Kebolehacuanan suntikan logam mikro SS 316L menggunakan bahan pengikat PEG dan PMMA Mohd

Pengacuanan suntikan logam mikro atau lebih dikenali µMIM merupakan satu proses yang berkesinambungan daripada proses penyuntikan logam. Proses ini menggunakan serbuk logam bersaiz mikro dan mampu menghasilkan produk mikro yang kompleks pada kuantiti yang banyak serta yang memerlukan kepersisan permukaan yang tinggi dan jitu. Penggunaan saiz serbuk logam mikro akan meningkatkan nilai kelikatan bahan suapan yang mana ia merupakan cabaran utama di dalam proses µMIM yang akhirnya akan menyukarkan proses penyuntikan. Selain itu, ia juga akan meningkatkan peratusan kadar pengecutan dan kandungan oksigen jasad sinter. Oleh itu, kajian ini bertujuan untuk mengoptimumkan parameter setiap proses berdasarkan kepada teknik Rekabentuk Eksperimen agar dapat menghasilkan jasad sinter yang berketumpatan tinggi dan kuat, rendah kandungan oksigen, kurang kecacatan serta kadar pengecutan yang minima. Bahan pengikat yang terdiri daripada 73vol% Polietilena Glikol (PEG), 25vol% Polimetil Metakrilate (PMMA) dan 2vol% Asid Stearik di campur dengan SS 316L bersaiz mikro bagi menghasilkan bahan suapan yang homogen dan sekata. Analisis kebolehaliran bahan suapan dikaji melalui sifat reologinya pada suhu 130- 150°C iaitu suhu peleburan yang dicatatkan melalui ujian DSC. Pembebanan serbuk pada 61.5% menunjukkan pembebanan yang paling optimum kerana ia menyumbang kepada sifat pseudoplastik, kelikatan dan indeks tingkahlaku aliran yang sekata, nilai tenaga pengaktifan yang rendah serta indeks kebolehacuan yang tinggi seperti mana yang diperlukan di dalam µMIM. Analisis varian (ANOVA) dilakukan di dalam setiap proses penyuntikan, penyahikatan larutan, penyahikatan terma dan pensinteran bagi mengenal pasti parameter yang paling signifikan dan sumbangannya terhadap ciri kualiti yang dikaji iaitu ketumpatan dan kekuatan lentur dengan hanya parameter kajian melepasi aras keyakinan 90% sahaja yang diambil kira. Melalui ujian ANOVA di dalam penyuntikan, 3 interaksi menunjukkan kesignifikan iaitu tekanan penyuntikan, suhu penyuntikan dan suhu acuan manakala masa penyuntikan dan masa pegangan dikekalkan sebagai parameter tunggal. Interaksi antara suhu penyuntikan dan suhu acuan merupakan penyumbang terbesar di dalam kedua-dua kaedah tersebut. Penyingkiran bahan pengikat sekunder iaitu PEG dilakukan melalui proses penyahikatan larutan pada suhu 55-65°C dengan masa rendaman antara 2-6 jam. ANOVA menunjukkan hanya 4 parameter yang signifikan di dalam proses ini iaitu masa penyahikatan, suhu penyahikatan, masa penyuntikan dan tekanan penyuntikan manakala tiada interaksi yang signifikan direkodkan di dalam proses ini. Analisis pengoptimuman menggunakan kaedah Grey-Taguchi menunjukkan masa penyahikatan adalah penyumbang terbesar diikuti oleh suhu penyahikatan iaitu sekitar 39%. Disebabkan oleh pengendalian yang amat teliti diperlukan di dalam komponen mikro, 2 proses seterusnya telah digabungkan iaitu penyahikatan terma dan pensinteran dengan menggunakan relau vakum bagi mengelakkan sebarang pengoksidaan berlaku. Bagi kedua-dua proses ini, 6 parameter dikenalpasti signifikan iaitu suhu pensinteran, masa pensinteran, kadar pensinteran, suhu penyahikatan, masa penyahikatan dan kadar penyahikatan dengan 3 interaksi diambilkira pada tatacara ortogonal L27(313). Melalui kaedah pengoptimuman Grey-Taguchi ini, kekuatan dan ketumpatan jasad sinter berjaya ditingkatkan sehingga 96.79% daripada ketumpatan piknometer. Di samping itu juga, proses pengoptimuman ini juga berjaya meminimakan kadar pengecutan jasad sinter sehingga 11.75% berbanding kajian oleh penyelidik terdahulu yang mana ia berada diantara 16-20%. Kandungan oksigen juga dapat diminimakan sekitar 2300 ppm iaitu di dalam julat yang dibenarkan oleh piawaian ASTM E101

