evaluation of downtime in milling system with approach to failure...

International Journal of Engineering & Technology IJET-IJENS Vol:17 No:01 1

173001-2626-IJET-IJENS © February 2017 IJENS

I J E N S

Evaluation of Downtime in Milling System

with Approach to Failure Reporting Analysis

and Corrective Action System

Tri Susanto, Aurino RA Djamaris, Mirsa D. Novianti, Fidya Ayumi

Tri Susanto: Department Of Industrial Engineering, Universities Bakrie, Indonesia ([email protected]) Aurino RA Djamaris: Department of Management, Universities Bakrie, Indonesia ([email protected])

Mirsa D. Novianti: Department of Industrial Engineering, Universities Bakrie, Indonesia. ([email protected])

Fidya Ayu Saomi: Department Of Industrial Engineering, Universities Bakrie, Indonesia. ([email protected])

Abstract— Poor implementation of tracking failure, analysis

root of the problem, and verify the corrective action which takes

place continuously, will increase the failure. Corrective

implementation action which only the failure symptoms handles

and doesn't really fix the root problem of failure. Note that the

Milling System Area is the area most often repeated failure, so

the exact failure identification to prevent any failure that occurs

and preventive actions have to be done so that the machine can

still reliable. Based on Pareto analysis obtained level of downtime

that occurs in the area of the largest Milling System i.e. i.e.

37.5%, caused by damage to the cement mill with the kind of

common problems, such as spilling material on inlet process

prior to grinding mill (grinding). Efforts to address the failure on

the machine with the use of the FRACAS (Failure Reporting,

Analysis and Corrective Action System), which includes the

observation of failures that occur, and then documented the

symptoms of failure that occurs. After verifying that the failure

of the items fail performs failure analysis using the form

FRACAS, looking at the history of similar failure then

determining corrective action based on the results of the analysis.

Index Term— component; failure, corrective action, failure

reporting, downtime.

I. INTRODUCTION Companies in doing business with the use of production

assets is not reliable, then failure in carrying out its functions,

so that the targets set previously not achieved optimally It

would result in operational costs and maintenance costs

become greater than had been planned previously. At the

moment there are not many companies in Indonesia which

gave serious attention in preparing for production planning,

so it takes a good maintenance activities and routine

operational activities taking place at the time to keep the

availability of such assets [1]. The more also occurred at a

cement factory PT X, a less noticed production planning

correctly, tool to document, implement, and associate the

FRACAS as a major element to achieve success in the

program reliability.

Failure to operate the equipment in production with a

recurring right in PT X, then is drawn the conclusion that the

level of analysis of the root of the problem in PT X still less

appropriate. Poor implementation of tracking failure, analysis

of the root of the problem, and verification of corrective

action that keeps happening, would boost failure. The

implementation of the corrective action which only handles

the failure symptoms only and does not really solve the root

problem of failure [2], is also the cause of the failure is often

repetitive. Therefore, the need for comprehensiveness in

defining a formal process for reporting failures and corrective

actions in order to encourage improvement in the field of

reliability, availability, and maintenance [3]

The need for comprehensiveness in the defining failure of

much needed given that the main engine used PT X is a

machine that comes from Switzerland that has been operating

for about 40 years. The length of the machine age are

increasingly encouraged to do a comprehensive system

design, integrative, effective and efficient so that the level of

reliability of the machine. This is not just a process of failure

identification completeness alone but is also required in order

for the preventive actions of the advice company party is

ready to tackle the downtime that may occur and the machine

did not experience downtime is getting worse.

In the Journal's Process-Oriented Development of Failure

Reporting, Analysis and Corrective Action System that

FRACAS is known as a tool to document, implement, and

associate the FRACAS as a major element to achieve success

in the program reliability. Eliminating the main cause of the

problem to increase the reliability of the product/service and

get the satisfaction of customers with timely delivery. On

early improvement, as it is known that implementation and

verification in corrective action more difficult and expensive

especially when the products have entered the age of mature.

II. LITERATURE REVIEW

According to [4], maintenance is an activity that is done

repeatedly with the goal of keeping the equipment always has

the same state conditions first. Maintenance is also done to

keep equipment remain in conditions that can be received by

users. Maintenance is an activity that is done deliberately to a

facility with a specific systematics embraced to achieve a

predetermined result [5]. Essentially, the maintenance is a

human activities conducted to maintain or take care of an

object/hardware so that it can continue to be used.

Referring to the strategy, in this case the repair will be

made after the failure of the equipment/termination or at the

time of the occurrence of severe performance degradation.



I J E N S

This strategy is widely applied in manufacturing industries

before 1950. At this stage, the engine served when needed

major improvement. This concept has weaknesses with the

termination of the operation was not planned before, the

damage repeatedly, the problem of spare parts, repair costs,

waiting time and troubleshooting the higher [6]

Preventive Maintenance

This concept is explaining to do physical examinations over

the equipment to prevent damage and prolong the age of

service equipment within a certain period or duration of the

operation of the machine [7]. During this period, the

maintenance functions implemented and time-based care

activities (Time based Maintenance – TBM) customarily done

Paid (1997) (as cited in [8]). Preventive Maintenance is

carried out on the basis of the estimated probability that

equipment will experience a decrease in performance or

damage at the specified interval. Preventative maintenance

performed includes lubrication, cleaning equipment, spare

part replacement, adjustment and inspection.

