DETERMINATION OF INVENTORY PERIODIC REVIEW POLICY (R, s, S) USING POWER APPROXIMATION METHOD FOR MINIMIZE TOTAL INVENTORY COST IN PT. OPQ

Author(s):  
Ratna Wia ◽  
Rio Aurachman ◽  
Saskia Puspa Kenaka

PT. OPQ is a company engaged in the automotive manufacturing industry. The company produces bolts for the safety area, it is related to the lower body of the four-wheeled vehicle. PT. OPQ was established in 2014 and today has already been the supplier for several major automotive companies in Indonesia. The demand of PT OPQ that must be fulfilled is increasing as the amount of consumer is increasing too. Due to the high demand, so the raw material stockout occurs. This make the company's service level is below the standard. This study involved 48 sku of material raw materials that have normal distributed demand. Inventory policy applied in this research is periodic review (R, s, S) with the aim to minimize total cost of inventory and improve service level of company. The result of this research was found to decrease total inventory cost by 15% with the value of existing inventory cost Rp1.100.879.479,- to Rp 936.061.349,- . In addition, service level at PT. OPQ has increased with the value of existing conditions 85% to 99%.

2019 ◽  
Vol 3 (01) ◽  
pp. 47-52
Author(s):  
Ratnawia ◽  
Rio Aurachman ◽  
Saskia Puspa Kenaka

OPQ is a company engaged in the automotive manufacturing industry. The company produces bolts for the safety area, it is related to the lower body of the four-wheeled vehicle. PT. OPQ was established in 2014 and today has already been the supplier for several major automotive companies in Indonesia. The demand of PT OPQ that must be fulfilled is increasing as the amount of consumer is increasing too. Due to the high demand, so the raw material stockout occurs. This make the company's service level is below the standard.   This study involved 48 sku of material raw materials that have normal distributed demand. Inventory policy applied in this research is periodic review (R, s, S) with the aim to minimize total cost of inventory and improve service level of company.   The result of this research was found to decrease total inventory cost by 15% with the value of existing inventory cost Rp1.100.879.479,- to Rp 936.061.349,- . In addition, service level at PT. OPQ has increased with the value of existing conditions 85% to 99%.   Keywords—Raw Material, Periodic Review, Probabilistic, Service Level, Stock out


2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Puspandam Katias ◽  
Achmad Affandi

The increasing competition in the manufacturing industry caused increasing inconsumer demand of the quality and quantity of a good product. Therefore, manufacturing companies must have reliable services, policies and product qualities to satisfy its customers. So it needs to be supported by efficient production system and inventory system. To able to create an efficient production system then need a good raw material inventory planning. This research aims to compere how efficiently in planning raw materials inventory between Wagner-Within Algorithm with the actual concept that applied to PT X, Sidoarjo. The methodology of this research is qualitative descriptive research. The findings this research is engaged in packaging (woven bag and jumbo bag) with main raw materials such as plastic ore and supporting material in inner, thread, additive, and pigment. Based on the result of the analysis is known that the actual concept of the company gives the total inventory cost IDR 3.151.000.000 with the frequency of ordering 12 times while WagnerWithin Algorithm method provides a more efficient total inventory cost of Rp. 2.685.821.101 with8 times the frequency of ordering and can savings of 14.8% of total raw material inventory cost.


2017 ◽  
Vol 1 (2) ◽  
Author(s):  
putri suwarni ◽  

Abstract The results of initial observation at PT. Japfa Comfeed Indonesia obtained data that the company always buys raw materials and auxiliary materials in large quantities and does not pay any attention to reorder in order not to run out of stock of raw materials and additives. To describe and analyze the optimal inventory and minimize the total cost of raw material inventory and additive then conducted qualitative research extrapolation (descriptive) by using EOQ method. The object of this research is the amount of raw material inventory and additional material at PT. Japfa Comfeed Indonesia. The raw material in this research is Brand Pollard, Stone Flour. Additional materials include Termin and Palm Oil. The results obtained with the optimal buyer Brand Pollard in 2016 amounted to 1,185,906 kg and in 2016 amounted to 1,215,745 kg. The purchase of Stone Flour 2016 is 677,847 kg and in 2016 it is 711,395 kg. The purchase of Palm Oil and Terminal in 2015 amounted to 282,281 liters and 212,776.8 liters respectively. Brand Pollard reorder point in 2015 and 2016 amounted to 139.968 kg Purchase of Stone Flour in 2015 and 2016 amounted to 38,166 kg. Palm Oil and terminal purchases in 2015 and 2016 amounted to 19,200 liters and 16,440 liters respectively. Financially, the company can make inventory cost savings up to Rp 88,043,000.00. The conclusion of this research is the determination of the amount of raw material inventory and additional material with EOQ method which more efficient compared with company policy. The optimal inventory and total inventory cost savings can be obtained by EOQ method so that the company can obtain maximum profit. Suggestion related to this research is company must evaluate applied policy and apply EOQ method in management of raw material inventory and additional material to get maximum profit. Keywords : Raw Material Inventory, Supplementary Material Inventory, Total Quantity Economica