Green strength optimization of injection molding proces for novel recycle binder system using Taguchi method

Metal injection molding is a worldwide technology that world use as a predominant method in manufacturing. Optimizing the injection molding process is critical in obtaining a good shape retention of green components and improving manufacturing processes itself. This research focuses on the injection molding optimization which correlated to a single response of green strength which implementing orthogonal array of Taguchi L9 (34). It involved the effect of four molding factors: injection temperature, mold temperature, injection pressure and injection speed, towards green strength. The significant levels and contribution to the variables of green strength are determined using the analysis of variance. Manual screening test is conducted in regards of identifying the appropriate level of each factors. The study demonstrated that injection temperature was the most influential factor contributes to the best green strength, followed by mold temperature, injection speed and injection pressure. The optimum condition for attaining optimal green strength was definitely by conducting injection molding at; 160 ºC of injection temperature, 40 ºC of mold temperature, 50 % of injection pressure and 50 % of injection speed. The confirmation experiment result is 15.5127 dB and it was exceeding minimum requirement of the optimum performance. This research reveals that the proposed approach can excellently solve the problem with minimal number of trials, without sacrificing the ability of evaluating the appropriate condition to achieve related response, which is green strength

Critical Powder Loading and the Rheology of Nanosized Cemented Carbide with Titanium Carbide as Grain Growth Inhibitor for Injection Molding

The purpose of this paper is to determine the critical powder loading of WC-Co and to study the effect of TiC powder on the rheological behavior of MIM feedstock. WC-TiC-6Co metal powder was taken as raw material. 60% (mass fraction) palm stearin and 40% low density polyethylene were employed as binders to prepare injection feedstock. Three feedstocks were prepared at different TiC % loadings of 0.5, 0.75, and 1.0 (by weight). A homogeneous metal powders is formed by using ball mill mixer and mixed together with binder system by using Brabender mixer. Based on the result obtained, it was concluded that feedstock with 0.75 wt.% TiC powder show a good pseudo-plastic behavior within acceptable ranges in MI

A Review of Metal Injection Moulding on WC-Co Cemented Carbide Comprised of Grain Growth Inhibitors (GGI)

This paper aims to provide a summary of metal injection moulding technologies utilising cemented WC-Co carbides comprised of grain growth inhibitors (GGI). The advanced manufacturing of metal injection moulding (MIM) has the ability to produce cement nanostructured carbides. In addition, the nature of the feedstock plays a crucial role when manufacturing a defect-free component at each point of the MIM phase, thus the interactions between the metal powder and the binder combining, moulding, and debinding are important to be recognised. The primary objective of this analysis is to investigate the characterization of feedstock to form a homogenous mixture. There are five criteria to classify features of the feedstock which include powder characteristics, binder composition, powder content ratio, mixing cycle, and approaches to palletization. Not only that, the feedstock must meet specific criteria; higher powder loading with excellent flowability by the rheological approaches. The second goal of the research is to re-evaluate feedstock’s flow properties in relation to rheological activity in terms of index flow behaviour (n), activation energy (E), and mouldability (α). MIM practitioners have continued to underestimate erratic product quality, including inadequate regulation, distortion, and internal and external defects. These defects can arise in the early processing phases, but often occur only after sintering or debinding. The approaches are also challenging to provide. This chapter includes a description of MIM defects. Explanations are listed and recommendations are provided for these defects

