Multiple oddities

[Alibert]

The raft is looking fine now.

What remains is to get your temperatures and extrusion right.

Be aware that the temperature that is measured may not be the actual temperature. Depending on the tolerances of the components (and possible downright firmware errors, notably in chinese models) the actual temperature can be off by several degrees (extremes of 20 have been reported).

If you have a temperature measuring capability (lab/multimeter for example), you can first check the heated bed. It may be off too much resulting in too high temps for the polymer you are printing with.

As to the nozzles, there are several multiple-temperature test objects to be found on thingiverse, or you can just print your cube at progressively lower temepratures. For the latter, try going down by 10 degrees at a time. I have found that I could go down to 170 C for PLA on two of my printers and still get good extrusion.

Another possibility is that your slicer settings as to extrusion rate need to be modified as the pictures seem to suggest that it is over-extruding a bit. In your slicer you will find settings for extrsuion multiplier, or you can adjust the diameter of the filament a bit which accounts to the same thing. The slicer uses the diameter of the filament to calculate how many mm of filament to push through the nozzle when moving and laying down plastic. If you decrease the diameter, the slicer will push more mm's (extrude more plastic) and if you increase the diameter setting the slicer will push less mm's (extrude less plastic). It is good practice anyway to always check your filament for actual diameter with digital calipers. The cheap ones you buy at the hardware outlet are good enough for this purpose.

Alternate optimizing printing temperature and filament multiplier/diameter until you get good results. This will give a good reference point when testing other colors/brands of filament. For ABS and PETG you will also need to find specific settings which work well. Most slicers will allow you to save settings for a particular type of filament, so you can quickly revert to another filament when needed.

Also beware that there is a dependence between printing speed and temperature. At higher temperatures the viscosity of the polymer will be lower (less backpressure) resulting in more oozing at lower printing speeds but good results at higher speeds. When you increase the printing speed, you will also need to increase the printing temperature a bit, and vice versa.

With lower printing speeds you will generally get more detail and more true dimensions.

PS: as to the paper levelling, did you do it when the heated bed was up to temperature? If the aluminium is thin, it may buckle and thus add/decrease the height at printing temperature.