eprintid: 213
rev_number: 14
eprint_status: archive
userid: 7
dir: disk0/00/00/02/13
datestamp: 2009-04-28 08:05:53
lastmod: 2015-05-29 19:49:33
status_changed: 2009-04-28 08:05:53
type: report
metadata_visibility: show
item_issues_count: 0
creators_name: Cerdeira, J. Orestes
creators_name: Charters, T.
creators_name: Cruz, M.
creators_name: Freitas, P.
creators_name: Vasconcelos, P.B.
corp_creators: Eng. Rui Russo (ForEver Procalçado)
title: Report on "Scheduling in a factory"
ispublished: pub
subjects: retail
studygroups: esgi65
companyname: ForEver Procalçado
full_text_status: public
abstract: In order to carry out their orders of shoe soles, this company has a number of tasks T_1, ..., T_n of different lengths to be assigned to groups of machines.
Each group is operated by one worker (two in one case), and an operation cycle corresponds to injection, cooling, and removal of the sole. The time taken at each step varies from one order to another, and when starting a new task a machine needs to be tuned, which takes some extra time. Machines are working in parallel. At the moment the assignment is carried out empirically, and the problem proposed is to optimize the procedure.
problem_statement: During the manufacturing of shoe soles at ForEver, each operator controls a machine which has to be set up every time the production of a new model begins. This is followed by a tuning process, after which production follows a cycle consisting of the functioning of the machine proper, plus the operation by a worker who injects material into the mould, runs the machine and removes the produced sole.
This functioning is of a parallel nature, in the sense that machines operate independently one from another and, for the process considered here, are not part of a larger chain where they would need to wait for the input from another machine, for instance.
The running of this process includes thus the assignment and scheduling
of the different sole models to different groups of machines and operators.

The problem is to decide on a sequence of task assignments satisfying certain objectives related to deadlines, optimization of worker’s time, etc. More precisely, we want to partition the orders into batches ensuring that the above restrictions are met.
date: 2008
citation:   Cerdeira, J. Orestes and Charters, T. and Cruz, M. and Freitas, P. and Vasconcelos, P.B.  (2008) Report on "Scheduling in a factory".  [Study Group Report]     
document_url: http://miis.maths.ox.ac.uk/miis/213/1/foreverreport.pdf