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    CONTOH PERHITUNGAN

    MANAJEMEN LOGISTIK

    Sekolah Tinggi Manajemen Bandung

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    UMUR EKONOMIS

    Umur ekonomis suatu aktiva tetap adalah suatu periode yang

    memberikan Equivalent Uniform Annual Cost (EUAC) minimum.Untuk mencari umur ekonomis, kita harus menghitung Total EUAC

    dimana k minimum, k = 1,2,3,4n

    Rumus Umum Umur Ekonomis :

    EUAC =

    P(A/P,i%,k)-Sk(A/F,i%,k)+[SAOCj(P/F,i%,k)](A/P,i%,k)

    Contoh :

    Sebuah Sentral Telepon Digital dibeli dengan harga $ 1.000.000.-Dengan perkiraan nilai sisa dan biaya operasi tahunan seperti tabel

    dibawah ini, jika diketahui MARR = 10 %, pada tahun berapa umur

    ekonomis sentral tersebut dicapai?

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    Year - k Salvage Value t Annual

    thn ke-n operatingcost

    1 900,000 100,000

    2 850,000 120,000

    3 800,000 120,000

    4 750,000 120,000

    5 700,000 125,000

    6 650,000 130,000

    7 600,000 140,000

    8 550,000 150,0009 500,000 200,000

    10 450,000 250,000

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    n (A/P,10%,k) (A/F,10%,K) (P/F,10%,K)1 1.1000 1.0000 0.9091

    2 0.5762 0.4762 0.8264

    3 0.4021 0.3021 0.7513

    4 0.3155 0.2155 0.68305 0.2638 0.1636 0.6209

    6 0.2298 0.1296 0.5645

    7 0.2054 0.1054 0.5132

    8 0.1874 0.0874 0.4665

    9 0.1736 0.0736 0.4241

    10 0.1627 0.0627 0.3855

    Factor bunga untuk membantu perhitungan

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    Year EUAC EUAC TOTAL

    k CAPITAL OPERA- EUAC

    RECOVERY TIONS

    1 200,000 100,001 300,001

    2 171,430 104,758 276,188

    3 160,420 102,713 263,133

    4 153,875 99,124 252,999

    5 149,280 95,819 245,099

    6 145,560 92,751 238,311

    7 142,160 90,127 232,287

    8 139,330 87,859 227,189

    9 136,800 88,717 225,51710 134,485 91,259 225,744

    Jadi Umur Ekonomis Sentral Digital tersebut adalah = 9 tahun

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    MODEL-MODEL PERSEDIAAN

    Variabel Model - P Model - Q

    Apa? Klasifikasi A-B-C

    Berapa? Maks.Persediaan = S Besar Pesanan = QKapan? Lama Periode = T Titik Pesan = R

    D = Besar pesanan setahun

    B = Biaya tiap pesani = %, interewst tahunanS = Unit price

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    Contoh :

    D = Besar pesanan setahun= 36.000 YARDS, 1 hari = 100YardsB = Biaya tiap pesan = Rp 1.000 tiap kali pesani = %, interest tahunan, 25 % per tahunS = Unit price, Rp 800 per yardsLT = Lead time

    DLT = Demand Lead Time, misal LT = 2 hari,DLT = 200 yards, makasetiap persedian mencapai200 yards harus segera dipesan sejumlah EOQ

    80025.0

    3600010002

    x

    xxEOQ

    SiDBEOQ

    .

    ..2

    EOQ = 600 yards tiap kali pesan, kebutuhan 1 hari = 100 YardsT = Periode = 600/100 = 6 hariBiaya pesan minimum = (360 hari/ 6 hari) x Rp 1000= Rp 60.000,-

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    A. LEAD TIME BERSIFAT POSITIF, DEMAND KONSTAN

    LT = Lead time

    DLT = Demand Lead Time, misal LT = 2 hari,DLT = 200 yards, makasetiap persedian mencapai 200 yardsharus segera dipesan sejumlah EOQ

    B. LEAD TIME BERSIFAT POSITIF, DEMAND KONSTAN

    Safety Stock = SS = DLT + ( Z X Standard Deviasi LT) D

    Misal : LT (rata-rata) = 2 hariStandard Deviasi = 1 hari

    Service level = 95 %

    Z = 1.65Demand per hari = D = 100 yards

    Maka SS = 200 + ( 1.65 x 100 ) = 365 yards.

