maintenance modules
DESCRIPTION
Maintenance Modules. GROUP MEMBERS AMARASENA R.G.C. : 061004D DAYANI . J : 061011V NUWAN .U.P.A : 061040H PAHATHKUMBURE. K.M.D.K.B : 061042P THAASAN S. : 061053B WICKRAMARATHNE T. I. :061060T. - PowerPoint PPT PresentationTRANSCRIPT
Maintenance Modules
GROUP MEMBERS
AMARASENA R.G.C. : 061004D
DAYANI . J : 061011V
NUWAN .U.P.A : 061040H
PAHATHKUMBURE. K.M.D.K.B : 061042P
THAASAN S. : 061053B
WICKRAMARATHNE T. I. :061060T
What is Maintenance?
The maintenance department is one of the greatest levers of profitability that any capital intensive organization has.
An average of 40 – 50% of a capital intensive industries operating budget is consumed by maintenance expenditure.
With the advances today in technology affecting maintenance this figure can be greatly reduced. As such maintenance is often an organizations largest single controllable expense.
Maintenance
Maintenance Types
Planned Unplanned
Unplanned maintenance
• Reparation will be conducted after the equipment fails
• Used when the equipment failure does not considerably affect the operations or generate any notable loss other than the repair cost
Unplanned Maintenance cont…
Advantages• Low maintenance cost• Low maintenance staffDisadvantages• High down time• Lower operational efficiency• Low quality outputs• Impaired health & safety
conditions
Planned Maintenance
Planned maintenance is organized and executed with planning and control by utilizing the application of recorded data.
It encompasses condition based maintenance, which is planned and progressed information received about a system or company structure's condition.
This information is gleaned from routine or continuous monitoring processes and preventative maintenance.
Advantages of planned maintenance
Releases front-line foremen from major planning duties and allows them more
time to supervise their crews. Provides procedures to plan, execute,
monitor and control maintenance resources.
Reduces delays in waiting for men, material, tools after a job is in progress.
Provides for systematic collection of materials prior to planned jobs.
Provides procedures to implement and continue a PM program
Planned Maintenance types
• Preventive Maintenance• Corrective Maintenance
Preventive Maintenance
Preventative maintenance is carried out at predetermined intervals or according to prescribed criteria, with the intention of reducing the probability of failure or the performance degradation of a system.
PM includes painting, lubrication, cleaning, adjusting, and minor component replacement to extend the life of equipment and facilities.
Purpose is to minimize breakdowns and excessive depreciation. Neither equipment nor facilities should be allowed to go to the breaking point.
To minimize the risk, has to be carefully planned and carried out by well-trained and motivated workers.
Advantages of preventive maintenance
Improved system reliability.Decreased cost of replacement.Decreased system downtime.Better spares inventory
management.
Corrective maintenance Maintenance actions
carried out to restore a item that can be failed in to a specified condition
Improve equipments enabling the preventive maintenance to be carried out easily
Equipment with design weakness will be redesigned
Advantages of Corrective Maintenance
Enhanced component life time Enable prior corrective actions Lower equipment downtime Quality improvement of the
products Enhanced the safety Strengthened worker moral Save energy
Disadvantages of Corrective Maintenance
Higher investment in diagnostic equipment
Higher investment for training
Corrective Maintenance Types
• Maintenance actions based on actual conditions
• Reparation of a machine which gives an unusual sound can be identified as an example
• Can identify and rectify problems at an early stage and can improve machinery reliability
Condition Based Maintenance(Predictive Maintenance)
Opportunistic Maintenance
Reparation of the components which are found to be defective or needs replacement in the immediate future
The components will be identified during the maintenance of a sub-system or a module
Opportunistic Maintenance cont…
As an example, identifying and rectifying a defective feeder, during the maintenance actions carried out for a faulty stitch cam in a knitting machine
Routine Maintenance• Includes activities which
are perform in planned basis to maintain and protect the conditions of equipments /processes
• Most simplest type of planned maintenance
• Oiling knitting machines in can be identified as an example
Design Out Maintenance• Design modifications to stop
the failure from occurring • Usually conducted based on
the past experiences• As an example; a design
modifications conducted to a yarn feeding finger in a knitting machine to avoid having plating effect. The identification the fault and designing the finger will be conducted based on the past experience
Other Maintenance Types
Reactive Maintenance• No measures are taken to
maintain the equipment because the designer should ensure that the design will reach it’s life time
Reactive Maintenance cont…
Advantages• Lower cost• Less staffDisadvantages• Increased unplanned downtime cost• Repair / replacement of equipment cost• Other equipment or process damage
due to the equipment failure
Maintenance Prevention Indicates a design
of a new equipment Drawbacks of
existing machines are studied before designing the new equipment
Maintenance Prevention cont…
• Rieter, developed modern rotor machines with innovative bearing and lubrication techniques
• This reduce the maintenance requirements in the modern machines than in the conventional rotor machines
Maintenance Prevention cont…
Advantages• Lower maintenance cost• Lower machine downtimeDisadvantagesHigher investment for trainingHigher investment for equipments
and technology
Maintenance ModelsMaintenance Models
ReplacementReplacementWhy?Why?
Company
Employee
Target
AchievementEmployee
&Machines
Replacement
Employees Machines
Immediate replacement after failing With continuous failureWith expectation of failure
Age Replacement Model
Time
Age
of M
achi
ne
T TTT
For the equipments of which cost of repair is higher if it fails while operating Cost of maintenance involves
Down time loss Cost due to low efficiency Replacement cost Down time cost
Assumptions of the ModelAssumptions of the Model
Cost of maintaining the equipment increases as the
equipment ages
The equipment used is operating continuously or
intermittently
Down time for repair and maintenance is ignored
The planning horizon is infinite
Every new piece of equipment has identical characteristics
Calculating the ‘T’ value Calculating the ‘T’ value
Total cost = Replacement cost + Maintenance cost – salvage value
G(t) = K + C(t) – S(t)
Time
Cost
Breakdown Cost
Maintenance Cost
Total Cost
Salvage Value
T
Min
imum
tota
l co
st
Advantages and Disadvantages of Advantages and Disadvantages of the Age Replacement Modelthe Age Replacement Model
Advantages• Simple and basic calculation• Once calculation is done it can be used for long time until
the characteristics of the product is changed
Disadvantages• Not suitable for the products of which characteristics are
changed time to time• This model does not consider about the unplanned
breakdowns of machines
Applications of the model in Applications of the model in Textile and Clothing IndustryTextile and Clothing Industry
For the vehicles used in both industries
For the changing time of auto cutter unless knife
is broken
Replacement of sewing machines
Planned replacement on Planned replacement on uncertaintyuncertainty
Replacing before it fails
Is it worthwhile doing a Is it worthwhile doing a planned replacement?planned replacement?
How likely it will happen?
How do we quantify it?
Probability
Impact
Planned replacement without a review
Consequences might be not worthwhile
No advantage in avoiding the failure
Throw out unused life away
Get nothing
Planned replacement should reduce the chances of a failure
Replaced part or person should perform better than the previous or be more reliable
For this :
Reliability
Failure
Replaced item Old item
Planned replacementPlanned replacement
Individual replacement
Group replacement
QuestionsQuestions ??? ???
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