Material Handling is an inseparable part of plant layout. Methods study, plant layout, and material handling are all components of the design of a production facility. There are more than 430 different types of material handling equipment, and each type is represented by 6 to 10 major manufacturers.
Material Handling (MH) is the handling of materials. The extent of MH activity in a company depends on the type of company, its product, the size of the company, the value of the product, the relative importance of handling to the enterprise, etc.
According to Material Handling Society, MH is the art and science involving the movement, packaging and storing of substances in any form.
In industries, various products are manufactured. During manufacture, materials move from
• one operation to another
• one machine to another
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• one department to another
• one workstation to another
• stores to workstation
• workstation to stores, and so on.
Although, MH is an unproductive work, it is an essential and unavoidable activity in an industrial environment. MH cost is an overhead cost which must be kept as low as possible to get the maximum profit. MH cost can vary from 20 to 60 % of the total production cost. A component may be handled 50 times or more before it becomes part of the final product. it is also estimated that 35 to 40 % of the plant accidents are due to bad method of material handling.
3.6.1 PRINCIPLES OF MATERIAL HANDLING These are narrated as follows:
1. Orientation principle: Study the problem thoroughly before preliminary planning to identify existing methods and problems, physical and economic constraints, and to establish future require- ments and goals.
2. Planning principle: Establish a plan to include basic requirements, desirable options, and the consideration of contingencies for all material handling and storage activities.
3. Systems principle: Integrate those handling and storage activities that are economically viable into a coordinated system of operations, including receiving, inspection, storage, production, assembly, packaging, warehousing, shipping, and transportation.
4. Unit load principle: Handle product in as large a unit load as possible.
5. Space utilization principle: Make effective utilization of all cubic space.
6. Standardization principle: Standardize handling methods and equipment wherever possible.
7. Ergonomic principle: Recognize human capabilities and limitations by designing material handling equipment and procedures for effective interaction with the people using the system.
8. Energy principle: Include energy consumption of the material handling systems and material handling procedures when making comparisons or preparing economic justifications.
9. Ecology principle: Use material handling equipment and procedures that minimize adverse effects on the environment.
10. Mechanization principle: Mechanize the handling process where feasible to increase effi- ciency and economy in the handling of materials.
11. Flexibility principle: Use methods and equipment that can perform a variety of tasks under a variety of operating conditions.
12. Simplification principle: Simplify handling by eliminating, reducing, or combining unnec- essary movements and/or equipment.
13. Gravity principle: Utilize gravity to move material wherever possible, while respecting limi- tations concerning safety, product damage, and loss.
14. Safety principle: Provide safe material handling equipment and methods that follow existing safety codes and regulations in addition to accrued experience.
15. Computerization principle: Consider computerization in material handling and storage systems, when circumstances warrant, for improved material and information control.
16. System flow principle: Integrate data flow with physical material flow in handling and storage.
17. Layout principle: Prepare an operation sequence and equipment layout for all viable system solutions, then select the alternative system that best integrates efficiency and effectiveness.
Layout Planning 59 18. Cost principle: Compare the economic justification of alternative solutions in equipment and methods on the basis of economic effectiveness as measured by expense per unit handled.
19. Maintenance principle: Prepare a plan for preventive maintenance and scheduled repairs on all material handling equipment.
20. Obsolescence principle: Prepare a long-range and economically sound policy for replace- ment of obsolete equipment and methods with special consideration to after-tax lifecycle costs.
3.6.2 SIMPLIFIED VERSION OF PRINCIPLES OF MATERIAL HANDLING 1. Eliminate material handling as much as possible by proper layout.
2. Make accurate and complete analysis of the present and future costs of MH.
3. Use various techniques to develop the MH system in plant.
4. Avoid handling of materials by the direct labor specially skilled ones.
5. Avoid using handling equipment below its capacity.
6. Move materials in containerized units (e.g., small milk tins in a box, small cups and plates in a tray, or soft drink bottles in a crate) rather than as a single item.