Predictive Maintenance

Predictive maintenance is often also referred to as

maintenance based on condition (Condition Based

Maintenance – CBM). In this strategy, the action taken in

response to the treatment condition of certain equipment or

when the equipment experiencing the declining of

performance. Diagnostic techniques are used to measure the

condition of physical equipment such as engine temperature,

noise, vibration, lubrication and corrosion. When one or more

of these indicators reach a predetermined threshold,

maintenance initiatives underway to develop equipment to the

desired conditions. This means that the equipment is removed

from the production line only if there is direct evidence that

there has been noticeable performance deterioration.

Predictive maintenance based on the same principle of

preventative maintenance even though it uses different

criteria to determine a specific maintenance needs. Another

plus is that the need to perform maintenance occurs only

when the need is real, and not after the passage of a certain

period [7].

Corrective Maintenance

Introduced in 1957, in which the concept to avoid equipment

failure equipment reliability improvement being expanded so

that equipment failure can be removed (increased reliability),

and equipment can be easily maintained (maintenance of

equipment upgrade). The main difference between corrective

and preventive maintenance is that the problem should exist

before any corrective action taken [8]. The purpose of

corrective treatment is improving the reliability of the

equipment, the ability of the maintenance, design flaws

(material, shape), equipment undergoing structural reform,

reduce damage and failure, and the aim has been achieved the

condition maintenance-free tools.

Reliability Centred Maintenance (RCM)

The reliability of a product or system to convey the concept

of reliable or the system successfully operates in the absence

of failure. Reliability is also defined as the probability of an

item, be it goods or intermediate goods, which will be used at

the next stage without experiencing failure in a specific time

period. The concept of reliability is a type of engineering

application in creates a risk [4].

On the concept of reliability, reliability concept involves a lot

more, among others, the following:

a. Reliability Prediction or predicted reliability, basically the

type of reliability concepts this is kind of related to the use

of models, the past history of the same product in an

attempt to predict reliability and products in the design

phase. The process can be updated on the next step in the

effort to predict reliability.

b. Reliability assessment or the assessment of reliability, it is

associated with the estimation of reliability based on

actual data, which may be in the form of test data,

operational data, and so on. The system involves

modelling, goodness of fit for a probability distribution,

and related analysis.

c. Reliability optimization covers many areas and related to

the achievement of a suitable trade-off between various

competing objectives such as performance, cost, and so

on.

d. Reliability test design or reliability test design with regard

to the method for obtaining the validity, reliability and

accurate data.

e. Reliability Data Analysis or the reliability of the analysis

can be related to parameter estimation, selection

distributions, and many other aspects.

High cost motivated engineers to find a solution to the

problem of reliability in reducing expenses, increasing the

production quality, timely order delivery by means of

increasing the availability of the equipment, and reduces

problems arising from products that failed and costs are cheap

and easy. In the context of the calculation of financial

management, measurement of reliability in a system or

equipment by calculating the annual fee which will be

removed from the equipment. When assets are used in the

placement of high reliability it will reduce the cost of failure

of equipment. Reliability is often formulated as follows:

(1)

Reliability system with many components is defined as

follows:

R= Rcomp.A + Rcomp.B + …+ Rcomp.N (2)

While the general reliability calculation based on

consideration of mode against early failure, which can be



I J E N S

referred to as figures of early failures (decrease in failure

rates that will come over time) or wear the usage mode (i.e.

the increasing failure over time). The main parameters that

describe the reliability are:

a. Mean Time To/Between Failure i.e. the average distance

between each time failings

b. Mean Time To Repair (MTTR) i.e. an average distance

of time used to make improvements

c. Mean Life to Component i.e., the average age of

component

d. Failure Rate i.e. the average equipment failure at a given

unit of time

E. Maximum Number of Failure i.e. maximum equipment

failure at a specific time

Probability here contains the notion that quantitative in

nature because it usually will be revealed with the quantitative

values is a number in the form of a percentage or a decimal.

The value of reliability is between 0-1, a value of 0 means

very low reliability and component cannot be used. Whereas a

value of 1 indicates high reliability. To determine the

reliability in connection operational required a more specific

definition. The first is a description of a well-defined failure

so it is not confusing and it can be observed. The second is the

identification of the unit of time (in units of the machine

cycles or calendar time).

Weibull distribution

Weibull Distribution the empirical distribution is the most

widely used and most appear on all the characteristics of the

failure of the product due to the third phase includes the

damage that may have occurred in the distribution of damage.

The two parameters used in this distribution are called with

parameter θ scale (scale parameter) and β is referred to as

parameter form (shape parameter). Reliability function

contained in the Weibull distribution [10]:

Reliability Function:

R(t) =

(3)

Ɵ > 0, β>0, and t > 0

In the Weibull distribution to determine the extent of

damage from a data pattern that is formed is a parameter.

Change the values of the parameter form (β) which shows the

rate of damage can be seen in the following table. If the

parameter β is affecting the rate of damage then θ parameter

affects the central values of data.

