Material Handling:-
Materials handling can be also defined as ‘the function dealing with the preparation, placing and positioning of materials to facilitate their movement or storage’. Material handling is the art and science involving the movement, handling, and storage of materials during different stages of manufacturing. Thus the function includes every consideration of the product except the actual processing operation. In many cases, handling is also included as an integral part of the process. Through scientific material handling considerable reduction in the cost as well as in the production cycle time can be achieved.
OBJECTIVES OF MATERIAL HANDLING Following are the objectives of material handling:
1. Minimise the cost of material handling.
2. Minimise delays and interruptions by making available the materials at the point of use at the right quantity and at right time.
3. Increase the productive capacity of the production facilities by effective utilization of capacity and enhancing productivity.
4. Safety in material handling through improvement in working conditions.
5. Maximum utilization of material handling equipment.
6. Prevention of damages to materials.
7. Lower investment in process inventory.
PRINCIPLES OF MATERIAL HANDLING Following are the principles of material handling:
1. Planning principle: All handling activities should be planned.
2. Systems principle: Plan a system integrating as many handling activities as possible and co-ordinating the full scope of operations (receiving, storage, production, inspection, packing, warehousing, supply, and transportation).
3. Space utilization principle: Make optimum use of cubic space.
4. Unit load principle: Increase quantity, size, the weight of load handled.
5. Gravity principle: Utilise gravity to move a material wherever practicable.
6. Material flow principle: Plan an operation sequence and equipment arrangement to optimize material flow.
7. Simplification principle: Reduce combine or eliminate unnecessary movement and/or equipment.
8. Safety principle: Provide safe handling methods and equipment.
9. Mechanisation principle: Use mechanical or automated material handling equipment.
10. Standardisation principle: Standardise method, types, size of material handling equipment.
11. Flexibility principle: Use methods and equipment that can perform a variety of tasks and applications. 12. Equipment selection principle: Consider all aspects of the material, move, and method to be utilized.
13. Deadweight principle: Reduce the ratio of dead weight to the payload in mobile equipment.
14. Motion principle: Equipment designed to transport material should be kept in motion.
15. Idle time principle: Reduce idle time/unproductive time of both MH equipment and manpower.
16. Maintenance principle: Plan for preventive maintenance or scheduled repair of all handling equipment.
17. Obsolescence principle: Replace obsolete handling methods/equipment when more efficient method/equipment will improve operation.
18. Capacity principle: Use handling equipment to help achieve its full capacity.
19. Control principle: Use material handling equipment to improve production control, inventory control, and another handling.
20. Performance principle: Determine the efficiency of handling performance in terms of cost per unit handled which is the primary criterion.
SELECTION OF MATERIAL HANDLING Equipment:- Selection of Material Handling equipment is an important decision as it affects both the cost and efficiency of the handling system. The following factors are to be taken into account while selecting material handling equipment.
1. PROPERTIES OF THE MATERIAL Whether it is solid, liquid or gas, and in what size, shape, and weight it is to be moved, are important considerations and can already lead to a preliminary elimination from the range of available equipment under review. Similarly, if the material is fragile, corrosive, or toxic this will imply that certain handling methods and containers will be preferable to others.
2. LAYOUT AND CHARACTERISTICS OF THE BUILDING Another restricting factor is the availability of space for handling. The low-level ceiling may preclude the use of hoists or cranes, and the presence of supporting columns in awkward places can limit the size of the material-handling equipment. If the building is multi-storeyed, chutes or ramps for industrial trucks may be used. The layout itself will indicate the type of production operation (continuous, intermittent, fixed position, or group) and can indicate some items of equipment that will be more suitable than others. Floor capacity also helps in selecting the best material handling equipment.
3. PRODUCTION FLOW If the flow is fairly constant between two fixed positions that are not likely to change, fixed equipment such as conveyors or chutes can be successfully used. If, on the other hand, the flow is not constant and the direction changes occasionally from one point to another because several products are being produced simultaneously, moving equipment such as trucks would be preferable.
4. COST CONSIDERATIONS This is one of the most important considerations. The above factors can help to narrow the range of suitable equipment, while costing can help in making a final decision. Several cost elements need to be taken into consideration when comparisons are made between various items of equipment that are all capable of handling the same load. Initial investment and operating and maintenance costs are the major cost to be considered. By calculating and comparing the total cost for each of the items of equipment under consideration, a more rational decision can be reached on the most appropriate choice.
5. NATURE OF OPERATIONS Selection of equipment also depends on the nature of operations like whether handling is temporary or permanent, whether the flow is continuous or intermittent, and material flow pattern-vertical or horizontal.
