Well, a week a go I was trying to print a 3D squared box with rounded borders. At the beginning everything was working right. So, I went for a walk for about 1 hour. When I came back, I found 3D print had failed. The hotend could not pass a border, created due to print error, and it was going up and down hitting the border each time. I said, what a shame lets stop it, and print other thing.
Then the nightmare came. I tried to print another box with edged borders. For my surprise, I found, hot end was skimming the surface, the surface of the first layer was lumpy. When it began with second layer, hotend hit the lumpy first layer and broke it. This happened every time I tried. I said ok, lets print a box without a flat base, only walls. Although, first layer was not ok, I printed without more issues.
How did I to solve it?
- Change hotend with a new one. I found oil at the contact place with the heater. Very suspicious!!! I cleaned it, but It did not solve anything.
- Machine calibration. It did not solve anything.
- Manual Bed Trimming. Solved skimming surface, but not lumpy first layer.
- Tightening Heat Block Screws. When I removed hotend, and unscrewed the Heat block I found several issues. 1- Screws were partially loose. 2- The back side of the heat block was very dirty with oil 3- Screws at the back side of the Heat block were partially loose. So, I cleaned the oil of the heat block, and tighten the screws. This fixed it.
Now I am operative, and back to print, with first layers, better than the first day. I expect this can help you if you are in a similar case.