TABLE I

WEIBUL DISTRIBUTION SHAPE PARAMETER

VALUES

Value Rate Of Damage

0 < β < 1 Deceasing failure rate ( DFR)

β = 1 Constant failure rate (CFR)

Exponential Distribution

1 < β < 2 Increasing failure rate (IFR)

Concave-shaped curves

β =2 Linier Failure Rate (LFR)

Rayleigh Distribution

β > 2 Increasing failure rate (IFR)

Convex-shaped curves

3 < β < 4 Increasing failure rate (IFR)

Symmetrical shaped curve

Normal distribution

Source: Ebelling, 1997.

Reliability with Preventive Maintenance

Increased reliability is preventive maintenance. With

preventive maintenance then the influence of the wear out the

engine or component can be reduced and shows significant

results against the age of the system. Reliability can be

expressed as follows:

Rm(t) = R(t) for 0 ≤ t < T (4)

Rm(t) = R(T).R(t-T) for T ≤ t < 2T (5)

Note:

t = Time

T = Time interval replacement of damage prevention

R(t) = Reliability system without preventive

R(T) = The odds of reliability between time t-T after the

system is restored from the initial conditions at time T

Rm(t) = Reliability of a system with preventive maintenance

In General its equation is:

(6)

n = 1,2,3,…

Description:

N = the number of treatments

Rm(t) = reliability of a system with preventive maintenance

R(T)n = probability reliability up to n time lapse

R(t-nT) = Probability reliability for time t n T from the last

act of preventive maintenance

For constant damage rate



I J E N S

(7)

Based on the formula above prove that the exponential

distribution which has a constant rate of damage, when

carried out preventive maintenance will not produce any

impact. Thus, there is no increase in reliability as expected

because the Rm(t) = R(t). However, if the value is not

constant breakage rate enables preventive maintenance do not

increase the reliability of the equipment. At that point the

solution used is better is the replacement of an engine [11].

Background of FRACAS

Reliability is one of the major dimensions of the quality

performance of a machine or components and can be defined

as the ability of a component or system works in accordance

with its functions based on the needs in accordance with the

time period specified [12]. FRACAS is the management tools

with the aim of identifying and correcting deficiencies that

exist to prevent the problem reoccur [13]; [14] provides

historical data for statistical analysis [12] and improve the

quality and performance of a machine or components.

FRACAS may also be defined as a system that ensures all

failures and damage reported, analysed, and fixed by

corrective actions to prevent a similar failure occurs

repeatedly.

In the past, the U.S. Department of Defence (DOD)

implement the system reliability in the supply of guns with

the standard military official to determine "what" and "how"

it was run. The importance of FRACAS, it has been widely

known in various studies, the FRACAS was known as a tool

to document, implement, and associate the FRACAS as a

major element to achieve success in the program reliability.

Eliminating the main cause of the problem to increase the

reliability of the product/service and get the satisfaction of

customers with timely delivery. More emphasis on the use of

the FRACAS early improvement, as it is known that

implementation and verification in the corrective action more

difficult and expensive especially when the products have

entered the age of mature.

The importance of process failures by using the FRACAS,

because of the needs of the completeness of the

documentation as a guide in defining large problems to

achieve a reliability program running smoothly. In addition,

the effectiveness of this FRACAS in line with program

requirements needed to perform the corrective action which is

composed on ISO 9000 "Quality Management Standards".

Table 2 shows the relationship between ISO 9000 and

FRACAS.

Figure 2 shows that the FRACAS was a closed-loop

system that involves all stakeholders. With the FRACAS

can be guaranteed that the entirety of the data retrieved

efficiently and process analysis of the root of the problem

is obtained in an effective manner.

III. METHODOLOGY

FRACAS Process

The use of the FRACAS is already heavily used in some

industries, for example in the military industry, railways, and

the semiconductor industry. In RAC, mentioning some of the

fundamental characteristics of the FRACAS, i.e.

Record and catch all the failures and problems related to

the components, processes, on the stage of development

and delivery of a product or service

Identify, select, and prioritize the failures and problems

to be analyzed and determined the roots of the problem

Identify, implement and verify corrective actions to

prevent the recurrence of the failure of the root causes or

issues

Providing all personnel with access to all information

about the failure analysis and corrective actions to

support the development of reliability and proactive

decisions to prevent a repeat of the same mistake later

on

FRACAS underscores the need to document the

guidelines relating to the definition, implementation, and

customization of FRACAS as a major element to achieve the

success of the program reliability. FRACAS basing on the

fact that the initial cause of the failure is identified and

corrective measures are implemented, the sooner the

manufacturer and users aware of the advantage against a

reduction in the occurrence of the failure factory or field. The

output of the information obtained from the FRACAS,

namely identify and verify the explanations of the correct and

accurate so that corrective actions can be taken appropriately

to prevent failure occurred again.

FRACAS Failure Process Analysis

Analysis of the failure is a condition in the roots of the

problem identification stage. Each failure must be verified

until the found factors cause the occurrence of failure [15]. In

the process of data collection, a lot of problems occur is

unknown due to the insufficiency of information available.

There are three main causes of the loss of important data, i.e.:

Inspection and testing that began before the existence of

the procedure of reporting failures.

