Christian Brecher

Virtual machine tool

This paper presents current state of Virtual Machine Tool Technology and related ongoing research challenges. The structural analysis of machine tools using Finite Element models and their experimental calibration techniques are presented. The kinematic analysis and optimisation of machine tool elements are discussed with sample examples. The interaction between the control of the feed drives, cutting conditions and machine tool structure is presented. Multi-body dynamic models of the machine, which allow integrated simulation of machine kinematics, structural dynamics and control techniques, are discussed. The interaction between the machine tool, controller and cutting process disturbances are discussed with sample examples. The simulation of machining operation and its impact on the dynamics of the machine tool and CNC are elaborated. The paper presents both the summary of current and past research, as well as research challenges in order to realise a fully digitised model of the machine tool.

Integrative Production Technology for High-wage Countries

Manufacturing companies in high-wage countries are increasingly set under pressure in international competition due the lower production costs in low-wage countries. In order to counteract this development, many manufacturing companies respond to this issue by relocating their production facilities. Due to industrial production’s high dependence on other sectors such as the services sector, this trend threatens Europe’s medium and long term prosperity since outsourcing generally leads to subsequent relocation of services as well as of research and development activities (Lau 2005). With over 40% of German employees assigned to the manufacturing sector, production plays a key role in the national economy of Germany. Consequently, relocation of production poses huge risks for the country’s future economic development (Statistisches Bundesamt 2010).

Closed-loop CAPP/CAM/CNC process chain based on STEPand STEP-NC inspection tasks

The object-oriented STEP-NC programming interface supports a bi-directional data exchange between computer-aided manufacturing (CAM) systems and computerized numerical controllers (CNCs), and by that helps to integrate the CNC into the CAx (Computer Aided technologies in general) world. In this context the current paper introduces the integration of measuring technology into the STEP-NC-based process chain, to be able to preserve the results of the manufacturing process in a set of data and feed them back to the planning process. In particular this paper describes the current draft of ISO 14649 part 16 (Data for touch probing based inspection), which allows the integration of inspection tasks into a sequence of machining operations. It gives a short overview of how part 16 fits in with other inspection data exchange standards and draft standards, such as STEP AP219, dimensional measuring interface standard (DMIS), dimensional markup language (DML) and I++DME. Furthermore, a prototype demonstration scenario for the closed-loop process chain is presented, which includes generation and execution of a STEP-NC program and feedback of measured results, achieved by automatically controlled STEP-NC inspection tasks, to the CAM system.

NURBS Based Ultra-Precision Free-Form Machining

The machining of ultra-precision optical components with form tolerances in the sub-micron range requires a close interaction between the machine tool, the process and the procedure for the NC tool path generation. Especially for the optical free-form machining the choice of a data-format for the surface description as well as the calculation of the tool path is crucial for the overall achievable quality of the work piece. This paper presents the layout of a tool path calculation based on the NURBS data format that has been developed at the Fraunhofer IPT. In addition the interfaces and the hardware and software for the realisation of a NURBS based control unit for Fast Tool Servo turning and local corrective polishing operations are described.

Compensation of Thermo-elastic Machine Tool Deformation Based on Control internal Data

Abstract The thermo-elastic behaviour of machine tool structures leads to unwanted displacements at the tool centre point (TCP) and has a significant influence on the machining accuracy. In the past, therefore, numerous direct and indirect compensation methods were developed to reduce and/or compensate the thermo-elastic displacements. The paper describes a new indirect compensation approach which allows the abandonment of all additional sensors with the exception of one environmental temperature sensor. As input control internal data of the feed drives and the main spindle are used exclusively. The rotational speed and motor current values - the latter correlate to the drive torque - represent the thermal load parameters of the machine. A combination of first and second order time delay elements describes the displacement behaviour of the machine resulting from these load parameters. The parameters of the time delay elements are determined by a systematic calibration procedure. The resulting displacements are calculated online and superposed as offset-values for the correction of the respective axis positions. Practical experiments show that with this elementary method a reduction of the thermo-elastic displacements of more than 80 % of the initial value is possible.

