Title: The training of suppliers: a linear model for optimising the allocation of available hours

Authors: Francesco Lolli; Rita Gamberini; Mauro Gamberi; Marco Bortolini

Addresses: Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Via Amendola 2, Padiglione Morselli, 42122 Reggio Emilia, Italy ' Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Via Amendola 2, Padiglione Morselli, 42122 Reggio Emilia, Italy ' Department of Management and Engineering, University of Padua, Stradella San Nicola 3, 36100 Vicenza, Italy ' Department of Industrial Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy

Abstract: The cost of quality represents a relevant item in total manufacturing costs. The learning process is incorporated into contemporary models because of its impact on unitary production costs through both autonomous (learning by doing) and induced (learning by means of proactive actions) learning processes. A learning model with time-varying learning rate is proposed in order to establish the relationship between quality improvements and training hours to allocate to suppliers. The performance indicator adopted is the rate of non-conforming units, rather than the more traditional process variance. This enables definition of a novel total cost function, which can be minimised for the best allocation of training hours to suppliers during a single learning cycle. A novel criterion also emerges for the evaluation of suppliers in terms of investment opportunity. Finally, a case study was carried out in order to verify the applicability of this model to real industrial settings.

Keywords: learning curves; LC; cost of quality; CoQ; continuous improvement; non-conforming units.

DOI: 10.1504/IJISE.2018.089133

International Journal of Industrial and Systems Engineering, 2018 Vol.28 No.2, pp.135 - 151

Received: 15 Sep 2015
Accepted: 19 Dec 2015
Published online: 08 Jan 2018 *

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