3D Printing 101

Welcome to the fascinating world of 3D printing! This guide will introduce you to the basics of 3D printing and help you get started with this amazing hobby.

What is 3D Printing?

3D printing, also known as additive manufacturing, is a process of creating three-dimensional objects from a digital file. Instead of removing material, 3D printing adds material layer by layer to build an object.

FDM works by using thermoplastic filament, which is basically a cord of plastic that can be melted, selectively deposited, and cooled. This is repeated, layer by layer, until an entire model is formed.

This technology was created by people who wanted to rapidly prototype parts. Even today, rapid prototype production is one of the biggest benefits of FDM and 3D printing in general. Not surprisingly, 3D printing has also become a potent manufacturing solution.

Before we proceed with the details of how FDM works, there's one more thing worth mentioning. In case you've already done some research on 3D printing, you may have noticed that some sources use the term "FFF", which stands for "fused filament fabrication", instead of "FDM". That's because the term FDM was originally trademarked by Stratasys, and the other abbreviation is a more general term. Remember, it's the same technology, only the names are different. Today, most people use "FDM".

Types of 3D Printing

There are several types of 3D printing methods, but the most popular ones are:

FDM (Fused Deposition Modeling): Uses a spool of filament which is heated and extruded layer by layer.
MSLA (Masked Stereolithography): The most common consumer resin printing technology. Uses an LCD screen to mask a UV light source, curing an entire layer of resin at once. This is what most affordable resin printers use today (e.g., Elegoo Mars, Anycubic Photon series).
SLA (Stereolithography): The original resin printing method. Uses a UV laser to trace and cure each layer point by point. Generally higher precision than MSLA but also more expensive. Common in professional and dental applications.
SLS (Selective Laser Sintering): Uses powder and a laser to create objects. Mostly industrial, though some desktop options have emerged.

Types of 3D Printers

Cartesian: also known as i3 or bed-slingers, these were the most prolific for a while, but other technologies are starting to take over. Here, the print head moves along the x and z axis, and the bed moves along the y axis. These have proven to be reliable but slow.
CoreXY: These machines are known for speed and can be seen on higher-end machines such as the Bambu Lab machines and the Prusa Core One and Prusa XL. With these machines, the z axis (bed) moves up and down and the print head (also known as tool head), moves along the x and y axis via belts driven by motors typically in the back of the gantry. This has the added benefit of a lighter print head and allowing for faster print speeds at the cost of complexity.
And others: See 3D Printer Hardware for more.

Getting Started

1. Choosing a Printer

Depending on your budget and requirements, there are several great printers available for beginners, such as:

Bambu Lab A1 Mini - A fantastic entry point in 2025/2026. CoreXY, fast, beginner-friendly, and works great out of the box with minimal tinkering. Multi-color printing is available as an add-on (AMS Lite).
Creality K1C - Creality's capable CoreXY offering. Good speed and quality at a competitive price, with solid community support.
Creality Ender 3 V3 - The classic entry-level Cartesian machine in its latest iteration. A great budget option if you don't mind a slightly slower pace.
Prusa MK4 / MK4S - High-end bed-slingers known for legendary reliability and quality... and price tag. The MK4S is the current top-of-the-line model. (Note: the older MK3S+ is end-of-life.)
Bambu Lab X1C / P1S - The performance flagships from Bambu. These CoreXY machines challenged the status quo with their speedy prints without sacrificing quality. They achieve this using technology not typically seen on other printers, such as LIDAR and dual bed leveling. The P1S adds a full enclosure, making it great for engineering materials like ABS and ASA.
Anycubic Kobra Series - budget-friendly machines with good performance and features for the price, with some drawbacks such as a less robust frame and less reliable bed leveling.
Elegoo Mars Series (Resin) - For those interested in resin printing, the Mars series offers excellent quality and affordability for beginners.
Anycubic Photon Series (Resin) - Another great option for resin printing, known for its reliability and ease of use.

