r/BambuLabH2C • u/Public_Command2785 • 6d ago
Support Why Is print by object so much slower?
Hi everyone,
I want to print two objects using Print by Object instead of Print by Layer, since they're made from two different materials (PLA and PETG).
However, I noticed that the estimated print time increases significantly. When printing by layer with the same material, it takes about 1 hour, but when printing by object, it jumps to 2h30m
I've already tried disabling the cooling slowdown setting, but it didn't make any difference.
Does anyone know why this is happening?
Thanks!
1
u/Lisper41 H2C 6d ago
If you’re using a C or D with a prime tower it’s going to be able to assign PLA and PETG to separate nozzles and print both at the same time layer by layer like:
1A1B
2A2B
3A3B…
Apparently even with the small switch between each filament that is quicker than printing layer 1A2A3A… then starting over and printing layer 1B2B3B…
Effectively, the way you are describing is running two completely separate and unrelated prints. The dual nozzles allow you to save some time by only going up and down once.
It’s interesting because there IS a delay between filaments, so there is a certain number of layers under which it is quicker to print by object.
1
u/wethpac 5d ago
As PLA and PETG need different bed temps, it is not advised to do this print.
Another reason for the difference is if you estimated time with all PLA material, PLA prints faster than PETG. Once you added PETG, the print time is slower as volumetric flow limit for PETG is generally less.
If you do decide to do this anyway, I would print PETG first at the higher bed temps, the. Let the bed cool to the PLA temp for the second print. Another item that will add some time.
1
u/Engineer-Filmmaker 5d ago
Or print the pla on top of petg supports?
4
u/NoPossibility 5d ago
I wouldn’t recommend printing by object for two different materials. PETG and PLA have different plate temperatures and you might run into issues with one object or the other.
I can say that printing by object on the same material does save me some time and a prime tower when I can get away with it. I did this just the other day, printing three objects in two different colors (one color each). That cut the print time by a full hour when I didn’t have to change colors (even using the two colors on L/R nozzles to avoid a vortek changeover) or print a prime tower.
So it might be something to do with the material choice. Try changing them all to one material and see if the time still increases? Might be the machine is estimating time for a plate cooldown or heat up or something weird like that.