Sequential printing - big time differences
I use sequential printing because I *think* it's generally better to concentrate on one part at a time rather than skipping back and forth between them.
But ... and I have a recent extreme example ... you'd think that sequential would be QUICKER - all those steps between parts omitted ... but it's generally not the case, according to Prusa Slicer. And today I looked at printing a 4-part musical flute. Slicer says about 4 hours in sequential, 2 hours normal. What?? Any ideas why the big difference?
File is attached. For sequential print go to print settings -> output options -> complete individual objects. And don't forget to "arrange" the parts on the bed after enabling it.
I have not yet attempted to print this, either sequential or normal.
RE: Sequential printing - big time differences
The file was not attached, but I assume that the objects you print have small cross sections -- e.g. the flute sections standing upright?
When you print individual small objects, there must be enough time for the prior layer to solidify before the next layer is printed on top. PrusaSlicer will slow down the overall print to achieve that (rather than introduce explicit wait times). But when you print multiple objects in parallel, each layer takes much longer anyway, so there is no need for the artificial slow-down.
RE: Sequential printing - big time differences
Can't add it to the post above anymore -- but to be specific, the relevant PrusaSlicer setting is under Filament > Cooling > Slow down if print layer time is below ... seconds.
RE: Sequential printing - big time differences
Apologies for the lack of attachment, remedied here.
OK, very interesting, & thanks. I quite understand about the need for prior layers to solidify, but I thought that was a few seconds at most. Your conjecture is correct that the parts have small cross-section and upright, so that must indeed be the reason. That makes me no less surprised at the big difference.
RE: Sequential printing - big time differences
Apologies for the lack of attachment, remedied here.
OK, very interesting, & thanks. I quite understand about the need for prior layers to solidify, but I thought that was a few seconds at most. Your conjecture is correct that the parts have small cross-section and upright, so that must indeed be the reason. That makes me no less surprised at the big difference.
You can't attach .3mf files directly; the forum software silently drops them. Pretty stupid for a 3D printing forum... 😉 If you zip the file before posting, it should come through.
The default setting for the minimum layer time for PLA (Filament > Cooling > Slow down if print layer time is below ...) is indeed just 8 seconds with my PrusaSlicer set to the Core One. Maybe it was set longer for a different material or printer you use?
RE: Sequential printing - big time differences
Really? !! OK I'll zip it, although not really necessary, I think.
So ... I can see my "slow down if ..." is set to 8 seconds as you observe. Also interestingly I observe that if I hover over the '8' box until the help text box appears, THAT says that the default is 5 seconds. Why the difference, and should I think of trying 5 maybe?
Anyway, not to worry, I'll probably stick with the std slicer settings and go and slice non-sequentially.
RE: Sequential printing - big time differences
If you look at the layer times for the non-sequential print setting, they are only around 16 seconds for all four parts of the flute combined. So slowing each individual section down to the 8-second minimum for a sequential print would roughly double the total print time -- in line with what you observe.
RE: Sequential printing - big time differences
Another tip is to go to Preview and change the view to Actual Speed under "Legend". You can see how the speed differs between regular and sequential printing, and hot it compares to nominal values set in the print profiles.
Formerly known on this forum as @fuchsr -- https://foxrun3d.com/
RE: Sequential printing - big time differences
Thank you both. I've not used preview extensively; I have had a good look at layer times there, also speed and actual speed. All very informative.
I've not found an easy way to list individual layer times: the vertical slice slider on the right shows them in a box if you hover the mouse pointer over. Maybe on a part with fewer layers it would be easier, but even with my hi-res mouse I can hardly step between two without skipping one.
Overall my impression is that the slicer is quite conservative in actual slice times and that there could be scope for manual speed-up. But I'm not going to go there just now; it's been educational. Thanks.
RE: Sequential printing - big time differences
I've not found an easy way to list individual layer times: the vertical slice slider on the right shows them in a box if you hover the mouse pointer over. Maybe on a part with fewer layers it would be easier, but even with my hi-res mouse I can hardly step between two without skipping one.
That's what I do to look at individual layer times; not sure whether there is a more easily controlled way to read them. To get to the 16 seconds I mentioned above, I just set the slider to somewhere "pretty high up, but all four sections still being printed", read off the total time and number of layers until that point, and divided them.
RE: Sequential printing - big time differences
I've not used preview extensively
It's a good habit to get into. Even a quick scroll through the model will show you issues quickly and avoid print failures. I just wish the PrusaSlicer would remember your selections (such as Show seams). Has been requested many times on Github but Prusa must be too busy fixing FW 6.4 issues...
Formerly known on this forum as @fuchsr -- https://foxrun3d.com/
RE: Sequential printing - big time differences
FWIW, I always use sequential printing when printing multiple flexible material parts like PEBA Air (for example). Otherwise you get these messy strings between the parts that can be annoying to remove post print.