TUGAS AKHIR ANALISA PENGARUH BENTUK SALURAN PENDINGIN TERHADAP CACAT WARPAGE DARI PRODUK INJEKSI PLASTIK BERBAHAN POLYPROPYLENE
Disusun Sebagai Syarat Untuk Mencapai Gelar Sarjana Teknik Jurusan Teknik Mesin Fakultas Teknik Universitas Muhammadiyah Surakarta
Disusun Oleh : PRIYANTO D200 100 066
JURUSAN TEKNIK MESIN FAKULTAS TEKNIK UNIVERSITAS MUHAMMADIYAH SURAKARTA NOVEMBER 2015
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MOTTO
" Orang yang tidak pernah melakukan kesalahan adalah mereka yang tidak pernah mencoba hal-hal baru " (Albert Einstein) “Pendidikan merupakan perlengkapan paling baik untuk hari tua” (Aristoteles) "Musuh yang paling berbahaya di atas dunia ini adalah penakut dan bimbang. Teman yang paling setia, hanyalah keberanian dan keyakinan yang teguh" (Andrew Jackson)
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ABSTRAKSI Injection moulding adalah proses pembentukan plastik dengan cara melelehkan material plastik yang diinjeksikan ke dalam sebuah cetakan ( mould ). Cacat yang sering terjadi pada produk injection molding antara lain short shot (cacat produk kurang penuh), Sink mark(cacat titik seperti cekung pada produk) flash (cacat kelebihan bahan pada pinggir produk) dan warpage (cacat lengkungan pada produk). Faktor penyebab terjadinya warpage dipengaruhi oleh tekanan injeksi, suhu cetakan, titik leleh dan waktu tahan pada proses injeksi (Huang dan Tai, 2001). Oleh karena itu, tujuan dari penelitian ini adalah untuk meneliti pengaruh bentuk saluran pendingin terhadap cacat warpage dari hasil produk injection molding dan untuk menentukan bentuk saluran pendingin yang tepat sehingga didapatkan produk yang optimal dari injection molding. Langkah awal pembuatan cetakan (mould) dengan mesin CNC milling dan pembuatan pendingin dengan sistem soft tooling tipe saluran pendingin conformal dan tipe pendingin saluran lurus. Sistem sooftoling dibuat dengan mencampurkan serbuk aluminium dan lem epoxy dengan perbandingan 2:1 saluran conformal dicetak didalamnya. Metode pengambilan data luasan yang digunakan adalah pemrosesan gambar dengan pengambilan gambar menggunakan kamera 14 pixel dan diproses menggunakan software solidwork sehingga dapat dianalisa secara statistik dan untuk pengukuran cup(titik lengkung tertinggi) digunakan dial indikator, setelah didapat hasil, niali warpage dapat diketahui dengan (cup:diameter=warpage) kemudian dapat diambil sebuah kesimpulan. Dari hasil penelitian didapat kesimpulan bahwa dalam penelitian ini secara umum area warpage paling besar terjadi pada bentuk saluran pendinginan lurus dengan rata-rata sebesar 5724,71mm dan area warpage paling kecil untuk bentuk saluran peninginan conformal dengan rata-rata sebesar 4427,49mm. Sedangkan untuk nilai warpage yang paling besar terjadi pada bentuk saluran pendingin conformal yaitu dengan rata-rata sebesar 0,0452 dan nilai warpage paling kecil terjadi pada bentuk saluran pendinginan lurus yaitu dengan rata-rata sebesar 0,0375. Kata Kunci: injection molding, solidwork, dial indikator, bentuk saluran pendingin, warpage.