Reporting Form that is difficult to use

Patroller/inspector who fill out the form of the failure is

not yet fully familiar with the goals and purpose of

making the form

In the reporting form of charging failure, the inspector or

the operator normally be first in identifying problems,

therefore, they should get the training well in advance in

order to capture all the information needed in reporting the

incident [15].

The analysis process consists of:

detailed Inspection reports from the field

Collecting historical data from the database pertaining to

or have the same failure



I J E N S

Determine the parties responsible for the action of the

root problem analysis

Develop corrective actions put together a broken item

for analysis of the root of the problem report analysis

Problem analysis report (PAR) and if necessary report

the disposition of materials/material disposition report

(MDR).

The Process Analysis of the Root Problem

The process analysis of the root problem is one of the

important process in determining the success of the

deployment FRACAS, this is due to any corrective action

taken be correct if the process of problem identification and

analysis of failure are also appropriate. Searches the root of

this issue aim to uncover the underlying reason or cause of

error corrective action taken so that it can fix the failures that

existed and to prevent the recurrence of the failure for a

repeat in the future. The effectiveness of the FRACAS was

limited to the accuracy of the data entered at the time of the

initial report. At least the reporting failure to contain

information that is most basic

Who is find the failure damaged

What (and what specific indications of failure)

Failures occur when the failure happening

How the condition can happen

FRACAS Framework

FRACAS is used by many functional disciplines including

reliability, design, testing, factories, quality control, and

maintenance. In order to overcome the barriers between

organizations, established a methodology in developing the

FRACAS. The reason why the FRACAS has the process in

the form of close loop i.e. so that engineers can monitor and

analyse your products/services on an ongoing basis in

improving the reliability of components or machines. A

circle formed provides programs to increase reliability

through repeated reporting process and the planned corrective

actions. With FRACAS provides information about system

failure, how and why failure can occur, and how to prevent

the fiasco happen again in the future. Documentation of

quality in determining the effectiveness of FRACAS in

generating an acceptable solution [12]; [2].

Source: Lee, Chan, & Jang, 2010

Fig. 1. Close Looped Failure Reporting, Analysis and Corrective Action

System

Close Looped Failure Reporting, Analysis and Corrective

Action System

There are two phases in the FRACAS made it a business

process [12]:

1. Stages of Discovery (Discovery Phase) at this stage, the

completeness of the business processes through the

implementation of the goals are obtained from the

investigation manual job, interview, and an analysis of the

existing systems. This stage of the process aimed at Figure 2

and the results of the discovery phase can be seen in table 2.

*Source: (Lee Chan & Jang, 2010)

Fig. 2. Tasha Penman (Discovery Phase)



I J E N S

TABLE II FRACAS DEFINITION PROCESS

Step Ownership Information

1 Observing the

failure of an item or product

User Observation data item

Time/location/environment

2 Documenting the

failure symptoms

and relevant information

Testing

Division Failure description of the

root problem

3 Verify failure Testing

Division Checklist

4 Isolate the item

with the lowest level of suspect

Testing

Division Failure mode

5 Repeated testing after the

replacement of

suspect items

Testing Division

Test Reports

6 Verify the failure of

isolated items

Testing

Division Description of the

verification reports

improvements 7 Failure analysis Reliability

Division Methods Of Analysis

Report

8 Looking for similar

failure history

Reliability

Division Search results and

Database

9 Make an analysis of

the root of the

problem

Reliability

Division Failure mechanism of

identification of the

root of the problem

10 Determine corrective action

based on

the results of the analysis

FRB Analysis results

11 Incorporates

corrective actions

for items

FRB Specifications action

12 Test the

operational performance,

verify corrective

actions new has no side effects

FRB Performance reports

13 Verify the effectiveness of the

actions proposed

FRB Effectiveness results

14 Incorporates

corrective

measures for

products

FRB Specifications action

Source: Lee, Chan, & Jang, 2010

2. Stage design (design phase) the design phase refers to the

phase of business process modelling standardized. Typically,

the computerized format so it can be easily accessed in IT

systems

FRACAS Failure Review Board (FRB)

FRB is a group consisting of representatives of the

Contracting Organization in accordance with the level of

responsibility and authority to ensure that the cause of the

failure is identified and corrective actions applied [13]. FRB

failure trend review, facilitates and manages the failure

analysis, and participate in developing and implementing

corrective action. Personnel designated as FRB must be

identified on the procedures and scope of authority including

the FRACAS. In General, the following is a representative

organisation for FRB [15].

Reliability

Field service

Statistic Method

System Engineering

Design Engineering

Quality Assurance

Manufacturing

Marketing

Test

FRB should preferably be headed by reliability manager.

One of the main functions of reliability manager is to set up

an effective FRACAS. Reliability manager should create

procedures, facilitate periodic review, and coached members

of the FRB. Other responsibilities are:

Assign any action by ownership problems

(who/what/when)

Allocate the problem to the appropriate functional

Department for corrective action

Analysis of behavior trends and inform management

about the type and frequency of failure

Failure mode and Track inquiries

Published periodic reports on the performance of the

product (MTBF, MTTR, productivity analysis) and an

improved area

Ensure problem resolution

Process to continuously review the FRB and make

adjustments against specific applications

In operating the FRB, it takes two support people, i.e. the

reliability coordinator and database support person. A

reliability coordinator can get goods failed to analyse the

roots of the problem, ensuring the incident report submitted to

the FRB contains enough information, maintaining

relationships with internal and external parties in the

Organization to ensure the clarity of the reports, and track as

well as facilitate the RCA for implementation of corrective

action. A database support is responsible for providing

periodic reports and to manage the database (importing.

