TAKARIR
Junbiki
: Faximili
Kanaban
: Kartu Perintah
Just In Time
: Produksi Tepat Waktu
Inventori
: Persediaan
Sub Kontrak
: Pesan Produksi
Supplier
: Pemasok
Tack time
: Waktu Respon
Cycle Time
: Waktu Siklus
Man Power
: Tenaga Kerja
Cost Reduction
: Penurunan Biaya
Delivery
: Pengiriman
Order
: Pesan
Heijunka Pattern
: Ururtan Produksi
Lead Time
: Waktu Tunggu Proses
One-Piece-Flow
: Produksi Mengalir
Muda
: Pemborosan
Mura
: Ketidakaturan
Muri
: Berlebihan
Work In Process
: Barang Setengah Jadi
Batch
: Kumpulan
Queue
: Menunggu
Lot Size
: Ukuran lot
Pulling System
: Sistem Tarik
Waste
: Sisa/ Pemborosan
Multifungsional
: Banyak Fungsi
Iteratif
: Berulang
Handling
: Penanganan
Lean Thingking
: Filosofi Mengalir
Flow Process
: Aliran Proses
xi
Bottleneck
: Penumpukan
Defect
: Rusak
Container
: Pembawa
Boundary
: Batasan
Sinektik
: Kesamaan
Elaborasi
: Bertahap
Resources
: Sumber Daya
Conveyor
: Ban Berjalan
Loading
: Unit Pemasukan
Error
: Kesalahan
Utility
: Penggunaan
Assembly
: Perakitan
Scrap
: Sampah/ Buangan
Breakdown
: Pemecahan
Part
: Bagian
Stock
: Simpanan
Production Time
: Waktu Produksi
Komprehensif
: Menyeluruh
Compress Time
: Hemat Waktu
Expand Time
:Meluaskan Waktu
Real System
: Sistem Nyata
Replicate
: Diperbanyak
Path Networks
: Jaringan lintasan kerja
Interval
: Jarak Antara
xii
DAFTAR SIMBOL
Tt
= Tack time (menit)
Tw
= Total waktu produksi (menit)
P
= Kebutuhan produksi (unit)
Lts
= Lead time proses (menit)
Qp
= Unit pemasukan untuk tack time (unit)
Lz
= Data lot size (menit)
Q
= Lot dalam 1 kali pengiriman (unit)
b
= Data lot size/ interval kedatangan truk (menit)
c
= Waktu pengiriman fax ke supplier (menit)
d
= Waktu loading di supplier (menit)
e
= Waktu pengiriman (menit)
f
= Waktu unloading di perusahaan (menit)
g
= Waktu supply ke line (menit)
Wi
= Selisih waktu amtara waktu proses>waktu informasi (menit)
W1
= Waktu proses (menit)
W2
= Waktu informasi (menit)
It
= Interval kedatangan truk (menit)
Tr
= Kebutuhan truk (unit)
Ct
= Cycle time (menit)
Cts = Total waktu siklus setiap proses (menit) xiii
Ub
= Unit pemasukan untuk cycle time (unit)
% Pf
= % perbandingan Perfoma tack time dengan cycle time (persen)
2
= Chi square test (unit)
Oi
= Data observasi (unit)
Ei
= Harga harapan
Er
= Standat errror
xiv
DAFTAR ISI
HALAMAN JUDUL ..................................................................................... i LEMBAR PENGAKUAN.............................................................................. ii SURAT KETERANGAN DARI PERUSAHAAN........................................ iii LEMBAR PENGESAHAN PEMBIMBING ................................................. iv LEMBAR PENGESAHAN PENGUJI .......................................................... v HALAMAN PERSEMBAHAN .................................................................... vi HALAMAN MOTTO .................................................................................... vii KATA PENGANTAR ................................................................................... viii ABSTRAK..... ................................................................................................ x TAKARIR...................................................................................................... xi DAFTAR SIMBOL........................................................................................ xiii DAFTAR ISI .................................................................................................. xv DAFTAR TABEL .......................................................................................... xx DAFTAR GAMBAR... .................................................................................. xxi BAB I PENDAHULUAN .............................................................................. 1 1.1
Latar Belakang ................................................................................. 1
1.2
Rumusan Masalah .............................................................................. 3
1.3
Batasan Masalah ................................................................................ 3
1.4
Tujuan Penelitian .............................................................................. 3
1.5
Manfaat Penelitian ............................................................................. 4
1.6
Sistematika Penulisan ........................................................................ 5
xv
BAB II TINJAUAN PUSTAKA ................................................................... 6 2.1
Metode Junbiki................................................................................... 6
2.2
Just In Time........................................................................................ 10
2.2.1
Pengertian JIT .................................................................................... 10
2.2.2
Latar Belakang Terjadinya JIT .......................................................... 12
2.2.3
Tujuan JIT .......................................................................................... 13
2.2.4
Syarat-Syarat Penerapan JIT .............................................................. 15
2.2.5
Komponen-Komponen JIT ................................................................ 16
2.2.6
Sistem Kanban ................................................................................... 17
2.3
Pemodelan Sistem .............................................................................. 19
