2 MARK QUESTIONS
Material Handling
A.21. What do understand by ‘material handling’? P515
Material handling is the art and science of moving , packing, and storing of substances in any form.
A 22. What is unit load concept in material handling? P518
Unit load refers to the number of items so arranged that this mass can be picked and moved as a single object. It is based on the principle that it is quicker to move a lot of items as a unit than to move each item individually.
B 5. List any four objectives of material handling? P 516
The objectives of materials handling are
1. Achieving lower unit material handling costs.
2. Reduction in manufacturing cycle time through faster movement of materials.
4. Improved working conditions and greater safety.
5. Avoiding damage to materials by inefficient handling
6. Increased storage capacity by better utilization of storage space.
7. Higher productivity and lower costs.
B 6. What factors affect the selection of material handling equipment? P521
Production problem, capabilities if handling equipment available, and human element are the main factors affecting selection of materials handling equipment.
C 2. List any two types of conveyor systems. P523
The different types of conveyor systems are – belt conveyor, chain conveyor, roller conveyor, and pneumatic conveyer.
C3. List any two types of material handling systems that are used for moving materials vertically? P 523
The types of material handling systems that are used for moving materials vertically are – cranes, elevators, hoists, winches etc.
Work Study
A23. Define work study P 172
Work study is the generic term used for those techniques , particularly method study and work measurement , which are used in the examination of any work , and which will lead to effecting improvement.
A 24. What do you understand by ‘ Method Study’? P123 table 10.1
The systematic recording and critical examination of existing and proposed ways of doing work as a means of developing and applying easier and more effective methods and reducing human effort and costs.
A 25. What do you understand by ‘ Time Study’? P123 table 10.1
A technique of work measurement used for determining as accurately as possible, from a limited number of observations, the time necessary to carry out a given activity at a defined standard of performance. A stopwatch is used for the purpose of recording the actual time taken by the worker under observation, to perform various elements of the work.
B 7. What do you understand by ‘ Work Measurement’? P123 table 10.1
Work measurement is the application of techniques designed to establish the time for a qualified worker to carry out a specific job at a defined level of performance.
B 8. What is Work Sampling’ P192
Work sampling is a work measurement technique that randomly samples the work of one or more employees at periodic intervals to determine the efficiency at which the workmen are operating.
C4. What do you understand by ‘ Work Simplification’? P123 table 10.1
Work simplification involves analysis and bringing in improvements in work methods, or work flows, so that work can be done at a lesser cost or with lesser effort.
C5. List techniques of ‘ Work measurement’ P184
Different techniques of work measurement are 1. Direct time study, 2. Synthetic method, 3. Analytical estimating 4. Predetermined motion time systems, and 5. Work sampling
8 MARK QUESTIONS
Material Handling
A 7. List the Principles of Material Handling. P517 Table 22.1
1. Materials should move through the facility in direct flow patterns, minimising zig-zagging or backtracking
2. Mechanised material handling devices should be designed and located so that human effort is minimised.
3. The number of times a material is handled should be minimised.
4. Heavy and bulk material should be moved as less as possible during processing.
5. Mobile equipment should carry full loads all the times.
6. Should be flexible to adjust to changing production needs, and breakdown of material handling equipment.
C 4. List the types of material handling systems along with their classification. P 522
The material handling systems can be classified according to the type of handling equipment used, type of material handled, and the methods, need or function performed.
The classifications are
1. Equipment oriented systems – i) overhead systems ,ii) conveyor systems , iii)tractor transfer systems, iv) fork lift truck and pallet truck systems, v) industrial truck systems, vi) underground systems.
2. Material oriented systems – i) unit handling systems , ii) bulk handling systems, iii) liquid handling systems
3. Method oriented systems- i)manual systems, ii) mechanised or automated systems, iii)job shop handling systems, iv) Mass production handling systems.
4. Function oriented systems – i) transport systems, ii) conveying systems, iii) transferring systems, iv) elevating systems.
A 8. Describe the different kinds of material handling systems used for moving materials horizontally and vertically ? P 523
The major group of equipment used to move material horizontally are – conveyors. Conveyors are of various types
1. Belt conveyors – motor driven, usually rubberized cotton or metal fabric. Used for both short distance or long distance, for movement of large quantity of materials.
2. Chain conveyors – motor driven, drags materials along a metal sliding support.
3. Roller conveyor – Boxes or large items are moved over rollers using gravity for movement.
4. Pneumatic conveyors – High volume of air moves through a tube carrying with it the materials, mostly in powdery form.
5. Other types of conveyors are vibratory conveyors etc. for moving materials over short distances.
The group of equipment used to move material vertically are – cranes, elevators and hoists.
1. Cranes are normally used to lift heavy materials. Over head gantry cranes move over rails across factory. Tyre mounted or track mounted cranes can lift very heavy loads, and move over very short distances.
2. Elevators are a type of cranes that usually lift materials between floors of a building.
3. Hoists move materials vertically and horizontally over a very limited area. Eg forklift trucks, electric hoists.
C 5. What are the characteristics that you would look at while selecting suitable material handling systems? P 521-22
While selecting material handling systems, I look at the following factors.
1. Adaptability
2. Flexibility to handle different materials.
3. Adequate load capacity
4. Powerful
5. Good Speed
6. Low space requirement to move around
7. Lower supervision required
8. Ease of maintenance
9. Environmental regulation
10. Cost of equipment
Work Study
A 9. An 8 hour work measurement study, reveals the following,
Units produced = 320; idle time = 12% ; performance rating = 120% ; allowances = 15% of normal time. Determine the standard time. (Worked out example No 2 Page 199)
Ans. Working time = Shift time - Idle time
= 480-480*.15
= 408 minutes
Observed time for unit = 408 / 320 = 1.275 minutes
Normal time = observed time * observed rating/100
= 1.275*120/100 = 1.53 minutes
Standard time per unit = normal time = allowances = 1.53 + 1.53*.12
= 1.714 minutes.