Exporting data), backing up files, archiving old records. This

ensures the data available from RCA and corrective actions

are stored in the database.

FRB should make regular meetings to make the reported

problems. The frequency of meetings depends on the number

of problems or the volume of reports per day. The problem –

the main issue should be used to set priorities and allocate

resources. Priority assignment problem using Pareto analysis

retrieved from the database.

Task



I J E N S

Business Process Maintenance Corrective FRACAS

FRACAS is the tools used to identify and correct deficiencies

in a system or component, with FRACAS is believed to

process evaluation of downtime can run effectively and

prevent the failure being repeated again. The purpose of the

FRACAS as the provision of Engineering data that can be

used for corrective activity so that the data will be retrieved

historical reliability (Mean Time between Failure, Mean Time

to recover, availability, etc.), the development of something

that was still lacking and the provision of data for statistical

analysis. Basically, the use of the FRACAS has two main

perspectives, reliability-related information and operational

tasks. The information in the form of field data, report failure,

product specifications or part, and a profile that is associated

with the Engineer. Handling failure basically starting from the

data collection process is a failure; it is intended to failure

quickly handled.

One method that can be applied in dealing with the

downtime at Company PT X i.e. deployment FRACAS.

Deployment further FRACAS in the industry followed with

(1) the level of reliability and its attributes (in due dates,

ownership, and responsibility) that should be clearly clarified

and have been standardized; (2) the handling of Functionality

must be supported with the automation of tasks and

controlling processes. Corrective maintenance business

process description with FRACAS serves to provide an

explanation about the working of the system in terms of the

implementation of maintenance equipment factory in dealing

with the downtime that occurs. This procedure applies not

only at the Department of Mechanical environment PT X

only, but also include other stakeholders i.e. supplier, QA,

Dept. of production and management.

Source: Vila court & Govil.1993-1994. Failure Reporting, Analysis, and

Corrective Action System, SEMATECH Inc.

Fig. 3. FRACAS Process

IV. ANALYSIS AND RESULTS

Analysis of Downtime with Deployment FRACAS PT X

Any failures that occur during the inspection and testing

process reported in accordance with the applicable procedures

including in terms of gathering information and data recap

and time recorded. The data includes a reports must be

verified and then collect in the form of a simple (easy to use

form). In accordance with the structure of the organization

that is run at PT X has a Department of Mechanical

Maintenance as a special Department to perform maintenance

on the machine – a machine that exists. The magnitude of the

downtime that occurs in the Area of 561, resulting in reduced

productivity in producing cement Milling System in PT X.

failure happened caused by the subsystem of Milling System

is experiencing a reduction in reliability.

Milling System (MECAREA II) on PT X is the central area

of the production process are performed, so the parties often

seek to add to the design development on these areas to create

better production processes. Execution of development in this

area began in 2006; with the construction of the first phase is

done starting from the construction of the area of the Packer

which serves as packaging area, then to increase competitive

advantage in domestic cement industry development coupled

with the Milling area System as areas of grinding the material

up to now. Milling System consists of 5 subsystems which

were influential in the process of making cement. In Figure 4

shows the subsystems of the Milling System in cement

grinding process performed in PT X.

*Source: Company Data in 2012

Fig. 4. Milling System PT X (MECAREA II)

5 Subsystem in Milling System include:

1. Machine of Cement Mill

2. Bucket Elevator

3. Separator

4. Bag Filter

5. Air Slide

Downtime that occurred at PT X for example on the type

of failure that occurs in the Area of 561 i.e. use of Milling

System is not optimal, resulting in engine Cement Mill often



I J E N S

experience trip, besides grinding fresh material to overload

and resulting output does not match the standard. If the failure

is left continually impacted the reliability of machines

declined, which resulted in the appearance of defects that can

be detrimental to a company party. Therefore, in handling this

downtime required evaluation a thorough evaluation of each

stakeholder so that downtime with the same case doesn't

happen again and reliability as well as the resulting output

quality in compliance with the standard.

Corrective maintenance of the appropriate document Format

FRACAS

According to the vision to become a major player in national

economy, supported by an excellent workforce, quality

products, best service and integrated systems, required

evaluation of downtime are increasing from year to year. The

document reporting the failure (Failure Reporting Document)

that strongly supports the complete company party to achieve

the desired vision.

Collection and sharing of data through a report of the

incident became important in the deployment FRACAS,

either between the supplier and the company. There are main

elements in the reporting failures (when failure occurs, what

items are experiencing failure, etc.) that can be analysed the

failures experienced by the company and the supplier. The

other main information includes the duration of the failure,

the time used for repair and type matrixes used (time).

