Surface Issues on Large Prints (PETG, 0.8mm Nozzle)  

Surface Issues on Large Prints (PETG, 0.8mm Nozzle)

Hello all,

I'm new to the forum, although I’ve been lurking for a while and learning a ton from the advice and tips posted here – big thanks in advance to all the contributors and gurus!

While I don’t have a Prusa, I’m hoping someone here might be able to help me dial in my Creatbot D1000. It’s been a bit of a nightmare out of the box, but I’m determined to make it work. I’ve already made some key improvements – particularly to the bed setup.

The print volume is 1000 x 1000 mm, split into four 500 x 500 zones. Unfortunately, the build quality isn’t great, and bed levelling has been a major challenge. I’ve now added a 4mm thick tempered glass sheet, which has helped tremendously – I can actually get prints going now without immediate failures, which is a huge step forward!

I’ve just completed a large print, and while it finished successfully, I’ve noticed serious issues with the top surface quality. There are missing areas, visible bumps, and poor finish overall – although oddly, some other areas of the print look fine.

Here are my current print settings:

Nozzle: 0.8 mm

Layer height: 0.32 mm

Infill: 15%, Cubic Subdivision

Perimeters: 2

Top solid layers: 3

Bottom solid layers: 2

Speed: 60 mm/s

Retraction: 2 mm at 40 mm/s, minimum travel after retraction 1 mm, “wipe while retracting” enabled

Material: PETG

Temp: 240°C nozzle / 70°C bed

Filament diameter: 1.75 mm

Extrusion multiplier: 0.95

Extrusion width: 0.96 (calibrated via test prints)

If anyone has experience with large-format printers, PETG settings, or issues with inconsistent top layers, I’d really appreciate your thoughts. I’m not sure whether this is under-extrusion, cooling, or something else entirely.

Thanks in advance!