5-axis CNC machining operates on a simple principle: Start from a chunk of any material, whether its marble, titanium, iron, or carbon fiber, and remove the unwanted parts from it until the desired shape or object is all you have left. This process is often called subtractive manufacturing.
But before we go ahead and explore the full scope of 5-axis machining and what’s involved, we need to understand what 5-axis CNC machining is, how it affects the industry, the advantages it offers, and a whole bunch of other ideas listed below.
- What is 5-axis CNC machining
- A Basic History of 5-axis CNC
- 5-Axis Machining vs 3D Printing
- Advantages of 5-axis Machining
- Disadvantages of 5-axis CNC Machines
- Types of 5 axis CNC Machine
- Conclusion
What is 5-axis CNC Machining
5-axis CNC machines are a step above the regular 3-axis machines which operate only 3 primary axes, X, Y, and Z. 5-axis CNC is built in such a way that they’re able to move a cutting tool in five different axes at the same time. These additional two axes is a game-changer in the industry and allow for a multidirectional approach in surface machining.
With this technology, there’s really no barrier to the parts and shapes you can work on, being that the tool can move along 5-axes (directions); the X, Y, and Z axes, as well as rotate on the A and B axes. Simply put, a workpiece can be processed by a cutting tool from five sides in a single operation without any need to reposition the workpiece.
With 5-axis CNC, industrial machine operators can machine complex parts, something that has found a lot of applications in the aerospace, automotive, and medical industries. But machining complex parts isn’t the only reason why CNC has permeated the industry, CNC has become popular due to a need to:
- Reduce clutter by using just a single-setup machine that handles all the machining needs of a manufacturer while also improving efficiency and time to market.
- Improve the life cycle of a tool and achieving the optimum cutting tool position by simply tilting either the table or the tool itself.
- Avoid collision and attain better access to the workpiece.
After making an entrance into the world of manufacturing 5-axis machining has experienced incredible growth and transformed how we perform machining operations, but one thing that continues to confuse a lot of people is an understanding of the axes involved in this machining process.
The Axes of the 5-axis CNC
To understand how a 5-axis machine works, you’ll need to understand how the 1-axis and 3-axis machine function.
For one, the 1-axis machine, a simple pipe bending machine, for example, can only move in one axis, up and down. And a 3-axis machine, take a milling machine, for example, can only move left and right, the x-axis. Forwards and backward, the Y-axis. Up and down, the Z-axis. And this is possible because a 3-axis machine, unlike a 1-axis machine moves its cutting tool along the X, Y, and Z-axis.
But with 5-axis machining, machinists get two extra rotary axes, A and B, alongside the X, Y, and Z axes. The A-axis rotates around the X-axis, the B axis rotates around the Y-axis while the C axis rotates around the Z-axis. When combined, they yield a variation of either AB, AC, and BC.
The beauty of this is that these additional axes allow the cutting tool to approach the workpiece from any direction which drastically reduces the errors that would’ve been encountered with either 3-axis or 1-axis CNC machines.
A Basic History of 5-axis CNC Machining
A lot has happened since the first 5-axis CNC machine was created in 1958. We begin our journey into the history of 5-axis CNC with Golden E. Herrin wrote an in-depth analysis of the history of the 5-axis CNC machine in 1995.
But long before Golden’s analysis was written his first encounter with 5-axis manufacturing was in the very same year it was created, 1958, when the US Air Force awarded a contract to Cincinnati Milacron to build an electric tracing of a 5-axis vertical mill to know if its creation was possible. This was before numerical control became prevalent.
Seeing the achievements 5-axis CNC has made available in the industry today, it’s quite funny to imagine that back then a lot of people thought it was impossible. It was even called the ‘Opium Mill’. But it’s important to note that 5-axis CNC wouldn’t have come this far if not for the improvements in computer technology.
And as computer technology continues to improve, 5-axis CNC would become a lot more efficient and easier to handle than it is today, allowing machinists with little experience to create excellent parts on the CNC while the highly skilled machinists focus on programming the next job.
This increase in efficiency would invariably lead to an increase in the total output of high-quality parts while also leading to a decrease in machine crashes.
