K8200 doesn't print clean lines anymore

K8200 3D Printer K8200 - Issues while printing
1

Hello,

I’ve already searched this forum but i’m not able to find a solution for the issue i’m experiencing.
I didn’t had any issues while printing my first 3 prints.
Now it seems like the filament prints in ‘dots’ instead of in ‘clean lines’.
See pictures:

I already took these steps in order to solve the issue but nothing helps:

  • I checked the nozzle for clogging filament
  • I tried printing on different nozzle and printbed temperatures
  • I experience the issue while printing exactly the same 3D designs that i’ve printed successfully before (so i guess there is no issue with the 3D files)
  • I tried with and without ‘paper-tape’ on the printbed
    –edit–
  • I also tried to modify the filament flow rate. I raised it up to 150% but it’s still printing bad. As I also mentioned above I tried to re-print files (which where already sliced and printed successfully before, so it are exactly the same files with the same settings.)

Hopefully somebody knows what could be the cause of this issue?

Thanks in advance

2

Maybe is bed bed adherence problem ?
reprap.org/wiki/Print_Troublesho … sufficient

3

It might be a good idea to check the level of the bed and recalibrate the Z axis end stop. The nozzle may be too high above the bed for the first layer.

Level the bed with a sheet of paper on the bed to test for equal clearance at all four corners. Then set the z calibration.

You can also turn the Z screw during the print job to manually adjust the first layer height. This is a quick way to determine whether first layer height is the issue.

4

This is just a wild guess.
Did you just mount a new roll of filament?
Are you printing ABS with PLA temps?

Just a thought.

5

First of all; thanks everybody for your replies, much appreciated! :slight_smile:

[quote=“Tag”]Maybe is bed bed adherence problem ?
reprap.org/wiki/Print_Troublesho … sufficient[/quote]
It can be possible, but I’m not that sure because I was able to successful print my first 3 objects.
I apply some paper tape on the glass plate so the PLA sticks to it. (In the beginning it came loose a few times while printing, using paper tape solved that issue.)

[quote=“Dr. Vegetable”]It might be a good idea to check the level of the bed and recalibrate the Z axis end stop. The nozzle may be too high above the bed for the first layer.
Level the bed with a sheet of paper on the bed to test for equal clearance at all four corners. Then set the z calibration.
You can also turn the Z screw during the print job to manually adjust the first layer height. This is a quick way to determine whether first layer height is the issue.[/quote]
I don’t think this is the issue. I checked the bed level with a piece of paper and it’s ok as described in the manual.
I also tried to increase and decrease this bed level but i was never able to print good lines. When I increase the bed-nozzle distance the filament doesn’t sticks to the bed, when I decrease the bed-nozzle distance the filament keeps stucking around the nozzle while moving over the bed (there was too less space between bed and nozzle).
I also tried to modify the first layer height in printer/slicer settings.

[quote=“Wrong Way”]This is just a wild guess.
Did you just mount a new roll of filament?
Are you printing ABS with PLA temps?

Just a thought.[/quote]
I’m printing with PLA.
This is still my first roll of filament, I used the same roll with my first 3 successful prints.
I tried bed temperatures from 50°C to 65°C and nozzle temperatures from 190°C to 210°C.

6

You could try to remove the tape.
put a lite coat of hair spray on the bed and print to it.
However I don’t think this is the problem.
The perimeter came out ok for the most part.
I looks like you are under extruding.
Check the small gear on the extruder make sure the screw that holds it on the motor is tight.
Don’t over tighten it.
Also check that there is some clearance between the gears (if they are to close they will bind)
The nozzle may be clogged but I would do the other checks first the screw is a great place to start as this happened to mine.

7

In addition to the suggestions here already, you might try heating up the extruder, and turn the big extruder gear by hand. How does it feel? Is it pushing the filament through consistently? Or is there a point where the teeth of the hobbed bolt feel like they slip on the filament and it stops coming out? Is it smooth, or is there inconsistency or bumpiness in how much force it takes throughout the rotation?

Some things to check, that have happened to me after many months of good printing, then it got worse:

Slipping small gear on the extruder motor shaft, like Wrong Way mentioned. -Make a mark on the shaft, and on the gear, see if the shaft ever spins without the gear, if so, tighten. You can file a flat spot on the shaft, for the set screw if you want (just don’t get metal bits down inside the motor!)
Chewed up filament clogging up the teeth in the hobbed bolt. -Remove, check, and clean if necessary.
Gunk in the pinch roller bearing, that the hobbed bolt presses against. -Partially disassemble extruder, check bearing is running smoothly, if not, remove, clean, and re-oil.
Gears too close together, making them bind up, there needs to be a little play in the fit. -Move the extruder motor away from the big gear.

It’s easy to pull the hobbed bolt out, and extruder front plate, and check the inner workings of the extruder.

8

[quote=“Processaurus”]In addition to the suggestions here already, you might try heating up the extruder, and turn the big extruder gear by hand. How does it feel? Is it pushing the filament through consistently? Or is there a point where the teeth of the hobbed bolt feel like they slip on the filament and it stops coming out? Is it smooth, or is there inconsistency or bumpiness in how much force it takes throughout the rotation?

Some things to check, that have happened to me after many months of good printing, then it got worse:

Slipping small gear on the extruder motor shaft, like Wrong Way mentioned. -Make a mark on the shaft, and on the gear, see if the shaft ever spins without the gear, if so, tighten. You can file a flat spot on the shaft, for the set screw if you want (just don’t get metal bits down inside the motor!)
Chewed up filament clogging up the teeth in the hobbed bolt. -Remove, check, and clean if necessary.
Gunk in the pinch roller bearing, that the hobbed bolt presses against. -Partially disassemble extruder, check bearing is running smoothly, if not, remove, clean, and re-oil.
Gears too close together, making them bind up, there needs to be a little play in the fit. -Move the extruder motor away from the big gear.

It’s easy to pull the hobbed bolt out, and extruder front plate, and check the inner workings of the extruder.[/quote]

Hi Processaurus, thanks for your answer.
At the moment I don’t have much time to work on the pinter. But I hope to have some time soon so I can have this problem solved.
The issue I noticed a while ago is as you mentioned:
“There is a point where the teeth of the hobbed bolt feel like they slip on the filament and it stops coming out”
I had disassembled the extruder and checked the hobbed bolt but it seems to be ok, all teeths are the same, none of them were damaged.
The bearings are running smoothly but i noticed that the ‘hole’ on the side plates, where the bearing fits in, are a bit too large. So the bearings and bolt are not centered in the middle of the hole, they are a bit loose. I tried to tighten and to loose the screws holding the hobbed bolt but that didn’t solve my problem.
After checking these parts I reassembled the extruder and started printing again, and guess what!? It was printing fine again!.. but sadly, after around 1 hour printing it fails again. Fillament didn’t flow smoothly through the extruder anymore.
If you have any ideas or sugegstions how i can solve this issue they are more than welcome.

Thanks in advance!

9

Level the bed with a sheet of paper on the bed to test for equal clearance at all four corners. Then set the z calibration. 3d printing mumbai pune

You can also turn the Z screw during the print job to manually adjust the first layer height. This is a quick way to determine whether first layer height is the issue.