perencanaan kebutuhan bahan baku...
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PERENCANAAN KEBUTUHAN BAHAN BAKU RAKET
(Study Kasus : CV. Abadi)
Skripsi
Diajukan Kepada Universitas Muhammadiyah Malang
Untuk Memenuhi Salah Satu Persyaratan Akademik
Dalam Menyelesaikan Program Sarjana Teknik
Disusun Oleh :
Moch Rif Brasky
08540054
JURUSAN TEKNIK INDUSTRI
FAKULTAS TEKNIK
UNIVERSITAS MUHAMMADIYAH MALANG
2014
LEMBAR PENGESAHAN SKIPSI
PERENCANAAN KEBUTUHAN BAHAN BAKU RAKET
(Study Kasus : CV. Abadi)
Disusun Oleh :
Moch Rif Brasky
08540054
Menyetujui dan Mengesahkan :
Malang,
Dosen Pembimbing I Dosen Pembimbing II
Annisa Kesy Garide, ST, MT Dr. Ilyas Masudin, ST, M.logSCM
Mengetahui,
Ketua Jurusan Teknik Industri
Dr. Ilyas Masudin, ST, M.logSCM
KATA PENGANTAR
Dengan nama Allah yang Maha Pengasih lagi Maha Penyayang, syukur Alhamdullillah
penulis panjatkan kehadirat Allah SWT, atas limpahan rahmat, kasih sayang, petunjuk, dan
karunia-Nya sehingga penulis dapat menyelesaikan penyusunan tugas akhir ini. Tugas akhir
ini disusun sebagai salah satu syarat untuk menyelesaikan studi dan memperoleh gelar sarjana
di Universitas Muhammadiyah Malang.
Selama proses penyusunan tugas akhir ini, penulis banyak mengalami kendala, akan
tetapi telah ada beberapa pihak yang turut membantu, untuk itu penulis mengucapkan terima
kasih kepada:
1. Yang saya hormati, Kedua orang tuaku Bapak Suyitno dan Ibu Naimah yang telah
sepenuh hati berdo’a untukku, memberi dukungan moril dan materiil, serta kasih
sayangnya.
2. Yang aku cintai dan sayangi Vanindya Crisyantya, tanpa lelah memberi dukungan, dan
selalu mencurahkan waktu untuk memotivasi selama pengerjaan tugas akhir ini.
3. Ibu Annisa Kesy G., ST, MT dan Bapak Dr. Ilyas Masudin, ST, M.logSCM selaku
dosen Pembimbing I dan II. Terima kasih telah meluangkan waktu untuk membimbing
saya dan tidak pernah memepersulit pengerjaan laporan ini.
4. Terima kasih kepada Bapak Kaeri Soemarno, selaku kepala perusahaan CV. Abadi.
Karena telah mengizinkan saya penelitian di perusahaan Bapak. Terima kasih juga
terhadap Mas Arif yang telah membimbing saya didalam perusahaan tersebut.
5. Dan untuk sahabat, teman, dan semua pihak yang tidak dapat saya sebutkan satu per
satu yang telah membantu terselesaikannya tigas akhir ini, saya ucapkan banyak terima
kasih.
Meskipun penulis telah mendapat bantuan dari semua pihak di atas, namun jika terdapat
kesalahan teknis dan nonteknis adalah sepenuhnya menjadi tanggung jawab penulis. Mudah –
mudahan Tugas Akhir ini dapat bermanfaat bagi para pembaca.
Penulis
DAFTAR ISI
Halaman Judul ...........................................................................................................
Lembar Pengesahan Skripsi .......................................................................................
Lembar Asistensi Skripsi ..........................................................................................
Berita Acara Ujian .....................................................................................................
Surat Pernyataan Keaslian .........................................................................................
Surat Keterangan Pengambilan Data dari Perusahaan ..............................................
Kata Pengantar .......................................................................................................... i
Abstraksi ................................................................................................................... ii
Abstract ..................................................................................................................... iii
Daftar Isi .................................................................................................................... iv
Daftar Tabel .............................................................................................................. viii
Daftar Gambar ........................................................................................................... xi
Lampiran ...................................................................................................................
