RE: Surface Problem with big plate
Thank you for your answer!
So it is because the frist layer warped upwards if you say that it comes from the bottom?
As many people in this thread have stated, if the first layer is less than ideal, you will see adhesion issues, so that’s a massive piece of the 3D printing puzzle.
To answer your question from above, you are correct. On a large print, even with a perfect first layer, there is a chance of the print warping, a little, or a lot. And if the print begins to warp, even slightly, it can have a negative effect on subsequent layers; the taller the print and the more layers that are put down, the greater the negative effect on the final top layer(s).
The printer is a ‘dumb’ machine and simply makes the movements the GCode tells it to. As layers are being put down, any area that’s warped is arching upwards, causing the layers above that area to become increasingly compressed, because they’re getting closer to the extruder, but the extruder doesn’t know that so it keeps printing the layers where it’s told to.
The taller the print, the sooner the compression becomes obvious. At some point, the extruder may ‘crash’ into the layer and cause the printer to stop with a crash error message. With a less tall print, the problem may show up in the final top layer, or two. With a very shallow print, you may not see a top layer issue at all.
In your case, the final top layer was over-compressed as it was being laid down and the print head ‘plowed’ through the material as it was being extruded, leaving the rough, wavy texture you see. This is similar to the texture you’ll get when you adjust you first layer Z height too low, because exactly the same behavior is happening: the print head is too close to the surface it’s printing on. The rest of the top layer looks fine because it was flat on the build plate and the top layer was put down at the correct level in 3D space. I hope this makes sense.
Of course, dialing in the proper Z height is key. But even then, warping is possible. There are a variety of methods to increase the first layer adhesion including glue stick and other products. There are plenty of threads on this topic so I’ll leave it at that. Also, a super clean build plate is essential to a good first layer. IPA alone is typically not enough to insure a clean surface. Again, plenty of forum topics on this as well.
Hope you get it sorted quickly. Enjoy your printer!
Cheers