The aim of the thesis is to propose active damping as a potential control strategy for chatter instability in machine tools. The regenerative process theory explains chatter as a closed loop interaction between the structural dynamics and the cutting process. This is considered to be the most dominant reason behind machine tool chatter although other instability causing mechanisms exist. The stability lobe diagram provides a quantitative idea of the limits of stable machining in terms of two physical parameters: the width of contact between tool and the workpiece, called the width of cut and the speed of rotation of the spindle. It is found that the minimum value of the stability limit is proportional to the structural damping ratio for turning operations. This important finding provides the motivation of influencing the structural dynamics by active damping to enhance stability limits of a machining operation. A direct implementation of active damping in an industrial environment may be difficult. So an intermediate step of testing the strategy in a laboratory setup, without conducting real cutting is proposed. Two mechatronic "Hardware in the Loop" simulators for chatter in turning and milling are presented, which simulate regenerative chatter experimentally without conducting real cutting tests. A simple cantilever beam, representing the MDOF dynamics of the machine tool structure constitutes the basic hardware part and the cutting process is simulated in real time on a DSP board. The values of the cutting parameters such as spindle speed and the axial width of cut can be changed on the DSP board and the closed loop interaction between the structure and the cutting process can be led to instability. The demonstrators are then used as test beds to investigate the efficiency of active damping, as a potential chatter stabilization strategy. Active damping is easy to implement, robust and does not require a very detailed model of the structure for proper functioning, provided a collocated sensor and actuator configuration is followed. The idea of active damping is currently being implemented in the industry in various metal cutting machines as part of the European Union funded SMARTOOL project (www.smartool.org), intended to propose smart chatter control technologies in machining operations.

To maximise productivity and reduce scrap in high-value, low-volume production, five-axis machine tool (5A-MT) motion accuracy must be verified quickly and reliably. Numerous metrology instruments have been developed to measure errors arising from geometric imperfections within and between machine tool axes (amongst other sources). One example is the TMBB, which is becoming an increasingly popular instrument to measure both linear and rotary axis errors. This research proposes new TMBB measurement technique to rapidly, accurately and reliably measure all position-independent rotary axis errors in a 5A-MT. In this research two literature reviews have been conducted. The findings informed the subsequent development of a virtual machine tool (VMT). This VMT was used to capture the effects of rotary and linear axis position-independent geometric errors, and apparatus set-up errors on a variety of candidate measurement routines. This new knowledge then informed the design of an experimental methodology to capture specific phenomena that were observed within the VMT on a commercial 5A-MT. Finally, statistical analysis of experimental measurements facilitated a quantification of the repeatability, strengths and limitations of the final testing method concept. The major contribution of this research is the development of a single set-up testing procedure to identify all 5A-MT rotary axis location errors, whilst remaining robust in the presence of set-up and linear axis location errors. Additionally, a novel variance-based sensitivity analysis approach was used to design testing procedures. By considering the effects of extraneous error sources (set-up and linear location) in the design and validation phases, an added robustness was introduced. Furthermore, this research marks the first usage of Monte Carlo uncertainty analysis in conjunction with rotary axis TMBB testing. Experimental evidence has shown that the proposed corrections for set-up and linear axis errors are highly effective and completely indispensable in rotary axis testing of this kind. However, further development of the single set-up method is necessary, as geometric errors cannot always be measured identically at different testing locations. This has highlighted the importance of considering the influences on 5A-MT component errors on testing results, as the machine tool axes cannot necessarily be modelled as straight lines.

