CNC machining involves programming a series of movements through coordinates into a computer program and then allowing the machining tools to cut into a substrate according to the plotted path. It is an efficient system that allows for precise automated machining on large runs. Typical CNC machining originally ran on a 3-axis Cartesian system, with an x-, y-, and z-axis allowing for three-dimensional machining. However, with developments in machining technology and improvements in computing, additional axes were introduced to allow for even tighter machining for more intricate physical geometries.
3-axis into 5-axis
A typical 3-axis machining plot includes an x-, y- and z-axis, accounting for horizontal, vertical and depth movement. This array allows a CNC machine to be programmed according to three axes that encompass a fully three dimensional space. Programmers realized that additional axes could be created to allow the machine a better command of a given area. The five-axis CNC machine was developed to include rX-, rY- and rZ-axes, each of which represents a rotational plot around and parallel to the actual x-, y- and z-axes. These rotational axes allow the tool to tilt from side to side while moving. With these rotational spaces defined, a programmer can enter a much more intricate pattern for a machining tool to follow. Modern 5-axis machines can cut as close as 3 microns, for an almost perfect cut. Suddenly, applications requiring tighter tolerances were possible to machine with fully-automated equipment, a cut to both cost and labor.
With the advent of 5-axis machining, manufacturers could implement the new method in a variety of ways, leading to a diversity of 5-axis machines. There is typically no “standard” make up of 5-axis machines; in fact, many 5-axis CNC machines are designed with a specific application in mind.
Since the invention of 5-axis machining, developers have introduced additional axes to increase functionality, but for more basic automated needs 5-axis CNC machining remains one of the more common CNC arrays.
Using 5-Axes
With five axes of movement possible, the programming needs can look daunting, but there are many basic CAD/CAM programs that can make the process go smoothly. However, simple programming entries are not exclusive when using a 5-axis machine.
One major concern with 5-axis machining concerns the position of the substrate. Because of the degree of movement available with a 5-axis machine, the substrate should be relatively free in space. Many 5-axis machinists will suspend the substrate in order to achieve this physical freedom. When a substrate is relatively free in this manner, the tool has the freedom to move around and cut it from almost any angle, as designed. However, because a 5-axis CNC can operate with a number of different tools, this is not always necessary.
5-Axis Alternatives
Even though 5-axis CNC machining can provide a high level of freedom for tooling projects, it is not always the best choice for a job. Some jobs do not require the full level of axis rotation that 5-axis machining provides, while others require more. Simple jobs that can be performed by either a 3- or 5-axis CNC require thorough scrutiny to decide which of the two machines would be more cost effective to use in the process.
CNC and DIY 3D Printing 
I agree, not all jobs require a 5 axis machine. I machined many jobs on three axis machines with no problem. Having a 5 or 6 axis machine is nice though and may be needed depending on the job. For example if you are doing CNC cutter grinding on tools it is almost impossible to do without a 5 or 6 axis machine. Unless of course you want a lot of additional work and set up using more than one machine. But to grind the complete tool in one set up requires a 5 axis in my oppinion. Milling can be done with a 3 axis for most opperations.
Martin
certain CAD designs demand a 5 or 6 axis for optimal results
A lot of Prototype Machining work can be done with 2 and 3 axis machines.
When i have been involved in 5 axis work , you are right, sometimes you can get away with 3+2 positional 5 axis, but when it comes to Vac form trimmimg, or style line engraving, then you definatly need the full capability of continuos 5 axis movement, but also the confidence that the head will not go into “over rotation” or the machine head will not collide with the part or fixture
I agreed with you, I machined many jobs on three axis machines with no problem. Having a 5 or 6 axis machine is nice though and may be needed depending on the job. For example if you are doing CNC cutter grinding on tools it is almost impossible to do without a 5 or 6 axis machine.
Loved the article i agree with 5 axis not being needed for all jobs.
nice article..all a jobs my bye needed 3 axis and for 5 axis jobs,my bye engineer think about jig and fixture for do it
All jobs may not need 5 axis but it’s nice to have them available.
We use a 5 axis machine at work – it is a rather big one, absolutely necessary for our applications.
BTW, nice article!
5 Axis will be standard in future, 3 axis is just to complicated for many parts I believe!