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

Received: 22 May 2016/Accepted: 17 August 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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*Corresponding author; email: imtiaz@um.edu.my