AD ALTA
JOURNAL OF INTERDISCIPLINARY RESEARCH
autonomation that require a bunch of tools to support the house
[25]. In the roof of this house are the objectives to attain: best
quality, lowest cost, shortest lead time, best safety, and high
morale (Liker and Morgan) [26]. To achieve these, companies
must continuously improve, which means to continuously
eliminate waste [27]. There three types of activities: 1) Value-
added activities that are all activities that the client is willing to
pay for; 2) Non-Value added activities or waste that are all the
activities that do not adds value from the client point of view and
that he/she is not willing to pay; 3) Non-Value added activities
are activities that do not adds value but are necessary activities.
Producing with wastes means overburdening people and
machines and the planet, retrieving from it more than is needed.
This is why some authors considered that Lean Production
contributes for better work conditions and better environment
[28], [29] To provide sustainable solutions, Lean have been
associating with important methodologies such as TRIZ [30].
Value concept is the first principle of Lean Thinking principles,
[31]. That is the philosophy behind Lean Production. The other
four principles are Value Stream, Flow, Pull production and
pursuit perfection. This concept of perfection is similar to
Ideality concept reviewed in the previous section (2.2), where
Ideality goes even more further.
3 Development of the ideality equation
3.1 Ideality for processes
In this paper, the goal is to determine an Ideality equation
useable for processes. First, crucial parameters for the state of
the process should be set. In manufacturing processes, we are
mainly focusing on the time of production, quality of production,
and the cost of production. Because Productivity and quality are
not everything, we should also look for safety, ergonomics, and
ecology of the process. These are the six main aspects of each
process. To have a process in a better state we need to have
shorter production time, better quality, less cost, higher safety,
less ergonomics, and environmental impact. These aspects are
inspired by Toyota's house from [26], described above..
Ergonomics and ecology aspects of the process have been added
for the health of workers and the better environmental impact of
the processes.
For final Process’ Ideality, we should consider all of these
aspects and at the same time keep the properties of the original
TRIZ Ideality from equation (1) without changes.
3.2 Ideality equation for processes
The easiest way of how to formulate an Ideality equation for
processes including all six key aspects is to put all six aspects
into the original equation (1). In case that we would try to only
decide which of parameters is beneficial and which is harmful,
the result will be that all parameters could be defined as harmful
for the process because we want to have it in ideal on zero levels
(no time, no defects, no costs, no safety risks, no ergonomics or
ecology impact). Every aspect should be defined as a positive
and negative part and these values should be put into equation
(1), then a theoretical Process’ Ideality equation appears.
∑
∑
∑
∑
∑
∑
∑
∑
∑
∑
∑
∑
+
+
+
+
+
+
+
+
+
+
=
ECO
ERG
S
C
Q
T
ECO
ERG
S
C
Q
T
l
theoretica
H
H
H
H
H
H
B
B
B
B
B
B
PI
(3)
Where B’s are representing beneficial parts, H’s representing
harmful parts. Index T is for time, Q for quality, C for Costs, S
for safety, ERG for ergonomics, and ECO for ecology.
The problem with equation (3) is the same as with equations (1)
and (2), it works only in theory. In practice, each aspect, time,
quality, costs, etc., have a different dimension, and these
dimensions could not be added together. One way to solve this
problem is to recalculate every aspect into costs. That is
possible, time for production can be represented by costs, the
cost for defects can be also calculated, even safety, ergonomics,
and ecology could be determined as costs. This recalculation to
costs could be hard but mainly it is time-consuming. That is why
a different approach was chosen.
To reach dimensionless of the result, the equation must be
divided into a sum of partial Ideality for each aspect.
∑
=
=
6
1
i
i
pPI
PI
(4)
Where PI is overall Process’ Ideality and pPI
i
ECO
ERG
S
C
Q
T
pPI
pPI
pPI
pPI
pPI
pPI
PI
+
+
+
+
+
=
representing
partial Ideality for all six aspects (time, quality, costs, safety,
ergonomics, and ecology). In longer form equation (4) looks like
this
(5)
Partial Ideality should be determined for each process’ parameter
(time, quality, costs, safety, ergonomics, and ecology). Partial
Ideality equation should look like
∑
∑
=
=
=
m
k
k
n
j
j
i
H
B
pPI
1
1
(6)
Where index i represents aspects as time, quality, costs, safety,
ergonomics, and ecology of the process, n is a number of
benefits for aspect i, j is specific benefit, m is a number of harms
for aspect i, and k is specific harm. For calculation of Ideality of
each parameter, we need to determine the beneficial and harmful
part of the parameter. The numerators and denominators for each
partial equation should have the same dimension, so the result
will be dimensionless.
3.3 Partial Process’ Ideality for time
A beneficial part of time connected to the process could be time
spend on Value Added activities (VA time). On the other side,
harmful time is time spent for the rest of the time or we can say
on Non-Value Added activities (NVA time). Partial Process’
Ideality equation for time is then
∑
∑
=
time
NVA
time
VA
pPI
T
(7)
Where pPI
T
is Partial Process’ Ideality for time. The ideal state
of the process from the perspective of time is that we do not
spend any time but the process outcome is done. Formulation
near to this ideal state is that all time spent in production is
productive and only value-adding activities are made. In other
words, more time is spent on productive activities and less on
unproductive ones, the use of time is more ideal. NVA time
contains activities without value, i.e., waste activities and also
activities without value but necessary ones (as machine settings,
maintenance, etc.).
3.4 Partial Process’ Ideality for quality
The quality of the process could be represented by a number of
good and bad pieces. Good pieces (OK pcs.) are beneficial and
defects (NOK pcs.) are harmful. From that the Partial Process’
Ideality for quality (pPI
Q
∑
∑
=
.
.
pcs
NOK
pcs
OK
pPI
Q
) is
(8)
The ideal state of the process from a quality point of view is that
no defects are made, and only good parts are produced. The next
harmful part of quality could be also considered a number of
defect opportunities. This metric could give better information
about defect possibilities of the process which goes deeper and
closer to the quality root cause than only the count of good and
bad pieces.
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