Print issue knocking

[Claude]

Hi
I’m new to 3d Printing
I have a problem with 2 issues
1) My print is fine for the first 50 layers or so, but after that its almost like its over extruding and make like little bumps in the print so when to hot end moves over the print it bumps on the little lumps.
2) Also after my feeder stepper motor makes a clicking noise like its feeds more PLA that what its can handle at the hot end
I someone can please advise
Thanks from Sunny South Africa

[roon4660]

I'm not a printer guru but I do know that when you are asking for help you should supply details of your printer, slicer and filament to help the gurus decide what is probably going on. All the best from not so sunny Montreal.

[Claude]

Hi Roon4660
I have a Ender 3 v2 with PLA filament
I have ultimate Cura 4.8 as my slicer
I install yesterday a BLtouch as I had problems with a uneven glass bed this solved my problem with the bed leveling.
I was wondering is this is not due to humidity in the air that my filament is compromised.

[Geit]

Hi
I’m new to 3d Printing
I have a problem with 2 issues
1) My print is fine for the first 50 layers or so, but after that its almost like its over extruding and make like little bumps in the print so when to hot end moves over the print it bumps on the little lumps.
2) Also after my feeder stepper motor makes a clicking noise like its feeds more PLA that what its can handle at the hot end
I someone can please advise
Thanks from Sunny South Africa

Well, 1 and 2 are linked together. When the extruder is skipping, it means the filament inside the nozzle is under pressure and cannot out. If it can, it comes in masses and it looks like over extrusion, but it is just the filament which was stuffed into the hot end before.

So the main problem you have is clogging. You are not mentioned if that is a small tall print or a wide tall print, so I must guess. And you did not mention the print temperature, ether.

My guess is that your temperature is to low. The heat block is unable to maintain the temperature constantly, so it goes below and above the melting point. You should take a look onto a temperature graph. e.g. when using OctoPrint. If it fails always at the same height, it could be a broken cable, which should be shown at the graph as a drop.

The other thing causing the temperature being to low temperature is the height. If you print the first layers the nozzle is more or less next to the build plate, which heats the air over the bed and prevents the heater block from cooling down, but when you get higher than the block cools down faster and the heater is using intervals to heat.

So it may drop below the proper melting point, heats up and melts again, causes the blobs, cools down, blocks and heats again and so on. Try to increase your temperature by 5°C and see if that change something. A good temperature of PLA filament to print is usually around 210°C-215°C, even so the package says 180 to 220°C. 180 is for very slow prints only and even if that works for normal speed prints, it may cause trouble depending on the use case, like in your case. And you for sure want not print at the temperature edge, when an open window can cause a print to fail.

A third potential issue would be the teflon tube in the heat break. This can be damaged due to high temperatures or filaments with particles like fibre or sparkles. So if you cranked your hotend to 250+°C for some time in the past it may got damaged and need a replacement. It basically causes a smaller channel for the filament, so it is required to be more fluid to pass. You can compensate it by printing at higher temperatures of around 220-235 to increase the filament flow, but I would recommend replace the ptfe tube or the entire heat break in such case. (I used a broken one for about 12 Month without any issues at 235°C because I am just lazy bastard )

[Larry]

Hi
I’m new to 3d Printing
I have a problem with 2 issues
1) My print is fine for the first 50 layers or so, but after that its almost like its over extruding and make like little bumps in the print so when to hot end moves over the print it bumps on the little lumps.
2) Also after my feeder stepper motor makes a clicking noise like its feeds more PLA that what its can handle at the hot end
I someone can please advise
Thanks from Sunny South Africa

A picture of the print would be helpful. Hard to tell what the exact problem is based on your description. As they say a picture is worth a thousand words 😀

[roon4660]

I should have remembered to add that. Indeed a picture can be worth a thousand words.