Sains Malaysiana 42(12)(2013): 1787–1791
Thermoplastic Natural Rubber (TPNR) As a Backbone Polymer for Metal
Injection Molding
( Getah Asli Termoplastik(TPNR)
Sebagai Polimer Asas Untuk Pengacuanan
Suntikan Logam)
NORITA HASSAN12*, SAHRIM AHMAD1,NORHAMIDI MUHAMAD3, MOHD AFIAN OMAR4& NOOR AZLINA HASSAN2
1School of Applied Physic, Faculty of Science & Technology, Universiti Kebangsaan Malaysia
43600 Bangi, Selangor, Malaysia
2Department of Manufacturing and Materials Engineering, Faculty of
Engineering
International Islamic University Malaysia, P.O.Box
10, 50728 Kuala Lumpur, Malaysia
3Department of Mechanical and Material Engineering, Faculty of Engineering
Universiti Kebangsaan Malaysia, 43600 Bangi,
Selangor, Malaysia
4Advance Material Research
Centre (AMREC), SIRIM Berhad, Lot 34, Jalan Hi-Tech 2/3,
Kulim Hi-Tech Park, 09000 Kulim, Kedah,
Malaysia
Diserahkan: 23 Mac 2012/Diterima:
28 Mei 2012
ABSTRACT
Moldability of metal injection molding (MIM) is dependent on the
outward appearance of the resultant feedstock. Properties of the binders used
will influence the properties of the feedstock. Stainless steel powder 316L
with mean size 22 μm and the binder system
consists of three major fractions of paraffin wax, thermoplastic natural rubber
and stearic acid with a powder loading of 65 vol. % was investigated. Comparison
was also made with existing palm stearin in the binder system replacing the
paraffin wax. Kinetic solvent extractions were done to determine the
differences between the binder systems. The feedstock was then injected into
tensile bar using vertical injection machine. The results showed that there is
a slightly time extension during the solvent extraction as a comparison. The
feedstock has been successfully injection molded at 190-200°C. Study of thermal
analysis such as DSC and TGA has been done as a preparation for the
thermal debinding and sintering process. This study
demonstrated that a backbone polymer; thermoplastic natural rubber performs
best in term of flow stability and compact quality and also saves in processing
time.
Keywords: Backbone polymer; metal injection molding (MIM); thermal analysis;
thermoplastic natural rubber
ABSTRAK
Kebolehan pengacuan
suntikan logam
(MIM)
amat bergantung
kepada sifat bahan
suapan yang dihasilkan. Sifat bahan pengikat yang digunakan akan mempengaruhi sifat bahan suapan. Serbuk
keluli tahan
karat 316L dengan purata saiz
22 μm dan
sistem bahan pengikat
yang terdiri daripada
tiga bahagian utama
iaitu lilin
parafin,getah asli termoplastik
dan stearik
asid dengan bebanan serbuk logam 65% telah pun dikaji. Pembandingan
turut dilakukan dengan kehadiran stearin sawit dalam sistem
bahan pengikat
menggantikan lilin parafin. Pengekstrakan kinetik larutan
dilakukan untuk
menentukan perbezaan antara sistem-sistem bahan pengikat tersebut. Bahan suapan kemudian
disuntik kepada
bentuk bar regangan menggunakan mesin suntikan tegak. Keputusan
menunjukkan terdapat perbezaan masa semasa pengekstrakan larutan dilakukan sebagai satu perbandingan.
Bahan suapan
telah berjaya disuntik
pada 190-200°C. Analisis
terma iaitu DSC dan
TGA telah dilakukan sebagai persediaan untuk penyahikatan terma dan proses pensinteran. Kajian ini telah
membuktikan bahawa bahan pengikat iaitu asas (tulang
belakang) getah asli termoplastik
menunjukkan potensi
yang baik daripada segi kestabilan
aliran dan
kualiti padatan dan menjimatkan masa pemprosesan.
Kata kunci: Analisis terma; getah asli termoplastik
; pengacuan suntikan logam (MIM); polimer asas
RUJUKAN
Fan, Y-L., Hwang, K-S., Wu, S-H. & Liau, Y-C. 2009. Minimum amount of binder removal required
during solvent debinding of powder-injection-molded
compacts. Metallurgical and Materials Transactions A 40(4): 768-779.
German, R.M. & Bose, A.1997. Injection
Molding of Metals and Ceramics. New Jersey, USA: Metal Powder
Industries Federation, Princeton.
Huang, M-S. & Hsu, H-C. 2009. Effect of backbone polymer on
properties of 316L stainless steel MIM compact. Journal of Materials
Processing Technology 209(15-16): 5527-5535.
Kryachek, V.M.
2004. Injection moulding (Review). Powder Metallurgy and Metal Ceramics 43(7): 336-348.
Li, Y., Li, L. & Khalil, K.A. 2007. Effect of powder loading on metal injection
molding stainless steels. Journal of Materials Processing Technology 183(2-3):
432-439.
*Pengarang untuk surat-menyurat; email: norita.hassan08@gmail.com
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