Having different software languages can create a communication barrier between robots and the CNC machines they assist. Digital factories can be transformed once the two are synced, and technology is bridging the gap to make it happen. 

As Industry 4.0 revolutionizes the manufacturing world, robots can be increasingly seen working alongsideCNC machines - but only so well. The controllers used by robotics manufacturers rarely coincide with the software that makes CNC machines run, so a fully synchronized operation can be very difficult to achieve. The result is untapped potential in automated manufacturing, as robot-CNC machine interfaces work with less productivity than they could otherwise obtain. 

Researchers are developing new systems to help robots and machines speak the same language, and they're reaching tremendous productivity gains in the process. Advanced control algorithms, digital twin modeling, and a number of other technologies are harmonizing robots and CNC machines, leading to a seamlessly integrated digital factory floor. 

The Problem: Code and Communication

To understand the difficulties of bringing robots together with CNC machines, it's important to know how CNC machines work first. CNC machines perform their subtractive manufacturing processes by taking computer-generated files and converting them into programmable tool paths which their robotic arms may follow. They may do this by grinding, milling, drilling, turning, or lathing.

There are three types of CNC software programs:

• Computer-aided design (CAD), which engineers use to create dimensioned designs of their parts.
• Computer-aided manufacturing (CAM), which translates the CAD files into g-code that the CNC software can read.
• Computer-aided engineering (CAE), which is used for production planning, analysis under operating conditions, and diagnosis for repairs.

Each of these CNC software programs is well-established, and many software packages even incorporate all three into one seamless platform. The problem for robot-CNC interfaces is that the g-code created by most CAM programs is specific to CNC machines only. It is therefore not compatible with the code controllers that robotics manufacturers use as they build their bots. 

Because robotics controllers must be programmed differently (and with more difficulty) than CNC machines, operators would have to know how to adjust both the g-code of CNC machines and that of their robots to synchronize the two. 

That is not feasible, so robots must often be programmed to work in a subordinate role to CNC machines rather than as equal partners. This modular role play is less efficient than a fully integrated system could provide, meaning that productivity is not as great as it could be.

The Solution: Access and Algorithms

One of the reasons that robotics software is incompatible with CNC machines is that robotics control algorithms are less precise. This is because they are typically optimized according to speed so they can move efficiently along unchanging pathways. 

The control algorithms for CNC machines are optimized not only for motion across multiple degrees of freedom but also for parameters like machining rate and damping. This makes them much more precise. If their control algorithms can be integrated into existing robotics controllers, programmers will be able to bring their robotics and CNC machine suite under one software roof. They can also make their robots precise enough for hybrid processing. 

Researchers at Siemens focusing on factory digitization have built in a suite of robotics add-ons for their CNC programming software. As long as operators have access to the electronics and mechanics of their robots, they can implement CNC g-code into robotics controllers. Some robotics manufacturers only enable access to integrated control electronics. However, the digital interface created at Siemens allows CNC programmers to install code from a library meant to bring robotics controllers up to the CNC task. 

By gaining access to robotics control algorithms and installing more advanced CNC controls, robot-CNC machine assemblies can speak the same language — and work together more efficiently.

The Result: Partnership and Productivity

With robots now on the same page as the CNC machines they assist, the two can work together in hybrid processing methods. For example, a part that requires polishing may initially be milled by a CNC machine. Then, it will be removed and finished by a robot equipped for the job. As the robot is polishing the first piece, the CNC machine could begin milling a second piece, achieving a much higher rate of production. 

In this way, robots that are integrated into CNC machining processes can go from achieving menial tasks like workpiece insertion and removal to carrying out parts of the manufacturing process. The team at Siemens reports productivity gains of up to 10% when using this synchronized manufacturing method — a game-changer when improvements of a few percentage points are coveted. 

The Future

Digital factories can create a seamless manufacturing environment when CAE software is used to generate digital twins that plan out every step of the factory floor. And the harmony between robots and CNC machines is expected only to rise. 

As it does, we can expect manufacturers to become more agile, resilient, and productive than ever -- and the robot-CNC unity will help make it happen.