Glossary

Positions and coordinates

Machine coordinates (MPos) — where the machine is relative to its own origin, established by homing. They do not move when you set a work zero. Everything the machine protects itself with — travel limits, tool-change positions, park positions — is expressed here.

Work coordinates (WPos) — where the machine is relative to your workpiece. This is the coordinate system your programs are written in, and the one you set when you zero.

Work zero — the point on your material that the program treats as X0 Y0 Z0. Usually a corner of the stock, and usually with Z at the top surface.

Work offset — the distance between machine zero and work zero. Setting work zero is really recording this offset.

Homing — the cycle that drives each axis to its limit switch to establish machine zero. Until it has run, the machine does not know where it is. See the homing gate.

Soft limits — boundaries the controller enforces in software, from the travel figures in your machine profile. They only mean something once homed.

Travel — how far each axis can physically move.

Cutting

Feed rate — how fast the tool moves while cutting, usually in mm/min.

Rapid — a non-cutting move at maximum speed. G0. A rapid through material is a broken tool.

Plunge — moving straight down into material. Most cutters do this badly, which is why plunge rate is a separate, slower number.

Spindle speed — how fast the cutter turns, in RPM.

Depth of cut — how much material a pass removes.

Stepover — how far a pass moves sideways from the last one.

Climb / conventional — which way the cutter rotates relative to its direction of travel. Changes finish, load and how the work is pushed.

Tools

Endmill — a cutter that cuts on its sides as well as its tip.

Flute — a cutting edge. More flutes means a smoother finish and less room for chips.

Shank — the plain part of the tool held by the collet.

Collet — the sleeve that grips the shank. Sized for a specific shank diameter — see the tool library.

Toolsetter — a fixed sensor the machine touches the tool against to measure its length, so a tool change does not mean re-zeroing Z.

Touch plate / probe — a plate you touch the tool to in order to find a surface or an edge.

Programs and toolpaths

G-code — the language machines are driven in. A program is a list of moves.

Toolpath — the route one operation takes. A program is toolpaths posted into G-code.

Post / posting — turning toolpaths into a G-code file for a particular controller.

Operation — one machining step: a pocket, a contour, a drilling cycle.

Tool run — a group of operations sharing one cutter, so all the work for a tool happens between two tool changes.

Stock — the material you are cutting from.

Fixture — how the work is held down.

Machines and firmware

Controller — the board that turns G-code into motion.

Grbl — the controller firmware most hobby CNC machines run.

grblHAL — its newer relative, with more axes and more capability. Prime Motion drives both.

$ settings — the controller's own configuration: steps per millimetre, maximum rates, acceleration, soft limits. See Firmware settings.

Alarm — the controller refusing to move because something is wrong: a limit hit, a failed probe, lost position.

Feed hold — a controlled pause that decelerates rather than stopping instantly.

Soft reset — clearing the controller's state and stopping motion.

In this app

Design — a part you are modelling. (Not "project" — a project here is a set of G-code files.)

Project — an ordered set of G-code files that make one part. See Projects.

Machine profile — everything the app knows about your machine: travel, homing corner, spindle, accessories.

Parameter — a named value your model is built from. See Parameters.

Canvas — artwork placed in a sketch to trace over.

Air run — running a program above the material to watch the moves without cutting.

Mesh height map — a grid of probed heights used to follow a surface that is not perfectly flat.