My interest in this topic is related to printing large objects that I intend to use around the house. I chose an Ender 3 Max (advertised to do 300 x 300 x 320 mm) and Cura.
After some trial and error I managed to print my first large project: a flat (~390 x 290 x 5 mm) divider for my freezer drawers, made of 2 overlapping parts designed in Blender and assembled together with snap-fit joints. I successfully printed out 2 copies and then I ran into a "not sticking to bed" problem that required a reevaluation of most adhesion parameters previously used.
Here is what works for me right now (brass nozzle 0.4 mm; PLA filament 1.75 mm; bed cleaned with 70% isopropyl alcohol, not 99%):
- Layer height: 0.2 mm
- Initial layer height: 0.2 mm
- Top/Bottom thickness: 0.8 mm
- Printing temperature: 200 °C
- Printing temperature initial layer: 210 °C
- Build plate temperature: 60 °C
- Build plate temperature initial layer: 70 °C
- Print speed: 40 mm/s
- Initial layer speed: 5 mm/s
- Enable print cooling = False
- Build plate adhesion = True
- Build plate adhesion type = Brim (8 mm)
- Z Offset = -0.05 mm [using 'Z Offset Setting' plugin by fieldOfView]
- Enable draft shield = True [Experimental setting]
- Draft shield X/Y distance = 10 mm
Setting the offset to -0.05 mm after bed leveling is important as it seems to enhance bed adhesion. Enabling the draft shield is a condition to avoid warping; not sure whether it works by preventing drafts or by providing additional mechanical stability to the printout but I find this feature particularly useful in my case.
The parameters above give me a nice-looking printout. The problem is that it takes 25 h to print one part and 21 h the other. This is still acceptable for now as I only need 4 copies for this project. Soon I will start a new project, where I need to print 6 different parts of a ~900 x 600 x 250 mm object. I feel that, with the inevitable trial and error required for optimization, my next project may take months to complete.
Any suggestions?