First setup and your first print

This is the chapter where the box stops being a box and becomes a machine that makes things. You have a printer (or you are about to), you have filament, and you are itching to press a button and watch plastic appear. We will get there. But the difference between a first print that makes you grin and a first print that turns into a stringy mess almost always comes down to one skill: laying down a good first layer. So we are going to spend most of our time there, calmly, and then run a real print together.

If you have not picked a machine yet, glance back at Chapter 2. If you are unsure which plastic you are loading, Chapter 3 has you covered. We are assuming PLA here, the friendly beginner plastic.

Before you power on: a quick safety word

A 3D printer is a small robot with a hot tip. Nothing here is scary if you respect it, so let me be plain about the three things that can hurt or surprise you.

  • The nozzle gets hot. For PLA it sits around 200 degrees Celsius (roughly 390 Fahrenheit). That is hot enough to give you a real burn. Treat the metal end as "do not touch" whenever the printer is on or recently used.
  • The bed can be hot too. The print surface (the "bed") often warms to 50 to 60 degrees Celsius for PLA. Not skin-blistering, but warm enough to notice.
  • It moves on its own. Once a print starts, the head and bed move without warning. Keep fingers, hair, and sleeves clear of the moving parts.

One more habit: do not leave your very first prints fully unattended. Stay in the room, at least for the first layer and the first several minutes. Once you trust your machine and your settings, you can relax. At the start, watch it. If something looks wrong, you can stop it before it becomes a problem, and Chapter 7 is your rescue guide when it does.

Getting set up: assembled vs kit

Printers arrive in two broad flavors. An assembled (or "pre-assembled") printer comes mostly built; you unclip some foam, attach a gantry or a screen, plug in a few cables, and you are close to ready. A kit printer arrives as parts and asks you to build it, which takes a couple of patient hours but teaches you the machine from the inside out. Either is fine for a beginner. Follow the maker's own instructions for the build, because the steps differ from model to model, and there is no generic shortcut worth trusting over the manual that came in your box.

Whichever you have, do not skip the "remove all shipping screws and foam" step. Printers are often locked down for transit, and a forgotten transit screw will fight every move the machine tries to make.

Where to put it

Pick the spot with a little care, because it affects print quality more than you would guess.

  • A sturdy, level-ish surface. A printer that wobbles transfers that wobble into the print as ripples. A solid desk or table is ideal. It does not need to be perfectly level like a billiard table, but it should not rock.
  • Ventilation. Even PLA gives off a faint smell while printing. A room you can air out is plenty; you do not need a lab fume hood for PLA, but do not run it in a sealed closet you sleep next to.
  • Away from drafts. This one surprises people. A cold breeze from an open window, a door, or an air conditioning vent can chill one side of a print faster than the other. Uneven cooling makes the plastic shrink unevenly, and the corners can lift off the bed. That lifting is called warping, and a steady, draft-free spot prevents most of it.

The one skill that matters most: a good first layer

Here is the single idea that separates frustrated beginners from happy ones. The first layer decides whether the whole print survives. Everything above it is built on that foundation, so if the bottom does not stick properly, the print can pop loose halfway up and turn into spaghetti.

Two things make a first layer good:

  1. Adhesion. The first layer has to grip the bed and stay put for the entire print, which can be minutes or hours.
  2. Squish. The nozzle should be just close enough to the bed that it gently presses (squishes) that first layer of melted plastic flat. Too far away and the plastic lays down as loose round noodles that barely touch. Too close and the nozzle scrapes and starves the flow.

Get the squish right and adhesion usually follows. So most of "learning to print" is really "learning to set the gap between the nozzle and the bed." That gap is what bed leveling is all about.

Bed leveling, explained from zero

"Leveling" is a slightly misleading word. You are not making the bed perfectly horizontal with respect to the floor. You are making the gap between the nozzle and the bed the same everywhere, and setting that gap to about the thickness of a sheet of printer paper. If the front-left corner has a big gap and the back-right corner has none, the first layer will be loose in one place and crushed in another. Even gap, even first layer.

There are two ways your printer might do this.

Manual leveling and the paper test

Many beginner printers have adjustment knobs (usually four, one under each corner of the bed). You turn the knobs to raise or lower each corner until the nozzle-to-bed gap is even. The classic way to judge that gap is the paper test:

  1. Heat both the nozzle and the bed to your printing temperatures first, because metal expands a little when warm and you want to level under real conditions. (Many printers have a "level" or "auto home" menu that handles the moving for you.)
  2. Send the nozzle to one corner.
  3. Slide a normal sheet of paper between the nozzle tip and the bed.
  4. Adjust that corner's knob until you feel a slight drag on the paper. Not so loose the paper slides freely (gap too big), not so tight the paper crumples or will not move (gap too small). A light, consistent scratch is the target.
  5. Repeat at every corner, then go around a second time, because adjusting one corner can nudge the others.
PAPER TEST FEEL

  too loose        just right        too tight
  --------         ----------        ---------
  paper slides     slight, even      paper buckles
  with no drag     drag / scratch    or won't move
   (raise bed)        (good)         (lower bed)

Auto bed leveling (ABL)

Some printers probe the bed themselves. A sensor near the nozzle touches or senses many points across the bed, builds a little map of the high and low spots, and the printer compensates in software while it prints. This is called auto bed leveling, or ABL. If your machine has it, you run a menu option, the head taps its way across the bed in a grid, and you are mostly done. It is genuinely easier.