Chatter suppression with an active workpiece holder

The productivity of machine tools is often limited due to chatter vibrations caused by relative displacements between the tool and the workpiece. The following article presents the systematic approach of the integration of an active workpiece holder with two high dynamic axes controlled by piezoelectric actuators onto a milling machine. With these additional highly dynamic axes near the tool center point, the active workpiece holder offers possibilities to prevent chatter vibrations.

Integrative Produktionstechnik für Hochlohnländer

Produzierende Unternehmen in Hochlohnlandern werden im internationalen Verdrangungswettbewerb immer starker durch die augenscheinlich im relativen Vergleich niedrigeren Produktionskosten in Niedriglohnlandern unter Druck gesetzt. Um dem entgegenzuwirken, reagiert eine grose Anzahl produzierender Unternehmen mit einer Verlagerung der Produktionsstatten. Auf Grund der starken Abhangigkeit weiterer Wirtschaftsbereiche (wie beispielsweise der Dienstleistungsbranche) von der industriellen Produktion, gefahrdet dieser Trend mittel- und langfristig den Wohlstand in Europa. (Lau 2005) Produktionsverlagerungen fuhren in der Regel auch zu nachfolgenden Verlagerungen von Dienstleistungs-, aber auch von Forschungs- und Entwicklungstatigkeiten. Da uber 40 % der sozialversicherungspflichtigen Erwerbstatigen in Deutschland dem produzierenden Gewerbe zugerechnet werden, nimmt die Produktion eine Schlusselrolle ein und ihre Abwanderung birgt immense Risiken fur die Entwicklung der Volkswirtschaft des Landes. (Statistisches Bundesamt 2010)

Limits for controller settings with electric linear direct drives

Abstract In considerations of machine tool feed axes directly driven by linear motors, the machine structure has been assumed to be ideal stiff up to now. The reason is the lack of mechanical transfer elements (ball screw for instance) which create the first dominant natural drive frequency. Raising the controller settings with electric linear direct drives with intent to improve control behavior, mechanical oscillations occur. Thus, the mechanical structure itself represents the oscillatory system. In fact, even high natural frequencies can be stimulated due to the stiff anchoring of the linear motor with the high control bandwidth. In this paper the complex interactions between control and mechanical structure are theoretically derived and verified by measurements and investigations on a test bench.

Industrial Internet of Things

This book develops the core system science needed to enable the development of a complex industrial internet of things/manufacturing cyber-physical systems (IIoT/M-CPS). Gathering contributions from leading experts in the field with years of experience in advancing manufacturing, it fosters a research community committed to advancing research and education in IIoT/M-CPS and to translating applicable science and technology into engineering practice. Presenting the current state of IIoT and the concept of cybermanufacturing, this book is at the nexus of research advances from the engineering and computer and information science domains. Readers will acquire the core system science needed to transform to cybermanufacturing that spans the full spectrum from ideation to physical realization.

Industrial Internet of Things: Cybermanufacturing Systems

The Internet of Things (IoT) is an information network of physical objects (sensors, machines, cars, buildings, and other items) that allows interaction and cooperation of these objects to reach common goals [2]. While the IoT affects among others transportation, healthcare, or smart homes, the Industrial Internet of Things (IIoT) refers in particular to industrial environments. In this context Cyber Manufacturing Systems (CMS) evolved as a significant term. This opening chapter gives a brief introduction of the development of IIoT introducing also the Digital Factory and cyber-physical systems. Furthermore, the challenges and requirements of IIoT and CMS are discussed as well as potentials regarding the application in Industry 4.0 are identified. In this process aspects as economic impact, architectural pattern and infrastructures are taken into account. Besides, also major research initiatives are presented. In addition to that, an orientation to the reader is given in this chapter by providing brief summaries of the chapters published in this book. Hereby, the following research areas are addressed: “Modeling for CPS and CPS”, “Architectural Design Patterns for CMS and IIoT”, “Communication and Networking”, “Artificial Intelligence and Analytics”, and “Evolution of Workforce and Human-Machine-Interaction”. The chapter closes with a discussion about future trends of IIoT and CMS within Industry 4.0.