Explain this to me
I drew up this jig for work at 6 inches. However...I noticed when adding a second one, that rather than doubling the print time, it only increased about 50%.
So after a few changes to the model and reloading from disk, I decided to try two 3 inch models instead of one 6 inch. Lo and behold! It cuts the time by about a third to print the two instead of one 6 inch.
??? haha my theory is that prusaslicer slows the printer to allow sufficient cooling on a small model like this but you guys tell me.
RE:
My first guesstimate: while you're putting down pretty much the same filament volume, since you've removed half the z-axis movement the printer doesn't have to stop extruding while it waits for each of those extra layer steps in the taller model.
But the logic of these things is complicated and I'm sure there's plenty more that contributes. Great question!
my theory is that prusaslicer slows the printer to allow sufficient cooling on a small model
You are correct. The slicer notes the time required to return to the same XY position one layer higher and delays if it will be too soon for the layer to solidify. This slows the print for tall, narrow or tapered prints but, as you noticed, the time can be recovered by printing another object or another instance at the same time.
There are settings to adjust this but while it can sometimes pay to lengthen the delay shortening it is almost always a mistake.
Cheerio,