B 6. What are the benefits of Work Study. P 173
The benefits of work study are
1. Increased productivity and operational efficiency
2. Reduced manufacturing costs.
3. Improved workplace layout
4. Better manpower planning
5. Better capacity planning
6. Better working conditions.
7. Improved work flow.
8. Reduced material handling costs.
9. Provides basis for measuring labour efficiency.
10. Is the Basis for sound incentive schemes.
B 7. Describe the method study procedure. P 177-178
The method study procedure is as follows
1. Select the work to be studied based on parameters like - excessive cost, long time taken for the job, high rate of accidents, high rate of rejection, excessive movement of materials.
2. Record all the relevant facts pertaining to the existing method using recording techniques like different process charts and diagrams.
3. Examine the recorded facts critically, challenging everything being done
4. Develop an improved method.
5. Install the improved method , including training workmen in the new method.
6. Maintain the new method, by constant monitoring for some time.
C 6. Describe the questioning attitude of Method Study P178 Box 10.1
The questions that are asked during the method study are
1. What is being done? What is the purpose of the operation? Why should it be done? What happens if it is not done? Is every part of operation necessary?Can any of them eliminated? Can any of them modified or simplified so that the work can be done with less effort or in less time?
2. Who does the work? Why this person? Who could do it better? Can a less skilled person do the job?
3. Where is the work done? Why is it done there only? Could it be done somewhere else economically?
4. When is the work done? Why should it be done only then? Can it be done better at some other time?
5. How is the work done? Is it the only way it can be done? Are there better ways of doing it?
15 MARK QUESTIONS
Material Handling Systems
C 3. What are the major factors that affect the selection of material handling systems? P 521-22
Selection of material handling systems requires attaining a balance between the following
1. Production problem
2. Capabilities of material handling equipment
3. Human element involved
The production problems are
1. Volume of production to be achieved
2. Type of material to be handled
3. Layout of plant and building facilities.
The equipment factors are
1. Adaptability
2. Flexibility to handle different materials.
3. Adequate load capacity
4. Powerful
5. Good Speed
6. Low space requirement to move around
7. Lower supervision required
8. Ease of maintenance
9. Environmental regulation
10. Cost of equipment
Human factors are
1. Capabilities of available manpower.
2. Safety of personnel
A 5. List in tabular form the long term and short term maintenance activities and their sources of information? P452 Box 18.1
Time schedule for maintenance activities
Time schedule
|
Maintenance Activities
|
Sources of Information
|
Long Term
|
Lubrication
|
Manufacturer’s recommendation
|
Short term
|
Preventive maintenance – inspection
|
Technical experience, and maintenance manual
|
overhauling
|
Machine history record
| |
Cleaning
|
Maintenance Manual
| |
Replacement of machine
|
Techno economic evaluation
| |
Replacement of parts
|
Inspection reports
Complaints of break down
Analysis of history of break downs
Techno economic evaluation
| |
Work Study
C5. List the principles of Motion Economy P 182 Box 10.2
The principles of motion economy are divided into three groups.
1. Effective use of operator
2. Arrangement of the work place
3. Tools and equipment
Effective use of operator / human body
1. Both hands should begin and end the motion at the same time.
2. Motion of the hands should be in the opposite and symmetrical direction.
3. Hands and body movement should be confined to lowest classification so as to perform the work satisfactorily. The classification according to motion are a) fingers only b) fingers and wrists, c) fingers wrist and lower arm, d) fingers wrists lower and upper arms, e) hands arms and body
4. Smooth, continuous, and curved motion of the hands is preferable.
5. The two hands should not be idle at the same time except at rest.
6. Momentum should be employed to assist the worker.
7. Eye fixation should be as free and as close as possible.
Rules concerning arrangement of work place.
1. There should a definite and fixed place for all tools and materials.
2. Tools and materials should be located close to the point of use.
3. Gravity feed should be used to deliver materials close to the point of use.
4. Good illumination is the primary requirement of satisfactory visual perception.
5. He height of the work bench and chair should be such that alternate shifting and standing at work is easily possible
6. Chair of the type and height to permit good posture should be provided to each worker.
Rules concerning design of tools and equipment
1. Hands should be relieved of all work that can be done by a jig or fixture or a foot operated device.
2. Two or more tools should be combined wherever possible.
3. Tools and materials should be prepositioned wherever possible.
4. Levers hand wheels, and crossbars should be positioned in such a way that operator can manipulate them with least change in body position, and with greatest mechanical advantage.
B2. Describe the method study procedure. P 177-178
The various steps involved in method study are
Select the work to be studied based on –maximum economic advantage arrived, excessive material handling involved, frequent accidents .
Record all relevant facts or information pertaining to the existing method , using the following techniques.
Process charts -
1. outline process chart,
2. operation process chart,
3. Flow process chart – material type, man type, and machine type.
4. Man- machine chart
5. Two handed process chart
6. Multiple activity chart
7. Simultaneous motion chart
8. Motion chart
9. Film analysis chart
Diagrams such as
1. Flow diagram
2. String diagram
3. Cycle diagram
4. chronocycligraph
Examine the recorded facts critically challenging everything being done, seeking alternatives, questioning the purpose, the means, sequence, place, and the person etc.
Develop an improved method by generating several alternatives, and selecting the best method.
Install the improved method in three phases – planning, arranging and implementing phases.
Maintain the new method by ensuring that the installed method is functioning well.
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