The Comprehensive Guide to 5-Axis Machining
What is 5-axis machining?
The 5 axis machining industry continues to grow year after year, with a compound annual growth rate of over 6 percent. This is causing more and more people to ask the question ‘What is 5-axis machining?” The most straight forward answer to that question is: “a machine that is able to move a tool or a part on five axes at once.”
For reference, an example of a 1-axis machine would be a drill press, as it is only able to move up and down. Following that same logic, a 3-axis machine can move right to left, forwards and backwards, and up and down. When using a 3-axis machine, users can move a tool along the X and Y axis while using the Z axis to move up and down.
With five axis machining, users get two extra rotary axes and open the door to an infinite number of new machining possibilities. These rotary axes are defined by A, which rotates around the X Axis, B, which rotates around the Y axis and C, which rotates around the Z axis. The combination of additional axes is machine dependent and can come in any variation of AB, AC or BC.
With the additional axes, your cutting tool can approach the part from all directions, enabling undercutting that only would be possible on lower axis machines if the part was re-positioned. This is not only time consuming, it also opens the door for errors that are mitigated when using a 5-axis CNC Machine.
History of 5 Axis Machines
To truly understand five axis machining it is important to know its history. In 1995 Golden E. Herrin wrote an in-depth article outlining the history of 5 axis machining. Although a lot has happened since that time, it provides a comprehensive look at the early days of 5-axis machines.
Surprisingly, 5-axis machining can be traced back prior to numerical control. Herrin cites his first experience with five axis manufacturing in 1958. The United States Air Force awarded Cincinnati Milacron a contract to build and test an electric tracing of a 5-axis vertical mill to determine its feasibility.
This machine was seen by many to be outside the realms of reality, earning it the nickname the “Opium Mill.” 5 axis machining today is however in fact very real, and very effective. This is thanks to advancements in computer hardware and software. These improvements enabled CNC designers the ability to handle five axis requirements at price that made sense.
As CAM systems continue to advance, 5-axis machining becomes both easier and more efficient. With a CAM system, shops can make proven parts on a CNC machine using a less experienced machinist/operator, while the more highly skilled machinist is programming the next job at a computer. Using CAM systems, the total output will increase and the number of machine crashes will decrease, resulting in a much higher probability of producing quality parts.
The development of the Post Processor has further enabled the advancement of 5 axis machining. A post processor can be seen as a specific ‘driver’ that is unique to a CNC machine. The Post Processor or “Post” bridges the gap between your CAM system and your five axis CNC Machine, translating to the exact g-code dialect.
An interesting fact of 5-axis machine history is that the US Department of defense listed 5-axis machines on their commodity control list. The Department of Defense viewed 5 axis CNC Machines as advanced technology, important to national security. It was actually not until 2009 that the Bureau of Industry and Security recommended that the United States Government amend the EAR to facilitate the export of five axis simultaneous control mills, mill/turns, and machining centers of certain precision accuracies.
They did however encourage both distributors and producers to develop anti-tampering features into their machines. Our machine partnerMatsuura is an example of a company that followed these guidelines, developing movement detection devices that are triggered if a machine is moved from its place of installation.
Benefits of 5 Axis Machining
The list of benefits that five axis machining offers is a long one. What provides the greatest benefit varies from shop to shop and individual to individual. In keeping with the comprehensiveness of this page we will be providing as complete a list of benefits as possible.
Save time with 5 Axis Machining
A common misconception with 5-axis machining is that it is only effective to use with complex parts that require specialty machining. Although this is a benefit of the additional axes, it is not the only one.
Greater than 60 percent of parts made in CNC shops required machining on 5-sides. Although 3 Axis machining might do the job, 5 axis machining will do it both faster and more efficiently.
Unlike 3 axis machining, the cutting tool stays tangential to the surface you are cutting. More material is removed with each pass of the tool and the requirement for less set-ups result in saved time and saved cost.
Improved Surface Finish
5 axis capabilities on contoured geometry result in an improved surface finish. Five axis machining allows the parts orientation to be closer to the cutting cool. The fourth and fifth axis let the CNC Machinist use a short cutting tool, that will vibrate less, resulting in an improved surface finish.
