Why do 3D printers need CNC technology?
Professional control systems have the potential to establish 3D printing as an industrial production method. In terms of hardware, CNC systems such as Rexroth’s MTX deliver the necessary performance, precision and robustness. They offer an array of sophisticated, programmed functions. The machine manufacturer merely has to set the relevant parameters. From a design engineer’s perspective CNC makes it easier to fulfill machine safety standards. In addition, CNC solutions remain available over a long period. In some cases hardware and software support is maintained over several decades.

BigRep claims to be the first company to use CNC. What are your competitors doing?
Increasingly, 3D printer manufacturers are adopting CNC technology. As at the beginning of the electronically controlled machine tool era, manufacturers have tended to develop their own control hardware, which is then programmed “in-house”. CNC solutions significantly reduce the input of time and effort. 3D printing has progressed beyond the prototype stage and will soon form an integral part of the digital workflow in the value chain.

Is G-code now the standard language for additive manufacturing?
In Cartesian applications G-code is currently the established standard for moving to predefined positions. This can change, however. It is conceivable that “point clouds” derived from CAD software will be sent directly to the printer control units. Modern CNC systems already offer sufficient processing capacity.

How important is the data format for the automation process from the CAD program to the printer?
STL is the de facto standard format. But data formats are just a small element in a seamless digital workflow. In the factory of the future all the process stations – including AM machines – will function flexibly as modules in rapidly adaptable production lines. A key factor will be the interplay of CAD, slicer software, simu-lation environments, control systems and quality assurance. To this end automation specialists, machine manufacturers and end users need to agree on common standards. The discussions about OPC UA are promising and it appears very likely that OPC UA will become the worldwide standard for machine-to-machine communication.

Automation standards for additive manufacturing have yet to be defined. What is the current status of the discussion?
Compared with other production processes, 3D printing still involves a significant manual input. It is now necessary to develop an integrated understanding of the entire process – from initial data creation to final quality assurance. The decision in favour of standardized CNC solutions with open interfaces is an important step – not least because it directly defines the automation stan-dards. Rexroth’s MTX solution supports all the current real-time Ethernet protocols, as well as the future IoT standard “OPC UA”.

How long will it take until data flows to 3D printers are as problem-free as in the case of machine tools?
Technologies and tools already exist for coordinating process parameters and motion and controlling additional automation stations. In addition, software solutions such as Rexroth’s Open Core Interface enable machine manufacturers to deploy functions programmed in high-level languages (parallel to SPS) – e.g. CAD, simulation environments, industrial image processing and IT integration. This will create the basis for end-to-end data flows and a fully automated 3D printing process.

In your estimation, how large is the market for the automation of additive manufacturing?
The estimates vary widely, but a figure in the region of €20 billion seems realistic. The faster we establish standards, the faster the potential market will grow. The deployment of robots is a definite possibility. With the aid of CNC and motion control systems they can be easily integrated, thanks to the built-in robot functionality. A further possibility is to equip these upstream and downstream stations with cabinet-free power transmission and control technology and to integrate them via real-time cross communication.