2. Selecting Filament/Resin

PLA: Most common filament, "biodegradable", and easy to print with.
While it is biodegradable, it will take many many years to decompose
PETG: Arguably now more popular than ABS for functional parts. Tougher and more heat-resistant than PLA, easy to print, and doesn't require an enclosure or emit harsh fumes. A great next step after PLA.
ABS: Durable but requires a heated bed. Emits toxic fumes and is sensitive to temperature changes and drafts, so you must use an enclosure and either have filtration or be in a well-ventilated area.
ASA: Think of ASA as the outdoor-ready version of ABS. Similar strength and heat resistance, but significantly better UV and weather resistance. Great for anything destined to live outside. Like ABS, it benefits from an enclosure.
TPU: Flexible filament. Can be tricky to print. Typically used on direct drive systems, where the extruder sits on the tool head.
Resin: For MSLA/SLA printers. Toxic, but most machines on the market now have built-in filtration systems. Requires extensive post-processing consisting of:
Breaking away supports
Washing/bath in alcohol
Curing under UV light
Models show no visible layer lines, and details are typically much sharper than FDM
However, resin prints are generally more brittle than FDM prints and not suitable for functional parts. They are perfect for miniatures, jewelry, and other decorative items.

3. Design and Slicing

Design

Design your model using software like Tinkercad, Fusion 360, OnShape, FreeCAD, or Blender.
Or download models from sites such as Thingiverse, Thangs.com, Printables.com, MakerWorld (Bambu's model platform, which has grown rapidly in popularity), and others.

FDM Slicing

Slicing is where most of the real decision-making happens. A slicer takes your 3D model and converts it into G-code — the layer-by-layer instructions your printer executes. The choices you make here directly determine print success, part strength, surface quality, and how long the print takes. Slicers like Cura, PrusaSlicer, OrcaSlicer, and Bambu Studio all work on the same principles; some vendors ship their own slicers, but these are typically forks of the open-source tools listed above.

Once sliced, export the file to your printer via the network, cloud, or an SD card inserted into the printer.

Object Orientation

The single most impactful decision you make in the slicer is how you orient the model on the build plate. FDM prints are anisotropic — they are strongest along the X/Y plane (within a layer) and weakest along the Z axis (between layers), because inter-layer bonding is never as strong as the material itself.

Orient flat, wide surfaces facing down to maximize bed contact, minimize supports, and improve bottom surface quality.
Orient the weakest or most stress-bearing cross-section of a functional part perpendicular to the Z axis (i.e., parallel to the layer lines) so the layers run with the load rather than across it. A hook printed vertically will snap far more easily than the same hook printed on its side.
Tall, narrow parts are prone to tipping or vibrating mid-print — consider laying them on their side if the strength trade-off in that axis is acceptable.
Avoid orienting large overhangs beyond roughly 45° facing up without supports, but solve the problem through orientation before reaching for supports.

Supports

Supports are temporary structures printed beneath overhangs and bridging areas that would otherwise sag or fail. They are removed after the print.

FDM can bridge horizontal gaps between two supported points without supports up to approximately 50–60 mm depending on material and cooling. Overhangs up to ~45° from vertical typically print cleanly without supports.
Normal/linear supports (grid or lines pattern) are the default — straightforward to generate, but can fuse to the model surface and leave rough marks. Tree supports branch up from the build plate to contact only the points that need them — they use less material, are generally easier to remove, and leave a better surface finish underneath.
Interface layers sit at the very top of a support where it contacts the model. A denser or differently-patterned interface dramatically improves surface quality on the underside of the model and makes removal easier. On multi-material printers, printing the interface in a dissolvable filament (PVA, BVOH) eliminates manual removal entirely.
Every support adds print time, material, and post-processing effort. Minimize them through smart orientation first, then add only what is necessary.
Support Z distance is the gap between the top of the support and the bottom of the model surface. Too small and the support fuses to the print; too large and the overhang quality suffers. Dialing this in for your specific material and printer is worth the effort.

Walls, Perimeters, and Strength

Walls (also called perimeters or shells) are the outer layers that define the visible surface and structural skin of the print.

