Glossary of 3D Printing Terms (Additive Manufacturing A-Z)

0-9: 3D Printing Basics

3D Model

A 3D model is a digital representation of a three-dimensional object, typically created with CAD software or 3D scanning. It defines the geometry of the object (often as a mesh of polygons) and can be exported to formats like STL or OBJ for 3D printing. A printable 3D model should be “watertight” (manifold), meaning it has no holes or internal gaps, so that the slicer can interpret it as a solid for printing.

3D Printer

A 3D printer is the machine that performs the 3D printing process, building a solid object layer by layer from a digital design. There are many types of 3D printers (FDM, SLA, SLS, etc.), but all consist of a build platform and some form of print head or energy source that deposits or solidifies material in layers. 3D printers can range from small desktop units to large industrial systems, capable of creating complex geometries that traditional manufacturing might not easily achieve.

3D Printing

3D printing is the process of creating a physical object from a digital model by adding material one layer at a time (hence additive manufacturing). Unlike subtractive manufacturing (where material is cut or milled away, as in CNC machining), 3D printing builds objects up, which enables complex shapes, reduces waste, and allows rapid prototyping ( An A to Z Guide of 3D Printing Terminology | Protolabs ). There are various 3D printing technologies (FDM, SLA, SLS, etc.), but all involve layering material under computer control to form the final part.

A

ABS (Acrylonitrile Butadiene Styrene)

ABS is a common thermoplastic polymer used in FDM 3D printing. It is known for its toughness, higher temperature resistance, and improved ductility compared to PLA ( 3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). ABS is a petroleum-based plastic, often used for functional prototypes and end-use parts because of its strength. However, ABS can warp as it cools, so printing it usually requires a heated bed and ideally an enclosed printer to maintain temperature. (ABS can be smoothed with acetone vapor – see Acetone. )

Acetone

Acetone is a solvent with two main uses in FDM 3D printing (for ABS plastic only). First, acetone vapor can be used to smooth ABS prints by slightly melting their outer surface (an “acetone vapor bath”), eliminating layer lines for a glossy finish (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Second, acetone can be mixed with ABS scraps to create an “ABS juice” or slurry that is applied to the build plate to help ABS prints stick and prevent warping (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Safety note: Acetone is flammable and should be used with proper ventilation and care.

Additive Manufacturing (AM)

Additive manufacturing , also known as 3D printing , refers to any process that creates three-dimensional objects by adding material layer by layer ( An A to Z Guide of 3D Printing Terminology | Protolabs ). As the name suggests, it adds material (in successive layers) rather than removing it (contrast with subtractive manufacturing ). There are many additive manufacturing technologies – including stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), and more – but all share the layer-by-layer building principle. Additive manufacturing offers great flexibility in design, the ability to produce complex geometries, and often faster turnaround for prototypes or custom parts ( An A to Z Guide of 3D Printing Terminology | Protolabs).

Additive vs. Subtractive Manufacturing

Subtractive manufacturing refers to traditional processes that create objects by removing material from a solid block (for example, CNC milling, turning, or drilling). Additive manufacturing (3D printing) does the opposite: it builds the object by adding material layer by layer ( An A to Z Guide of 3D Printing Terminology | Protolabs). The key difference is that subtractive methods tend to waste material (as chips or cut-away pieces) and may struggle with very complex shapes, whereas additive methods can create complex internal structures with minimal waste. However, subtractive processes like CNC machining are often faster for simple parts and can yield very high precision or smooth surfaces without post-processing. In practice, manufacturers choose additive vs. subtractive based on the part’s design requirements.

Axis (X, Y, Z Axes)

3D printers operate on the X, Y, and Z axes , which correspond to width (X, left-right), depth (Y, front-back), and height (Z, up-down) in a Cartesian coordinate system. Most printers have motors and rails for each axis that precisely position the print head or build plate according to the 3D model’s coordinates (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Proper calibration of movements along all axes is critical for print accuracy. Some printers (Cartesian style) move the print head in X and Y and the bed in Z, while others (like delta printers) have a different motion system but still ultimately control movement in X, Y, Z directions.

B

Binder Jetting

Binder jetting is an additive manufacturing technology where a liquid binder is selectively deposited onto thin layers of powder (such as metal, sand, or ceramic powder) to bind those areas together (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). A binder jet printer spreads a layer of powder, then an inkjet print head sprays binder adhesive where the part cross-section is. Layer by layer, the powder is glued into the shape of the object. After printing, the “green” (uncured) part is typically weak and is cured or sintered in an oven to fully solidify. The unbound powder supports the part during printing and is removed and recycled afterward. Binder jetting can produce complex geometries without support structures, and is used for anything from metal parts (after sintering) to full-color sandstone or silica objects (when using colored binder).

Bioprinting

Bioprinting is a specialized form of 3D printing that fabricates tissue-like structures using living cells and biomaterials (often called “bio-ink”). It is an additive, layer-by-layer process for creating artificial tissues or potentially organs (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Instead of plastic or resin, bioprinters dispense cell-laden hydrogels or other biocompatible materials, which may be solidified by light or chemical processes. The goal is to produce functional biological tissue – for example, skin grafts, cartilage, or organ scaffolds – that can be used in medical research or therapeutic transplants. Bioprinting is a rapidly evolving field at the intersection of engineering, biology, and medicine.

Brim

A brim is a type of adhesion helper in FDM printing – essentially extra material printed around the base of a part on the first layer. It’s similar to a skirt, but a brim touches and is attached to the first layer of the object (like the brim of a hat around its base). The brim increases the surface area of the print’s first layer, helping it stick more firmly to the bed and thus avoiding warping at the edges (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). After printing, the brim (which is just a few perimeter outlines) can be peeled off. Brims are commonly used for materials prone to warping (ABS, ABS blends) or for small footprints that need extra adhesion.

Build Plate (Print Bed)

The build plate (or print bed / build platform) is the flat surface on which the 3D printer builds the object. In FDM printers, this is the plate where the extruded filament is deposited layer by layer ( 3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). In resin printers (SLA/DLP), the build plate is the platform that dips into the resin vat and to which the solidified resin layers stick as the object is pulled upward ( 3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Build plates are often heated (heated bed) for FDM printing; a heated bed (typically 50–110 °C, depending on material) improves first-layer adhesion and prevents warping by keeping the bottom layer warm until the print is done (An A to Z Guide of 3D Printing Terminology | Protolabs). Ensuring the build plate is level and at the correct nozzle distance (see bed leveling under “L”) is critical for print success. Common build plate surfaces include glass, aluminum, or flexible steel sheets, often coated with tape, PEI, or other adhesives to help parts stick but still release after cooling.

C

CAD (Computer-Aided Design)

CAD refers to the use of computer software to create and modify design models. In 3D printing, CAD software is used to design the 3D model of an object before it’s printed. Users can draw precise 2D sketches and then extrude or revolve them into 3D shapes, or directly model 3D geometries. The resulting CAD model can be exported as an STL or other file format for slicing. Common CAD programs used in 3D printing include SolidWorks, Autodesk Fusion 360, AutoCAD, Blender (for artistic modeling), and many more. Mastering CAD is important for engineers and designers to fully leverage additive manufacturing, as it allows for creating complex custom parts that can then be printed.