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    C. LEAD TIME KONSTAN, DEMAND PROBABILISTIK

    Safety Stock = SS = DLT + ( Z X (LT X Standard Deviasi LT)Misal : Demand per hari (rata-rata) = D = 100 yards

    Standard Deviasi = 80 yards

    Lead Time = 2 hariService level = 95 % Z = 1.65

    Maka SS = 200 + ( 1.65 x (2 X 80 ) = 387 yards.

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    Diketahui : D = 10.000 unit per tahun

    B = $ 24 per pesananS = $ 3 per unitK = $ 4 per unit kekuranganX = 40 unit per hari distribusi normal

    dengan Standar Deviasi = 15 unitService level = 95 %

    LT = 7 hari, 1 tahun = 250 kari kerja,

    Dapat dihitung :a. Periode pesanan (T) = (2.B/D.S) = (2x24/10.000x3) = 0.04

    tahun = 10 hari

    b. Periode Perencanaan ( Y = T + TL ) = 10 + 7 = 17 haric. EOQ atau E = Y x X = 17 x 40 unit = 680 unitd. Sdy (SD Perencanaan) =( Y ) SDx = ( 17 ) x 15 = 62 unite. Maksimum Persediaan = S max = E + Z . (SDy)

    = 680 + 1.65 x 62 = 782 unit

    Contoh lain persediaan Model P

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    SERVICE LEVELPROBABILITY

    TOCK OUTPROBABILITY

    M R

    DISTRIBUSI PERMINTAAN SELAMA LEAD TIME

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    Hubungan Z dengan % Stock Out

    Z Service Level (%) Stock Out (%)

    0.0 50.0 50.0

    0.5 69.1 30.9

    1.0 84.1 15.9

    1.1 86.4 13.6

    1.2 88.5 11.5

    1.3 90.3 9.7

    1.4 91.9 8.1

    1.5 93.3 6.7

    1.6 94.5 5.5

    1.7 95.5 4.51.8 96.4 3.6

    1.9 97.1 2.9

    2.0 97.7 2.3

    2.1 98.2 1.8

    2.2 98.6 1.4

    2.3 98.9 1.12.4 99.2 0.8

    2.5 99.4 0.6

    2.6 99.5 0.5

    2.7 99.6 0.4

    2.8 99.7 0.3

    2.9 99.8 0.2

    3.0 99.9 0.1

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    Contoh Lain:

    Diketahui : D = 4.000 unit per tahun

    B = Rp 10.000,- per pesananS = Rp 10.000,-per unitOngkos penyimpanan = Rp 4000,- per th.=Cp

    Lead Time = 7 hari, 1 tahun = 365 kari

    Ditanya : Tentikan Reorder point, agar jumlah pemesanan (Q) minimal.

    Dapat dihitung :

    a. EoQ = (2.BD/Ongkos penyimpanan ) = (2x4000x10000)/4000 =141.4 unit =141 unit

    b. Titik Pembelian kembali = (TLxD)/365 =76,7 unit = 77 unit

    Jadi pemesanan sebanyak 141 unit bila inventory menurun sampai =77 unit

    c. Berapa kali pesanan per tahun = D/Q =4000/141 kali = 28 kalid. Periode pesanan (lama antar pesanan) = 365 hari/jumlah pesanan

    per tahun = 365/28 = 13 hari.

    2BxDQ = ---------

    Cp

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    Manajemen Material ( MM )

    Peranan MM :

    Mengurangi biaya materal

    Memperbaiki ROI :

    Profit Sales

    ROI = ------------ x --------------------------------------------

    Sales Fixed Asset + Current Asset

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    Fungsi Manajemen Material ( MM )

    Perencanaan Materal

    Pengadaan Material

    Penyimpanan Material

    Pendistribusian Material

    Penghapusan Material

    Pengendalian Material

    Quality ( material yang tepat)Reasonable Cost (harga wajar)

    Delivery ( Waktu/saat tepat)FlexibleService level

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    Manajemen Material ( MM )

    Persoalan Persediaan Tradisoional Persediaan KebutuhanMaterial

    Objek Komponen Produk

    Data Penglaman masa lalu Keterkaitan antar

    komponenOrientasi Masa lalu Masa y.a.d

    Metode Statistik Komputasi

    Pemakaian Independent Demand Dependent demand

    Asumsi Pemakaian uniform Pemakaian (bisa grdual)

