Ch 7 and 8 Handout WHM - Lecture note. Itis a lecture note that describse about how procurement is done PDF

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Lecture note. Itis a lecture note that describse about how procurement is done in governmental institutions....

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Chapter VII Storage and Materials Handling Equipment Management

7.1 Types of Storage Equipment Storage Equipment refers to one type of materials handling equipment used for holding or buffering materials over a period of time. Some storage equipment may include the transport of materials (e.g., the S/R machines of an Automatic Storage/Retrieval System (AS/RS), or storage carousels). If materials are block stacked directly on the floor, then no storage equipment is required. The most common reason for storing a product allows the other elements of production to operate more efficiently on a per-unit basis because the fixed costs associated with utilizing the element can be spread over more products; e.g., storing up to a truckload of product in a facility reduces the per-unit costs of shipping; and buffering or storage of WIP enables batch production which reduces the per-unit setup costs. Other potential reasons for storage include: time bridging—allows product to be available when it is needed (e.g., storing spare machine parts at the facility); processing—for some products (e.g., wine), storage can be considered as a processing operation because the product undergoes a required change during storage; and securing—e.g., nuclear waste storage. The major types of storage equipment are: Block staking (no equipment), selective pallet rack, drive-through rack, drive-in rack, flow-through rack, sliding rack, cantilever rack, stacking frame, shelves/bins/drawers, Automatic Storage/Retrieval System (AS/RS), and mezzanine. Popularly used storage equipment are presented and discussed as follows: 1. Block Stacking (No Equipment) Block stacking in which boxes or pallets are stacked directly upon each other. Bulk storage using block stacking can result in the minimum cost of storage since cube utilization is high and no storage medium is required, but material accessibility is low since only the top of the front stack is accessible and loads at bottom of a stack must not require support. Storage racks are used when support and/or material accessibility is required. In all block stacking the primary considerations are:  Safety and stability of stack: it depends upon stacks being built so that each component (made up of a block or goods which can be considered as and entity) stands securely on its own, whatever happens to the component next to it. Each of these units of storage should use boxes as if they were bricks or that they bind themselves into a solid wall. Obviously, it is pointless spending time and trouble in making stacks stable if workers are allowed to remove stores at random, thus Page | 1

destroying stability. It is vital, therefore, that boxes within any component are removed on picking, layer by layer.

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In the course of issuing stores from block stacks, periodic storage maintenance is necessary if space is to be used economically. In this, it is important that good liaison between the Purchasing Department and the warehouse exits so that permanent reduction in stock holdings can be differentiated from normal usage run-down, locations being re-planned on the basis of real maximum likely holdings. Ease of Access: it must be planned when the stacks are building and, as has already been pointed out, this depends upon the nature of used. The other three considerations are matters of proper instruction and discipline. It is a matter of the amount of space devoted to aisles relative to the stock volume, i.e., access inversely to concentration. It must be planned with the equipment which is to operate in that area of the storehouse in mind. Once the must always be available,. If a particular block of racking is designed for use with side-loader instead. They are likely to be quite useless. The final result will be that an area designed to be operated using mechanical means will, in fact, have to be worked manually, at fearful risk. For this reason, there is something to be said for standardizing on certain types of mechanical handling to devices. Stock turnover: is difficult to arrange in block stacking, without the moving of large number of stores each time issue picking takes place or, alternatively, wasting a great deal of space. If one box or pallet frontage can be sacrificed in each row bearing the date of star and finish of binning and the current row for picking clearly indicated. Such a system gives an approximation to the first-in- first-out rule which is near enough for most purposes. Where pallets are used, the additional movement involved by not having such a system but keeping a note of the dates of receipt of pallet loads only is usually acceptable because of the speed with which these equipment’s can operate.

2. Selective Pallet Rack Most popular type of storage rack Pallets are supported between load-supporting beams Special attachments and decking can be used to make the racks capable of supporting other types of unit loads besides pallets (e.g., coils, drums, skids) Selective racks can be used for the following types of storage: Standard—single-deep storage using a counterbalanced lift truck Narrow-Aisle—storage using a narrow-aisle lift truck Deep-Reach—greater than single-deep storage (typically double-deep storage) Page | 2

3. Drive-Through Rack Loads are supported by rails attached to the upright beams Lift trucks are driven between the uprights beams Requires similar-width loads Open at both ends, allowing access from both ends (FIFO)

4. Drive-In Rack Same as drive-through rack, except closed at one end, allowing entry from only one end (LIFO)

5. Flow-Through Rack/ Live Racking Loads are supported on an incline to enable gravity-based movement of the loads within the rack (via, e.g., a gravity roller conveyor) Loaded at the higher end and unload at the lower end (FIFO)

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6. Cantilever Rack Loads are supported by cantilever "arms" Used to store long loads (e.g., bar stock, pipes, lumber) Similar to pallet racks, except the front upright beams and the front supporting beams are eliminated

