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Inventory Control by Analyzing the Economic Order
Quantity (EOQ) Method to Reduce Low & Off
Production
Luqman Arif 1), Hasmznnd Zusi 2 , Erry Rimawan 3) Magister Management, Mercu Buana University
Abstract:- The company in an effort to increase revenue
in the condition of world oil prices down now is to
prevent the rate of decline in production due to low & off
production. Based on existing low & off data from 2013 to
2017 shows a fairly high upward trend, from 10% to
15%. While the maximum target of the company for the
low & off rate is 8%.
From the background of these problems, it is seen
that the cause of the high low & off production is because
the supply material to replace damaged equipment is not
available (stock out). This research aims to provide an
alternative solution to the problem of inventory about
optimum stock and saving inventory costs and can offer
policies for inventory systems that are implemented in the
company so as to reduce low & off production.
The results of the study using the EOQ method,
ABC analysis and calculation of inventory material
forecast obtained EOQ prices, order frequency, safety
stock, ROP, maximum inventory and total inventory cost
(TIC). From the results of the calculation of Total
Inventory Cost (TIC) carried out by the company with
the existing method and the calculation of total inventory
cost (TIC) using the EOQ model, there is a difference in
numbers, which means saving inventory costs by the
company Rp. 776,443,130 or 190% of the EOQ model on
in 2016 and Rp 810,884,069 or 212% of the EOQ model
in 2017, as well as Rp 810,884,069 or 212% of the EOQ
model in 2018
From the research it was concluded that the
calculation of the EOQ method by considering the
assumptions in the study can be used as one of the
methods for planning optimal material inventory control
so that there is no problem of lack of stock material which
will have an impact on high & low production wells. The
company is looking at reviewing existing forecasts and
seeing trends in material usage, so that the optimum stock
of material used is obtained.
Keywords:- ABC Analysis, Forecast, EOQ, Order
Frequency, Safety Stock, ROP, Maximum Inventory, Total
Inventory Cost (TIC).
I. INTRODUCTION
The company in an effort to increase revenue in the
condition of world oil prices down now is to prevent the rate
of decline in production due to low & off production. Based
on existing low & off data from 2013 to 2017 shows a fairly
high upward trend, from 10% to 15%. While the maximum
target of the company for the low & off rate is 8%.
From the background of these problems, it is seen that
the cause of the high low & off production is because the
supply material to replace damaged equipment is not
available (stock out). This research aims to provide an
alternative solution to the problem of inventory about
optimum stock and saving inventory costs and can offer
policies for inventory systems that are implemented in the
company so as to reduce low & off production.
II. BASIC THEORY
A. Wells and Low & off Production Production Systems In general, the stages of production of wells in stages or
methods of production are divided into two, namely:
Natural flow stage (Natural Flowing).
Production pipe strings (production strings) used in
producing wells in natural blast are:
Tubing (production pipe)
Tubing packers with casing
Artificial lift stages, among others, include common
methods:
Gas lifts
Suction pump (Sucker Rod Pump)
Submergible Pump
Low & off production is a parameter used to observe
the production performance of wells to the potential of wells
in normal conditions. The definition of operational low & off
terms includes:
Low is a lack of production (against potential) in the
condition of wells that are still in production.
Off is a lack of production (according to potential) in the condition of a well die / downtime stop production.
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Low & off is the average potential per month reduced by
the average monthly production.
B. ABC Analysis
Bandaru, Aslam, Ng and Deb (2015) ABC clarification
or often referred to as ABC analysis is a clarification of a
group of materials in a declining arrangement based on the
cost of material use per time period (the price per material
unit multiplied by the volume of use of that material over a
certain period ) The commonly used time period is one year.
With the ABC method, inventory is grouped into three
major groups, where this benchmark is distinguished by the
level of capital absorption of an item, 3 groups, namely:
Group A.
This group is items that absorb capital in a large
percentage. The types of goods in this group amount to 15-
25% of all types of goods available, and absorb capital of 70
- 80% of all capital embedded in the inventory.
Group B.
The group of items that absorb capital is 15-20% of the
total capital and the amount of goods itself is 30-40% of the
total number of goods available.
Group C.
The group of goods that absorb capital is 5 - 10% of the
total capital, and the number of goods covers 40% of all
existing goods.
C. Forecasting
Forecasting is an estimate of the level of demand
expected for a product or several products in a certain period
of time in the future. Therefore, forecasting is basically an
estimate, but using certain methods of forecasting can be more than just one estimate. Three uses of forecasting
include:
Determine what is needed for plant expansion.
Determine advanced planning for existing products to be
done with existing facilities.
Determine short-term scheduling of existing products to
be worked on based on existing equipment.
Judging from the nature of the predictions that have
been compiled, the forecasting can be divided into two types,
namely:
Qualitative or technological forecasting, namely forecasting based on past qualitative data. The existing
forecasting results depend on the person who compiled it,
because the forecasting is largely determined by intuition
thinking, judgment (opinion) and the knowledge and
experience of its constituents.
Quantitative forecasting, namely forecasting based on
quantitative data in the past. The forecasting results are
made depending on the method used in the forecasting. A
good method is a method that provides possible values of
differences or deviations
Quantitative forecasting methods are divided into two
main types of forecasting models, namely:
Periodic series models (time series), namely forecasting
methods based on the use of pattern analysis of
relationships between variables that will be estimated
with time variables, which is a time series.
Causal model, namely: Forecasting method based on the
use of pattern analysis of the relationship between other
variables that influence it, which is not time called the
correlation or causal method.
Forecasting techniques in outline can be grouped into 2,
namely:
Time Series Method (Time Series)
Broadly speaking, the time series method can be
grouped into:
Averaging Method
The methods included, among others:
Simple Average
Single Moving Average Double Moving Average
Smoothing method (smoothing)
Used in conditions where the weight of data in one
period is different from the data in the previous period and
forms an Exponential function commonly called Exponential
smoothing.
