Today you’re going to see how CNC machining has evolved from 3-axis to 9-axis mill machines. We are going to see how the manufacturing sector is benefiting.
We will look at;
CNC Milling and its ability to work with many axes. These are:
- 3-axis CNC machining
- 4-axis CNC machining
- 5-axis CNC machining
- 7-axis CNC machining
- 9-axis CNC machining
Let’s jump right in;
Milling is part of the CNC machining process that involves multi-point rotary cutting tools.
You can take a digital form of a part and produce the physical form using raw materials.
CNC milling has many benefits compared to manual milling. Parts produced are perfect down to the smallest details which are impossible by hand.
The best part of CNC milling is the ability to work on multiple axes. This offers flexibility when you are designing complex parts.
This brings us to the next part;
The spindle moves along the X, Y, and Z linear axes.
It is ideal for 2D and 2.5D geometry machining. You can machine all six sides of a part. But, each side will need a new fixture set- up.
This is more time-consuming and expensive. For each setup, only one side can be machined.
With world-class machining facilities, you can get complex and practical shapes.
It is best for planar milled profiles, threaded holes in-line with an axis.
All features on an angle to the coordinate system are impossible with 3-axis machining. This is inclusive of all planar features.
You have two types of angled features you can produce. Understanding the difference between the two is vital in design making.
The machine this feature to one axis. It can be the X, Y, or Z-axis.
Compound angled feature
They machine it on an angle to two axes
3-axis machines cannot machine the two.
4-axis machines have an added rotation around the X-axis.
The spindle moves along the X, Y, and Z-axis and rotates around the A-axis.
Machines are available in several arrangements but mostly in horizontal orientation. The spindle rotates about the Z-axis.
You can mount your workpiece on the X-axis while the fixture goes about the A-axis.
With one setup, you can machine up to 4 sides of a part.
4-axis machining is a cheaper way of making 3-axis machined parts. It reduces costs and eliminates human intervention. This results in minimal human error and high-quality parts.
Since there is no need for a new fixture and re-set-up, machines can work with tight tolerances. It can hold this between distinct features of a part, thus eliminating loss of accuracy.
Types of 4-axis CNC machining:
There are two types,
Indexing and continuous machining.
Index machining involves the rotation of the A-axis with no cutting action. When the correct rotation is achieved, the rotation stops, and cutting resumes. The rotation stops when a brake is applied.
Continuous machining is pretty much self-explanatory. The machine cuts whilst the A-axis is continuously rotating. This method allows you to machine complex arcs like helixes and cam lobes.
With 4-axis machining you can make angled features not possible through 3-axis machining.
4-axis machining allows one-axis rotation in each fixture setup. This implies that angled features remain about the same axes. You will need to put in place extra fixtures.
Most horizontal mills have a 4-axis tombstone arrangement. Horizontal milling is much productive than vertical milling. It is easier to remove chips because of gravity action. The chips fall off rather than going down holes and cavities in the workpiece.
This complex form of CNC milling moves cutting equipment or the workpiece along 4 axes. There are the normal X-Y-Z axes and a rotation about an extra two axes.
There are two types of 5-axis CNC machines, continuous 5-axis machines, and 3+2 machines.
In 3+2 machining, the rotation around the two axes is not simultaneous. The workpiece can rotate at about any angle to the cutting tool. The rotary axes tilt the workpiece in position. Other axes determine the movement of the cutting tool. You can produce complex 3D shapes with 3+2 axis machines.
Continuous 5-axis machines rotate the workpiece about the two axes at the same time. As the workpiece rotates, the cutting tool moves along the X-Y-Z axes.
You can produce complex 3D parts with curved surfaces. This means you can make parts used for injection molding.
Types of 5-axis machines
5-axis machines vary in the arrangement of the rotary axes. There are three different types;
- Head/head. The rotary axes are on the head, the table is fixed and keeps the workpiece in place. These machines have limited movements on the rotary axes because of their design.
- Table/head. One of the rotary axes is on the table while the other on the head. The head has a revolving axis with a limited scope of movement. The rotary shaft on the table does not have a limited scope.
- Table/table. All the rotary axes are on the table. The revolving axis has a limited scope while the rotary axis has full rotation.
Pros of 5-axis machining
5-axis machining gives you high efficiency and precision cutting. You can get a fully machined part with one setup. Less human intervention means less room for error. 5-axis machining is ideal for machining molds for aircraft and automobiles.
