3D Printing Basics

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3D Printing Basics
Competency 3D Printing
Difficulty Beginner
Time Required 4-6 hours (spread over multiple sessions)
Prerequisites None - complete beginner friendly
Materials Needed FDM 3D printer, PLA filament (1kg), slicer software (free), spatula, flush cutters
Next Steps SimpleBot assembly, 3D Printing for Robotics, CAD Design

3D Printing Basics is your complete introduction to fabricating robot parts using FDM (Fused Deposition Modeling) 3D printing. This tutorial takes you from unboxing a printer to successfully printing SimpleBot components.

By the end of this tutorial, you'll be able to:

  • Set up and calibrate your 3D printer
  • Use slicer software to prepare models for printing
  • Successfully print your first parts
  • Troubleshoot common failures
  • Print all components for SimpleBot
  • Post-process and assemble printed parts

This tutorial is completely hands-on. You'll need a working FDM printer (recommendations below) and basic tools.

What You'll Need

Required Equipment

  • 3D Printer - FDM printer with minimum 180×180×180mm build volume
    • Recommended: Creality Ender 3 V2 ($200-250), Prusa Mini+ ($400), Artillery Genius ($300)
  • PLA Filament - 1kg spool, 1.75mm diameter ($15-25)
    • Color doesn't matter functionally, but white/black are easiest to see layer quality
  • Slicer Software - Free software to convert models to printer instructions
    • Recommended: PrusaSlicer (works with any printer, not just Prusa)
    • Alternative: Cura (more beginner-friendly interface)
  • Computer - Windows, Mac, or Linux to run slicer software

Required Tools

  • Spatula or scraper ($5-10) - Remove prints from bed (often included with printer)
  • Flush cutters ($5-10) - Remove supports and clean up prints
  • Isopropyl alcohol 70-90% ($5) - Clean print bed

Helpful But Optional

  • Calipers ($15-30) - Measure prints to check accuracy
  • Needle files ($10-20) - Clean up holes and edges
  • Glue stick ($2) - Extra bed adhesion for difficult prints
  • Filament storage container ($10-20) - Keep filament dry

Part 1: Understanding Your 3D Printer

FDM Printer Anatomy

Your printer has these key components:

  • Print bed (heated platform) - Where the part is built
    • Heats to 50-100°C to prevent warping
    • Must be level and clean for adhesion
  • Hot end (extruder nozzle) - Melts and deposits plastic
    • Heats to 180-220°C for PLA
    • Nozzle is typically 0.4mm diameter
  • Extruder (filament feeder) - Pushes filament into hot end
    • Bowden tube (tube between feeder and hot end) or direct drive (feeder mounted on hot end)
  • Motion system - Moves hot end in XYZ axes
    • Belts, stepper motors, linear rails
  • Controller board - Computer that runs the printer
    • Reads G-code files from SD card or USB
  • Display - Interface to control printer
    • Start prints, adjust temperature, move axes

First Time Setup (Assembly)

Most budget printers require some assembly. Follow manufacturer instructions, but key steps:

  1. Attach gantry to base - Usually pre-assembled, just bolt together
  2. Install print bed - Connect heated bed power and thermistor
  3. Run cables - Route wires neatly, use cable clips
  4. Install bowden tube - Push into fittings on extruder and hot end
  5. Verify motion - Manually move axes (power off) - should move smoothly with no binding
  6. Check wiring - Loose wires can cause fires! Verify all connections tight

Safety check before first power-on:

  • ☐ All screws tight (especially bed and gantry)
  • ☐ Belts tensioned (not too loose, not too tight)
  • ☐ Wires secured, not touching hot end or bed
  • ☐ No shipping zip ties or packing material left on moving parts

First Power On

  1. Plug in printer and turn on power switch
  2. Display should light up with home screen
  3. DO NOT start a print yet! - Must level bed first

Navigate the menu:

  • Most printers use a rotary knob (turn to move, press to select)
  • Find the temperature display - should show room temperature (~20-25°C)
  • Find the axis movement controls - you'll need these for bed leveling

Part 2: Bed Leveling (Most Critical Step)

Bed leveling is the single most important step for successful prints. The nozzle must be exactly the right distance from the bed across the entire surface.

