Mohd Ruzi Harun

Effect of element additions on wear property of eutectic aluminium-silicon alloys

Abstract The effects of cerium, zinc and zirconium additions and subsequent heat treatment on wear of the eutectic aluminium-silicon alloys have been investigated in dry sliding against a steel counterface by using a pin-on-disc machine. Wear surfaces and debris were examined by scanning electron microscopy. Wear characteristics of both binary Al-Si alloys and a commercial LM 13 alloy, were also studied and compared with those of the AlSi alloy containing the Ce, Zn and Zr. The k-values of the ALSI (Al-12.3%Si), LM13, ASMC-1 (Al-12.3%Si-0.75%Mg-0.26%Ce) and ASMC-1 (heat-treated) obtained are 5.795 × 10−4, 4.750 × 10−4, 4.311 × 10-4 and 3.981 × 10−4 mm3N−1 m−1, respectively.

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.

Parameter optimization of injection molding Ti-6Al-4V powder and palm stearin binder system for highest green density using Taguchi method

In this paper, the titanium alloy powder of Ti-6Al-4V is mixed with binder 60wt% of palm stearin and 40wt% of polyethylene for metal injection molding (MIM) process. Injection molding parameters has been optimized using Taguchi method of L27 (313) orthogonal array. Highest green density has been identified as the green part quality characteristic or as an output for this study. Parameters optimized are the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed. Besides those, interaction of the injection pressure, injection temperature and powder loading were studied. The analysis of variance (ANOVA) is employed to determine the significant levels (α) and contributions of the variables to the green density. Results show that the injection pressure has highest significant percentage followed by injection temperature, powder loading and holding pressure.

Rheological Investigation of ZK60 Magnesium Alloy Feedstock for Metal Injection Moulding Using Palm Stearin Based Binder System

This paper investigates the characteristic important to metal injection moulding (MIM) process via rheological behavior of MIM feedstock. A gas atomized spherical ZK60 magnesium (Mg) alloy powder and the binder of 60wt.% palm stearin (PS) + 40wt.% low density polyethylene (LDPE) were used in this investigation. Prior to mixing process, critical powder volume percentage (CPVP) was determined and subsequently four different feedstocks with powder loading of 62, 64, 66 and 68vol.% were prepared. The properties of the feedstocks were then analyzed rheologically. Here, the flow behavior index n, the flow activation energy E and the mold ability index αSTV of the Mg alloy MIM feedstocks were determined. Results show that feedstock with 64% powder loading has the best rheological properties and therefore it is considered to be the best for the injection moulding process.

Multiple performance optimization for the best injection molding process of Ti-6Al-4V green compact

The L27 (313) Taguchi orthogonal array is used in the experiment while the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed are optimized in this study. A grey relational grade (GRG) obtained from the grey relational analysis (GRA) is used to solve the titanium alloy powder injection molding operations with the multiple performance characteristics such as strength and density. From the analysis of variance (ANOVA), the injection temperature has the highest contribution at confidence level 90% to the quality of green part followed by powder loading. The others factor such as mold temperature, holding pressure, injection pressure and injection rate and all the interactions are not significant even though it give contribution during injection molding but the confidence level are less than 90%.

Metal injection moulding of ZK60 magnesium alloy powder using palm stearin based binder system

This paper presents a new fabrication process for producing magnesium alloy components via metal injection moulding (MIM). Here, four kind of feedstock with 62, 64, 66 and 68% powder loading were prepared by a mixture of gas atomized ZK60 magnesium alloy powder with a resin consisting of palm stearin and low density polyethylene. The rheological investigation of the feedstock was carried out and the optimal powder loading was determined. The optimal powder loading feedstock was then injected by screw type injection moulding machine. The effects of injection moulding parameters on the physical and mechanical properties of green compacts were evaluated. The results showed that injection moulding of a feedstock containing 64% magnesium alloy was possible at high barrel temperature and pressure.

Optimization of micro metal injection molding by using grey relational grade

Micro metal injection molding (μMIM) which is a variant of MIM process is a promising method towards near net‐shape of metallic micro components of complex geometry. In this paper, μMIM is applied to produce 316L stainless steel micro components. Due to highly stringent characteristic of μMIM properties, the study has been emphasized on optimization of process parameter where Taguchi method associated with Grey Relational Analysis (GRA) will be implemented as it represents novel approach towards investigation of multiple performance characteristics. Basic idea of GRA is to find a grey relational grade (GRG) which can be used for the optimization conversion from multi objectives case which are density and strength to a single objective case. After considering the form ‘the larger the better’, results show that the injection time(D) is the most significant followed by injection pressure(A), holding time(E), mold temperature(C) and injection temperature(B). Analysis of variance (ANOVA) is also employed to st...

The Development of Metal Injection Moulding for ZK60 Magnesium Alloy Using Palm Stearin Based Binder System

In this paper, the development of green compact of ZK60 magnesium alloy was studied in the context of MIM using screw type injection moulding machine model Battenfeld BA250CDC. The MIM feedstock used was 64 vol.% powder loading and the balance was palm stearin and low linear density polyethylene with the fraction of 60/40 by weight percent. The injection moulding parameters were then adjusted until the optimal condition of green part was accomplished. Results indicate that the feedstock exhibited good workability when injection moulded at the temperature of 190°C, injection pressure of 900kN, flow rate of 15,5cm3/s and with a very low ejection parameters. This technique provides an additional means to manufacture magnesium alloy components for a wide variety of applications.

Optimizing the Sintering Parameter of Metal Injection Molding Compact Using Robust Engineering Technique

Sintering is a key step in the metal injection molding (MIM) process, which affects the mechanical properties of the sintered part. The mechanical properties of the sintered compacts are resulted from tremendous sintered part densification. This work utilizes robust engineering technique in optimizing sintering parameters of metal injection molding compacts. Three quality characteristics; shrinkage, density and flexure strength is optimized using Taguchi method-based grey analysis. The modified algorithm adopted here was successfully used for both detraining the optimum setting of the process parameters and for combining multiple quality characteristics into one integrated numerical value called grey relational grade. The sintering parameters investigated are: sintering temperature, sintering time, and heating rate. The result concluded that sintering time is the most significant for the combination of the quality characteristics.