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ABSTRAKSI Injection molding is a plastic forming process by way of melting the plastic material is injected into a mold (mold). Defects that often occur in injection molding products include a short shot (defective products less full), Sink mark (point defects such as concave on the product) flash (excess material defect at the edge of the product) and warpage (arch defects in the product). The causes of warpage is affected by the injection pressure, mold temperature, melting and holding time in the injection process (Huang and Tai, 2001). Therefore, the aim of this study was to investigate the effect of the defective form of cooling channels warpage of the results of injection molding products and to determine the exact shape of the cooling channels to obtain the optimal product of injection molding. The initial step of making the mold (mold) with a CNC milling machine and manufacturing of coolers with soft tooling system type of conformal cooling channels and cooling type straight line. Sooftoling system is made by mixing powdered aluminum and epoxy glue in the ratio 2: 1 channel conformal printed therein. The data collection method extents used image processing with image capture using the camera 14 pixel and processed using software solidwork so it can be analyzed statistically and for measuring cup (point arch top) used a dial indicator, after we got the result, niali warpage can be determined by (cup : diameter = warpage) can then be drawn to a conclusion. From the results of the study concluded that in this study the general area of greatest warpage occurs in the form of a straight cooling channel with an average of 5724,71mm and warpage smallest area to form conformal cooling channel with an average of 4427,49mm. As for the value that most large warpage occurs in the form of the conformal cooling channels, namely with an average of 0.0452 and the smallest value of warpage occurs in the form of straight cooling channel that is with an average of 0.0375. Keywords: injection molding, solidwork, dial indicator, coolant channels form, warpage
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KATA PENGANTAR
Bismillahirrahmannirrahim Segala puji bagi Allah SWT yang telah memberikan rahmat, hidayah serta inayahnya sehingga tugas akhir berjudul “ANALISA PENGARUH BENTUK SALURAN PENDINGIN TERHADAP CACAT WARPAGE DARI PRODUK INJEKSI PLASTIK BERBAHAN POLYPROPYLENE”, dapat terselesaikan dengan baik. Penulisan tugas akhir ini merupakan salah satu syarat untuk menyelesaikan pendidikan Sarjana Strata Satu Teknik Mesin Universitas Muhammadiyah Surakarta. Tersusunya tugas akhir ini tidak lepas dari bantuan berbagai pihak, baik langsung maupun tidak langsung, untuk itu ucapan terima kasih kepada: 1. Bapak Ir. H. Sri Sunarjono, MT., Ph.D selaku dekan Fakultas Teknik Universitas Muhammadiyah Surakarta. 2. Bapak H. Tri Widodo Besar R., ST., Msc., Ph.D selaku Ketua Jurusan Teknik Mesin Fakultas Teknik Universitas Muhammadiyah Surakarta. 3. Bapak Bambang Waluyo F.,ST., MT selaku pembimbing I yang senantiasa memberikan koreksi dan bimbingannya. 4. Bapak Ir. Pramuko IP., MT selaku pembimbing II, terima kasih atas segala bimbingan dan masukannya. 5. Bapak Amin Sulistianto ST selaku pembimbing akademik yang telah memberikan nasehatnya selama ini. 6. Bapak
dan
Ibu
dosen
pengajar
Teknik
Mesin
Universitas
Muhammadiyah Surakarta yang telah memberikan ilmu perkuliahan kepada penulis. 7. Orang tua serta keluarga yang telah memberikan bantuan moral maupun materil yang tidak akan tergantikan.
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8. Rekan-rekan Teknik Mesin seperjuangan angkatan 2010 yang telah memberikan dukungan serta bantuan dikala susah dan senang. 9. Sahabat satu kelompok penelitian ( Priyanto, Joko, Zuli ) terima kasih atas kerjasama serta bantuannya selama ini. 10. Dan terakhir kepada seluruh pihak yang telah membantu dalam pembuatan Tugas Akhir ini. Penulis menyadari bahwa Laporan Tugas Akhir ini masih sangat jauh dari sempurna, maka dari itu penulis sangat mengharapkan saran dan kritik yang bersifat membangun, agar penulis dapat mengetahui dimana saja kekurangan laporan ini. Semoga laporan Tugas Akhir ini dapat berguna serta bermanfaat khususnya bagi penulis dan bagi pembaca pada umumnya.