The methods included, among others:
Single Exponential Smoothing
Double Exponential Smoothing one parameter from Browns
Double Exponential Smoothing Two Parameters from
Holt
Linear Regression
D. Inventory
According to Assauri (2008), the notion of inventory in
this case is as an asset which includes goods belonging to the
company with the intention to sell in a normal business
period, inventory of goods which are still under construction
/ production process, or raw material inventory waiting for its use in a production process.
The causes of inventory are as follows (Kusuma, 2009):
Mechanism of fulfillment upon request.
The desire to reduce uncertainty
The desire to speculate is aimed at gaining big profits
from future price increases.
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While according to Rangkuti (2007: 15) the inventory
function can be divided into 3:
Decoupling function is inventory that allows companies
to meet customer demand without depending on suppliers.
Economic Lot Size Function
Anticipation Function, If the company faces fluctuations
in demand that can be predicted and predicted based on
past experience or data, namely seasonal demand.
According to Indrajit and Djokoparnoto (2005: 47),
inventory demand systems are divided into 3, namely:
Independent request system is the type of demand for a
free item, meaning that it does not depend on the time or number of requests for other goods. Such requests are
usually uniform and relatively more orderly. In an
independent request system like this, the calculation
models for the number of re-orders include:
The booking system is fixed, in this system for every time
the order ordered is always fixed. The most popular
model is the EOQ model (Economic Order Quantity).
Pile production system, this system is oriented to the
production of goods in certain piles. A fairly popular
model is the EPQ formula (Economic Production
Quantity), ROT (Runout Time Method), AROT
(Aggregate Runout Time Method).
Fixed periodic system, this system is used to calculate or
review inventory re-ordering based on a fixed time
schedule. There are several models developed in this
system, including EOI (Economic Order Interval).
Minimum-maximum system, this system adheres to the
understanding that the minimum amount of inventory
should be carried out to ensure the continuity of the
company's operations, but also needs to be set to
maximize the amount of goods not controlled in an
uncontrolled manner.
Dependent demand systems are types of goods whose
time or amount are not free to stand alone, but depend on
the time or number of requests for other goods. The most
famous ordering model in this system is MRP (Material
Requirement Planning).
Demand system with its own characteristics, in this
system the demand for goods despite the nature of
certainty, but the amount, time and frequency of use has
its own pattern, which changes in a certain period of time,
sometimes - sometimes regularly and sometimes -
irregularly. Nenes, G. (2010) usage patterns that are repeated every year (seasonal) or every few years
(cyclical), and there are patterns of usage that are
completely irregular.
E. Method of Economic Order Quantity (EOQ)
EOQ (Econimc Order Quantity) is the number of orders
that can minimize total inventory costs, optimal purchases.
To find out how much total material is still to be purchased in
each purchase to cover the needs for one period. To be able
to achieve these goals, the company must fulfill several
factors regarding the supply of raw materials. The factors are: Estimated usage, management must be able to make
estimates of raw materials to be used in the production
process in a period.
Price of material, The price of raw materials is the basis
for compiling the calculation of how much company
funds must be prepared for investment in terms of the
supply of raw materials.
Inventory costs, According to Rangkuti (2017: 16) costs
related to inventory include:
Inventory Cost (Holding Cost or Carrying Cost).
Ordering costs or purchase costs (ordering costs or procurement costs).
Manufacturing costs or set-up costs.
Costs of running out or lack of material (shortage costs)
a. Actual usage
b. Waiting time, lead time is the time needed (which occurs)
between when ordering raw materials and the arrival of
the raw material itself.
c. Material purchasing mode.
d. Safety stock, is an additional inventory that is held to
protect or maintain the possibility of a stock out. Safety
inventory in Slamet (2007: 72) is the amount of minimum material inventory that must be owned by the company to
maintain the possibility of delays in the arrival of raw
materials, so there is no stagnation. The amount of safety
stock is determined by the formula:
Safety stock (SS) = (SF x SD) ……………. (1)
Where:
SS = Safety Inventory.
SF = 1.28 (calculation of 90% SL).
D = average demand for goods for a certain period. σD = demand deviation standard (Calculated by formula).
e. Reorder (reorder point) is the time or certain time the
company must order raw materials again, so that the
arrival of the order is right with the end of the raw
material purchased, especially with the EOQ method.
Determination or determination of the reorder point must
pay attention to the factor-factor as follows:
Use of materials for a period of time to get ingredients.
The amount of safety stock.
The reorder point formulation in Slamet (2007: 72), is
as follows:
ROP = (LT.AU) + SS ……………………… (2)
Where :
ROP = the point of reorder.
LT = lead time.
AU = average usage for a certain period
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SS = safety stock / safety stock
f. Calculating Maximum Inventory
Maximum inventory can be calculated using the
following formula:
MI = SS + EOQ ……………………………. (3)
Where :
MI = Maximum inventory.
SS = Safety Stock
g. To get the optimal amount of material purchases every
time a booking with a minimum cost according to Slamet (2007: 70) can be determined by the Economic Order
Quantity (EOQ) and Reorder Point (ROP). To determine
the number of orders that are economical according to the
EOQ method are:
Order frequency according to Deanta's exposure in
Rifqi (2012: 40) can be described as follows:
Where:
EOQ = number of orders that are economical / economic
order quantity D = request / use of goods for a certain period (unit)
S = booking fee for each message
H = storage cost per period per unit
h. TIC (Total Inventory Cost), In calculating total inventory
costs, it aims to prove that with the optimal amount of raw
material purchases, calculated using the EOQ method will
be achieved with a minimum total inventory cost. Total
Inventory Cost (TIC) can be formulated as follows:
Where:
TIC = Total Inventory Cost.
S = Message Fee. H = Save Cost.
Di = Request.
Ci = Price per unit
Qi = EOQ
III. METHODOLOGY
A. Types of research
This research method is descriptive method.