Each data sheet was very helpful. On the use of the

FRACAS, the supplier is requested to get detail information

from reports the failure on the part of the equipment. This can

help to determine the shape of the operation before and after

failure and also to determine the root of the failure of the

equipment effectively and efficiently. The table shows the

type of proposal form proposal form of failure that can be used

by the Inspector and Draft man in Milling System failures

reported to the Supplier. With the form, the company may use

the data to evaluate management tools and resources that are

required to determine the value of their effectiveness in the

deliberations of the evaluation at the time of the meeting.

TABLE III PROPOSED SYSTEM FAILURE DATA FORM AS AN EVALUATION

RESOURCESCAS DEFINITION PROCESS

Event Report Fields E

x

a

m

p

l

e

Description

Serial number

561 - BM

Identification location

system failure

Date and Ti me of Event 07.12.15 Info of event

Duration of Event

(downtime)

3.25h Duration of failure

Failed Item Description inlet head mil

couldn't fill all material

grid nidi ng process s

Description of failure

Reliability/Fault Code of

known Problems

BM - Inlet - 01 Failure code

Downtime Category

(Maintenance a cti on)

Unscheduled Failure category

Opera tor's name Mr. Ha mi d Those who reported

Event

(Problem Description)

Cement mill has

been

blocking a t inlet

mill and tri p

because of mi l overhead t

Description of failure

Document corrective action

PT X has document corrective action in the form of a

notification and Finding a List then processed into document

MUWOS/MUWOL. Figure 4.9 shows a sample Notification

creation and Finding Lists that have been applied in PT X. in

reporting the failure as in the picture above, the findings

obtained does not contain elements of the analysis, as the

analysis process is not well documented such as the rule-

making process of the FRACAS.

Component on Finding List obtained in the form of:

A description of the failed items that must be improved,

Improvement, priority Number Estimation of material

used,

The number of the item to be replaced,

Man power in charge of fixing, and the types of damage

are written in the column remarks.

While in the notification form, existing components, namely:

Title notification date and time the notification priority

Types

Repair (urgent/preventive/long shutdown)

Repair location/Area name request work

name work received responsible Department

In making the documentation for corrective actions starting

from the Notification List/Finding finally processed into work

orders. In making a work order will be published

MUWOS/MUWOL to run the maintenance process. The thing

that differentiates with FRACAS is making process after he

made work orders created documentation failure report

includes documentation of root cause analysis and storage of



I J E N S

photographic file as evidence of failure that occurs. With the

use of a FRACAS in identifying the cause of the failure,

causing the need for adjustments to the standard Procedure

between PT X with FRACAS. Evaluation process downtime

done PT X using FRACAS (Failure Reporting, Analysis and

Corrective Action System) has the stages that in accordance

with a procedure to be executed.

Evaluation of failure on downtime by using a method

proposed by FRACAS form Problem Analysis Report (PAR),

in the form of this action will be carried out of the

investigation regarding the problems occurred.

1. Error code is filled in accordance with the number of

errors occurred, if an error has been occurred previously,

the inspector who filled it can write in accordance with

the previous code, but if not, the inspector can write new

code for the type of failure. Writing error code is useful

for measuring the effectiveness of corrective measures

after implementation.

2. Problem title is filled with the type of failure that occurs.

3. FRB member, filled with the party which found the

failure and will analyse the failure

4. Assignee, filled with parties that find and analyse the

failures occur.

5. Type of Problem, this column is divided between two

options, namely the common and unique. The company

can provide party checklist if the problems occurred are

common in the common column, and can affix checklist

in column unique if the problems occurred are new.

6. Category, in this column also gives the option. If the

type of error that occurred interferes with the working of

the machine at the time of operation, the company can

provide a checklist on this column, if the type of error

that occurred related to conditions in the warehouse, the

company can provide a checklist in the proc, and if an

error occurs is the category of the design of the

machines, the company can provide a checklist on the

category design times.

7. Date info, shows the date found problems.

8. Definition of the problem, in this column describes the

main conditions relating to the problems occurred and

how inspector categorizes that problems occur on

objects that are found.

9. Chronology, explained the chronology of failure that

occurs. Failure events are explained in clear and

coherently in order for failure can be identified by

either.

10. Root cause analysis, explaining the roots of the

problems occurred.

11. Action suggestion for no repetition, those suggestion

actions taken is determined from the results of the

analysis of the root of the problem. The overall cause of

the failure is discussed to determine long-term solutions

that might be applied so that the problem doesn't happen

again.

12. Constraints, obstacles that are obtained when need to do

repairs.

13. Action done & action plan including PIC, an action that

has been made in addressing the problem and planning

further action 2.

14. Approved by, is the column an endorsement signed by

Mechanical Dept. Head as party boss who agree about

problems that occur and agree to do corrective action as

well as the signature of planner as the parties agree to

promptly scheduled corrective actions in handling the

issue.