2017 ◽  
Vol 4 (1) ◽  
pp. 8
Author(s):  
Adhi Putra Mahardika ◽  
Muhammad Nashir Ardiansyah ◽  
Efrata Denny S. Yunus

Spare parts is one of the production support components which plays an important role for the survival<br />of gas production in the gas processing facility owned by SKN JOB Pertamina Talisman Jambi Merang. The<br />high inventory level increased the high inventory cost for the industry which get the benefit from the efficiency<br />of processes and resources. This research involved consumable spare parts for Solar Turbine engine as much<br />as 25 SKUs with demand character patterned lumpy demand and Poisson distribution. The implementation<br />of policies using Periodic Review (R, s, S) with Power Approximation approach in the inventory system<br />capable to generate a lower total cost inventory by pressing the backorder volume, the booking volume and the<br />inventory levels in a balanced manner. Calculation of Periodic Review (R, s, S) with Power Approximation<br />approach resulted inventory parameter which was able to press the total cost of inventory at 8.54% lower and<br />increase the service level by 1.11%.


2019 ◽  
Vol 1 (2) ◽  
pp. 415-423
Author(s):  
Elia Rahayu R ◽  
Nor Norisanti ◽  
Acep Samsudin

The purpose of this study is to control the supply of raw materials using the Economic Order Quantity (EOQ) method in Tahu Nugraha Jaya Sukabumi UKM. The data analysis method used is quantitative descriptive to describe and describe the data to be examined and then processed using EOQ. This study uses the EOQ method to determine the total inventory cost. The data needed in this study are the number of purchases of raw materials, the amount of use of raw materials, storage costs, and ordering costs. The results of this study indicate that by applying the EOQ method can further optimize the supply of raw materials by minimizing raw materials with increased inventory. With the application of the Economic Order Quantity (EOQ) method it shows more efficient than conventional methods of the company. Conclusions, seen from the difference in the TIC of the two methods, the more efficient method is the Economic Order Quantity (EOQ) method that is equal to 244,392.94 while the calculation used by the company is 374,325. so that it can be obtained that there is a difference between the Company TIC and the EIC method TIC. Keywords: Raw Material Inventory, Production Process


Author(s):  
S. Nallusamy ◽  
R. Balaji ◽  
S. Sundar

A global market inventory is one of the largest and most significant resources of a manufacturing business. ABC analysis is one of the methods used extensively in manufacturing industries for inventory classification. The familiar ABC inventory classification approach categorizes inventory items as A, B and C classes according to their annual consumption value. To direct and control the inventory items more proficiently the inventories managers regularly classify and group all the inventory items. The objective of this paper is to create a periodic review policy based on the ABC classification in order to control the raw materials more efficiently. Based on the data collected through original equipment manufacturer, the necessary analysis was carried out. From the observed results, it was found that the developed periodic review policy improved the inventory turnover ratio from 3.15 to 2.13 by optimizing the inventory level for one year.


2020 ◽  
Vol 2 (2) ◽  
pp. 340
Author(s):  
Rizkyani Pratama ◽  
Yulius H Saptomo ◽  
Dirarini Sudarwadi

Controlling and determining of inventory is an important thing in order to produce efficiently and able to make smooth sales. The purpose of this research is to know an analysis of controlling raw material inventoriesin the manufacture of brick by using Economic Order Quantity (EOQ) method to increase efficiency of the total inventory costin Stan Kayu Sinar Sowi. The raw material of brick is rough sand and cements. Type of case study research through a qualitative approach by means of interviews, observation and documentation. Case study on a wood booth business in Manokwari, West Papua. The results of the study that the purchase of raw materials made by the company is considered less efficient, because company policies tend to cause expenditure to be greater in the amount of Rp.606,620,250 for 12 months (1 period), while using the Economic Order Quantity (EOQ) method will issue a fee of Rp.550,712,500 for the same period. Using the Economic Order Quantity (EOQ) method, the order quantity is higher and the order frequency will be lower, resulting in order cost savings and increasing the total inventory cost efficiency.


