UNIT - 4

2 MARK QUESTIONS

Maintenance Management

A26. What is maintenance? P 444

            Maintenance is a function of production management that is cocerned with day to day problems of keeping the physical plant in good working condition.

A27. What is Maintenance management?  P444

            Maintenance management is concerned with planning organising, and directing resources in order to control the availability and performance of the industrial plants to some specified level.

A28. List the common types of maintenance? P447

            1. Breakdown maintenance, 2. Preventive maintenance, 3. Predictive maintenance, 4. Planned maintenance, and 5. Routine maintenance

A29. What is Preventive Maintenance? P447

            Preventive maintenance  covers all activities undertaken before the machine or equipment fail. It aims to minimise the possibility of unanticipated or major breakdowns.

A30. What is Planned Maintenance? P448

            Planned maintenance covers all maintenance activities that are carried out according to a predetermined schedule. It is also known as scheduled maintenance or productive maintenance.

A31. What is breakdown maintenance? P 447

                Break down maintenance is corrective or remedial maintenance that occurs when equipment or machines fail and must be repaired on an urgent basis.

B 9. Mention any four questions the Maintenance Planning tries to answer?  P 450

            Maintenance planning seeks to answer the following questions

1.    What maintenance activities are to be carried out/

2.    How these activities are to be carried out?

3.    Where these activities are to be performed?

4.    Why these activities are to be performed

5.    When these activities are to be performed?

Statastical Quality Control

A32 What is ‘Statistical Quality Control’ ? P 394

            Statistical quality control is the application of statistical techniques to accept ot reject a product already produced or to control the process while it is being carried out.

A33. What is ‘Acceptance Sampling’?  P395

            Acceptable sampling is a statistical technique used to take a decision regarding acceptance or rejection of a lot without having to examine the entire lot, based on the quality of a sample.

A34. What is the difference between ‘variable’, and ‘attribute’ in SQC?  P 391

            Variable is quality characteristic which can be measured, and attribute is quality characteristic which cannot be measured but can be described as good or bad, acceptable or unacceptable.

B 10. Define quality of Product/Service.  P388

            Quality is the sum total features of a product which influence its ability to satisfy a given demand.

               

B 11. What is inspection?  P388

            Inspection is the verification of conformance of goods or services to the design specifications.

B 12.  List any two control charts used for variables? P398

            Xbar chart and R chart

B13.  List any two control charts used for attributes? P398

            Np chart, p chart, c chart, u chart

C6. Define ‘Variable’  P 397 Box 17.1

            Variables are quality characteristics that can be measured on a continuous scale eg. the length of a part.

C7. Define ‘Attribute’ P 397 Box 17.1

            Attributes are quality characteristics which can be classified into one of the two categories eg good or bad, OR  acceptable or unacceptable. Eg. painted surface is good or bad based on finish.

                                              8 MARK QUESTIONS

Maintenance Management

A 10. List the four major maintenance methods , and describe them in brief. P 447-8

                The four major maintenance methods are – 1. Break down maintenance, 2. Preventive maintenance, 3. Predictive maintenance, and  4. Planned maintenance.

            Break down maintenance, as the name suggests, is undertaken after a machine stops working because of breakdown.  Maintenance actually becomes repair work. The work undertaken varies from band aid to total overhaul.

            Preventive maintenance in contrast is undertaken to prevent a machine failure, and also to increase the gap between two successive breakdowns. The aim is to minimize the possibility of unanticipated stoppage of a machine. It is done by maintaining the machine clean, and by regular inspection and lubrication of all moving parts. It also involves changing parts or oils at fixed intervals.

            Planned maintenance – Breakdowns do not occur as planned but maintenance can be planned well in advance.  Inspection reports give enough advance indication of impending problems. All repair works relating to the problem are planned in advance and undertaken during weekends, or on holidays to prevent work stoppages.

            In Predictive maintenance, sensitive instruments like vibration recorders, temperature monitors, amplitude meters etc are used to monitor the condition of an equipment and planned maintenance is carried out when any breakdown become imminent, based on the data provided by the instruments. 

A 11. What are the objectives of maintenance management? P 446

                The objectives of maintenance management are

1.      Minimising loss of production due to breakdowns.

2.      Minimising repair time and repair cost.

3.      Efficient use of maintenance personnel and equipment.

4.      Prolonging life of capital assets by minimizing the rate of wear and tear.

5.      To keep all productive assets in good working condition.

6.      Maximise efficiency and economy in production.

7.      Minimise total maintenance costs.

8.      Minimise accidents.

9.      Improve quality of products.

B 8. Describe the importance of maintenance Management.  P 445

1.  To establish competitive edge , companies must have equipment in reliable condition to respond to customer demand when needed.