Cartesian 3D Printer

A Cartesian printer is the most common design for 3D printers, named after the Cartesian coordinate system it uses for movement. These printers have three linear axes (X, Y, Z) with motors and rails guiding the print head and/or bed along each axis (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). For example, a typical Cartesian FDM printer moves the print head in the X and Y directions, while the build plate moves up and down (Z axis) as each layer is completed. Cartesian printers are relatively straightforward to understand and calibrate. Examples include the Prusa i3, Ultimaker, Creality Ender, and most DIY 3D printer kits – all of which move in straight lines along X, Y, Z. (By contrast, see Delta printer under “D” for an alternative motion system.)

Clogging (Nozzle Jam)

Clogging, or a filament jam, occurs when the filament can’t flow through the printer’s nozzle properly, causing extrusion to stop. This is a common FDM troubleshooting issue. A clog can be caused by hardened filament stuck in the nozzle, debris or burnt residue blocking the orifice, using incorrect temperatures (leading to partial solidification), or even filament quality issues. When a jam happens, the printer’s extruder gear may grind the filament or the filament might buckle, resulting in no material being deposited. To fix a clog, one often needs to purge the hotend (for example, perform a “cold pull” to yank out contaminants) or physically clear the nozzle. Preventive measures include keeping filament dry (brittle, moisture-laden filament can cause jams) and not running the hotend at too low a temperature for the filament. Regular maintenance of the nozzle can help avoid jams (An A to Z Guide of 3D Printing Terminology | Protolabs).

CNC Machining (Computer Numerical Control)

CNC machining is a subtractive manufacturing process where computer-controlled tools (mills, lathes, routers, etc.) remove material from a solid block (metal, plastic, wood) to create a part. We mention CNC here because it’s often compared to 3D printing. In CNC, a digital design is translated into G-code instructions that drive cutting tools along X, Y, Z (and sometimes additional rotary axes) to carve out the object. CNC machining generally offers very high precision and better material properties (since parts are made from solid stock), but it’s less efficient for very complex geometries or internal features that would require multiple tool setups. Many manufacturing workflows combine CNC and 3D printing: for example, 3D print a prototype (additive) and later CNC machine the final part from metal (subtractive). CNC is a well-established technology used for everything from aerospace components to custom enclosures, and understanding its strengths relative to additive manufacturing is useful for choosing the right production method.

Curing

Curing is a term mostly used in resin 3D printing (SLA/DLP). It refers to the process of hardening a liquid photopolymer resin by exposing it to ultraviolet (UV) light. In an SLA or DLP printer, each layer is cured in situ by a laser or projector light. After printing, the part is often only partially cured (it may be tacky or not at full strength), so it is typically post-cured by placing it under a UV lamp or sunlight to fully solidify the resin. Proper curing gives the printed part its final mechanical properties and stability. Essentially, curing is what turns the liquid resin into solid plastic – a chemical reaction initiated by light that cross-links the polymer chains (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). (In FDM, “curing” can also refer to the cooling/solidifying of extruded thermoplastic, but that’s more often just called cooling or solidification; curing is primarily used for photopolymer resins and some specialty materials like UV-curable binders or inks.)

D

Delta Printer

A Delta printer is a type of FDM 3D printer design characterized by three vertical columns (forming a triangle footprint) and three arms that move the print head. Unlike Cartesian printers, a delta printer’s print head is suspended by three articulating arms that slide up and down on the vertical rails (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). By moving these arms in concert, the print head can be positioned anywhere in the cylindrical build volume. Delta printers typically keep the build plate fixed and move the print head in all three dimensions. They are known for fast and smooth motion (less moving mass on the print head) and are especially good for tall prints, since their height can be significant. Calibrating a delta printer is a bit more complex (since movement is not one-to-one with each axis), but modern firmware handles the kinematics. Examples of delta printers include the Rostock, Kossel, and SeeMeCNC’s Artemis. They are eye-catching due to their tripod-like movement and can often achieve higher print speeds for certain shapes.

DLP (Digital Light Processing)

DLP is a resin 3D printing technology similar to SLA, but instead of using a laser to trace each layer, it uses a digital light projector to cure an entire layer all at once. In DLP 3D printing, a projector casts an image of the layer cross-section onto a vat of photopolymer resin, causing that layer to solidify (SLA vs. DLP vs. MSLA vs. LCD: Guide to Resin 3D Printers | Formlabs). After each exposure, the printer advances (usually by lifting the build plate) and exposes the next layer image. Because an entire layer is cured in one flash, DLP can be faster than scanning a laser across the vat (especially for larger layer areas). DLP printers use a DMD (digital micromirror device) chip with an array of tiny mirrors to project the UV light pattern, essentially giving each layer a certain pixel resolution. The term voxel (volumetric pixel) is often used, as each mirror/pixel corresponds to a tiny 3D volume of the cured part (SLA vs. DLP vs. MSLA vs. LCD: Guide to Resin 3D Printers | Formlabs). DLP produces parts with high detail and smooth surfaces, similar to SLA. Many desktop “LCD” resin printers are technically DLP-like (they use an LCD screen as a mask for UV LEDs) – see MSLA below. DLP is used for jewelry, dentistry, miniatures, and any application needing fine resolution. (Keywords: resin 3D printing, projector)

DMLS (Direct Metal Laser Sintering) / SLM (Selective Laser Melting)

DMLS is a metal 3D printing process that is essentially the metal equivalent of SLS. A DMLS machine spreads a layer of fine metal powder and then uses a high-power laser to selectively melt (or sinter) the powder in the pattern of that layer. By repeating this layer by layer, it builds a solid metal part. The result is a fully dense metal object, often with mechanical properties comparable to forged or cast metal. DMLS is used to produce complex metal components in aerospace, medical implants, automotive parts, and more – parts that would be very difficult to make by traditional machining or casting. This technology is also known as Selective Laser Melting (SLM), particularly when the process fully melts the powder (the term “sintering” is a bit of a misnomer, since most machines actually melt the powder completely). For practical purposes, DMLS and SLM refer to the same layer-wise laser fusion of metal powder (Replacement Parts are a 3D Print Away | Machine Design). Parts from DMLS/SLM often require support structures (to anchor down overhangs and manage residual stress) and usually go through post-processing like heat treatment and machining of critical surfaces. DMLS machines can print in materials like stainless steel, titanium, cobalt-chrome, Inconel, aluminum, etc. This process enables direct manufacturing of complex metal parts without molds or tooling.

Dual Extrusion

Dual extrusion refers to 3D printers that have two extruders/nozzles, allowing them to print with two materials or colors in one print job. In FDM printers, dual extrusion systems typically have either two separate print heads (each with its own hotend and nozzle) or a single print head that can accept two filaments (via a splitter or tool-changing mechanism). The main uses of dual extrusion are:

• Multi-material printing: e.g. one extruder prints the main part in PLA, while the other prints a different material like PVA support (which can later be dissolved away), or prints a dual-color object.
• Support material: Printing soluble support structures with a dedicated material (like PVA or HIPS) while the main part is in a different material that might be not easily self-supported.

DfAM (Design for Additive Manufacturing) [Optional]

Design for Additive Manufacturing is an engineering approach that optimizes part designs specifically for 3D printing processes. Unlike designing for traditional manufacturing (which has rules to accommodate casting, machining, etc.), DfAM considers the freedoms and constraints of additive methods: for instance, incorporating organic lattice structures to reduce weight, orienting a model to minimize supports, consolidating multiple assembly components into one printed part, and ensuring features meet the resolution limits of the printer. DfAM is not a single term we define like others, but it’s a concept professionals use to get the most out of 3D printing. By following DfAM principles, engineers can create more efficient, lightweight, and complex parts that would be impossible or too costly to make otherwise. (This term is included for completeness; it’s more of a practice than a glossary definition.)

