The Five Settings That Actually Matter
Last lesson was what a slicer does at a high level. This one's the practical part: you open the software, there are about 400 settings staring at you, and maybe five of them matter for a beginner. I'm going to tell you which five and what to set them to.
I know that's a bold number to promise. I've been wrong about smaller things. But I've sliced a lot of prints at this point, and almost every failure or win traces back to one of these five.
1. Layer height
This is how thick each layer of plastic is, measured in millimeters. Most slicers default to something like 0.2mm. Leave it there for now.
Thinner layers (0.12mm) look nicer, more detail, smoother curves. They also take a lot longer, because the printer has to lay down twice as many passes to reach the same height. Thicker layers (0.28mm or up) print fast but look rougher, like you can see the topographic lines of the print.
For a beginner: 0.2mm. It's the setting everybody uses for a reason. Don't touch it until you have an actual reason to, like a print that needs fine detail or one you need done in a hurry.
2. Infill percentage
Infill is the internal structure inside your print, the stuff you don't see unless you cut it in half. Most objects don't need to be solid plastic all the way through. That'd waste filament and take forever.
15 to 20 percent infill is the standard for most things. That's enough structure for a phone stand, a bin, a bracket. If you're printing something that's going to take real load, like a bracket holding actual weight, bump it to 30 or 40. If it's decorative and never gets touched, you can drop to 10.
I run most of my household stuff at 20. The garage pegboard bins, the drawer dividers, all 20 percent. Good enough strength, doesn't waste plastic, doesn't waste time.
3. Print speed
Slicers will let you crank speed way up. Don't, not yet. A beginner printer running too fast skips steps, meaning the print head moves faster than the plastic can keep up, and you get blobby corners, ringing, or a print that just falls apart mid-job.
50 to 60mm/s is a safe range while you're learning your machine. Once you've got some prints under your belt and you know how your printer behaves, you can experiment with going faster. Elijah found out the hard way that you can push speed to 7x normal for something you need done in an hour, and it'll technically hold together long enough to turn in for a school project. I don't recommend that as a general practice. I recommend it as a "when your kid needs a project done the night before it's due and you have zero other options" practice.
4. First layer settings
This is the one I harp on more than any other, and I'll say the opinion straight out: slow down your first layer. Everybody wants their whole print to go faster. The first layer is the whole print. If it doesn't stick right, none of the rest matters, because you'll end up with a spaghetti mess or a print that pops off the bed halfway through.
Most slicers have a separate speed setting just for the first layer, usually defaulted slower than the rest of the print already. Don't override that to save time. I run mine even slower than default, something like 20mm/s for that first layer. Costs you maybe two extra minutes. Worth it every time.
5. Supports
Supports are scaffolding the slicer prints under any part of your model that would otherwise be printing into thin air. Anything with an overhang past about 45 degrees needs support or it'll sag or fail outright.
Turn supports on for anything with an arm, a bracket shape, or an overhang you can picture failing. Turn them off for anything basically flat or box-shaped, because you'll just waste plastic and time removing scaffolding you didn't need. This is a judgment call at first. You'll get a feel for it after a dozen or so prints.
Where this shows up in real life
I printed a little wall mount for Madison's retainer case a while back. Simple shape, low detail, no reason to overthink it. 0.2mm layer height, 20 percent infill, no supports needed because it's basically a flat bracket, first layer slowed down so it'd stick to the print bed clean. Took maybe 45 minutes total. Been mounted by her sink for months now.
Before that mount existed, her retainer went missing about once a week. Under a bed, in a backpack, wherever retainers go to hide. Since I printed the mount and labeled it, it hasn't gone missing once. That's not a complicated print. It's five settings, dialed in sensibly, solving an actual problem in the house. That's most of what this hobby is, honestly.
Before next time
Open your slicer and find these five settings before you print anything else — layer height, infill, print speed, first layer speed, and supports. Just locate them, get comfortable with where they live in the menu. Next lesson we'll slice something together.