Innovation Lab: Session 1

Overview of the Nomad 883 Desktop Milling Machine in Library Innovation Lab

In this lesson, we'll take a look at the basic process of CNC milling, and introduce you to some terminology you will need to know to understand how milling machines work. We'll teach you the basic parts of the Nomad 883 Desktop Milling Machine that we have at the Earl K. Long Library. We'll show you how to load and unload material, change the end mills, and get you started using Carbide Create and Carbide Motion software. 

What is CNC Milling?

A computer numerical control (CNC) milling machine is a mill that uses computer code to understand where to make cuts. Like all milling machines, a CNC mill produces a final piece by carving away from a block of material versus adding layers of material to a blank slate.

CNC MillingTerminology

Axis – Direction of movement. On a three-axis machine: X (left-right), Y (front-back) & Z (up-down).

Ball End (Ball Nose) – A cutting tool that has a rounded cutting arc tip, where the arc diameter is equal to the cutting diameter. This tool is typically used for cutting flutes, 3D toolpaths, pocket trays, cutting board juice grooves, and much more.

Bed – The work surface top of your machine that a waste board or material is placed on to be machined.

CNC – Stands for computer numerical control and is a machine that the movement is controlled by a computer using numerical (g-code) commands.

Collet – A metal collar that holds the cutting tool within a spindle nut.

Depth Per Pass – The depth of which the tool will cut on each pass in the z-axis. If the depth per pass is set less than the material thickness, it will cut multiple passes until it reaches the final cut depth specified for that toolpath.

Down Cut Bit – A cutting tool whose edges carve downward on the face of the material. This reduces the potential for tear-out on the top of the material, but requires a slower feed-rate because the down flutes push the chips of material into the cut, rather than clearing them out.

Drag Knife – A cutting tool that holds a razor or knife blade used to cut and inscribe material. Used with spindle or router motors turned off, the drag knife freely spins as it follows the direction of the toolpath. (Cut2D Pro, VCarve Pro, and Aspire can create toolpaths for this with the Drag Knife Gadget.)

Drill – A pointed tool that is rotated to cut holes in the material. Normal drill bits usually require slower RMP spindle speeds to work properly.

Gantry – The frame structure that straddles the bed and carries the spindle. It moves on guide rails along the length of the bed and is driven by stepper or servo drive motors.

G-Code – A machine language that uses axis points and commands which the machine uses to move and perform functions. This code is auto generated from your toolpaths and must be saved with a post processor specific to your machine. (Think of g-code as the directions from a map route at which your machine will move and follow precisely.)

Hold-down – A clamp or other such device used to firmly hold a workpiece or fixture to the table. Includes cams, clamps, double-sided tape, vacuum table, vacuum pods and others.

Home Position – Mechanical position where the X, Y, and Z axis will reference from. Generally set from a g-code command with the help of limit or homing switches.

Jig – A production work holding device that locates the workpiece and guides the cutting tool (see fixture). Used primarily for accuracy and in production machining.

Spindle – A rotating motor that holds tools and is used to machine parts. (Sometimes substituted for a router.)

Spindle Speed – Rotational speed of cutting tool (RPM).

Waste Board - Holds the material to be cut to the bed of the milling machine.

Thanks to Learn Your CNC - https://www.learnyourcnc.com/blog/common-used-cnc-terms-and-definitions for the above terminology.