New way to reduce print times  

RE: New way to reduce print times

No, Prusa staff rarely visit these forums.  Why not email to Prusa directly?

RE: New way to reduce print times

You can post feature requests up on the Prusa github pages where the devs might see it. More often than not, these sorts of things turn out to already be implemented, or have been tried and rejected. Rather than being all secretive about it, why not simply describe it here for discussion? If you're hoping to cash in, you really should consult a patent lawyer. The community in general, and Prusa in particular have no qualms about giving credit where due. They regularly call out contributes on their code pages.

RE: New way to reduce print times

Fair enough I guess I can always refer back to the post in the future.

The idea is to use say a .2 nozzle (should scale up as well to .4 etc) and rather than print the entire layer at the same height, have the outer walls print twice at .1 building a smooth shell that is .2 in height

Then have the infil go in and fill at .2 (or if using a .4 have infil at full height).

I cannot see how it would cause issues for the print head as the way I see it the infill would be no different than if the outer skin was printed at .2 in the first place.

It would be interesting to see how it affected the print time of a larger object using a .8 nozzle with outer walls printed at .2

I know the slicer has variable layer heights already but that still prints the entire layers at the choose height.

Let me know what you think? 

Shane

RE: New way to reduce print times

This has been done. You're still constrained by the nozzle size, so it only works if your double-height layers are still blow roughy 80% of your nozzle size, which in turn limits your normal layer heights. It's in PrusaSlicer now. 

RE: New way to reduce print times

I was on mobile. Here's a more complete answer:

Enabling Print Settings->Infill->Reducing print time->Combine infill every X layers has the effect you described. Here's the setting:

The limitation is that your combined infill layer heights are still limited to 80% of the nozzle size or less to ensure good adhesion. Any higher and extrusions will have a round cross-section that doesn't provide as much surface area to adhere to adjacent layers. This in turn limits your external perimeter heights to a fraction of that. With a 0.4mm nozzle, your infill could be printed at 0.32mm but your outer perimeters are limited to 0.16mm (assuming you want nice even multiples). If you want to use combine more than 2 infill layers, the perimeter heights drop proportionally. This has the effect of increasing overall print times as you're reducing layer heights, then offsetting that somewhat with this strategy.

Here's what it looks like in action:

It's not a bad idea, and I don't meant to be discouraging. The time gains aren't particularly worthwhile in my experience. A 40mm cube that normally prints in ~1h33m drops to ~1h27m in the slicer estimate. These are usually close.

Oddly enough, this is the 3rd time I've seen someone with a "super fantastic idea" turn out to be exactly this same feature once they explain it. Don't feel hesitant about suggesting and discussing these sorts of topics. There's a wide user base with a lot of deep experience here that is happy to kick around ideas. When you get a good one, posting it up on the GitHub pages is your best bet.