BAB I PENDAHULUAN
1.1 Latar Belakang ................................................................................................... 1
1.2 Rumusan Masalah .............................................................................................. 2
1.3 Tujuan Penelitian ............................................................................................... 2
1.4 Manfaat Penelitian ............................................................................................. 3
1.5 Batasan Masalah ................................................................................................ 3
BAB II LANDASAN TEORI
2.1 Persediaan (Inventory) ....................................................................................... 4
2.1.1 Definisi Persediaan ................................................................................... 4
2.1.2 Fungsi Persediaan ..................................................................................... 5
2.1.3 Biaya – Biaya Persediaan .......................................................................... 6
2.1.4 Pengendalian Persediaan ........................................................................... 7
2.2 Peramalan (Forcast) ........................................................................................... 7
2.2.1 Definisi Peramalan .................................................................................... 7
2.2.2 Metode Peramlan ...................................................................................... 9
2.3 Rencana Agregat ................................................................................................ 13
2.3.1 Definisi Rencana Agregat ......................................................................... 13
2.3.2 Metode dalam Perencanaan Agregat ........................................................ 14
2.4 Jadwal Induk Produksi ....................................................................................... 15
2.5 Safety Stock ........................................................................................................ 16
2.6 Material Requirement Planning (MRP) ............................................................ 17
2.6.1 Definisi Sistem MRP ................................................................................ 17
2.6.2 Kemampuan Sistem MRP ......................................................................... 17
2.6.3 Karakteristik Dasar Sistem MRP .............................................................. 18
2.6.4 Input MRP ................................................................................................. 19
2.6.5 Output Sistem MRP .................................................................................. 21
2.6.6 Langkah-langkah Dasar Proses Pengolahan MRP .................................... 22
2.6.7 Lot Sizing (Ukuran Lot) ............................................................................ 25
2.6.8 Algoritma Silver-Meal (SM) ..................................................................... 27
BAB III METODOLOGI PENELITIAN
3.1 Survei Lapangan ................................................................................................ 30
3.2 Identifikasi Masalah ........................................................................................... 30
3.3 Studi Literatur .................................................................................................... 30
3.4 Penentuan Tujuan ............................................................................................... 31
3.5 Pengumpulan Data ............................................................................................. 31
3.6 Pengolahan Data ................................................................................................ 31
3.6.1 Peramalan .................................................................................................. 31
3.6.2 Perencanaan Agregasi ............................................................................... 32
3.6.3 Pembuatan Jadwal Induk Produksi ........................................................... 32
3.6.4 Pembuatan MRP ....................................................................................... 32
3.7 Perhitungan Ukuran Pemesanan ........................................................................ 33
3.8 Analisa Pembahasan .......................................................................................... 33
3.9 Kesimpulan dan Saran ....................................................................................... 33
3.10 Flowchart Penelitian ......................................................................................... 34
BAB IV PENGUMPULAN DAN PENGOLAHAN DATA
4.1 Tinjauan Umum Perusahaan .............................................................................. 35
4.1.1 Sejarah Pabrik ........................................................................................... 35
4.1.2 Tujuan Perusahaan .................................................................................... 36
4.2 Pemgumpulan Data ............................................................................................ 36
4.2.1 Data Raket Yang Diproduksi .................................................................... 36
4.2.2 Bill Of Material Raket .............................................................................. 37
4.2.3 Data Proses Produksi Raket ...................................................................... 39
4.2.4 Peta Proses Operasi ................................................................................... 40
4.2.5 Data Waktu Proses Tiap Unit Raket ......................................................... 41
4.2.6 Data Permintaan Raket ............................................................................. 41
4.2.7 Data Persediaan Akhir dan Lead Time Pemesanan ................................... 42
4.2.7.1 Data Persediaan Akhir .................................................................... 42
4.2.7.2 Lead Time Pemesanan ..................................................................... 43
4.2.8 Data Safety Stock dan Kalender Kerja ...................................................... 44
