5-axis CNC machining principle

2019-12-20 16:13

What is 5-axis CNC machining?

In the simplest terms, 5-axis machining involves using the CNC to move parts or cutting tools simultaneously on five different axes. This allows very complex parts to be machined, which is why 5-axis is particularly popular in aerospace applications. However, several factors have contributed to the widespread adoption of 5-axis machining. These include: Facilitate single-set processing (sometimes called "integrated molding") to reduce delivery time and increase efficiency The ability to avoid collision with the tool holder by tilting the cutting tool or table, which also allows better access to part geometry Tilt the tool / table to maintain optimal cutting position and constant chip load, which extends tool life and cycle time


What is the axis in 5 axes?

We all know stories about Newton and Apple, but there are similar stories about mathematician and philosopher Rene Descartes.

Descartes was lying on the bed (because neither a mathematician nor a philosopher would do this) when he noticed a fly humming around his room. He realized that he could use only three numbers (represented by the variables X, Y, and Z) to describe the position of the flies in the three-dimensional space of the room.

This is the Cartesian coordinate system, which has been in use for more than three centuries since Cartesian death. Therefore, X, Y, and Z cover 3 of the 5 axes in 5-axis machining.

What about the other two?

Imagine a Cartesian flight in flight. Not only can its position be described as a point in three-dimensional space, but its direction can also be described. As you spin, imagine the flies rolling in a plane that tilts. Its scrolling is represented by the fourth axis A: the rotation axis around X.

Following the plane's simile, the pitch angle of the fly is represented by the fifth axis B: the rotation axis around the Y axis.

The astute reader will no doubt deduce that the sixth axis C rotates around the Z axis. In our example, this is the yaw of the fly.


5-axis configuration

The specific configuration of a 5-axis machine determines which of the three rotary axes it uses.

For example, trunnion machines operate on the A-axis (rotate around the X-axis) and C-axis (rotate on the Z-axis), while rotary-rotary machines operate on the B-axis. (Rotate around Y axis) and C axis (rotate around Z axis).

How many axes do you need?

You may have seen references to machining centers that offer seven, nine or even eleven axes. Although it seems difficult to imagine many other axes, the interpretation of this staggered geometry is actually very simple.


5 axis vs 3 + 2 axis

It is important to distinguish between 5 axis machining and 3 + 2 axis machining. The former (also known as continuous or simultaneous 5-axis machining) involves continuously adjusting the cutting tool along all five axes so that the tip remains optimally perpendicular to the part.

In contrast, the latter (also known as 5-face or position 5-axis machining) involves performing a 3-axis program in which the cutting tool is locked at an angle determined by two rotary axes. Machining that involves reorienting the tool along the axis of rotation between cuts is called "5-axis indexing", although it still counts as 3 + 2.

Compared with 5-axis indexing, the main advantage of continuous 5-axis machining is speed, because the latter requires stopping and starting between each tool reorientation, while the former does not.

However, you should be able to produce the same results regardless of whether you use continuous 5 or index 5 axes.


5-axis machining and 3D printing

3D printing (or additive manufacturing) is a hot topic in manufacturing today, especially when compared to subtractive manufacturing processes such as 5-axis machining.

Although the two approaches are sometimes suggested to compete with each other-stubborn 3D printing fans believe that the technology will soon disrupt the entire manufacturing industry, a more modest view sees additive and subtractive manufacturing as complementary processes.