E

EBM (Electron Beam Melting)

Electron Beam Melting is a powder-bed fusion 3D printing technology similar to SLM/DMLS, but it uses a high-energy electron beam instead of a laser as the energy source. EBM machines spread metal powder layers in a vacuum chamber, and an electron beam (controlled by electromagnetic coils) scans the layer to melt the powder in the desired areas. The process happens in a vacuum and at elevated temperature, which can produce parts with lower residual stresses (the powder bed is kept hot). EBM is typically used with reactive metals like titanium and is common in medical and aerospace industries for implants and structural parts. The technology can build parts faster than laser-based systems (since the electron beam can have a higher energy output and also do some parallel scanning by rapid beam deflection), but layer thickness is usually larger and surface finish is rougher compared to laser-based metal prints (Video: What Is Electron Beam Melting (EBM)? | Additive Manufacturing) (Overview of Electron Beam Melting Technology - MET3DP). EBM parts often require machining for critical surfaces. Arcam (a GE company) is a well-known manufacturer of EBM machines.

Elephant’s Foot

Elephant’s foot is a colloquial term for a printing issue where the first layer (or first few layers) of an FDM print squish outward, making the base of the print slightly wider than intended. It’s called this because it looks like the object’s bottom has splayed out like an elephant’s foot. Elephant’s foot is usually caused by the print bed being a bit too hot or the nozzle starting too close to the bed, causing the very bottom of the print to remain soft and spread under the weight of the object (Ender 3 Pro elephant's foot - 3D Printing Stack Exchange) (3D Printing Terminology: All Important 3D Printing Terms - All3DP ). Insufficient first-layer cooling can exacerbate it. While a well-squished first layer is good for adhesion, too much causes this effect. Ways to prevent elephant’s foot include: lowering the bed temperature after the first layer, raising the nozzle slightly for the first layer, or adding a small chamfer to the bottom of the model in the design (some slicers even have an “elephant’s foot compensation” setting to slightly shrink the first layer dimension).

Extruder

In 3D printing, the term extruder can refer to the entire mechanism that feeds and pushes out material. In FDM printers, the extruder typically consists of a motor, gear, and drive mechanism that pushes filament into the hotend (where it melts) and out through the nozzle. The extruder is responsible for controlling the flow of material – how much plastic is being deposited at any given time. There are two main types of extruder setups: Bowden extruders , where the extruder motor is mounted on the frame and pushes filament through a long tube to the hotend (reducing moving weight at the print head, but requiring more force and having more lag in filament movement), and Direct drive extruders, where the extruder motor is mounted on the print head itself and feeds filament directly into the hotend (more control, better for flexible filament, but adds weight to the moving head). The extruder’s job is critical – if it under-feeds or over-feeds filament, you get under-extrusion or over-extrusion issues. Many printers allow you to calibrate the extruder steps (how many steps the motor turns per mm of filament) to ensure accurate flow. In summary, the extruder is the “feeder” of the printer, melting and depositing filament onto the build plate to create the object layer by layer ( An A to Z Guide of 3D Printing Terminology | Protolabs ). (Note: In resin printers, the concept of an extruder doesn’t apply since resin is cured in place rather than pushed through a nozzle.)

Extrusion

Extrusion in 3D printing refers to the process of expelling molten material from the printer’s nozzle. In FDM, we often talk about extrusion in terms of rates and control – the printer’s firmware and G-code commands (like E values in G-code) regulate how much filament is pushed through the nozzle to form each line or layer. Good extrusion is a balance: too little and you get gaps (under-extrusion), too much and you get blobs (over-extrusion). The term extrusion width is also used to define how wide the laid-down filament track is (usually slightly more than the nozzle diameter). In a broader sense, “extrusion-based 3D printing” refers to any process where material is extruded through a nozzle (FDM/FFF is one, but also some concrete 3D printers or food printers are extrusion-based).

(We have defined Extruder above, which is closely related. Often “extrusion” and “extruder” are used interchangeably in casual talk, but strictly: the extruder is the hardware, extrusion is the action.)

F

FDM (Fused Deposition Modeling) / FFF (Fused Filament Fabrication)

FDM is the most common 3D printing technology for hobbyists and many professionals. In FDM (Fused Deposition Modeling), a thermoplastic filament is fed into a heated nozzle, melted, and extruded out in thin strands that solidify to form layers. The printer lays down material according to the cross-section of the model for that layer, then moves up (Z direction) and repeats layer by layer, building the object from the bottom up ( What is FDM (fused deposition modeling) 3D printing? | Protolabs Network ). It’s valued for its simplicity, affordability, and the wide range of materials available (PLA, ABS, PETG, TPU, etc.). FDM was originally a trademarked term by Stratasys; the open-source community often uses FFF (Fused Filament Fabrication) to describe the same process. Thus, FDM and FFF are used interchangeably to mean depositing melted filament in layers to print a part. FDM printers compose the largest installed base of 3D printers worldwide ( What is FDM (fused deposition modeling) 3D printing? | Protolabs Network ) – from desktop kits to industrial machines. Key considerations in FDM printing include setting the right nozzle temperature, bed temperature, print speed, layer height, and cooling, as well as using supports for overhangs. The layer lines are usually visible in FDM parts, and post-processing (sanding, acetone smoothing for ABS, etc.) can be done if a smoother finish is required. Despite being one of the older 3D printing technologies, FDM remains popular due to its cost-effectiveness and continual improvements.

Filament

Filament is the spool of material that an FDM/FFF printer uses. It’s a long, thin strand of thermoplastic (usually 1.75 mm in diameter, though some printers use 2.85 mm) that is fed into the printer’s extruder. Filament comes in many types and compositions, each with different properties. Common filament materials include PLA, ABS, PETG, TPU (flexible), Nylon, Polycarbonate, and more (An A to Z Guide of 3D Printing Terminology | Protolabs) (3D Printing Glossary: The A To Z Of 3D Printing (2023) | Manufactur3D). Some filaments are composites, where a base plastic is mixed with wood fiber, carbon fiber, metal powder, etc., to give special properties (e.g., wood-like finish, extra strength, or heavy weight).

Filament typically comes on 1 kg spools (or other weights) and should be kept dry, as many materials absorb moisture from the air which can negatively affect print quality (wet filament can hiss or pop as water boils during extrusion and cause brittle or poor-quality prints). When printing, the filament is drawn from the spool by the extruder, pushed into the hotend where it melts, and then extruded out to form the object. The quality and consistency of the filament diameter are important – good filaments have tight diameter tolerances (e.g., 1.75 ± 0.02 mm) to ensure consistent flow. Many users experiment with different brands and types of filament to find optimal settings and results for their particular printer.

Firmware

In 3D printing, firmware refers to the software that runs on the printer’s control board and governs its operation. It’s essentially the printer’s internal operating system, interpreting G-code commands and controlling the motors, heaters, and sensors. Common firmware for hobbyist FDM printers includes Marlin, RepRap Firmware, Klipper, and Smoothieware. The firmware is configured for the specific hardware of the printer (bed size, thermistor types, motor steps, etc.) and often can be updated or customized by advanced users. For example, if you install a different type of extruder or add auto-bed-leveling hardware, you might update the firmware configuration. On the user side, you typically don’t interact with the firmware except by sending G-code via a USB or SD card, but it’s good to know it’s there. In resin printers, firmware also controls screen exposure times, lifting speeds, etc. Essentially, firmware is what translates the high-level print instructions into precise electrical signals to move each stepper motor or heat each element at the right time.

