Time Based Maintenance & Condition Based Maintenance

TBM ( TIME BASED MAINTENANCE) -

• It is also called a Periodic Maintenance coming under the Preventive Maintenance.
• The period of repair is chosen based on the parameter
• Production volume, pieces, or number of operating days.

Advantages :
It does not take manpower or time for inspection.

Disadvantages :
Repair cost are high because of over- maintenance.

Time Based Maintenance activities are selected on the basis of Equipment Supplier’s recommendation and past performance of the Equipment.
Periodic Inspection, cleaning, servicing, part replacement, lubrication and oil replacement activities are carried out at predetermined intervals to restore the Equipment deterioration.


CBM ( CONDITION BASED MAINTENANCE)

• Monitor and analyze the deterioration data regularly and constantly.
• Repair if the deterioration parameter reaches a predetermined critical value.

Advantages :
CMB can prevent over – maintenance, which is a problem with TBM.

Disadvantages :
Equipment diagnosis and monitoring system can be costly.

If Diagnosis is reliable, standard value can be set near the limit line.
This is the most economical method.
Predictive Maintenance highly depends on level of diagnostic techniques.
Wrong diagnosis is dangerous.

PLANNED MAINTENANCE - PHASE 4

PREDICTIVE MAINTENANCE

- Estimation of failure means by equipment diagnosis
§ Leakage, cracks, corrosion, irregular sound, irregular temperature, irregular vibration, oil deterioration, electrical
- Estimation of service life and its extension by technical analysis of catastrophic failure
§ Analysis of cross section of failure
§ Analysis of gear material fatigue
§ Analysis of gear tooth surface

PLANNED MAINTENANCE - PHASE 3

TIME BASED MANAGEMENT

- Estimation of service life and time based restoration or replacement - Reduce MTTR
§ KAIZEN of maintainability
- Understanding the irregularity for internal deterioration by using five senses
§ Distinction between those which show signs and those which do not
§ What sign would be considered as leading to failure
§ Why it was not detected in advance?

PLANNED MAINTENANCE - PHASE 2

EXTEND LIFE SPAN

- Extend inherent equipment life
§ KAIZEN of weakness in design
§ KAIZEN in weakness for overloading
- Elimination of accidental failure
§ Improper operation : Fool proofing, training
§ Improper repair : skill identification, gap analysis, training
- Restoration of exterior deteriorationDust ,Corrosion, vibration

PLANNED MAINTENANCE - PHASE 1

INCREASE MTBF

- Restoration of unattended deterioration
(Rectification of revealed defects)
- Elimination of forced defects
> Establish original equipment or basic conditions
> Maintain the right operating condition

PLANNED MAINTENANCE ACTIVITIES

FOUR PHASES

- Phase 1 : Increase MTBF
- Phase 2 : Extend the life span
- Phase 3 : Time based Maintenance
- Phase 4 : Predict failures

TYPES OF MAINTENANCE

· Maintenance activities to prevent / fix failures
o Preventive Maintenance
§ Time based maintenance
– Daily checks, Periodic checks, Periodic servicing
§ Condition based maintenance
– Rotating equipment diagnostic
– Static equipment diagnostic
o Breakdown Maintenance
· Improvement activities to expand life span / to shorten maintenance time / to avoid maintenance
o Corrective maintenance
o Maintenance prevention