"The filament is regularly stuck in the piece below - ISOLATOR GUIDE. It is therefore very difficult to remove the blockage here. But for the time being succeeded.
But the printer does not print properly.
As you can see in the photo below. These circles are not at all round."
If the printer does not print a correct circle, this may be the following cause.
CIRCLES ARE DISTORTED
When circles are printed with flat sides or similar then your printer may have loose motor belts. You can fix this by loosening the X & Y MOTOR MOUNTS, pull the motor assembly down so the motor belts (180mm x 6mm T2.5 BELT) are tight and then fasten the MOTOR MOUNT again.
The axes may also not be aligned correctly.
Follow these instructions:
Make sure to install the printer firmly on a stable surface. If not, adjust the feet until the printer is stable.
Next, move the printer head back and forth, left to right with one hand. Make sure not to force, as you should be able to do this without moving the printer itself. If the printer moves while trying to move the printer head, then the axes are not aligned correctly and the printer head is jamming itself.
How to solve, see under the photos for clarification.
Concerns clogging the printhead:
It is recommended to use VERTEX PLA filament. Print temperature is 200 - max 210 ° C.
Try to also do not mix with other filaments such as ABS, PETG, etc.
Also use this software: https://www.velleman.eu/downloads/files/vertex/software/vertex-3d-printer-repetier-host-1-6-2.zip and install it with full administrator rights.
In this software you use the Cura engine, to slice the 3D objects. In principle, the settings for PLA are preset for the best print quality.
Also check the PTFE tube in the in isolator guide, so that it has the correct distance 23mm.
If this is too small, then the specified size. the 10ths are very important, this can lead to blockage.
Also depending on how much the printer must retract the filament while printing the 3D object.
Cut the piece with a clean cutter. The cuts must be clean, straight and as vertical as possible! It can help to hold the cutter against a flat object.
Very important!! => Do not use a piece that is more than 0.25 mm smaller than 23 mm, or more than 0.25 mm LARGER than 23 mm!
You can try this a few times with the supplied PTFE-TUBE until you are satisfied with the cut part. Make sure you have 75cm of the PTFE TUBE.
If you are not sure whether you can cut the piece so precisely, you can possibly cut a slightly larger piece and sand the piece further to size with a piece of sandpaper. Make sure that the ends are flat and vertical. Clean the tube thoroughly after sanding!
If all this still does not work, you can also bring the printer back to the store where it was purchased.
So we can check it, repair it.
Hope to have informed you sufficiently with this.