G-code

G-code is a numerical control programming language consisting of sequential commands that specify machine movements, feed rates and tool functions.

Updated

G-code is a numerical control programming language consisting of sequential commands that specify machine movements, feed rates and tool functions. A line typically names a motion type, target coordinates and a speed, for example a linear move to a point at a given feed rate. The language originates in CNC machining and was adopted by additive manufacturing, where an extra axis value carries the extrusion amount.

In practice

On a construction printer, G-code is the output of either a slicer or a direct toolpath generator, and it is normal to read and edit it by hand when diagnosing a print. Useful things visible in the file include where the machine starts each layer, how the seam moves between layers, and where sharp corners force acceleration limits that a pumped material cannot follow. Material delivery is the main difference from desktop printing: pumps and long hoses respond with a delay, so start and stop commands are frequently offset in time relative to the motion. Dialects vary, and a file written for one machine should not be assumed to be safe on another.

Related terms

  • Slicing — the process that commonly produces a G-code file.
  • Toolpath — the geometric path that G-code encodes as motion commands.
  • Print path continuity — keeping the path unbroken, which reduces start and stop artefacts in the code.

Frequently asked questions

Do construction printers use standard G-code?
Often, but not always in the same dialect. Many construction printers accept G-code, while others use a vendor-specific variant or a robot language such as RAPID or KRL on robotic arms. Commands controlling the pump, the mixer and any nozzle dosing are usually vendor extensions rather than standard codes.

Related

SlicingSlicing is the conversion of a solid digital model into horizontal layers and machine instructions describing how each layer is to be printed.ToolpathA toolpath is the programmed route the print head follows through space, defining the order, direction and speed of every deposited layer.Print path continuityPrint path continuity is the practice of printing each layer as one uninterrupted path, because every stop and restart creates a weak point.Construction AutomationConstruction automation covers prefabrication, robotics, gantries and digital workflows. Why it lags manufacturing and where it actually pays today.