The main goal of this thesis is to propose a strategy which can integrate the precision hydrodynamic polishing system with an ordinary CNC machine tool. This integrated CNC machine tool is capable of applying the hydrodynamic polishing process, which is a high-precision machining method, to compensate the form error on a work surface to improve its form precision. With such a compensation capability, a low-cost CNC machine tool may play the function of precision machining as well as an expensive CNC machine tool does. It is hoped that with this function equipped in a CNC machine tool the international competition of the domestic machining industry can be enhanced. The complete integrating scheme is composed of three parts. The first part is the hardware of polishing system, which is required to attach to the CNC machine tool. The second one is the software developed in this thesis. It includes the codes to generate the commands to control the CNC machine tool and the attached polishing system. The final one is coordinating system that is to synchronize the actions of the CNC machine tool and polishing system. It is done by requiring the polishing system to match the actions of machine tool through measuring the configuration of machine tool consistently. Because of the first and third parts, no modification to the machine tool is needed and the requirement to read the internal information of CNC controller is waved. This will significantly reduce the complexity in implementing the integrating job. When properly integrated with the required sensors, the software developed in this thesis can harmonize the actions of the polishing system and machine tool to execute the form error compensation task. The software will automatically generate the commands for the polishing system and machine tool based on the geometric and material data of work. It does not require the user to fully comprehend the function of the CAM software and the details of polishing process. This will obviously reduce the skill requirement of operator and facilitate the use of the integrated system. Since the CNC machine tool only plays the function of offering the three translational motions (in X, Y, and Z directions), the application of this strategy to an ordinary CNC machine tool is straightforward.

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In this thesis we study the influence of corporate governance on product innovation in the machine-tool sector in Italy. The theoretical framework employed in the analysis is part of the Systems of Innovation literature. It can be defined as a "national-technological system of innovation" type of approach as it distinguishes between countries with different systems of corporate governance and between sectors that employ different technologies. The main hypothesis is that variations in national systems of corporate governance can help to explain national patterns of sectoral specialisation. The thesis focuses on the Italian National System of Innovation from the point of view of its corporate governance. The main characteristics of the system are analysed in the first part of the thesis where it is also shown how they can help to explain the Italian industrial specialisation. The study proceeds with an application of the theoretical framework to the analysis of the machine-tool sector, its technology and its historical evolution. A particular focus is put on the decline of the US in the sector during the 1970s and 1980s and the corresponding upsurge of Japan. The final part of the thesis studies the Italian System of Innovation in the machine-tool sector. It highlights that firms are not the only actors in the System and that other stakeholders, such as customers and suppliers, play an important part in the innovation process. It shows also that the system presents some weaknesses, consisting mainly of the lack of financial resources, that need to be resolved. Our final argument, supported by an econometric analysis, is that one of the solutions suggested by the machine-tool builders association, namely a wave of mergers and acquisitions, is not necessarily the best answer. A stronger coordination and cooperation among competing and non-competing firms appears to be the most incisive solution from the point of view of innovation for this sector.

The diploma thesis focuses on a conceptual design of a surface grinding machine. Aim of this work is to analyze current products and create a new design and ergonomic proposal. Result of this work is a concept of a surface grinding machine, that is defined by its progressive form and intuitive operation. The thesis brings a vision and a new solution for a current machine tool design from an ergonomic and technical perspective.

In theoretical part, this master´s thesis deals with vibrations in cutting machine and description of creation of self-excited vibrations theory. In practical part, there is problem of chatter in cutting machine solved with using simulation program Adams and computing program MATLAB. Gradually, Multi body system of cutting machine and model of cutting tool with features flexible body are analyzed. At the end all both models were used to create complex model of the cutting machine .

Rising demand for high productivity of machine tools leads to increase of the dynamics of the machine tool. With higher dynamics of the components is produced a free tool vibr ation that can affect the path accuracy of the feed axis and of the tool. In this thesis are examined various parameters of the feed axis, so that the influence of each parameter could be determined. To determine these factors is in this thesis created a structuralmechanical model of the feed axis by means of the finite element method and this thesis presents a connection of the FE model with a control loop of an axis that allows the theoretical study of the influences on the accuracy of the feed axis. The results show succes sful coupling of the FE model with the control loop. Selected parameters are analyzed in this paper.

Thesis (Ph. D.)--University of Pennsylvania, 1994. / Includes bibliographical references (leaves 245-252) and index.