7. Move materials at a higher speeds and in larger quantity.
8. Use the space effectively for storing and moving materials.
9. Use gravity flow of materials wherever possible.
10. Reduce the distance traveled by materials by proper layout.
11. Avoid backtracking of materials.
12. Avoid rehandling of materials which may spoil the quality (like non-sticking utensils, etc).
13. Choose the right type of MH equipment:
• For small items (soaps, tea bags, tooth pastes, etc.) - Use boxes.
• For medium size items (boxes, cartons, tins, etc.) - Use hand trucks.
• For large size items ( lathe machine components, auto parts, etc) - Use overhead cranes.
14. Standardize the MH equipment.
15. Combine the movement and storage of materials.
16. Combine the movement and operations to be performed on materials.
17. Provide safety in the plant while handling materials.
18. Avoid unnecessary mixing of materials.
19. Maintain the MH equipment regularly to avoid breakdowns.
20. Keep gangway clean.
21. Create a separate organization for MH.
22. Train the operators in MH.
23. Plan MH for overall economy.
3.6.3 MATERIAL HANDLING EQUIPMENT 1. Conveyors
• Belt conveyors—airport baggage handling
• Chain/cable conveyors—coal mines
• Gravity roller conveyors—power plant coal handling system
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• Live roller conveyors—Petroleum companies
• Elevating conveyors—fertilizer factories
• Screw/spiral conveyors—cement factories
• Pipeline conveyors
• Chutes 2. Cranes
• Fixed cranes—steel factory
• Travelling cranes—turbine shop
• Electric hoist—automobile factories
• Winches and capstans 3. Mobile
• Industrial vehicles
• Fixed platform type
• Lift platform type—to transport bricks, books, etc.
• Fork lift trucks
• Motor vehicles or trucks—to transport petroleum products
• Rail road cars or goods train—to transport coal, ores, sheet, rods, etc.
• Cargo ships—to carry oil, food supply, etc.
• Cargo planes—to transport passengers’ baggage, equipment, etc.
3.6.4 RELATIONSHIP BETWEEN MATERIAL HANDLING AND FACTORY BUILDING DESIGN OR LAYOUT
• MH and plant layout are very closely related. An effective layout involves least material handling and less costly MH equipment. It also allows material handling without any loss of time, with minimum delays and least back-tracking.
• The total number of movements and the distances moved in one step are also reduced considerably in a properly designed plant layout.
• In a poorly planned layout, the width of aisle or sub-aisle, and ceiling heights may be inadequate to accommodate MH equipment.
• In a well designed plant layout, MH is minimized. Space requirements are considerably reduced. Material movements are much faster and more economical. Bottlenecks and points of congestion are reduced. Machines and workers do not remain idle due to lack of materials.
Production line flow becomes smooth.
• For minimum MH, the location of store rooms, tool rooms, lavatories, offices, test floors, shipping, wrapping centers, etc should be judiciously made.
In making equipment layout, the following points should be taken into account:
• Provide aisles (passages) wide enough to accommodate the latest types of mobile MH equip- ment.
• Keep work at a convenient working level.
• To conserve floor space, use overhead means of conveying and storage.
• Plan first operations nearer to the point of receiving.
• Use yard storage if materials do not need protection from weather.
Layout Planning 61
• Provide proper lights and ventilation in MH area.
• Consider mechanical assistance when workmen
• Must lift more than 36 kgs, or a female worker has to lift more than 18 kgs of load.
• Must handle the same materials for more than 30 minutes.
• Must move materials for a distance of over 50 feet.
• Are exposed to unusual safety hazards.
REFERENCE
1. H B Maynard Industrial Engineering Hand Book.
2. Philip E. Hicks, Industrial Engineering and Management: A New Perspective, McGraw-Hill International Editions, 1994.
Purchasing Systems and Vendor Rating
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4.0 INTRODUCTION
Most manufacturing organisations spend more than 60% of their money for materials, i.e., materials soak up a substantial portion of the capital invested in an industrial concern. This emphasizes the need for adequate materials management and control because even a small saving in materials can reduce the production cost to a significant extent and thus add to the profits. Materials Management may be thought of as an integrated functioning of the different sections of a company dealing with the supply of materials and other related activities so as to obtain maximum co-ordination and optimum expenditure on materials etc., used in an industrial concern.