Why Bed Leveling Matters

  • Too close - Nozzle drags through plastic, clogs, scrapes bed
  • Too far - Plastic doesn't stick, print fails in first layer
  • Uneven - Works on one side, fails on other side

You must level the bed:

  • When you first set up the printer
  • After moving the printer
  • Periodically (every 5-10 prints) to maintain accuracy

Manual Bed Leveling Procedure

You'll need:

  • A piece of paper (printer paper works fine)
  • 10-15 minutes of patience

Steps:

  1. Home all axes - Use printer menu: Prepare → Auto Home
    • Nozzle moves to home position (usually front-left corner)
  1. Disable steppers - Menu: Prepare → Disable Steppers
    • Now you can manually move the hot end
  1. Heat the nozzle (optional but recommended) - Menu: Prepare → Preheat PLA
    • Bed and nozzle expand when hot; level when hot for best accuracy
  1. Position nozzle over first corner - Manually move hot end to front-left, just above bed
  2. Adjust bed corner knob - Turn knob under bed while sliding paper between nozzle and bed
    • Goal: Paper should slide with slight friction (like writing on paper)
    • Too loose? Tighten knob (turn clockwise)
    • Too tight? Loosen knob (turn counter-clockwise)
  1. Repeat for all four corners - Front-left, front-right, back-right, back-left
  2. Check center of bed - Move nozzle to center, test with paper
    • If center is different from corners, repeat the process
  1. Iterate - Go around all corners again. Adjusting one corner affects others slightly

Target feeling: Paper should slide with noticeable resistance but not tear. You should feel the nozzle just barely touching through the paper.

Tip: Some people describe it as "dragging paper over a wooden table" feeling.

Auto Bed Leveling (If Your Printer Has It)

Higher-end printers (Prusa, some Creality models) have automatic bed leveling:

  1. Attach probe or ensure sensor is working
  2. Menu: Prepare → Auto Bed Leveling or similar
  3. Printer probes multiple points on bed
  4. Creates a mesh to compensate for unevenness

Note: Even with auto bed leveling, you still need to set the initial Z-offset (nozzle-to-bed distance).

Part 3: Loading Filament

Preparing Filament

  1. Remove filament from sealed bag (if new)
  2. Inspect filament end - should be cleanly cut (if not, use flush cutters to cut at angle)
  3. Note the diameter: 1.75mm (most common) or 2.85mm (some printers)

Loading Procedure

  1. Heat the nozzle - Menu: Prepare → Preheat PLA (nozzle to ~200°C)
  2. Wait for temperature - Display shows current and target temp
  3. Release extruder tension - Squeeze lever or loosen spring on extruder
  4. Insert filament - Push filament into extruder hole
    • For Bowden tube systems: Push until it comes out the hot end (may take 30-50cm)
    • For direct drive: Push until it comes out the nozzle (just a few cm)
  1. Extrude some plastic - Menu: Prepare → Move Axis → Extruder → Move 10mm
    • Plastic should flow freely from nozzle
    • If not, increase temperature by 5-10°C and try again
  1. Check extrusion - Plastic should come out smooth and consistent, not bubbly or clumpy

Tip: Have paper towel ready to wipe excess plastic from nozzle.

Unloading Filament

  1. Heat nozzle to printing temperature (~200°C for PLA)
  2. Retract filament - Menu: Prepare → Move Axis → Extruder → Move -10mm
    • Or squeeze extruder lever and pull filament out manually
  1. Store filament - Wind onto spool, secure end with clip or tape

Why store properly? PLA absorbs moisture from air, which causes print quality issues (bubbling, poor layer adhesion).

Part 4: Your First Print - Calibration Cube

Getting the STL File

A calibration cube is a simple 20mm × 20mm × 20mm cube used to test printer accuracy.

  1. Search online: "20mm calibration cube STL"
  2. Download from Thingiverse, Printables, or similar site
  3. Save to your computer (file will be named something like `calibration_cube.stl`)

Introduction to Slicer Software

Slicer software converts 3D models (STL files) into instructions (G-code) for your printer.

