RESEARCH PAPERS
FACULTY OF MATERIALS SCIENCE AND TECHNOLOGY IN TRNAVA
SLOVAK UNIVERSITY OF TECHNOLOGY IN BRATISLAVA
2012
Special Number
EQUIPMENT CATEGORIZATION AS A BASIS TO IMPROVE
THE ORGANIZATION OF MAINTENANCE
Juraj DRAHŇOVSKÝ1
Abstract
Each enterprise must worry about its technical equipment. There are many concepts and
strategies to improve the management of the maintenance, e. g. TPM, RBI, LCC, CBM, RCM
etc. However, the basis for each one of these systems should be the equipment categorization.
The purpose of categorization is to classify equipments according to the type of risk
associated with their main function. This allows to focus attention on the parameters and the
criteria used to assign the degree of risk when the equipment fails and to determine the
proper method of maintenance.
Key words
Categorization, Maintenance Goals, Equipment, Maintenance Strategy, Solution Map
Introduction
Maintenance of equipments is one of the most important components of the management
of production services. The goal of the maintenance is to ensure that the realised investments
would be able to create sufficient profit during their useful life. The important aspects of the
competitiveness of the companies are reliability improvement, safety, as well as reducing the
costs throughout the period of their technological usability.
But this improvement is necessary to do systematically. First of all, the company must
regularly evaluate how the individual equipments are involved in the economic results of the
company and classify them into categories according to how this equipments are important.
The general principles for the categorization of machinery and equipments are (1):
a machine or equipment is put into the category that best describes its function type of
construction, the nature of the operation, the useful life, percentage of serviceability, etc.
1
Ing. Juraj Drahňovský, PhD. - Slovak University of Technology, Faculty of Materials Science and Technology,
Institute of Industrial Engineering, Management and Quality, Paulínska 16, 917 24 Trnava, Slovak Republic
juraj.drahnovsky@stuba.sk
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any classification of the machine or equipment to the category covers not only the
machine or device that is completely made up, but also such a machine, which is pretty
incomplete or unfinished,
if it is determined that the machine or the equipment can be classified into two or more
categories, then the category with most exact specification has priority over the categories
with a general specification,
if the machine, equipment, or production line consists of a different components, then the
machine will be classify according to the component which gives it a decisive character
and line will be classify according to the machines, which give it a decisive character.
Category determination
Category determination according to the dominant influence
Each object, system, subsystem, or the machine can be included in categories depending
which component of the production process has a dominant influence on, e. g.:
safety,
environment,
production,
and others.
The objectives of the maintenance for the above categories may be as follows (Table 1):
THE OBJECTIVES OF THE MAINTENANCE
Equipment Category
Objects that enhance safety
and respond to danger.
Objects that are a potential source of a fire,
or a potential source of personal injury.
Objects that have a direct impact on the
quality and capacity of production.
Other objects that do not have a direct
negative impact on the environment,
security, or production.
Table 1
Objectives
Permanent emergency of the equipment,
must be in operation as required.
The minimum number of failures, risk of
developing a failure must be low.
Emergency based on analysis of the direct
and indirect costs.
Minimum direct costs.
Category determination according to the cost
Parameter that was chosen to determine the significance of any category must reflect the
overall objectives of category (1):
category Safety/Environment: cost for safety, cost of removing the consequences of
the breakdowns,
category Production: cost to repairs, cost of lost production, cost of logistics,
category Others: cost to repairs, cost of logistics.
Category determination according to the effect on the production
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The method according to the effect on the production is another method of the category
determination which is more subjective than method according to the cost. The procedure for
this method is as follows:
In the first step it must be sorted out the equipment into the categories Safety,
Environment, Production and Others. All equipment to protect the safety (signal or locking
systems) must be included on the top of the list of significance. For category Production we
calculate the direct cost of equipment repair, and indirect costs arising from the loss of
production, then their sum shall be determined by the relative importance of production
equipments. For category Others we calculate cost including the price of labor and logistics
cost, and accordingly we assign significance (1).
The strategy for selecting the types of maintenance
An interesting concept of strategic decisions about the type of maintenance was presented
at the conference EUROMAINTENANCE. The method „Decision map“ was used as a
technique to solve problems (2).
