TUGAS AKHIR ANALISA PENGARUH BENTUK SALURAN PENDINGIN Analisa Pengaruh Bentuk Saluran Pendingin Terhadap Cacat Warpage dari Produk Injeksi Plastik Berbahan Polypropylene.

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

xviii

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)

xxv

APPENDIX LIST

Appendix 1. Mould Design
Appendix 2. Cooling Design
Appendix 3. Image Measurement Result Area Warpage

xxvi