22. Inventory management Flashcards
Define stock/inventory
Materials and goods required to allow for the production and supply of products to the customer
What are the 3 elements of stock/inventory?
- Raw materials: purchased from outside supplier, held in stock so that firm can use it at any time to meet increase demand
- Work in progress: main form of stocks held. Value of stocks depend on the length of time needed to complete + method of production
- Finished product: displayed to potential customers and held to cope with sudden increases in demand
Why do stocks need to be managed?
- Insufficient stocks to meet unforeseen changes in demand
- Stock wastage might occur due to mishandling or incorrect storage conditions
- Very high stock levels raise stock holding costs
- Poor management leads to late deliveries, low discounts
What are the stock-holding costs?
- Opportunity costs: working capital tied up in stock could be put to another use
- Storage costs: stocks have to be held in secure warehouses. Often require special conditions => special equipment. Staff will needed to guard and transport stocks. Insurance of stocks
- Risk of wastage and obsolescence: if stocks are not used/ sold as rapidly as expected => risks of goods deteriorating or becoming outdated
Costs of not holding enough stocks
- Lost of sales: unable to supply customers from stock => lost orders
- Idle production resources: if stocks of raw materials and components run out, production will have to stop => labour and equipment are idle
- Small order quantities: low stock levels => only ordering goods and supplies in small quantities => lose out bulk discounts and transport costs could be higher
Define economic order quantity
The optimum or least cost quantity of stock to re-order taking into account delivery costs and stock holding costs
Explanation of economic order quantity
The purchasing manager must ensure that supplies of the right quality are delivered at the right time at sufficient quantities. High large orders => gain economies of scale and reduce re-order costs but increases stock holding costs
Define buffer stocks
The minimum stocks that should be held to ensure that production could still take place should a delay in delivery occur or should production rates increase. The less reliable suppliers are, the greater the buffer stock level might have to be
Define maximum stock level
The highest capacity of inventory the factory can hold. Limited by space or financial costs of holding higher stock levels
Define re-order quantity
The number of units ordered each time. Influenced by the economic order quantity
Define lead time
The normal time taken between ordering new stocks and their delivery. The longer the lead time, the higher the re-order stock level will be
Define re-order stock level
Level of stocks that will trigger a new order to be sent to supplier
Define just-in-time
This stock control method aims to avoid holding stocks by requiring supplies to arrive just as they are needed in production and completed products are produced to order
Requirements for JIT principles to be applied
- Relationships with the suppliers have to be excellent
- Production staff must be multi-skilled and flexible
- Equipment and machinery must be flexible/ latest IT equipment
- Accurate demand forecasts
- Quality must be everyone’s priority
Advantages of JIT
- Capital invested in inventory is reduced and the opportunity costs of stock holding is reduced
- Costs of storage and stock holding are reduced. Space can be used for a more productive purpose
- Much less chance of stock becoming outdated or obsolescent or of wastage and damage
- Quicker response time to changes in consumer demand or tastes
