Common 3D Printing Terms and Abbreviations

Curtis Satterfield, Ph.D.

Curtis Satterfield, Ph.D.

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As you learn about 3D printing you will no doubt come across terms and initialisms that you haven’t heard before. On this page you will find a list of definitions for common and not so common 3D Printing terms. The page is divided into sections that are then alphabetized. Filament and resin types are included at the end in their own sections.

If you are looking for reviews of 3D printers check out my recommended FDM printers here and my recommended resin printers here.

We will start with the most common and basic term.

3D Printer – A machine that creates a 3-dimensional object from a digital file in an additive manufacturing process.

Additive Manufacturing – The process of manufacturing an object by adding materials to it as opposed to removing objects. 3D printing is a type of additive manufacturing. Subtractive manufacturing use processes such as mills and lathes to remove material from a piece of stock to arrive at the final shape. Additive manufacturing starts with nothing and adds material until the final shape is completed.

Bioprinting -The process of using 3D printing technology to print living cells such as skin or organs. This is an extremely complex process that is still in its infancy.

Makerspace – A building or space that is designed for learning, making, and sharing using a variety of tools and equipment. Makerspaces are open to many different age groups (dependent on the makerspace) and offer classes and community events to help teach and inspire others. A makerspace will often contain a variety of equipment such as; 3D printers, laser cutters, CNC routers, metal working tools, electronics stations, and even sewing machines.

Fused Deposition Modeling (FDM) Printing

Axis Binding – A mechanical problem that prevents a printer from moving freely in the X, Y, or Z axes.

Bed Adhesion -The ability of the print to stick to the bed during the print process. Low bed adhesion will result in curling or warping of the lower layers. In extreme cases the entire print will break free from the bed causing a failed print.

Belt – A toothed gear belt that is used to transfer movement between the stepper motors and the moving components of the 3D printer.

Benchy – The ubiquitous 3D printer calibration model. This tiny tug is arguably the most famous 3D model ever designed. You can read more about Benchy at 3dbenchy.com

Bridge/Bridging – Printing filament over an open gap between two parts of a model without using supports. Some slicers will have special settings to allow you to tune your bridges for better quality and success.

Blob -Small spots of plastic on the surface of a print also known as zits.

Bowden Extruder -A Bowden extruder is mounted on the printer’s frame and pushes filament through a long PTFE tube to the print head. This reduces weight on the printer carriage resulting in cleaner movement.

Brim – A perimeter of plastic that is added to the base of the 3d object being printed by the slicing program. Adding a bring can help improve bed adhesion and prevent warping.

Build Plate\Platform -The area on the printer that the print adheres to while printing. This area is often made of metal can be heater or unheated. Some printers will have removable build plates made of PEI or a thin metal and other printers can have glass beds.

Build Volume -The area measured in millimeters that the printer can print.Typically denoted as X-dimension x Y-dimension x Z-dimension mm. For example, the Creality Ender 3 has a build volume of 220 x 220 x 250mm.

CAD – Computer Aided Design is the use of computers to create modify, optimize or analyze a design. An example of CAD software is AutoDesk Fusion360.

Calibration – A series of steps used to improve the quality and reliability of a 3D printer.

Carriage – The assembly that holds the nozzle and hot end of the extruder. On a direct drive printer, the carriage also houses the extruder motor.

Control Screen – An LCD screen (sometimes a touch screen) that displays information and aids in selecting settings and manipulating the printer.

Cooldown – The process of letting the hot end and/or heated bed cool. This process happens automatically after a print is finished.

Cura – 3D printer slicing software developed and maintained but Ultimaker.

Direct Drive Extruder – A direct drive extruder pushes the filament directly into the nozzle. This method results in better extrusion but adds weight to the print carriage. The added weight reduces maximum print speed and can result in loss of accuracy in the X and Y axes.  

End Stop – Mechanical switch used to indicate the zero position of an axes.