More walls equal a stronger part and better surface appearance. For decorative or non-functional prints, 2 walls is typically sufficient. For functional parts, 3–5 walls significantly increases strength, especially in parts that experience lateral stress or impacts.
For very demanding structural applications, going all-wall (0% infill, high wall count) is often stronger than a low wall count with high infill — the continuous perimeters carry loads more efficiently than sparse internal structure.
The Arachne perimeter generator (available in OrcaSlicer, PrusaSlicer, and modern Cura) produces variable-width perimeters that fill narrow gaps more efficiently, improving strength and surface quality on complex geometry.

Infill

Infill is the internal structure printed inside the walls. It determines how solid and heavy the part is, and has a direct impact on strength, material use, and print time.

Infill percentage: 10–15% is typical for decorative prints; 20–40% for general-purpose functional parts; 50–80%+ for high-stress parts. Note that beyond roughly 40%, adding more infill has diminishing returns — adding walls gives better strength per unit of material at that point.
Infill pattern:
Gyroid — isotropic (roughly equal strength in all directions), great for flexible or rubber-like parts and general functional use; looks striking on transparent filaments.
Grid / Lines — fast to print, adequate for decorative and low-stress prints.
Honeycomb / 3D Honeycomb — good strength-to-weight ratio for moderate-load parts.
Lightning — generates the absolute minimum infill needed to support top surfaces. Fastest and least material, for non-structural prints only.
Cubic / Cubic Subdivision — strong in all three axes; a solid choice for functional parts.
Top/bottom layers: the solid layers above and below the infill. More layers produce a better surface finish on the top and bottom faces of the print. 4–6 layers is a good target for smooth, closed surfaces.

Strength vs. Aesthetics: Practical Settings

For aesthetics and display models: prioritize smooth surfaces (more top/bottom layers, smaller layer height, variable layer height on curved surfaces), tree supports for clean undersides, lower infill, and consider enabling ironing on top surfaces for a polished flat finish.
For functional and structural parts: prioritize walls over infill, orient load paths perpendicular to Z, increase top/bottom layers, and consider annealing PLA+ or switching to PETG, ASA, or ABS for heat and impact resistance.
Layer height affects both strength and surface quality. Smaller layers (0.1–0.15 mm) give better surface finish and stronger Z-axis bonds; larger layers (0.25–0.3 mm) print faster with slightly lower Z strength. A common middle ground for most prints is 0.2 mm.

Variable Layer Height

Most modern slicers allow you to assign different layer heights to different vertical regions of a model. Use finer layers on curved or highly detailed sections and larger layers on simple vertical walls — this saves significant print time without sacrificing surface quality where it matters.

Fuzzy Skin

Fuzzy skin is a slicer feature that intentionally roughens the outer surface of a print to create a textured appearance. It obscures layer lines and gives a matte, tactile finish that many people find more appealing than a smooth FDM surface.

Useful for aesthetic models where a perfect surface is less important, parts that benefit from a grippy texture, or hiding minor surface defects.
Not suitable for dimensionally precise parts, functional mating surfaces, or anything requiring accurate outer dimensions — fuzzy skin adds material beyond the model boundary and will affect fit.

Modifiers and Negative Parts

Most advanced slicers (OrcaSlicer, PrusaSlicer, Bambu Studio) allow you to place a 3D volume over part of your model to override slice settings in that region only. This is called a modifier mesh or height range modifier.

Common uses: adding extra infill or walls only in a specific area (e.g., reinforcing around a mounting hole without making the whole part denser), changing layer height in one zone, or applying different support settings to one section of a complex model.
Negative volumes (sometimes called "negative parts"): assigning an intersecting volume as a negative removes material from the model at that intersection — useful for adding clearance holes, channels, or cutouts without modifying the original CAD file.

Scaling Objects

Slicers can scale models freely, but a few caveats are worth knowing:

Wall thickness: scaling a model down may make walls thinner than the nozzle diameter, causing the slicer to omit them or fill them inconsistently. Always preview the sliced result after scaling.
Hole tolerances: holes in FDM prints already tend to print slightly undersized due to material expansion. Scaling changes the absolute hole size, which may require re-drilling or a design tweak to hit a target fit.
Non-uniform scaling: scaling differently in X, Y, and Z distorts geometry and can cause mating parts to no longer fit. When scaling to compensate for dimensional error (e.g., elephant foot, shrinkage), scale uniformly.
Mechanical fits: if a part is designed with specific tolerances (press fits, snap fits), scaling does not preserve those tolerances — the designer's tolerance stack is built for 100% scale.