  1. Download and install PrusaSlicer: https://www.prusa3d.com/prusaslicer/
  2. Launch PrusaSlicer
  3. First-time setup wizard:
    • Select your printer manufacturer (or Generic for non-listed printers)
    • Select your printer model (if listed) or closest match
    • Select filament type: PLA
    • Complete wizard

Importing and Slicing the Cube

  1. Import STL - File → Import → Import STL/OBJ, select calibration cube
  2. Position model - Should automatically be on center of bed
    • If not: Right-click model → Center
  1. Check scale - Model should be 20mm × 20mm × 20mm (verify in right panel)
  2. Configure print settings (right panel):
    • Layer height: 0.2mm (good balance of speed and quality)
    • Infill: 20% (sufficient for test)
    • Supports: None (cube doesn't need them)
    • Brim: Yes (helps adhesion for first print)
  1. Slice - Click "Slice now" button (bottom right)
  2. Review preview:
    • Click "Preview" button (bottom right)
    • Use slider to see layer by layer
    • Check that first layer looks good (should be solid, covering bed area)
  1. Export G-code - Click "Export G-code" button
    • Save to SD card or USB drive

Print Settings Explained

  • Layer height (0.2mm) - Thickness of each layer
    • Smaller = smoother, slower (0.1mm for high detail)
    • Larger = faster, rougher (0.3mm for draft prints)
  • Infill (20%) - Internal structure density
    • Higher = stronger, heavier, slower (30-50% for structural parts)
    • Lower = lighter, faster (10-15% for non-structural parts)
  • Perimeters (2-3) - Number of outer wall layers
    • More = stronger, better surface finish
  • Brim - Extra layer around base (helps adhesion, easy to remove)
  • Raft - Platform under entire part (use for difficult adhesion, wastes material)
  • Supports - Temporary structures to hold overhangs (remove after printing)

Starting the Print

  1. Insert SD card into printer
  2. Clean the bed - Wipe with isopropyl alcohol, let dry
  3. Verify bed level - Do a final check with paper if uncertain
  4. Start print - Menu: Print from SD → select G-code file
  5. Watch the first layer - This is critical!

Watching the First Layer

Stand and watch the entire first layer print. This determines success:

Good first layer:

  • Plastic is squished slightly onto bed (not round, slightly flat)
  • Lines are touching each other with no gaps
  • Plastic is not being pushed around by nozzle
  • Print is adhering firmly to bed

Bad first layer (stop and restart):

  • Lines are round (nozzle too high - adjust bed lower)
  • Nozzle drags through plastic (too low - raise bed)
  • Gaps between lines (too high)
  • Plastic not sticking to bed (bed too cold, dirty, or not level)

If first layer fails: Stop the print, adjust bed leveling, clean bed, try again.

If first layer succeeds: You can leave it to print! Check back periodically.

Print Complete

When print finishes:

  1. Let bed cool - Print will often pop off on its own as bed cools
  2. Gently flex bed (if removable spring steel sheet) - Print pops off
  3. Use spatula - Slide under edge of print, pry gently
  4. Remove brim - Use flush cutters or hands to remove brim material

Inspect your cube:

  • Measure with calipers: Should be close to 20mm × 20mm × 20mm (±0.2mm is good)
  • Check corners: Should be square and sharp
  • Check walls: Should be solid and smooth

Congratulations on your first successful print!

Part 5: Troubleshooting Common First Print Problems

Print Not Sticking to Bed

Causes and solutions:

  • Bed not level - Re-level bed, nozzle should be slightly closer
  • Bed too cold - Increase bed temperature by 5-10°C (try 65°C for PLA)
  • Bed dirty - Clean with isopropyl alcohol
  • Nozzle too far - Lower bed (turn corner knobs clockwise)
  • First layer too fast - Slow down first layer speed in slicer (50% of normal)

Extra help: Apply glue stick to bed for difficult adhesion.

Lines Not Touching (Gaps in First Layer)

Cause: Nozzle too far from bed

Solution: Adjust bed level - turn corner knobs clockwise to bring bed closer to nozzle.

Nozzle Dragging/Scraping

Cause: Nozzle too close to bed

Solution: Adjust bed level - turn corner knobs counter-clockwise to lower bed away from nozzle.

Print Warping (Corners Lifting)

Causes and solutions:

  • Bed too cold - Increase bed temperature
  • Rapid cooling - Close windows, avoid drafts
  • Poor adhesion - Clean bed, use brim or raft
  • Part geometry - Large flat parts warp more (add brim or mouse ears at corners)

Stringing (Thin Strings Between Parts)

Causes and solutions:

  • Nozzle too hot - Reduce temperature by 5°C
  • Retraction too low - Increase retraction distance in slicer (5-6mm for Bowden)
  • Print too slow - Increase print speed slightly

Layer Shifting (Print Offset Mid-Print)

Causes and solutions:

  • Belts too loose - Tighten belts (should twang like guitar string when plucked)
  • Speed too high - Reduce print speed
  • Mechanical binding - Check that axes move freely, lubricate if needed

Under-Extrusion (Gaps in Walls)

Causes and solutions:

  • Nozzle partially clogged - Perform cold pull cleaning
  • Temperature too low - Increase by 5-10°C
  • Filament diameter wrong - Verify slicer is set to 1.75mm (or 2.85mm if that's what you have)
  • Extruder gear slipping - Tighten extruder tension spring

Part 6: Printing SimpleBot Components

Now that you've successfully printed a calibration cube, you're ready for real robot parts!

Downloading SimpleBot STL Files

  1. Navigate to SimpleBot repository (linked from SimpleBot wiki page)
  2. Go to the `stl/` or `3d_models/` directory
  3. Download all STL files:
    • Chassis base and top
    • Motor mounts (left and right)
    • Wheel hubs (2×)
    • Sensor bracket
    • Battery holder
    • Any other structural components

Print Order Recommendation

Start with smallest parts first to gain confidence:

  1. Sensor bracket (~1 hour) - Small, simple, good practice
  2. Wheel hubs (30-45 min each) - Small, verify fit with motor shaft
  3. Motor mounts (~2 hours each) - Test holes fit motors correctly
  4. Chassis base (~4-6 hours) - Large, important part
  5. Chassis top (~3-5 hours) - Can print while assembling other parts

Slicer Settings for SimpleBot Parts

General settings:

  • Layer height: 0.2mm (good balance)
  • Infill: 20% (sufficient for most parts)
  • Perimeters: 3 (strong outer walls)
  • Supports: Usually not needed (parts designed to print without supports)
  • Brim: Use for large parts (chassis) to prevent warping

Part-specific notes:

  • Chassis - Large flat part, definitely use brim
  • Motor mounts - Check hole sizes (may need to adjust scale if motors don't fit)
  • Wheel hubs - Verify fit on motor shaft (may need light sanding)
  • Sensor bracket - Ensure mounting holes align with sensors

Print Time Estimates

Total print time for all SimpleBot parts: 15-20 hours

  • Sensor bracket: 1 hour
  • Wheel hubs (2×): 1.5 hours
  • Motor mounts (2×): 4 hours
  • Chassis base: 5 hours
  • Chassis top: 4 hours
  • Misc brackets: 2 hours

You can print multiple small parts simultaneously to save time.

Quality Check After Printing

For each part:

  • ☐ Verify dimensions with calipers (compare to CAD file or assembly guide)
  • ☐ Check mounting holes - screws should fit (M3 typically)
  • ☐ Test fit with hardware - motors, sensors, PCB
  • ☐ Remove supports (if any) and clean up edges
  • ☐ Light sanding if parts don't fit together smoothly

Part 7: Post-Processing Robot Parts

Removing Supports

If you printed parts with supports:

  1. Use flush cutters to clip large support structures
  2. Break away remaining supports by hand
  3. Use needle file or sandpaper to smooth support scars
  4. Check that surfaces are flat where parts mate

Cleaning Up Holes

Printed holes are often slightly undersized:

  • Clearance holes (screws pass through):
    • Use drill bit slightly larger than screw diameter
    • Drill by hand (twist drill bit with fingers) or with drill
    • Test fit frequently - don't remove too much material
  • Press-fit holes (bearings, nuts):
    • May need light sanding with sandpaper wrapped around dowel
    • Test fit frequently - goal is snug fit
  • Threaded holes:
    • Drill/print undersized (M3 screw needs 2.5mm hole)
    • Use tap to cut threads
    • Or just drive screw directly into plastic (works for low-stress applications)

Fitting Parts Together

Test assembly before final build:

  1. Dry-fit all parts (no glue, no screws)
  2. Identify any interference or misalignment
  3. Sand or file problem areas
  4. Re-test until smooth assembly

Optional Finishing

For a polished look:

  • Sanding - Progressive grits (120 → 220 → 400) for smooth surface
  • Primer and paint - Automotive filler primer hides layer lines
  • Clear coat - Protects finish and adds shine

Not necessary for functional robot parts, but makes them look professional.