    Pesanan Reorder Point atau waktupesan tetap

    Sesuai kebutuhan

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    Persediaan Tradisional

    Dasar Kebijakan

    Pola permintaan : Probabilisti - Deterministik

    Statis - Dinamis

    Pola Pengadaan : Sekaligus Bertahap - Kontinu

    Lead Time : Deterministik - Probabilistik

    Kendala Fisik : Gudang

    transportasi - dllStruktur Biaya : Biaya Pengadaan (B)

    Biaya Penyimpanan (S)

    Biaya Kekurangan Persediaan (K)

    Pola Manajemen : Kebijakan Delivery, CaraPembayaran

    Pencatatan Biaya, dll

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    Logistical Management

    CH.8 : INVENTORY STRATEGY &

    CH.9 : INVENTORY MANAGEMENT

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    Chapter. 8 :

    INVENTORY STRATEGY

    High risk and high impact

    Sales lost and customer satisfaction declineOver stock may increase cost and reduce

    profitability

    Inventory type and characteristics

    Basic inventory decision rules

    Uncertainty

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    Chapter. 8 :

    INVENTORY STRATEGY

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    Relation between formulating inventory andmanufacturing / marketing .Inventory as a % (percentages) of assetsOpportunity of increasing inventory productivity

    vs. integrated supply chains ability to useinformation exchange and management focus toreduce uncertainty

    Chapter. 8 :

    INVENTORY STRATEGY

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    1. Inventory functionality andprinciples

    a. Inventory type and characteristicsb. Inventory functionalityc. Inventory related definitionsd. Cost of carrying inventory

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    1. Inventory functionalityand principles

    A. Inventory type and characteristicsInventory risk due to capital investment and

    potential for obsolescenceI. Investment of inventory

    II. Possibility of risk

    Nature of risk is vary depend on an enterprises position inthe distribution channel. :a. Manufacturing long term dimension

    b. Wholesalenarrow but deeper and longer duration

    c. Retailer wide but not deep.

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    1. Inventory functionality andprinciples

    Inventory functionality

    1) Geographical Specialization - resources vs. distance need

    individual operating unit2) Decoupling - provide maximum operating efficiency, the process

    permit each product to be manufactured and distribute in economical

    lots size.

    3) Balancing supply and demand - is concern with elapsedtime between consumption and manufacturing, its reconcile supply

    availability with demand

    4) Buffer uncertainty- the safety stock or buffer stock functionconcern short range variation in either demand or replenishment. Its

    protect two type uncertainty : forecast and delay

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    C. Inventory related definitionsInventory Policy - guide line what to purchase and manufacture, whenand what quantity

    Service Levelis target specified by management.it defined theperformance objectivesAverage Inventory - consist of material, components, W-I-P, and finished

    goods typically stocked in logistical facilities

    Cycle inventoryis the portion of average inventory that result from

    replenishment processSafety stock inventory - the second part of average inventoryheld to

    protect against uncertainty on each facility

    Transit inventorystock in moving or awaiting for transportation

    Inventory functionality and principles

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    Example of average inventory overperformance cycle

    200

    100

    0 20 40 60

    days

    Averageinventory

    Orderplacement

    Orderarrival

    inventory

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    :Assume the following condition :i. Replenishment cycle20 days

    ii. Sales rate during replenishment10 unitsiii. Ordering upon deliveryiv. Replenishment order quantity200 units

    Figure 8.2 is called , rate sales is 10 units per day

    and take 20 days to complete inventory replenishment,its mean that order 200 units every 20 days.Formulation :Reorder point is specified as 200units on hand whatever happened

    Average inventory100 units, since stock on hand is 100 units.

    Assume that work days is 240 days a year, so 12 time ofpurchase is needed during one year.Sales 10 units per day , so became 2400 per yearThus became 2400 divided by 100 unit =

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    What happen if order more frequently than onceevery 20 days?Order 100 units every 10 days? Or 600 units every 60 days?

