Which Infill to choose?
There are a dozen different infill patterns. How do you choose which one to use?
RE: Which Infill to choose?
There are a dozen different infill patterns. How do you choose which one to use?
Maybe this will help
https://help.prusa3d.com/en/article/infill-patterns_177130/
Tank you very much!
RE: Which Infill to choose?
there are also three places you can have infill.
top layer, bottom layer and inside the model.
if you don't have a preference try the default values....
I tend to use gyroid for internal infill, and octogram spiral for the face side a lot of the time. 
this is octogram spiral in the top layer
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Which Infill to choose?
Yep, @@clarmrrsn's link is the definitive source for PrusaSlicer infills. Like @joantabb I used to prefer gyroid but I find myself using adaptive cubic infill more and more often, which for larger models feels a bit faster.
RE: Which Infill to choose?
I've been meaning to use/try adaptive cubic on some of the next larger objects I do, but I keep forgetting to change it from the gyroid that I usually use.
RE: Which Infill to choose?
There's another very topic thread right now: https://forum.prusa3d.com/forum/prusaslicer/do-you-have-to-enable-adaptive-cubic-infill-somehow/
When you select adaptive or support cubic, pick the HIGHEST amount of infill you want to see, and it will scale down from there. When I started using it, my knee-jerk approach was to pick the lowest amount assuming the infill would increase toward the sides/top respectively. That's how I read the description, and I didn't understand why it didn't seem to being do anything. Hard to see any effect below 10, 15% infill, 40% seems to work well.
RE: Which Infill to choose?
@fuchsr
Adaptive Cubic sounds like a good option, need to give it a try.
Tank you very much!
RE: Which Infill to choose?
I select infill based on what I am trying to achieve. If I'm doing something decorative, I'll consider how the infill shows through the perimeter choices I print. If I'm making something that needs integrity - such as a filament holding arm - I look to whether the infill I choose detracts from or adds to strength.
And as Joan says up top, if I'm doing a top layer or bottom layer - or trying to make a clear print (glass clear) infill matters a ton in getting a usable and attractive print.
Certain infills are horribly weak - take gyroid - no strength added there for either torsion or twist. It's great as a fast fast space filler though - so you may want to choose infill on how fast it prints.
Some infills make the noise on your printer go bonkers - print 3d hexagon at 60% some time - sounds like a rasp. But 3D hexagon makes a print strength very high (both torsion and twist).
I'll do two examples of infill choice. I have a lure pattern looks like a fish (I have several of them). I tend to use clear filaments to print lures when I can because the sparkles that the lines of clear filament make for light show. Add in some gyroid infill just under a 2 perimeter skin, and you get the look of fish scales in the finished print. Gyroid is also super light and airy - which for floating lures is an added bonus.
For the low profile spool arm that I have on the prints library, a single arm that mounts on the top of the Mk3s Frame and accepts the standard prusa spool holder arm bayonet (twist lock arms) - the need is for torsional and twist strength. Since someone might mount one spool at a time, you need to prevent twist or the spool walks off the end of the arm due to sag. If you mount two spools - think 5 lbs of hung weight on the end of an arm about a foot long held by a claw on the end, you need to have rigidity and resist bend. I use 3d hexagon (hexagon is the strongest and most efficient strength shape in nature) - 3D so that the added strength extends in all dimensions (x,y and z). I also cheat a bit - if you have ever printed that arm, you'll notice that an invisible feature is inside the arm - a hollow round tube extends up the whole arm but never shows outside. The benefits the tube adds is the tube shape is hard to bend, and is hard to twist. Combine that with infill strength and 5x perimeters, and that arm is chunky and strong. Doesn't sag when you put a heavy spool on one side (thanks to the torsion/twist tube) and that benefit is reinforced all the way out to the external perimeters of the arm by the 3D hex infill.
Infill - it's not all decorative 😉
RE: Which Infill to choose?
One thing you may run into with picking infill is the amount of memory and cpu it will use while slicing.
I had a problem with a large print when I tried to slice it on my laptop. The gyroid infill at 70% was to much for my laptop and would crash PrusaSlicer.
Lowering the infill % or using grid would slice, but very slowely. On my more powerfull PC it will slice just fine no matter what infill type or %.
The designer of the parts suggests 70% infill. Normally I use less and add more perimeters for strength.
Just something to keep in mind if you run into problems.
RE: Which Infill to choose?
Yeah, 70% is way past what I would usually use. For anything "standard" I'd go with 10 or 15% and sometimes as low as 5. I often print large objects with flat top surfaces (boardgame inserts) that require more infill at the top to provide enough support. Like you, I'd increase perimeters before infill.
But as Dan astutely observed, in the end it depends on what you're trying to accomplish.