Elephant’s foot – When the bottom layer(s) of a print are wider than they should be. This is caused by a Z-offset that is too close to the bed.

Extrude – Dispense melted thermoplastic from the hot end onto the build platform or previous layer.

Extruder – This is the part of the printer that contains the heat block, heater, and nozzle. It is used to melt the plastic and extrude it onto the build area or previous plastic layers of the model.

Extruder Fan – A fan that is used to cool the heat sink of the extruder.

Extruder Motor -The stepper motor that is responsible for driving the filament through the heated print nozzle. The extruder motor has a toothed wheel that grips the filament and pushes it down into the heated nozzle.

Extruder Release Lever – A trigger lever applies pressure to the extruder gear releasing tension on the filament. This lever is typically used when changing filaments.

Extrusion Multiplier – A value that is used to modify the flow rate of filament during extrusion. The modifier can be changed to adjust the amount of filament that is extruded.   

FDM – Fused Deposition Modeling is a technology that uses a melting and extrusion method to deposit layers of plastics one on top another.

Filament -The plastic material that is melted to form the 3D object. Filaments come in 1.75mm and 3.0mm with 1.75mm being the most common. Filaments also come in a variety of materials. See the filament section below for more information.

Fill – The interior of a 3D object that connects the top, bottom, and side layers.

Fill Density – A percentage value that determines how much of the model’s interior is filled with plastic. Values range from 0 – 100%

Firmware – The software built into the 3D printer responsible for making the printer work. The firmware contains configurable settings that can be accessed via USB connection to the printer. Marlin is the most popular version of firmware for 3D printers.

Functional Prototype – A close to final model or representation of a product created to test and evaluate the form, fit, and function of the object.

Gantry – The extruder assembly and X-axis motor that moves up and down on the Z-axis of a printer.

G-Code -A programming language used for computer numerical control (CNC) used to automate machine tools. G-Code is produced by a slicing program and gives the 3D printer explicit commands on how to move and operate for each step of the print.

Gravity -Not a 3D printing specific term but one that has great effect on overhangs, islands, and bridges.

Heated Bed – A build platform that has a heating element attached underneath. Heating the bed helps with bed adhesion by preventing warping.

Heater Block -A piece of metal with recesses for the heater and temperature probe. The heater heats the large piece of metal which in turn heats the nozzle and melts the filament. A piece of metal larger than the nozzle is used to help with heat consistency. The nozzle screws into the heat block and the filament passes through the nozzle which is heated by the block.

Hot End -The heated part of the extruder assembly including the heater, heat block, thermistor, and nozzle.

Infill – A pattern that is used to fill the inside of a 3D print. A slicer will hollow the body of a model allowing you to fill it with 0 – 100% plastic. Different infill patterns are used to achieve different properties such as strength. Using less infill results in a faster print time but a weaker overall print.

Kapton Tape – Heat resistant tape used to secure wiring and sometimes used to insulate the hot end of the extruder. Also can be applied to heated beds to increase adhesion.

Layer -a 3D print is created by extruding plastic in layers one on top the other. A layer is a single slice of the print in the XY axes.

Layer Height/Thickness – Layer height refers to the thickness of each printed layer. The most common layer heights are .01 and .02mm.

Layer Separation -During the printing process the print will begin to separate between layers. This can be cause by printing too cold or not enough heat for certain filaments such as ABS.

Layer Shifting – Layers of the print are misaligned or shifted relative to where they were supposed to print. This can happen if the printer is missing steps while printing or a mechanical defect does not allow the printer to move freely in the X and/or Y axes.

Material Extrusion – The act of dispensing material through a nozzle.

Mesh – A collection of polygons attached by vertices and edges that make up a net-like surface area. 3D modeling programs can show the mesh outline of a 3D model.

Minimal Layer Time – The least amount of time required for a layer of a printed object to sufficiently cool before printing another layer on top of it.