    Assuming that inventory cycle is constant 20 days.The policy of ordering 600 units every 60 days would resultthat average inventory became 300 units and turn over

    became 2400units/300units = 8

    If the order 100 units per 10 days means that two orderbe outstanding. Thus reorder point remain 200 units

    Average inventory became 50 units

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    600

    300

    020 60 100

    Days

    Averageinventory

    Orderarrival

    inventory 400

    200

    40 80 120

    Figure 8.3 : Alternative order quantity andaverage inventory

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    100

    50

    0 20 40 60

    Orderplacement

    Orderarrival

    invento

    ry

    Averageinventory

    Figure 8.3 Alternative order quantityand

    average inventory

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    Inventory Carrying cost components :

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    PLANNING THE INVENTORY RESOURCES

    Basic reorder formula :

    Where R = Reorder point in unitsD = Average daily demandT = Average performance cycle length

    e.g Demand = 10 units per dayPerformance cycle = 20 days

    R = 10 units /day X 20 days = 200units

    With buffer stock or Safety Stock (SS)

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    Determine Lots Size byEconomic Order Quantity (EOQ )Formulation

    Remark :1) Co = cost per order2) Ci = annual inventory carrying cost3) D = annual sales volume, units

    4) U = cost per unit

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    Example using EOQ Formula

    Annual demand volume = 2400 units Unit value at cost = $ 5.00 Inventory carrying cost percentage = 20 % annually

    Ordering cost = $ 19.00 per order

    By substituting from above , we have :

    2 X 19 X 2400EOQ = ----------------------0.20 X 5.00

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    EOQ extension :

    EOQ formulation is straight forward, but there are some other factormust be considered in actual application : Volume transportation rates Quantity discountOther EOQ adjustment : (I) production lots size

    (ii) Multiple item purchase(iii) Limited capital(iv) Private trucking

    Discrete Lot SizingLot-for lot sizing

    Period order quantity ( POQ) EOQ = 300 unitsForecast per year = 2400 unitsOrder per year = 2400/300 = 8 timesOrder interval = 12/8 = 1.5 months

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    ACCOMMODATING UNCERTAINTY

    Forecast vs. actual

    Frequency demand

    Normal distributionStandard deviation

    Inventory policy can not assume consistent delivery

    Table 8.11

    Table 8.12

    MRP Formulae

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    Table 8-8 Typical Demand ExperienceDuring Replenishment Cycle

    -------------------------------------------------------------------------------------------------------Forecast cycle 1 Stock out cycle Over stock cycle 3------------------------------ ------------------------------ ------------------------------Day Demand Accum. Day Demand Accum Day Demand Acumm

    ------------------------------------------------------------------------------------------------------1 9 9 11 0 0 21 5 52 2 11 12 6 6 22 5 103 1 12 13 5 11 23 4 144 3 15 14 7 18 24 3 175 7 22 15 10 28 25 4 21

    6 5 27 16 7 35 26 1 227 4 31 17 6 41 27 2 248 8 39 18 9 50 28 8 329 6 45 19 so 50 29 3 3510 5 50 20 so 50 30 4 39--------------------------------------------------------------------------------------------------------

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    Table 8-9 Frequency of Demand

    ----------------------------------------------------------------------------------------------------Demand/day Frequency (days) Demand Frequency (days)--------------------------------------------- ----------------------------------------------

    Stockout 2 Five units 5Zero 1 Six units 3One unit 2 Seven units 3Two units 2 Eight units 2Three units 3 Nine Units 2

    Four Units 4 Te units 1

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    Historical analysis

    ofdemand history

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    Normal Distribution

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    Calculation of standard deviationof daily demand

    -------------------------------------------------------------------------------------Units Frequency Deviation Deviation

    from Mean Squared(FJ) (Di) (Di) FiDi

    ------------------------------------------------------------------------------------

    0 1 -5 25 251 2 -4 16 322 2 -3 9 183 3 -2 4 124 4 -1 1 45 5 0 0 0

    6 3 1 1 37 3 2 4 128 2 3 9 189 2 4 16 3210 1 5 25 25------------------------------------------------------------------------------------

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    s

    s

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    Chapter .9 :INVENTORY MANAGEMENT

    a) Inventory Control

    b) Reactive Method

    c) Planning Method

    d) Adaptive Logic

    a) Strategy Development Process

    b) Method of improvement Inventory Management

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    Chapter .9 :INVENTORY MANAGEMENT

    Chapter 8 focused on inventory decision for single item at a singlelocation, while chapter 9 discussed inventory management for a range ofSKUs (Stock Keeping Units) and at multiple location.

    Inventory management is the integrated process that operationalizes thefirms and the value chains inventory policy.

    Reactive approach or pull inventory approach, uses customer demandto pull product through the distribution channel

    Planning approach, - proactively schedule product movement,according to the forecast.

