Will not Extrude PETG but works with PLA

Bambu Lab X1 Series Troubleshooting
1

Hi All

I have had my X1C for around 3 weeks now. I have only been printing PLA up until a couple of days ago when I decided to try Bambu Basics PETG.
For some strange reason the printer extrudes and prints PLA perfectly, But the PETG will not extrude. The AMS feeds the filament to the extruder with no issues, but as soon at it tries to feed to the hot end I just get a clicking noise from the extruder. Its like the gears are grabbing the end of the filament and then slipping off. I have stripped it down to make sure there’s now clog and its all clear. I have cut the end of the filament to a point but still no go. however if I replace the PETG with PLA the printer works perfectly.
Has anyone else experience any thing like this? or can anyone help me solve the issue.

Many Thanks in advance

2

Welcome to the forum.

When you are replacing the PLA with PETG are you reslicing the model with the PETG profile so the required higher nozzle temperatures are adjusted? PETG can’t be printed with the same sliced gcode for PLA.

2 Likes
3

Hi JonRaymond, thank you for your kind welcome and reply.
I have a profile for PETG which runs the nozzle at a higher temperature. The problem is I dont think the filament is getting to the hot end. If I load the filament and then remove the bowden tube from the extruder the filament pulls out the extruder with no effort at all. I believe this means the filament isnt being passed into the gears to drive it into the hot end. if I attempt the same with PLA i have to rotate the yellow gear to remove the filament.

Many Thanks

4

Try to push the PETG down manually. The gears might be too tight and cannot fully grasp to the end of the filament. Use your hand to push it.

5

Hi Henry140.

Thank you for the suggestion.
I tried that last night but despite pushing the filament manually whist pressing the feed button on the screen it just makes a clicking sound and the filament will not pass through. It just bends at the entrance.
If I looses the screw that adjusts the tension on the spring, could this help or will it affect other filament types?

Many thanks.

6

Hi Smurph,

You have probably looked at the easy things already but just to be sure:

  • What is the nozzle temp when you hear it clicking? If that is the root cause, check Min/Max temps.
  • Does the PETG have a nice, clean, 90° cut at its end with no deformations close to the end?
  • Did the gears strip material from the PETG, reducing its diameter? That could prevent a fix from being effective.
  • Can you reduce total friction of the filament in the feedline (i.e. reduce PTFE bend radii, shorten PTFE’s)? As a check, try PETG printing from the rear spool holder.

Hope this helps,
Eno

7

Just loosen the screw. The temp should be high enough to melt PETG. You might need to take the extruder apart though because there might be an extruder clog.

8

I had a similar issue with tpu and the A1, the filament wouldnt extrude until i had dried it, then it printed perfectly ,
Drying Settings (Blast Drying Oven) 65 °C，8 h Bambu recommendations for petg

9

You shouldn’t have to touch the extruder gear tension, it should be screwed in as far as it goes standard and the spring tensions.

Have you load the PETG from the external spool? This takes the AMS/buffer out of the equation and may help narrow the issue down. Alternatively, leave the PTFE out and heat up the nozzle to 250c manually on the touchscreen and then press the extrude feeder arrow down (the slider on the right side on the Temp/Axis screen). You should be able to get a better idea if your extruder and nozzle are working.

I have had one time when I swapped out from PLA to ABS and it caused a heat-creep blockage as I’d warmed my Chamber up to over 45c prior. Not saying this is your case but perfect storms happen :)…

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