Mohd Razali Muhamad

Development of genetic algorithm on multi-vendor integrated procurement-production system under shared transportation and just-in-time delivery system

One of the well-known inventory control techniques utilized in the supply chain is integrated inventory model. Recently, previous research [Z.X Chen and B.R Sarker, Multi-vendor integrated procurement-production system under shared transportation and just-in-time delivery system, Journal of the Operational Society 61 (2010) 1654-1666] have developed an integrated model to synchronize the production flow from multi-vendor to manufacturer through shared transportation. However, the model is complex to find the optimal solution. Because of these complexities, simplifications of the model are often based on limiting assumptions. Since the model is a non-linear integer programming type, this paper addresses genetic algorithm to overcome the limitations to find batch production lot size of vendors and manufacturer, delivery quantities and number of deliveries from different vendors to the manufacturer in order to minimize total cost of all parties involved in the supply chain. Furthermore, a numerical example is presented to illustrate the results.

Modeling of TiN Coating Thickness Using ANFIS

In this paper, an approach in predicting thickness of Titanium Aluminum Nitrite (TiN) coatings using Adaptive Network Based Fuzzy Inference System (ANFIS) is implemented. The TiN coatings were coated on tungsten carbide (WC) using Physical Vapor Deposition (PVD) magnetron sputtering process. The N2 pressure, argon pressure and turntable speed were selected as the input parameters and the coating thickness as an output of the process. Response Surface Methodology (RSM) was used to design the matrix in collecting the experimental data. In the ANFIS structure, three bell shapes were used as input membership function (MFs). The collected experimental data was used to train the ANFIS model. Then, the ANFIS model was validated with confirmatory test data and compared with other prediction models in terms of the root mean square error (RMSE), residual error and prediction accuracy. The result indicated that the developed ANFIS model result was the lowest RMSE7 and average residual error, besides the highest in prediction accuracy compared to the other models. The result also indicated that the limited experimental data could be used in training the ANFIS model and resulting accurate predictive result.

Understanding Time Loss in Manufacturing Operations

Nowadays, manufacturing high product variety is essential for manufacturing companies in order to be sustainable in a volatile market. However, maintaining a shorter lead time in manufacturing operations is also crucial as the speed delivery becomes one of the manufacturing competitive priorities. Motivated by this issue, this study aims to develop a model of Time Loss (TL) for sub-assembly processes in automotive industry. In relation to this, critical elements of TL will be clearly justified through a thorough analysis of literature study in the aspects of Man, Machine, Method, and Material (4M). In this study, the critical elements of TL is defined as an unnecessary activity that needs to be eliminated or minimized. The relationships between the critical elements of TL are clarified through the flow of activities involved in the concept of manufacturing input-output. Finally, the critical elements of TL are compared to the existing non-financial manufacturing performance measures presented in isolated models (e.g. leanness, agility, responsiveness, etc.). Results of the analysis show that the critical elements of TL can be represented as a holistic performance measure of manufacturing operations that includes leanness, agility, fitness, responsiveness, flexibility, and sustainability.

The Effect of EDM Die-Sinking Parameters on Material Characteristic for Aluminium Composite Using Tungsten Copper Electrode

The machining ability of electrical discharge machining (EDM) die-sinking on aluminium LM6 (Al-Sil2) as a new material is investigated.The objective of this paper is to determine the relationship between the machining parameters which are pulse-on time, pulse-off time and peak current on the material characteristics such as material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra). Tungsten copper tool of diameter 10mm was chosen as an electrode. Design of experiment using Taguchi method was used to develop experimental matrix and optimize the MRR, EWR and Ra. The analysis was done using the Minitab software. It is found that the current and pulse on time are significantly affected the MRR, EWR and Ra while pulse off time and voltage are less significant factor that affected the responses. From the Taguchi method, the best setting of optimum value was obtained. Thus, it shows that Taguchi method is the best quality tools that can be applied for production.

Phase Transformation of P91 Steels upon Cooling after Short Term Overheating above Ac1 and Ac3 Temperature

Advanced ferritic steels containing 9 wt% Cr are widely used in the construction of supercritical and ultra supercritical boiler components. Grade 91 is one of the most common alloys used in this application. The microstructure of the as supplied 91 materials consists of a tempered martensite matrix, a fine dispersion of intergranular chromium rich M23C6 precipitates and intragranular carbonitrides MX particles rich in V and Nb. This steel requires post weld heat treatment (PWHT) to produce a tempered microstructure after welding to develop excellent creep strength for high temperature service. Based on past experience, situations may arise whereby the components are subjected to an accidental ‘overshoot’ in temperature during PWHT. The consequence is the formation of deleterious phases which will result in undesirable changes in material property. In this research, P91 base metal specimens were heated to various peak temperatures in a laboratory furnace. Heat treatment parameters, as practiced at site, were applied. Peak temperatures applied were below Ac1, between Ac1 and Ac3, and above Ac3. Hardness measurement demonstrated a significant reduction once the Ac1 temperature was exceeded, due to the presence of soft α-ferrite matrix. As the temperature was increased towards Ac3, newly transformed fresh martensite which is hard and brittle in nature would form the dominant matrix. The phase transformation and precipitate morphology changes were studied using optical microscopy and scanning electron microscopy techniques. Three factors were identified to determine the phase transformation: (1) the homogeneity level and amount of precipitates dissolved in austenitic matrix upon heating; (2) slow cooling rate that may shift the cooling curve to enter ferrite nose and (3) deviation in chemical composition.

