Material Handling

Material Handling (MH) Introduction •MH includes any or all movements, packaging and storage of materials, parts, assemblies, and products •Term materials include raw materials, parts, subassemblies, and semi-finished goods • Need of handling of goods between plants (transportation) •MH includes all such movements of materials from the receipt of the raw materials to the shipment of finished products. •MH is a system which forms the various factors of movement, transfer, warehousing, in-process handling, and shipping into one interdependent cycle considering the most economical solution for the respective plant. The next slide demonstrates the material handling system in the form of flow diagram.

Materials Flow Diagram MH system in the form of Flow Diagram: Raw mat. supplier

Transportation

Receiving at store

Manufacturing/fabrication units

Storing

Flow of parts to assembly line

shipping

Disposal/ recycling

Testing and packaging Dealers/consumers

Warehouse

Material handling in intermittent and continuous manufacturing system • In some operations, MH cost can be reduced by accumulating parts between operations • This condition is true for intermittent system where less automation of MH system. • Parts can be accumulated and inventoried in to the boxes or baskets and transported by hand-jack dollies or forklift trucks more economically than they can be carried by hand. • In continuous manufacturing, automated MH system are designed to reduce overall handling costs, resulting in less work in process (Reference: Rverette E. Adam, Ronald J. (2001). Production and Operations Management, p. 456)

Functions of material handling • The movement and positioning of purchased materials for storage • Internal transportation of materials from store to shops or as required • Movement of materials from one department to another or from one machine to another • Movement of finished products to store or sale • Unloading raw materials • Loading packed materials to move

Factors to be considered in material handling problem

1 Engineering factors

2 Economic factors Engineering factors to be considered: • Nature of materials and products (solid, gas, etc) • Production process and equipment (sequence of operation, machine output per unit time) • Building construction (single or multi-storey) • Layout (layout and material handling are not separable) • Existing material handling equipment • Production planning and control (sequence for material flow and timing for processing) • Packaging (easy handling of packaged products)

Economic factors to be considered in MH… • • • • • • • •

Initial cost of equipment Cost of installation Rearrangement of present equipment Cost of alternation necessary to the building Cost of maintenance, repairs, supplies etc Cost of power, depreciation Cost of labor to operate Cost of auxiliary equipment (for example, charging equipment for truck batteries, etc)

Flexible MH equipment help in reducing operating costs.

Basic principles of MH • Reduction in handling (minimize MH) • Reduction in time (waiting, loading, traveling time) • Principles of unit load (not one piece but optimum number of pieces as a unit) • Use of gravity (cheapest source of motive power) • Safety • Use of containers • Stand by facility • Periodical check up • Avoid interference with production line • Flexibility (necessary changes are incorporated)

Material handling devices 1. Lifting and lowering devices (vertical movement) 2. Transporting devices (horizontal movement) 3. Devices with lift and transport (combination devices) 4. Industrial Robots 5. Automatically guided vehicles

1 Types of Lifting and lowering devices • Block and tackle (lifting vertically) • Hand and power winches • Hoists (lifting load vertically) • Elevators √ • Pillar crane (stationary or mobile type) • Overhead bridge crane (used in foundry, power house, steel industry, etc)

Elevators • • • • •

Group of fixed path handling equipment Bucket Elevator (BE) is one of them BE –used to convey material vertically BE are use to handle free flowing loads For example: – Grain storage – Food processing – Chemical plants

2 Types of Transporting Devices

• Wheel barrows • Hand and power trucks • Industrial narrow railways (used in mining and metal working industries before the development of rubber tire equipment)

• Tractors and trailers • Pipe lines and Pumps √ • Aerial tram ways (horizontal transportation

system where load carrying vehicle is supported from the top, by means of a cable –like Aerial Ropeways)

Pipe line and pumps in Material Handling • Pipe lines and pumps are used for transporting horizontal as well as vertical directions • Oil • Water • Gas • Concrete pumps in construction industry

3 Devices which lift and transport • Slides and Chutes (commonly used in railway, air line terminal, and department store for handling packages and baggages)

• Hoists with trolleys running on overhead rails • Fork lift truck √ (appropriate for process layout) • Crane trucks √

(appropriate for process layout)

• Conveyors √ (for line layout) • Spiral rollers • cranes

4 Industrial Robots • A robot is a reprogrammable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks • Robots are like human workers • Robot application: -to pick up hot steel ingots -handling radioactive rods in nuclear power plants -spot welding and arc welding

5 Automated Guided Vehicle systems (AVGS) • Battery-powered, automatically steered vehicles designed to follow defined pathways. • Capable of automatically loading and unloading unit loads • Usually interfaced with other automated systems to achieve full benefits of integrated automation. • Examples: driverless trains, pallet trucks, unit load carriers

Relation between plant layout and MH • Close relation between plant layout and MH • MH methods influence the layout and factory building • MH is to be considered as an integral part of plant layout to design low cost handling system • Good MH is resulted based on the arrangement of production equipment, location of departments, logical sequence of operations, location of stores, tools • MH system/equipment can be selected only after the appropriate floor plan • Plant layout considers the points for material receiving and shipping of products • Careful arrangement of work centers and storage areas • Consider horizontal or vertical material transportation

Process layout and MH system • Need of flexibility-flexibility of path, and flexibility of size, weight and shape of load • This requirement is better fulfilled by the MH equipment such as mobile trucks, tractor trains, cranes, and forklift trucks, etc. • Loading and unloading time is very important for efficient MH system • Quick pick up systems have developed around skids and pallets • Material is loaded directly on skid or pallet by worker as S/he completes his operation on the part • Heavy parts/loads are handled by overhead cranes • How much MH equipment is needed? Difficult question because of random variations on demand for transporting capacity in process layouts.

Line layout and MH • Nature of line layout requires direct means of transportation between operations • Arrange the material flow so that each operator places the unit down in such a position that it can be picked up by the succeeding worker • Where possible gravity chutes can be used • Chutes are common in railway and air line terminal for handling baggages. • Conveyers to lift all types of parts are available • These conveyers require a considerable amount of special design to fit them into an effective overall design of a line layout (Reference: M. Mahajan (2002). Industrial engineering and production management)

Task for self study • Review the literatures on material handling equipment. Understand the basic physical construction and application of major material handling equipment used in manufacturing and construction sector. Participate actively in class room discussion and demonstrate your knowledge and understanding ability on material handling equipment. TOP | HOME