(SEO note: This is a bit technical for beginners, but included for completeness. Casual users rarely need to think about firmware unless they are modifying or troubleshooting their machine.)

G

G-code

G-code is the machine instruction file that tells a 3D printer (or CNC machine) exactly what to do. It’s a series of text commands that indicate movements (like “move to this coordinate”), extrusion amounts, speeds, temperatures, fan on/off, and so on. When you slice a 3D model, the slicer outputs a G-code file, which is then sent to the printer to execute. A typical G-code command might look like G1 X50.0 Y25.3 E0.012 F1800, which means “move in a straight line (G1) to X=50.0, Y=25.3 while extruding E=0.012 mm³ of filament at a feed rate of 1800 mm/min”. There are many G-code commands: G28 homes the axes, M104 sets extruder temperature, M140 sets bed temperature, M106 turns on the fan, etc. (An A to Z Guide of 3D Printing Terminology | Protolabs). The 3D printer’s firmware reads the G-code line by line and executes it, thus recreating the sliced object physically.

G-code is a standardized language (originally from the CNC world), and while the basic commands are common, each type of machine might have custom codes (like M600 for filament change, or specific resin printer commands). For 3D printing purposes, you rarely need to write G-code manually – the slicer does it for you – but understanding it can help in troubleshooting or fine-tuning a print (some advanced users manually edit G-code for custom sequences). For instance, adding a pause or changing temperatures at a certain layer can be done by inserting the appropriate G-code commands. Many slicing software have the ability to include custom G-code at the start or end of a print (start G-code, end G-code) for things like auto homing, warming up, or cooling down sequences.

Ghosting (Ringing)

Ghosting – also called ringing – is a print quality issue where repeated ripples or faint “echoes” appear on the surface of a print, usually near sharp corners or edges. It’s caused by vibrations in the printer frame when the print head makes sudden moves. For example, if the printer has to abruptly change direction around a corner, the momentum can cause it to wobble slightly; this vibration can translate into the print head overshooting and then coming back, leaving behind a pattern of ripples trailing the corner. These ripples look like the “ghost” of the original feature. Ghosting is more pronounced on springy or less rigid printers, or when printing at high speeds/accelerations. To reduce ghosting, you can lower print speed or acceleration/jerk settings in the firmware, ensure the printer is on a stable surface, or upgrade components (stiffer frame, better motion planning via firmware like input shaping or resonance compensation available in some advanced firmwares). It’s mostly a cosmetic issue but can affect dimensional accuracy if severe. In sum, ghosting is the artifact of mechanical vibration, and mitigating it is part of fine-tuning for high-quality FDM prints.

H

Heated Bed (Heat Bed)

A heated bed is a build plate that can be heated, commonly found in FDM printers. The primary purpose of a heated bed is to keep the bottom layer of the print warm, which greatly aids in adhesion and prevents issues like warping (An A to Z Guide of 3D Printing Terminology | Protolabs). Different materials have different bed temperature requirements: for example, PLA typically sticks well around 50–60 °C, ABS often needs 90–110 °C, PETG around 70–80 °C, etc. By maintaining a warm surface, the print’s first layers stay slightly pliable longer and don’t cool unevenly, thus reducing the tendency to contract and lift off the bed (warp). Heated beds can be plain glass, aluminum plates, or other surfaces with heating elements (like PCB heaters or silicone heater mats) attached underneath.

Besides adhesion, a heated bed can also slightly improve layer bonding for the lower layers as they cool more slowly. However, not all materials need a heated bed – PLA is quite forgiving and can be printed on a cool bed with tape or glue stick, for instance. For resin printers, heated beds are not typically used (some industrial ones might heat the resin, but hobbyist resin printers do not). It’s important to calibrate the bed temperature correctly and ensure the heat is distributed evenly. Some printers have removable flex plates on top of a heated bed for easier part removal. When printing finishes and the bed cools, parts often release more easily from the surface. Safety tip: Heated beds draw significant power; always ensure wiring is secure to avoid shorts, and never leave a printer running unattended for long periods as a general precaution.

HIPS (High Impact Polystyrene)

HIPS is a thermoplastic similar in some ways to ABS. In 3D printing, HIPS is often used as a dissolvable support material. It dissolves in limonene (a citrus-based solvent). So, if you have a dual extruder printer, you can print your part in ABS and the support structures in HIPS; after printing, you submerge the object in a limonene bath, and the HIPS supports will dissolve, leaving just the ABS part with clean overhangs. HIPS as a primary material prints with settings like ABS (it requires a heated bed and preferably an enclosure, as it can warp). It’s moderately strong and light, and sometimes used for prototyping or hobby projects on its own. It’s called “High Impact” polystyrene because it’s basically polystyrene (think of plastic model kits or CD cases which are polystyrene) modified to be less brittle. As a dissolvable support, it’s quite useful, though limonene is a somewhat expensive solvent and has a strong citrus smell. One advantage of HIPS is that it sands and paints well, so some use it for making props or models intended to be painted.

(Note: Newer support materials like BVOH or specialized polyesters are also used as soluble supports, but HIPS remains a common and cheaper option especially for ABS.)

Hotend

The hotend is the part of an FDM 3D printer where the filament is melted and extruded. It typically consists of a heater block, a heating element (heater cartridge), a temperature sensor (thermistor or thermocouple), the nozzle, and a heat break attached to a heat sink . The filament is guided into the hotend, where it passes through the heat break into the heater block. The heater raises the filament to its melting temperature, and the molten plastic exits through the nozzle at the bottom. The heat sink (often with a fan) above the heat break keeps the upper part of the hotend cool so that the filament stays solid until it reaches the melt zone – this prevents jams (this is known as maintaining a sharp thermal gradient).

In summary, the hotend is where solid filament becomes molten and gets pushed out to form the print ( Hotend - Wikipedia ). Different hotends can reach different temperatures; a typical brass nozzle hotend goes up to ~260 °C (good for PLA, ABS, PETG), while all-metal hotends (no PTFE liner) can go to 300 °C+ (needed for materials like Nylon, Polycarbonate, or PEEK). There are also specialty hotends for composites or high flow. The nozzle at the tip (which actually shapes the filament into a strand) can be swapped for different diameters; common is 0.4 mm, but you might use 0.2 mm for fine detail or 0.8 mm for fast, thick extrusion. Keeping the hotend clean (free of burnt residue) and making sure the thermistor is accurate are important for consistent printing. Clogged hotends are a frequent trouble – see Clogging under “C.”

I

Infill

Infill is the interior structure of a 3D printed part. In FDM (and other layer printing processes), instead of printing a part as a solid mass of material, we usually print the walls (shell/perimeter) and then fill the inside with a lighter lattice or pattern. This interior sparse filling is called infill. It’s a way to save material and time while still giving the part reasonable strength. Infill is defined by a percentage and a pattern. For example, 20% infill means the interior is 20% plastic and 80% air (approximately), and you might choose a grid, hexagon (honeycomb), triangle, or gyroid pattern, etc., for how the infill is laid out. A higher infill percentage makes a part more solid and typically stronger/heavier, while a lower infill makes it lighter and prints faster. Some functional parts might need 50-100% infill for maximum strength, whereas a decorative model might be fine at 10% or even 0% (hollow).