7. Stacking Frame Interlocking units that enable stacking of a load so that crushing does not occur Can be disassembled and stored compactly when not in used Pallet frames can be used to enable multilevel block stacking Note: Variety of Racks are used as the picking face for items, which are too big or heavy

for shelves or bin or drawers accommodation or for reserve stocks for replenishing bins. 8. Shelves/Bins/Drawers

Binning is usually used for the primary”picking face” in a storehouse, i.e., it is the area which holds most of the stock items required for normal issue and from which most issues are made. There is a great variety of bins to choose from, including some which are mounted on rails so as to reduce aisle space to the minimum. There are two schools of thought in the use of bins; one holds that this type of storage is the most valuable and that as many items as possible should be put into it, refilling being done on a regular basis, i.e. daily for a supermarket. The other states that manpower and therefore movement is the most expensive commodity and that that task of replenishment should be made as easy as possible by arranging or the bin to hold rather more than the contents of a complete a package. This has the advantage that the package can be brought

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to the bin and subsequently disposed of. Both points of view are valid, the latter undoubtedly dissolving a considerable amount of work. Rules for binning of materials 1. Items must be binned by groups or classes. In other words, materials of the same group must be binned in continuation and not scattered about. 2. Materials must be properly labeled showing class, code and description for identification 3. To prevent deterioration, issues must be made on the principle of First-in-First–out (FIFO). Materials must therefore binned in such a manner as to facilitate this. It can be achieved by piling packages in two lots and issuing first lot first or by issuing from one end of the same pile and starting new piles in the vacant area. 4. As far as possible binning should also facilitate counting of materials at any time. 5. Fragile items like glass containers should not be binned along with metal articles 6. Items frequently required must be as near to the counter as possible to have easy access 7. Bulky but light items must be on the top shelves 8. The maximum utilization of floor space and overhead space should be made. 9. As far as possible production components must be stored and issued in unit loads to reduce handling. 9. Automatic Storage/Retrieval Systems (AS/RS) Consists of an integrated computer-controlled system that combines the storage medium, transport mechanism, and controls with various levels of automation for fast and accurate random storage of products and materials. Storage/retrieval (S/R) machine in an AS/RS operates in narrow aisle, serving rack slots on both sides of aisle; can travel in horizontal (along the aisle) and vertical (up and down a rack) directions at same time Advantages: fewer material handlers, better material control (including security), and more efficient use of storage space Disadvantages: high capital and maintenance costs, and difficult to modify

Example of AS/RS is Man-On-Board AS/RS Used for in-aisle picking; operator picks from shelves, bins, or drawers within the storage structure Manual or automatic control S/R machine is similar to an order picker or turret truck and can sometimes operate as an industrial truck when outside an aisle, except the S/R is guided along a rail when operating in an aisle

10. Mezzanine Page | 5

Inexpensive means of providing additional storage or office space Makes use of clear space over activities not requiring much headroom (e.g., restrooms, block storage, etc.). At least 14 ft. (4.20 meters) of clear space is needed for a mezzanine

7.2 Materials Handling What is it? A vital part of a warehouse, terminal, or plant is the movement of product in the facility. The formal definition of material handling is “the art and science of moving, packaging, and storing of substances in any form.” In general, whenever material is moved in a manufacturing, distribution/warehouse, or office environment, materials handling occurs. Also in the vast sea, air and land transportation network, materials handling occurs in the various aspects of preparing merchandise such as: for shipment, in order filling, and in moving materials in and out of carriers, be they private, government or commercial. A properly installed materials handling system can reduce costs and labor, increase safety, increase productivity, reduce waste, increase capacity, and improve service. Unfortunately, managers and workers sometimes cannot see materials handling problems or solve them. Depending on the industry, materials handling can account for 30 to 70 percent of the cost of manufacturing, so inefficiencies should be eliminated. Such inefficiencies may include: cluttered aisles, too much manual labor, lack of standardization, high loss and damage; excess scrap, flow inefficiencies, too much walking, idle cube storage, lack of gravity flow movement, excess amounts of employees etc. Eliminating these problems improves product movement and decreases material handling costs. The Objectives of Materials Handling Commerce and industry have always thrived on competition. Unfortunately, although the consumer profits from keen competition among members of the business community, some manufacturing, or distribution, or retail merchants disappear from the business scene because they become sub marginal producers or give way to a number of overwhelming inefficiencies. One of the most prevalent inefficiencies is that of poor materials handling practice. Current periodical literature supplies many examples of good materials handling practice, and new equipment is being invented and produced in relatively large numbers in many parts of the world. If it were just a question of reading the literature and buying new equipment, the world would have very little need for Materials Handling Engineer/Manager. But, it is in putting together all the elements of the system that the Materials Handling Engineer/Manager makes his/her largest contribution to the profit picture of any enterprise.