Surakarta,
November 2015
Penulis
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DAFTAR ISI HALAMAN JUDUL ................................................................................. . i PERNYATAAN KEASLIAN SKRIPSI..................................................... . ii HALAMAN PERSETUJUAN .................................................................. iii HALAMAN PENGESAHAN ................................................................... iv LEMBAR SOAL TUGAS AKHIR ............................................................ v MOTTO ................................................................................................................ .vi ABSTRAK .............................................................................................. viii KATA PENGANTAR .............................................................................. ix DAFTAR ISI ........................................................................................... xi DAFTAR GAMBAR .................................................................................xiv DAFTAR TABEL .................................................................................. .xvi DAFTAR LAMPIRAN ........................................................................... xviii BAB I PENDAHULUAN 1.1. Latar Belakang ........................................................................ 1 1.2. Perumusan Masalah ................................................................ 3 1.3. Pembatasan masalah .............................................................. 3 1.4. Tujuan Penelitian ..................................................................... 4 1.5. Manfaat penelitian ................................................................... 4 1.6. Metode Penulisan .................................................................... 4 1.7. Sistematika penulisan.................................................................5
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BAB II TINJAUAN PUSTAKA 2.1. Kajian Pustaka ........................................................................ 7 2.2. Landasan Teori ....................................................................... 8 2.2.1. Plastik .............................................................................. 8 2.2.2. Polypropylene .................................................................. 9 2.2.3. Proses Pembentukan Polimer .......................................... 12 2.2.4. Injection Molding .............................................................. 13 2.2.5. Kontruksi Mesin Injection Moulding .................................. 15 2.2.6. Sistem Pendingin pendinginan ......................................... 20 2.2.7. Cacat Produk Injection Molding ........................................ 21 2.2.8. Cacat Warpage ................................................................ 23 2.2.9. Perpindahan panas.............................................................25 BAB III METODOLOGI PENELITIAN 3.1. Diagram Alir Penelitian ............................................................ 28 3.2. Penguraian diagram alir.............................................................29 3.3. Data proses injeksi plastik ........................................................29 3.4. Tempat penelitian lapangan .................................................... 22 3.5. Proses Pembuatan Cetakan .................................................... 30 3.6. Bahan yang digunakan dalam pembuatan spesimen............... 36 3.6.1. Polypropylene. ............................................................... 36 3.7. Mesin injeksi molulding ............................................................ 36
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3.8. Peralatan pendukung .............................................................. 37 3.9. Prosedur pembuatan produk ................................................... 42 3.10. Sampel .................................................................................. 43 3.11. Rancangan analisa data ........................................................ 44 3.12. Kesulitan ............................................................................... 44 BAB IV HASIL DAN ANALISA PENELITIAN 4.1. Data hasil penelitian ............................................................... 45 4.1.1. Analisa saluran pendingin .............................................. 46 4.1.2. Data waktu siklus percobaan .......................................... 46 4.1.3. Cacat area warpage ....................................................... 47 4.1.4. Pengukuran nilai warpage .............................................. 51 4.1. Cacat-cacat saat proses pembuatan spesimen ...................... 53 4.2.1. Produk burning ............................................................... 51 4.2.2. Cacat short shot ............................................................. 54 4.2.3. Cacat flash ..................................................................... 55 4.2.4. Cacat silver streak .......................................................... 56 BAB V KESIMPULAN DAN SARAN 5.1. Kesimpulan.............................................................................. 57 5.2. Saran....................................................................................... 57 DAFTAR PUSTAKA LAMPIRAN
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DAFTAR GAMBAR
Gambar 2.1. Biji Plastik Polypropylene ................................................... 9 Gambar 2.2. Bagian Mesin Injeksi Plastik Horizontal .............................. 14 Gambar 2.3. Bagian Mesin Injeksi Plastik Vertikal .................................. 15 Gambar 2.4.Bagian-bagian Injection Unit .............................................. 16 Gambar 2.5. Skematik dan Bagian-bagian dari Clamping Unit ............... 17 Gambar 2.6. Bagian Utama dari Mold Unit ............................................. 18 Gambar 2.7. Sistem Pendingin Konvensional ......................................... 20 Gambar 2.8. Sistem Pendingin Konformal .............................................. 21 Gambar 2.9. Warpage karena Ketidak-seragaman Dinding Ketebalan .......................................................................... 23 Gambar 2.10. Skema Perhitungan Warpage .......................................... 24 Gambar 2.11. Rumus Empiris Aliran pada Tabung ................................. 26 Gambar 3.1. Diagram Aliran Penelitian ................................................... 28 Gambar 3.2. Bentuk Spesimen yang direncanakan ................................ 31 Gambar 3.3. Desain Mould ..................................................................... 31 Gambar 3.4. Desain Saluran Pendingin Conformal ................................ 32 Gambar 3.5. Desain Saluran Pendingin Lurus ....................................... 32 Gambar 3.6. Kompponen Mould ............................................................. 34 Gambar 3.7. Bahan Pembuat Pendingin ................................................. 37
