Sains Malaysiana 46(3)(2017):
477–483
http://dx.doi.org/10.17576/jsm-2017-4603-16
Effect of Mixing Process Parameters and
Suitability of Backbone Polymer for Aluminum Powder Injection Molding Feedstock
(Kesan Parameter Proses Percampuran dan
Kesesuaian Polimer Tulang Belakang bagi Bahan Mentah Membentuk Suntikan Serbuk
Aluminium)
A.A. ABDULLAHI , I.A. CHOUDHURY*, M. AZUDDIN
& N. NAHAR
Manufacturing Systems
Integration, Department of Mechanical Engineering, University of Malaya
50603 Kuala Lumpur, Federal
Territory, Malaysia
Diserahkan: 22 Mei 2016/Diterima: 17 Ogos 2016
ABSTRACT
A suitable and cost-effective
microfabrication technique for processing aluminum micropart is required, as
the choice of aluminum microparts for aerospace, electronics and automobile
components is preferred over other metals due to its excellent properties.
Meanwhile, powder injection molding (PIM) is identified as an
economical manufacturing technique for processing ceramic and micro-metal
powders into microparts and or components. Therefore, this study investigates
formulation and processing of aluminum PIM feedstock using a
custom-made machine. The investigation is focused on the effect of mixing
process parameters (powder loading, rotor speed and mixing temperature) and the
suitability of the backbone polymer. The formulated PIM feedstock
constituents are paraffin wax (PW), stearic acid (SA),
high-density polyethylene (HDPE)/ medium-density polyethylene (MDPE)
alternatively and aluminum micro-metal powder. Taguchi method is used for the
design of experiments (DOEs) and analysis. In addition,
response surface methodology (RSM) is employed to develop
empirical viscosity models. The optimum powder-binder mixing ratio of 58:42
vol. % with rotor speed of 43 rpm were determined for preparing aluminum PIM feedstock
using mini-lab mixer developed. The empirical model developed for aluminum PIM feedstock
viscosity shows a good fit with R2 values of 0.84 using HDPE and 0.96 for MDPE binder system. This investigation
demonstrates preparation and suitability of aluminum PIM feedstock
using wax-based binder system.
Keywords: Aluminum; injection
molding; optimization; powder-binder mixing; viscosity
ABSTRAK
Teknik mikrofabrikasi yang sesuai
dan kos efektif dalam memproses komponen mikrobahagian
aluminum amat diperlukan kerana ciri yang dimiliki adalah sangat bagus dan
aluminum adalah pilihan yang lebih baik berbanding logam lain dalam pembuatan
komponen pada skala mikro dalam bidang aeroangkasa, elektronik dan juga
automotif. Sementara itu, sistem pengacuan logam teknik
suntikan serbuk (PIM) dikenal pasti sebagai teknik
pembuatan yang cekap daripada segi ekonomi untuk memproses serbuk seramik dan
logam kepada komponen berskala mikro. Oleh itu,
penyelidikan ini mengkaji formula dan teknik pemprosesan bahan mentah aluminum PIM menggunakan
mesin khas buatan sendiri. Kajian ini memberi tumpuan kepada kesan
campuran pelbagai proses parameter (bebanan serbuk, kelajuan rotor dan suhu
campuran) serta kesesuaian penggunaan tulang belakang polimer. Formula untuk
bahan mentah PIM yang digubal adalah lilin parafin (PW),
asid stearik (SA), polietilena berketumpatan tinggi (HDPE)/polietilena
berketumpatan sederhana (MDPE) sebagai alternatif dan serbuk
logam aluminium berskala mikro. Kaedah Taguchi digunakan
untuk mereka bentuk eksperimen (DOE) dan analisis. Di
samping itu, kaedah gerak balas permukaan (RSM)
diguna untuk membangunkan model empirikal kelikatan. Nisbah pencampuran serbuk
pengikat yang optimum ialah 58:42 vol. % dengan kelajuan rotor 43 rpm ditentukan untuk menyediakan bahan mentah aluminum PIM menggunakan
pengisar skala kecil. Model empirikal bagi kelikatan bahan mentah aluminum PIM menunjukan
padanan yang baik dengan nilai R2 iaitu 0.84
untuk bahan HDPE dan 0.96 untuk MPDE sebagai
sistem pengikat. Penyelidikan ini menunjukkan cara penyediaan
dan kesesuaian bahan mentah aluminum PIM menggunakan sistem pengikat
berasaskan lilin.
Kata
kunci: Aluminum; campuran serbuk pengikat; kelikatan; pengacuan suntikan;
pengoptimuman
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*Pengarang untuk surat-menyurat; email: imtiaz@um.edu.my