CTC 3D Printer thunking on Extrusion HELP PLEASE!

Hello Everyone,

My new CTC 3d printer has been upgraded to Sailfish 7.6. It seems to operate fine testing basic functions. HOWEVER! lol. It's thunking upon extrusion both during prints and while feeding filament loading.

It will extrude about 1 to 3 mm of filament fine with no issue then thunk thunk thunk and ripple the filament then do fine again and rinse wash repeat that process over and over again.

I have tried replacing the extrusion wheel with a spare I had. I went from stainless stell to brass. Not sure that helps but I was trying to eliminate issues as the stainless stell one has teeth very close together.

That is also thunking. It is seated very tight and does not appear to be loose.

Any suggestions? It has a shitty feeder on the stepper motor for extrusion. The wheel that the filament glides on is not adjustable and sits pretty close.

Is it maybe not calibrated? Maybe the setting is off in the firmware?


Thanks

UPDATE!

It appears to be thunking using 1.75 mm PLA as well. However the Left extruder seems to be working fine with no issues at all.

I'm just not sure what to do here.

So at 190 C its thunking on PLA and at 220 to 230 C its thunking on ABS. It is trying to pull on filament and slowing feeding but seems to be slipping and will cause ripples. I'm clueless here.

Here is a youtube video showing my Raft that was printing. I'm desperate for help.

[www.youtube.com]

In the video it looks like you use far too much extrusion.
If the extruder can't transport you have several issues to check:
1. Does the filament move freely through the extruder and nozzle if you push by hand?
If you can't push by hand (with the motor off of course) it usually means something is not right.
2. Does the extruder damage the filament?
If there are big marks from holding the filament, those can and will get stuck on the way to the nozzle.
3. Is the current set properly on the driver?
If the current is set too low the extruder will miss steps and cause the clicking noise of jumping filament.
If the current is far too high the motor might make noise but worst: Once the driver overheats it will shut down for a short period, release the motor and you lose steps and won't extrude filament.
4. Feedrate vs nozzle diameter and speed...
If you exceed what the nozzle can spit out properly you build up pressure inside the nozzle.
If everything is tightly sealed the filament has nowhere to go and the extruder fails to transport until the pressure drops.

Does it thunk if you have the nozzle raised above the bed and tell it to extrude manually?

---

Newbie with Folgertech 2020 i3.

Quote
Downunder35m
In the video it looks like you use far too much extrusion.
If the extruder can't transport you have several issues to check:
1. Does the filament move freely through the extruder and nozzle if you push by hand?
If you can't push by hand (with the motor off of course) it usually means something is not right.
2. Does the extruder damage the filament?
If there are big marks from holding the filament, those can and will get stuck on the way to the nozzle.
3. Is the current set properly on the driver?
If the current is set too low the extruder will miss steps and cause the clicking noise of jumping filament.
If the current is far too high the motor might make noise but worst: Once the driver overheats it will shut down for a short period, release the motor and you lose steps and won't extrude filament.
4. Feedrate vs nozzle diameter and speed...
If you exceed what the nozzle can spit out properly you build up pressure inside the nozzle.
If everything is tightly sealed the filament has nowhere to go and the extruder fails to transport until the pressure drops.

To answer those questions

1. yes and no. It moves freely but it is tight. I have ordered a new feeder that will allow me to tension it without replacing the whole system. so that may help things.Otherwise I can push it in with a bit of force
2. not really it does show teeth marks when I take it out of the extruder but its not broke or cracked.
3. yes it should be. I haven't changed anything and the extruder seems to operate fine without filament in it
4. have no idea tell me what to do there. I have no clue where to even start with that.

Quote
msaeger
Does it thunk if you have the nozzle raised above the bed and tell it to extrude manually?

yes it does. it can be hanging anywhere and thunk. Everything is tightened down I put a new top plate on it to see if that stopped it and also a new extrusion wheel. Neither worked. It is still thunking.

It will extrude a little just fine absolutely no issue then it will thunk a few times about 3 to 5. Then extrude normally again.

From your status report I take it that you already tried a few things...
But you say you have marks on the filament, try to adjust the tension on your extruder like this for a try:
Loosen the tension as far as possible.
Grab the filament with your fingers and turn the wheel by hand - if the filament is not pulled through your finger increase the tension until it does.
You want the tension so it is just enough to safely transport the filament, everything more and you can damage and deform the filament.
The marks you see can get caught on the way down, that is why so many people prefer teflon liner.

You can also take the hotend out and just push some filament through it without the nozzle screwed in.
This way you determine if there is anything that might cause the trouble.
Fresh filament should go through with no problem but if you use a piece that went through the extruder and already has the chew marks you will notice if it moves much harder.
Especially towards the end of PLA rolls this can be a problem as the stuff curls up badly.
If you notice a big differenc ebetween fresh and chewed filament try to smooth the inner surface of hot and cold end as well as the heat break.

Quote
Downunder35m
From your status report I take it that you already tried a few things...
But you say you have marks on the filament, try to adjust the tension on your extruder like this for a try:
Loosen the tension as far as possible.
Grab the filament with your fingers and turn the wheel by hand - if the filament is not pulled through your finger increase the tension until it does.
You want the tension so it is just enough to safely transport the filament, everything more and you can damage and deform the filament.
The marks you see can get caught on the way down, that is why so many people prefer teflon liner.

You can also take the hotend out and just push some filament through it without the nozzle screwed in.
This way you determine if there is anything that might cause the trouble.
Fresh filament should go through with no problem but if you use a piece that went through the extruder and already has the chew marks you will notice if it moves much harder.
Especially towards the end of PLA rolls this can be a problem as the stuff curls up badly.
If you notice a big differenc ebetween fresh and chewed filament try to smooth the inner surface of hot and cold end as well as the heat break.

Currently there is no way to adjust tension. CTC makes a fixed extrusion wheel and "tension" wheel. They sit on rods and can not be adjusted. I have ordered a new one for both extruders so I can adjust tension as needed.

Currently it is only thunking on the first layer. I am thinking it may be trying to wave bond something that doesnt need to be. I printed a 20MM cube and it printer flawlessly. And it only thunked while printing our the raft. After that it was smooth as butter. its very weird.

In that case it is not weird at all, just a really crappy extruder

Get a proper one or print one and forget about the thing that can't be adjusted.

Quote
Downunder35m
In that case it is not weird at all, just a really crappy extruder

Get a proper one or print one and forget about the thing that can't be adjusted.

The extruder and printer are actually one of the best on the market right now. the print quality exceeds an ultimaker once its up and running. I bought some tensioners that fit it without heavy modification so it should work well hopefully.