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Gambar 3.8. Proses Pembuatan Pendingin ............................................ 36 Gambar 3.9. Polipropylene ..................................................................... 36 Gambar 3.10. Instalasi Mesin Injeksi Plastik ........................................... 37 Gambar 3.11. Thermometer ................................................................... 38 Gambar 3.12. Stopwatch ........................................................................ 38 Gambar 3.13. Kunci Pas ......................................................................... 39 Gambar 3.14. Gerinda ............................................................................ 39 Gambar 3.15. Gelas Ukur ....................................................................... 40 Gambar 3.16. Pompa Air ........................................................................ 40 Gambar 3.17. Selang Air ........................................................................ 41 Gambar 3.18. Ember .............................................................................. 41 Gambar 3.19. Dial Indikator .................................................................... 41 Gambar 3.20. Prosedur Pembuatan Produk ........................................... 42 Gambar 3.21. Spesimen ......................................................................... 43
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DAFTAR TABEL
Tabel 2.1. Sifat Fisik, Mekanis dan Termal dari Polypropylene...............11 Tabel 2.2. Sifat-sifat Cairan Jenuh .......................................................... 27 Tabel 3.1. Data Kondisi Proses Injeksi Plastik ........................................ 30 Tabel 4.1. Data Kondisi Injeksi Plastik pada Pendingin Conformal ......... 45 Tabel 4.2. Data Kondisi Injeksi Plastik pada Pendingin Lurus ................. 45 Tabel 4.3. Data Hasil Pengukuran Warpage Saluran Conformal............. 47 Tabel 4.4. Data Hasil Pengukuran Warpage Saluran Lurus .................... 48 Tabel 4.5. Data Hasil Pengukuran Niai Warpage .................................... 51
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DAFTAR SIMBOL hpart = Ketinggian warpage
(mm)
dpart
= Diameter Spesimen
(mm)
q
= Laju perpindahan panas
A
= Luas penampang dimana panas mengalir
(m2)
k
= Konduktivitas thermal bahan
(w/moC)
m
= laju aliran fluida
Cp
= Panas jenis
(kj/kg.0C)
Tb
= Suhu limbak
(Cº)
Tw
= Suhu dinding
(Cº)
Um
= Kec. Rata-rata
(m/s)
Μ
= Kekentalan
(kg/m.s)
ρ
= Kerapatan
(kg/m3)
(w)
(kg/s)
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DAFTAR LAMPIRAN Lampiran 1. Desain Mould Lampiran 2. Desain Pendingin Lampiran 3. Gambar Hasil Pengukuran Area Warpage
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TABLE OF CONTENTS
TITLE PAGE .......................................................................................... . i STATEMENT OF AUTHENTICITY Thesis ............................................. . ii APPROVAL PAGE ................................................................................. iii PAGE ENDORSEMENT ......................................................................... iv PROBLEM SHEET FINAL ..................................................................... v MOTTO ............................................................................................................... .vi ABSTRACT ............................................................................................ vii FOREWORD .......................................................................................... vii CONTENTS ............................................................................................ x LIST OF FIGURES ................................................................................. xiii LIST OF TABLES................................................................................. .xvi APPENDIX LIST................................................................................... .xvii CHAPTER I INTRODUCTION 1.1. Background ............................................................................. 1 1.2. Problem Formulation................................................................ 3 1.3. Restrictions issue ..................................................................... 3 1.4. Objective.................................................................................. 4 1.5. Benefits Research ................................................................... 4 1.6. Writing Method......................................................................... 4 1.7. Writing system.................................................................5
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CHAPTER II LITERATURE 2.1. Studies Reader ........................................................................ 7 2.2 Basis Theory. ............................................................................ 8 2.2.1. Plastic ............................................................................... 8 2.2.2. Polypropylene .................................................................. 9 2.2.3. Polymer Formation Process .............................................. 12 2.2.4. Injection Molding .............................................................. 13 2.2.5. Construction Machinery Injection Moulding ....................... 15 2.2.6. Cooling System cooling .................................................... 20 2.2.7. Product Defect Injection Molding ...................................... 21 2.2.8. Disability Warpage ............................................................ 23 2.2.9. Heat transfer ……..............................................................25 CHAPTER III RESEARCH METHODOLOGY 3.1. Research Flow Chart ............................................................... 28 3.2. Unraveling a flowchart................................................................29 3.3.Data plastic injection process.....................................................29 3.4. Points 22 field research ........................................................... 22 3.5. Mold Making Process............................................................... 30 3.6. The materials used in the manufacture of the specimen .......... 36 3.6.1. Polypropylene. ............................................................... 36 3.7. Molulding injection machines ................................................... 36