2.  Inconsistencies in equipment causes, variation in product characteristics, and result in defective parts.

3.  Good maintenance management is important for companies cost control. As the companies go for automation and costlier equipment, keeping them in good working condition longer becomes important.

4.  Just in time procurement of materials, and product layouts do not leave much lee way for delays caused by machine stoppages. Besides  the idle labour and idle other related equipment, the permanent loss of market share can be avoided by good maintenance management.

5.  Organisations like airlines, oil refineries invest huge amounts in equipment and results of any equipment failure, can be disastrous.

C 7. How do companies control the maintenance costs?  P452-453

            To control the maintenance costs, companies do the following.

1.      All maintenance works are authorised by responsible official.

2.      Maintenance schedules are prepared stipulating the timing and manpower required.

3.      All materials needed for maintenance are issued from stores against proper authorisation from maintenance dept.

4.      Maintenance budgets are prepared and got approved by top management. Actual expenses incurred are checked against the budgets.

5.      Proper records of all maintenance done are maintained.

6.      Maintenance plans are periodically reviewed, for their effectiveness.

C 8. What are the steps in maintenance planning? p 451

Maintenance planning has the following steps.

1.      Classify all the equipment into vital, important and necessary equipment. The plans will  be different for each group.

2.      Classify maintenance activities, based on emergencies, priority and non-priority work.

3.      Create a grid, based on the above data, and establish priorities.

4.      Estimate the time needed for all the work involved.

5.      Estimate all the materials needed, tools and manpower needed for each activity.

6.      Develop a repair plan and draw a PERT chart to minimize the time taken.

7.      Get the approval of top management. If necessary rework the plan to incorporate the constraints the management may impose.

8.      Ensure all materials needed are ordered and received in time.

9.      Draw all materials needed before starting the work.

Statastical Quality Control

A 12. Describe the stages of production activities where  inspection is done?  P 392

                The different stages at which quality inspection is done are

1.      Raw materials and purchased parts – supplied by outside vendors are to be inspected.

2.      Finished products – before being sent to finished goods godown, are inspected. A defective product reaching customer can badly damage the reputation of the company.

3.      Before a costly operation – to ensure time of costly machine Is not spent on defective part.

4.      Before an irreversible process – as a processed product cannot be reworked.

5.      Before surface finish operation – as cracks and surface defect cannot be observed after painting.

A 13. List the benefits of Quality Control.  P 392

                The benefits of Quality Control are

1.      Minimise scrap or rework due to reduced defectives.

2.      Reduced cost of labour and materials.

3.      Reduced customer complaints.

4.      Increased quality consciousness among employees.

5.      Higher operating efficiencies.

6.      Better utilization of resources.

7.      Better employee satisfaction and customer satisfaction.

B 9. What are the Objectives of Inspection?  P 389

                The objectives of Inspection are

1.      Prevention of defects.

2.      Detect defects as they occur in processing

3.      Detect trends in the process which may lead to defects.

4.      Remove defective parts from further processing

5.      Remove defective parts to prevent poor performance of finished product.

6.      Maintain records for evaluation of performance of each machine and worker.

7.      Inform to all levels of management , the performance of equipment.

B 10. List different dimensions of Product Quality.  P388

            The different dimensions of the product quality are

1.      Performance- to meet the customer expectations

2.      Features - special,characteristics that appeal to customers.

3.      Reliability - Reduced likelihood of breakdowns, malfunctioning, or need for repairs.

4.      Serviceability - The speed cost and convenience of repair and maintenance. Higher the serviceability, better is the quality.

5.       Appearance - Affect on human senses. - look, colour, smell, sound etc.

6.      Safety - in usage.

7.      Customer service - pleasant and prompt

C 9. List the different control charts used to control quality   P 398  Box 17.2

                The quality characteristics are grouped into two namely attributes and variables. Different charts are used to control the limits of these characteristics.

            For Variables – X bar chart and R chart ( mean and range chart)are used

            For Attributes- four charts are used namely –

1.      np chart - number of defectives chart for  constant sample size

2.      p chart - fraction defective chart for varying sample size

3.      c chart - number of defects for all samples in each subgroup chart  and

4.      u chart - number of defects per unit chart for varying sample size.

                                    15 MARK QUESTIONS

Maintenance Management

Statastical Quality Control