6. ENGINEERING FACTORS Selection of equipment also depends on engineering factors like door and ceiling dimensions, floor space, floor conditions, and structural strength.
7. EQUIPMENT RELIABILITY Reliability of the equipment and supplier reputation and the after-sale service also plays an important role in selecting material handling equipment.
MATERIAL HANDLING equipment: Broadly material handling equipment’s can be classified into two categories, namely: (a) Fixed path equipment, and (b) Variable path equipment
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(a) Fixed path equipment which moves in a fixed path. Conveyors, monorail devices, and pulley drive equipment belong to this category. A slight variation in this category is provided by the overhead crane, which though restricted, can move materials in any manner within a restricted area under its design. Overhead cranes have a very good range in terms of hauling tonnage and are used for handling bulky raw materials, stacking, and at times palletizing.
(b) Variable path equipment have no restrictions in the direction of movement although their size is a factor to be given due consideration trucks, forklifts mobile cranes and industrial tractors belong to this category. Forklifts are available in many ranges, they are maneuverable and various attachments are provided to increase their versatility. Material Handling Equipment may be classified into five major categories
1. CONVEYORS are useful for moving material between two fixed workstations, either continuously or intermittently. They are mainly used for continuous or mass production operations—indeed, they are suitable for most operations where the flow is more or less steady. Conveyors may be of various types, with rollers, wheels, or belts to help move the material along: these may be power-driven or may roll freely. The decision to provide conveyors must be taken with care since they are usually costly to install; moreover, they are less flexible and, where two or more converge, it is necessary to coordinate the speeds at which the two conveyors move.
2. INDUSTRIAL TRUCKS are more flexible in use than conveyors since they can move between various points and are not permanently fixed in one place. They are, therefore, most suitable for intermittent production and for handling various sizes and shapes of material. There are many types of truck petrol-driven, electric, hand-powered, and so on. Their greatest advantage lies in the wide range of attachments available; these increase the truck's ability to handle various types and shapes of material.
3. CRANES AND HOISTS The major advantage of cranes and hoists is that they can move heavy materials through overhead space. However, they can usually serve only a limited area. Here again, there are several types of crane and hoist, and within each type, there are various loading capacities. Cranes and hoists may be used both for intermittent and for continuous production.
4. CONTAINERS These are either ‘dead’ containers (e.g. Cartons, barrels, skids, pallets) that hold the material to be transported but do not move or ‘live’ containers (e.g. wagons, wheelbarrows, or computer self-driven containers). Handling equipment of this kind can both contain and move the material and is usually operated manually.
5. ROBOTS - Many types of robots exist. They vary in size, and in function, and maneuverability. While many robots are used for handling and transporting material, others are used to perform operations such as welding or spray painting. An advantage of robots is that they can perform in a hostile environment such as unhealthy conditions or carry on arduous tasks such as the repetitive movement of heavy materials.
GUIDELINES FOR EFFECTIVE UTILISATION OF MATERIAL HANDLING equipment The following guidelines are invaluable in the design and cost reduction of the materials handling system:
1. As material handling adds no value but increases the production cycle time, eliminate handling wherever possible. Ideally, there should not be any handling at all!
2. Sequence the operations in a logical manner so that handling is unidirectional and smooth.
3. Use gravity wherever possible as it results in the conservation of power and fuel.
4. Standardize the handling equipment to the extent possible as it means interchangeable usage, better utilization of handling equipment, and lesser spares holding.
5. Install a regular preventive maintenance program for material handling equipment so that downtime is minimal.
6. In the selection of handling equipment, criteria of versatility and adaptability must be the governing factor. This will ensure that investments in special purpose handling equipment are kept at a minimum.
7. Weight of the unit load must be maximum so that each ‘handling trip’ is productive.
8. Work-study aspects, such as elimination of unnecessary movements and a combination of processes should be considered while installing a material handling system.
9. Non-productive operations in handling, such as slinging, loading, etc., should be kept at a minimum through the appropriate design of handling equipment. Magnetic cranes for scrap movement and loading in furnaces combination of excavators and tippers for ores loading and unloading in mines are examples in this respect.
10. Location of stores should be as close as possible to the plant which uses the materials. This avoids handling and minimizing investment in material handling systems.
11. Application of OR techniques such as queueing can be very effective in optimal utilization of materials handling equipment.
12. A very important aspect in the design of a material handling system is the safety aspect. The system designed should be simple and safe to operate.
13. Avoid any wasteful movements-method study can be conducted for this purpose.
14. Ensure proper coordination through judicious selection of equipment and training of workmen.
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