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3.8. Support equipment .................................................................. 37 3.9. The procedure of making products .......................................... 42 3.10. Sampel .................................................................................. 43 3.11. The design of data analysis ................................................... 44 3.12. Difficulty ................................................................................. 44 CHAPTER IV RESULTS AND ANALYSIS RESEARCH 4.1. Data from the study ................................................................. 45 4.1.1. Analysis of the cooling channel ....................................... 46 4.1.2. Data cycle time trial ........................................................ 46 4.1.3. Defect area warpage ...................................................... 47 4.1.4. Measurement of the value of warpage. ........................... 51 4.1. Defects during the manufacturing process the specimen ......... 53 4.2.1. Product burning .............................................................. 51 4.2.2. Defects short shot ........................................................... 54 4.2.3. Disability flash ................................................................ 55 4.2.4. Disability silver streak ..................................................... 56 CHAPTER V CONCLUSIONS AND SUGGESTIONS 5.1. Conclusion .............................................................................. 57 5.2. Suggestions ............................................................................. 57 BIBLIOGRAPHY ATTACHMENT
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LIST OF FIGURES
Figure 2.1. Seeds Polypropylene Plastics….. ....................................... 9 Figure 2.2. Horizontal Plastic Injection Machine Part .............................. 14 Figure 2.3. Vertical Plastic Injection Machine Part .................................. 15 Figure 2.4.Bagian-part Injection Unit ....................................................... 16 Figure 2.5. Schematic and portions of the Clamping Unit ....................... 17 Figure 2.6. Main part of Mold Unit ........................................................... 18 Figure 2.7. Conventional Cooling System ............................................... 20 Figure 2.8. Conformal Cooling System ................................................... 21 Figure 2.9. Warpage due to lack uniformities Wall thickness ................................................................................................ 23 Figure 2.10. Warpage Calculation Scheme ............................................. 24 Figure 2.11. Empirical formula Flow in Tubes ......................................... 26 Figure 3.1. Flow Diagram Research ....................................................... 28 Figure 3.2. Specimen form of the planned .............................................. 31 Figure 3.3. Mould Design ........................................................................ 31 Figure 3.4. Conformal Cooling Channel Design ...................................... 32 Figure 3.5. Cooling Channel Design Straight .......................................... 32 Figure 3.6. Kompponen Mould ................................................................ 34 Figure 3.7. Material Makers Cooling ....................................................... 37
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Figure 3.8. Process Cooling .................................................................... 36 Figure 3.9. Polipropylene ........................................................................ 36 Figure 3.10. Plastic Injection Machinery Installation ................................ 37 Figure 3.11. thermometer ....................................................................... 38 Figure 3.12. Stopwatch ........................................................................... 38 Figure 3.13. Pas Lock ............................................................................. 39 Figure 3.14. Burrs ................................................................................... 39 Figure 3.15. Glass Measure .................................................................... 40 Figure 3.16. Pump .................................................................................. 40 Figure 3.17. Air Hose .............................................................................. 41 Figure 3.18. Ember ................................................................................. 41 Figure 3.19. Dial Indicators ..................................................................... 41 Figure 3.20. Product Creation Procedure ................................................ 42 Figure 3.21. specimen ............................................................................ 43
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LIST OF TABLES Table 2.1. Physical Properties, Mechanical and Thermal Polypropylene..11 Table 2.2. Properties of Saturated Fluids ................................................ 27 Table 3.1. Plastic Injection Process Condition Data ................................ 30 Table 4.1. Plastic Injection Condition Data on Conformal Cooling........... 45 Table 4.2. Plastic Injection Condition Data on Cooling Straight ............... 45 Table 4.3. Warpage Measurement Result Data Channel Conformal ....... 47 Table 4.4. Warpage Measurement Result Data Channel Straight ........... 48 Table 4.4. Warpage Measurement Result Data Channel Straight ........... 51
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LIST OF SYMBOLS hpart = Height
(mm)
dpart
= Diameter
(mm)
q
= Heat Transfer Rate
(w)
A
= Cross-Sectional Area in Which Heat Flow
(m2)
k
= Thermal Conductivity of the Material
m
= Fluid Flow Rate
Cp
= Specific Heat
Tb
= Temperature Modulus
(Cº)
Tw
= Wall Temperature
(Cº)
Um
= District. Average
Μ
= Viscosity
(kg/m.s)
ρ
= Density
(kg/m3)
(w/moC) (kg/s) (kj/kg.0C)
(m/s)
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APPENDIX LIST
Appendix 1. Mould Design Appendix 2. Cooling Design Appendix 3. Image Measurement Result Area Warpage
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