Resin Slicing

Resin slicers work quite differently from FDM slicers. Instead of generating toolpaths, they slice the model into a sequence of flat images — each image is projected onto the resin surface layer by layer to cure it. The dominant consumer slicer for resin is Chitubox, but Lychee Slicer and others (Formware, PrusaSlicer's SLA mode) are also solid options.

Exposure Settings

Layer exposure time is the most critical variable in resin printing. Too short and layers don't cure fully, resulting in a failed or fragile print. Too long and fine detail is lost through bleed or blooming, and the print may become over-cured and brittle.

Bottom layer exposure is set separately and is much longer than normal layers — this ensures the first few layers bond firmly to the build plate before the rest of the print is supported only by those initial layers.
Each resin formulation has a different optimal exposure time. Always run an exposure calibration print (e.g., an R_E_R_F test, Cali Cat, or AmeraLabs Town) when using a new resin or switching printers. Guessing exposure time wastes resin and often fails.

Orientation and Suction Forces

Orientation in resin printing is more nuanced than in FDM because each layer must physically separate from the FEP film at the bottom of the vat before the next layer can be exposed. Large flat surfaces parallel to the build plate create enormous suction forces during this peel step, frequently causing print failures or FEP damage.

Tilt parts 30–45° to break up flat cross-sections into smaller progressive contact areas, reducing peel forces layer by layer and significantly improving print success rates.
Hollow tall parts and add drain holes at low points to prevent liquid resin pooling inside the model during printing.

Hollowing

Solid resin prints are heavy, slow to cure internally (the heat from mass curing can warp the print), expensive in resin use, and prone to cracking over time as internal stresses build up. Hollowing is almost always worthwhile for anything larger than a few centimeters.

Hollowing the model in the slicer (Chitubox has a built-in hollow function) dramatically reduces resin use and print time. Leave walls of 2–4 mm depending on the model's size and required strength.
Always add drain holes at the lowest points of the hollow cavity so uncured liquid resin can drain out during and after printing. Trapped liquid resin will continue to cure slowly over time and will eventually expand, cracking the print from the inside.

Supports in Resin

Resin supports are thin pillars that connect the build plate to the underside of the model. Unlike FDM, supports in resin printing are almost always required because the model is printed inverted — hanging from the build plate — and unsupported geometry simply peels away.

Chitubox's auto-support function works well as a starting point but may miss critical contact points or place supports on visible surfaces. Always manually review auto-generated supports, add supports on undersides, tips, and isolated islands, and remove any placed on surfaces you want clean.
Use light supports for fine details and thin areas; medium and heavy supports for large flat sections and primary structural attachment points.
Orient the model to place support contact points on non-visible surfaces wherever possible — support removal always leaves a small nub or mark, even with careful cleanup.

Anti-aliasing and Layer Smoothing

Resin slicers can apply anti-aliasing to the edges of each projected layer image to reduce the visible stair-stepping between layers. Enable this for display models and miniatures — at 0.05 mm layer heights it makes a noticeable difference in how smooth curved surfaces appear on the final print.

4. Printing and Post-processing

FDM Post-Processing

Print your object!
Clean up the model by removing supports and sanding if needed.
Sanding: Start with a coarser grit (120–220) to remove layer lines and support marks, then work up to finer grits (400–800+) for a smooth finish. Wet sanding gives the best results on plastic and reduces dust.
Priming and painting: A sandable filler primer fills remaining surface texture before painting. Standard acrylic or enamel paints work well on FDM prints; spray paint gives the most even coverage and avoids brush marks.
Acetone smoothing (ABS only): ABS can be vapor-smoothed using acetone to dissolve and re-flow the surface, producing a near-injection-molded finish. This requires careful safety precautions — acetone is highly flammable and the vapors are harmful. Do this outdoors or with excellent ventilation, away from any ignition sources.
Heat set inserts: Brass threaded inserts can be pressed into printed holes using a soldering iron, providing durable metal threads in plastic parts. This is far superior to threading directly into plastic for any part that will be assembled and disassembled more than a few times.