The slicer lets you set the infill density and pattern. Typically, the printer will print the perimeters (outer shells) of each layer, then fill the interior with the chosen infill pattern. Infill also provides support for the top layers: if you have a roof on your model, you need enough infill density so that when the printer prints the top solid layers, they don’t sag into empty space. Infill density can be varied within a print (some slicers allow setting higher infill only where needed). Choosing the right infill is a balance between structural needs and resource efficiency (An A to Z Guide of 3D Printing Terminology | Protolabs). As a general rule, use just enough infill to meet the part’s functional requirements.

(Related terms: Shells or Perimeters refer to the outer walls; increasing shell count also strengthens a part without affecting infill.)

Input Shaping [Optional]

Input shaping is an advanced feature in some 3D printer firmware (like Klipper) that pre-processes the motion commands to reduce vibration-related artifacts such as ghosting. By characterizing how the printer vibrates (via test prints or accelerometer data), the firmware can “shape” the acceleration profile to cancel out ringing frequencies. This isn’t exactly a glossary term every user needs, but it’s included here as it’s becoming more popular in discussions about improving print quality at higher speeds.

L

Layer Height

Layer height (also known as layer thickness) is the thickness of each horizontal layer of the print, typically measured in millimeters (mm). It is one of the most important settings in slicing a model. A typical FDM layer height is around 0.2 mm for a standard quality print with a 0.4 mm nozzle. Smaller layer heights (e.g., 0.1 mm or 0.05 mm) will produce a smoother surface (less visible layer lines) and can capture finer detail, but will take longer to print because more layers are required to reach the same object height (An A to Z Guide of 3D Printing Terminology | Protolabs). Larger layer heights (e.g., 0.3–0.4 mm with a 0.4 mm nozzle, or even more with a larger nozzle) print faster but you see more pronounced “stepping” between layers.

The layer height chosen should be supported by the nozzle size (as a rule of thumb, layer height should be between 25% and 75% of the nozzle diameter for good quality). For example, a 0.4 mm nozzle prints well in the 0.1–0.3 mm layer range. Very thin layers can also help with overhangs and fine features, while thick layers are good for draft prints where speed is important. It should be noted that reducing layer height does not improve XY resolution (that’s determined by nozzle size and printer mechanics), but it improves Z resolution (smoothness in the vertical dimension). When people talk about “resolution” of a 3D printer, they often mean the minimum layer height it can reliably do, among other things. Ultimately, you choose layer height based on the needed quality vs time trade-off for each print.

Leveling (Bed Leveling)

Bed leveling is the process of ensuring the build plate is perfectly flat (planar) relative to the printer’s nozzle across the entire build area. If the bed is not level (or rather, not properly trammed), one side of a print might start too close to the nozzle (squishing the filament too much) and another side too far (filament might not stick at all). Leveling usually involves adjusting screws at the corners of the bed to raise or lower it until the nozzle distance is uniform. Many printers include a paper test: you move the nozzle to various points on the bed and slip a piece of paper between the nozzle and bed – you want to feel a slight friction consistently at all points. Modern machines often have automatic bed leveling (ABL) sensors – like inductive or BLTouch probes – that measure the bed height at multiple points and then the firmware compensates for any tilt or unevenness by adjusting the Z during printing. Even with ABL, initial manual leveling to get close is helpful.

A well-leveled bed is crucial for a successful first layer, which in turn sets the foundation for the entire print. Some printers have fixed beds and instead use autoleveling only; others require manual tweaking occasionally as things shift over time. Once leveled, some printers can maintain it for many prints unless something is changed (like a new nozzle or different bed surface). Mesh leveling is a related concept where the printer creates a mesh map of the bed’s shape (not just tilt but also any slight curvature or bump) and compensates accordingly. In summary, bed leveling is all about that first layer consistency: too close and you’ll get squished layers or nozzle clogs, too far and the filament won’t stick. A common tip if you see issues on the first layer is “re-level the bed.”

S

STL (STereoLithography) File

STL is the most widely used file format for 3D printable models. An STL file describes the surface geometry of a 3D object as a mesh of tiny triangles (a tessellation of the object’s surfaces). It was originally developed for stereolithography machines (hence the name) by 3D Systems. STL files have no scale units (it’s just numbers, the slicer assumes them as mm by default) and no color or material information – they strictly represent shape. When you export a CAD model to STL, you usually can specify a resolution/tolerance that determines how fine the triangulation is (higher resolution = more, smaller triangles = larger file size but more accurately captures curves).

In practice, when someone wants to print a model, they will likely either find or create an STL file. The STL is loaded into slicer software to be converted into G-code. If an STL model isn’t manifold (has holes or self-intersections), the slicer might have trouble interpreting it; tools like Meshlab or Netfabb can repair STLs if needed. Despite being an old format, STL remains the go-to standard for sharing 3D printable models (you’ll see repositories like Thingiverse or Printables host STL files for download). Newer formats like OBJ or 3MF or AMF offer additional features (like color, materials, units, etc.), but STL’s simplicity and ubiquity keep it popular. Think of an STL as the 3D printing equivalent of a PDF – a universal format that most programs can handle. It’s worth noting that STL is sometimes said to stand for “Standard Triangle Language” or “Standard Tessellation Language” in addition to “STereoLithography”. Regardless, if you have an STL, you likely have what you need to start slicing for print.

SLA (Stereolithography)

SLA is one of the earliest 3D printing technologies and stands for Stereolithography Apparatus. It is a resin-based printing process where a UV laser is used to cure liquid photopolymer resin, solidifying it layer by layer to form a 3D object. In a classic SLA setup, there’s a vat of liquid resin and a build platform that either lowers into the vat from above (or lifts out from below in “inverted” desktop SLA printers). The laser is directed by galvanometer mirrors (or similar) to draw each layer’s pattern on the resin surface or through a transparent bottom, curing the resin where it hits (What is Stereolithography (SLA)?). After a layer is drawn and solidified, either the platform moves (peeling the layer off the bottom in bottom-up systems) or a recoater blade sweeps a new layer of resin for a top-down system, and the next layer is drawn.

SLA is known for its high resolution and smooth surface finish. It can produce very fine details and generally outperforms FDM in terms of accuracy for small features. The materials are liquid resins that cure into various types of plastics (standard, tough, flexible, castable, dental, etc.). However, SLA parts are typically a bit more brittle unless using specialty tough resins, and they can be sensitive to UV light over time (they can continue to cure and maybe discolor if left in sunlight). After printing, SLA parts need to be rinsed (usually in isopropyl alcohol) to remove excess resin and then post-cured under UV light to fully harden. Support structures are usually needed for overhangs in SLA just like in FDM, but they are thin, lattice-like supports that are clipped off and sanded. Companies like 3D Systems (with the original SLA machines) and Formlabs (with popular desktop SLA printers) are key players. SLA is great for prototyping, jewelry casting patterns, dental models, miniatures, and any application needing high detail.

(Note: SLA is often used as a blanket term for resin printing, but other resin technologies include DLP and LCD-based MSLA, which achieve the same end via different light sources.)

SLS (Selective Laser Sintering)

SLS is a powder-bed fusion 3D printing technology that uses a laser to fuse powder particles together into a solid object. In SLS, a thin layer of powdered material (commonly nylon plastic powder, a.k.a. polyamide, though SLS can also be used with other materials like elastomers or even ceramics) is spread across a build chamber. A CO₂ laser then scans the cross-section of the part in that powder layer, heating the particles to fuse them (technically melting them in most systems). Once a layer is done, the powder bed drops slightly and a new layer of powder is spread on top, then the laser sinters the next layer, and so on. The result, after many layers, is a solid part buried in a cake of loose powder. The entire bed is allowed to cool, then the parts are dug out and the excess powder is brushed/blown off and can be reused (often a mix of fresh and used powder is recycled).