Descriptive research method because researchers not only
provide an overview of the phenomena that exist, but also
explain the relationship, and get the meaning and
implications of a problem you want to solve
B. Variable Measurement
Researchers use inventory control by using EOQ, where
quantities will be ordered, order frequency, safety stock,
ROP, maximum inventory, and TIC (Total Inventory Cost)
C. Population and Samples
The population is 72 items (material) production strings
namely tubing, sucker rod and artificial lift (down hole
pump) which consists of rod pump and ESP while the sample
is historical material demand data, material price data,
material ordering data lead time, holding cost component,
and ordering costs from 2016 - 2017.
D. Method of collecting data
To collect data used method:
Interview or interview method, namely: by conducting direct interviews with competent company employees,
namely with warehouse assistant manager and staff with
minimum 3 years work experience.
Documentation, namely the method of collecting data
through existing documentation, namely from the system
data (SAP), is expected to obtain usage data components
(spare parts), for the waiting time (lead time), number of
orders, ordering costs, storage costs obtained from
interviews.
IV. HASIL DAN PEMBAHASAN
A. Material Inventory Grouping
From the data of the quantity (quantity) of inventory
and the price per unit of the existing inventory in the
company using ABC analysis, the classification of inventory
material is obtained into three groups of inventory materials
as in table 1.
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inventory
group investment value (Rp)
% investment towards
cumulative investment
% inventory against
cumulation %cumulative
A 26,156,494,437 62% 8% 8%
B 11,447,171,417 27% 15% 24%
C 4,412,172,840 11% 76% 100%
Total 42,015,838,693
Table 1:- Classification of ABC analysis needs
The inventory group A material which will be the basis
of the research calculation of forecasting (forecast) material usage for 2016 - 2017 and one year in the future namely
2018. Material group A as listed in table 2.
Table 2:- Material supplies for group A to be analyzed
B. Results of Optimum Forecast Analysis of the Company
In this study, the forecasting method used for material
use is the Moving Average (with variations 1,2,3,4 and 5
months), Exponential Smoothing, and Exponential
Smoothing With Trend with data for 24 months (2016 -
2017). The results are as follows;
Table 3:- Optimum Forecast Method Test
Based on the results of processing the above material
use with Ms. Excel 2016, the best forecasting method is the Moving Average variation of 3 Months, with MAD 474;
MSE 944,483; and MAPE 1.61.
Then, for forecasting the use of each material in 2016 to
2018 it will be calculated using the Moving Average method
which has the smallest error value based on the existing
calculations in accordance with table 3
C. Material Use in 2016-2017 and Permit for Use in 2018
Material usage during 2016 and 2017 can be seen from the table below.
Table 4:- 2016 Material Use Tables.
Table 5:- 2017 Material Use Tables
From the two tables of usage above and by using the
Moving Average forecasting method by calculating using
Ms. Excel 2016 will get the usage forecast for each material
for the next 12 months in 2018 which can be seen from the
graphs below.
Material Deskripsi Material
A ROD,SUCKER,MLD,3EA STEALTH-XL,D,3/4 X25'
B ROD,SUCKER,MLD,3EA STEALTH-XL,D,7/8 X25'
C SUCKER ROD, SIZE 3/4 IN, 25 FT, D
D SUCKER ROD, SIZE 7/8 IN, 25 FT, D
E TUBING, 2.7/8 IN, J-55, 6.5 PPF, EUE, R2
F BALL & SEAT 1.3/4IN FLAT CARBIDE SEAT
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Graph 1:- Prognosis of Use of Material A
From Graph 1, the usage of material A (ROD, MLD,
3EA STEALTH-XL, D, 3/4 X25 ') has decreased in the end
of 2016, there is no use even in 2017 but it starts to be used at
the end of 2017 which is quite large so cause the trend to rise
and then stabilize in the range of +/- 600 EA for use in 2018. This condition is caused by the absence of stock or use due to
production wells that are shut in (dead) a little and there are
changes in design in the production strings to reduce the low
number & off.
Graph 2:- Prognosis of Use of Material B
For the use of material B (ROD, MLD, 3EA
STEALTH-XL, D, 7/8 X25 ') in 2016 until 2017 there is no
use in 2017 but it starts to be used at the end of 2017 which is
quite large causing a trend to rise and then stable in the range of +/- 600 EA for use in 2018 as shown in graph 2. This
condition is caused by the absence of stock or use due to
production wells that are shut in (dead) a little and there are
changes in design in the production strings to reduce the low
number & off.
Graph 3:- Prognosis of Use of Material C
From Graph 3, the usage of material C (SUCKER
ROD, SIZE 3/4 IN, 25 FT, D) has decreased in the end of
2016, there is no use even in 2017 but starting to use at the
end of 2017 is only small enough to cause no the trend rose
and was stable in the range of +/- 4 EA for use in 2018. This
condition was caused by the use of production wells which were shut in (dead) a little and there was a change in design
in the production strings to reduce the low & off rate.
Graph 4:- Prognosis of Use of Material D
From Graph 4, the usage of material D (SUCKER
ROD, SIZE 7/8 IN, 25 FT, D) has decreased in the end of
2016 from around 400 - 300 EA to 50 EA and there is no use
in 2017 causing no trend there was no increase in usage even
in 2018. This condition was caused by the use of production
wells which were shut in (dead) a little and there was a
change in design in the production strings to reduce the low
& off rate.
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Graph 5:- Prognosis of Using Material E
From Graph 5, the usage of E material (TUBING, 2.7 /
8 IN, J-55, 6.5 PPF, EUE, R2) decreased in the end of 2016, the initial usage ranged from 400-600 EA to 200 EA but
began to increase usage at the end 2017 is large enough to
cause a trend to rise and then stabilize in the range of +/- 800
EA for use in 2018. This condition is caused by the absence
of material stock and usage due to production wells that are
high shut-off so that the numbers are low & off in 2016 it
was quite high and there was a change in design in the
production strings to reduce the number of low & off in the
next year.