The Role of the Post Processor
The Post Processor is a driver specifically built for CNC machines to fill the gap between the 5-axis CNC and the CAM system. Basically translating the computer language to the exact code the 5-axis CNC can understand. And true enough, the entrance of the Post Processor into the world of 5-axis machining has led to a lot of improvements.
It might surprise you to learn that it was just recently, 2019 to be specific, that the US Department of Defense amended the EAR to permit the export of 5-axis CNC machines. The DoD views 5-axis CNC as a threat to national security and so encourages both manufacturers and distributors to install anti-tampering features into each machine, and this feature is triggered in the event a machine gets moved from its original place of installation, or disassembly is attempted.
5-Axis CNC Machining vs 3D Printing
3D printing, additive manufacturing, has opened a whole new world of possibilities in the manufacturing industry, pushing the limits of what we once considered impossible, and with its widespread acceptance, other manufacturing processes like subtractive manufacturing, 5-axis CNC to be specific, might suffer.
Although it might appear, on the surface, that additive manufacturing would completely take over the market, we view both processes as mutually necessary. Additive manufacturing isn’t at the throat of subtractive manufacturing. Additive manufacturing allows for the designing of parts that have never been designed before and subtractive manufacturing allows machinists to produce parts that require a great deal of circularity tolerance.
This way we can combine these two methods by having a 3D printer and a 5-axis CNC continue doing what they do best. Leading to a system where a 5-axis CNC machine works on a 3D printed workpiece to achieve the proper tolerance required.
But this begs the question: Why not combine these two systems instead of using two separate machines?
The answer can be found in powder and chip management. If these two machines were combined, it would be difficult to reclaim any of that powder.
Advantages of 5-axis CNC Machines
The list of advantages offered by 5-axis machines is really long. The definition of true advantage delivered by these machines varies from one machine shop to another. Since 5-axis machines have a lot to offer, here’s a complete list of benefits these machines offer.
Single Setup Machining Saves Time
Besides the clamped section and the base of the workpiece, 5-axis machines allow machinists to work on all the surfaces of the material. And unlike the 3-axis machines where the workpiece has to be manually re-arranged several times to achieve the desired objective, 5-axis CNC only requires one setup to achieve any machining objective. Fewer set-ups mean less space for future mistakes.
With single setup machining, production time is saved, and more work can be done. Also, using reliable CAD software like SolidFace would allow for the quick and efficient designs of parts for the 5-axis CNC to work on.
Complex Design Machining
One thing that really limited the ability of 3-axis machines in handling really difficult designs was the presence of complex shapes and arcs which usually demanded that the machine undergo multiple setups and a host of special fixtures.
But since 5-axis machines can work around the workpiece to achieve the desired geometry without any need for an extra setup or special fixtures, they can conveniently handle complex design machining. A lot of the tools made in CNC shops require machining on all 5-sides, and although 3-axis machines might get it done, 5-axis machines would do it faster and more efficiently.
You might be competent and have all the experience when it comes to handling a 3-axis CNC machine, but some parts just cannot be with the same level of efficiency because they require 5-axes.
Rotational Accuracy
Unlike 3-axis machines where once you remove a workpiece and set it up for each machining session it loses its precise alignment, 5-axis machining improves accuracy by allowing its machinists to complete an operation in only one setup so the precise material alignment isn’t lost and complex designs can be executed with the exact quality demanded.
Faster Material Removal
With 5-axis machining, the cutting tool is held tangential to the surface in need of machining. More material is removed with each pass of the cutting tool. This allows for low cycle times which can go a long way in saving cost because more material is removed each time the tool passes.
Undercutting is made easier because the extra motions make it possible to machine arcs and angles with extra set-ups and special fixtures that could never be achieved previously.
Offers the Best Surface Finishes
With the 4th and 5th axes, you can orient and bring the part closer to the cutting tool, which means that a shorter cutting tool can be used. Shorter cutting tools can attain better surface finish because they are less susceptible to vibration at high cutting speeds.
