CNC milling: what is it and how does it work

 

CNC milling involves rotating cutters to cut out the desired shape (or feature) from a block of material (or workpiece). Precision, tight tolerances, and accurate creation are all possible thanks to it.

Computer numerical control (CNC) milling machines in today’s demanding industries produce precision parts. A CNC milling machine can be used in various industries, such as aerospace, automotive, robotics, and medicine.

Here’s what you want to know about used CNC milling. How does milling work? What types of milling exist? What are the advantages? We’re here to help.

CNC milling machines: what are they?

Focus on the basics of milling so you can better understand CNC milling machines. Milling removes portions of a block of material (or workpiece) to make the desired shape (or feature) using rotating cutters.

Machine operators can move the workpiece in different directions against the rotating cutter with conventional milling machines because they feature a moveable tabletop (or clamping device).

The CNC milling machine also uses a rotating cutter to remove materials and produce parts, just like conventional milling machines. They differ in how they carry out these machining operations.

In CNC milling, the rotating cutter is controlled by a computer rather than by hand. In conventional milling, the rotating cutter is controlled by hand. Let’s look more closely at the milling process.

Process of CNC milling

There are three distinct stages to milling.

Stage 1: Make a 2D or 3D CAD Model

To begin the CNC milling process, you must create 3D (or 2D) drawings of the part using software such as Autodesk Inventor, Fusion 360, or SolidWorks. Your dimensions and tolerances can be specified using computer-aided design (CAD) or computer-aided manufacturing (CAM) tools.

Stage 2: CAD Model to CNC Program Conversion

Using the CAM software mentioned in stage #1, export your CAD model into a CNC-compatible file. 3D CAD models can be converted into G-code programs using CAM tools.

As a result, the G-code automates all the steps in the fabrication process. So as cutting sequences, tool paths, machine tool speeds, and workpiece movements.

Stage 3: Setup and execute the CNC milling operation

This stage aims to attach your cutting tools to the spindle of the CNC machine, insert your workpiece into the work surface, and download your G-code.

Start the machining program after completing all these steps. Your workpiece will be milled into the desired part by the milling machine.

CNC Milling 3 Common Functions

Face Milling

A face milling operation is probably the most common way to create flat surfaces. Cutting tools are rotated perpendicular to the workpiece surface during this machining operation.

Face milling is done with a face mill cutter, as the name suggests. It is possible to produce your desired surface efficiently in one pass using these cutters since they are equipped with interchangeable cutter inserts.

The face milling process can also help you achieve a higher-quality surface finish than peripheral milling. Compared to peripheral milling, face milling offers you more control over the machining operation, resulting in a smaller amount of material being removed.

2. Plain Milling

In plain milling, sometimes called slab milling, horizontal surfaces are produced by milling. Cutting tools are machined so that their axes are parallel to the surface that is being machined.

To perform cutting operations, machinists use a special cutter with teeth on the perimeter (plain milling cutters).

3. Angular Milling

As with plain milling, a flat surface can also be created with angular milling. Only the setting of the cutting tool differs between these two operations.

An angular milling process involves angular cuts on the surface of the workpiece with an angled cutting tool axis. Using this method, you can create features such as grooves, serrations, and chamfers.