Tahapan selanjutnya yaitu membuat master schedule work sheet atau lembar DRP untuk CSF yaitu PT. Tirta Sibayakindo. Pada DRP PT. Tirta
Sibayakindo, Projected on Hand Past Due-nya adalah jumlah Planned Shipments - Receipt Date dari keempat distributor pada tiap periode dan lead time
produksi yaitu satu hari. Economic order quantity dan safty stock untuk CSF PT. Tirta Sibayakindo dapat dilihat melalui perhiungan dibawah ini:
Perhitungan EOQ dilakukan dengan menggunakan rumus berikut:
Berikut perhitungan EOQ untuk masing-masing produk: a. CSF untuk 240 ml
D = 231.814 kotaktahun k = Rp 248.500pesan
h = Rp.5.000
= 4.800 kotakpesan
5.32. Rekapitulasi Perhitungan EOQ untuk CSF PT. Tirta Sibayakindo Central Supply
Facility Produk ml EOQ
TSML 240
4.800 600
5.416 1500
3.835
Universitas Sumatera Utara
Perhitungan safety stock yang dipakai adalah sebagai berikut:
Safety Stock = s x Z Hasil perhitungan safety stock untuk CSF PT. Tirta Sibayakindo dapat
dilihat pada tabel 5.33.
5.33. Rekapitulasi Perhitungan Safty Stok untuk CSF PT. Tirta Sibayakindo Central Supply
Facility Produk ml Safety Stock
TSML 240
3.011 600
3.479 1500
2.089
Langkah-langkah pengisian Distribution Requirement Planning Sheet untuk CSF 240 ml adalah:
1. On Hand Balance = 10.000 Status persediaan awal CSF Tirta Sibayakindo 2. Lead Time = 1 hari
≈ 0 week Lead Time pendistribusian produk dari CSF Tirta Sibayakindo ke lantai produksi
3. OrderQuantity = 4.800 kotak diperoleh dari Tabel 5.32. 4. Safety Stock = 3.011 kotak diperoleh dari Tabel 5.33.
5. Projected on Hand Past Due = 10.000 kotak diperoleh dari On Hand Balance
6. Demands Forecast1
st
Week = 11.165 kotak diperoleh dari Tabel 5.29. 7. In Transit 1
st
Week = 0, tidak adanya produk yang sedang dalam proses pengiriman
8. Planned Shipments - Ship Date = 4.800 kotak diperoleh dari Order Quantity
Universitas Sumatera Utara
9. Planned Shipments - Receipt Date = 4.800 kotak diperoleh dari Order Quantity
10. Projected on Hand 1
st
Week = Projected on Hand Past Due + Order Quantity
– Demands Forecast 1
st
Week = 10.000 + 4.800 – 11.165 = 3.635
kotak 11. Perhitungan Distribution Requirement Planning Sheet untuk central supply
facility hingga minggu ke 52 dapat dilihat pada tabel 5.34.
