* Corresponding author. Tel./Fax: #39-6-725-97358. E-mail address: dangelo@disp.uniroma2.it (A. D'Angelo). Int. J. Production Economics 68 (2000) 43}57 Production variability and shop con"guration: An experimental analysis Andrea D'Angelo*, Massimo Gastaldi, Nathan Levialdi  Department of Production, Systems and Computer Science, University of Rome-Tor Vergata, Italy Department of Electrical Engineering, University of L'Aquila, Italy Department of Industrial Engineering, University of Perugia, Italy Received 6 June 1998; accepted 4 February 1999 Abstract The selection of an e$cient shop layout at manufacturing level is a strategic problem, involving considerable immobilisation of "nancial resources. Often the problem is hierarchically solved on several levels. In the present paper we focus on the level of physical system planning and try to de"ne the best shop con"guration in terms of process resources layout (work centres organisation), considering di!erent variability conditions for demand (system input). Data obtained from simulation experiments are being statistically analysed to clear the weak and strong points for each con"guration (job shop, #exible cell shop, #ow shop).  2000 Elsevier Science B.V. All rights reserved. Keywords: Manufacturing systems; Shop layout; Simulation; Performance evaluation; Production variability 1. Introduction The selection of an e$cient productive layout at manufacturing level is a strategic problem, involv- ing considerable immobilisation of "nancial resources. Therefore, planning and design of pro- duction lines include a careful analysis [1], devoted to individuate technological bind that the related production imposes, factors in#uencing strategic system performances and the opportune tool for the selection of the best solution. Often the problem is hierarchically resolved on several levels. In par- ticular, the level of physical system planning re- quires a further distinction of physical components from the control logic. In the present paper we focus on the "rst item: organisation of process resources layout. The manufacturing layout choice passes in fact through the quanti"cation of trade- o! between routing #exibility and set-up savings, i.e., performances of alternative con"gurations showing symmetric advantages and disadvantages. In particular, the analysis goes over a restricted set of alternative choices: job shop, cellular manufac- turing, #ow shop and hybrid systems. The "rst type is a process layout and involves a system resource organisation in isolated work centres, in which machines perform all the same type of processing on parts to be produced. The second type of layout is organised in isolated cells in which only a suit- ably scheduled product family is processed. That is, system resources are allocated at di!erent working departments on the basis of technological binds 0925-5273/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 5 - 5 2 7 3 ( 9 9 ) 0 0 0 1 2 - 2