Maintenance Management: Breakdown, Preventive & Predictive Maintenance, TPM, Reliability and Maintenance Planning (Basics) Questions

Question 1

Define maintenance.

Accepted Answer

**Maintenance** is the set of activities carried out to keep equipment in, or restore it to, a condition in which it can perform its required function.

Question 2

What is breakdown (corrective) maintenance?

Accepted Answer

**Breakdown maintenance** is maintenance performed **after a failure** to restore the equipment to working condition.

Question 3

What is preventive maintenance?

Accepted Answer

**Preventive maintenance (PM)** is planned maintenance carried out at predetermined time intervals to reduce the probability of failure.

Question 4

What is predictive (condition-based) maintenance?

Accepted Answer

**Predictive/condition-based maintenance** is maintenance performed based on the actual condition of equipment measured using monitoring techniques (e.g., vibration/temperature/oil analysis).

Question 5

What is TPM?

Accepted Answer

**TPM (Total Productive Maintenance)** is a company-wide approach to maximize equipment effectiveness by involving everyone and aiming for **zero breakdowns, zero defects and zero accidents**.

Question 6

Expand MTBF.

Accepted Answer

**MTBF** = **Mean Time Between Failures**.

Question 7

Explain objectives of maintenance management (any four).

Accepted Answer

Objectives of maintenance management (any four):

- reduce **breakdowns** and unplanned downtime.
- increase equipment **availability** and productivity.
- ensure safety of workers and compliance with standards.
- maintain consistent product quality by keeping machines stable.
- extend equipment life and reduce replacement cost.
- minimize total cost (maintenance cost + downtime loss).

Thus, maintenance supports smooth production at optimum cost and high reliability.

Question 8

Differentiate breakdown, preventive and predictive maintenance (any three points) with a table.

Accepted Answer

### **Breakdown vs Preventive vs Predictive Maintenance**

- **Breakdown**: after failure; unplanned; higher disruption.
- **Preventive**: time-based planned actions to reduce failure probability.
- **Predictive**: condition-based; maintenance done when indicators show deterioration.

Table:

| Type | Trigger | Key feature | Typical use |
|---|---|---|---|
| **Breakdown** | failure | reactive repair | non-critical assets |
| **Preventive** | time/usage | scheduled checks & replacement | stable operations |
| **Predictive** | condition data | monitors health & predicts failure | critical rotating machines |

Hence, predictive avoids both extremes: run-to-failure and over-maintenance.

Question 9

Explain preventive maintenance procedure (steps) and any two advantages.

Accepted Answer

### **Preventive Maintenance (PM) Procedure**

Steps (brief):
- prepare PM schedule (daily/weekly/monthly) for each machine.
- perform routine **cleaning, lubrication and inspection**.
- replace worn parts before failure.
- maintain records/history and revise the PM plan.

Advantages (any two):
- reduces unplanned **breakdowns** and smoothens production.
- improves safety and quality; increases machine life.

Thus, PM is a planned approach to reduce failure probability and downtime losses.

Question 10

Explain predictive (condition-based) maintenance and mention any three techniques.

Accepted Answer

### **Predictive / Condition-Based Maintenance (CBM)**

Predictive maintenance uses **condition monitoring** data to decide when maintenance is required.

Key idea:
- measure condition indicators; if trend shows deterioration beyond a limit, plan maintenance before failure.

Techniques (any three):
- **vibration analysis**
- **thermography** (infrared)
- **oil analysis**
- ultrasonic testing

Hence, CBM reduces downtime and avoids unnecessary scheduled maintenance.

Question 11

Explain maintenance planning and scheduling (basics) with a simple flow.

Accepted Answer

### **Maintenance Planning and Scheduling**

- **Planning** answers **what and how**: job method, manpower, tools, spares, time estimate.
- **Scheduling** answers **when**: allocate the planned jobs to time periods considering production plan.

Simple flow:

```text
Identify job → Plan resources & method → Schedule time slot → Execute → Record feedback → Improve plan
```

Thus, good planning + scheduling reduces waiting time, improves coordination and minimizes downtime.

Question 12

Explain planned maintenance and unplanned maintenance (any three points) with a table.