And although the extra axes would indeed save you time and improve the surface finish of the material, it’d also remove the need for long lead times, something that cannot be avoided with 3-axis machines because they require very small cuts to create the same surface finish that can be offered on a 5-axis machine.
Less Competition
Not every machine shop has access to a 5-axis machine, so by having one you have the unique advantage of offering exceptional service to your customers, something your customers really need and something your competitors cannot offer to them.
Save Money with 5 Axis Machining
We know that what’s more important to machine shop operators, besides producing high-quality materials is saving money. To crown it all, The advantages mentioned above come under the umbrella of saving money for consumers. Putting an exact numerical value on any of these variables is challenging, but any seasoned CNC operator or machinist would be able to see the gains, both directly and in the long run.
Disadvantages of 5-Axis CNC Machining
Obviously, people in the engineering and processing sectors have recognized the benefits and value of 5-axis CNC technology. Having experienced complicated setbacks in the design and manufacture of complex materials, people will switch to 5-axis machining technology. Multi-axis, high speed, strong stiffness, and high strength are the major technological specifications for CNC machines; The market for coordinate numbers is based basically on three to five axes. However, the use of 5-axis machining to do some jobs in the machining industry is not as broad as we assume, for the following reasons:
It’s Expensive
On one hand, the cost of buying 5-axis machines and the required software is high, which is far higher than the cost of the normal 3-axis machining center. On the other hand, the computer itself is more difficult to operate than the general equipment. These considerations often contribute directly to the cost of machined 5-axis parts being much higher than ordinary 3-axis machining.
Programming The 5-axis CNC is Difficult
Although the 5-axis machining is distinct from the 3-axis, there are two rotational motions involved in addition to the three linear motions, and the spatial direction of the synthetic movement created is very complex and abstract, which is usually difficult to visualize and to understand.
For example, in order to process the requisite free-form space surface, it is always important to transport several coordinate transformations and complex geometric spatial operations, and often to consider organizing the movement of each axis, to prevent interference, collision, and the sufficient amount of interpolation movement, etc. To ensure precision and surface quality of the machining required, machining precision and surface quality, the programming difficulty is even greater.
High Technical Requirements for the Operator
5-axis machining is a state-of-the-art manufacturing technique and modern equipment includes the use of high-level expertise. From single programming to working machining, the normal 3-axis devices vary. That needs a high technical operator, which often means higher labor costs.
Types of 5-axis CNC Machine
There are many uses where 5-axis machines can save you time and boost your internal operation, but there is no standard approach when it comes to 5-axis machining. 5-axis machines have several configurations that suit the demands of industries. Although it’s worth noting that the configuration of the rotary axes is one of the most distinctive differences among 5-axis machines.
Head/Head 5-axis Machines
In this type of 5-axis machine, both rotary axes on a head/head machine are located in the head. These machines are designed with the 5-axis head on a gantry that travels above a stationary table that holds the workpiece. This allows the head to travel around the part making these machines ideal for manufacturing large parts. Due to their design, these machines typically have limited travel in both the tilt and rotary axes.
Table/Head 5-axis Machines
In this layout, the table occupies one rotary axis, while the head comprises the other. The tilting axis is also in the head but has a small range while the rotary axis is in the table and usually has an infinite range. This design is limited to the size of components it can produce since the element sits on the rotary axis. An advantage of this design over the head/head design, though, is the freedom to rotate the component constantly, without thinking about exceeding a cap.
Table/Table 5-axis Machines
Table/table machines have both rotary axes in the table, and like table/head machines they typically have limited range in the tilting axis and unlimited range in the rotary axis. This configuration normally has the smallest work envelope of the three configurations in this paper. Nevertheless, some table/table machines are equipped with linear motors which make them extremely fast.
Conclusion
In the end, 5-axis machines save time for the customer, and 5-axis machines often save money directly. Improved tool life means that fewer instruments are needed, and improved precision means less chance of costly errors. There are also several other ways 5-axis machines can save you money, including lower floor space needs, improved durability, and spindle use decreased need for expensive fixtures, and lower overall inventory investment.
While a 5-axis computer is definitely an investment, along with the other advantages mentioned, the resulting reduction in expenditures makes it a good option for machine shops.
