CNC (computer numerical control) machining is a process in manufacturing where programmed computer software directs the motions of plant machinery and tools.   The application can be used to automate a range of manufacturing techniques such as milling, water jet cutting, and laser cutting materials. Instructions are fed into the CNC machine through a CAD file and transposed into a precise set of sequential instructions. The CNC machine uses these programmed commands to operate automatically without a physical operator. Manufacturers accrue several benefits through the application of CNC machining such as expense reduction, improved speed, better accuracy, and enhanced productivity levels. 

3-Axis Machining

The workpiece is kept stationary, with only the cutting tool having a range of motion, which moves along the three axes to perform milling on the workpiece. The process of machining 2D and 2.5D geometry involves the implementation of 3-axis machines.

As the name suggests, 3-axis machining is only operable on three axes, simplifying the milling process. The material gets removed from the workpiece on these three axes, described by back to front, up and down, and side to side.

The only drawback of the 3-axis milling is that it is not competent in designing angled geometrical features to the X-Y-Z coordinate system, irrespective of the feature's planar structure. 3-axis machining is suitable for performing drillings and threaded holes in-line with an axis or creating planar milled profiles. 

It is possible to machine a component from all six sides using 3-axis machining, but you will need a new fixturing setup for each side, which is an expensive process. However, if you need a single fixture setup, you should machine only one side of the component.

4-Axis Machining

A 4-axis CNC machine operates on the X, Y, and Z axes and another axis of rotation, which is typically around the X-axis. This fourth axis gets referred to as the A-axis.

4-axis milling works similarly to the 3-axis machining process, where a cutting tool extracts material from a workpiece and creates the desired geometry in the machined part. This machining process is budget-friendly; however, it can also be achieved using a 3-axis machine.

The primary distinction between the two is that, unlike 3-axis machining, the 4-axes machining process provides an additional axis of rotation besides the regular 3-rotational axis. A user can conveniently machine four sides of a component for a single fixture setup.

A 4-axis machine does not demand fixture change-overs and comes with the added benefit that you get tighter tolerances held between features on several sides of the component.

4-axis CNC machining gets classified further into two types -

Indexing: This process occurs when the fourth axis of the 4-axis CNC machining performs the rotation while the machine is idle and not extracting any material. 

Continuous: This 4-axis machining process occurs when the machine can simultaneously remove material from the workpiece while the A-axis undergoes rotation. 

5-Axis Machining 

All axes of 4-axis machining, besides another rotational axis, are traversed by the 5-axis machining, which helps achieve sharp precision and refined detailing in the geometry of components.

Several industries demand intricately crafted components to manufacture aerospace machinery, medical tools, car molds, titanium pieces, artificial bones, military stocks, and several others.

You can find the 5th axis of rotation around the Y-axis in the X-Y-Z plane and around the B-axis. The extreme levels of multidimensional rotation and component movement help achieve precision, polished finish, and high delivery speeds. Such precision components are a necessity in industries like aerospace and flight engineering.

With 5-axis machining, you can perform single-step machining, which minimizes lead time and makes it convenient for you to access the part geometry. This machining technique also ensures tool longevity and boosts process efficiency by having the table tilted to perform the precision cutting.