Glossary of 3D Printer Terms

3D Printing: A term that is commonly used to describe any process in which a solid tangible object is created from a computer model. It is often used interchangeably with additive manufacturing.

Breakaway Support Technology (BST): Used by printers which add disposable supports to sloping, or overhanging parts. These supports then have to be manually removed by hand when the object is complete.

Brim:  See Raft.

Build Envelope: The maximum physical size of print that can be produced by a specific 3D printer. Build envelopes vary greatly, and are an important consideration when choosing a 3D printer.

Build Plate (Heated Bed, Print Bed, or Build Plate):  Type of build plate used in many 3D printers which keep the base of the build object warm to prevent the object from cooling unevenly and warping as a result.The surface of the 3D printer on which the 3D printed part is formed. Also known as ‘bed’ or ‘build plate’.

Calibration: Alignment of one part relative to another, such as the parallel alignment that would be found between the print bed and extrusion nozzle of a 3D printer.

Curling: An upward contraction of extruded filament from the bottom outer edges of a print inward due to factors such as uneven heating and cooling.

DLP (Digital Light Processing): A display device based on optical micro-electro-mechanical technology that uses a digital micro mirror device. This technology is used in DLP front projectors, but also used in additive manufacturing as a power source in some printers to cure resins into solid 3D objects.

End-Stop:  RepRap’s Cartesian axes all need a datum (also known as home position or end-stop) to reference their movements. At the start of each build each axis needs to back up until the datum point is reached. The switches also help protect the machine from moving past its intended range and damaging itself.

Extrude: The act of placing the build material on the build platform, normally by heating thermoplastic to a liquid state and pushing it through a small nozzle in order to build up a 3D object as it cools and solidifies.

Extruder: The part of a 3D printer which consists of a cold end to pull in the build material and a hot end to melt and extrude the build material.

Dual Extruder: An extruder with two nozzles that allows for printing with multiple colors, textures, and resolutions. Dual extruders also allow for simultaneous printing.

Filament: The wire made from build material (commonly 1.75mm or 3mm in diameter) which enters the cold end of the extruder, or the heated wire (commonly less than 1mm in diameter) which exits the hot end of the extruder.

Functional Prototype: Representation of a final object to test out it’s form, fit and function, but without necessarily using the final materials, colors or texture.

Fused Deposition Modeling (FDM): Both the term and it’s acronym are trademarks of Stratasys. The equivalent term fused filament fabrication is often used instead as it has no legal constraints unlike the trademarked versions.

Fused Filament Fabrication (FFF): The process of building up an object by depositing a material on top of or next to other material in order to join the two, usually by using heat or adhesion.

Hot End: Nozzle part of an extruder which heats the build material and extrudes it to build up the final object.

Infill: The interior structure of a 3D printed model. To avoid wasting plastic, 3D prints are typically printed with an inner mesh structure rather than a solid interior. The infill is typically expressed as a percentage (ex. 20% infill).

Layer Thickness: The layer resolution (or layer height) describes the thickness of one layer of the 3D print. If the default layer resolution is 0.1 mm (100 micron), but it can even reach a 0.02 mm (20 micron) layer height. You will however need quite some 3D printing experience for this.

Micron: A micron (or micrometer) is the term for one millionth of a meter, which is one thousandth of a millimeter (equivalent to roughly 0.000039 inches). Good 3D printers can print at a resolution of as little as 20 microns. For comparison, a human hair is typically 90 microns in diameter.

Model Repositories: Digital libraries or storage places for 3D model files.

Nozzle: The part of the hot end that deposits the melted plastic material.

NURBS (Non-Uniform Rational B-Splines): Mathematical representations of 3D geometry that can accurately describe any shape.

Overhang: Part of a 3D model without any support below it. Parts that protrude at an angle of over 45 degrees are generally considered overhangs.

Photopolymer(s): A polymer that changes its properties when exposed to light. Plastic resins which change their properties when exposed to light. Liquid photopolymers which harden when exposed to UV light are used in the process of stereolithography.

Positioning Precision: Refers to how precisely the nozzle moves to each designated point in a print.

Print Envelope: The total space in which 3D printing can take place, usually expressed in terms of the x, y, and z axes.

Raft: A disposable base which is printed first onto the build surface, with the object being built on top. Provides more adhesion to the build surface and reduces warping. A technique used to prevent warping. A flat layer of support material is printed below the actual 3D part. As the raft is larger than the part it has better adhesion. Once the 3D print is finished, the raft supports are discarded.

Rapid Prototyping (RP): Any process which uses computer controlled machinery to create a prototype of an object.

RepRap: Short for Replicating Rapid Prototyper. A RepRap machine is a 3D printer that can manufacture a significant fraction of its own parts.

Resolution: See Layer Thickness.

Retraction: The process of pulling the filament back from the hot end during printing. If printing a single unit object such as a cup, no retraction is necessary; but if printing a complex object such as a hand, retraction is needed to prevent the molten filament from forming strings between the fingers.

Shell: Also know as outline or outer perimeter, the shell represents the outer wall of a 3D print. Used in plural (“shells“) in conjunction with a number to describe the maximum thickness given to the outer wall. Printing with 4 shells means that your objects’ outer wall will be 4 times your 3D printer nozzle’s diameter (i.e. 4 X 0,4mm = 1,6mm outer wall).

Slicer: Software required to convert a digital 3D model into machine readable code for the 3D printer. The slicer cuts the model into horizontal layers (slices) and generates the toolpaths needed to fill them.

SLA (Stereolithography): An additive manufacturing process which uses a UV laser to cure a photo-reactive resin layer by layer into a solid object.

SLS (Selective Laser Sintering): An additive manufacturing process, which uses a laser to bind photo-sensitive powder materials layer wise into a solid object.

Stepping Motor: A motor capable of very precise small movements, as opposed to the high-speed spinning produced by regular motors. Stepping motors are used to control the position of the print head on each of the x and y axes, while a third stepping motor shuffles the bed down along the z axis after each layer is printed; a fourth stepping motor is used to push the filament through the Bowden cable.

Support Material: 3D models that have large overhangs or gaps between parts require support material to be printed (as it would be impossible to print into thin air). The support material is removed once the 3D print has finished in order to reveal the final print.

Print Speed: The speed at which the print head moves while it is printing. Based on the print speed the amount of plastic that needs to be extruded will be calculated.

Tool Path:  A series of movements made by the hot end of the extruder.

Travel Speed: The speed at which the print head moves while it is not extruding any plastic.

Viscosity: Another name for the resistance of flow of a fluid and often used with reference to extruded thermoplastic material.

X, Y and Z Axis: Taken from traditional geometry, the x and y axes (devised by Rene Descartes in 1637) are the forward/backward, left/right motion of the 3D print head as it prints each layer in two-dimensional space. The z-axis is the vertical component, controlled by a stepper motor that jogs the print bed down when each layer has been printed.