SLS is great because the surrounding powder supports the part as it prints, so you don’t need dedicated support structures – this means SLS can produce very complex geometries, including interlocking parts or moving mechanisms, in one print. It’s an industrial technology, often used for functional prototypes or low-volume production of end-use parts (like custom enclosures, drone parts, etc.). Nylon SLS parts are strong, slightly grainy in texture, and usually white/gray (though they can be dyed any color easily). SLS machines keep the powder bed at a high temperature (just below the melting point) to aid the process and reduce warping. The laser fuses each layer’s pattern, essentially “drawing” the object cross-section. According to one definition, “Selective Laser Sintering (SLS) is a 3D printing technology that uses a laser to melt and solidify layers of powdered material into finished objects.” (3D printing technologies: Selective laser sintering (SLS)). SLS is ideal for producing industrial strength parts on demand ( Selective Laser Sintering (SLS) | Nylon 3D Printing Service — 3D People UK), with high accuracy and almost no geometric limitations aside from needing to remove internal loose powder. It’s commonly used with Nylon-12 or Nylon-11 powders, sometimes with fillers (like glass-filled nylon for stiffness). Leading companies for SLS machines include EOS, 3D Systems, and recently Formlabs (with a smaller SLS machine). If you want robust, functional plastic parts without visible layers, SLS is a top choice, though it’s less accessible to hobbyists due to cost and powder handling complexity.

Slicer (Slicing Software)

A slicer is a software tool that converts a 3D model (usually an STL/OBJ file) into instructions that a 3D printer can understand (G-code for most FDM printers, or proprietary slice files for some resin printers). The slicer “slices” the model into horizontal layers based on the layer height you choose, and then for each layer it generates toolpaths for the printer to follow. In essence, it figures out: outlines (perimeters) of the shape, infill pattern, support structures, and any special moves needed. It also inserts commands to control temperatures, fans, etc., usually via a start script (heat up, home axes) and end script (cool down, home, etc.). Users interact with the slicer by adjusting print settings like layer height, infill density, speeds, support options, and more, then the slicer produces the file to be printed.

Popular FDM slicers include Ultimaker Cura, PrusaSlicer (forked from Slic3r), Simplify3D, IdeaMaker, and many others. For resin printers, common slicers are Chitubox, Lychee, or Formlabs’ PreForm (for their printers). Many slicers also provide previews of the toolpaths and estimates of print time and material usage. They often have profiles for specific printer models and materials to help users with the right starting settings. Modern slicers also offer advanced features like variable layer heights, ironing (for top surface smoothing), tree supports, sequential printing, and more. The quality of the final print heavily depends on slicer settings, so learning how to tune and configure your slicer is a big part of mastering 3D printing. In short, without a slicer, your 3D model can’t be printed, because the printer needs that step-by-step layer-by-layer roadmap to follow.

(Internal linking opportunity: Slicers output G-code , which is executed by the printer. Also, slicer settings determine things like infill, support, retraction, raft/brim/skirt, etc.)

Support Structures (Supports)

Supports are temporary structures printed to uphold parts of a model that would otherwise be printed in mid-air. In FDM printing, supports are typically thin towers or lattice scaffolding made of the same (or a secondary) material. They attach either to the build plate or to lower parts of the model and prop up overhanging sections above. For example, if you are printing a model of a person with arms outstretched, the hands would need supports underneath since there’s no material under part of them while printing. The slicer usually can automatically generate supports based on overhang angles – a common threshold is if an overhang is more than 45° from vertical, it might need support. Supports are meant to be removed after printing, so they are made to break away (or dissolve, in the case of soluble supports like PVA or HIPS). They can leave behind rough spots that often need cleanup (sanding or trimming).

In resin printing, supports are more like a tree of thin contacts that hold the part as it grows upward, since resin prints are often upside-down and need to hang from the build plate. Those supports are clipped off and the small nubs sanded.

Designers sometimes tweak their model to minimize the need for supports (e.g., adding chamfers or altering orientation), because supports can waste material, increase print time, and potentially mar the model’s surface. That said, they are essential for achieving certain shapes. Slicers allow control over support density, pattern, and interface layers (a thin separation layer so supports detach more easily). After printing, support removal is a step where you break off all the supports, which can be tedious for complex prints but is just part of the process. For dual extrusion setups, soluble supports are fantastic: you can print complex geometry and dissolve the supports in water or solvent, yielding a clean result with minimal scarring.

(Link: Overhangs and bridging are two related concepts – bridging is like printing a horizontal span between two pillars without support underneath; slight sagging may occur but slicers can handle small bridges. If too long, supports or design changes are needed.)

T

Thermoplastic

A thermoplastic is a polymer material that becomes soft and moldable when heated and solid when cooled, a process that can be repeated multiple times. Thermoplastics are the primary materials used in FDM 3D printing – examples include PLA, ABS, PETG, Nylon, etc. ( What is FDM (fused deposition modeling) 3D printing? | Protolabs Network ). The property of softening with heat (without significant chemical change) is what allows filament to be melted in the hotend and then harden again into the shape of the printed object. Each thermoplastic has a characteristic melting temperature or glass transition temperature that the printer must reach to extrude it. For instance, PLA softens around 60 °C and melts around 180 °C, so it prints around 200 °C; ABS softens around 105 °C (glass transition) and prints around 240 °C. In contrast to thermoplastics, thermosets (like most resins for SLA/DLP) permanently cure and won’t re-melt upon heating. The advantage of thermoplastics is that they can be reshaped and recycled by melting.

In 3D printing context, knowing that a material is a thermoplastic means you can potentially weld pieces (with a soldering iron or acetone for ABS, etc.), or remelt scrap filament. It also means printed parts will soften if they get too hot (leaving a PLA print in a hot car, ~60 °C, can deform it). Common thermoplastics used in printing and their traits: PLA (easy, biodegradable, lower heat resistance), ABS (tough, higher temp resistant, but emits fumes), PETG (strong, a bit flexible, good layer adhesion), TPU (elastic thermoplastic polyurethane), Nylon (durable, wear-resistant, needs high temp), Polycarbonate (very strong and heat resistant, tricky to print), etc. Understanding the thermoplastic behavior helps in troubleshooting print issues – e.g., if layers aren’t bonding, maybe the filament isn’t being heated enough, or cooling too fast (not staying above glass transition long enough to fuse).

TPU (Thermoplastic Polyurethane)

TPU is a type of thermoplastic elastomer (TPE), specifically a polyurethane, known for its flexible, rubber-like properties. In filament form, TPU can be printed with most FDM printers (ideally those with direct drive extruders, as Bowden extruders can struggle with the very flexible filament). When printed, TPU parts can bend, stretch, and compress – think phone cases, gaskets, belts, or even shoe soles. TPU filaments come in different hardness levels, often rated by Shore hardness (e.g., Shore 95A, 85A – lower numbers are softer). A 95A TPU is slightly stiff (like a rubber tire tread), while an 85A is quite soft (like a gel insole).

Printing TPU requires some adjustments: slower speeds (to give time to push the flexible filament accurately), often lower retraction (to avoid the filament buckling or getting stuck), and nozzles might need slightly higher temps to maintain flow. The material tends to string a bit (because it’s stretchy, retraction is less effective), but you can tune settings to minimize it. Once printed, TPU objects have excellent impact resistance and can endure repetitive flexing. They also have good layer adhesion usually, due to the slow cooling (they don’t crystallize like PLA, etc.). However, parts can be a bit “springy” so dimensional accuracy can be off if the part flexes during printing (e.g., tall thin TPU prints might wobble).