15. Prepared by, filled by parties that finds and analyse

problems

. Data Processing Time After Malfunction in a subsystem can

affect the reliability of the testing distribution is done then

every subsystem. The reason that he did the testing distribution

due to data that is used there is a variable time to change

continuously (continuous). So the prediction engine

maintenance can actually condition approaching then

performed testing the distribution of data – data damage. There

are two phases in determining the distribution of failure,

namely:

a. The identification of the/index distribution of candidates

fit distribution (exponential test, Weibull, lognormal and

normal).

b. Hypothesis Test (Goodness of fit test)

Cement Mill Machine subsystem

Cement Mill in Figure 4 is a machine used to grind materials

to reduce the size of sub-materials is output that corresponds

to the desired standard. Specification of Cement Mill PT X:

Function: Grind material additive with clinker and gypsum

Capacity: 150 tons/hour

Mill Drive: GMD AB Drive: 3 Phase

Motor Ring Synchrone: 5.2 MWatt

Diameter length: 4.8 m x 16 m speed: 9.0 RPMs

Fig. 5. Cement Mill

The captions figure:

1. Feed Chute

2. Feed Cone Mill Shell(Liner)

3. Insulation The Diaphragm

4. Ball mill

5. Discharge cone



I J E N S

This machine is used to perform the mixing process of

grinding clinker and gypsum additive material with others.

This grinding process is generated by products in the form of

cement with the desired fineness. Cement mill made of steel

with a horizontal shape consisting of 2 chambers. On the

inside of the inlet, there is a mill called the shell with a liner

that has a composition made of steel cast mounted the wall

attached to the cement mill. Its function is to keep the

collision of ball mill with shell mill, resulting in usage of

cement mill into a more durable and not quickly broken when

grinding process is done. In addition the function of the liner

also helps in the process of grinding. With its wide array of

ball mill can be helpful in destroying the existing material.

On cement mill there are 2 different compartments, with

this type of liner and size of ball mill. Between the two was

divided into 2 compartment bulkhead with an open diaphragm.

After the material was destroyed in the first disc compartment

will enter a compartment both through the diaphragm to the

boundary of mashed again. After smoothing is done, the fan

and the Damper serves to attract material that has a subtle

heading separator, while the coarse material was taken using

bucket elevators to do the separation heading separator, after

the separation of the material has done fine will be taken to a

temporary shelter as a silo prior to packaging, while still rough

going at the recycle return to cement mill for grinding back in

accordance with the desired specifications.

TABLE IV

THE DISTRIBUTION OF CEMENT MILL MACHINE

Exponential Weibull Normal Lognormal

0.848652245 0.8313009 0.979638695 0.740026929

Recap of Least Square

Based on the calculation of index of fit has done then retrieved

the value of r is the largest in a Normal distribution. Because

the value of r is the correlation values shows a trend of data following the distribution of damage, one that needs to be

done for testing goodness of fit test using Minitab to see its

discrepancies with calculation using software.

Goodness of Fit Test

The steps do testing on Minitab 16 is on the menu Stat >

Reliability/Survival > Distribution Anaysis (Right Censoring)

> ID Distribution Plot. Subsystem failure data of Cement Mill

obtained results in Figure 6. The suitability of the distribution

can be seen from how data fit with straight lines on each

distribution. The closer the distance data with lines even ter-

plot line, the more suitable the distribution data. Software

minitab also provides other parameters for goodness-of-fit

like the value of Anderson's Darling and Corelation.

Corelation's shows the relationships between the data. The

higher the value is then deemed to be the better the

relationships between the data so that the values in the

distribution of the more appropriate. The test results of

Goodness-of-fit it using Minitab can be seen in the value of

the AD (Anderson Darling) is the smallest.

Fig. 6. Goodness of Fit Subsystem Cement Mill with Correlative's

Fig. 7. Goodness of Fit

On the probability plot and image value Anderson Darling

shows most data in accordance with the Normal distribution.

Reliability calculation of engine

Reliability is affected on the reliability components that work

in it. The engine in the industry is very important in

supporting the passage of the production process so that the

establishment must be kept. The value of the reliability of the

machine can give you an idea of how reliable the machine

working so can be determined actions to maintain or increase

reliability. In calculating the reliability using data damage any

component of the machine and examined its use in

determining the parameters of the MTTF and reliability.

In carrying distribution test, it has been gained the proper

distribution to Cement Mill subsystem which is a normal

distribution. Therefore, the calculation of its parameters is

done with normal distribution. Here the steps for calculating it

by using Minitab 16 software:

Stat > Reliability/ Survival > Distribution Analysis (Right

Censoring) > Parametric Distribution Analysis.

Subsystem failure data of Cement Mill obtained results as

Figure 6.

Parameters σ = 1130.65

Parameters μ = 3004.02

MTTF = 3004.02



I J E N S

To calculate a reliability subsystem Cement Mill,

using the parameters – parameters has been obtained, by

using t = 2995.09, so obtained:

R (t) = 1- ɸ

((t-μ)/σ………………………………….. (8)

= 50 %

Maintenance Interval determination

Based on the reliability of the subsystem Cement Mill can be

calculated interval the subsystem should undergo treatment.

To achieve reliability average with a target of 80% then it can

be made with maintenance interval simulation 6264. The

desired reliability is of 80%, whereas before implementing

Preventive Maintenance, reliability that can be reached is 50%

at the moment to achieve 3004.02 hours (MTTF).

Fig. 8. Parametric Subsystem Cement Mill

Therefore, the need for action to improve the situation.