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As competition increases in an industry, or from country to country, it is the relative efficiency of the materials handling system that, in the final analysis, helps achieve the objective of the least total cost of handling and give the competitive edge to an organization. In manufacturing, machine tool suppliers sell the same high speeds and feeds to the compnay's competitor that they sell to the buying company. In warehousing, these competitors can use the same powered industrial trucks or the same high-rise, highdensity storage racks or stacker-crane retrieval machine that you do. Thus, the company has to stay competitive, therefore, by improving its Materials Handling System (MHS), all other factors being equal. So, after eliminating mechanical equipment and mechanization from the equation, there remain the Materials Handling System (MHS). It is by the systems approach, therefore, that the following materials handling objectives could possibly be achieved. 1. Improve production operations Production effectiveness can be increased by having “The right quantity of material, at the right place, at the right time.” Thus, the elements make up material handling include the movement of product into, through, and out of warehouses. Efficient movements inside a facility helps control costs and improve customer service. Time is the second element. Parts and raw materials must be available when needed at production stations, loading docks and terminals. Having the product in the facility but not in the right place at the right time causes managers to have nightmares. The third element is quantity. Goods must move in the right quantity between the production stations as well as to the customer. It is by eliminating or minimizing machine or operator time that many cost savings may be made, especially since an orderly flow of work through a plant increases the morale and productivity of the workforce. By systematizing this flow, in a manner to be the maximum output or through-put may be readily established. 2. Improve indirect to direct labor handling ratios There is an upward trend in most industry segments that reflects the growing labor force required to service and maintain increasingly complex equipment, for example, numerical controlled machine tools. There is another upward trend in the size of the labor force required to perform materials handling functions within the plant. One function of the systematic analysis of materials handling problems is to minimize unnecessary labor and make the enterprise more profitable so that the job security of the total work force is enhanced as the company’s position is improved relative to a competitor’s position 3. Reduce damage due to materials handling In-transit movements, either from suppliers to plant, from plant to plant, or in-plant, have a tendency to increase the level of damage that occurs to the product being handled. Suffice it to say that of the cornerstones of good materials handling is a solid and wellconceived packaging program. This packaging program should encompass the type of containers, packaging method, identification of, etc. Page | 7

Since scrap and re-work can be costly, one should make every attempt to prevent such loses by the proper training of materials handlers and by getting good data on the costs of damage due to materials handling. When one knows the scope of the problem and the type of damage that has occurred, the person can take steps to minimize or eliminate it. 4. Maximize space utilization Space is one of the materials handling system. Thus, the system should effectively use the available cubic storage space in the warehouse, terminal, or plant. Factory and warehouse space becomes more costly each year. It is even more costly when viewed from the standpoint of the dislocations and lost time that occur when a move is made or when plant expansion takes place. In layout planning, therefore, the Materials Handling Engineer/Manager should have a direct input into new projects, or for that matter, any project that affects the handling of parts in one way or another. 5. Reduce the accident rate and severity of injury The fifth objective has to do with the worker him/herself. The most important element of any materials handling project is the safety of the worker. Without due regard for this factor the systems concept becomes invalid and worthless. The real professional in this business makes safety his/her number one concern, always. Expert materials handling practice requires each job involving the movement of materials to become safer every time it is performed, rather than the reverse. In short! Good practice should remove all factors that contribute to carelessness and an increase in the accident rate. In United States, for instance, the new OSHA (i.e. the Occupational Safety and Health Administration of the U.S. Department of Labor) requires the safety of materials handling practices in any organizations. Principles of Materials Handling Applying the “ten principles of material handling” can overcome many material handling problems. These principles offer commonsense approaches to moving products more efficiently and effectively. Before applying these principles, it is important to review the material handling checklist such as: _______ _______ _______ _______ _______ _______ _______ _______ _______

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Is the material handling equipment more than 10 years old? Are equipment breakdowns the result of poor preventive maintenance? Are there excessive employee accidents due to manual handling equipment? Are materials weighting more than 23 kilos handled manually? Does material become congested at any point? Are single piece being handled where unit load could be used? Is handling equipment being overloaded? Are indirect labor costs too high? Is power equipment used on jobs that could be handled by gravity?

This checklist forces the Material Handling Manager to think through the material handling system and its attributes. Having answered the questions, the Manager should then analyze the material handling principles in an attempt to overcome any inefficiencies uncovered in the checklist analysis. These principles are: all materials handling should be the result of a deliberate plan where the needs, performance objectives and functional specification of the proposed methods are completely defined at the outset. 2. Standardization Principle: material handling methods equipment, controls and software should be standardized within the limits of achieving overall performance objectives and without sacrificing needed flexibility, modularity, and throughput. 3. Work Principle: material handling work should be minimized without sacrificing productivity of the level of service required of the operation. 4. Ergonomic Principle: human capabilities and limitations must be recognize and respected in the design of material handling tasks and equipment to ensure safe and effective operations. 5. Unit Load Principle: unit loads shall be appropriately sized and configured in a way that achieves the material flow and inventory objectives at each stage in the supply chain. 6. Space Utilization Principle: effective and efficient use must be made of all available space. 7. System Principle: materials movement and storage activities should be fully integrated to form a coordinated, operational system, that spans receiving, inspection, storage, production, assembly, packaging, unitizing, order selection, shipping, transportation, and the handling of returns. 8. Automation Principle: material handling operations should be mechanized and/or automated where feasible to improve operational efficiency, increase responsiveness improve consistency and predictability, decrease operating costs, and eliminate repetitive or po...