2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Paduloh Paduloh

This study aims to analyze the optimal usage volume of iron raw plates required by PT. Misitama for the period of 2017. PT. Misitama is a company engaged in the field of tank manufacturing industry for the needs of manufacturing and mining industries. The study analyzed the total cost of Iron Iron raw material supply which must be used by PT. Misitama during 2017, analyzing reorder point, safety stock and raw material inventory control using EOQ method. The data used is the data of September 2017 - October 2017. The data used is secondary data derived from corporate data. The results show that the amount of raw material purchases during 2017 if using the EOQ method becomes lower. The optimal purchase of raw materials to be done by the company in 2017 is 14.8 m2 with the frequency of ordering to be done as much as 8 times. The quantity of safety stock (Safety Stock) that must be available in warehouse of 7 m2 and reorder point (reorder point) EOQ that is when the warehouse inventory is only 8.88 m2. Total inventory cost for production process issued by PT. Misitama by using EOQ method becomes smaller than the total cost of previous inventory.


2021 ◽  
Vol 328 ◽  
pp. 05002
Author(s):  
Dira Ernawati ◽  
Sinta Dewi ◽  
Ni Ketut Sari ◽  
Kurniawan Budianto

Inventory is one of the current assets that can be classified as company assets. But in reality, inventory often turns into an operational problem that can affect the company's overall performance. This problem occurs due to the incorrect determination of the amount of inventory. Both excess and shortage of inventory can lead to cost overruns. This study applies the Wagner Whitin Algorithm and the Silver-Meal method in the lot-sizing process and the ABC (Always Better Control) method in determining the classification of raw materials at PT. X. Using the ABC method, it is known that the ADC-12 Ingot item has a very significant effect to inventory. Inventory optimization using the Wagner Whitin Algorithm and the Silver-Meal method resulted in the optimal frequency of ordering ADC-12 Ingots is 9 times and the total inventory cost is 994,098,000 IDR as well as inventory cost savings of around 18,403,180 IDR or 1.8% of the cost of existing inventory.


2021 ◽  
Vol 9 (12) ◽  
pp. 650-660
Author(s):  
*Bolarinwa, Mojisola A. ◽  
Fajebe, Fisayo E.

Asides inventory cost, which is being used as the only inventory performance measure at the University of Ibadan bakery, a number of other criteria, such as inventory cost, service level, inventory turnover and delivery lead time which influence the performance of an inventory system have surfaced over the years. Hence, there is the need to examine all these criteria-objectives altogether. Therefore, this research was centred towards optimising the inventory system of University of Ibadan bakery, putting multiple criteria into consideration. Data on 17 raw materials: their costs, suppliers, usage rate, lead time, storage space and available capital were collected by means of interviews, past records and observations. The weighted goal program algorithm was adopted to find the best compromise between fulfilling the four objectives by minimising the sum of the deviation from the target values of the goals. Subsequently, Lingo 17.0 and Tora 1.0 optimisation software packages were used to solve and compare the model generated, while putting into consideration storage space constraint and budgeted capital. The developed model from the goal programming algorithm exhibited four goals (combined into one objective function). Same solutions were obtained from Lingo 17.0 and Tora 1.0. While Lingo 17.0 gave a  uniform service level of 100% , a  turnover ratio greater than 1(>1) for all the materials at a negligible increase (of  < 0.0001%) in total inventory cost of the raw materials and available lead time duration of zero days (< 24 hours) for each material, Tora 1.0  gave a  uniform service level of 100% , a  turnover ratio greater than 1 (> 1) for all the materials at a negligible increase (of  < 0.0001%) in total inventory cost of the raw materials and available lead time duration of zero days (< 24 hours) for each material. Implementation of the developed model will eliminate unnecessary waiting time between production, thereby ensuring effective and efficient utilisation of raw materials in production which will lead to reduced cost of holding inventory, elimination of unnecessary overall cost and wastages, and also improvement of the productivity and profit on the long run.


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