3D printing definitions: G – L

G

G-code – a standardized machine language that instructs a 3D printer how to move, extrude material, and control temperature during the printing process. Generated by slicing software from a 3D model.

Gantry – the mechanical frame (often XY-based) that holds and moves the extruder or print head in FDM and SLA printers.

Gap fill – a slicing algorithm function that fills small voids between infill or wall structures, improving strength and surface quality.

Ghosting – also known as ringing; wavy distortions on surface walls caused by vibrations during fast movement or sudden direction changes.

Granulate – raw plastic pellets used in large-scale or industrial 3D printers that bypass filament.

H

Heated bed – a temperature-controlled build plate that improves adhesion and reduces warping of thermoplastics like ABS.

High-temperature polymers – engineering-grade plastics like PEEK, PEI (Ultem), and PPSU that require specialized printers to handle extreme processing temperatures.

Homogenization – post-processing or print settings designed to ensure uniform density and material properties throughout a part.

Hygroscopicity – the tendency of materials (especially filaments) to absorb moisture from the air, which can cause bubbling and degradation during printing.

I

Idle temperature – a standby nozzle temperature that avoids full retraction but prevents oozing between print operations.

Infill – the internal structure printed inside a 3D model to provide strength, support, and stability. It is typically defined by a percentage and pattern, affecting part weight and print time.

Interactive support – user-controlled placement of support structures in slicing software for optimized removal and minimal scarring.

Interface layer – the transition zone between support structures and the printed part, designed to ease removal while maintaining stability.

Isotropic properties – when a material has the same strength and behavior in all directions. 3D printed parts often have anisotropic properties.

J

Jitter – small inconsistencies or shakes in printed lines due to loose belts or unstable printer frames.

Jog controls – manual movement commands used to test axes or adjust nozzle/bed position in printer interfaces.

K

Kapton tape – heat-resistant polyimide tape used to cover build plates to improve adhesion, especially for ABS.

Knurling – a textured surface (often in tools or grip zones) that can be replicated in prints for functional or aesthetic purposes.

L

Lattice structure – complex, lightweight internal geometries often generated automatically to reduce weight while maintaining structural integrity.

Layer – a single horizontal cross-section of a 3D printed object, deposited sequentially during the printing process. Layers stack on top of each other to form the final part.

Layer height – the thickness of each individual layer in a 3D print, measured in millimeters or microns. It directly affects surface quality, print speed, and level of detail.

Layer shifting – a defect where layers are offset due to sudden movement issues, usually caused by mechanical slips or stepper motor skips.

Light engine – in resin-based printers (e.g., DLP), the component that projects light to cure photosensitive resin.

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