This paper investigates the effectiveness of the continuous spindle speed variation (CSSV) technique as a chatter-suppression strategy in the milling process. For this purpose, a two-fold study was carried out: on the one hand, a simulation analysis, and on the other, experimental tests. First, the semidiscretization method has been extended to n-mode systems in any spatial direction and modified to include simulation capabilities concerning spindle speed variation with different waveforms. A new kind of stability map for different amplitude and frequency variations is proposed in order to optimize the parameter selection when machining. Finally, the effectiveness of the CSSV technique is verified through experimental tests.
Research and development organisations (RTOs) are at the heart of innovation systems. They help to connect innovation system actors to foster industrial innovation. Due to this intermediary role, they act as paradigmatic open innovation (OI) actors. In this context, RTOs need to balance their knowledge stocks and flows, while assuring their own innovation capabilities and positively impacting the innovation system they influence. Thus, RTOs need to develop collaboration approaches that support their own performance while increasing their capabilities and not threatening their competitive advantages derived from their knowledge stock. In this study we extend the OI research to research organisations analysing their OI approach and the impact on its own performance, developing a new framework for OI study in RTOs using a partial least squares structural equation modelling (PLS-SEM) approach. The research, based on a sample of Spanish RTOs, arises two substantive conclusions. First, an increased number of collaboration partners (collaboration breadth) and the use of a variety of OI practices have a strong impact on RTOs’ overall performance (scientific, transference, and economic results). Second, RTOs need to foster their aperture and promote an active management to benefit from collaborating partners, whereas managers should pay special attention to questions related to the protection and management of intellectual property when promoting the use of different OI practices. Both results also emphasise the importance of managing firms’ knowledge flows in the implementation of OI in RTOs.
A major issue in micromilling is unpredictable tool life and premature tool failure. The specific acoustic footprint and very small removal rates during machining as well as the use of small diameter cutters makes the detection of tool breakage a very difficult task. Thus, it is essential to develop new tool monitoring systems to increase the process productivity, reduce machining costs, and at the same time improve the precision and quality of machined components. This paper analyses three cost-effective and reliable methods for tool breakage detection: an on-line laser system, an on-line tool-workpiece voltage monitoring system, and a programming solution employing an off-line laser system. In order to verify the capability of these three methods, a series of experiments were conducted on an ultra-precision micromilling machine. This involved the machining of test parts in brass, aluminium, steel, and polymethylmethacryate (PMMA) with cutters from 0.5 mm down to 0.1 mm in diameter. The results of these tests are analysed and the technological capabilities of the three studied monitoring approaches are then compared. In addition, the possibility of developing an integrated solution that combines the capabilities of these three monitoring methods is discussed and conclusions made about the feasibility of such an approach.
The central role of R&D centers in the advancement of technology within industrial enterprises is undeniable and clearly affects their strategies, their competitiveness and their business sustainability. R&D centers assume responsibility for technology recognition, collection, acquisition, development and transition. Among their activities, the efficient choice of emerging technologies in the Technology Management Process is becoming a real challenge. In such heterogeneous scenarios, Multiple Criteria Decision Making (MCDM) models are commonly proposed as an appropriate decision-making approach. Multiple research works address the selection of particular technologies in industrial applications, but very few references can be found related to research institutions, and R&D centers in particular. Therefore, a decision-making model is provided in this study following the MIVES multi criteria method for the assessment of one or more technologies. The model is then applied to two case studies related to the selection process of new technologies at a Spanish R&D Center specialized in manufacturing.
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