Course outline
Module 1
Module 1: What 3D Printing Is and How It Works
What 3D Printing Is and How It Works
Knowledge check
Q1. What is the basic process by which 3D printing creates an object?
- A. Removing material from a solid block until the desired shape remains
- B. Adding material layer by layer based on a digital 3D model ✓
- C. Casting molten metal into a pre-made mold
- D. Carving a shape by hand with specialized tools
Why: 3D printing, also called additive manufacturing, builds objects by depositing material layer by layer according to a digital 3D model. This is the core principle that distinguishes it from subtractive methods like machining or carving.
Q2. What file format is most commonly used to send a 3D model to a printer?
- A. JPEG
- B. MP3
- C. STL ✓
- D. DOCX
Why: STL (STereoLithography) is the most widely used file format for 3D printing. It represents an object's surface as a mesh of triangles, which the slicing software then converts into printing instructions.
Q3. What is the role of slicing software in 3D printing?
- A. It cuts the physical printed object into smaller pieces for shipping
- B. It converts a 3D model into thin horizontal layers and generates the printer's movement instructions ✓
- C. It measures the temperature of the print bed during printing
- D. It converts the printed object into a digital file for storage
Why: Slicing software divides the 3D model into many thin horizontal layers and produces G-code, the set of instructions that tells the printer where to move, how fast, and how much material to extrude for each layer.
Q4. Which 3D printing technology works by melting and extruding a plastic filament through a heated nozzle?
- A. Stereolithography (SLA)
- B. Fused Deposition Modeling (FDM) ✓
- C. Selective Laser Sintering (SLS)
- D. Binder Jetting
Why: Fused Deposition Modeling (FDM), also called Fused Filament Fabrication (FFF), melts thermoplastic filament and extrudes it through a nozzle layer by layer. It is the most common and affordable consumer 3D printing method.
Q5. Why do many 3D printed objects need support structures during printing?
- A. To make the print cool down faster
- B. To hold up overhanging parts that would otherwise sag or collapse in mid-air ✓
- C. To give the printer's motors something to grip
- D. To increase the weight of the finished object
Why: When a model has overhangs, such as a bridge or an angled surface extending beyond the layer below, the newly deposited material has nothing underneath to rest on. Support structures provide temporary scaffolding that is removed after printing.
Module 2
Module 2: Common 3D Printing Technologies
Common 3D Printing Technologies
Knowledge check
Q1. Which 3D printing technology works by extruding melted thermoplastic filament layer by layer?
- A. Stereolithography (SLA)
- B. Fused Deposition Modeling (FDM) ✓
- C. Selective Laser Sintering (SLS)
- D. Binder Jetting
Why: Fused Deposition Modeling (FDM), also called Fused Filament Fabrication (FFF), heats thermoplastic filament until it melts, then extrudes it through a nozzle to build the object one layer at a time. It is the most common technology in desktop 3D printers.
Q2. What is the main material form used in stereolithography (SLA) printing?
- A. Plastic filament spools
- B. Metal powder
- C. Liquid photopolymer resin ✓
- D. Sheets of paper
Why: SLA printers use liquid photopolymer resin that hardens when exposed to ultraviolet light. A laser or projector cures the resin layer by layer, which allows very fine detail and smooth surfaces.
Q3. Which technology uses a laser to fuse powdered material such as nylon or metal particles into solid layers?
- A. Fused Deposition Modeling (FDM)
- B. Stereolithography (SLA)
- C. Selective Laser Sintering (SLS) ✓
- D. Material Jetting
Why: Selective Laser Sintering (SLS) uses a high-powered laser to selectively fuse particles of powdered material. Unfused powder supports the part during printing, so SLS does not usually need separate support structures.
Q4. What is a key advantage of FDM printing for beginners?
- A. It produces the finest surface detail of any technology
- B. It requires no heating of materials
- C. Printers and materials are relatively affordable and easy to operate ✓
- D. It can only print in metal
Why: FDM printers are generally low-cost, widely available, and simple to set up and operate, which makes them the usual starting point for hobbyists and students. Their surface detail is typically coarser than SLA, and they rely on heating thermoplastics rather than avoiding heat.
Q5. In which technology is a liquid binder selectively deposited onto a powder bed to bind particles together layer by layer?
- A. Binder Jetting ✓
- B. Fused Deposition Modeling (FDM)
- C. Digital Light Processing (DLP)
- D. Selective Laser Sintering (SLS)
Why: Binder Jetting deposits a liquid binding agent onto thin layers of powder, such as sand, ceramic, or metal, gluing the particles together where needed. The unbound powder is removed afterward, and the part is often sintered to strengthen it.
Module 3
Module 3: Materials and How to Choose Them
Materials and How to Choose Them
Knowledge check
Q1. Which 3D printing material is most commonly recommended for beginners because it is easy to print and biodegradable?
- A. ABS
- B. PLA ✓
- C. Nylon
- D. Polycarbonate
Why: PLA (polylactic acid) is made from renewable resources like cornstarch or sugarcane, prints at relatively low temperatures, and rarely warps, making it the most beginner-friendly filament.
