|Politecnico di Torino|
|Academic Year 2014/15|
Product quality design
Master of science-level of the Bologna process in Automotive Engineering - Torino
To enable students to use, in an integrated way, the main available methodological tools in order to control (according to the continuous improvement principles) the design reliability, throughout the product development process, from initial conception to the final experimental verification.
To develop an understanding of customer needs (Quality Function Deployment) and to prevent potential criticalities, identifying priorities according to the product targets.
To provide in-depth knowledge of statistical fundamentals applied to reliability aimed to get an actual operational capability in the discussed applications, such as: Analysis of Variance, Design Of Experiments, Robust Design and sizing of samples for experimental tests related to the final assessment of the reliability targets achievement.
Expected learning outcomes
To become familiar with the setting up criteria and with the main methodological tools useful to focus designs on what really matters for customers, prevent potential criticalities and monitor the reliability targets achievement. To be able to operate according to the points of view of Robust Design and Continuous Improvement.
Prerequisites / Assumed knowledge
Statistics and Basic Informatics elements
1. Quality planning according to customer requirements and product targets (6 hours)
-Cost items for Quality/Reliability and relevant typical trends.
-Voice Of Customer (V.O.C.) and Quality Function Deployment (Q.F.D.).
-Quality measurements in absolute and in relative terms.
-Quality, Reliability, Maintainability, Availability, Durability and Dependability.
2. Applied Statistics elements (12 hours)
-Descriptive statistics: histogram, cumulative curve and frequency density, Pareto’s principle of ‘factor sparsity’, measures of central location and measures of dispersion, normal distribution, prediction of defective percentage.
-Sampling: different ways.
-Probability: conceptual definitions and fundamental relations.
-Automotive applications of the most commonly used statistical distributions (binomial, Poisson, Weibull, exponential, etc.)
-Confidence intervals: finding the best compromise between accuracy, risks and costs.
-Test of a Statistical Hypothesis.
-Goodness of fit of experimental data with a theoretical distribution.
3. Fundamentals of Reliability and Robust Design (6 hours)
-Probabilistic Design (short mention).
-Detailed examination of the Reliability definition and its implications.
-Concept of "Robustness" (Robust Design).
-Taguchi’s Loss Function.
-Series system and parallel system.
-Multi-target optimizations (short mention).
-Reliability Targets deployment
-Typical trends relating to accumulated operating time: R(t) & F(t) functions, hazard rate and "bathtub" curve.
-Main indicators of the reached Reliability level: MTTF, MTBF, Bx=n.
4. Main statistical tools to prevent failures and ensure Reliability (18 hours)
-FMEA (classical and 2nd generation).
-Parts Count Method (source: MIL-STD).
-Worst Case Analysis (WCA).
-Fault Tree Analysis (FTA
-Experimental Design: interactions, full factorial plans and fractional factorial plans, Analysis Of Variance, Analysis Of Means, confounding, pooling, percentage of contributions.
-Experimental Design applied to Robust Design: double optimization and double array.
-Analytical predictions of reliability, also by a Bayesian approach.
5. Criteria and methods of reliability experimental verification (6 hours)
-Accelerated bench tests on components and groups, aimed to verify their Reliability and/or Durability (Success Run).
-Tests on complete vehicles to validate design in terms of performance and reliability (Reliability Growth Testing).
-Possible synergies between reliability and durability tests.
6. Conclusions (4 hours)
-Main reliability milestones throughout the product development process.
-SIX SIGMA approach (short mention).
In order to supply an effective mastery of the discussed rules and models, is provided an illustration of some applications (drawn from industrial practice) able to highlight the benefits of each method, but also the negative effects arising from an incorrect application.
Practical applications are usually discussed immediately after the theory exposure, except that the following ones, which are of special interest: Weibull, FMEA/FTA, Experimental Design/Robust Design.
One aim of the exercises is to show the ease with which, using EXCEL and other appropriate software, we can deal with statistical problems such as: interpolations with either the "parametric" or the "maximum likelihood" methods, sample sizing for estimating averages and proportions, Weibull Chart, etc..
Texts, readings, handouts and other learning resources
The slides presented during lectures and the EXCEL spreadsheets used in exercises are made available by the teacher in the Portale della Didattica website and in a CD.
Other recommended texts for study and consultation:
-Crow E.L., Davis F.A., Maxfield M.W. - Statistics Manual - Dover Publications Inc., New York, 1960.
-AIAG - Truck and Heavy Equipment Reliability Methods Work Group - Reliability Methods Guideline, Automotive Industry Action Group, December 2004.
-Raheja Dev G., Allocco M.- Assurance Technologies Principles and Practices (2nd Edition), Wiley Interscience, John Wiley & Sons, 2006.
-G. Belingardi - Strumenti statistici per la meccanica sperimentale e l’affidabilità - Levrotto e Bella, 1998.
-A.N.F.I.A. - Linee guida per l’applicazione della F.M.E.A. - ANFIA QUALITÀ AQ 009, 2nd Edition, January 2007.
-A.N.F.I.A. - Manuale di Experimental Design - ANFIA QUALITÀ 014, January 1999.
-A.N.F.I.A. - Guida teorico-pratica all'AFFIDABILITÀ: gestione e strumenti operativi lungo tutto il ciclo di vita del prodotto - 1st Edition (2 volumes) - ANFIA Service S.r.l., Turin, July 2012.
Assessment and grading criteria
The examination consists of a written test followed by a final oral test. The written test includes multiple choice questions and application exercises. It allows a preliminary assessment focused on the knowledge acquired by the Student and on his ability to apply it to solve practical problems. If the written test is unsatisfactory, the Student is not admitted to the oral test. The final oral test is aimed to evaluate the level of mastery acquired by the Student on the Course’s topics and refines the previous evaluation, based on the written test, providing a balanced final assessment.
Programma definitivo per l'A.A.2014/15