Part 8: Assembling SimpleBot with Printed Parts

Once all parts are printed and cleaned up:

  1. Follow SimpleBot assembly guide
  2. Key steps:
    • Mount motors into motor mounts using M3 screws
    • Attach wheel hubs to motor shafts (may need small set screws)
    • Mount PCB and electronics to chassis base
    • Attach sensor bracket at front of chassis
    • Mount line sensors to bracket
    • Connect wiring according to schematic
    • Attach chassis top
    • Insert batteries

Tip: Take photos during assembly to help with troubleshooting later.

Part 9: Maintenance and Care

Printer Maintenance

After every print:

  • Remove print from bed
  • Clean bed with isopropyl alcohol
  • Inspect nozzle for plastic buildup (wipe with paper towel when hot)

Weekly (if printing frequently):

  • Check belt tension
  • Lubricate linear rods/rails with machine oil
  • Check all screws for tightness (vibration loosens them)

Monthly:

  • Re-level bed
  • Check extruder gear for wear
  • Clean fans and heat sinks

Filament Storage

PLA absorbs moisture from air, which causes:

  • Bubbling during extrusion
  • Poor layer adhesion
  • Brittle prints

Storage solution:

  • Keep filament in sealed container with silica gel desiccant
  • Some hobbyists use vacuum-sealed bags
  • If filament gets wet, dry in oven at 40-50°C for 4-6 hours (or use filament dryer)

Replacing Nozzles

Nozzles wear out after 100-500 hours of printing:

  • Abrasive filaments (carbon fiber, wood fill) wear fastest
  • Symptoms: Under-extrusion, inconsistent extrusion
  • Replacement: Heat to 200°C, unscrew old nozzle, screw in new one

Keep spare 0.4mm nozzles on hand ($1-2 each in bulk).

Next Steps

Continue Your 3D Printing Journey

  • 3D Printing for Robotics (Intermediate) - Learn to design custom parts for FDM printing
  • CAD Design (Intermediate) - Create your own robot parts from scratch
  • 3D Printing (Competency Overview) - Explore intermediate and advanced techniques

Build With Your New Skill

Expand Your Capabilities

  • Print custom sensor mounts for new capabilities
  • Design brackets for additional electronics
  • Create custom wheels for different surfaces
  • Build entirely new robot chassis designs

Common Beginner Questions

Q: How do I know if my printer is working correctly?

A: Print a calibration cube and measure it. If dimensions are within 0.2mm of 20mm × 20mm × 20mm, your printer is well-calibrated.

Q: My print failed. What do I do?

A: Identify the failure mode:

  • Failed first layer → Bed leveling issue
  • Warped corners → Bed temperature or adhesion issue
  • Spaghetti mess → Lost adhesion mid-print, clean bed and re-level
  • Layer shifting → Belt tension or mechanical issue
  • Under-extrusion → Temperature, clog, or extruder issue

Q: How long does filament last?

A: 1kg of PLA prints approximately:

  • 50-100 calibration cubes
  • 3-4 complete SimpleBot chassis sets
  • 10-20 smaller parts (brackets, mounts)

Q: Can I leave prints running overnight?

A: Generally yes, but:

  • Watch the first layer before leaving
  • Ensure printer is on stable surface, away from flammable materials
  • Some hobbyists use fire-resistant enclosures for peace of mind
  • Consider cheap WiFi camera to monitor remotely

Q: What if screws/motors don't fit printed parts?

A: Common issue due to printer tolerances:

  • Holes too small → Drill them slightly larger
  • Holes too large → Print at 101-102% scale, or use larger screws
  • Shaft loose → Wrap with tape or print at 99% scale

Q: Do I need supports for SimpleBot parts?

A: SimpleBot parts are designed to print without supports when properly oriented. If your slicer suggests supports, check the part orientation in the slicer.

Troubleshooting Resources

See Also

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