Based on the simulation contained an attachment retrieved

intervals of treatments done is every 2016 hours once (2.8

months). By doing preventive maintenance with an interval of

2016 hours on 3004.02 hour Cement mill has opportunities for

time t reliability – not of actions of preventive maintenance,

R (t-nT) or (t- n T) = 1 - ɸ ((t – n T)-μ)/σ

………………………… (9)

R(988) = 0.9625

So the chances of the reliability of the system conducted

preventive maintenance Rm(t) by

Rm (3004) = R(2016)1

x R (988) = (0.5) x

(0.9625) = 0.7775

Increased reliability = 77.75%-50% = 29

Figure 7 shows comparison chart of reliability before and after

the proposed preventive maintenance:

Fig. 9. Graphics Subsystem Reliability Improvement of Cement Mill

V. Conclusion

1. Note that the Milling System Area is often repeated

failure, so proper identification failure to correct any

failure that occurs and preventive action so that the

machine can reliable. Based on Pareto analysis obtained

level of downtime that occurs in the area of 561 Milling

System i.e. 37.5% of downtime is due to damage of

cement mill with the kind of general problems often

experienced that is spilling material on inlet process prior

to grinding mill.

2. Failure on the machine with the use of the FRACAS

(Failure Reporting, Analysis and Corrective Action

System) involves a process that includes observations of

failures that occur, and then documented the symptoms of

failure that occurs. After verifying that the failure of the

items fail performs failure analysis using the form

FRACAS, looking at the history of similar failure then

determining corrective action based on the results of the

analysis.

3. At the end of the use of the FRACAS, to reduce the risk of

failure to return at a later date, risk mitigation done by

calculating the right maintenance interval design for

Milling System are: Decreasing the risk of failure of the

Cement Mill with increased reliability of 29%, preferably

carried out preventive maintenance intervals with interval

of 2016 hours

Advice

1. Expected with the use of the FRACAS, the company may

record the kind of damage that occurs more detail so that it

can facilitate The Mechanical in doing treatments

specifically for the creation of proper maintenance

schedule.

2. Expected to be part of the inspector who identified

problems are often given training about data, in order to

better understand the intent and purpose of the making of

the FRACAS form.

REFERENCES

[1] A. E. Rahma, "Perancangan Sistem Pemeliharaan Korektif dengan



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Menggunakan Failure Reporting, Analysis and Corrective Action System (FRACAS)," Jurnal Ilmiah Universitas Bakrie, vol. 3, no. 03,

Agustus 2015.

[2] M. Banghart and D. Nicholls, "An Improved FRACAS/DCACAS Implementation Model.," The Journal of Reliability, Maintainability, &

Supportability in Systems Engineering, vol. Summer 2012, pp. 10-15,

2012.

[3] C. M. Gustafsson and J. Ullberg, "Failure handling in product

development- A study within Volvo GTT Powertrain Engineering

(Master’s Thesis)," Department of Technology Management and Economics, Göteborg, Sweden:, 2012.

[4] L. R. Higgins, R. K. Mobley and D. W. , Maintenance Engineering Handbook, 7th Edition,, McGraw Hill Professional , 2008.

[5] Sisjono and I. Koswara, Pemeliharaan dan Perbaikan Komponen-

komponen Alat . Edisi Revisi, Jakarta: Erlangga, 2004.

[6] A. Telang, "Preventive maintenance," in Proceedings of the National

Conference on Maintenance and Condition Monitoring, Hissur, India,,

14 February 1998.

[7] F. Herbaty, Handbook of maintenance management: Cost-effective

practices., Park Ridge, N.J., U.S.A: Noyes Publications. , 1990).

[8] I. Ahuja and J. Khamba, "Total productive maintenance: literature review and directions," International Journal of Quality & Reliability

Management, vol. 25 , no. 7, pp. 709 - 756, 2008.

[9] E. T. Higgins, "Knowledge activation: Accessibility, applicability, and salience.," in Social psychology: Handbook of basic principles, E. T.

Higgins & A. W. Kruglanski (Eds.), Ed., New York: Guilford Press.,

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[10] C. E. Ebeling, An Introduction to Reliability and Maintainability

Engineering,, Singapore: McGraw Hill Book Co, 1997.

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[12] J. H. Lee, S. Chan and J. S. Jang, "Process-Oriented Development of

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Sematech, 1993.

Tri Susanto received his master degree in industrial engineering from

Bandung Institute of Technology (ITB). Currently, he is a lecturer in

Industrial Engineering of Universities Bakrie, Indonesia. He taught several

courses such as Theory of Probablity, Industrial Statistics, Operation

Research, Project Management. Aurino RA Djamaris is a lecturer of Management Department of

Universities Bakrie, Indonesia. He taught several courses such as applied

business computation, Maths and Statistics, Decision Modelling, Logistics &

Supply Chain, Production and Operation Management.

Mirsa D. Novianti received her undergraduate and master degree in Industrial

Engineering from University of Indonesia. Currently, she is a lecturer in

Industrial Engineering of Universities Bakrie, Indonesia. A number of courses

that she taught are Layout, and Quality Control.

Fidya Ayu Saomi is a student of Industrial Engineering at Universities

Bakrie, Indonesia.

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