Universitas Sumatera Utara
Tabel 5.34. Distribution Requirement Planning Sheet untuk CSF 240 ml
Distribution Requirement Planning Sheet untuk CSF 240 ml
On Hand Balance : 10.000
Lead Time :1hari
≈ 0 week Safety Stock
: 3.011 Order Quantity
: 4.800 Central Supply Facility
: Tirta Sibayakndo
Past Due
Week 1
2 3
4 5
6 7
8 9
10 11
12 13
Demands Forecast 11.165
2.991 8.174
2.991 5.525
5.640 2.991
5.525 2.649
8.515
In Transit Projected on Hand
10.000 3.635
3.635 5.444
6.872 3.881
3.156 7.116
4.125 3.400
5.551 5.551
6.636 6.636
Planned Shipments - Receipt Date 4.800
4.800 9.600
9.600 4.800
4.800 4.800
4.800 4.800
Planned Shipments - Ship Date
4.800 4.800
9.600 9.600
4.800 4.800
4.800 4.800
4.800
Past Due
Week 14
15 16
17 18
19 20
21 22
23 24
25 26
Demands Forecast 4.669
6.496 11.165
2.991 2.020
9.145 2.020
2.991 6.154
5.011 3.505
In Transit Projected on Hand
6.636 6.767
5.071 5.071
3.505 5.315
3.295 3.750
6.530 3.539
6.985 6.774
6.774 3.269
Planned Shipments - Receipt Date 4.800
4.800 9.600
4.800 9.600
4.800 9.600
4.800
Planned Shipments - Ship Date 4.800
4.800 9.600
4.800 9.600
4.800 9.600
4.800
Past Due
Week 27
28 29
30 31
32 33
34 35
36 37
38 39
Demands Forecast 7.660
2.991 6.154
5.011 3.505
7.660 8.516
2.649 2.991
5.525 2.991
2.649
In Transit Projected on Hand
3.269 5.209
7.018 5.664
5.453 6.748
3.888 3.888
4.972 7.123
4.132 3.407
5.216 7.367
Planned Shipments - Receipt Date 9.600
4.800 4.800
4.800 4.800
4.800 9.600
4.800 4.800
4.800 4.800
Planned Shipments - Ship Date 9,600
4.800 4.800
4.800 4.800
4.800 9.600
4.800 4.800
4.800 4.800
Past Due
Week 40
41 42
43 44
45 46
47 48
49 50
51 52
Demands Forecast 8.515
7.660 3.505
2.991 8.174
2.991 2.020
9.145 5.011
6.154 5.011
In Transit Projected on Hand
7.367 3.652
3.652 5.592
6.887 7.131
3.757 5.566
3.546 4.001
4.001 3.790
7.236 7.025
Planned Shipments - Receipt Date 4.800
9.600 4.800
4.800 4.800
4.800 9.600
4.800 9.600
4.800
Planned Shipments - Ship Date 4.800
9.600 4.800
4.800 4.800
4.800 9.600
4.800 9.600
4.800
Universitas Sumatera Utara
Langkah-langkah pengisian Distribution Requirement Planning Sheet untuk CSF 600 ml adalah:
1. On Hand Balance = 12.000 Status persediaan awal CSF Tirta Sibayakindo 2. Lead Time = 1 hari
≈ 0 week Lead Time pendistribusian produk dari CSF Tirta Sibayakindo ke lantai produksi
3. OrderQuantity = 5.416 kotak diperoleh dari Tabel 5.32. 4. Safety Stock = 3.479 kotak diperoleh dari Tabel 5.33.
5. Projected on Hand Past Due = 12.000 kotak diperoleh dari On Hand Balance
6. Demands Forecast1
st
Week = 12.498 kotak diperoleh dari Tabel 5.30. 7. In Transit 1
st
Week = 0, tidak adanya produk yang sedang dalam proses pengiriman
8. Planned Shipments - Ship Date = 5.416 kotak diperoleh dari Order Quantity
9. Planned Shipments - Receipt Date = 5.416 kotak diperoleh dari Order Quantity
10. Projected on Hand 1
st
Week = Projected on Hand Past Due + Order Quantity
– Demands Forecast 1
st
Week = 12.000 + 5.416 – 12.498 = 4.918
kotak 11. Perhitungan Distribution Requirement Planning Sheet untuk central supply
facility hingga minggu ke 52 dapat dilihat pada tabel 5.35.
