How to fix the issue about gaps

[Crcic 0]

Recently I found there are several gaps on the shell, I tried different temperature between the 210 to 230, but it dosen't work.

By the way, I use ultimaker PLA filament.

[Labern 774]

This is under extrusion.

What Printer do you have? Cant give advice if I dont know what you are using as there are many causes of this.

[Crcic 0]

I'm using Ultimaker 2 and Cura

This is under extrusion.

What Printer do you have? Cant give advice if I dont know what you are using as there are many causes of this.

 

[Labern 774]

The Main Cause of this is the PTFE coupler. (the white part under the sprint in the hotend.)

After a while It starts deforming and causes under-extrusion.

The way to see if this is an issue it to remove it and visually inspect it.

It could be that you are just trying to print to fast. What speed are you printing at?

another cause could be incorrect feeder tension / slipping.

I would suggest you read THIS and THIS

[Crcic 0]

Usually, 50-70mm/s.

I find the main issue is the feeder wheel will go back sometimes.

The Main Cause of this is the PTFE coupler. (the white part under the sprint in the hotend.)

After a while It starts deforming and causes under-extrusion.

The way to see if this is an issue it to remove it and visually inspect it.

It could be that you are just trying to print to fast. What speed are you printing at?

another cause could be incorrect feeder tension / slipping.

I would suggest you read THIS and THIS

[Labern 774]

Yeah the feeder skipping back will cause under-extrusion in the area that it skipped back.

It normally skips back if the speed is to high for the temp. Or if there is something causing to much pressure built up like a blocked nozzle or deformed PTFE Coupler.

Try a few Atomic pulls to clean the nozzle as well.

[Crcic 0]

I tried several times cleaning nozzle, but it doesn't work.

Also I test PTFE Coupler, I can use material to get through without any resistance.

I am so confused about solving this issue.

Yeah the feeder skipping back will cause under-extrusion in the area that it skipped back.

It normally skips back if the speed is to high for the temp. Or if there is something causing to much pressure built up like a blocked nozzle or deformed PTFE Coupler.

Try a few Atomic pulls to clean the nozzle as well.

[Labern 774]

Layer height?

Speed?

Temp?

Nozzle Size?

[Crcic 0]

layer height 0.16

speed 60

temp 230

nozzle size 0.4

Layer height?

Speed?

Temp?

Nozzle Size?

 

[zoev89 73]

If you are sure that it is not a blocked nozzle or deformed PTFE coupler and extrusion by hand is smooth. Check you bowden tube it there is nothing inside, sometimes some strands of PLA get in there when you change material. You can also manually try to push some material through at the side of the extruder when it is not holding on to the material.

[frederiekpascal 193]

@Crcic You should give another fresh spool of PLA a try. I had so much troubles with some spools of PLA, you don't want to read that story .

I always print between 20mm/s and 50mm/s, you can try to lower your print speed too and see how much it differs.

Good luck, it's a true adventure!