Ing Ind - Inf (Mag.)(ord. 270) - BV (483) MECHANICAL ENGINEERING - INGEGNERIA MECCANICA
097543 - MACHINE TOOLS AND MANUFACTURING SYSTEMS LM
The course provides fundamental knowledge for the selection, management, testing and performance verification of machine tools, considered individually and within a production system, and for the improvement of overall system performance, considering both numerical and experimental techniques.
Laboratory sections are planned to show some of the main concepts and to give the students the opportunity to practise with experimental measurements. Both machine tool builders and users will be involved through demonstrations and industrial visits.
Risultati di apprendimento attesi
In order to pass the exam, the student has to develop the following capabilities:
Knowing and understanding the course topics (DdD1)
Applying and elaborating the learnt concepts for selecting a machine tool/production system and enhancing its performances both during the design and use phase (DdD2, DdD3).
Developing a project work in which non-trivial technological solutions have to be conceived (DdD2, Dd3, DdD5)
Communication skills are requested both during the oral session and for explaining the performed choices in the project work development (DdD4).
DdD: Dublin Descriptors
Architecture and key elements of a machine tool system: machine tool architectures, structures, transmissions, motors, sensors.
Machine tool and vibrational issues. Dynamic analysis of machine that interacts with the metal cutting process: theory of the dynamic instability and related numerical and experimental techniques.Vibration mitigation and control strategies. Experimental evaluation of machine performance (laboratory).
Evaluation of the machine tool energetic efficiency: Scenario description and introduction, ISO 14955 presentation, experimental machine tool energy assessment procedure (laboratory), machine tool energy modelling, energy reduction oriented strategies and process parameter optimization.
Machine tool geometrical tests
Fundamentals of industrial quality control; statistical process control; Shewhart control charts; Type I and II errors; control limits and specification limits.
Capability analysis: performance index; natural tolerance limits; known and unknown distributions; capability indexes; actual capability and potential capability; non-conforming percentage estimation;
In-process monitoring: from product measurements to in-process measures; statistical monitoring of sensor signals; control charting for non-independent data; brief introduction to multivariate analysis and profile monitoring.
Typologies of production systems based on machine tools.
CAPP: fundamentals of Process Planning,CAD/CAM techniques, ISO programming
Methods for systems performance evaluation. Fundamentals of Discrete Events Simulation technique: application on machinery and FMS (Flexible Manufacturing Systems) and tactical planning of simulation experiments.
The knowledge of the following topics is suggested:
Manufacturing basics and in particular machining fundamentals: milling operations, turning operations, cutting force, torque, power computation. Capability of defining a manufacturing cycle for a generic workpiece.
Dynamics of mechanical systems: multi degree of freedom (MDOF) dynamics. Eigenvalue-Eigenvector analysis. Modal approach. Experimental modal analysis. Transfer Functions.
Digital signal processing: Fast Fourier Transform. Transfer Functions and connected estimators.
Control fundamentals: close loop control. PID controller.
Electrical motor basics: drives and electrical motor modelling
Statistic basics: mean, variance,linear regression, confidence interval Gaussian distribution, Fisher distribution, first type error, second type error.
Knowledge of CAD software.
Modalità di valutazione
A project wok needs to be developed (students will be arranged in groups) applying and elaborating the main course concepts (DdD 2, DdD3, DdD5). The project work is structured in different modules.
In this project the part program for the processing of a specific workpiece (with different features) needs to be defined using a CAD-CAM software. The best machining strategy has to be defined (DdD3, DdD5). The cutting parameters for the machining of each single feature have to be optimized considering even the machine dynamics and the chatter (cutting instability) theory. For this purpose, the measurements performed on a real machine tool will be available. Basically, the minimization of the overall production time and the absence of any undesired vibration must be assured (DdD3, DdD5). Specific indicators that consider the production time and the vibration level will be used to assess the performance. If the workpiece is really manufactured on the machine tool (depending on the machine availability) real data gathered during the process will be used to compute the performance indicators. Penalties connected to geometrical deviation from the requested workpiece or to further tool/insert damage will be considered. The workpiece processing is conceived as a challenge between the groups.
In the project an estimation of the energy consumption, after having developed a proper energy model, for processing one or more features has to be carried out. (DdD2, DdD3)
A detailed configuration of the manufacturing systems needs to be defined (DdD1, DdD2, DdD3).
A project report containing the explanation of all the performed choices and the main final considerations (DdD1, DdD3, DdD4) needs to be prepared and submitted. The project globally accounts for 15/30.
Additional points will be delivered to the group that manufactures the workpiece with the better key performance indicator. Additional points will be delivered to the group that produces the workpiece first.
This marking approach tries to award the group that is capable of finding the better solution to a given problem and/or the capability to reply fast to the requests (DdD3, DdD5). This mimics what the companies that deal with manufacturing and with machine tools are forced to do for being competitive on the market.
Note: All the required experimental tests and the workpiece processing will be performed by the course staff.
An oral session on all the course topics (DdD1, DdD4) has to be carried out. During the oral section the discussion of the project work is typically done (DdD4).
The oral session accounts for 15/30.
Lecture NotesAltintas, Yusuf, Manufacturing automation : metal cutting mechanics, machine tool vibrations, and CNC design, Editore: Cambridge : Cambridge University Press, Anno edizione: 2012, ISBN: 05-211-7247-0
D. A. Dornfeld, Precision manufacturing, Editore: Dae-Eun Lee, Anno edizione: 2008, ISBN: 0-387-32467-4
Tayfur Altiok ; Benjamin Melamed, Simulation modeling and analysis with Arena, Editore: Academic Press, USA, Anno edizione: 2007, ISBN: 978-0-12-370523-5
Law, Averill M., Simulation modeling and analysis, Editore: McGraw-Hill, Anno edizione: 2014, ISBN: 978-00-7340-132-4
Douglas C. Montgomery, Introduction to statistical quality control, Editore: Wiley, Anno edizione: 2013
Fortunato Grimaldi, CNC : macchine utensili a controllo numerico : strutture, tecnologie, programmi, lavorazioni , Editore: Hoepli, Anno edizione: 1998, ISBN: 88-203-2487-3
International StandardsAltintas; Budak, Analytical prediction of stability lobes in milling, Editore: CIRP ANNALS-MANUFACTURING TECHNOLOGY, Anno edizione: 1995, Fascicolo: 44(1):357-362
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Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese