Inventory management


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Inventory management

  1. 1. BySherief Ashraf Ahmed Reda
  2. 2. "Inventory" to many small business owners is one of the more visible and tangible aspects of doing business. Raw materials, goods in process and finished goods all represent various forms of inventory. Each type represents money tied up until the inventory leaves the company as purchased products.Likewise, merchandise stocks in a retail store contribute to profits only when their sale puts money into the cash register.
  3. 3. In a literal sense, inventory refers to stocks of anything necessary to do business. These stocks represent a large portion of the business investment and must be well managed in order to maximize profits. In fact, many small businesses cannot absorb the types of losses arising from poor inventory management. Unless inventories are controlled, they are unreliable, inefficient and costly.
  4. 4. Inventory management is primarily about specifying the size and placement of stocked goods. Inventory management is required at different locations within a facility or within multiple locations of a supply network to protect the regular and planned course of production against the random disturbance of running out of materials or goods.Inventory management involves a retailer seeking to acquire and maintain a proper merchandise assortment while ordering, shipping, handling, and related costs are kept in check.
  5. 5. The scope of inventory management also concerns the fine lines between replenishment lead time, carrying costs of inventory, asset management, inventory forecasting, inventory valuation, inventory visibility, future inventory price forecasting, physical inventory, available physical space for inventory, quality management, replenishment, returns and defective goods and demand forecasting. Balancing these competing requirements leads to optimal inventory levels, which is an on-going process as the business needs shift and react to the wider environment.
  6. 6.  Buffer/safety stock Cycle stock (Used in batch processes, it is the available inventory, excluding buffer stock) De-coupling (Buffer stock that is held by both the supplier and the user) Anticipation stock (Building up extra stock for periods of increased demand - e.g. ice cream for summer) Pipeline stock (Goods still in transit or in the process of distribution - have left the factory but not arrived at the customer yet)
  7. 7. The reasons for keeping stock:There are three basic reasons for keeping an inventory:• Time - The time lags present in the supply chain, from supplier to user at every stage, requires that you maintain certain amounts of inventory to use in this "lead time."• Uncertainty - Inventories are maintained as buffers to meet uncertainties in demand, supply and movements of goods.• Economies of scale - Ideal condition of "one unit at a time at a place where a user needs it, when he needs it" principle tends to incur lots of costs in terms of logistics. So bulk buying, movement and storing brings in economies of scale, thus inventory.All these stock reasons can apply to any owner or product stage.
  8. 8. Buffer stock is held in individual workstations against the possibility that the upstream workstation may be a little delayed in long setup or change over time. This stock is then used while that changeover is happening. This stock can be eliminated by tools like SMED(Single –Minute Exchange of Die).These classifications apply along the whole Supply chain, not just within a facility or plant.
  9. 9. Where these stocks contain the same or similar items, it is often the work practice to hold all these stocks mixed together before or after the sub-process to which they relate. This reduces costs. Because they are mixed up together there is no visual reminder to operators of the adjacent sub-processes or line management of the stock, which is due to a particular cause and should be a particular individuals responsibility with inevitable consequences. Some plants have centralized stock holding across sub- processes, which makes the situation even more acute.
  10. 10.  Stock Keeping Unit (SKU) is a unique combination of all the components that are assembled into the purchasable item. Therefore, any change in the packaging or product is a new SKU. This level of detailed specification assists in managing inventory. Stock out means running out of the inventory of an SKU. New old stock (sometimes abbreviated NOS) is a term used in business to refer to merchandise being offered for sale that was manufactured long ago but that has never been used. Such merchandise may not be produced anymore, and the new old stock may represent the only market source of a particular item at the present time.
  11. 11.  Raw materials - materials and components scheduled for use in making a product. Work in process, WIP - materials and components that have begun their transformation to finished goods. Finished goods - goods ready for sale to customers. Goods for resale - returned goods that are salable.
  12. 12.  Purpose:-Inventory proportionality is the goal of demand-driven inventory management. The primary optimal outcome is to have the same number of days (or hours, etc.) worth of inventory on hand across all products so that the time of run out of all products would be simultaneous. In such a case, there is no "excess inventory," that is, inventory that would be left over of another product when the first product runs out. Excess inventory is sub-optimal because the money spent to obtain it could have been utilized better elsewhere, i.e. to the product that just ran out.
  13. 13. The secondary goal of inventory proportionality is inventory minimization. By integrating accurate demand forecasting with inventory management, replenishment inventories can be scheduled to arrive just in time to replenish the product destined to run out first, while at the same time balancing out the inventory supply of all products to make their inventories more proportional, and thereby closer to achieving the primary goal. Accurate demand forecasting also allows the desired inventory proportions to be dynamic by determining expected sales out into the future; this allows for inventory to be in proportion to expected short-term sales or consumption rather than to past averages, a much more accurate and optimal outcome.Integrating demand forecasting into inventory management in this way also allows for the prediction of the "can fit" point when inventory storage is limited on a per-product basis.
  14. 14.  Applications:-The technique of inventory proportionality is most appropriate for inventories that remain unseen by the consumer. As opposed to "keep full" systems where a retail consumer would like to see full shelves of the product they are buying so as not to think they are buying something old, unwanted or stale; and differentiated from the "trigger point" systems where product is reordered when it hits a certain level; inventory proportionality is used effectively by just-in- time manufacturing processes and retail applications where the product is hidden from view.
  15. 15. One early example of inventory proportionality used in a retail application in the United States is for motor fuel. Motor fuel (e.g. gasoline) is generally stored in underground storage tanks. The motorists do not know whether they are buying gasoline off the top or bottom of the tank, nor need they care. Additionally, these storage tanks have a maximum capacity and cannot be overfilled. Finally, the product is expensive.
  16. 16. Inventory proportionality is used to balance the inventories of the different grades of motor fuel, each stored in dedicated tanks, in proportion to the sales of each grade. Excess inventory is not seen or valued by the consumer, so it is simply cash sunk (literally) into the ground. Inventory proportionality minimizes the amount of excess inventory carried in underground storage tanks. This application for motor fuel was first developed and implemented by Petrolsoft Corporation in 1990 for Chevron Products Company. Most major oil companies use such systems today.
  17. 17.  Roots:-The use of inventory proportionality in the United States is thought to have been inspired by Japanese just-in-time parts inventory management made famous by Toyota Motors in the 1980s.
  18. 18. It seems that around 1880. there was a change in manufacturing practice from companies with relatively homogeneous lines of products to vertically integrated companies with unprecedented diversity in processes and products. Those companies (especially in metalworking) attempted to achieve success through economies of scope - the gains of jointly producing two or more products in one facility. The managers now needed information on the effect of product-mix decisions on overall profits and therefore needed accurate product-cost information. A variety of attempts to achieve this were unsuccessful due to the huge overhead of the information processing of the time. However, the burgeoning need for financial reporting after 1900 created unavoidable pressure for financial accounting of stock and the management need to cost manage products became overshadowed. In particular, it was the need for audited accounts that sealed the fate of managerial cost accounting. The dominance of financial reporting accounting over management accounting remains to this day with few exceptions, and the financial reporting definitions of cost have distorted effective management cost accounting since that time. This is particularly true of inventory.
  19. 19. Hence, high-level financial inventory has these two basic formulas, which relate to the accounting period: Cost of Beginning Inventory at the start of the period + inventory purchases within the period + cost of production within the period = cost of goods available Cost of goods available − cost of ending inventory at the end of the period = cost of goods sold
  20. 20. Successful inventory management involves balancing the costs of inventory with the benefits of inventory. Many small business owners fail to appreciate fully the true costs of carrying inventory, which include not only direct costs of storage, insurance and taxes, but also the cost of money tied up in inventory. This fine line between keeping too much inventory and not enough is not the managers only concern. Others include: Maintaining a wide assortment of stock -- but not spreading the rapidly moving ones too thin; Increasing inventory turnover -- but not sacrificing the service level; Keeping stock low -- but not sacrificing service or performance. Obtaining lower prices by making volume purchases -- but not ending up with slow-moving inventory; and Having an adequate inventory on hand -- but not getting caught with obsolete items.