Virgin kraft pulp and paper characteristics of Vitex Pubescens Vahl. (Halban) wood

Insufficient wood-based materials due to environmental sustainability have further enhanced the search for alternatives in the paper industry. Thus, wood sample from Vitex Pubescens Vahl (Halban) was evaluated based on the pulp characteristics; and paper physical, mechanical and optical properties as alternative raw material for papermaking. The wood chips were chemically Kraft cooked. Laboratory hand sheet with 120 gsm of grammage was produced without beating and bleached treatment. Overall procedures and tests were conducted according to the Technical Association of the Pulp and Paper Industry (TAPPI) and the Malaysian International Organization for Standardization (MS-ISO). The result shows that Halban virgin Kraft pulp recorded a value of screened yield percentage (38.6%), Kappa number (22.1), drainage time (6.44s), and Canadian Standard Freeness (555ml). Halban paper sheet has apparent density of 0.302g/cm3. In an optical analysis, brightness (19.81%) and opacity (99.5%) had been measured. Mechanical characteristic possess considerable tensile index (29.33Nm/g), tear index (6.028 mN.m2/g), burst index (1.04 kPa.m2/g), but low folding no (3). In conclusion, Halban wood could be considered as alternative wood-based material for papermaking based on its promising characteristics’ and also compatible with other wood-based material proposed by the previous study. However, more in-depth evaluation should be considered to improve the qualities of the pulp and paper made from Halban wood

Parameter optimization towards highest micro MIM density by using Taguchi method

Nowadays, micro metal injection molding has become among the promising method in powder metallurgy research to produce small-scale intricate part at an effective process and competitive cost for mass production. This paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. In this paper, stainless steel SS 316L with D50 = 5.96µm was used with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid). Feedstock with 61.5% with several injection parameters were optimized which highly significant through screening experiment such as injection pressure(A), injection temperature(B), mold temperature(C), injection time(D) and holding time(E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchi’s orthogonal array. Analysis of variance (ANOVA) in terms of signal-to-noise ratio (S/N-larger is better) for green density was also presented in this paper. Result shows that interaction between injection temperature and mold temperature(BxC) give highest significant factor followed by interaction between injection pressure and mold temperature(AxC). Single factor that also contributes to significant optimization are mold temperature(C) and injection time(D). This study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials

An influence of the SS316L powder particle shape to the densification of metal injection moulding (MIM) compact

Metal injection molding (MIM) has acquired increasing importance as a production technique for small, complex stainless steel components [1, 2]. Sintering is critical for determining the final quality of the parts produced by MIM. Because high sintered density is imperative for good mechanical properties and corrosion resistance, achieving full or near-full density has been a major objective of sintering [3]. Therefore, most research on 316L stainless steel sintering to date has focused on the sintering behavior of the molded parts especially for gas-atomised powder in argon environment [3-6]. An understanding of the factors influencing densification of stainless steels is important as over 50% of the injection molded and sintered components are made from stainless steel compositions [7]. In a metal injection molding (MIM) process, gas-atomised powder is generally used due to their high packing density and associated feedstock rheology. The sintered components exhibit mechanical and corrosion properties similar or superior to that of wrought material. Water-atomised powders in MIM can be economical and have an improvement in shape retention during debinding and sintering. However, their use comes with a penalty of lower powder loading and sintered density, with a corresponding degradation in the mechanical and corrosion properties. Studies reveal that injection molded and sintered components using water-atomised 316L stainless steel powders have a residual porosity of 3–5% for similar particle characteristics and sintering conditions as that of gas-atomised powders [5]. This article investigates a densification of SS316L gas and wateratomised compact sintered in high vacuum environment at temperature ranging from 1340 to 1400 °C

Soda-anthraquinone durian (durio zibethinus murr.) rind linerboard and corrugated medium paper: a preliminary test