Graph 6 shows that the use of F material (BALL & SEAT 1.3 / 4IN FLAT CARBIDE SEAT) has decreased in
the end of 2016 with initial usage ranging from 20-30 EA to
5 EA but has begun to increase usage at 30 EA in early 2017
and has decreased to 10 EA at the end of 2017, causing a
stable trend in the range of +/- 8 EA for use in 2018. This
condition is caused by the absence of material stock and
usage due to production wells that are shut in (dead) high so
that the low & off rate in 2016 was quite high and there was a
change in design in the production strings to reduce the
number of low & off in the next year.
Graph 6:- Prognosis of Use of Material F
From the results of forecasting (forecast) with the
moving average method with a 3-month series seen from graphs 1 - 6 for all materials experienced an increase in
forecasting usage in 2018. There is only material C
(SUCKER ROD, SIZE 3/4 IN, 25 FT, D), material D
(SUCKER ROD, SIZE 7/8 IN, 25 FT, D), and material F
(BALL & SEAT 1.3 / 4IN FLAT CARBIDE SEAT) which
experienced a downward trend and even for material D in
2017 and 2018 not there is use of existing tables and graphs.
D. EOQ Material Calculation and Order Frequency
For the calculation of EOQ (economic order quantity)
and order frequency of each material in 2016-2017, it will
use data from ordering costs and holding costs for each material as in table 6 & table -7.
The price of EOQ is obtained by Formula as follows:
Order Frequency Prices are obtained with the following
formula:
With the same method and formula, the results of the
calculation of EOQ and ordering frequency for 2016-2018
each material can be displayed and seen in tables-8, 9 and
table-10.
E. Calculation of Material Safety Stock Inventory for 2016-
2018
The price of Safety stock is obtained with the Safety
stock equation = (safety factor x standard deviation)
Data Material A is known as follows:
Average Usage = 113
Standard deviation = 173
Service level = 90% (data used as an assumption)
Service Factor = 1.28 (calculation of 90% SL)
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From the data above, the Safety stock of material A can
be known by the existing formula, namely: Safety Stock = safety factor x standard deviation
= 1.28 x 173
= 222 EA
So our 90% service level needs a safety stock of =
(serfive factor x std dev), which is equal to 222 with an
average usage of 113 EA. With the same method and
formula, the results of the calculation of the safety stock
usage for 2016-2017 each - each material can be displayed
and seen in table-11 and table-12. While for 2018 can be seen
in table-13.
F. Reorder Point (ROP)
Calculations for determining the reorder point (ROP)
can be calculated using the following equation:
ROP = Safety Stock + (Lead Time x needs per day)
From the existing data the lead time of each material is
assumed to be the same, that is equal to 60 days.
Data Material A is known as follows:
Safety Stock = 222 Lead Time = 60
Daily Use = 1.355 / 365 (for 1 year)
From the data above, ROP material A can be known by the
existing formula, namely:
So the re-order price (ROP) of material A is equal to
445 EA, which means that a re-order will be made when material A has reached 445 EA in 2016.
With the same method and formula, the results of the
usage re-calculation (ROP) for 2016-2017 each material can
be displayed and seen in tables-14 and table-15. while for
2018 can be seen in table 16.
G. Maximum Inventory Calculation (Maximum Inventory)
The maximum inventory is needed by the company so
that the amount of material inventory in the Warehouse does
not exceed the investment budget or capital set so there is no waste on operational budget costs and capital costs. To find
out the maximum inventory size (maximum inventory), use
the formula in the equation as follows, namely:
Maximum Inventory = Safety Stock + EOQ
Data Material A is known as follows:
Safety Stock = 222
EOQ = 478
From the data above, maximum inventory material A
can be known by the existing formula, namely:
Maximum inventory = Safety Stock + EOQ
= 222 + 478
= 700 EA
So the maximum inventory price of material A is 700
EA, which means that there will be no re-order when material
A has reached 700 EA or the maximum inventory for
material A is 700 EA in 2016.
With the same method and formula, the results of
calculating the maximum inventory (maximum inventory) usage for 2016-2017 each - each material can be displayed
and seen in tables 17 and 18. While for 2018 can be seen in
table 19.
H. Calculation of Material Total Inventory Cost (TIC)
To obtain the minimum total cost of material inventory,
a comparison between the calculation of material inventory
costs and the EOQ method is needed with the calculations
made by the company so far. This is done to find out how
much the total cost of material inventory is saved at the
company.
Calculation of total inventory costs according to the
EOQ method will be calculated using the Total Inventory
Cost (TIC) formula, the equation used in calculating the
Total Inventory Cost (TIC) and in rupiah as follows:
Where the Message Fee (S), Material Usage (D),
Economict Order Quantity (EOQ), Savings Cost (H), and Price of unit (Ci).
Data Material A is known as follows:
Message Fee (S) = 15,000,000
Usage (D) = 1,355
EOQ = 478
Cost of Save (H) = 10%
Unit price (Ci) = 1,777,552
From the data above, the total inventory cost (TIC) of
material A can be known by the existing formula, namely:
With the same method and formula, the calculation of
the total inventory cost (TIC) used by the company using the
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EOQ method for the period 2016-2018, as shown in tables
23, table 24, and table 25.
From the table, the smallest total inventory cost (TIC)
in 2016 is material B because it has the lowest usage of Rp.
7,842,947. While in 2017 D material has the lowest total
inventory cost (TIC) of Rp. 6,415,608. For 2018, D material
has the lowest total inventory cost (TIC) and even zero
because there is no use.
I. Calculation of Total Inventory Cost (TIC) Existing
Methods 2016-2018
While the calculation of total inventory cost (TIC)
carried out by the company so far will be calculated using the average inventory available in the company using the
following formula:
TIC = {(Inventory average x H) + (S x F)}.
Data needed for calculations are average inventory,
save costs, message costs, number of months.
Data Material A is known as follows:
Average Inventory = 113
Cost of saving (H) = 177.755
Message Fee (S) = 15,000,000 Number of Months (F) = 12
From the data above, the total inventory cost (TIC) of
material A can be known by the existing formula, namely:
TIC = {(Inventory average x H) + (S x F)}
= {(113 x 177,755) + (15,000,000 x 12)}
= Rp. 200,071,502
With the same method and formula, the results of the
calculation of the total inventory cost (TIC) used by the
company with the existing method for the period 2016-2018, as shown in tables 26, table 27, and table 28.
The smallest total inventory cost (TIC) in 2016 is
material B because it has the lowest usage of Rp.
180,068,346. While in 2017 D material has the lowest total
inventory cost (TIC) of Rp. 180,000,000. For 2018, D
material has the smallest total inventory cost (TIC) of Rp.
180,000,000 because there is no use.
To compare the total inventory cost (TIC) of the EOQ
method with the total inventory cost (TIC) of the existing method material and the amount of savings generated during
the period 2016-2017, and 2018 can be seen in table-29,
table-30, and table- 31.
In tables-29, table-30, and table-31 show that in 2016
there is a difference in value between the total inventory cost
(TIC) from the calculation of the existing method with the
calculation of the EOQ method of Rp. 776,443,130 or 190%
greater than the TIC value calculated by the EOQ method.
Whereas in 2017 there is a difference in value between the
total inventory cost (TIC) from the calculation of the existing method and the calculation of the EOQ method of Rp.
810,884,069 or 212% greater than the TIC value calculated
by the EOQ method. While in 2018 there was a difference in
value between the total inventory cost (TIC) from the
calculation of the existing method and the calculation of the
EOQ method of Rp. 609,244,112 or 91% greater than the
TIC value calculated by the EOQ method.
From the explanation of the difference in TIC value
between the calculation of the Existing method and the EOQ
method it can be called the savings value obtained by the
company.
V. CONCLUSION
Calculation of the EOQ method by considering the
assumptions in the study can be used as one of the
methods for planning optimal material inventory control
so that there is no problem of lack of stock material which
will have an impact on high & low production wells.
The detailed calculation of the EOQ value, order
frequency, safety stock, ROP and maximum inventory
can be seen in tables 20, table 21, and table 22. From the results of the Total Inventory Cost (TIC)
calculated by the company with the existing method and
the calculation of the Total Inventory Cost TIC using the
EOQ model, there is a difference in numbers which
means that the company's inventory cost is IDR
776,443,130 or 190% of the EOQ model. in 2016 and Rp.
810,884,069 or 212% of the EOQ model in 2017, and Rp.
810,884,069 or 212% of the EOQ model in 2018. This
can be seen in tables 29, table-30, and table 31.
REFERENCES
[1]. Indroprasto, Suryani,Ema. 2012. “ Analisis Pengendalian
Persediaan Produk Dengan Metode EOQ menggunakan
Algoritma Genetika untuk mengefisienkan Biaya
Persediaan”. Jurnal Teknik ITS Vol 1.
[2]. Jaggi, Chandra K., and Mittal,Mandeep. 2011.
“Economic Order Quantity Model for Detoriarating
Items with Imperfect Quality.”, Journal Operation
Research Mathematical Sciences, Vol. 32. No. 2-107-
113.
[3]. Maimun, A.2008. “Perencanaan Obat Antibiotik
berdasarkan Kombinasi Metode Konsumsi dengan analisis ABC dan Reorder point terhadap nilai
Persediaan dan Turnover Ratio di Instalasi Farmasi RD
Darul Istiqomah Kaliwungu Kendal”. Tesis. Universitas
Diponegoro.
[4]. Manaf, A.M., Akib, M. and Kusmiyati, K.2016.
“Analisis Penilaian Persediaan Pada PT. Putra Wirawan
Gas Kendari”. Jurnal Akutansi.1(1).
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 437
[5]. Matsuyama, Keisuke. 2007. “The General EOQ Model
with Increasing Demand and Cost” . Journal of the Operation Research Society of Japan. Vol 44, No.2.
[6]. Yu lin, Tien. 2011. “An Economic order quantity model
with screening errors, returned cost, and shortages under
quantity discounts”. Journal of business management.
Vol 5(4), pp 1129-1135.
[7]. Mathew,Aju. 2013. “Demand Forecasting For Economic
Order Quanitity in Inventory Management”.
International Journal of Scientific and Research
Publications, Volume 3. Issue 10.1-6.
ATTACHMENT
Table 6:- Table of Material Usage, Prices Per EA, Booking
Fees and Storage Costs in 2016
Table 7:- Table of Material Usage, Prices per EA, Booking
Fees and Storage Costs in 2017
Table 8:- EOQ Calculation and Frequency of Orders in 2016
Table 9:- EOQ Calculation and Frequency of Ordering 2017
Table 10:- EOQ Calculation and Frequency of Bookings in
2018
Jumlah Harga/EA Total Harga Pesan Simpan
EA Rp Rp Rp Rp
ROD,SUCKER,
MLD,3EA
STEALTH-
1,355 1,777,552 2,408,582,348 15,000,000 177,755
ROD,SUCKER,
MLD,3EA
STEALTH-
10 2,050,394 20,503,940 15,000,000 205,039
SUCKER ROD,
SIZE 3/4 IN, 25
FT, D
1,293 1,290,000 1,667,970,000 15,000,000 129,000
SUCKER ROD,
SIZE 7/8 IN, 25
FT, D
1,861 1,372,001 2,553,293,861 15,000,000 137,200
TUBING, 2.7/8
IN, J-55, 6.5
PPF, EUE, R2
2,733 2,101,442 5,743,240,986 15,000,000 210,144
BALL & SEAT
1.3/4IN FLAT
CARBIDE SEAT
109 2,110,812 230,078,508 15,000,000 211,081
Biaya Pemakaian
2016
Item PartTahun
Jumlah Harga/EA Total Harga Pesan Simpan
EA Rp Rp Rp Rp
ROD,SUCKER,
MLD,3EA
STEALTH-
XL,D,3/4 X25'
1,615 1,777,552 2,870,746,480 15,000,000 177,755
ROD,SUCKER,
MLD,3EA
STEALTH-
XL,D,7/8 X25'
1,623 2,050,394 3,327,789,137 15,000,000 205,039
SUCKER ROD,
SIZE 3/4 IN, 25
FT, D
40 1,290,000 51,600,000 15,000,000 129,000
SUCKER ROD,
SIZE 7/8 IN, 25
FT, D
10 1,372,001 13,720,008 15,000,000 137,200
TUBING, 2.7/8
IN, J-55, 6.5
PPF, EUE, R2
3,376 2,101,442 7,094,466,757 15,000,000 210,144
BALL & SEAT
1.3/4IN FLAT
CARBIDE SEAT
95 2,110,812 200,527,140 15,000,000 211,081
Tahun Item Part
Pemakaian Biaya
2017
Tahun MaterialPemakaian
EAEOQ
Freq.
Pemesanan
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,355 478 2.83
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'10 38 0.26
SUCKER ROD, SIZE 3/4
IN, 25 FT, D1,293 548 2.36
SUCKER ROD, SIZE 7/8
IN, 25 FT, D1,861 638 2.92
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R22,733 625 4.38
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT109 124 0.88
2016
Tahun MaterialPemakaian
EAEOQ
Freq.
Pemesanan
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,615 522 3.09
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'1,623 487 3.33
SUCKER ROD, SIZE 3/4 IN,
25 FT, D40 96 0.41
SUCKER ROD, SIZE 7/8 IN,
25 FT, D10 47 0.21
TUBING, 2.7/8 IN, J-55, 6.5
PPF, EUE, R23,376 694 4.86
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT95 116 0.82
2017
Tahun MaterialPemakaian
EAEOQ
Freq.
Pemesanan
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'6,556 1,052 6.23
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'6,853 1,001 6.84
SUCKER ROD, SIZE 3/4 IN,
25 FT, D53 111 0.48
SUCKER ROD, SIZE 7/8 IN,
25 FT, D0 0 0.00
TUBING, 2.7/8 IN, J-55, 6.5
PPF, EUE, R29,478 1,163 8.15
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT75 103 0.73
2018
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 438
Table 11:- Calculation of Safety Stock Usage in 2016
Table 12:- Calculation of Safety Stock for Use in 2017
Table 13:- Calculation of the Use of Safety Stock in 2018
Table 14:- Calculation of Ordering Returns (ROP) for Use in
2016
A B C D E F TOTAL
JAN 0 0 367 168 123 0 658
FEB 0 4 89 18 314 0 425
MAR 0 0 160 256 189 3 608
APR 0 0 569 274 40 18 901
MAY 192 0 106 375 204 29 906
JUN 130 0 0 142 241 8 521
JUL 426 0 0 34 344 14 818
AUG 483 0 1 184 550 20 1,238
SEP 0 0 0 342 675 8 1,025
OCT 0 0 0 5 27 6 38
NOV 124 0 0 59 0 3 186
DEC 0 0 0 4 26 0 30
113 0 108 155 228 9 613
1,355 4 1,292 1,861 2,733 109 7,354
173 1 182 134 215 9 390
90% 90% 90% 90% 90% 90% 90%
1.28 1.28 1.28 1.28 1.28 1.28 1.28
222 1 233 171 275 12 499
SERVICE LEVEL
SERVICE FACTOR
SAFETY STOCK
TOTAL
PEMAKAIAN TYPE MATERIALTAHUN BULAN
2016
AVERAGE
STD DEV
A B C D E F TOTAL
JAN 0 0 0 0 121 31 152
FEB 0 0 0 0 29 5 34
MAR 0 0 0 0 310 11 321
APR 0 0 0 0 289 11 300
MAY 0 0 0 0 172 6 178
JUN 0 0 15 0 61 1 77
JUL 123 0 0 0 165 3 291
AUG 12 0 0 0 15 10 37
SEP 15 4 0 0 0 2 21
OCT 10 5 25 0 46 0 86
NOV 1,098 1,447 0 0 1,837 7 4,389
DEC 357 167 0 0 331 8 863
135 135 3 0 281 8 562
1,615 1,623 40 0 3,376 95 6,749
321 416 8 0 504 8 1,227
90% 90% 90% 90% 90% 90% 90%
1.28 1.28 1.28 1.28 1.28 1.28 1.28
411 533 10 0 646 11 1,572
TAHUN BULANPEMAKAIAN TYPE MATERIAL
2017
AVERAGE
TOTAL
STD DEV
SERVICE LEVEL
SERVICE FACTOR
SAFETY STOCK
A B C D E F TOTAL
JAN 488 540 8 0 738 5 1,779
FEB 648 718 3 0 969 7 2,344
MAR 498 475 4 0 679 7 1,662
APR 545 577 5 0 795 6 1,928
MAY 563 590 4 0 814 6 1,978
JUN 535 547 4 0 763 6 1,856
JUL 548 572 4 0 791 6 1,921
AUG 549 570 4 0 789 6 1,918
SEP 544 563 4 0 781 6 1,898
OCT 547 568 4 0 787 6 1,913
NOV 546 567 4 0 786 6 1,910
DEC 546 566 4 0 785 6 1,907
546 571 4 0 790 6 1,918
6,556 6,853 53 0 9,478 75 23,015
39 55 1 0 66 0 158
90% 90% 90% 90% 90% 90% 90%
1.28 1.28 1.28 1.28 1.28 1.28 1.28
50 70 2 0 85 1 202
SERVICE LEVEL
SERVICE FACTOR
SAFETY STOCK
STD DEV
BULANPEMAKAIAN TYPE MATERIAL
2018
AVERAGE
TOTAL
TAHUN
Tahun MaterialPemakaian
EA
Safety
Stock
Lead
TimeROP
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,355 222 60.00 445
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'10 1 60.00 3
SUCKER ROD, SIZE 3/4
IN, 25 FT, D1,293 233 60.00 446
SUCKER ROD, SIZE 7/8
IN, 25 FT, D1,861 171 60.00 477
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R22,733 275 60.00 724
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT109 12 60.00 30
2016
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 439
Table 15:- Calculation of Return Booking (ROP) for Use of
2017
Table 16:- Calculation of Re-Ordering (ROP) Usage in 2018
Table 17:- Calculation of Maximum Inventory (maximum
inventory) for use in 2016
Table 18:- Calculation of Maximum Inventory (maximum
inventory) for use in 2017
Table 19:- Maximum Inventory Calculation (Maximum
Inventory) Usage in 2018
Table 20:- EOQ Value, Safety Stock, ROP and Maximum
Material Inventory Inventory in 2016
Tahun MaterialPemakaian
EA
Safety
Stock
Lead
TimeROP
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,615 411 60.00 676
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'1,623 533 60.00 800
SUCKER ROD, SIZE 3/4
IN, 25 FT, D40 10 60.00 17
SUCKER ROD, SIZE 7/8
IN, 25 FT, D10 0 60.00 2
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R23,376 646 60.00 1,201