  21. 21. The degree of success in addressing these concerns is easier to gauge for some than for others. For example, computing the inventory turnover ratio is a simple measure of managerial performance. This value gives a rough guideline by which managers can set goals and evaluate performance, but it must be realized that the turnover rate varies with the function of inventory, the type of business and how the ratio is calculated (whether on sales or cost of goods sold). Average inventory turnover ratios for individual industries can be obtained from trade associations.
  22. 22. To maintain an in-stock position of wanted items and to dispose of unwanted items, it is necessary to establish adequate controls over inventory on order and inventory in stock. There are several proven methods for inventory control. They are listed below, from simplest to most complex. ! Visual control enables the manager to examine the inventory visually to determine if additional inventory is required. In very small businesses where this method is used, records may not be needed at all or only for slow moving or expensive items. ! Tickler control enables the manager to physically count a small portion of the inventory each day so that each segment of the inventory is counted every so many days on a regular basis. ! Click sheet control enables the manager to record the item as it is used on a sheet of paper. Such information is then used for reorder purposes. ! Stub control (used by retailers) enables the manager to retain a portion of the price ticket when the item is sold. The manager can then use the stub to record the item that was sold.
  23. 23. As a business grows, it may find a need for a more sophisticated and technical form of inventory control. Today, the use of computer systems to control inventory is far more feasible for small business than ever before, both through the widespread existence of computer service organizations and the decreasing cost of small-sized computers. Often the justification for such a computer-based system is enhanced by the fact that company accounting and billing procedures can also be handled on the computer. ! Point-of-sale terminals relay information on each item used or sold. The manager receives information printouts at regular intervals for review and action. ! Off-line point-of-sale terminals relay information directly to the suppliers computer who uses the information to ship additional items automatically to the buyer/inventory manager.
  24. 24. The final method for inventory control is done by an outside agency. A manufacturers representative visits the large retailer on a scheduled basis, takes the stock count and writes the reorder. Unwanted merchandise is removed from stock and returned to the manufacturer through a predetermined, authorized procedure.
  25. 25. A principal goal for many of the methods described above is to determine the minimum possible annual cost of ordering and stocking each item. Two major control values are used: 1-Order Quantity: The size and the frequency of orders. 2-Reorder Point: The minimum stock level where additional quantities are ordered.
  26. 26. In recent years, two approaches have had a major impact on inventory management: Material Requirements Planning (MRP) and Just-In-Time (JIT). Their application is primarily within manufacturing but suppliers might find new requirements placed on them and sometimes buyers of manufactured items will experience a difference in delivery.
  27. 27. Material requirements planning is basically an information system in which sales are converted directly into loads on the facility by sub-unit and time period. Materials are scheduled more closely, thereby reducing inventories, and delivery times become shorter and more predictable. Its primary use is with products composed of many components. MRP systems are practical for smaller firms. The computer system is only one part of the total project which is usually long-term, taking one to three years to develop.Just-in-time inventory management is an approach which works to eliminate inventories rather than optimize them. The inventory of raw materials and work-in-process falls to that needed in a single day. This is accomplished by reducing set-up times and lead times so that small lots may be ordered. Suppliers may have to make several deliveries a day or move close to the user plants to support this plan.
  28. 28. At time of delivery Verify count -- Make sure you are receiving as many cartons as are listed on the delivery receipt. Carefully examine each carton for visible damage - - If damage is visible, note it on the delivery receipt and have the driver sign your copy. After delivery, immediately open all cartons and inspect for merchandise damage.
  29. 29. When damage is discovered Retain damaged items -- All damaged materials must be held at the point received. Call carrier to report damage and request inspection. Confirm call in writing--This is not mandatory but it is one way to protect yourself.
  30. 30. Carrier inspection of damaged items Have all damaged items in the receiving area -- Make certain the damaged items have not moved from the receiving area prior to inspection by carrier. After carrier/inspector prepares damage report, carefully read before signing.After inspection Keep damaged materials -- Damaged materials should not be used or disposed of without permission by the carrier. Do not return damaged items without written authorization from shipper/supplier.