4.2.8.1 Data Safety Stock ............................................................................. 44
4.2.8.2 Data Kalender Kerja ....................................................................... 46
4.2.9 Data Biaya Pada Perusahaan ..................................................................... 46
4.2.9.1 Biaya Simpan .................................................................................. 46
4.2.9.2 Biaya Pesan ..................................................................................... 48
4.3 Pengolahan data ................................................................................................. 49
4.3.1 Pola Data ................................................................................................... 49
4.3.1.1 Pola Data Produk Raket .................................................................. 49
4.3.2 Peramalan dan Perhitungan MAPE .......................................................... 49
4.3.3 Pemilihan Metode Peramalan ................................................................... 57
4.3.4 Hasil Peramalan dengan Metode Terpilih ................................................. 58
4.3.5 Perencanaan Agregat Metode Chase Strategy dan Level Strategy ........... 58
4.3.5.1 Perencaan Agregat Metode Chase Strategy .................................... 58
4.3.5.2 Perencanaan Agregat Metode Level Strategy ................................. 60
4.3.6 Jadwal Induk Produksi (JIP) ..................................................................... 61
4.3.7 Material Requirement Planning (MRP) ................................................... 63
4.3.7.1 MRP dengan Metode Perusahaan ................................................... 63
4.3.7.2 MRP dengan Metode Usulan .......................................................... 69
4.3.7.3 Biaya yang dikeluarkan dengan Metode Perusahaan ...................... 71
4.3.7.4 Biaya yang Dikeluarkan dengan Metode Usulan ............................ 72
BAB V ANALISA PEMBAHASAN
5.1 Plotting Data ...................................................................................................... 74
5.2 Pemilihan Metode Peramalan ............................................................................ 74
5.3 Tracking Signal .................................................................................................. 75
5.4 Metode Agregasi ................................................................................................ 75
5.4.1 Metode Chase Strategy ............................................................................. 75
5.4.2 Metode Level Strategy .............................................................................. 75
5.5 Jadwal Induk Produksi ....................................................................................... 76
5.6 MRP Metode Perusahaan dengan Usulan .......................................................... 76
5.6.1 Metode Perusahaan ................................................................................... 76
5.6.2 Metode Usulan .......................................................................................... 77
5.7 Perbandingan Biaya Perencanaan MRP Metode Perusahaan dengan Usulan ... 79
5.7.1 Metode Perusahaan ................................................................................... 79
5.7.2 Metode Usulan .......................................................................................... 80
BAB VI KESIMPULAN
6.1 Kesimpulan ........................................................................................................ 82
6.2 Saran .................................................................................................................. 83
DAFTAR TABEL
Tabel 2.1 Permintaan Produksi-Inventori berdasarkan tiga metode .......................... 15
Tabel 2.2 Format MRP ............................................................................................... 22
Tabel 2.3 Perhitungan Total Variable Cost ............................................................... 29
Tabel 4.1 Jenis Produk Raket ..................................................................................... 37
Tabel 4.2 Data Bahan Baku Untuk 1 Raket Merek Sanyo ......................................... 38
Tabel 4.3 Data Bahan Baku Untuk 1 Raket Merek Istora.......................................... 38
Tabel 4.4 Data Bahan Baku Untuk 1 Raket Merek Prima ......................................... 39
Tabel 4.5 Waktu Proses Raket ................................................................................... 41
Tabel 4.6 Data Permintaan Raket (February 2012 - Januari 2014)............................ 41
Tabel 4.7 Persediaan akhir unit Raket........................................................................ 42
Tabel 4.8 Persediaan akhir Bahan Baku bulan Januari 2014 ..................................... 43
Tabel 4.9 Lead time bahan baku ................................................................................ 43
Tabel 4.10 Lot size Bahan baku ................................................................................. 44
Tabel 4.11 Lot size bahan Produk Raket .................................................................... 44
Tabel 4.12 Safety Stock Raket .................................................................................... 45
Tabel 4.13 Kalender kerja February - April 2014 ...................................................... 46
Tabel 4.14 Biaya Simpan Raket Sanyo ...................................................................... 47
Tabel 4.15 Biaya Simpan Raket Istora ....................................................................... 47
Tabel 4.16 Biaya Simpan Raket Prima ...................................................................... 48
Tabel 4.17 Data Biaya Pesan ..................................................................................... 48
Tabel 4.18 Biaya Reguler dan Overtime .................................................................... 48
Tabel 4.19 Perhitungan Berdasarkan Model SES (α = 1) ......................................... 50
Tabel 4.20 Tracking Signal dari Model Peramalan SES (α = 1) ............................... 52
