EZStruder Skipping

[dsnettleton]

So I just "upgraded" to the EZStruder. Unfortunately, it skips like none other. I've checked and rechecked my wiring, my steps/mm, and everything else I could think of. I'm printing in PLA, which I'd heard that the EZStruder has trouble with. This seems a bit worse than "trouble," though, as I can't seem to get any prints out of it. Cranking up the temperature doesn't seem to help, and the flow appears to be adequate. It's certainly oozing enough. I've tried switching out my nozzle, and the PFTE lining in the hotend. I have a 20mm fan on the PEEK running at full speed. Thing is, I'm not entirely sure the EZStruder is at fault. I'm also having trouble feeding the filament by hand. There's a lot of resistance in the hotend, but I can't determine the cause. Like I said, I'm getting a lot of oozing, and I've double-checked the temperature with a thermocouple, so that's not the issue...

Any help would be greatly appreciated.

[geneb]

You may have a clog in your nozzle. Do you have a different one you can try?

Also, take the hot end apart and inspect the PTFE sleeve. If you over-temped it at some point, it may have shrunk a bit and could be causing the binding you're experiencing.

g.

[Eaglezsoar]

You indicate that you have difficulty feeding by hand. Have you tried a different roll of filament?
It's possible you have a bad spool. You've done just about everything that can be done except for raising
the current going to the extruder. Those settings are in the firmware but considering the difficulty you are
having even hand feeding I don't think I would increase the current settings. You don't mention the temperature
you are using but you indicate that you have tried different temperature settings. Until you can get it to feed with
reasonable hand pressure your extruder can't be expected to feed it. Do you have a different spool of filament to
try? Even among the best manufacturers you can get a nasty spool once in a while.

[dsnettleton]

You may have a clog in your nozzle. Do you have a different one you can try?

Also, take the hot end apart and inspect the PTFE sleeve. If you over-temped it at some point, it may have shrunk a bit and could be causing the binding you're experiencing.

I've tried both of those, not only switching out the nozzle, but also the PTFE sleeve as well. I had gone over temperature previously, and the sleeve that came with the hotend was ruined, so I replaced it with a bit of extra PTFE tubing, the same 2mm ID tubing that is used for bowden lines. SeeMeCNC only sells two types of PTFE tubing, so I assumed it would be a suitable replacement.

You indicate that you have difficulty feeding by hand. Have you tried a different roll of filament?

I've tried two different filaments, including one that worked reliably with Steve's Extruder.

[lordbinky]

Is PLA all you have tried with it? If so try lowering your temp (random guess 10°C over the temp it first starts melting), PLA has a weird way of building resistance in the hotend at higher temps even if it's runny .

[dsnettleton]

Is PLA all you have tried with it? If so try lowering your temp (random guess 10°C over the temp it first starts melting), PLA has a weird way of building resistance in the hotend at higher temps even if it's runny .

I've tried everything from 170 to 195. Again, I have verified these temperatures, so I don't expect the problem to be related to them.

[lordbinky]

Damn. Just for the sake of clarity, feeding the hotend by hand through through the PTFE tube does take some effort compared to doing it directly at hotend. The only thing I can think of is just stripping the hotend down giving it a good look over and putting it back together just to say you did.

Just thought of this (yes this is how my thought process works I'm not rewriting my post for new ideas lol). What's your current setting in your firmware? I got mine set fairly high (~200) for the hell of it and there's a fan on it, so it's not getting hot, it is just being excessive. Definitely make sure it's at least 180 for troubleshooting it.

If that does it, make sure to check your retract speed. I have to have my set low, relative to other filament types, or else the EZstruder can eat through it with ease.

[dsnettleton]

So this took me a while. The problem ended up being the replacement PTFE tubing, which was (apparently) marginally too short, by about 1.5mm. The reason the issue did not manifest itself immediately upon replacement is that I originally set the tubing in the nozzle, seated all the way down. What happened is that the PLA would heat up and create friction, then pull the tubing back a little bit with every retraction. When the filament was fed back through, the gap between the tubing and the seat in the nozzle would get filled with molten PLA, which would continue to resist the extrusion. My tubing slowly ratcheted up until the nozzle was too full of thick PLA to do anything but ooze.

[Eaglezsoar]

So this took me a while. The problem ended up being the replacement PTFE tubing, which was (apparently) marginally too short, by about 1.5mm. The reason the issue did not manifest itself immediately upon replacement is that I originally set the tubing in the nozzle, seated all the way down. What happened is that the PLA would heat up and create friction, then pull the tubing back a little bit with every retraction. When the filament was fed back through, the gap between the tubing and the seat in the nozzle would get filled with molten PLA, which would continue to resist the extrusion. My tubing slowly ratcheted up until the nozzle was too full of thick PLA to do anything but ooze.

A little difference of 1.5mm caused all those problems and time to troubleshoot. Bummer but you had the perseverance to figure it out. I wish there was a chart of the different Hot-Ends
produced by SeeMeCNC that listed the exact lengths of PTFE required for each. If co-conspirator John or another busy beaver at SeeMeCNC is reading this, perhaps you can add this to line number 156, 649 of things to do.
Glad you got it fixed, dsnettleton.

[geneb]

There's only ever been ONE hot end. The _nozzles_ have changed. The length of PTFE tubing has changed *once*. That change happened when they went from the "acorn" style nozzle to the more pointed type. The latest generation of nozzle hasn't changed the "throat" length of the nozzle at all.

g.

[Eaglezsoar]

There's only ever been ONE hot end. The _nozzles_ have changed. The length of PTFE tubing has changed *once*. That change happened when they went from the "acorn" style nozzle to the more pointed type. The latest generation of nozzle hasn't changed the "throat" length of the nozzle at all.

g.

Good info Gene, is there a chart somewhere that lists the different lengths of PTFE? I have seen user "estimates" here on the forum but I do not remember
seeing an official blessed by the folks at SeeMeCNC sizing info.