A STUDY OF CURRENT SITUATION OF PURCHASING AND INVENTORY CONTROL TO DEVELOP A PREVENTATIVE PURCHASING MODEL

Abstract

The research has objectives that are to present the theories and guidelines for efficient order planning and inventory management. To develop a preventative purchasing model that must be taken into account the shelf life. And to reduce the inventory. The sample of this study from January-December 2019, including a 12 months period for forecasting the trend of demand for raw materials in 2020. The tools used are Fishbone theory or officially known as Cause and Effect Diagram. The Cause and Effect Diagram is a map showing the relationship between a Problem and all possible causes that may cause a Possible Cause. Analyze inventory classification With the method of ABC Analysis to the time series forecasting technique and analysis, measurement, accuracy of forecasting Is a comparison of the forecasted values and the values from the actual data to see how much difference which is to find the error in forecasting or the difference between actual demand and forecast if the forecast is effective, the error will be low. And must not be biased By means of measuring the accuracy of the percent absolute error (Mean Absolute Percentage Error or MAPE)

               The results showed that when the theory of Cause and Effect Diagram is analyzed. The root of the order forecasting problem is that there is "No Method" to obtain a form of forecasting. And the theory of classification and significance, ABC Analysis, is used to obtain a forecast model for ordering and controlling warehouses with low discrepancies. From time series forecasting techniques. It was a result that the proposed forecasting method was more accurate than the current forecasting method. With the error 26.47% less than the current method. And there was a decrease in inventory holdings each month.