Q2. What is a key disadvantage of ABS compared to PLA?
- A. It is too brittle to use for functional parts
- B. It emits fumes and is prone to warping without an enclosure ✓
- C. It cannot be painted or sanded
- D. It dissolves in water
Why: ABS requires higher printing temperatures and a heated bed, and it releases styrene fumes. It also shrinks as it cools, which causes warping, so an enclosure and good ventilation are recommended.
Q3. Which material is best suited for printing flexible parts such as phone cases or gaskets?
- A. PLA
- B. PETG
- C. TPU ✓
- D. PVA
Why: TPU (thermoplastic polyurethane) is a flexible elastomer that bends and stretches without breaking, making it ideal for phone cases, grips, and gaskets.
Q4. What does PETG offer that PLA generally does not?
- A. Better heat resistance and impact toughness ✓
- B. Compostability in home gardens
- C. Lower printing temperature than PLA
- D. Transparency in every color
Why: PETG combines ease of printing with better heat resistance and impact strength than PLA, and it is less brittle, which makes it a popular middle-ground material.
Q5. Why is PVA sometimes used in 3D printing?
- A. It is a strong structural material for load-bearing parts
- B. It is a water-soluble support material for complex geometries ✓
- C. It is the cheapest filament available
- D. It glows under UV light
Why: PVA dissolves in water, so it can be printed as support structures for overhangs and internal cavities, then washed away without damaging the main print.
Module 4
Module 4: Designing Models for Printing
Designing Models for Printing
Knowledge check
Q1. Which file format is most commonly used to send 3D models to a slicer for printing?
- A. DOCX
- B. STL ✓
- C. MP3
- D. PDF
Why: STL (stereolithography) is the most widely supported format for 3D printing. It describes the surface of a model as a mesh of triangles, which slicer software can convert into printable layers.
Q2. What does a wall thickness that is too thin most likely cause in a printed part?
- A. The part will print faster
- B. The part may be fragile or fail to print properly
- C. The part will become waterproof
- D. The part will automatically gain color
Q3. Why do designers often add a chamfer or fillet to the bottom edges of a model?
- A. To reduce the file size of the model
- B. To make the model heavier
- C. To reduce overhangs and improve how the first layers adhere to the build plate
- D. To change the color of the print
Q4. What is the purpose of adding clearance between mating parts in a design meant for printing?
- A. To make the parts glow in the dark
- B. To allow for printer tolerances so parts fit together after printing
- C. To increase the number of supports needed
- D. To lower the print temperature
Q5. Which of the following is a common guideline for designing overhangs that print without support?
- A. Overhangs should be no steeper than about 45 degrees from vertical
- B. Overhangs should always be exactly horizontal
- C. Overhangs should be as steep as possible to save material
- D. Overhangs should only be placed on the top face of the model
Module 5
Module 5: Preparing Files and Slicer Settings
Preparing Files and Slicer Settings
Knowledge check
Q1. What file format is most commonly used to send 3D model geometry to a slicer before slicing?
- A. DOCX
- B. STL ✓
- C. MP3
- D. PDF
Why: STL (stereolithography) is the most widely used format for 3D printing because it describes the surface geometry of a model as a mesh of triangles, which slicers can convert into printable layers.
Q2. What does the slicer do with a 3D model before printing?
- A. It paints the model with colors for display
- B. It converts the model into a series of thin horizontal layers and generates machine instructions (G-code) ✓
- C. It compresses the model to reduce file size only
- D. It sends the model directly to the printer's firmware without changes
Why: A slicer cuts the 3D model into thin horizontal layers and produces G-code, the set of commands that tells the printer where to move, how fast, and how much material to extrude for each layer.
Q3. What does layer height control in slicer settings?
- A. The total height of the printed object
- B. The thickness of each horizontal layer printed, which affects surface detail and print time ✓
- C. The temperature of the print bed
- D. The speed of the cooling fan
Why: Layer height sets how thick each printed layer is. Smaller layers give finer surface detail but increase print time, while larger layers print faster with more visible layer lines.
Q4. What is the purpose of infill percentage in slicer settings?
- A. It determines the color of the internal structure
- B. It sets how much of the interior of the print is filled with internal support pattern, affecting strength and material use ✓
- C. It controls how many copies of the model are printed
- D. It adjusts the brightness of the printer's display
Why: Infill percentage controls how dense the internal structure of a print is. Higher infill makes parts stronger and heavier but uses more material and time, while lower infill saves both.
Q5. Why might you need to check a model's mesh for errors before slicing?
- A. Mesh errors only affect the color of the print
- B. Non-manifold edges or holes can cause the slicer to fail or produce incorrect layers, so repairing them helps ensure a successful print ✓
- C. Mesh errors automatically make the printer faster
- D. Slicers cannot read any model that has been checked
Why: Models with holes, inverted normals, or non-manifold geometry can confuse the slicer, leading to failed slices or prints with gaps. Checking and repairing the mesh before slicing prevents these problems.
Module 6
Module 6: Printer Setup, Calibration, and Maintenance
Printer Setup, Calibration, and Maintenance
Knowledge check
Q1. What is the main purpose of bed leveling on a 3D printer?