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT95 11 60.00 27
2017
Tahun MaterialPemakaian
EA
Safety
Stock
Lead
TimeROP
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'6,556 50 60.00 1,128
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'6,853 70 60.00 1,196
SUCKER ROD, SIZE 3/4
IN, 25 FT, D53 2 60.00 11
SUCKER ROD, SIZE 7/8
IN, 25 FT, D0 0 60.00 0
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R29,478 85 60.00 1,643
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT75 1 60.00 13
2018
Tahun MaterialPemakaian
EA
Safety
StockEOQ Max Inv
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,355 222 478 700
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'10 1 38 39
SUCKER ROD, SIZE 3/4
IN, 25 FT, D1,293 233 548 781
SUCKER ROD, SIZE 7/8
IN, 25 FT, D1,861 171 638 809
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R22,733 275 625 900
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT109 12 124 136
2016
Tahun MaterialPemakaian
EA
Safety
StockEOQ Max Inv
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'1,615 411 522 933
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'1,623 533 487 1,020
SUCKER ROD, SIZE 3/4
IN, 25 FT, D40 10 96 106
SUCKER ROD, SIZE 7/8
IN, 25 FT, D10 0 47 47
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R23,376 646 694 1,340
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT95 11 116 127
2017
Tahun MaterialPemakaian
EA
Safety
StockEOQ Max Inv
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'6,556 50 1,052 1,102
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'6,853 70 1,001 1,071
SUCKER ROD, SIZE 3/4
IN, 25 FT, D53 2 111 113
SUCKER ROD, SIZE 7/8
IN, 25 FT, D0 0 0 0
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R29,478 85 1,163 1,248
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT75 1 103 104
2018
Tahun Material EOQFreq.
Pemesanan
Safety
StockROP
Max
Inv
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,3/4 X25'478 3 222 445 700
ROD,SUCKER,MLD,3EA
STEALTH-XL,D,7/8 X25'38 0 1 3 39
SUCKER ROD, SIZE 3/4
IN, 25 FT, D548 2 233 446 781
SUCKER ROD, SIZE 7/8
IN, 25 FT, D638 3 171 477 809
TUBING, 2.7/8 IN, J-55,
6.5 PPF, EUE, R2625 4 275 724 900
BALL & SEAT 1.3/4IN
FLAT CARBIDE SEAT124 1 12 30 136
2016
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 440
Table 21:- EOQ Value, Safety Stock, ROP and Maximum
Material Inventory Inventory in 2017
Table 22:- EOQ Value, Safety Stock, ROP and Maximum
Material Inventory Inventory in 2018
Table 23:- Value of Total Inventory Cost (TIC) of the EOQ
Method in 2016
Table 24:- Value of Total Inventory Cost (TIC) of the EOQ
Method in 2017
Table 25:- Value of the Total Inventory Cost (TIC) of the
EOQ Method in 2018
Table 26:- Value of Total Inventory Cost (TIC) Existing
Method 2016
Table 27:- Value of Total Inventory Cost (TIC) of the
Existing Method of 2017
Tahun Material EOQFreq.
Pemesanan
Safety
StockROP
Max
Inv
ROD,SUCKER,MLD
,3EA STEALTH-
XL,D,3/4 X25'
522 3 411 676 933
ROD,SUCKER,MLD
,3EA STEALTH-
XL,D,7/8 X25'
487 3 533 800 1,020
SUCKER ROD, SIZE
3/4 IN, 25 FT, D96 0 10 17 106
SUCKER ROD, SIZE
7/8 IN, 25 FT, D47 0 0 2 47
TUBING, 2.7/8 IN, J-
55, 6.5 PPF, EUE, R2694 5 646 1,201 1,340
BALL & SEAT
1.3/4IN FLAT
CARBIDE SEAT
116 1 11 27 127
2017
Tahun Material EOQFreq.
Pemesanan
Safety
StockROP
Max
Inv
ROD,SUCKER,MLD
,3EA STEALTH-
XL,D,3/4 X25'
1,052 6 50 1,128 1,102
ROD,SUCKER,MLD
,3EA STEALTH-
XL,D,7/8 X25'
1,001 7 70 1,196 1,071
SUCKER ROD, SIZE
3/4 IN, 25 FT, D111 0 2 11 113
SUCKER ROD, SIZE
7/8 IN, 25 FT, D0 0 0 0 0
TUBING, 2.7/8 IN, J-
55, 6.5 PPF, EUE, R21,163 8 85 1,643 1,248
BALL & SEAT
1.3/4IN FLAT
CARBIDE SEAT
103 1 1 13 104
2018
Tahun MaterialPemakaian
EA
Harga/
EA
Biaya
Pesan
Biaya
SimpanEOQ TIC
A 1,355 1,777,552 15,000,000 10% 478 85,004,394
B 10 2,050,394 15,000,000 10% 38 7,842,947
C 1,293 1,290,000 15,000,000 10% 548 70,738,321
D 1,861 1,372,001 15,000,000 10% 638 87,520,749
E 2,733 2,101,442 15,000,000 10% 625 131,262,039
F 109 2,110,812 15,000,000 10% 124 26,272,334
2016
Tahun MaterialPemakaian
EAHarga/ EA Biaya Pesan
Biaya
SimpanEOQ TIC
A 1,615 1,777,552 15,000,000 10% 522 92,802,140
B 1,623 2,050,394 15,000,000 10% 487 99,916,807
C 40 1,290,000 15,000,000 10% 96 12,441,865
D 10 1,372,001 15,000,000 10% 47 6,415,608
E 3,376 2,101,442 15,000,000 10% 694 145,888,329
F 95 2,110,812 15,000,000 10% 116 24,527,157
2017
Tahun MaterialPemakaian
EA
Harga/
EA
Biaya
Pesan
Biaya
SimpanEOQ TIC
A 6,556 1,777,552 15,000,000 10% 1,052 186,984,719
B 6,853 2,050,394 15,000,000 10% 1,001 205,311,882
C 53 1,290,000 15,000,000 10% 111 14,291,536
D 0 1,372,001 15,000,000 10% 0 #DIV/0!