The concept has been implemented in three steps:
Criterion analysis,
Decision map,
Decision support.
Step 1: Criterion analysis
In this step is performed Pareto analysis of important criteria. Duration of the failure
(lockout duration) as the main matter of the production and frequency of failures as a major
maintenance issue. The aim of this step is to determine how bad are the worst-performing
machines in a given time interval, e. g. one month. Selected worst of both criteria are
classified into subgroups high, medium, low.
Step 2: Decision map
The next step is to place equipment in decision map and accordingly to recommend
decision on the choice of activities. In this map are shown characteristics of worst machines
based on multiple indicators. The aim is to carry out such activities, which will lead to shift
machines in the northwestern section where are low failure time and low failure frequency.
For the upper left section is the rule Operate to Failure (OTF) so use the maintenance
type „fix-after-failure“. The rule for the lowest left section is to improve the skills, because
the number of failures is high, but the duration of the disturbances is low. This means that the
maintenance of these equipments is relatively simple and may be carried out by staff after
training (SLU – Skill Levels Upgrading).
Problematic machines are machines located in the upper right section. Their failures are
not frequent but if they are out of service, it means a big problem because its removal takes a
long time. In that case it is appropriate to analyze the cause of the problem and then to
monitor the status of the machine. There is applied Condition-based Maintenance (CBM).
Machines, which are located in the lower right section, are the worst-performing machines in
both criteria. These are the equipments that are more often in downtime than in normal
operation. Equipments with these characteristics require change of the construction, thus, a
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suitable type of maintenance is reconstruction (modification) – Design Out Maintenance
(DOM) (2).
If some machines are characterized by the middle failure frequency and middle time of
failure then the rule is to apply preventive maintenance – most widely used in the world is
Total Productive Maintenance (TPM) (1).
OTF
TPM
CBM
Legend:
CBM- Condition-based
Maintenance
SLU – Skill Levels Upgrade
TPM
TPM
TPM
OTF – Operate to Failure
DOM – Design Out
Maintenance
SLU
TPM
DOM
TPM – Total Productive
Maintenance
Fig. 1 Decision map (1)
Step 3: Decision support
Subsequently it is determined the cost of each proposed activity or expected savings of
financial means after implementation of these activities. Every decision must definitely be
endorsed and supported by the management company. On average, maintenance costs are in
Western Europe 12-14 % of their gross domestic product. Costs arising from the fact that the
implementation of each repair is associated with expending resources and the loss of a
performance for which is an equipment intended (3).
The research results
In the academic year 2011/12 was made an analysis of machinery and equipment in one
large industrial plant. Machines are divided by sections and for each section was created
categorization of machinery and equipment, which was in force since 2008. These were
subsequently divided in accordance with individual sections. A number of machines was at
each section which were classified according to categories (A, B, C). This classification was
done generally for the entire enterprise.
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Category C (within the entire enterprise) is machinery and equipment, which do not
affect the quality of production and the production itself. Category C represents 22.30 % of
the total approx. 13k machines and equipment. There is applied a Corrective Maintenance.
The category B includes those machines and equipment that are already relevant for the
company (having impact on the quality of the production and operation of production). They
make up the majority of the total number of machines and equipment, which is 48.25 %. The
risk of failure in these machines is acceptable only in respect of a security issue and
emissions. There is intended a Preventive Maintenance for a part of these machines and
equipment. For other machines is not intended any type of maintenance, because for these
machines and equipment is not always possible to identify the same type of maintenance.
Category A is 29.45 % of machinery and equipment which are essential for enterprise.
They affect the quality of the products, operation of production, safety and overall production.
Disturbances of these machines mean high risk of dangerous emissions and the risk of
explosion and therefore threats to staff.
For this category A and part of B machines is not intended any type of maintenance,
neither a strategy for how to deal with failures, prevention, general maintenance work. This
machinery and equipment belonging to these two categories together represent 77.70 % of the
total.
Conclusion
After classifying under different categories and subsequently determining the correct
maintenance strategy was evaluated that on the basis of changes in categorization could be
save about 31.000 €, which represents 5.9 % of total maintenance costs in this industrial plant.