Even with ABL there is usually one thing left for you to set: the Z offset.

Z offset and first-layer height in plain terms

"Z" is the up-and-down axis. The Z offset is a single number that tells the printer how far above the bed "zero" really is, which decides how squished your first layer comes out. Think of it as a fine volume knob for squish:

  • Lower the Z offset (nozzle closer to bed) for more squish.
  • Raise the Z offset (nozzle farther from bed) for less squish.

On a manual printer you mostly set squish with the corner knobs. On an ABL printer the leveling is automatic, but you dial in this one Z offset number until the first layer looks right. Either way, the goal is identical: a first layer that is pressed flat just enough to fuse and stick.

Don't be confused. Bed leveling and Z offset are not the same thing. Leveling makes the gap even across the whole bed (no corner higher than another). Z offset (or first-layer height) sets how big that even gap is, which is the squish. You can have a perfectly level bed that is still set too high (loose noodles everywhere) or too low (scraping everywhere). Level first so the bed is fair, then tune the offset so the squish is right.

Bed adhesion: helping the plastic grip

A level bed is half the battle; a clean and suitable surface is the other half.

Clean it. The biggest, most common adhesion killer is grease, and the main source of grease is your own fingers. Skin oils leave invisible fingerprints, and plastic slides right off them. Wipe the bed before printing. Warm water with a drop of dish soap, dried with a clean cloth, works well for most surfaces. Some people use isopropyl alcohol. Whatever you use, then try not to touch the print area with bare hands.

Know your surface. Three common bed surfaces behave differently:

  • Textured PEI (a removable spring-steel sheet with a slightly rough coating) grips PLA well when warm and leaves a pleasant matte finish on the bottom of your print. Very forgiving for beginners.
  • Smooth PEI grips well too and leaves a glossy bottom. It can grip too well sometimes, so let it cool before removing the print.
  • Glass gives a mirror-smooth bottom and is easy to clean, but PLA does not always stick to bare glass on its own, which is where glue comes in.

Glue stick. A plain washable glue stick (the kind for school) rubbed thinly on the bed gives the plastic something to hold. It is most useful on glass, or on any surface where prints keep lifting. It also acts as a release layer on some surfaces so prints pop off cleanly once cool. A thin, even coat is all you need.

Skirts and brims. Your slicer (the software from Chapter 5) can add a helper outline around your model. A skirt is a loose loop printed near the model but not touching it; its job is to get the plastic flowing before the real print starts, and to give you a preview of your first-layer squish. A brim is a flat collar printed attached to the model's base, like a hat brim, to add grip and fight warping. For a first print a skirt is normal; if corners lift, a brim helps.

Loading filament

Now the fun part. Loading PLA is simple once you know the order.

  1. Preheat the nozzle first. Set the nozzle to your PLA temperature and wait for it to reach it. Why preheat? The old plastic inside the nozzle is solid at room temperature. Trying to push filament through cold plastic just jams or strips the filament. Heat melts what is inside so new filament can flow.
  2. Trim the filament end at an angle to a clean point so it feeds smoothly.
  3. Feed it in. Push the filament into the extruder (the gear-driven mechanism that grips and pushes filament). Many printers have a "load filament" option that runs the gear for you; otherwise squeeze the lever and push by hand.
  4. Wait for plastic out the nozzle. Keep feeding until a thin string of melted plastic comes out the tip. When you see steady, clean plastic emerging (often you will see the color change as the new filament arrives), it is loaded. Wipe away the little blob with tweezers, not fingers.

Changing or unloading filament

To swap colors or remove a spool: preheat the nozzle again (same reason, the plastic must be molten), then use the "unload" option or gently pull the filament back out once the gear releases it. Always heat before you pull. Yanking cold filament is how you damage the mechanism.

Temperatures for PLA

Rough starting points for PLA, and they are starting points:

  • Nozzle: around 200 to 215 degrees Celsius.
  • Bed: around 50 to 60 degrees Celsius.

Every brand of filament is a little different, so follow the temperature printed on the spool's label over any number I give you here. The label wins. When you change brands, check the label again.