A preliminary test was conducted to investigate the characteristics of linerboard and corrugated medium paper made from durian rind waste. Naturally dried durian rinds were pulped according to Soda-Anthraquinone (Soda-AQ) pulping process with a condition of 20% active alkali, 0.1% AQ, 7:1 liquor to material ratio, 120 minutes cooking time and 170°C cooking temperature. The linerboard and corrugated medium paper with a basis weight of 120 gsm were prepared and evaluated according to Malaysian International Organization for Standardization (MS ISO) and Technical Association of the Pulp and Paper Industry (TAPPI). The results indicate that the characteristics of durian rind linerboard are comparable with other wood or non-wood based paper and current commercial paper. However, low CMT value for corrugated medium and water absorptiveness quality for linerboard could be improved in future. Based on the bulk density (0.672 g/cm3), burst index (3.12 kPa.m2/g) and RCT (2.00 N.m2/g), the durian rind has shown a good potential and suitable as an alternative raw material source for linerboard industry

Kajian prestasi penyahikatan larutan dengan menggunakan kaedah taguchi

Proses penyahikatan larutan telah diterima secara meluas dalam proses pengacuan suntikan logam (MIM) berdasarkan kepada kemampuannya yang dapat mempercepatkan proses penyahikatan. Kertas kerja ini akan membentangkan pengoptimuman proses tersebut dengan menggunakan kaedah Taguchi. Selain daripada itu juga, pengaruh faktor-faktor yang digunakan dalam kajian ini seperti suhu larutan, taburan saiz partikel, beban serbuk dan tekanan penyuntikan akan dibincangkan. Dua jenis serbuk logam akan digunakan dalam kajian ini iaitu serbuk SS316L pengatoman gas dan SS316L pengatoman air. Keputusan kajian ini mendapati bahawa suhu larutan yang digunakan untuk merendam jasad anum semasa proses penyahikatan larutan memainkan peranan yang besar sebanyak 91.602 % (serbuk SS316L pengatoman gas) dan sebanyak 84.978 % (serbuk SS316L pengatoman air) ke atas kadar penyahikatan larutan. Bagaimanapun, taburan serbuk logam hanya menyumbangkan sebanyak 6.638 % dan 12.228 % masing-masing bagi jasad anum serbuk SS316L pengatoman gas dan pengatoman air terhadap kadar penyahikatan tersebut. Suhu larutan untuk merendam jasad anum ini juga mempunyai tahap signifikan yang amat tinggi iaitu sebanyak 0.5% bagi kedua-dua jenis serbuk SS316L tersebut. Akan tetapi, taburan saiz partikel serbuk SS316L menunjukkan tahap signifikan yang sederhana tinggi iaitu 2.5% dan 1% bagi serbuk SS316L pengatoman gas dan pengatoman air masing-masing

Effects of total chlorine free (TCF) bleaching on the characteristics of chemi mechanical (CMP) pulp and paper from Malaysian durian (DURIO ZIBETHINUS MURR.) rind

The effects of bleaching process on the characteristics of pulp and paper produced from durian rind under chemi-mechanical pulping (CMP) method were investigated. All process and characteristic tests were conducted according to Malaysian International Organisation for Standardization (MS ISO) and Technical Association of the Pulp and Paper Industry (TAPPI). Three (3) stages of peroxide (P-P-P) bleaching sequence through the Total Chlorine Free (TCF) bleaching process were applied to the unbeaten and unbleached durian rind CMP pulp. Bleached CMP durian rind pulp drainage time (32s) decreased (faster) and CSF freeness level (172.50ml) increased as compared to a control pulp. It was obtained that overall optical (brightness (66.36 %)) and mechanical characteristics (tensile index (38.33 Nm/g), tearing index (7.56 mN.m2/g), bursting index (2.42 kPa.m2/g), and number of folds (43)) of durian rind CMP 60 gsm paper sheet improved as the TCF bleaching process was applied to the unbleached CMP durian rind pulp