Computer Numerical Control (CNC) machining is a subtractive manufacturing process that allows manufacturers to create precise and economical high-precision parts. CNC machining uses cutting tools to remove excess raw material from workpieces to create precise finished products from materials such as plastics, metals, and composites. Nowadays, product teams have many multi-axis machining options, from 3-axis to 5-axis, and even 9-axis. However, in this article, we will focus on what 5-axis machining is, is it practical for large-scale details? Does it lead to higher cutting speeds? We will answer these and many other questions below!
Five-axis machining - operation
A 5-axis machine is based on a tool that moves in five different directions: X, Y, and Z, as well as A and B, around which the tool rotates (these are the rotational axes). Using a 5-axis CNC machine allows the operator to approach the part from all directions in one operation, eliminating the need for manual repositioning of the workpiece between operations. 5-axis CNC machining saves time and is ideal for the production of complex precision parts, such as those found in the medical, oil and gas, and aviation industries.
5-axis machines, CNC machining
There are several different types of 5-axis machines that product teams should be familiar with, including indexed 5-axis CNC machines, continuous 5-axis CNC machines, and CNC turning centers. Similar to 3-axis CNC milling, the tool only moves along three axes and is not in continuous contact with the workpiece, as in indexed 5-axis CNC machining. However, the machining table and tool head can automatically rotate in both directions between operations. Indexed 5-axis machining is ideal for producing housings, assembly fixtures, and mounts. It lies between 3-axis CNC milling and continuous 5-axis CNC machining in terms of speed, accuracy, and the ability to handle complex geometries.
In continuous 5-axis CNC machining, the tool and the workpiece can rotate and move simultaneously during operations, saving time and enabling operators to produce complex geometries with organic surfaces. Continuous 5-axis CNC machining provides better surface finish, speed, and dimensional stability, but at the highest unit cost. CNC turning centers are virtually the same as CNC lathes with one exception - they are equipped with CNC milling fixtures. The workpiece is attached to the spindle, which can rotate or remain stationary, while the cutting tool removes material from the workpiece. By combining CNC lathe components with mills, CNC mill-turn centers provide a high level of precision and geometric versatility, making them ideal for producing loose rotationally symmetrical parts, such as camshafts and centrifugal compressors. This type of 5-axis CNC milling machines offer not only greater precision during machining of deeper parts and hardened materials, but also higher productivity and greater machining speeds. However, 5-axis machining is more expensive due to the demand for specialized equipment and skilled labor.
3-Axis Machining vs 5-Axis Machining
The main difference between three-axis and five-axis milling machines is that the object being machined can be processed from three axes of the first machine and five axes of the second one. Both are highly versatile, automated, and repeatable production processes that allow for fast and economical production of precision components. However, you may choose to use one over the other for various reasons.
If you have a limited budget or simply need a cutting plane, a 3-axis machine may be the best choice for you. In addition to being cheaper than 5-axis machines, 3-axis machines are simpler to program, which allows you to save on labor costs with expensive programmers and operators. Moreover, the setup time is shorter for 3-axis machining. If you need to produce deeper parts or parts with complex geometry, using 5-axis machining will be useful. With a 5-axis machine, details can be machined from all directions - without manual rotation. With 5-axis machining, you will achieve higher productivity, greater precision, more freedom of movement, and the ability to produce larger parts faster.
How a 5-axis machine works, CNC machining
Like any other CNC machine, the 5-axis CNC machine relies on computer instructions to control the movement of the cutting tool (and the workpiece) in order to produce the desired part. The 5-axis CNC machining process begins with the designer creating a 3D model (computer-aided design) of the desired part using CAD tools. Then, the mechanics export this CAD model to CAM software (computer-aided manufacturing), which transforms the drawing into a computer program (also known as G code). The G code contains a set of instructions controlling the movement of the tool along linear axes (X, Y, and Z) and the table along rotational axes (A and C) in order to produce the desired part.
5-axis system, CNC machining - where it came from
All thanks to the French philosopher and mathematician Rene Descartes. The story is very similar to Newton's apple. One day, Descartes was lying in bed and noticed a fly. Looking at it, he realized that he could describe its position in the room using three numbers, represented by the variables X, Y, and Z - what we now call the Cartesian coordinate system. Now you might be wondering where the remaining two came from. In addition to describing the fly's position in space, you can also describe its orientation. So, a fly rotating around the X-axis is the fourth axis, and the fifth axis is the fly rotating around the Y-axis. It is also said that there is a sixth axis, which rotates around the Z-axis.
5-axis - possible configurations
The configuration chosen for the 5-axis CNC milling machine determines which of the three rotation axes will be used. There are two main configurations - spindle machines and rotary machines.
A 5-axis CNC milling machine with a spindle utilizes axis A, which rotates around the X-axis, and axis C, which rotates around the Z-axis, while a 5-axis CNC milling machine with tilt/rotation utilizes axis B, which rotates around the Y-axis, and axis C, which rotates around the Z-axis.
The main difference between them is the way the axis of rotation is represented - in the pin style, this is done by moving the table, while in the rotary style of a 5-axis CNC milling machine, this is done by rotating the spindle. Both solutions have their advantages, so which one to use depends on what you want to do. More than half of the parts manufactured using CNC require five-sided machining, which is why more and more manufacturers are deciding to include it in their services. In addition, 5-axis CNC machining has many advantages compared to 3-axis machining, etc., such as:
Single Configuration
5-axis CNC machines allow for a single setup of the workpiece; then the machine handles each machining operation required to create the desired part. This differs greatly from traditional 3-axis machines, which require multiple machine setups to produce complex geometries. The single-station nature of a 5-axis CNC machine enables fast machining of complex parts while simultaneously reducing costs and errors that occur in traditional processes
Shorter cutting tools and better surface finish
The fourth and fifth axis of a 5-axis CNC machine bring the object being machined closer to the tool. This means that shorter cutting tools can be used, which are less prone to vibration and provide a better surface finish.
Higher precision
5-axis CNC machines are significantly more precise than 3-axis machines due to their flexibility of movement, allowing them to produce not only smoother parts, but also parts that are too complex for 3-axis machines. 5-axis CNC machining can be used to produce many parts for which 3-axis machining is simply not suitable.
5-Axis CNC Machining - Application
Due to the performance of 5-axis CNC machining and its ability to produce complex shapes, it can be used to manufacture parts used in various industries. Here are a few examples of industries that benefit from this technology:
- Aeronautics– This industry requires very advanced machines, as the shapes are extremely complex and unique.
- Medicine - 5-axis CNC machining can assist medical device manufacturers in producing devices, implants, and other solutions that must be manufactured with exceptional precision to meet rigorous requirements.
- Military - Another industry that utilizes 5-axis CNC machining for the production of necessary parts. Some possible applications include submarine components, high-performance engine components, turbine and compressor blades, smart weapons, sensors, stealth applications, and, in some cases, nuclear weapons.
- Power equipment - The production of power equipment parts often requires the use of hard-to-process materials. Thanks to 5-axis CNC machining, you can make the entire process easier and more efficient, and the CNC milling of complex elements will be done professionally.