- A. To make the printer run quieter during operation
- B. To ensure the nozzle is a consistent distance from the build plate across its entire surface ✓
- C. To increase the maximum print speed of the printer
- D. To reduce the amount of filament used in each print
Why: Bed leveling ensures the nozzle sits at a consistent height above the build plate everywhere, so the first layer adheres properly and extrudes evenly. An unlevel bed can cause prints to fail to stick in some areas or to be squished too thin in others.
Q2. What does E-steps calibration adjust on a 3D printer?
- A. The speed of the cooling fans
- B. The temperature of the hotend
- C. The amount of filament the extruder pushes for a given command ✓
- D. The height of the Z-axis endstop
Why: E-steps (extruder steps per millimeter) calibration ensures that when the printer commands a specific length of filament to be extruded, the correct amount is actually pushed through. Incorrect E-steps lead to over- or under-extrusion, affecting print quality and dimensional accuracy.
Q3. Why should you regularly clean the nozzle of your 3D printer?
- A. To prevent the nozzle from overheating
- B. To remove buildup that can cause clogs and inconsistent extrusion ✓
- C. To change the color of the printed object
- D. To increase the printer's Wi-Fi signal strength
Why: Residual filament and debris can accumulate on or inside the nozzle, leading to partial clogs, uneven flow, and poor print quality. Regular cleaning helps maintain consistent extrusion and prevents more serious blockages.
Q4. What is a common sign that your printer's belts need tightening or replacing?
- A. The print bed turns a different color
- B. Layer shifting or ghosting patterns appear in printed parts ✓
- C. The filament spool becomes harder to load
- D. The display screen dims over time
Why: Loose or worn belts can cause the axes to move inaccurately, resulting in layer shifts (where layers are offset from one another) or ghosting (ringing echoes near features). Checking belt tension is a routine maintenance step for this reason.
Q5. Which of the following is a recommended practice when first setting up a new 3D printer?
- A. Skipping calibration because new printers are factory perfect
- B. Running a test print and adjusting settings based on the results ✓
- C. Printing at the highest possible speed right away
- D. Removing the build plate so the printer can cool faster
Why: Even new printers benefit from calibration, since shipping, assembly, and environmental factors can affect accuracy. Running a test print, such as a calibration cube or first-layer test, reveals issues that can then be corrected through leveling, offsets, or steps adjustments.
Module 7
Module 7: Troubleshooting Prints and Post-Processing
Troubleshooting Prints and Post-Processing
Knowledge check
Q1. What is 'stringing' in 3D printing?
- A. Thin wisps of plastic left between separate parts of a print where the nozzle travelled without extruding ✓
- B. Layers that fail to bond to each other, causing the print to split apart
- C. A rough, bumpy texture on the outer walls caused by excessive cooling fan speed
- D. Filament that jams inside the extruder gear due to moisture absorption
Why: Stringing occurs when molten filament oozes from the nozzle during non-printing moves, leaving thin strands between features. It is commonly reduced by lowering nozzle temperature, increasing retraction distance or speed, and drying the filament.
Q2. A print shows visible ripples or waves on its vertical walls. Which fix is most likely to help?
- A. Increase the print bed temperature to 150 degrees Celsius
- B. Reduce the printing speed to the minimum possible
- C. Check for loose belts or frame components and reduce acceleration settings ✓
- D. Switch to a larger nozzle diameter of 1.0 mm
Why: Ringing or ripples on walls are typically caused by mechanical vibration, often from loose belts, a wobbly frame, or high acceleration. Tightening hardware and lowering acceleration reduces these vibrations.
Q3. A print is lifting off the build plate at the corners during printing. What is the most appropriate solution?
- A. Add a brim or raft and improve bed adhesion through cleaning or leveling ✓
- B. Turn the cooling fan to maximum speed for the entire print
- C. Increase the layer height to make each layer heavier
- D. Lower the nozzle temperature by 50 degrees
Why: Warping and corner lifting happen when the part contracts as it cools and pulls free from the bed. Adding a brim or raft increases contact area, and proper bed leveling and cleaning improve adhesion.
Q4. Which post-processing technique is commonly used to smooth the layer lines on a printed PLA part?
- A. Sanding with progressively finer grit sandpaper, followed by priming and painting ✓
- B. Placing the part in a freezer for several hours
- C. Soaking the part in acetone to dissolve the surface
- D. Exposing the part to ultraviolet light for 24 hours
Why: Sanding from coarse to fine grit removes layer lines mechanically, and a primer or filler can then be applied before painting. Acetone smoothing works for ABS, not PLA, which is why it is not the best choice here.
Q5. Your print has gaps in the top surface and you can see the infill pattern through it. What setting is most likely too low?
- A. Number of top solid layers ✓
- B. Print bed temperature
- C. Retraction distance
- D. Fan speed percentage
Why: Gaps or visible infill on the top surface usually mean there are too few top solid layers to fully cover the infill. Increasing the top layer count, typically to 4 to 6 layers, solves this problem.