Inventory management techniques are extremely critical for business operations because their success and cost decrease of the firm’s use require improved supply chain performance and information to the workers (Lambert, 2008). These procedures are basic and information in them is profoundly desirable in this way, managers and obtainment staff need to be able to apply the procedures for the advantage of the organization (Fellows and Rottger, 2005).
Wild (2002) suggests, proper warehousing of stock so that when products items are requested, they are kept at the warehouse for the least time possible minimizing holding cost of stock. Consequently, other operational costs may increase inventory management costs. The way an organization is able to maintain its costs at low levels the way better it is for the year end profits (Palevich, (2012), Wisner, Tan and Leong (2011)). Organizations purchase and sell their stock; there continuously arises balance at the end of the year which have to be be carried over to the next year. Once an organization realizes this, it can create online stock management tool to monitor its stock information by breaking it down into groups by
connecting the categories with its clients. Since organizations works differently in numerous fields, the stock can be classifies by either seasons or financial year conclusion of your most critical clients thus, request forecasting got to be employed to have an proficient supply chain (Poiger, 2010).
2.6.1 Re-Order Level
As organization endeavor to achieve effectiveness, they should be able to understand their ReOrder Levels (ROL) which empowers them know when to order and when not to order. This may be accomplished through the use of quantitative strategies which require proper inventory management (Apte, 2010). Re-Order level is critical for Aref Contractor Company to attain optimal efficiency and be successful leading to high supply chain performance and client satisfaction, at that point they need to have two reorder levels one that’s normal whereas the other is an emergency one in case of disaster (Beamon and Kotleba, 2006).
2.6.2 Economic Order Quantity
Bachetti, Plebani, Saccani and Syntetos (2010) contends that inventory management got to be organized in a consistent way so that the organization can be able to know when to order and how much to order. This will only be accomplished through the Economic Order Amount (EOQ) computation. Economic order amount enables organization to plan their stock replenishment on a timely basis such as month to month, quarterly, half yearly or yearly basis. By so doing, it empowers firms to have minimal storage costs or zero within their warehouses since stock is coming in and going out instantly. In this way, this tends towards the just in time concept of supply chain management received by Toyota motor Organization in Japan which helps in having zero holding costs, (Schonberger, 2008). In this way, as
organizations try to progress on the stock management, the Economic Order Quantity (EOQ) and Re-order Point (ROP) are critical tools that organizations can use to guarantee that stock supply does not hit a stock out as explained by Gonzalez and Gonzalez (2010). Over time, organizations have been keeping up their stock in a haphazard way which has required a change within the way firms conduct their business. Stock outs have been experienced adversely leading to client dissatisfaction hence; firms are changing their approach to be able to stay important by employing Economic Order Quantity (EOQ) and Re-order Point (ROP) for client satisfaction.
The derivation of the basic EOQ model (Quantity of economic order) is quite simple in a situation
Figure 2 EQO Equivalents
To determine the economic order quantity given the fixed demand assumption, we can
evaluate the following model:
D = Total annual demand in unit
Q = Economic order quantity in unit
D/Q = Number of orders placed and received during the year
Q/2 = Average inventory
Co = Cost of placing an order
Cc = Carrying cost per unit of inventory during the year
Total inventory cost is defined as the whole of ordering cost and carrying cost. To define total inventory cost in terms of the controllable variable order amount (Q), we must express both types of cost in terms of amount. Total ordering cost can be gotten by multiplying the number of orders D/Q by the cost of placing an order (Co), consequently:
Annual ordering cost = D/Q Co
So also, annual carrying cost can be found by multiplying the carrying cost per unit of inventory (Cc) by the average number of units in stock (Q/2). This expression for average inventory accept a steady rate of demand all through the year.
Annual carrying cost = D/2 Cc
Combining the two components, we get total inventory cost for the period:
TC = D/Q Co + Q/2 Cc
Review that this variable can be controlled by management to yield the least cost for inventory amid a particular time period. From Fig. 2.5.2 we know that optimum solution is that quantity (Q*) that can therefore be gotten by setting the equation for ordering cost equals to the equation for carrying cost and solving for Q: thus:
Annual carrying cost = annual carrying cost
Cc Q/2 = DCo/Q
Cc Q2 = 2DCo
Q2 = 2DCo/Cc
The ideal solution is also obtained by separating the total cost function to get an equation that expresses the rate of change in total cost with respect to changes in quantity. When the first derivative of the total cost function is set equal to zero, the economic order quantity is obtained by solving for Q.
The operation is as follows in three steps:
1. Take the first derivatives of total cost function:
TC = D/Q Co + Q/2 CC
d(TC)/dQ = -DCo/Q2 + Cc/2
2. Set the first derivative equal to zero, and solve for Q:
-DCo/Q2 + Cc/2 = 0
3. Test to determine the solution is a minimum.
d2(TC)/dQ2 = 2DCo/Q3 0
Given the assumption of fixed demand, the equation can be utilized in finding the economic order quantity (Q*), which is equal to the square root of 2 times demand (D) times ordering cost (Co) divided by carrying cost (Cc) For example; assume the following example:
D = 3000 units per annum
Co = N30
CC = N2 per unit per year
To obtain the Economic order quantity, we evaluate the basic equation using the values for demand, ordering cost and carrying cost.
Q = ?(2 × 300 × 30 ÷ 2)
Q = 300 units
The optimum order quantity is 300 units. Observe that a total of ten order will be placed.
D = 3000 = 10
Q* = 300
For a total cost due to ordering of 300. Average inventory will be 150 units.
Q*/2 = 300/2 = 150
an inventory carrying cost will equal N300. Therefore, total inventory cost will be equal to N600.
Just-in-time (JIT) is a positive performance to the company . Inventory should be managed by using JIM to reduce loses and customer`s satisfaction. Invontory management in organizations that kept too much stock in their warehouse were an wasteful supply chain, whereas those that kept very few stock in their warehouse were exceptionally productive (Lai and Cheng, 2009). Thus, it was found out that keeping direct stock is nice and it empowers an organization work minimal costs of holding costs as well as keep setup cost at bare minimum, increase unwanted lead time and produce goods as per clients order. Eventually, this empowers an organization accomplish total quality control (TQC) as efficient and successful supply chain management are employed inside a firm’s value chain (Datta, 2007).
Figure 3 Source: manufacturingtomorrow.com
2.6.4 Activity Based Costing Analysis
Fellows and Rottger (2005) agree that having stock in your store has an advantage for the organization since clients will be satisfied immediately . With stock in your warehouse, an organization has the advantage of timely delivery . Thus, Aref Contractor Company got to guarantee that they have adequate stock for their operations . One way they can accomplish this is thorough the “Pareto Analysis” also known as Activity Based Costing (ABC) analysis. ABC analysis is where stocks are classified into three categories to be specific : A – stock items that are of high value and material to the organization but low volume such as building and