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Jamming on retract at the Chameleon feed motors

After a few upgrades and some tuning on my Ender 3, I got it to successfully pull the first filament and print the first layer color. I am now having issues with the Chameleon jamming when retracting. It is getting stuck in the feed motors. I have to manually give it a good tug to get it unjammed. I know it's not the printer, because I pulled the feed from my motors and still had to tug while retracing pretty hard to get it to come loose. I have printed and used the alignment tool for the stepper gear. Quick question. Should that be done to both motors? I was hesitance to mess with anything on the side with the bearings as it looked like they were pressure fitted, Any help, as always, is appreciated. I feel like I'm so close. I got excited today to finally see if get a first color out.

10 comments

10 Comments

Thomas Randolph

May 13

Can someone tell me if this is the correct location to adjust the retraction numbers? 425 is the distance from the extruder to the hotend and this is what the MK4 generator created. I changed the last 25 to 30. Also why is it 4 separate 100 commands instead of 1 - 400

Making sure I'm in the correct location.

; retract it back out of the extruder

G92 E0

G0 E-100 F2000

G92 E0

G0 E-100 F2000

G92 E0

G0 E-100 F2000

G92 E0

G0 E-100 F2000

G92 E0

G0 E-30 F2000

G92 E0

las_vegas

May 13

Replying to

Some varients of Marlin choke if the extractor feeds too much at once. Mine doesn't and I changed it to a single number. I would actually take it a little further; Like 450mm. It's not going to hurt anything extracting beyond what's needed.

Thomas Randolph

May 14

Replying to

I think I might have figured out my issue, but not sure how to fix it. After the Tip Shaping, when it retracts, it is getting hung up at the extruder gear when it comes all the way out to the tip for some reason. I can replicate it manually. I have the spring as loose as it will go, but the tip is catching and won't let the chameleon pull it out. I will persist but it is aggravating at this point.

Thomas Randolph

May 14

Replying to

I will try and bump it up to 450, like you said @las_vegas and see if it has enough of a punch to get it free.

Thomas Randolph

May 13

I disassembled the chameleon again and re-aligned the gear. It did appear to be off ever so slightly. I created a test I created with just 4 letters and assigned each one to a different extruder. About as basic as you can get. Seems like it might be a timing thing. Like heh filament is not unloading enough before the retraction starts. I'm gonna mess with those times and see if I can get it to reverse all the way out before chameleon tries to pull.

las_vegas

May 13

Replying to

It's okay to retract more than needed. It will stop once it's fully out of the extruder until the 3D Chameleon starts retracting.

Thomas Randolph

May 13

Replying to

Yeah, I was thinking that too. Just can't figure out if my extruder is not moving fast enough. I checked my steps by extruding 100mm and doing the math and adjusted my steps accordingly.

Thomas Randolph

May 14

Replying to

I'm getting closer. It definitely looks like the filament is catching on the Bowden connection when exiting the extruder on a retract. I was able to get 2 colors to print a first layer last night, but the 3rd borked it up. I think It may be time to work on making a 3DClippy to see if that helps.

las_vegas

May 13

It sounds to me that the feed to the extruder is a little too long whcih would cause the 3DChameleon to grind down the filament a bit before it's drawn into the extruder. This could result in the 3D Chameleon having difficulty drawing the filament back again if that notch is present in the retracted filament.

Bill

May 12

The alignment tool he made is specifically for the extruder side. However, it almost sounds like it's not still not aligned correctly. Check the cam to make sure | on it is pointing at exactly the 3, 6, 9 and 12 o'clock positions when it goes through all 4 colors. If it is, there is nothing wrong with it. But, also make sure the bearings are pressed fully on the bottom and the top... we've seen some on here where they get out of alignment with the C part and instead interfere with the B part, which causes it to not have as much pressure as it should.

Ok... a little explanation. The top part of the 3DChameleon is the "A" part... there are two of them... one on top and one on the bottom. In the middle are two stacks of B/C pairs... those are the two layers that have the bearings and tension springs inside them. The bottom part is the C and it connects to the top part, the B. When the cam rotates, it presses on the C part in an oval channel. The B part has a "flag" that sticks out, which you can see in the very top of the cam system. While, the top one doesn't do anything, the bottom B part actually has an arm on it that sticks out and will hit the flag when it rotates during homing. When it hits it, you'll hear the classic grinding of the homing as the motor stalls. Check the condition of the flag if you see the | on top of the cam not align correctly with the cardinal positions mentioned above. If it's not aligned, it won't be able to apply the proper tension. Ok... that's the cam side. On the motor side, just make sure that the 2mm black spacer is in place and that you use the alignment check to make sure the drive gears are properly centered on the filament paths. If you can pull the filament while the 3DChameleon is gripping the filament, that is not good... the grip should be so tight that you'll spin the extruder motor instead of it slipping. Chris' Basement did a great video on his YouTube channel about how to validate that it is set up correctly. You can find it here: https://www.youtube.com/watch?v=NUYJseo78tI If all else fails, ping me via email and we'll try to figure out where the issue lies.

Bill