Machine tools are becoming increasingly more precise, quicker and better. This will also be demonstrated during the forthcoming AMB, International Exhibition for Metal Working in Stuttgart from 13 to 17 September 2016, which is expected to attract 90,000 visitors. However, the basic principle of the metal cutting machine is changing very little. Several rotatory and linear axes are combined differently in a closed housing. The control units are also not readily accessible. In times of “Industry 4.0”, actually only another term for “networking”, the machine tool must be opened up. What will it look like in future?
Answers to this question are provided by Professor Dr.-Ing. Christian Brecher, one of the Heads of the renowned Machine Tool Laboratory at RWTH Aachen University and holder of the Chair for Machine Tools.
Professor Brecher, how must the machine tool of the future change for Industry 4.0?
In our opinion, two aspects are crucial: digitalisation or virtualisation of machine tools and their networking. In the first case engineering will be substantially optimised both through meaningful models of mechanical – i.e. static, dynamic and thermal behaviour – and control technology behaviour (e.g. the drive train or control models). The objective here is to simulate the subsequent machine as far as the process and detect challenges at an early stage. Networking will have more of an effect on the following operating phase. Future machine tools must contain semantic interfaces in order to provide, for example, process data in high resolution for more in-depth analyses, if possible in real time, or be functionally integrated in networked systems.
What effect will increasing automation of processes, especially through robots, have on the design of a machine tool?
Automated production cells already exist in tool construction and mouldmaking for example. However, we have identified major challenges relating to cost-effective operation of these cells (robots, machine tools, bearings) in multi-variant small series – i.e. the typical product range of small and medium-sized enterprises (SMUs). Processes often cannot come on stream in parallel with production time, or the expertise required in this case is not available. To date, there have only been a few approaches to define a functionally extensive interface between a machine tool and a robot that can be integrated into the CAD/CAM-NC chain or the RC chain. This becomes very exciting when we consider flexible automation, e.g. by means of collaborative robotics. We also see great potential here for SMUs and small series.
We are currently establishing a working party which will examine this question both on the research side and during direct industrial cooperation.
What has actually become of the concept of hexapods, i.e. a completely new design of machine tools, for which a great future was once predicted?
Due to various reasons, the concept of parallel kinematics or hybrid solutions could only be successfully established in a few areas. In addition to the area of handling and installation, there are also machine tools in which the advantages, e.g. the high feasible dynamics of special concepts, are used very successfully. One example is the highly dynamic Ecospeed machine from Dörries Scharmann for highly productive aluminium machining in the aerospace industry. In future, there will certainly also be special concepts for specific applications in the machine tool industry.
Machines are becoming increasingly more complex, young people are thinking in apps – how will machines be operated in future?
The development of new, innovative man-machine concepts has a long history in the Machine Tool Laboratory at RWTH Aachen University. For example, the approach of an action-based operating concept – motivated by modern smartphones – has been successfully validated with multi-modal interfaces, thereby significantly reducing the complexity of current human-machine interfaces. Celos from DMG Mori is pursuing an entirely similar approach in this respect. In the MaxiMMI Project, whose participants include leading machine tool manufacturers and suppliers, we are also currently observing the integration of new operating devices such as smart watches, tablets or multimedia glasses in the machine tool environment. Although these approaches offer great potential, they should not be pursued just for their own sake, but should always create a realistic practical application.
Energy efficiency has also been a recurring topic in the machine tool industry for some years. What is the situation at present?
The topic area of energy efficiency is still the subject of current research funding tenders. Whereas we were initially able to design the main units, e.g. spindles, more efficiently after taking account of physical models, more emphasis is now placed on auxiliary units and intelligent thermal management as a whole. Current activities in the Machine Tool Laboratory involve reducing non-productive warm-up times in order to also switch off machines quickly in a flexible way during short breaks in production. From an overall viewpoint, the topic of energy efficiency must be broadly considered in the context of productivity in order to reduce the amount of energy consumption per component.