Tabel 4.21 Hasil MAPE Berdasarkan Metode Peramalan Terpilih ........................... 57
Tabel 4.22 Hasil Peramalan Permintaan Produk Raket dengan HWA α = 0,8 (unit) 58
Tabel 4.23 Rencana Agregat dengan Metode Chase Strategy ................................... 59
Tabel 4.24 Rencana Agregat dengan Metode Level Strategy .................................... 60
Tabel 4.25 Rencana Produksi Agregat ....................................................................... 61
Tabel 4.26 Jadwal Induk Produksi ............................................................................. 62
Tabel 4.27 MRP Raket Sanyo ..................................................................................... 63
Tabel 4.28 MRP Raket Istora ...................................................................................... 64
Tabel 4.29 MRP Raket Prima ...................................................................................... 65
Tabel 4.30 MRP Sub Assembly Raket Sanyo .............................................................. 66
Tabel 4.31 MRP Frame Raket Sanyo ........................................................................... 67
Tabel 4.32 MRP Alumunium Raket Sanyo .................................................................. 67
Tabel 4.33 MRP Sub Assembly Shaft Raket Sanyo ...................................................... 67
Tabel 4.34 MRP Batang Baja Raket Sanyo .................................................................. 68
Tabel 4.35 MRP Baja Raket Sanyo ............................................................................. 68
Tabel 4.36 MRP Crop ................................................................................................. 68
Tabel 4.37 MRP Alumunium Sanyo .......................................................................... 69
Tabel 4.38 Perhitungan Silver Meal Alumunium Sanyo ........................................... 69
Tabel 4.39 Perhitungan Silver Meal Alumunium Sanyo ........................................... 70
Tabel 4.40 MRP Baja Sanyo ...................................................................................... 70
Tabel 4.41 Perhitungan Silver Meal Baja Sanyo ....................................................... 70
Tabel 4.42 Perhitungan Silver Meal Baja Sanyo ....................................................... 71
Tabel 4.43 Biaya Persediaan Alumunium .................................................................. 71
Tabel 4.44 Biaya Persediaan Baja .............................................................................. 72
Tabel 4.45 Biaya Persediaan Crop ............................................................................. 72
Tabel 4.46 Biaya Persediaan Alumunium .................................................................. 73
Tabel 4.47 Biaya Persediaan Baja .............................................................................. 73
Tabel 5.1 Tabel 5.1 Hasil MAPE Berdasarkan Metode Peramalan Terpilih ............. 74
Tabel 5.2 Tabel 5.2 Perbandingan biaya antara chase strategy dan level strategy .... 76
Tabel 5.3 Jadwal Induk Produksi ............................................................................... 76
Tabel 5.4 Periode Pemesanan Alumunium ................................................................ 77
Tabel 5.5 Periode Pemesanan Baja ............................................................................ 77
Tabel 5.6 Periode Pemesanan Crop ........................................................................... 77
Tabel 5.7 Periode Pemesanan Alumunium ................................................................ 78
Tabel 5.8 Periode Pemesanan Baja ............................................................................ 78
Tabel 5.9 Biaya Persediaan Alumunium .................................................................... 79
Tabel 5.10 Biaya Persediaan Baja .............................................................................. 79
Tabel 5.11 Biaya Persediaan Crop ............................................................................ 80
Tabel 5.12 Biaya Persediaan Alumunium .................................................................. 80
Tabel 5.13 Biaya Persediaan Baja .............................................................................. 81
Tabel 5.14 Perbandingan Total Biaya ....................................................................... 81
DAFTAR GAMBAR
Gambar 2.1 Struktur Produk ...................................................................................... 19
Gambar 2.2 Proses Kerja dari MRP .......................................................................... 21
Gambar 3.1 Flowchart Penelitian .............................................................................. 34
Gambar 4.1 Bill of Material Raket ............................................................................. 37
Gambar 4.2 OPC Raket .............................................................................................. 40
Gambar 4.3 Pola data permintaan Raket .................................................................... 49
Gambar 4.4 Peta Kontrol Model Single Exponential Smoothing (α = 1) ................... 53
Gambar 4.5 Peramalan SES (α = 1) Menggunakan software winQSB ...................... 54
Gambar 4.6 Peramalan HWA (α = 0,8) Menggunakan software winQSB ................. 56
Gambar 4.7 Peta Kontrol Model Holt-Winters Additive (α = 0,8) ............................. 57
DAFTAR PUSTAKA
Baroto, Teguh. 2002. Pengantar Teknik Industri, Malang : Universitas
Muhammadiyah Malang.
Buffa, Elwood S dan Sarin Rakesh K. 1996. Manajemen Operasi & Produksi
Modern, Jilid I (Edisi VIII), Jakarta : Binarupa Aksara.
Gaspersz, Vincent. 1998. Production Planning and Inventory Control, Jakarta :
Kerja sama Vincent Foundation dengan PT. Gramedia Pustaka Utama.
Makridakis, Spyros dan Steven C. Wheelwright. 1994. Metode-metode Peramalan
untuk Manajemen, Jakarta Barat : Binarupa Aksara.
Nasution, Arman Hakim. 2003. Perencanaan dan Pengendalian Produksi, Surabaya
: Teknik Industri ITS.
Ristono, Agus. 2009. Manajemen Persediaan . Yogyakarta : Graha Ilmu.
Yamit, Zulian. 2003. Manajemen Persediaan, Yogyakarta : Ekonisa.
Zulfikarijah, Fien. 2005. Manajemen Persediaan, Universitas Muhammadiyah
Malang.