2.3.1
Pendekatan Sistem ............................................................................. 19
2.3.2
Karakteristik dan Definisi Sistem ...................................................... 20
2.3.3
Model....................... .......................................................................... 21
2.3.3.1 Definisi Model ................................................................................ 21 2.3.3.2 Karakteristik Model . .................................................................... 21 2.4
Simulasi Sistem .................................................................................. 22
2.5
Simulasi Dengan ProModel 0.7 ......................................................... 26
2.5.1
Pengantar ProModel........................................................................... 26
2.5.2
STAT-FIT ......................................................................................... 26
2.5.3
Menu Build ProModel....................................................................... 27
2.6
Model awal System Junbiki ............................................................... 28
2.7
Model Eksperiment Sistem Junbiki ................................................... 30
2.8
Perhitungan Tack Time ...................................................................... 30
2.9
Perhitungan Waktu Siklus (Cycle Time) ........................................... 32
2.10
Perhitungan Man Power ..................................................................... 33 xvi
2.11
Analisa Model Terbaik ...................................................................... 34
BAB III METODOLOGI PENELITIAN. .................................................... 35 3.1
Pendahuluan .......................................................................................35
3.2
Studi Pustaka......................................................................................36
3.3
Penentuan Obyek Penelitian ..............................................................36
3.3.1
Lokasi Penelitian ................................................................................36
3.2.2
Waktu Penelitian ................................................................................37
3.4
Pembangunan Model .........................................................................37
3.4.1
Perhitungan Metode Junbiki Berdasarkan Tack Time .......................37
3.4.1.1 Tack Time ......................................................................................... 37 3.4.1.2 Lead Time Proses ............................................................................. 37 3.4.1.3 Unit Pemasukan Bahan Baku........................................................... 37 3.4.1.4 Data Lot Size .................................................................................... 37 3.4.1.5 Data Waktu Informasi ...................................................................... 37 3.4.1.6 Selisih Waktu Proses - Waktu Informasi ......................................... 38 3.4.1.7 Interval Kedatangan Truk ................................................................ 38 3.4.1.8 Kebutuhan Truk ............................................................................... 38 3.4.2
Perhitungan Metode Junbiki Berdasarkan Cycle Time ......................38
3.4.2.1 Cycle Time ....................................................................................... 38 3.4.2.2 Unit Pemasukan Bahan Baku........................................................... 38 3.4.3
Kebutuhan Man Power ......................................................................38
3.4.4
Perbandingan Perfoma Tack Time - Cycle Time ................................38
3.4.5
Mengganti Peran Inventori Dengan Sub – kontrak ............................38
3.4.6
Pengolahan Simulasi Inventori dan Sub kontrak ...............................39
3.4.6.1 Pembangun Model Awal.................................................................. 39 xvii
3.4.6.2 Verivikasi Model .............................................................................. 39 3.4.6.3 Validasi Model ................................................................................. 40 3.4.6.4 Standart Error .................................................................................. 40 3.5
Notasi………………………………… .............................................40
3.6
Identifikasi dan Perumusan Masalah ................................................41
3.7
Pengumpulan Data .............................................................................41
3.8
Pengolahan Data dan Analisis Hasil .................................................42
3.9
Hasil Penelitian ..................................................................................43
BAB IV PENGUMPULAN DAN PENGOLAHAN DATA ......................... 44 4.1
Data Instansi...................................................................................... 44
4.1.1
Gambaran Umum Instansi ................................................................ 44
4.1.2
Study Kasus Perusahaan .................................................................... 48
4.1.3
Produk Casting ................................................................................... 50
4.1.4
Casting Division................................................................................. 50
4.1.5
