Environmental Engineering Reference
In-Depth Information
5
A MULTIOBJECTIVE MODEL FOR OPERATION
ALLOCATION AND MATERIAL HANDLING EQUIPMENT
SELECTION IN FMS DESIGN
From both a conceptual as well as a computational point, only a few mathemat-
ical programming models have been proposed for the material handling system
selection problem. Most of the studies have focused on material handling equip-
ment optimization, rather than the entire material handling system. Sujono and
Lashkari (2006) proposed a multiobjective model for selecting MHDs and allo-
cating material handling transactions to them in flexible manufacturing system
(FMS) design. They propose a model that integrates operation allocation (OA)
and MHD selection problem. Their study is an extension of the Paulo et al. (2002)
and Lashkari et al. (2004) studies. The main differences from the previous mod-
els are the new definition of the variables and the introduction of a new variable
that links the selection of a machine to perform manufacturing operation with
the material handling requirements of that operation. In addition, they include all
the costs associated with material handling operations and suboperations, and the
complete restructuring of the constraints that control the selection of the material
handling equipment and their loading, in the objective function. Their model is
presented as follows.
h
∈{
1
,
2
,...,H
}
: major MH operations
h
1
,
2
,..., H
∈{
}
: MH suboperations
e
∈
E
jhh
{
1
,
2
,...,E
}
: set of MH equipment that can handle the combination of MH
operation/suboperation at machine
j
j
∈
J
ips
{
1
,
2
,...,m
}
: set of machines that can perform operation
s
of part type
i
under
process plan
p
Parameters
b
j
: time available on machine
j
OC
ipj
: cost of performing operation
s
of part type
i
under process plan
p
on machine
j
($)
d
i
: demand for part type
i
(units)
SC
j
: setup cost of machine
j
($)
t
ijp
: time for performing operation
s
of part type
i
under process plan
p
on machine
j
T
ij h he
: MH cost of performing the combination of MH
operation/suboperation for part type
i
on machine
j
using MH
equipment
e
($)
L
e
: time available on MH equipment
e
I
h he
: time for MH equipment
e
to perform the combination of MH
operation/suboperation
W
it
: relative weight of the product variable
t
on part type
i
W
et
: relative weight of the product variable
t
on MH equipment
e
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