An additional benefit associated with the improved surface finish ties into the previously listed benefit that the additional axes save you time. Longer lead times are required when machining with a 3-axis machine, as they require very small cuts to create the same surface finish that can be offered on a 5-axis machine.
Cut Complex shapes
You might be the most competent and experienced 3 axis CNC machinist in the world, but some parts require all five axes. This is one of the most widely recognized benefits associated with 5 axis machines. Undercutting is made easy as the additional movements allow for machining arcs and angles that could only be done before with additional set-ups and special fixtures.
Less Competition
Although this is a short one and fairly straight forward, it is important to include it in the list. Not every shop has a 5-axis machine, by having one you have the opportunity to provide your customers something your competitors can’t, which at the end of the day is something everybody wants.
Improved Accuracy and Tool Life
5-axis machining improves accuracy by requiring less set-ups. More set-ups means more room for a potential error. Some jobs can even be done in a single set-up, drastically reducing the risk of error.
With shorter cutting tools comes longer tool life. Five axis machines allow the machine head to be closer to the surface of the cutter. This allows for the use of a higher cutting speed which ultimately leads to a longer tool life as vibration is reduced.
Saves Money with 5 Axis Machining
To end off the list of benefits we are including what is most important to machine shop owners, saving money. All the benefits listed above fall under the umbrella of saving users money. It is difficult to put a exact monetary value on all of these factors, but any experienced CNC Operator or Machinist will be able to see the benefits, both immediate and long term.
In summary, by saving users time, 5 axis machines also directly save money. Improved tool life means less tools are needed, and improved accuracy means lower risk of costly mistakes. There are also many other ways 5-axis machines save you money including, reduced floor space requirements, increased flexibility and spindle usage, decreased need for costly fixtures and an overall lower inventory investment.
Although a five axis machine is certainly an investment, the overall decrease in expenses combined with the other benefits listed make it a smart choice for machine shops.
Simultaneous 5-Axis Machining Versus 3+2 Axis Machining
3+2 equals 5, but 3+2 axis machining does not equal 5-axis machining. There are differences between the two that are worth pointing out. In simultaneous five axis machining, all 5 axes are operational at the same time. It is referred to as 3+2 because a 3-axis milling program is performed while the cutting tool remains static in the 4th and 5th axis. It is for this reason that 3+2 axis machining is sometimes referred to as positional five axis machining.
Full 5 axis machining offers benefits that 3+2 do not. These were provided in more detail above, but shorter lead times and increased accuracy are just a few examples. Five axis machining allows for greater possibilities which opening the door to advanced industries like aerospace and defense. The argument for 3+2 axis machines is that some parts are actually performed more efficiently than they would be on a 5 axis machine. What method is best for you is largely determined by the part being machined. 3+2 axis machining doesn’t offer all the benefits that come with full 5 axis machining.
The original and largest draw towards 3+2 axis machining was that it did not require as large of an up front investment as 5 axis machines, therefore shops used it as a transition from 3-axis machining to 5 axis machining. As 5-axis machines become smaller and more affordable this is practice is decreasing.
5-Axis Post Processing and 5 Axis Verification Software
So far we have covered the history of 5-axis machining, answered what 5-axis machining is, gone over the benefits of 5-axis machining, looked over different types of 5 axis machines and provided a comprehensive list of 5 Axis CNC machine builders.
We have touched on the value CAM systems bring, and how without them, 5 axis machining would most likely not be where it is today. It is important to now mention the link between your CAM system and your CNC Machine.
A Post Processor bridges the gap between your CAM system and CNC Machine. The Post Processor takes the cutter location data (CL Data) from the CAM system and converts it to g-code. The Post processor also tells the post processor what g-code dialect to target.
CAMplete TruePath is the universal post processor. TruePath makes it easy to switch between different CAM systems. Unlimited custom G-code formats can be created and applied to any project. Truepath also assists with 5 axis simulation, five axis verification and tool path editing.