Your first print

Tradition says your first print is either a calibration cube (a simple 20 millimeter cube that lets you check whether your dimensions come out true) or the famous 3DBenchy, a small toy boat designed to stress-test a printer. The Benchy is clever: it packs overhangs, a chimney, curves, text, and fine details into one little model, so how it prints tells you a lot about how your machine is doing. Plenty of people print one as a rite of passage.

Here is the path from file to object:

  1. Get a known-good test model. Download a calibration cube or a 3DBenchy from a reputable model site. Use a well-known, widely printed file so that if it fails, you know the problem is your setup, not a bad model.
  2. Slice it with a beginner profile. Open the model in your slicer, pick the default or "beginner"/"standard" profile for your printer and for PLA, and let it do the work. We cover slicing properly in Chapter 5; for now, defaults are your friend.
  3. Transfer it. Get the sliced file onto the printer however your machine accepts it: an SD card, a USB stick, or over the network/Wi-Fi if supported. Eject the card safely so the file does not corrupt.
  4. Start the print and WATCH the first layer. This is the important part. Stand there. Watch the lines go down. The first layer is your report card, and learning to read it is the most useful skill in this whole book.

Reading the first layer: good vs bad

As the printer lays the first layer, look closely. Here is what you are comparing:

GOOD FIRST LAYER (top view of the lines)

  ====================
  ====================     lines sit side by side, fused into a
  ====================     solid sheet, even width, slightly
  ====================     flattened, no gaps, sticking firmly
  ====================


BAD: NOZZLE TOO HIGH                BAD: NOZZLE TOO LOW

  ~~~~  ~~~~  ~~~~                  ____________________
  ~~~~  ~~~~  ~~~~   round, loose   ____________________  scraped,
  ~~~~  ~~~~  ~~~~   noodles with   ____________________  translucent,
  ~~~~  ~~~~  ~~~~   gaps between,  ____________________  rough/ridged,
  ~~~~  ~~~~  ~~~~   not sticking   ____________________  nozzle drags
  • Good: the lines press into each other and form a smooth, even sheet with no gaps. Each line is slightly flat on top, not round. It is clearly stuck to the bed. This is what you want.
  • Too high (under-squished): the lines are round like loose spaghetti, with gaps between them, and they do not stick well. Fix: lower the nozzle a touch. On a manual bed, raise the bed corners slightly (smaller gap); with a Z offset, nudge it lower.
  • Too low (over-squished): the plastic looks thin, see-through (translucent), and rough or ridged, and you may hear the nozzle scrape. The flow is being starved. Fix: raise the nozzle a touch. On a manual bed, lower the corners slightly (bigger gap); with a Z offset, nudge it higher.

Make small adjustments. A first layer is sensitive, and a tiny turn of a knob or a 0.05 millimeter change in Z offset is often all it takes.

First print checklist

Run through this before you press start:

  • Printer on a sturdy surface, no draft blowing across it
  • All transit screws and foam removed
  • Bed wiped clean of grease and fingerprints
  • Bed leveled (even gap), paper test or ABL done
  • Nozzle and bed preheated to PLA temperatures from the spool label
  • Filament loaded; clean plastic came out the nozzle
  • Known-good test model sliced with a beginner PLA profile
  • File transferred and selected on the printer
  • You are in the room, ready to watch the first layer
  • You know how to stop the print if it looks wrong

If the first layer goes down like the "good" picture, relax a little and let it run. If it goes down loose or scraped, stop, make one small adjustment, and try again. That loop (watch, adjust, retry) is how every experienced printer learned, and it is faster than it sounds.

When something genuinely misbehaves and a tweak does not fix it, do not wrestle with it blindly. Chapter 7 walks through the common failures and their cures.

Takeaways

  • Respect the heat and the motion: hot nozzle (around 200 C for PLA), warm bed, moving parts. Watch your early prints; do not leave them fully unattended.
  • The first layer decides the print. Good adhesion plus the right squish is the whole game.
  • Leveling makes the nozzle-to-bed gap even; Z offset sets how big that gap is. They are different jobs. Level first, then tune squish to about one sheet of paper.
  • A clean, grease-free bed is half of adhesion. Wipe it, do not touch it, and use a glue stick on glass or whenever prints lift.
  • Preheat before loading so the old plastic melts; feed until clean plastic flows. Always heat before unloading too.
  • Use PLA temperatures from the spool label over any rough number.
  • Print a calibration cube or 3DBenchy from a known-good source, slice with defaults, and watch the first layer so you learn to read good vs bad.

You now know how to make a printer lay down a clean first layer and turn a file into a real object. But we glossed over the step that turns a 3D model into the actual instructions your printer follows. That step is called slicing, and it is where a lot of your control over quality and speed lives.

👉 Next: Slicing 101: turning a model into machine moves.