- Maintaining an optimal machining position. Machining curved surfaces or features is hard. You need to make sure your workpiece does not collide with the cutting tools. A 5-axis machine with the correct program maintains the correct position when machining. This is done by rotating the table in different directions.
- Timesaving. Products made in CNC shops are machined on 5 sides. Operators need to set up the fixture on each side. With a 5-axis machine, you can machine all the sides with one setup. This reduces the time needed for the finished product.
- Improved accuracy and precision. An added benefit rising from minimal human intervention is accuracy and high precision. Since you do not need to set up the fixture on each side, you reduce room for error.
- Quality surface finishing. 5-axis machining allows you to use short tools. The advantage of this is less vibration leading to quality surface finishes. Curved surfaces also need movement along all five axes.
- Little competition. Not a lot of shops have 5-axis machines. You can use this to your advantage by rising over other competitors.
7-Axis CNC Machining
A 7-axis CNC milling machine will create slender and more detailed parts for you. You have the normal X-Y-Z axes and extra axes defined by;
- Rotation of the part
- The spinning of the tool
- Rotation of the tool head
- Movement of the clamp
7-axis machining has a high degree of movement that gives high precision and accuracy. End products do not need post-fabrication processes.
9-Axis CNC machining
A 9-axis CNC machine is a blend of lathe and 5-axis CNC machining. This means you can CNC turn and CNC mill along planes in one setup. With a 9-axis machine, you drop manual loading and secondary fixtures.
Benefits of Multi-axis Machining
- Multi-axis machining reduces the number of manual adjustments needed. This gives you quality parts with high accuracy.
- Less human labor saves you on costs
- Parts machined have quality surfaces finishes
- You can make complex parts with one setup
- You will look after your tools. The constant movement of the part or table ensures you have the optimal cutting position. This gives your tools a longer lifespan.
Trends In CNC Machining
We are in an era of rapid industrial revolution. New inventions like 9-axis machines promise quality. Better innovations come to make work easier.
Let’s look at the current trends in CNC machining in general.
1. Universal solutions for tooling
Work holding features like vacuum plates and vacuum fixtures are costly. They can deform and you need a custom-made device for your project.
Now we have universal bases which enable you to cut costs by half. We have universal soft jaws that you can customize and use repeatedly.
Pairing vacuum tables and soft jaws give you an efficient way to make complex parts.
2. Adoption of Robotics
Our CNC shops have been using robots for ages. It is only recently that we have integrated collaborative robots (Cobots). They are programmed to work with skill and accuracy along with human beings.
You can teach collaborative robots the intended operation using manual movements.
Its adoption is further accelerated by the emergence of advanced robot visions systems.
Cars like Tesla can recognize other vehicles and pedestrians with robot vision.
Cobots with advanced robot vision systems can perform tasks like humans in a CNC shop.
3. Better workforce training
Manufacturers are including 3D CAD viewers in machine platforms. With screens, you have a guide when setting up and machining. Some have troubleshooting videos included.
This will ensure improved workforce training and fewer operational errors. The result is cost-efficient cycles when manufacturing parts through CNC machining.
It also improves the effectiveness and efficiency of existing workers.
4. Advances in CAD/CAM software
Not long ago was VAD/CAM software ridiculously expensive. Now we have affordable and user-friendly software.
With upgraded CAM/CAD software you have accurate, efficient, and innovative workflows. This software is available for huge and small companies.
We now have automatic tool changers with magazines that can hold more than one hundred tools. Machining centers can many processes with one machine at the same time.
There are machines that are multi-spindle and multi-face cutting enabled.
6. Higher speed and accuracy
Accuracy and speed are the main pillars of CNC machining. They ensure machining efficiency and better quality.
The current CNC systems use a higher-frequency processor with a bit-digit. This offers faster computing speed.
The manufacturing industry will continue to grow. You can see how far we have come. A recent and exciting development that has emerged is a 3D printer and a 5-axis mill in one machine. Think of what you can create with that.
Multi-axis machining offers a vast sea of benefits.
Machines with higher speed and accuracy combined with upgraded CAD/CAM software are the deal.
We can expect better and faster CNC systems in our shops in the future.
Do you think artificial intelligence (AI) can make our systems better?