Page 70 - ASBIRES-2017_Preceedings

Wijayarathna & Appuhamy
2 LITERATURE REVIEW
There are limited empirical studies
which have been done in this area and they
are outlined below in detail. Chandrakar and
Kumar (2015) discussed about reduction of
breakdowns in food processing plants
through failure analysis and investigates the
causes of downtime by performing root
cause analysis. By this analysis and methods
the root causes of the breakdowns were
identified.
This in turn helped to develop and
improve a preventive maintenance checklist
for the machine and help increase in
productivity due to downtime reduction,
decrease in cost production and reduction of
delayed deliveries due to good knowledge of
production capacity. Kiran, Mathew &
Kuriakose, (2013) conducted a case study in
a manufacturing industry with the aim of
finding out the major breakdowns causing
production losses to the company and to
suggest counter measures by which these
problems can be reduced.
By using cause and effect diagram,
root causes of breakdowns were identified.
Some parallel improvement opportunities
were also identified for the implementation
so as to reduce the downtime. Kumar &
Rudramurthy (2013) proposed a case study
on increasing the availability of a machine,
reducing the down time of a machine,
maximizing production capacity, reducing
the idle time of the machine and improving
new preventive maintenance schedule which
were the main objectives of this research
project.
By this analysis and methods the root
causes of the breakdowns were identified.
Furthermore, it concluded that the
preventive maintenance scheduling helps to
achieve above objectives. The researchers
Verma et al., (2016) conducted a case study
of analysis of breakdown maintenance. This
case study was carried out by following
paint manufacturing unit situated in northern
part of India. The main objective of this
study is to minimize machine breakdown
hours and to enhance the overall availability.
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The data includes operating time of
the machine, down time and number of
failures. Analysis of root cause was
conducted to evaluate the reliability of
machines. Ab-Samat, Jeikumar, Basir,
Harun and Kamaruddin, (2012) conducted a
case study by implementing preventive
maintenance scheduling in order to reduce
the downtime of machines.
This paper investigates that causes of
downtime by performing root cause analysis
and proposed affinity diagram which
highlighted several issues with
implementation of preventive maintenance.
Analysis of the tree diagram was done in
order to generate possible solutions. In this
study machines are separated into critical
and non-critical, each having a different
priority and therefore reduction in downtime
as well as workload on the technicians.
3 METHODOLOGY
The present study carried out in a
Virgin Coconut Oil Expeller Plant in Sri
Lanka. First, the primary data was collected
through direct observation of expeller
machines in this plant over the period of
three months from August to November
2016. Then the time series plots were
drawn to observe variations in number of
working machines in each day of this
specified period. Next, the best fitted
distribution for breakdown times of each
machine was identified and relevant
parameters were estimated using maximum
likelihood method. Individual distribution
identification method in Minitab was used to
identify the distribution. Among the
candidate distributions the best fitted was
selected based on the Anderson Darling
(AD) goodness of fit test. Lower AD value
indicates better fit. Mean downtime of each
machine during study period were calculated
using the fitted distributions.
Since each machine could be moved
into either working or breakdown state two
state Markov chain model was fitted to find
out the probability that each machine
becomes breakdown in long run process.