    Combination of two approach abov,respon to the product and marketenvironment

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    Inventory ControlInventory control is a mechanical procedure for implementing aninventory policy. Accountability and tracking should be done eithermanually or computerized. The primary differential are : speed,accuracyand cost.Inventory control procedure can be characterized as perpetual

    or periodic.A perpetual inventory control process reviews

    inventory status daily to determine replenishment needs, implementedthrough and .

    Order quantity determine using EOQ Formulation, EOQ extension oranother approach

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    Example :Average daily demand = 20 units

    Performance cycle = 10 daysOrder quantity = 200 unitsROP = D X T + SS SS = 0

    = 20 X 10 + 0 = 200 unitsThere are two type inventory in this case,

    on - order - inventory or inventory on order Qo and on - handinventory or inventory on hand I

    Mathematically we can say that :

    If I + Qo < ROP then order QAverage inventory can be calculate :

    I = Q/2 + SS I = 200/2 + 0 = 100

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    The formula for calculating periodic review reorder point :

    ROP = Reorder PointD = Average Daily DemandT = Average performance cycle lengthP = review period in days

    SS = Safety Staock

    The Average Inventory Formula for periodic is

    I = average inventory in units

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    To accommodate specific situation, variations and combinationsof the basic periodic and perpetual control systems have beenDeveloped. Most common are :

    The replenishment level system andThe optional replenishment system.

    The target of replenishment can be calculated by using thefollowing formula :

    Where : TGT = replenishment levelSS = Safety StockD = Average daily demandP = Review period in daysT = Average performance cycle length

    The General reorder rule became

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    The General reorder rule became

    Where : Q = order quantityTGT = Replenishment LevelI = Inventory Status at review timeQo = Quantity on order

    The Average Inventory became :

    Replenishment order can be guarantee at least be equal to

    the difference between max level (S) and min level (s)

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    Example :

    The minimum or (s) level is determined similarly to ROP,

    where there is no uncertainty

    When demand and performance-cycle uncertainty exist, the

    Minimum stock level (s) must be incremented by an allowance forsafety stock.For example both maximum and minimum are definedin term of specific number say 100 units and 400 units respectively,The result is :

    E.g : Quantity = 75 unitsQuantity on order = 0 unitsQuantity to order = 400750 = 325 units

    Reactive Methods

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    Reactive Methods

    Replenishment era initiated when stock levels fall bellowminimum or order point. The review to anticipate these condition,

    the following assuming and assumption should be discussed :i. The system should contribute equally profit.ii. Infinite availability at the source that means no constraints exist.iii. No constraint on facility capacity or inventory availability.iv. Performance cycle time can be predicted and independent.v. Demand pattern are relatively stable and consistent.

    Figure 9.1 explained reactive inventory environment.

    I 250ROP 200OQ 400 I 80

    ROP 75OQ 200D 14

    I 45ROP 50OQ 200

    D 5

    Resupply order for 200 units need for Ws A

    I ( current inventory) above ROP for Ws B

    Ws A more independentWs B will stock out because Inventory level

    close to ROP

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    Planning Method

    Use common information base to coordinate inventory requirementacross multiple locations or stages in the value added chain,Two type of planning method are commonly used :

    -> equitable inventory see Figure 9.2-> more sophisticated,

    similar with MRP see. Figure 9.3

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    Adaptive Logic

    A combined inventory management system may be use to overcomesome of the problem s in Reactive or Planning method.Description

    Adaptive decision factor

    Use proactive logic Use reactive logic- Highly profitable segment - Cycle time uncertainty

    - Dependent demand - Demand uncertainty- Economics of sales - Destination capacity limitations- Supply uncertainty- Source capacity limitations- Seasonal supply buildup

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    FUNGSI INVENTORY

    Menyelaraskan antara penyediaan dankebutuhan

    Menyelaraskan kebutuhan konsumen

    dengan barang jadiMenyelaraskan barang jadi dengankomponen pembentuknya

    Menyelaraskan kebutuhan operasi denganoutput dari operasi sebelumnya

    Menyelaraskan komponen dan bahan bakudengan supplier material

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    DILIHAT DARI FUNGSI DANPERANNYA INVENTORY DAPATDIBAGI MENJADI :

    Anticipation InventoryFluctuation Inventory

    Lot Size Inventory

    Transportation Inventory

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    Tujuan Manajemen Persediaan(Inventory Management)