Accepted Answer

### **Planned vs Unplanned Maintenance**

- **Planned maintenance** is scheduled (PM/CBM) and resources are prepared in advance.
- **Unplanned maintenance** is emergency work after a breakdown; it disrupts production.
- Planned maintenance generally results in **lower downtime** and better cost control.

Table:

| Basis | **Planned maintenance** | **Unplanned maintenance** |
|---|---|---|
| Timing | scheduled | sudden/emergency |
| Preparation | manpower/tools/spares arranged | rush arrangement |
| Impact | less disruption | high disruption |

Hence, moving from unplanned to planned maintenance improves reliability and production continuity.

Question 13

Explain TPM and its key pillars (exam-style) and show OEE components in a small table.

Accepted Answer

### **TPM (Total Productive Maintenance) — Exam-Style**

**Meaning:** **TPM** is a company-wide maintenance approach focused on maximizing equipment effectiveness by involving **operators, maintenance staff and management**.

#### **Goals of TPM**
- **zero breakdowns**
- **zero defects**
- **zero accidents**

#### **Key Pillars (overview)**
- **Autonomous maintenance**: operators perform basic care (cleaning, lubrication, tightening).
- **Planned maintenance**: scheduled and condition-based maintenance planning.
- **Focused improvement (Kaizen)**: continuous elimination of losses.
- **Quality maintenance**: prevent defects by controlling equipment conditions.
- **Training and education**: build skills for operators and maintenance.
- **Safety, health and environment**: safe workplace and zero accidents.

#### **OEE (Overall Equipment Effectiveness) — Components**

| Component | What it captures |
|---|---|
| **Availability** | downtime losses |
| **Performance** | speed losses |
| **Quality** | defect/rework losses |

**Conclusion:** TPM creates shared ownership of equipment, reduces losses and improves OEE through systematic maintenance and continuous improvement.

Question 14

Explain MTBF, MTTR and availability. Also show how to improve availability (exam-style with a small table/flow).

Accepted Answer

### **MTBF, MTTR and Availability — Exam-Style**

#### **Definitions**
- **MTBF (Mean Time Between Failures):** average operating time between failures.
- **MTTR (Mean Time To Repair):** average time taken to repair and restore equipment after failure.
- **Availability:** proportion of time the machine is available for production.

A commonly used relationship (conceptual):
- Availability ≈ **MTBF / (MTBF + MTTR)**

#### **How to improve availability**
- Increase **MTBF** by reducing failure frequency:
  - strong **preventive maintenance**, good lubrication, correct operating practices
  - condition monitoring to detect deterioration early
- Decrease **MTTR** by faster repair:
  - trained technicians, standard procedures
  - right tools and **critical spares** available
  - good troubleshooting and quick access to manuals

Mini table:

| Improve | What to do | Result |
|---|---|---|
| **Increase MTBF** | prevent/avoid failures | fewer breakdowns |
| **Decrease MTTR** | faster restoration | less downtime |

Flow:

```text
Higher MTBF + Lower MTTR → Higher Availability → Better delivery + lower downtime cost
```

**Conclusion:** Reliability metrics convert maintenance performance into measurable targets and guide improvement actions.

Question 15

Explain spare parts management in maintenance and why it is critical (exam-style with a table).

Accepted Answer

### **Spare Parts Management in Maintenance — Exam-Style**

Spare parts availability directly affects **repair time (MTTR)**. Even if technicians are ready, the machine cannot be restored without required spares.

#### **Why it is critical**
- prevents long downtime due to waiting for parts.
- improves equipment availability and delivery reliability.
- reduces emergency purchases and high procurement cost.
- supports planned maintenance and faster breakdown response.

#### **Key practices**
- classify spares by **criticality** (often VED) and value.
- set **reorder level** and safety stock for vital spares.
- standardize parts and maintain accurate stores records.
- track lead times and consumption history.

Table:

| Practice | Benefit |
|---|---|
| **Criticality classification** | focus on vital spares |
| **Reorder + safety stock** | avoid stock-out |
| **Standardization** | fewer varieties, lower cost |
| **Accurate records** | faster issue and replenishment |

**Conclusion:** Effective spares management reduces MTTR and protects production continuity by ensuring parts are available at the right time.

Maintenance Management: Breakdown, Preventive & Predictive Maintenance, TPM, Reliability and Maintenance Planning (Basics)

8 more questions to unlock