Model – A digital representation of the physical object stored in a digital file. Models are designed with 3D modeling software and must be prepared for 3D printer using a slicing program.

Nozzle – The metal tip that the melted plastic extrudes from. Nozzle size is measured in millimeters with the most common size being .04mm.

OBJ – Object file. An alternative format to STL files for storing 3D models.

Oozing – Filament leaking from the nozzle while not engaged in a printing move. Oozing can happen as the printer heats up to printing temperature or while moving from one island to another on the print.

Orientation -How the model is oriented during the printing process. Often, we print the model in an orientation that is different than how the final model will be used. For example, if I want to print a hook that hangs on a door, I will print in laying on its side so that the layer lines run perpendicular to how the hook will take weight. By weighting the object perpendicular to the layer lines, we increase the strength of the model.

Over-Extrusion – When the printer extrudes too much plastic during the print causing prints to look messy.

Overhangs – Parts of a model that are steeper than 45. Most printers can safely print vertical angles of up to 45°, attempting to print steeper angles will typically result in a failed print. The tolerance for overhangs depends on your printer, calibration, and material being used.

Overheating – The extruded plastic gets too hot during the printing process resulting in deformation of the plastic.

PEI – Polyetherimide is a low maintenance plastic that makes an excellent build surface for multiple material types. PEI does not require adhesives such as glue or tape for the 3D Print to adhere to the PEI.

Perimeter – A continuous line that forms the boundary of a closed geometric figured. For 3D printing the edges of each layer create the perimeter.

Preheat – Heating the element prior to using. In 3D printing, you need to preheat the nozzle and/or heated bed before printing, loading, or unloading filament.

Print Head/Print Carriage – The unit that holds the heater block, nozzle, cooling fans, and extruder motor (for direct drive extruders).

Print Bed -Another term for build plate

Print Speed – The rate at which the 3D printer moves and extrudes plastic during a print. Higher speeds result in lower print times. Lower speeds result in higher print times but better-quality prints.

Print Quality – The quality of the final print is determined by several factors including quality of the printer, calibration, material used, slicer settings, print speed, supports, and print orientation.

Printing Temperature – The temperature that the hot end is set to during the printing process. Filaments will have a range of temperatures that they print at and calibrating the printing temperature for each filament you use will result in better print quality.

Printing Volume – The maximum size the build area of a 3D printer can accommodate.

Raft – An option to increase bed adhesion, a raft will print several layers of material on the build plate to eliminate irregularities and unevenness on the platform. The object is then printed on top of the raft.

Removable Bed -A piece of material such as PEI or thin metal that can be removed from the printer’s build platform. A removable bed can make part removal much easier.

Repetier Host – An open source slicer program that is used to prepare STL files for printing.

RepRap – Replicating rapid prototypers are open-source 3D printers that use the FDM fabrication process. RepRap machines should be able to print most of its own parts. Plans and build instructions are freely available from reprap.org

Resolution – Refers to the accuracy of the 3D printer typically in the Z-direction. The lower the layer height that the printer can produce, the higher the resolution.

Retraction – The process of reversing the extruder motor to release pressure on filament in the nozzle. Retraction reduces filament oozing from the nozzle and stringing between islands on your print.

Ringing – Vibrations from the printer that cause oscillations on the surface of the print.

SD Card – Non-volatile storage cards that are used to transfer print files from a PC to the printer. The printer reads the G-Code file from the SD card while printing.

Seam – The point at which the beginning of the layer line and the end of the layer line meet.

Shell – The outer perimeter of a printed object created by the edges of all the layers in the print.

Shell Thickness – The total width of the outside perimeter of a print. The shell thickness should be a multiple of the nozzle size. Two shells are typically enough, but more shells will result in a stronger model. More shells will also result in a slower print.

Skirt – A number of perimeters that are printed offset from the first layer of the object. Printing a skirt helps clean the nozzle of an ooze or filament that was released during the preheat and to prime the nozzle before starting the first layer of the object.

