Prediction of Weld Bead Geometry for Small-Wire Submerged Arc Welding in 1G position / Ghalib Tham...[et al.]

Small-wire Submerged Arc Welding (SAW) is a low-cost alternative to the conventional SAW. In robotic or mechanized welding system, the welding bead geometry and welding parameter have to be known before welding. Developing them by trial and error is costly and wasteful practice in the long run. Therefore, there is a need to develop a tool to predict the correct bead geometry. A robotic small-wire SAW was employed to deposit bead-on-plate on carbon steel in 1G position, using a range of welding parameter permitted by the power source. Quality welded samples were cut at cross-section, polished and etched to display their macrostructure. The bead geometry was measured; the correlation between bead geometry and heat input was plotted. Without considering the bead penetration, the measured values of bead geometry are found to be quite scattered about the trend line, except the bead width. By applying the trend-line equations in prediction of bead geometry, only the bead width can be predicted accurately, where the deviation between predicted bead width and measured bead width is consistently less than 1mm. By grouping the measured bead geometry data based on 5 levels of bead penetration, when plotting the bead geometry with respect to heat input, all the bead geometry data aligned closely along their respective trend-lines, thus all elements of bead geometry can be predicted with high accuracy. The deviation of all elements of bead geometry and the values of mean average deviation (MAD) is less than 1mm

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

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

Feedstock characterisation of titanium alloy mix with palm stearin binder system for metal injection moulding

This paper presents the characterization of MIM feedstock consisting 90wt% of titanium alloy (Ti-6Al-4V) powder mix with binder 60wt% palm stearin and 40wt% polyethylene. The characterization of Ti-6Al-4V alloy powder, binders and feedstock includes scanning electron micrograph (SEM), thermogravimetric analysis (TGA), differential scanning calorimeter (DCS) and rheological test were established. Rheological results exhibited pseudoplastic or shear thinning flow behaviour, where its viscosity decreased with increasing shear rate. The feedstock viscosity also decreased with increasing temperature and was found to be suitable for mouldin

Metal Injection Moulding, orthogonal array, analysis of variance, flexure strength, sintering

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. The success of injection molding is greatly influenced by feedstock characteristic.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 both green strength and green density were 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 injection temperature(AxB). Single factor that also contributes to significant optimization are mold temperature(C), injection time(D) and injection pressure(A). This study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials

Rheological characterization of water atomised stainless steel powder for micro metal injection molding

In this paper, the performance of feedstock characteristics for micro metal injection molding (µMIM) is investigated by optimum power loading variation and rheological characterization. Due to the highly stringent characteristics of µMIM’s feedstock, the study has been emphasized on the powder and binder system in which stainless steel SS316L powder are mixed with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid) by variation of powder loading concentration. The rheology properties are investigated using Shimadzu Flowtester CFT-500D capillary rheometer. The geometry of water atomised stainless steel powder are irregular shape, therefore it is expected significant changes in the rheological results that can influence the microcomponent, surface quality, shape retention and resolution capabilities. The optimization of the µMIM rheological properties as a function of stainless steel powder loading concentration are evaluated by flow behavior exponent, activation energy and moldability index. Results show that 61.5%vol contributes a significant stability over a range of temperature and the best powder loading from a critical powder volume percentage (CPVP) and rheological point of vie

Injection molding parameter optimization of titanium alloy powder mix with palm stearin and polyethylene for green defects using taguchi method

This paper outlines the Taguchi Method using L?? (3??) orthogonal array, which is applied to optimize injectin molding parameters in Metal Injection Molding (MIM) process using titanium alloy powder mix with palm stearin and polyethylene. Parameters optimized were injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed. Classical analysis of variance (ANOVA) for the smallest the best signal to noise ratio (S/N) presents the significance of each parameters and interaction. A green defects was assumed to be the quality characteristics (response) and it has been measured using parameter design for discrete data technique. From the ANOVA, the injection pressure has the highest percentage of contribution to the green defects followed by interaction of injection pressure-powder leading and interaction of injection pressure-injection temperatur

Flow behaviour to determine the defects of green part in metal injection molding

The paper describes author’s work on the investigation of the molding flow behaviour to determine the defects of green part in metal injection molding (MIM) using powder of carbonyl iron (CIP-S-1641) mix with polymer-based binder, Hostamont EK583 at different powder loadings. Rheological properties of the feedstock were presented in this paper. Results show that all feedstock have good pseudoplastic behaviour, which is suitable to be injection molded. Since the flow behaviour of the feedstock in molding cannot solely depends on the rheological test especially in control the quality of green part, this paper also investigate the molding practice via using MOLDFLOW software and compared with the actual experiment. After molding practice the results shows some defects still occurred on green part and it has been control by proposed the optimum molding parameters such as injection temperature and injection pressure

Orthogonal array technique for optimizing the sintering parameter of the metal injection molding (MIM) compact: best flexure strength

Sintering is a key step in the metal injection moulding (MIM) process, which affects the mechanical properties of the sintered part. The mechanical property of the sintered compact is resulted from tremendous sintered part densification. The paper presents an optimisation of the sintering parameter for the best flexure strength of the fine SS316L water atomised powder compact. The L9 (34) orthogonal array is used in the study and four replication of the flexure strength has been recorded at each experiment trial. The analysis of variance (ANOVA) shows the sintering variables are highly significant to the flexure strength, a = 0.005. The study demonstrates that the cooling rate is the most influential variable that contributes to the best flexure strength, followed by heating rate, dwell time and sintering temperatur