Universitas Sumatera Utara
Tabel 5.35. Distribution Requirement Planning Sheet untuk CSF 600 ml
Distribution Requirement Planning Sheet untuk CSF 600 ml
On Hand Balance :12.000
Lead Time : 4 hari
≈ 0 week Safety Stock
: 3.479 Order Quantity
: 5.416 Central Supply Facility
: Tirta Sibayakindo
Past Due
Week 1
2 3
4 5
6 7
8 9
10 11
12 13
Demands Forecast 12.498
9.330 6.466
6.032 6.466
9.330 8.589
3.909 3.298
12.498
In Transit Projected on Hand
12.000 4.918
4.918 6.420
5.370 4.754
3.704 5.205
5.205 7.449
3.540 5.658
3.992 3.992
Planned Shipments - Receipt Date 5.416
10.832 5.416
5.416 5.416
10.832 10.832
10.832
Planned Shipments - Ship Date
5.416 10.832
5.416 5.416
5.416 10.832
10.832 10.832
Past Due
Week 14
15 16
17 18
19 20
21 22
23 24
25 26
Demands Forecast 5.421
10.375 12.498
3.298 12.498
9.330 6.466
9.330 3.168
5.421
In Transit Projected on Hand
3.992 3.987
4.444 4.444
7.578 4.280
7.414 7.414
3.500 7.866
7.866 3.952
6.200 6.195
Planned Shipments - Receipt Date 5.416
10.832 15.632
15.632 5.416
10.832 5.416
5.416 5.416
Planned Shipments - Ship Date 5.416
10.832 15.632
15.632 5.416
10.832 5.416
5.416 5.416
Past Due
Week 27
28 29
30 31
32 33
34 35
36 37
38 39
Demands Forecast 7.207
6.466 6.032
6.466 9.330
7.077 5.421
3.909 3.298
2.123 7.207
3.168 5.421
In Transit Projected on Hand
6.195 4.404
3.354 8.154
7.104 8.606
6.945 6.940
8.447 5.149
8.442 6.651
3.483 8.894
Planned Shipments - Receipt Date 5.416
5.416 10.832
5.416 10.832
5.416 5.416
5.416 5.416
5.416 10.832
Planned Shipments - Ship Date 5.416
5.416 10.832
5.416 10.832
5.416 5.416
5.416 5.416
5.416 10.832
Past Due
Week 40
41 42
43 44
45 46
47 48
49 50
51 52
Demands Forecast 6.032
6.466 3.909
6.466 5.421
7.077 5.421
7.077 3.298
2.123 10.375
2.123
In Transit Projected on Hand
8.894 8.278
7.228 8.735
7.685 7.680
6.019 6.014
4.353 6.471
4.348 4.805
8.098 8.098
Planned Shipments - Receipt Date 5.416
5.416 5.416
5.416 5.416
5.416 5.416
5.416 5.416
10.832 5.416
Planned Shipments - Ship Date 5.416
5.416 5.416
5.416 5.416
5.416 5.416
5.416 5.416
10.832 5.416
Universitas Sumatera Utara
Langkah-langkah pengisian Distribution Requirement Planning Sheet untuk CSF 1500 ml adalah:
1. On Hand Balance = 10.000 Status persediaan awal CSF Tirta Sibayakindo 2. Lead Time = 1 hari
≈ 0 week Lead Time pendistribusian produk dari CSF Tirta Sibayakindo ke lantai produksi
3. OrderQuantity = 3.835 kotak diperoleh dari Tabel 5.32. 4. Safety Stock = 2.089 kotak diperoleh dari Tabel 5.33.
5. Projected on Hand Past Due = 10.000 kotak diperoleh dari On Hand Balance
6. Demands Forecast1
st
Week = 9.045 kotak diperoleh dari Tabel 5.31. 7. In Transit 1
st
Week = 0, tidak adanya produk yang sedang dalam proses pengiriman
8. Planned Shipments - Ship Date = 3.835 kotak diperoleh dari Order Quantity
9. Planned Shipments - Receipt Date = 3.835 kotak diperoleh dari Order Quantity
10. Projected on Hand 1
st
Week = Projected on Hand Past Due + Order Quantity
– Demands Forecast 1
st
Week = 10.000 + 3.835 – 9.045 = 4.790
kotak 11. Perhitungan Distribution Requirement Planning Sheet untuk central supply
facility hingga minggu ke 52 dapat dilihat pada tabel 5.36.