TPU is widely used for printing custom phone cases, seals, vibration-dampening mounts, RC car tires, cosplay parts (like straps or flexible pieces), and so on. It opens up a range of applications that rigid plastics can’t serve. Keep filament dry (TPU can absorb moisture which causes print defects) and be patient while dialing in settings for this material, as it’s a bit less forgiving than PLA or PETG. Once dialed, though, it’s a lot of fun to print squishy, bendy objects.

Toolpath

In 3D printing, a toolpath is the trajectory that the printer’s nozzle or print head follows to create each layer of the object. Once a model is sliced, the slicer generates toolpaths for perimeters, infill, support, etc. The concept is borrowed from CNC machining – it’s literally the path the “tool” (in this case, the extruder nozzle or laser, etc.) takes. Toolpaths can be visualized often in the slicer preview as lines. They include not only the printing moves (where material is being extruded or solidified) but also travel moves (when the printer head moves without printing, often retracting filament to avoid stringing).

Optimizing toolpaths is a key part of slicing strategies – for instance, the slicer will decide in what order to print different areas of a layer and how to traverse the model in a way that minimizes travel time or avoids knocking over small features. In advanced cases, you might generate custom toolpaths for artistic or experimental effects. For 99% of users, toolpaths are just what the slicer handles under the hood. But if you ever inspect a G-code file, you’re essentially looking at instructions that define the toolpaths (G1 commands mostly). For example, printing a circle as a perimeter is actually a series of short straight-line toolpath segments that approximate that circle. The term “toolpath” is used generally in discussions about slicing algorithms – e.g., “This slicer’s toolpath for infill is very efficient” or “The toolpaths show some unnecessary travel moves here.”

In summary, the toolpath is the route taken to deposit material for each layer (An A to Z Guide of 3D Printing Terminology | Protolabs). Good toolpaths yield good prints by ensuring consistent extrusion and minimal artifacts, while a poorly planned toolpath might cause issues like too much travel (stringing) or uneven layering.

U

Under-Extrusion

Under-extrusion occurs when the printer is not extruding as much plastic as it should be. Visually, under-extruded prints will have gaps between roads, very thin layers, or even missing layers. The walls may look stringy or not fully fused, and the object may be weak or fall apart. According to one description, “Under-extrusion occurs when too little filament is extruded during a print,” resulting in gaps or missing sections (3D Printer Under-Extrusion: 8 Simple Solutions - All3DP).

Common causes of under-extrusion include: a partially clogged nozzle (filament flow is restricted), filament slipping in the extruder (the gear can’t push it enough, maybe due to it being too tight/loose or ground down), the print temperature being too low (filament isn’t melting quickly enough to flow at the commanded rate), or the slicer’s settings being off (e.g., filament diameter set incorrectly or extrusion multiplier too low). Also, if the printer is trying to print too fast, the hotend might not keep up (this is called exceeding the hotend’s volumetric throughput capacity) which results in under-extrusion. Moist filament can sometimes cause under-extrusion if it bubbles and disrupts flow.

Fixing under-extrusion depends on the cause: cleaning the nozzle, checking the extruder for tight grip and no slipping, raising the print temperature a bit, slowing down print speed, and verifying slicer settings (do a extrusion calibration if needed to set the flow rate). One quick test is to try manually extruding filament in air and see if it comes out consistently. Under-extrusion is essentially the printer “starving” the print of plastic. It’s one of the more common issues and can be frustrating, but methodically checking the above factors usually resolves it. Keep in mind, slight under-extrusion might show as thin gaps in top layers or infill not touching walls; severe under-extrusion leads to very poor structures. Also, it can happen intermittently (for example, if a nozzle clog starts and stops). Good maintenance and calibration help avoid it.

UV Resin (Photopolymer Resin)

UV resin , often just called resin in 3D printing, is the liquid material used in SLA, DLP, and MSLA printers. It’s a photopolymer, meaning it solidifies (polymerizes) when exposed to certain wavelengths of light (typically ultraviolet). The resin usually comes in bottles and can be a bit viscous. When you run a resin printer, the resin is poured into a vat and either a laser or UV light source cures it layer by layer into the desired shape.

There are many types of 3D printing resins: standard (which cure into a fairly brittle acrylic-like plastic), tough or ABS-like (formulated to be less brittle), flexible (rubbery end result), castable (for jewelry, burns out cleanly), dental/biocompatible resins, high-temperature resins, etc. They also come in various colors and even transparencies. Some resins are specifically made for faster curing or for lower odor, etc. There are also water-washable resins that can be cleaned with water instead of alcohol (though handling and disposal still need care).

Working with resin requires precautions: the liquid resin is toxic/irritant, so you need to wear gloves and avoid skin contact. Good ventilation is recommended as the fumes have an odor and can be sensitizing. After printing, parts are usually covered in uncured resin which must be washed off (commonly in isopropyl alcohol or similar). Then the parts need post-curing under UV light to reach full strength. The leftover resin in the vat can be reused (through a filter to remove any bits) for another print, but you shouldn’t pour resin down the drain – any waste resin or used alcohol must be properly cured (by exposing to sunlight/UV which solidifies the resin, then it can be disposed of as solid waste).

Resin produces highly detailed prints but the process and cleanup are messier compared to FDM. Also, resin prints, being photopolymers, can be somewhat brittle (unless using special flexible/tough formulations) and might not hold up under long-term UV exposure (they can discolor or become more brittle over time if left in the sun). Storing resins properly (cool, dark place) and using within shelf life is also important for consistent results. Despite these caveats, UV resins are fantastic for applications needing fine detail, smooth surfaces, and complex geometry that an FDM printer might not reproduce as nicely.

V

Voxel

A voxel is short for “volumetric pixel” – essentially, the smallest distinguishable box-shaped part of a 3D grid. In 3D printing, we talk about voxels mostly in the context of digital light processing and other high-resolution processes. If you imagine a 3D printer’s build volume divided into a 3D grid (like a 3D bitmap), each tiny cube is a voxel. In practical terms, for a DLP or LCD-based resin printer, the X-Y resolution is defined by pixels of the screen, and the Z resolution by the layer thickness; so one could say the voxel size is X pixel size × Y pixel size × layer height. For example, a printer with a 50 µm XY pixel size and using 50 µm layers is effectively working with 50 µm cubic voxels (in reality, layers are discrete but continuous in XY, so it’s a bit not exactly a cube in how it prints, but you get the concept).

Voxel is a useful concept when printers have true 3D control, like some newer printers that can vary exposure within a layer (so they could potentially address sub-layers). It’s heavily used in medical and scientific contexts (CT/MRI scans are in voxels). In additive manufacturing marketing, you might hear things like “voxel-level control”, meaning the printer can control material or color at each tiny 3D element of the object. For instance, full-color 3D printers like PolyJet or HP Multi Jet Fusion effectively place droplets/inks at the voxel level to create color gradients inside an object.

