What is a CNC Milling Machine & How Does it Work | Types of CNC Milling Machines


With the increasing precision and sophistication of mechanical products, especially in aerospace, military, marine and high-tech industries, Computer Numerical Control machining center instead of ordinary machines to meet higher requirements. As the most common machining process for CNC parts manufacturing, CNC milling services requires milling machines to complete the operation. What is a CNC milling machine and how does it work? Here CNClathing.com introduces the definition, functions, types and more details of CNC mills.

What is a CNC Milling Machine or CNC Mill?

A CNC (Computer Numerical Control) milling machine or CNC mill is the computerized controlled machine features drilling and cutting tools for completing the milling process. Milling is a manufacturing method using a rotating cylindrical cutting tool to remove materials from the workpiece and create a wide collection of CNC milled parts with different shapes, slots, holes, and dimensions, this is what is a CNC milling machine used for. There are various constructions of CNC mills. Although different types of CNC milling machines differ in composition, there are many similar aspects. CNC milling machine is usually composed of shaft, worktable, spindle, frame, CNC controller, coolant, lubrication system, power tie rod, housing, axis, etc.

How Does a CNC Milling Machine Work?

Before running the CNC program, secure the workpiece to the worktable of the CNC milling machine, and mount the cutting tools on the spindle. When the machine is prepared, the operator starts to run the program and initiate the CNC milling process with the machine. Based on the types of milling machine and milling parts application, CNC milling machines will rotate the milling cutters with up to thousands of RPM, to execute different operations: feed the workpiece into the stationary rotating tool slowly, or move the tool across the stationary workpiece, or move both the tool and workpiece in relation to each other. On the CNC milling machines, a milling cutter can move along multiple axes and rotate in varying directions, which realizes various complex operations to produce diverse milled parts according to the CAD design.

Different Types of CNC Milling Machines

CNC mills are often classified by the number of axes on which they can operate or spindle directions.

1. Vertical Mill

A vertical mill or milling machine’s spindle axis is vertically oriented, which means the cutting tools on the spindle will shape the materials vertically, and the cutters move while the workpiece remains stationary, the machines can cut into the part easily. There are two basic types of vertical mills

– Turret mill: the spindle is stationary, the worktable that holds the material moves horizontally or vertically to complete the cutting

– Bed mill: the spindle is positioned on the vertical axis, allows for up and down moving, which combines with the horizontal movement of the worktable to performs the milling process.


2. Horizontal Mill

A horizontal mill works almost the same as vertical mills, as the name implies, the cutters on horizontal mills are mounted on a horizontal spindle. The cutting tools of horizontal machines have good support from the arbor and get a larger cross-sectional area than the vertical mill, which allows fast material removal speed, especially from grooves and slots.


3. 3-axis mill

On the 3-axis milling machines, the workpieces remain stationary while the cutting tools move along 3 axes to execute the operations for CNC milling parts with a variety of shapes, sizes and specifications.


4. 4-axis mill

On the 4-axis milling machine, the structure is generally the same as the 3-axis milling machine, except it’s equipped with a turntable, which can realize more operations.


5. 5-axis mill

5-axis means there are 5 directions in which the milling cutters can move. On the 5-axis milling centers, the cutting tools move along the X, Y and Z linear axes as well as rotates on the A and B axes to be close to the workpiece.