[Marlin] G000-G001 - Linear Move

📅Update: 2020/09/18

Description

The G0 and G1 commands add a linear move to the queue to be performed after all previous moves are completed. These commands yield control back to the command parser as soon as the move is queued, but they may delay the command parser while awaiting a slot in the queue.

A linear move traces a straight line from one point to another, ensuring that the specified axes will arrive simultaneously at the given coordinates (by linear interpolation). The speed may change over time following an acceleration curve, according to the acceleration and jerk settings of the given axes.

A command like G1 F1000 sets the feedrate for all subsequent moves.

By convention, most G-code generators use G0 for non-extrusion movements (those without the E axis) and G1 for moves that include extrusion. This is meant to allow a kinematic system to, optionally, do a more rapid uninterpolated movement requiring much less calculation.

For Cartesians and Deltas the G0 (rapid linear movement) command is (and must be) a direct alias for G1 (rapid movement). On SCARA machines G0 does a fast non-linear move. Marlin 2.0 introduces an option to maintain a separate default feedrate for G0. Note: Slicers tend to override firmware feedrates!

Notes

• Coordinates are given in millimeters by default. Units may be set to inches by G20.

• In Relative Mode (G91) all coordinates are interpreted as relative, adding onto the previous position.

• A single linear move may generate several smaller moves to the planner due to kinematics and bed leveling compensation. Printing performance can be tuned by adjusting segments-per-second.

Developer Notes

• Developers: Keep using G0 for non-print moves. It makes G-code more adaptable to lasers, engravers, etc.

Usage

G0 [E(pos)] [F(rate)] [X(pos)] [Y(pos)] [Z(pos)]

Parameters

• [E(pos)] The length of filament to feed into the extruder between the start and end point

• [F(rate)] The maximum movement rate of the move between the start and end point. The feedrate set here applies to subsequent moves that omit this parameter.

• [X<pos>] A coordinate on the X axis

• [Y<pos>] A coordinate on the Y axis

• [Z<pos>] A coordinate on the Z axis

Examples

The most basic move sets a feedrate and moves the tool to the given position.

G0 X12   ; move to 12mm on the X axis
G0 F1500 ; set the feedrate to 1500mm/m
G1 X90.6 Y13.8 ; move to 90.6mm on the X axis and 13.8mm on the Y axis

There are some caveats related with feedrates. Consider the following:

G1 F1500 ; set the feedrate to 1500mm/m
G92 E0
G1 X50 Y25.3 E22.4 ; move while extruding

In the above example the feedrate is set to 1500mm/m, then the tool is moved 50mm on the X axis and 25.3mm on the Y axis while extruding 22.4mm of filament between the two points.

G1 F1500
G92 E0
G1 X50 Y25.3 E22.4 F3000

However, in the above example, we set a feedrate of 1500mm/m on line 1 then do the move described above, accelerating to a feedrate of 3000mm/m (if possible). The extrusion will accelerate along with the X and Y movement, so everything stays synchronized.