Another place voxels come in is in software: some model design or scan data are voxel-based (3D pixels) rather than mesh-based. But for a typical user, voxel is just a fancy way of thinking about resolution. If you think of an old 8-bit video game with big pixels – now imagine a 3D version of that. Each voxel = one little cube of material. Voxel size determines the detail: smaller voxels = higher potential detail. As Raise3D’s guide succinctly put it: “A voxel, also known as a volumetric pixel, is the smallest unit of a 3D print, similar to how a pixel is the smallest unit of a digital image.” (What is Digital Light Processing (DLP) 3D Printing: Benefits, Applications, Materials and Costs – Raise3D: Reliable, Industrial Grade 3D Printer).

W

Warping

Warping is a common 3D printing problem where the bottom of a print (or sometimes other sections) curls up or distorts from its intended shape. In FDM printing, warping typically refers to the corners of a print lifting off the bed. This happens due to thermal contraction: as the hot plastic cools, it shrinks. If the bottom layers cool too quickly or don’t stick strongly, they will contract and pull upward, causing the part’s edges to curl. Large ABS prints are notorious for warping – you might start a print flat, and then find the corners several millimeters off the bed. Warping can ruin dimensional accuracy and lead to layer separation (cracks) in the print. It’s essentially the print trying to relieve internal stresses caused by uneven cooling. As one source defines, “Warping is the distortion of a part from its intended shape.” (3D Print Warping: Why It Causes and How to Prevent It - WayKen).

To combat warping:

• Use a heated bed (keeps bottom layers warm so they cool gradually and stick down) (An A to Z Guide of 3D Printing Terminology | Protolabs).
• Use adhesion helpers like a brim or raft to hold those edges down.
• Enclosures help a lot, especially for ABS, by keeping the ambient temperature higher so the whole print cools slowly and evenly.
• Choose materials less prone to warping: PLA hardly warps at all, whereas ABS, Nylon, and Polycarbonate are more challenging. PETG is in-between (minor warping).
• Ensure the bed is properly leveled and surfaces are clean for maximum adhesion.
• In extreme cases, design modifications can help (e.g., chamfer bottom edges so warping, if it happens, doesn’t affect the part’s functional dimensions as much).

Watertight (Sealability) [Optional]

Watertightness in 3D printing can refer to two things: a model being manifold (which we covered under 3D Model needing to be “watertight” in a topological sense), and a printed part’s ability to hold water (functional watertightness). For the latter, printing at 100% infill or using vase mode (single perimeter) can create vessels that hold liquids. Some materials (PETG, Nylon) are better for waterproof prints, and sometimes a sealing coating is used. This term might be out of scope for a core glossary, but it’s sometimes mentioned (e.g., “Is this vase watertight or will it leak?”).

X

X, Y, and Z Axis

These refer to the three axes of motion in a typical 3D printer (see Axis under “A” for more details). To reiterate in brief: the X-axis usually runs horizontally (left-right), the Y-axis runs front-back, and the Z-axis is vertical (up-down). Movements along X and Y change the horizontal position of the nozzle relative to the bed (or vice versa), and movement in Z changes the layer height position. Printers are designed around these axes: e.g., you might have a gantry that moves in X and Y, and the bed moves in Z (typical Cartesian), or in a delta, the combination of movements yields X, Y, Z positioning. You’ll often hear terms like “X-axis belt”, “Z-axis lead screw”, or “Y-axis gantry” referring to the mechanical components for each axis.

During printing, the firmware ensures that all motions are coordinated in X, Y, Z (plus E for extrusion) so that the material is placed exactly where it needs to be. Calibration steps like axis endstops or homing make sure the printer knows its zero position on each axis. Also, things like print dimensions being off can be due to steps-per-mm calibration on a particular axis. For example, if your printed cube is 20 mm in X instead of 20.1 mm, you might adjust the X-axis steps. But such calibration is usually done at the factory or when assembling a kit.

In some printers, axes can be swapped conceptually (e.g., some have the bed move in Y and the head in X and Z, etc., but it’s still the same idea). And in non-Cartesian printers (delta, polar, SCARA), there aren’t literal X, Y linear rails, but the motion ultimately is translated into X, Y, Z movement of the toolhead in space. If you encounter G-code, you’ll see commands like G1 X100 Y50 Z0.2 – meaning move to that coordinate. Many slicers allow you to scale or mirror models in X, Y, or Z to adjust print dimensions. So understanding which direction each axis corresponds to on your printer helps when, say, you tighten belts or troubleshoot (e.g., “my X axis is slipping, circles come out skewed in X direction”).

(In summary, X, Y, Z axes define the 3D coordinate system for printing. Mastery of your machine includes knowing which physical direction is X vs Y, etc. Typically, if you look at a printer head-on: X is left-right, Y is towards-away, Z is up-down, though conventions can vary.)

Y

(See X, Y, and Z Axis above. There isn’t a distinct term starting with Y beyond the axis itself. Perhaps Yield Strength could be a material term, but that’s too detailed for this glossary’s scope.)

Z

Z Offset

Z offset is a setting or adjustment that shifts the starting height of the nozzle relative to the bed. It’s essentially how much you want to move the nozzle up or down from the printer’s determined “home” Z=0 position when it starts printing. A common use of Z offset is if you have a probe for auto-leveling; you probe the bed (which sets a certain reference), then you apply a Z offset so that the first layer is squished just right. For example, if your first layer is not sticking because the nozzle is too high, you apply a negative Z offset (like -0.1 mm) to bring it closer. If the nozzle is scraping or the first layer is too squished, you put a positive Z offset (like +0.1 mm) to raise it.

Many printers allow tuning the Z offset live during the start of a print (e.g., “baby stepping” in Marlin firmware) so you can dial in that perfect first layer on the fly. Once set, the idea is you don’t have to readjust it often unless something changes (new build surface, different filament maybe). Some people also intentionally use a Z offset to achieve a specific effect, like a thicker first layer or to account for a brim that they want a tiny gap under, etc., but those are less common.

Z offset can also refer to adjusting for things like putting a glass plate on the bed (which effectively raises the surface, so you adjust Z offset to compensate). Or in multi-nozzle setups, you might have Z offsets between nozzles. It’s a small but important detail in getting prints to start correctly: think of Z offset as the fine-tuning of the nozzle-bed distance without re-leveling the whole bed.

Z-Wobble

Z-wobble is an imperfection that can appear in prints as a periodic ripple or banding on vertical surfaces, usually aligned with the thread of the Z-axis lead screw. It’s caused by slight mechanical inaccuracies or bent rods that make the nozzle move in a small XY circle as it goes up in Z. Essentially, instead of a perfectly straight up motion, the Z axis might “wobble” due to a misaligned or bent screw/rod, translating into the print. The result is a sort of cyclic bulging often every certain number of layers (matching the lead screw pitch, like every 0.8 mm for a typical 8 mm screw with 2 mm pitch if two-start).

In older or cheaper printers with threaded rods, Z-wobble was a common issue. Modern printers often use better lead screws and couplers that minimize this. Solutions include: using flexible couplers between motor and lead screw, ensuring the screw is straight and not binding, adding linear guides to stabilize the Z motion, or even software compensation. Some people have replaced threaded rods with belts or different mechanisms to eliminate Z banding. It’s more of a hardware flaw than a user error.

Z-wobble shows as consistent waves on the side of a print, which is different from random layer thickness variations (that could be extrusion issues) or intentional layer lines. If you suspect Z-wobble, rotating the screw and feeling for bent points, or watching the nozzle as it raises (does it shimmy side to side?) can diagnose it. Fixing it might require some printer tweaks. In short, Z-wobble is an unwanted artifact tied to the Z-axis mechanics. A good printer should have nearly none – any slight banding could also be caused by subtle extrusion fluctuations or other things, but true wobble is distinctive.