Proses Produksi .................................................................................. 51
4.1.6
Struktur Organisasi Casting Division................................................. 54
4.2
Data Observasi ................................................................................... 55
4.2.1
Jam Kerja Tenaga Kerja..................................................................... 55
4.2.2
Alur Proses Produksi Block Cylinder................................................ 55
4.2.3
Data Waktu Informasi........................................................................ 56
4.2.4
Kebutuhan Bahan Baku..................................................................... 60
4.2.5
Jumlah Tenaga Kerja......................................................................... 61
4.2.6
Data Untuk Pencarian Distribusi....................................................... 62
4.3
Pengolahan Data .................................................................... ........... 64
4.3.1
Permintaan Produk ............................................................................. 64 xviii
4.3.2
Perhitungan Metode Junbiki Berdasarkan Tack Time........................ 65
4.3.3
Perhitungan Metode Junbiki Berdasarkan Cycle Time...................... 69
4.3.4
Perbandingan Performa Tack Time dengan Cycle Time..................... 72
4.3.5
Uji Distribusi...................................................................................... 73
4.3.6
Membangun Model Awal Proses................................................. ..... 76
4.3.7
Hasil Simulasi Awal.......................................................................... 77
4.3.8
Verifikasi dan Validasi Model........................................................... 79
4.3.9
Pembangunan Model Alternatif......................................................... 80
4.3.10 Hasil Simulasi.................................................................................... 81 4.3.11 Pemilihan Model Alternatif............................................................... 83 BAB V PEMBAHASAN............................................................................... 89 5.1
Perhitungan Metode Junbiki Berdasarkan Tack Time ....................... 89
5.2
Perhitungan Metode Junbiki Berdasarkan Cycle Time ..................... 90
5.3
Kebutuhan Man Power Junbiki Berdasrkan Tack Time .................... 91
5.4
Kebutuhan Man Power Junbiki Berdasarkan Cycle Time ................. 91
5.5
Analisa Model Alternatif dengan Inventory ...................................... 92
5.6
Analisa Model Alternatif dengan Subcontract ................................... 93
BAB VI KESIMPULAN DAN SARAN ............... ...................................... 94 6.1
Kesimpulan................... ..................................................................... 94
6.2
Saran 95
DAFTAR PUSTAKA LAMPIRAN
xix
DAFTAR TABEL
Tabel 4.1 Profile PT.TOYOTA................................................................................ 46 Tabel 4.2 Jumlah Bahan Baku Logam Baja.............................................................
62
Tabel 4.3 Pemakaian Inventori per Hari ………………………………………….
63
Tabel 4.4 Data Hasil Produksi…………………………………………………….
65
Tabel 4.5 Data Hasil Simulasi Awal ………………............................................... 77 Tabel 4.6 Data Out put hasil simulasi model alternatif 1..……………................... 81 Tabel 4.7 Data Out put hasil simulasi model alternatif 2........................................ 82 Tabel 4.8 Analisa Model Alternatif dengan Inventori ……………………………
83
Tabel 4.9 Standart Error Inventori...........................................................................
84
Tabel 4.10 Analisa Model Alternatif dengan Sub kontrak......................................
86
Tabel 4.11 Standart Error Sub kontrak....................................................................
86
xx
DAFTAR GAMBAR
Gambar 2.1 Ilustrasi Junbiki.......................................................................................
7
Gambar 2.2 Sistem Produksi Just In Time (JIT)........................................................
15
Gambar 2.3 Diagram Alir Syarat-Syarat Penerapan JIT............................................ 16 Gambar 2.4 Model Manufaktur..................................................................................
29
Gambar 2.5 Model Grup Bisnis ………………………………….............................
29
Gambar 3.1
35
Diagram Alir Kerangka Penelitian......................................................
Gambar 4.1 Block Cylinder tipe TR............................................................................ 50 Gambar 4.2 Alur Proses Produksi Block Cylinder......................................................
55
Gambar 4.3 Dis.Johnson SB (156, -0.192, 0.399).....................................................
74
Gambar 4.4 Grafik .Johnson SB (156, -0.192, 0.399)……………………………....
74
Gambar 4.5 Autofit .Johnson SB (156, -0.192, 0.399)............................................... 75 Gambar 4.6 Dis.Triangular (58., 62.3, 61)..................................................................
75
Gambar 4.7 Grafik.Triangular (58., 62.3, 61)............................................................. 76 Gambar 4.8 Autofit Triangular (58., 62.3, 61)............................................................ 76 Gambar 4.9 model awal TOYOTA CASTING ……………………………..............
xxi
77
