Noob needs help. My printer is sick and I don't know treatment

Noob needs help with unsusable printer. Print keeps failing and now just plain stops extruding midprint
Creality CR6-SE
My printer nor longer functions properly.
Recently I changed the Hotend Kit 24V with Bowden tube on my printer

I am printing a Bell Tower and have printed the first 3 of 5 parts. (Picture 1). Prints are great.
I am now trying to print the Bell Yoke Platform and after 4 attempts sill get failures of a different kind. I get prints that start out fine and after a while it either stops extruding while the hotend goes throught the motion of going back and forth with nothing coming out. Or, this morning, the second picture below where I have a filament mess AND hotend goes back and for the with no filament coming out.
There is no clog in the hotend and no melted filament in the nozzle.

Information about settings.
.4mm nozzle
Using Creality slicer and Cura 4.9
Failed print details :
Tried .12, .16, .2 quality
Tried changing speed from 30mms to 50mms
Infil 5%, 20%, 30%
Heat temp from 200deg to 210 deg
Using Value PLA from 3DPRC. This is my 4th spool of this product without any problem
Tried using Materio3D Translucent PLA 1.75mm
Tried rotating model 90deg on plate in slicer
Tried putting model on side and using tree support
Opened the extruder to clean the gear

Out of ideas. Don’t understand what is happening.
20210522_082528

20210522_081040

do you hear clicking when it’s not extruding anymore filament?

Yes : on and off during printing

So that’s likely the extruder trying to feed filament and slipping. On mine, I would heat the nozzle and try to push filament through if I can’t then there is a clog and I have to clear that if I can then It’s an extruder problem. Given your failures on the latest part, it looks like it may have under extruded when It failed so my money is on a clog.

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So is mine, clicking extruder and signs of under-extrusion sound like a clog to me.
I would double check where the PTFE meets the nozzle.

Well… Hmmmm I did check for a clog and there seemed to be none. I also used cleaning filament befor my last attempt.

I just cheked again and no clog. I am at a loss to understand what is going on. I made sure the cog in the extruder wad nice and clean before I started.

I had also chhanged the boeden tube (sp?) with a tube that came with a tube cutter. Is seemed a little tight so maybe it was another source of problem. could try that. Is the length of the tube important? What woud be the proper length?

Sometimes if there is a lot of retractions in a short period of time the heat will spread up to where the Bowden tube is and start to melt filament in there. it makes it had to push through. so you see any evidence of that on the end of the tube where it goes into the heatbreak? Sometimes a little plastic can squeeze out if there is space between the tube and the heat break too.

There is a lot of back and forth on that particular piece. will try it once more…

If not will try printing sometihing else and see if I get the dame result.

what are your retraction settings? Do you get any stringing at all?

AFTER you’ve had this problem, when you pull the filament out of the nozzle, does it have a bulb on the end of it, like this:

This photo resulted from a fan that had a tiny thread of filament stuck in it which prevented it from turning. Everything prints fine for a while but the heat gradually creeps up the hot end to the point where filament is starting to melt inside the Bowden tube. At some point retractions will pull the molten part of the filament high enough into the Bowden tube where it’s still cooler. The molten plug then solidifies against the walls of the tube cutting off the flow of filament. The print head, has no way of sensing this and keeps printing. Pretty much exactly the symptoms you described. Also, since the plug is actually inside the Bowden tube, your nozzle will not appear to have a clog (because it doesn’t).

Check that your hot-end fan is spinning.

If your prints are failing after a period of time this is most likely heat creep. If you have eliminated the the parts cooling fan blowing onto the hotend cause the temperature to drop, I would suggest swapping out your hotend fan. Even if it appears to be spinning fine it may not be cooling the hotend down enough causing the filament to soften before it should and then jamming up the hotend.

I’m going down a different route. I had an extruder extrude fine stop completely and then sometimes start again after printing air for a while creating a rats nest. This was inconstant not every print but most. I never had a clog.

It turned out to be the stepper over heating and stopping working mid print.
large prints it would cool down and start again and small prints would either finish or stop towards the end and not start.

Replacing the stepper solved the issue.

Thanks for the input, all, it is nice to know some people have similar experiences. I have verified all suggestion that I could. Your indications allowed me to, I think, resolgve the issue.
After making sure there were no clogs, cleaning with cleaning wit filament just in case, I changed the wonky filament tube (bowden ?) which would cause the filament to sometimes snag when I pushed / pulled a piece of filament, made sure the tube was inserted far enough and no gap between it and the nozzle I gave it one final shot. While observing the extruder on a regular basis and an uneasy night’s sleep ( the print took 22 hours with tree support, 15% infill, .16mm layer height) I was finally able to print the missing part for my tower.

Took almost half a spool of filament and 6 attempts. Here is the demonic print. Wizzy the Wiz Wizard is just there for comparison of size. He also likes bell towers. To think such a flimsy piece caused so much trouble.

20210523_203005

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oh yeah that looks like a tough print for sure

I know I’m a little late to this party but I see that the previous prints would have had little retraction however the one that was failing initially would have had a lot more retractions going on. For some reason Cura has default 6.5mm of retraction setup for most of its machines, I usually drop this to about 3.5 or 4 depending on the Bowden setup, I will start at 3.5 run a stringing test and increase until it stops stringing. Bear in mind there has to be zero movement in your Bowden fittings and the blue clips need to be installed. Direct drive I’m at about 1.5 - 1.8mm retraction.

If on retraction the filament gets pulled too far into the throat it may get stuck and cause what will look like a clog, however when you heat up the nozzle again and push it through it will appear to work just fine. Took me a while to figure it out on an ender I had.

I’d say a clog as well if you experienced clicking (slippage of the extruder). Often the clog is not a hard jam, but the filament gets only partially extruded if there’s a gap in the Bowden tube/nozzle junction. It behaves like a clog but when you investigate it’s not there because it came out when you removed the filament. If this is true, it will eventually form a hard jam. I’d square up the hot end side of the tube and try again. This is also presuming that you’ve done a PID on the new hot end at installation.

Newbie here. Shortest Bowden tube possible with no kings or sharp bends. clips in couplers to prevent any tube movement. Filament wiper to help prevent dust from creating drag on filament and clogging or restricting nozzle flow.

welcome @vernonmr hope to you see you here often. Don’t forget to share your favourite prints.