Universitas Sumatera Utara
Tabel 5.36. Distribution Requirement Planning Sheet untuk CSF 1500 ml
Distribution Requirement Planning Sheet untuk CSF 1500 ml
On Hand Balance :10.000
Lead Time : 1 hari
≈ 0 week Safety Stock
: 2.089 Order Quantity
: 3.835 Central Supply Facility
: Tirta Sibayakindo
Past Due
Week 1
2 3
4 5
6 7
8 9
10 11
12 13
Demands Forecast 9.045
3.722 5.323
2.332 1.390
2.990 4.665
3.722 5.323
1.390 2.332
In Transit Projected on Hand
10.000 4.790
4.790 4.903
3.415 4.918
3.528 4.373
3.543 3.543
3.656 2.168
4.613
Planned Shipments - Receipt Date 3.835
3.835 3.835
3.835 3.835
3.835 3.835
3.835 3.835
Planned Shipments - Ship Date
3.835 3.835
3.835 3.835
3.835 3.835
3.835 3.835
3.835
Past Due
Week 14
15 16
17 18
19 20
21 22
23 24
25 26
Demands Forecast 2.990
2.332 3.723
2.990 2.332
1.390 7.655
3.722 2.333
2.990 2.332
In Transit Projected on Hand
2.281 3.126
4.629 4.629
5.474 3.142
5.587 5.602
5.602 5.715
3.382 4.227
5.730 5.730
Planned Shipments - Receipt Date 3.835
3.835 3.835
3.835 3.835
7.670 3.835
3.835 3.835
Planned Shipments - Ship Date 3.835
3.835 3.835
3.835 3.835
7.670 3.835
3.835 3.835
Past Due
Week 27
28 29
30 31
32 33
34 35
36 37
38 39
Demands Forecast 6.713
2.332 6.713
2.332 6.712
2.333 2.332
2.990 3.723
2.332
In Transit Projected on Hand
5.730 2.852
4.355 4.355
5.312 2.980
2.980 3.938
5.440 3.108
4.065 4.174
5.677 5.677
Planned Shipments - Receipt Date 3.835
3.835 7.670
7.670 3.835
3.835 3.835
3.835
Planned Shipments - Ship Date 3.835
3.835 7.670
7.670 3.835
3.835 3.835
3.835
Past Due
Week 40
41 42
43 44
45 46
47 48
49 50
51 52
Demands Forecast 2.990
2.332 3.723
5.322 4.665
4.380 4.665
2.990 3.722
In Transit Projected on Hand
5.677 2.687
4.190 4.302
2.815 2.815
5.820 5.275
5.275 4.445
4.445 5.290
5.430 5.430
Planned Shipments - Receipt Date 3.835
3.835 3.835
7.670 3.835
3.835 3.835
3.835
Planned Shipments - Ship Date 3.835
3.835 3.835
7.670 3.835
3.835 3.835
3.835
Universitas Sumatera Utara
I-116
BAB VI ANALISIS PEMECAHAN MASALAH
6.1. Analisis Hasil Peramalan Permintaan
Distribution Center
Berdasarkan data permintaan 12 bulan sebelumnya yang dimulai dari November 2011 sampai dengan Oktober 2012 dilakukan peramalan pada masing-
masing distribution center untuk 12 bulan kedepan. Laju peramalan adalah suatu kumpulan peramalan yang telah diolah dengan bantuan software WinQSB 2.0
yang dapat disimpulkan berdasarkan hasil olahan sehingga penerapan Distribution Requirement Planning akan lebih efisien dan efektif. Adapun 12 metode yang
digunakan adalah : 25 Simple Average SA
26 Moving Average MA 27 Weight Moving Average WMA
28 Moving Average with Liniar Trend MAT 29 Single Exponential Smoothing SES
30 Single Exponential Smoothing with Trend SEST 31 Double Exponential Smoothing DES
32 Double Exponential Smoothing with Trend DEST 33 Adaptive Exponential Smoothing AES
34 Linier Regression with Time LR 35 Holt-Winters Additive Algorithm HWA
36 Holt-Winters Multiplicative Algorithm HWM
Universitas Sumatera Utara