The impact of the bilayer TaN/Ta barrier at the copper seed and copper electroplating process in semiconductor fabrication

Copper metallization process, using electroplating, in Integrated Circuit interconnect, poses big challenge in semiconductor fabrication. Besides the stringent Dual Damascene requirement, the copper material itself is prone to rapid interface diffusion as well as surface oxidation. Thus the copper metallization process has to be performed within specific time after copper seed deposition process. This study investigated the impact of bilayer TaN/Ta barrier on copper sheet resistance changes at different time intervals. The study was based on 200mm wafer. In addition to that, correlation between sheet resistance to other copper film properties such as reflectance and stress was also investigated. Based on results of this study, bilayer TaN/Ta barrier inclusion in copper seed greatly improved film sheet resistance stability.

Fit manufacturing: Production Waste Index and its effect on Production Profitability

Rapid changes of market demands resulted in emergence the numbers of manufacturing concept; i.e. Lean Manufacturing (LM), Agile Manufacturing (AM), Responsive Manufacturing (RM), Reconfigurable (ReM), and Sustainable Manufacturing (SM). However, the models of manufacturing concept have been presented independently. In this study, the model of Fit Manufacturing (FM) concept is developed through the integration of three models of manufacturing concept: (i) LM, (ii) AM, and Sustainability concepts. In FM, Production Fitness represents as the performance measure of production operations that determined by integration of measure for Leanness, Agility, and Sustainability. The objective of this paper is to discuss the effect of Production Waste Index (PWI) on Production Profitability Index (PPI). In this regard, PWI represents as the measure of Leanness that based on the LM concept. PWI indicates the level of production wastes which are determined through accumulation of seven types of Lean production wastes. PPI represents the size of profit margin that affected by production costs. A case study at six micro-SMEs in Malaysia had been conducted to validate the PWI model. Results of the case study proved that the PWI has effect on PPI in which the effective capacity in the main influence factor. In conclusion, this research contributes to development of measurement index for production waste and profitability that can be used as an indicator to monitor the production effectiveness.

A Conceptual Framework in Determining Manufacturing Complexity

This paper proposes a conceptual framework in determining manufacturing complexity. Manufacturing complexity is divided into five main components which are product behaviour, infrastructure capability, production planning, information management and personnel perception. These five main components then divided into twelve sub components. Lastly all these components are classified in two categories which are internal complexity and external complexity. These components are interrelated, such that a bi-directional relationship exists between internal and external complexity. The conceptual framework initiated in this paper can be used by manufacturers to gain more understanding on manufacturing complexity. Thus manufacturers can take proper actions to align themselves with the issues brought forth by manufacturing complexity.

Mechanical Properties of Oil Palm Empty Fruit Bunch Fibers-Cast Alloy Composite Using Three Point Bending Test

This paper presents the mechanical properties of oil palm empty fruit bunch (OPEFB) fiber/epoxy resin reinforced cast LM6 (aluminum based) alloy composites. The metal matrix composite was fabricated by incorporating OPEFB/epoxy resin using mono filaments concept in the as cast LM6 alloys. Three different diameters (10, 12 and 14 mm) of the maximum force of metal matrix composite materials along with controlled sample (cast LM6 alloy + OPEFB/epoxy resin) were determined from three point bend testing. Test results showed that maximum force of mixture between OPEFB fibers composite and cast LM6 alloy for metal matrix composite are higher than that of cast LM6 alloy. Thus the utilization of OPEFB/epoxy composite as mono filaments in metal matrix composite can be significant in improving the strength of the cast LM6 alloy. Beside that increasing the diameter size of OPEFB/epoxy composite will reduce the weight of metal matrix composite (cast LM6 + OPEFB/epoxy composite).

Effect of Different Coolant Medium on Warpage Deflection Using Moldflow Insight Analysis

The effect of mould temperature on warpage using water and oil as coolant fluid was studied using flow software analysis. Mould temperature was controlled using two types of coolants; where cold mould was controlled by water and hot mould was controlled by oil. The simulation analysis was performed using flow software analysis Moldflow Plastics Insight (MPI). Taguchi method was used to design the planning matrix and to find the optimum levels of input variables. Then, to find the percentage contribution of input variables on output variables, analysis of variance (ANOVA) was used. It is found that mould temperature controlled by water shows less warpage analysis compared to oil. The minimum and maximum percentage of warpage analysis between cold mould and hot mould are 3.1% and 7.1% respectively. In addition, ANOVA analysis shows that the most significant parameters affected the warpage analysis for both moulds using oil and water are melt temperature (255°C) followed by mould temperature (water 15°C and oil 70°C) and cooling time (water 8s and oil 6s). Thus, it shows that coolant medium used in mould cooling system contributes the quality of plastic parts.