a blob at the start of the purge line there was nothing and the print itself did the spray can effect. On stopping the print the filament won't retract and appears to be stuck. This is getting old...
RE: Rebuilt extruder and now having load and extrusion issues
Took it all apart and pulled the sock and both found what I expected and did not find what I expected.
So there is definitely no leakage going on:
The filament, however, is actually stuck in the heat break rather than having a bulb trapped by the PTFE. Shortly after that last pic I was able to get a good grip on the PTFE and remove it and the filament is stuck in there good. I'll reinsert the core and thermo later so I can run it up and remove the nozzle.
Similar to my old aluminum block I found the core stuck in the block and it appears to have done something to the finish of the block (you can see a bit in the first pic). Other than heating up the block so I can remove the nozzle and heat break I think I'm going to call this core "spent" and order a new one (will get a new thermo as well to be safe).
RE: Rebuilt extruder and now having load and extrusion issues
your nozzle looks to be not screwed in far enough before the heat break was adjusted. spec is 1/4-1/2 turn from seating in the block. yours looks to be a turn or more from seating.
are you sure the e3d nozzle installation procedure was followed exactly?
- in bare block - screw in nozzle till seated and then back out 1/4-1/2 turn
- screw in heat break till seated against nozzle
- heatsink should be fully seated on heat break
- PTFE should be fully seated in heat sink and good practice is to put a lock clip under the fitting
- heat hot end to 285C and tighten nozzle while holding block
the end result should be a filament path that is smooth from the heat break to the nozzle with no gaps for filament to lock on to
RE: Rebuilt extruder and now having load and extrusion issues
your nozzle looks to be not screwed in far enough before the heat break was adjusted. spec is 1/4-1/2 turn from seating in the block. yours looks to be a turn or more from seating.
I won't claim "exact" since I seem to have 250 rather than 285 stuck in my head, but "probably good enough".
As it happens I didn't have to heat it up to remove the nozzle and heat break. While fiddling with it nozzle came loose and I was able to remove the parts. Shown here are the bottom of the heat break and top of the nozzle:
Neither shows any sign of escaping plastic to suggest that they were not seated against each other nicely. The nozzle looks about as I expect when filament doesn't get retracted and I expect getting hit with the heat gun will clean most of that out. I can't speak to the looks of the heat break since I've never had filament stuck quite like this before.
@david-a66, screwing the nozzle back in without the heat break and then reversing a bit makes it look the same as that pic you were commenting on. I think it might be the reflective nature of the polished block that is making it look farther out than it really is.
RE: Rebuilt extruder and now having load and extrusion issues
Once you get those cleaned out it'd be good to have a look inside if there are burrs, gouges or other deformities that could restrict flow.
RE: Rebuilt extruder and now having load and extrusion issues
The nozzle position is a bit far out compared to ideal E3D photos - but honestly having the heat break a quarter turn deeper is probably beneficial to avoiding the dreaded heat break jam. Either way - I doubt it's the issue.
What I do see is two colors/tones of filament in the nozzle. One outer layer, and one inner layer. If that outer layer isn't melting while the inner layer is melting ... points to that "something hard in the nozzle" cause.
As Vintage said - once everything is cleaned out - try running a piece of sharp edged filament through the heat break feeling for any rough spots in the walls. A metal burr from manufacturing is always a possibility. I doubt every part is visually inspected at that level.
RE: Rebuilt extruder and now having load and extrusion issues
Cleaned things out this evening. Apologies for no pics, I just couldn't get good shots of value.
I'm used to the nozzle looking full but really just being a bubble. It was full this time! Once clean and cool (pro-tip, don't have your metal tools you are going to use for cleaning in the line of fire from your heat gun...) it looks good and dragging my metal picks across the interior didn't detect any snags or rough areas.
The heat break is still an unknown. After getting the majority of the filament out I noticed what appears to be burn/singe marks where the PTFE seats into the heat break. When I touched it with a pick, however, it just brushed away almost like a super thin fabric. Unfortunately I was unable to recover any to examine further.
The next issue I had was that it did not clean out nicely. I think that was mostly due to the awkwardness of using small tools on a hot object, but there were definitely bits that were super stubborn to remove. I think I got it all clean, but I'm not positive. Either I didn't or there are indeed some rough areas on the interior. Unfortunately I can't get enough light in there, my eyes are too old, and the magnifier I have isn't strong enough for me to get a really good look at what I'm seeing. It does not appear to be green and it's a different color/texture from the rest of the bore though. Assuming it is a non-smooth bore, it's nothing that should cause a jam directly, but I could see it impeding things with partially melted plastic and even potentially impacting the heat characteristics (not much, but maybe enough to harden the filament just enough to clog). I could move cold filament through with no issues though.
I threw another heat break into my order for a new heater and thermo just so I'd have a spare, so I'll be able to compare it and probably just use the new one to be safe.
Now I guess I just twiddle my thumbs until sometime next week 😥