Slice – Changing an STL file into a machine-readable G-Code file.

Slicing Software/Slicer – The software used to convert a 3D model into G-Code that can be read by the 3D printer. Ultimaker Cura is an example of a common FDM slicer. ChituBox is an example of a resin printing slicer.

Soft Pull – Heating the filament currently loaded into the printer to the transition temperature and removing it from the extruder by pulling it out.

Spool – The plastic ring that filament comes on.

Supports – Supports can be used to help with printing overhands of greater than 45 degrees or any floating parts that need to be printed before it connects to the main body of the print.  

STL – The most popular file format for 3D printing. An STL file represents a 3D object in a digital file format. The file describes the object as a series of triangles. What STL actually stands for is unknown but two possibilities include standard triangle language, and standard tessellation language.

Stringing -Thin spiderwebs of filament that connect separate parts on a print when there should not be any connection.

Thermoplastic – A polymer material that softens when heated and solidifies when it cools. FDM filaments are an example of thermoplastics.

Travel Speed – The rate at which the printer carriage will move to a new position on the print while it is not extruding.

Under-Extrusion – When the printer does not extrude enough material while printing resulting in gaps between the perimeter and infill lines.

USB Connection – Universal Serial Bus, is a connection type used to connect peripherals to a computer. A USB connection is often used to control a 3D printer directly from a computer.

Vitamin – A part for a 3D print or printer that cannot be 3D printed.

Warping – Print warping occurs due to material shrinkage while 3D printing. Warping is typically observed as the edges of a print curling up and becoming detached from the print bed. If a print cools down too fast this can lead to warping. Using a heated bed can help prevent warping in prints.

X-Axis – The principal horizontal axis of the printer and coordinate system.

Y-Axis – The secondary horizontal axis of the printer and coordinate system.

Z-Axis – The primary vertical axis of the printer and coordinate system.

Z-Banding – A periodic pattern on the sides of a 3D printed object that resembles a patterned ribbed texture. Z banding gives prints a rough texture and can reduce adhesion between layers.

Z-Lift – The act of lifting the hot end slightly prior to a retraction or movement.

Z-Wobble – A problem with a 3D printer wherein the layers are not printed perfectly aligned with the layers above and below. Z-wobble will cause noticeable Z banding on the sides of a print.

Zits – Small spots of plastic on the surface of a print also known as blobs.

Resin Printing

Build Plate Adhesion -The ability of the print to stick to the build plate during the print process. Low build plate adhesion will result in curling or warping of the layers attached to the build plate. In extreme cases the entire print will be pulled off the build plate as the print releases from the FEP each layer.

Build Plate – The metal plate that cured resin adheres to during the print process.

Calibration -A series of steps used to improve the quality and reliability of a 3D printer. For resin printer’s calibration mainly consists of determining exposure times for different resins.

Curing -Exposing the 3D resin to UV light in order to turn it from a liquid to a solid.

DLP – Digital Light Projector. This refers to the screen and light source used to cure resin in a DLP resin printer. An ultra-violet light source shines through and LCD screen that displays a negative image of the shape of the layer that is being printed. The UV light hits the resin and causes it to harden.

Elephant’s foot -When the bottom layer(s) of a print are wider than they should be. This happens if you print your model directly on the build plate. Because the first few layers of a resin print are over exposed to ensure adhesion any part directly touching the build plate will have the first few layers oversized.

Galvanometers – Small mirrors that direct the laser onto the area of the print to be cured on an SLA printer

Layer -a 3D print is created by curing resin to the layer above it as the build plate rises from the resin vat. A layer is a single slice of the print in the XY axes.

Layer Height – Layer height refers to the thickness of each printed layer. The most common layer heights are .005 and .002mm.

Photopolymerization – The process of solidifying photosensitive resins with a UV light source. DLP and SLA printers use photopolymerization.

Post-processing – The process of washing any residual unhardened resin from the print and then exposing it to a UV light source in order to finish curing the print.

