Newbie 3D printer here, working with my 15YO son so both of us can get experience with 3D printing. I’m a Hardware/Software Engineer so I’m comfortable with technical topics, just new to 3D printing. We have a brand new Lulzbot Mini (wanted to spend our time actually printing rather than assembling someone’s kit). My son needs it for his various hobbies, and I need it for some work-related plastic models.
We are using Cura, as shipped on the USB stick with the printer.
We purchased some MakerGeeks PLA because PLA is supposedly a good starter material. We also purchased some Taulman 618 nylon for the work models I need. We’ve tried both so far and are seeing some odd behavior. We have tried multiple off-the-shelf prints as a starting point and they’re all exhibiting some/all of the following, so I don’t think it’s a problem with the print file.
The printer is doing its cleaning cycle, measuring the print bed, etc. so its basic operation seems OK. When leveling, the left front measurement seems to involve more force than the other three, but I see what appears to be an offset correction in the on-screen text so I presume it really is off-level a bit and Cura is adjusting for it.
We did print the Rocktopus with the enclosed short section of HIPS. There were a few imperfections (a “hair” coming off the top of its head at the end, a few bubble-like places here and there) but overall it’s fine. It doesn’t look as perfect as the example Octopus that was included with the printer.
On all prints, even the Rocktopus, it appears like the head makes 1-2 passes around the first layer(s) without extruding any material at all. It literally appears that the printer is wasting time. On the Rocktopus, the result was that the “ring” around the actual part wasn’t fully completed… there was a gap where I suspect the printer thought there was material, but wasn’t. I’m concerned that it believes it’s laying down the first 1-2 layers when it really isn’t. Yes, we carefully installed the filament and did the multiple “10” test to insure we had a good feed going. This also happens on the 2nd, 3rd, etc. prints without changing the filament spool, so even if it was a misfeed on the first one that should not be possible on subsequent prints.
With the PLA, it appears that the nozzle is dragging through the previous layers. This results in a “trough” like layer, with high sides and a low center, as the nozzle melts through the previous layer and displaces that layer’s material to the sides.
I can imagine these two behaviors might be related. If the Z axis is “off”, then it might not extrude at first and then believe the table is lower than it really is, causing the nozzle to drag through the previous layer(s).
We’ve looked through the settings and can’t find anything that appears to control or adjust this sort of behavior. (As a side note, we also looked for something that allows the first layer to have a separate temperature, something suggested in other forum posts, and can’t find such an option in Cura.)
Any advice will be greatly appreciated. Thank you!