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JOURNAL OF INTERDISCIPLINARY RESEARCH
process’ improvement could be chosen. Process’ Ideality has
advantages that include the main parameters of the process,
decisions based on Process’ Ideality are based on six process’
parameters. The main difference is that instead of focusing only
on technical parameters of the process as time, and quality,
Process’ Ideality also includes parameters as costs, safety,
ergonomics, and ecology.
4.2 Application to a case study
A case study for a demonstration of the use of the Process’
Ideality calculation was made. The process of glass-metal
assemblies was chosen. Improvement of this process is described
in [32]. Glass and metal parts and assemblies are packed in three
ways which are depending on the properties of parts, mainly on
weight and size. For this demonstration, only one path of the
process is considered. For each step, an average time for activity
its cost, quality, safety, ergonomics, and ecology risk should be
determined. Parameters of the process and its steps are described
in the table Tab. 2 below. Symbol X in the table represents that
its impossible or very hard to determinate a parameter for a
specific activity in the process, so there must be a different way
of how to calculate or determine desired values for that column.
If we do not know a parameter value for steps, values can be
determined for the whole process. For example, we do not need
to sum ecology risks from all steps if we do not know these
values we can determine an overall ecology risk for the whole
process instead.
activity
category
time
[min]
number of
defects
costs
[CZK]
safety
risk
ergonomics
risk
ecology
risk
1
walk for parts
NVA
0.5
X
1.67
0.04
0.04
X
2
bring it to workplace
NVA
0.5
X
1.67
0.04
0.04
X
3
walk for box
NVA
1.0
X
3.33
0.04
0.04
X
4
bring it back
NVA
1.0
X
3.33
0.04
0.04
X
5
walk for packing mat.
NVA
1.0
X
3.33
0.04
0.04
X
6
bring it back
NVA
0.5
X
1.67
0.04
0.04
X
7
built the box
NVA
0.5
X
1.67
0.04
0.04
X
8
tape the box
NVA
0.5
X
1.67
0.04
0.04
X
9
packing
VA
5.5
X
18.33
0.08
0.6
X
10
documentation
NVA
0.5
X
1.67
OK
OK
X
11
close the box / tape it
NVA
0.5
X
1.67
0.04
0.04
X
12
bring it to strapping machine
NVA
0.5
X
1.67
0.04
0.4
X
13
strapping
NVA
1
X
3.33
0.04
OK
X
14
writing on box
NVA
0.5
X
1.67
OK
0.04
X
15
bring it to weighing-machine
NVA
0.5
X
1.67
0.04
0.4
X
16
weighing
NVA
1.0
X
3.33
OK
0.04
X
17
waiting for printing
NVA
1.0
X
3.33
OK
OK
X
18
stick information
NVA
2.0
X
6.67
OK
OK
X
19
bring the package on palette
NVA
2.0
X
6.67
0.04
0.04
X
20
fix it together
NVA
5.0
X
16.67
0.08
0.04
X
Tab. 2:
When information about the process is collected, the calculation
of partial Idealities can begin. For calculation, equations for
partial Process’ Ideality from above are used. It is very hard to
determine quality for every step, for our purposes a relative
number of defects is enough. In our case, there are
approximately 4 defects per 100 produced parts. Most appeared
defect is broken glass part during packing or manipulation in
process. From that, we can calculate Partial Process’ Ideality for
quality, where the number of OK pieces is 4, and the number of
NOK pieces is then 96. For the determination of process’ profits,
average profit per package is needed. This value was determined
as 20 [CZK] per package. Steps in this process have a relatively
small environmental impact, but a number of several wastes
should be included. In this case, Partial Process’ Ideality for
ecology is calculated for the whole process, wherein the
numerator is 1 (as one whole process), and in the denominator is
overall ecology risk from wastes, which was for this case
determined as 0.04. Ecology risk of the process is quite low
because in the process recyclable materials are used, and residual
material could be used again and waste material is sorted for
recycling. Results of Partials Process’ Idealities for the original
state are summarized in Table 4.
Original state of the packing process
After the improvement, a new table with information about the
process should be done. The process was mainly improved by
the shortening of material and people flows [33]. As a result, the
layout of the workshop was re-designed and several other
improvements were applied. After improvement, there is much
shorter walking, most of the materials are stored on the packing
workshop, so several movements and walks were eliminated. For
better ergonomics packing tables were bought. These tables
allow to set optimal packing height for each worker, and it also
allows to transport packages to the next operation. When the
process is improved, the collection of information about the new
state of the process could be done again. The procedure of
collecting the information should be the same as for the original
state. Several activities were eliminated and other activities had
shorter lead time, or its ergonomics risk is lower
Collected information about the improved process is summed in
Table 3.
activity
category
time
[min]
number of
defects
costs
[CZK]
safety
risk
ergonomics
risk
ecology
risk
1
walk for parts
NVA
0.5
X
1.67
0.04
0.04
X
2
bring it to workplace
NVA
0.5
X
1.67
0.04
0.04
X
3
built the box
NVA
0.5
X
1.67
0.04
0.04
X
4
tape the box
NVA
0.5
X
1.67
0.04
0.04
X
5
packing
VA
5.5
X
18.33
0.08
0.08
X
6
documentation
NVA
0.5
X
1.67
OK
OK
X
7
close the box / tape it
NVA
0.5
X
1.67
0.04
0.04
X
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