Resin Post-Processing

Resin prints require several post-processing steps before they are safe to handle freely and fully hardened. This is not optional — skipping steps results in prints that are tacky, weak, or structurally compromised over time.

Washing

Fresh prints are coated in uncured liquid resin, which is toxic and must be removed before UV curing.

The most common washing method is isopropyl alcohol (IPA, 90%+) or a dedicated wash solution. Elegoo Water Washable resins use plain water; most standard and engineering resins require IPA or a dedicated solvent.
Most users use a wash & cure station (a spinning basket in a sealed container that agitates the solvent around the print) or a two-container system: a first bath to remove the bulk of the liquid resin, followed by a cleaner second bath for a final rinse.
Wash time is typically 2–5 minutes in agitated IPA. Over-washing — especially water-washable resins — softens and weakens the print. Set a timer.
After washing, shake off excess liquid and let the print air-dry completely before curing. IPA trapped in crevices or hollow cavities inhibits UV curing and leaves tacky spots.

Curing

UV light fully polymerizes (hardens) the resin after washing. Under-cured prints are soft, tacky, and fragile. Over-cured prints become overly stiff, may yellow, and can become more brittle than properly cured parts.

Use a UV curing station (e.g., Elegoo Mercury Plus, Anycubic Wash & Cure) with a rotating turntable for even, consistent exposure. Direct sunlight works in a pinch but is slower and less controllable.
Cure times vary by resin — standard resins typically need 2–6 minutes under a UV station; water-washable and engineering resins may need longer. Always check the resin manufacturer's recommendation as a starting point.
Where possible, cure with supports still attached to protect delicate features during the curing process, then remove supports after the initial cure while the material is still very slightly flexible.

Support Removal

Remove supports after a brief initial cure, when the print is mostly hardened but still has a tiny amount of flex — fully cured supports are brittle and snap suddenly, which can take part of the model with them.
Use flush cutters, dental picks, or your fingers on light supports. Work carefully and slowly on visible surfaces to minimize marking.
Support nubs left on the surface can be sanded smooth with fine-grit wet sandpaper (400–800).

Safety During Post-Processing

Wear nitrile gloves throughout the entire process — uncured resin is a skin sensitizer, and repeated unprotected exposure can cause lasting allergic reactions that make continued work with resin impossible.
Work in a well-ventilated area. IPA vapors and resin fumes are harmful in enclosed spaces.
Do not pour resin-contaminated IPA down the drain. Cure the used wash solution by spreading it in a shallow tray in direct sunlight to harden the suspended resin particles, then filter out the solids for disposal as solid waste, and dispose of the remaining IPA appropriately.
Keep all resin products, wash solutions, and curing stations away from children and pets.

Common Issues and Solutions

Warping: Caused by uneven cooling. Use a heated bed or enclose the printer.
Clogging: Regularly clean the nozzle.
Poor Adhesion: Clean the bed, use adhesive agents, or adjust bed leveling.
Stringing: Thin wispy threads of plastic between parts of a print. Usually caused by the nozzle oozing while moving. Tuning retraction settings in your slicer and lowering print temperature are the main fixes.
Layer Delamination / Poor Layer Adhesion: Layers separating or not bonding properly. Common causes include printing too fast, too cool, or with damp filament. Try increasing print temperature, reducing speed, or drying your filament before printing.

Safety Tips

Ensure good ventilation when printing, especially with ABS and ASA.
Never leave a printer unattended.
Keep printers away from flammable materials.
When working with resin, always wear nitrile gloves and work in a well-ventilated area. Uncured resin is a skin irritant and should not be washed down the drain.

Resources

All3DP has an amazing 3D printing 101 article here
Model Libraries: Printables, MakerWorld, Thingiverse, and Thangs
Forums: Websites like Reddit's r/3Dprinting and the RepRap community.
Tutorials: YouTube channels like Maker's Muse, Teaching Tech, and Thomas Sanladerer.

Happy Printing!