However, there is required a systematic approach to managing maintenance of machinery and
equipment.
References
1.
2.
3.
GRENČÍK, J., STUCHLÝ, V. Organizácia údržby a údržbové systémy. Žilina: EDIS,
2009. 60 s. ISBN 978-80-554-0111-9
MURÍN, A., GRENČÍK, J., STUCHLÝ, V. Organizácia údržby a údržbové systémy.
Žilina: EDIS, 2007. 47 s. ISBN 978-80-8070-667-8
RAKYTA, M. Údržba ako zdroj produktivity. Žilina: Slovenské centrum produktivity,
2002. 200 s. ISBN 80-968324-3-3
Reviewers:
Mazgar Nasipovich Isjanbaev, Prof.
Joanna Rosak Szyrocka MSc. PhD.
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Grading of Course work
BEng (GCU)
Programmes
Outstanding Contribution 90% and above
Excellent Contribution
80%-89%
Very Good Contribution
70%-79%
Good Contribution
60%-69%
Satisfactory Contribution
50%-59%
Fail
40%-49%
Course Work Description:
Maintenance plays a very important role in all kind of
manufacturing industries. Each maintenance has its
characteristics, importance and drawbacks. Performance
of a machine, depends on the type of maintenance
strategies employed on it. Machines used in industries
need proper maintenance because failure of machine may
cause the production loss. Maintenance technique may
vary from one machine to another machine because of the
various conflicting factors like safety, cost, customer
satisfaction etc. Factors affecting machines performance
need to identify and control. Use of inappropriate
maintenance plan may increase the maintenance cost.
Increase in maintenance cost will increase the production
cost. Selection of a maintenance approach to a particular
machine or group of machines is a problem of decision
making and it is always a challenging task for
maintenance Manager/Engineer.
Each student will be assigned with a research paper from
a reputed journal and is expected to critically evaluate
while covering the following task:
a. Problems that has been addressed
b. Maintenance methodology/concepts that has
been adopted
c. Critical analysis on maintenance approach
d. Implementation of statistical tools
e. Conclusion and recommendation made by the
authors.
Task Expected to complete:
Based on the assigned technical paper, prepare a brief report, outlining:
Task
Description
Task Marks
No.
PROBLEM DEFINITION
1
05
(Introduction to the technical paper problem )
SCOPE, VALUE AND FEASIBILITY
2. (The scope of research paper, its value and its importance to feasibility 10
study)
CRITICAL ANALYSIS ON MAINTENACE APPROACH
3. (Critical evaluation, design methodology and approach adopted by the 30
author)
DATA ANALYSIS
4. (Application of relevant statistical tools, other data interpretations,
40
graphs, activity flow charts, Gantt charts etc. used)
CONCLUSION
5. (The conclusion based on the literature review, future work identification 15
and student recommendation for alternate methods)
TOTAL
100
Note: Report must contain maximum 1000 to 1500
words.
Weighting of marks awarded for the following
SI. No.
Description
Weightage
1. Presentation, structure and readability 15 %
2. Technical content and relevance
30 %
Explanation of Maintenance Method
3.
40 %
selected
4. Relevant conclusion and recommendations 15 %
Total 100%
Name and Signature of Module leader
Mr. Muhammad Mumtaz Mirza
2017
Date: 07 July
Central Quality Office
Rev:02
1
26th March 2013
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MARKING TEMPLATE
TASK1
DESCRIPTIVE TITLE (max marks 10)
i
Introduction to the problem
ii
TASK 2
i
Detailed explanation
SCOPE, VALUE & FEASIBILITY (max marks 05)
Scope of plan
ii
Importance of the maintenance plan topic
TASK 3
CRITICAL ANALYSIS ON MAINTENACE PLAN (max marks 30)
Design methodology
i
ii
Approach adopted
Type of work
DATA ANALYSIS OF THE PLAN (max marks 40)
TASK 4
i
Use of statistical tools
ji
Disscuss other relevant data
TASK 5
CONCLUSION (max marks 15)
i
Summary of the plan
ji
Future recommendation
Student comments
Total Marks awarded out of 100
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