Resin – A photocuring chemical consisting of monomers that form into polymers when exposed to UV light.

Resolution – Refers to the accuracy of the 3D printer typically in the Z-direction. The lower the layer height that the printer can produce, the higher the resolution. Also refers to the resolution of the LCD screen in DLP style printers.

SLA – Stereolithography is a resin printing technique that uses a laser and galvanometers to expose the resin during the print.

Slicer – The software used to convert a 3D model into G-Code that can be read by the 3D printer.

Viscosity – Measure of a fluid’s resistance to flow. The higher the viscosity the thicker the fluid.

Wash – Rinsing the print in a solvent such as Isopropyl alcohol to remove any residual resin from the print.

Ultra-Violet Light Source – A light source that produces ultraviolet light on a wavelength that cures the resin. Most home use printer resin requires a wavelength of 405 nano meters.

Filament Types

ABS – Acrylonitrile Butadiene Styrene is a common filament type known for being tough and impact resistant.

HIPS – High Impact Polystyrene is a 3D printing material that can be dissolved with limonene and is used as removable supports on prints.

PLA Polylactic Acid is one of the favorite filaments of the 3D printing community. It is a biodegradable thermoplastic derived from renewable sources such as cornstarch, sugar cane, and potato starch. PLA requires a much lower nozzle temperature than ABS printing between 180°C and 220°C.

PET Polyethylene Terephthalate is often used for mechanical parts that require flexibility and impact resistance. PET offers more flexibility than ABS while maintaining strength. PETG is printed at temperature like ABS between 220°C and 250°C

PETG Glycol modified Polyethylene Terephthalate (PETG) is a variant of PET filament that increases the materials durability and impact resistance. Unlike PET this material will not readily absorb water. PETG is also considered food save and can be used for cups, plates, and food containers.

PETT – PolyEthylene coTrimethylene Terephthalate (PETT) is another modified version of PET. PETT is considered food safe and is approved by the FDA.

Nylon Polyamide filament is a synthetic polymer typically used in industrial applications. Nylon is strong, durable, and flexible. Printed between 220°C – 250°C nylon is perfect for industrial parts such as gears, bearings, and mechanical components. The downside to nylon is that it emits toxic fumes when printing. This is important to know as nylon does not produce and odor when it prints but it is toxic and should be used in a well-ventilated area.

Wood filament – Made with recycled wood and polymer binding. It is typically used for more decorative applications as it is one of the weaker printing materials.

Resin Types

Standard resin -Basic and usually lowest priced resin. It can come in a variety of colors and is opaque in appearance. Standard resin typically has low viscosity allowing the resin to flow freely during the printing process. Standard resins are designed to reduce part shrinkage when cured. Standard resins also tend to be brittle when cured and may not work well for functional parts requiring high strength.

Transparent resin -Another form of standard resin. Transparent resins differ from other standard resin as their appearance is transparent instead of opaque. An interesting aspect of transparent resin is that the UV light can past through the current layer into preceding layers of the print. Because the transparent resin does not absorb the UV light as readily, exposure times for transparent resin tend to be longer. Transparent resin shares the same mechanical characteristics of standard resin.

Casting Resin – is used in various industries like jewelry making and metal casting. This resin is designed to be “burned out” in a process like lost wax casting. Castable resins tend to be made with waxes that melt when exposed to high temperatures. These resins are designed for this specific purpose and do not work well for other uses.

Tough Resin – designed to have higher strength than standard resin. Tough resin is designed to mimic the mechanical characteristics of ABS plastic. Tough resin is ideal for functional prototypes as it produces strong parts that are less likely to shatter. With tough resin you typically need your parts to have a minimum wall thickness. Trying to print models with thin walls can result in failed prints.

Flexible Resin – is ideal for medical devices, anatomical models, special effects props, and anything that needs to bend and move. The main difference between flexible resin is how much flex the final part has.