About this previous year paper
SECTION A
(2 × 10 = 20 marks | Short Answers)
a) Maintenance planning
Maintenance planning is the systematic scheduling and organization of maintenance activities to ensure equipment reliability with minimum downtime and cost.
b) Objectives of maintenance
Maximize equipment availability Reduce breakdowns
Ensure safety Minimize maintenance cost
Improve equipment life
c) MTBF (Mean Time Between Failures)
MTBF is the average operating time between two consecutive failures of a repairable system.
MTBF=Total operating timeNumber of failuresMTBF = \frac{\text{Total operating time}}{\text{Number of failures}}MTBF=Number of failuresTotal operating time
d) Role of maintenance economics
Maintenance economics helps in optimizing maintenance cost by balancing preventive maintenance, breakdown cost, spare parts, and downtime losses.
e) Routine maintenance
Routine maintenance includes regular inspection, cleaning, lubrication, and minor adjustments carried out daily or weekly to prevent failures.
f) Eight pillars of TPM
Autonomous maintenance Planned maintenance
Quality maintenance Focused improvement
Early equipment management Training and education
Safety, health & environment TPM in administration
g) Condition monitoring
Condition monitoring is the continuous or periodic measurement of equipment parameters to detect early signs of failure.
h) Use of correction monitoring
Correction monitoring helps in detecting deviations from normal operating conditions so corrective actions can be taken before breakdown occurs.
i) Age-dependent failures
Failures whose probability increases with time or usage due to wear, fatigue, or corrosion are called age-dependent failures.
j) Unpredictable failures
Failures that occur randomly without prior warning, often due to sudden overload or manufacturing defects.
SECTION B
(Attempt any 3 | 10 marks each)
a) Maintenance organization structures
Centralized: All maintenance handled by one department
Decentralized: Maintenance at departmental level
Combined: Mix of both
These structures ensure better control, faster response, and cost efficiency.
b) Maintenance categories Breakdown maintenance
Preventive maintenance Predictive maintenance
Corrective maintenance
Selection depends on equipment criticality, cost, downtime impact, and safety.
c) Instruments used in Condition Monitoring
Vibration analyzer: Detects imbalance, misalignment Thermal camera: Identifies overheating
Oil analysis: Detects wear particles Ultrasonic detector: Finds leaks and bearing faults
d) Repair methods for machine beds
Scraping Grinding
Metal stitching Epoxy resin filling
These restore alignment, rigidity, and precision.
e) Hydraulic and pneumatic equipment in material handling
Hydraulic lifts Pneumatic conveyors
Actuators and valves
Maintenance includes leak inspection, lubrication, pressure checks, and filter cleaning.
SECTION C
Q3 (Attempt any one)
a) Economic efficiency through maintenance planning
Proper planning reduces unexpected breakdowns, downtime losses, spare inventory cost, and improves machine utilization and productivity.
b) Corrective vs Preventive vs Predictive maintenance
| Type | Nature | Cost |
|---|---|---|
| Corrective | After failure | High |
| Preventive | Time-based | Medium |
| Predictive | Condition-based | Lowest (long run) |
Predictive maintenance is most cost-effective in the long run.
Q4 (Attempt any one)
a) Fixed time vs Condition-based maintenance
| Aspect | Fixed Time | Condition-based |
|---|---|---|
| Schedule | Time-based | Data-based |
| Cost | Higher | Lower |
| Efficiency | Moderate | High |
b) Role of FMEA
FMEA identifies potential failure modes, their causes, and effects, helping prioritize preventive actions and improve reliability.
Q5 (Attempt any one)
a) Cost factors in Condition Monitoring
Equipment cost Training cost Data analysis cost
CM reduces breakdown losses and downtime, making it cost-effective compared to reactive
maintenance.
b) Temperature-sensitive tapes
These tapes change color at specific temperatures, helping detect overheating in bearings, motors, and electrical panels.
Q6 (Attempt any one)
a) Importance of failure analysis
Failure analysis identifies root causes, prevents recurrence, and improves machine life.
Steps: Data collection
Inspection Cause analysis
Corrective action
b) Logical fault location
It uses systematic elimination techniques to trace faults step-by-step, reducing repair time and guesswork.
Q7 (Attempt any one)
a) Repair methods for material handling equipment
Welding Replacement of worn parts
Lubrication Alignment correction
These ensure smooth operation and longer service life.
b) Downtime minimization
Using job order systems, preventive schedules, trained manpower, and quick-response repairs reduces equipment downtime.