    Maximum, customer service

    Low cost plant operationMinimum Inventory Investment

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    CUSTOMER SERVICE

    Availability

    Management effectiveness

    - percentage order shipped on schedule

    - percentage line items shipped on schedule

    - days of out of stocks

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    OPERATING EFFICIENCY

    Mengembangkan Inventory Investment

    dengan hal-hal berikut :1. Customer Service

    2. Biaya untuk merubah tingkat produksi

    : overtime, hiring, training, lay-off3. Ongkos pemesanan

    4. Ongkos transportasi

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    INVENTORY COST

    Item cost

    Carrying costOrdering cost

    Stock-out cost

    Capacity-Related cost

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    PENENTUANECONOMIC ORDER QUANTITY,

    RE ORDER POINT &SAFETY STOCK

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    Fixed Order Quantity Inventory System (System-Q).

    Diketahui :

    Kebutuhan Material pertahun =3.000 unit (D) Order Cost = $500 Perkali pesan (O)

    Harga Material = $ 30 per unit (M)

    Storage Cost/Carrying Cost / Holding cost = $ 3 /unit.tahun

    (C) 1 tahun terdiri dari 300 hari kerja

    Lead time 10 hari

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    Rata-rata kecepatan pemakaian material adalah10 unit perhari dengan simpangan baku(standard deviation)= 1,2 unit

    Service level : Diinginkan kemungkinanterjadinya Stock -Out adalah 0,05 atau 5 %

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    Ditanya :

    a. Economic Order Quantity

    b. Reorder Point

    c. Safety Stock

    d. Total Inventory Cost Pertahun

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    QuantityOrderEconomic1000*Q

    93,1251,12590,0002,000*T750*Q

    93,0001,50090,0001,500*T1000*Q

    93,2502,25090,0001,000*T1500*Q

    95,0004,50090,000500

    2

    3000x3

    30x30003000

    3000x500

    *T3000*

    Q

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    65

    EOQ

    $

    Order Cost

    Carrying Cost

    Total Cost (T*)

    Q*

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    Jawab :

    a. EOQ =

    b. Kebutuhan material pertahun = 3000 unitjumlah hari kerja pertahun = 300 hari

    jadi kebutuhan material rata-rata perhari

    = 3000 =10 unit/hari

    300

    Lead Time = 10 hari

    Reorder Point = kebutuhan selama lead time= 10 x 10 unit = 100 unit

    1000

    3

    30005002..2 xx

    C

    DO

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    c. Safety Stock = Z.SX

    Z = Nilai koefisien distribusi normal untuksevice level tertentu. Bila diinginkanProbabilitas Stock Out = 0,05(Probabilitas dapat terpenuhi kebutuhan

    material sebesar 0,95 ) maka Z= 1,65Sx = Deviasi standard pemakian material

    perhari =1,2 unit

    t = Lead time ( dalam hari ) = 10 hariSS= 1,65x1,2 x =6,26 unit

    t

    10

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    d. Total Inventory Cost pertahun

    =

    = 500 x 3000 + (3000 x 30) + (3 x 1000)+(6,26x3)

    1000 2

    Lt = 1500 + 90000+1500 + 18,78 = 93018,78

    OD x MD + CQ* + (SS). C

    Q* 2

    Fi d O d P i d i t t

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    Fixed Order Period inventory system( system P)

    Untuk soal yang sama dengan system Q, bila Rate

    pemakaian material konstan, maka system P dan Qmenunjukkan karakteristik yang sama, kecuali dalam

    penentuan safety stock nya. Dalam hal pemakaian material tidak sepenuhnya

    konstant, maka Order Quantity (Order size) bergantugkepada persediaan di gudang (inventory on hand) padasaat perioda pemesanan tiba.

    misalnya: Pada Suatu perioda pemesanan inventory onhand = 150 unit ( termasuk SS)

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    Safety stock = Z.S x

    Dimana t+r = waktu siklus = waktu rata-rata dari

    suatu pemesanan ke pemesanannya berikutnyadalam contoh t+r = EOQ

    kecepatan pemakaian perhari

    = 1000 = 100 hari10

    Dengan Faktor keamanan 0,95 maka diperoleh :

    SS= 1,65 x 1,2 x = 19,8 unit unit

    Order size = EOQ + SS - Inventroy on Hand +

    Pemakaian selama lead time

    = 1000 + 20 - 150 + 100 = 970 unit

    t r

    100 20