You have 4 problems caused by 2 thing.
First the minor thing:
You levelled slightly lower on the newer print so the first layer is underextruded. This also means the first layer didn't make as good contact so the part was able to warp a little. These are not a big deal and can be fixed by levelling more carefully probably with the nozzle hot (the nozzle expands when it is hot).
The major problem:
Well you have over extrusion on one of the lower layers -0 maybe layer 5 or so, and then you have it again on the layer at the first "top" section about 1/3 of the way up the part. ALL of the other areas look pretty good. This overextrusion causes blobs when the filament explodes out of the over pressurized nozzle and also causes extra stringing due to too much pressure in the nozzle.
So what causes the overextrusion? And why only in two vertical areas? It's almost certainly related to the Z screw.
Home the Z axis, then disable the servos and turn the z screw by hand. Turn it until you have moved at least the height of this part. Notice if there is a sticky spot. Turn the Z screw back the other way until you're head touches the limit switch and repeat a few times. Try to notice:
1) Is there a sticky spot or two?
2) Watch the Z Nut carefully - that big huge nut that is embedded into the Z stage. Does it slip around suddenly at all?
3) Consider putting more grease on the Z stage
4) Does the Z stage hit anything? Is there something that the stage hits on it's way down? Maybe some wires? Look all around the edge and under the Z stage for any obstacles that might slow it down briefly.
If none of this shows you anything you could try experimenting with pronterface or cura to move the Z stage with the stepper. Listen carefully for any noise changes. Consider 1-4 above during this.
A good test print for you would be a rectangular box that is 2cm by 2 cm in X and Y and 20cm tall. Slice and print that at .1mm layers (to show off the problem more) and also make darn sure your layer cooling time is enabled and set to at least 5 seconds.
Basically you need to fix the Z but if you are in a rush you could simply change your layer height to .2mm and you might not get such severe overextrusion.
Recommended Posts
nick-foley 5
It's definitely over-extruding. You can tell by the ridges between your infill on the top layer. Over extruding also just tanks your print quality because retraction never works properly. It does sound like you might have some dirty nozzle/clogging issues, but those could also be due to the overextrusion which may have been grinding your filament, which can then cause clogs when it makes it to the hotend. If I were in your situation, I would:
- Change your filament diameter in Cura to reduce extrusion by around 20% (It's much easier to work your way up from under-extrusion than it is to work your way down from over-extrusion, because unless you're measuring your parts with calipers, slight over-extrusion is hard to detect)
- Open up the filament drive and pull out all of the filament that is in the bowden and hotend, discard it.
- Reassemble the filament drive with fresh filament, and increase drive spring tension 1-2 full turns.
- Reduce your initial layer thickness to .2 or .15. Too thick of a first layer will make it harder to diagnose other problems.
- Send a print with a large skirt with many lines. Adjust the bed height by manually turning the Z screw until you get good skirt lines coming down, and then micro-adjust with the leveling screws until the skirt layers are uniform across the bed.
If none of that worked, I would probably try to clean out the nozzle. But, speaking from experience, hot end disassembly is a can of worms that often leaves you in a worse place than you started. So be careful.
Link to post
Share on other sites