E 9,478 2,101,442 15,000,000 10% 1,163 244,438,717
F 75 2,110,812 15,000,000 10% 103 21,801,078
2018
Tahun MaterialAvg
Pemakaian
Biaya
Pesan
Biaya
SimpanTIC
A 113 15,000,000 177,755 200,071,502
B 0 15,000,000 205,039 180,068,346
C 108 15,000,000 129,000 193,889,000
D 155 15,000,000 137,200 201,277,433
E 228 15,000,000 210,144 227,860,296
F 9 15,000,000 211,081 181,917,319
2016
Tahun MaterialAvg
Pemakaian
Biaya
Pesan
Biaya
SimpanTIC
A 135 15,000,000 177,755 203,922,881
B 135 15,000,000 205,039 207,731,525
C 3 15,000,000 129,000 180,430,000
D 0 15,000,000 137,200 180,000,000
E 281 15,000,000 210,144 239,120,512
F 8 15,000,000 211,081 181,671,058
2017
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 441
Table 28:- Value of Total Inventory Cost (TIC) Existing
Method 2018
Table 29:- The Savings Value of the Total Inventory Cost
(TIC) of the Existing Method and the 2016 EOQ Method
Table 30:- Savings Value of Total Inventory Cost (TIC) of
Existing Methods and 2017 EOQ Method
Table 31:- Value of Savings for Total Inventory Cost (TIC)
of Existing Methods and Method of EOQ 2018
Graph 7:- Total Inventory Cost (TIC) Material A EOQ
Method 2016
Graph 8:- Total Inventory Cost (TIC) EOQ Method Material
A 2017
Graph 9:- Total Inventory Cost (TIC) Material A EOQ
Method in 2018
Graph 10:- Total Inventory Cost (TIC) Material B EOQ
Method 2016
Tahun MaterialAvg
Pemakaian
Biaya
Pesan
Biaya
SimpanTIC
A 546 15,000,000 177,755 277,120,236
B 571 15,000,000 205,039 297,091,352
C 4 15,000,000 129,000 180,567,356
D 0 15,000,000 137,200 180,000,000
E 790 15,000,000 210,144 345,972,859
F 6 15,000,000 211,081 181,320,240
2018
Tahun MaterialPemakaian
EA
TIC
Perusahaan
TIC
EOQ
SELISIH
Rp
A 1,355 200,071,520 85,004,394 115,067,125
B 10 180,068,346 7,842,947 172,225,399
C 1,293 193,889,000 70,738,321 123,150,679
D 1,861 201,277,433 87,520,749 113,756,684
E 2,733 227,860,296 131,262,039 96,598,257
F 109 181,917,319 26,272,334 155,644,985
1,185,083,914 408,640,785 776,443,130
2016
TOTAL
Tahun MaterialPemakaian
EA
TIC
Perusahaan
TIC
EOQ
SELISIH
Rp
A 1,615 203,922,881 92,802,140 111,120,741
B 1,623 207,731,525 99,916,807 107,814,717
C 40 180,430,000 12,441,865 167,988,135
D 10 180,000,000 6,415,608 173,584,392
E 3,376 239,120,512 145,888,329 93,232,183
F 95 181,671,058 24,527,157 157,143,901
1,192,875,976 381,991,907 810,884,069
2017
TOTAL
Tahun MaterialPemakaian
EA
TIC
Perusahaan
TIC
EOQ
SELISIH
Rp
A 6,556 277,120,236 186,984,719 90,135,517
B 6,853 297,091,352 205,311,882 91,779,470
C 53 180,567,356 14,291,536 166,275,820
D 0 180,000,000 0 0
E 9,478 345,972,859 244,438,717 101,534,143
F 75 181,320,240 21,801,078 159,519,163
1,462,072,044 672,827,931 609,244,112TOTAL
2018
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 442
Graph 11:- Total Inventory Cost (TIC) Material B EOQ
Method 2017
Graph 12:- Total Inventory Cost (TIC) Material EOQ
Method B in 2018
Graph 13:- Total Inventory Cost (TIC) Material C EOQ
Method 2016
Graph 14:- Total Inventory Cost (TIC) Material C EOQ
Method 2017
Graph 15:- Total Inventory Cost (TIC) Material C EOQ
Method in 2018
Graph 16:- Total Inventory Cost (TIC) Material EOQ
Method D in 2016
Graph 17:- Total Inventory Cost (TIC) Material EOQ
Method D 2017
Graph 18:- Total Inventory Cost (TIC) Material EOQ
Method D in 2018
Volume 4, Issue 1, January – 2019 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
IJISRT19JA148 www.ijisrt.com 443
Graph 19:- Total Inventory Cost (TIC) Material EOQ
Method E 2016
Graph 20:- Total Inventory Cost (TIC) EOQ Method
Material E 2017
Graph 21:- Total Inventory Cost (TIC) Material EOQ
Method E in 2018
Graph 22:- Total Inventory Cost (TIC) Material EOQ
Method F in 2016
Graph 23:- Total Inventory Cost (TIC) Material EOQ
Method F 2017
Graph 24:- Total Inventory Cost (TIC) Material EOQ
Method F in 2018
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