Applied Mechanics and Materials Vol. 315

Abstract: Drying kinetics of kenaf core was investigated in a Low Temperature and Humidity Chamber Test. The drying experiments were carried out at temperature of 45, 50 and 55°C and air relative humidity of 10, 20 and 30% using a constant air velocity of 1.0 m/s. The moisture content data at various drying air conditions were converted to moisture ratio and plotted against time to obtain the drying curves for each experimental data. The curves were fitted to eight different thin layer drying models to determine a suitable model for drying of kenaf core. The fit quality of the models was evaluated based on their coefficient of determination (R²), reduced chi-square (χ²) and root mean square error (RMSE). Among the eight models, Two Term model is the best model for describing the drying behavior of kenaf core. The drying air temperature gave more significant effect on the drying kinetic of kenaf core compared to the drying air relative humidity under the experimental conditions studied.

Abstract: The design and development of a natural illumination device (NID) for Malaysian roofing system is explored and improved with the aid of Lumen Method Approach at the analysis stage. The aim of this research is to channel and distribute natural sunlight from exterior to interior building to enlighten the required space in a daytime. It is made up of three main parts; dome as light collector, light tube as light reflector and light diffuser as light distributor. The result shows illuminance level for the NID in full summer sun and overcast summer sun conditions are higher than T8 fluorescent lamp.

Abstract: Composites of TiC and TiB₂ (TiC-TiB₂) were prepared by self-propagating high-temperature synthesis (SHS), using compacted reactant different combinations of Ti, C, and B powders. It is very difficult to densify these materials using conventional sintering techniques. It was found that the chemical reaction between the starting Titanium, boron and carbon particles could be completed at 1200°C producing a pure TiB₂+TiC ceramic composite. Various carbon content causes the microstructure of the final products was different.

Abstract: The characterization of Chalawa river sand with its suitability for foundry applications has been investigated. Chemical and sieve analyses and Green permeability were determined for the sand via standard procedure. Based on the result of the chemical and sieve analyses and permeability (the sand by its high silica content and low alkali fluxes) it needs small amount of binder, has moderate refractoriness and therefore, can be employed in foundry applications.

Abstract: A method of solid-state recycling aluminum alloy using hot press forging process was studied as well as the possibility of the recycled chip to be used as secondary resources. This paper presents the results of recycled AA6061 aluminium alloy chip using different operating temperature for hot press forging process. Mechanical properties and microstructure of the recycled specimens and as-received (reference) specimen were investigated. The recycled specimens exhibit a good potential in the strength properties. The result for yield strength (YS) and ultimate tensile strength (UTS) at the minimum temperature 430°C is 25.8 MPa and 27.13 MPa. For the maximum operating temperature 520°C YS and UTS are 107.0MPa and 117.53 MPa. Analysis for different operating temperatures shows that the higher temperatures giving better result on mechanical properties and finer microstructure. The strength of recycled specimen increases due to the grain refinement strengthening whereas particle dispersion strengthening has minor effects. In this study, the recycled AA6061 chip shows the good potential in strengthening as the comparison of using only 17.5% of suggested pressure (70.0/400.0) MPa, the UTS exhibit 35.8% (117.58/327.69) MPa. This shows a remarkable potential of direct recycling by using hot press forging process.

Abstract: Spare parts inventory management is very important to ensure smooth operation of maintenance department. The main objectives of inventory management of spare parts are to ensure the availability of spares and materials for the maintenance tasks and increase the productivity of the maintenance department. This research centred on the development of the Computerised Inventory Management System (CIMS) for the maintenance team at Weida Integrated Industries Sdn. Bhd. The inventory management technique used to control the spare parts inventory in this research was the basic Economic Order Quantity models (EOQ). However, the CIMS developed is unique as it has the ability in handling inventories in multiple-storage locations. The CIMS was written using the Visual Basic 2010 software. This CIMS has the abilities to keep records and process the spare parts information effectively and faster besides helping the user to perform spare parts ordering tasks compared to the current manual recording. In addition, the ordering quantity and frequency for the CIMS is determined through the EOQ technique. However, observation indicates that the overall average inventory level currently at the factory is lower than the expected overall average inventory level produced by the CIMS. This is due to the fact that the CIMS was unable to consider the opening stock in ordering the inventories. Therefore, further improvements are needed to optimize the performance of the system such as using the EOQ with the reorder point technique, the periodic or continuous review system.

Abstract: Metal spinning can be used to produce hollow, axially symmetric sheet metal parts with low tooling and production costs, high flexibility, and low waste. Spinning parameters determine the quality of the spinned parts and are of interest for enabling the spinning of thick sheet metals. In this study, conventional metal spinning was conducted on a 6 mm thick low carbon steel with process below its recrystallization temperature to fabricate tube head, requiring maximum deflection of about 90º at its edge. Spinning parameters varied were temperature (at room temperature and 300°C), feed (2 mm and 5 mm), and spinning speed (200 rpm and 250 rpm). Evaluation was made on the resulted surface morphology, thickness variation, and further analysis on hardness and microstructure of the spinned tube head. The resulted tube heads were of acceptable quality in terms of surface morphology and thickness variation, while hardness and microstructure analysis showed that inner parts of the workpiece were not affected by the spinning process.

Abstract: This paper discussed on the determination of important parameters and technical characteristic for the development of a welding fumes index by using Quality Function Deployment (QFD) approach. Welding fumes index is developed with the objective to enhance the welding workplace safety and health. Index simplifies complex health-hazard issues of welding fumes to be comprehended easily by the employees. Questionnaires on welder desire to know the various welding fumes health effects that exist in their workplace were distributed among welders of a selected automotive assembly lines in the state Pahang, Malaysia, during a pilot case study. Results of the questionnaires show that all the customer requirements (irritants effect, sensitizer effects, respiratory system effect, systemic toxin effect, reproductive toxins effect, carcinogen effect, mixture effect) were equally important to the welders. The relationship between the customer (welder) requirement and technical characteristic were established whereby important technical characteristics were shortlisted. Development of welding fumes index according to employees demand will increase the knowledge and awareness on occupational safety and health among employees. The paper provides the main idea on development of welding fumes index taking into consideration the needs of the customer i.e. welder.

Abstract: Performance of machining processes is assessed by dimensional and geometrical accuracy which is mentioned in this paper as dimensional deviation. A part quality does not depend solely on the depth of cut, feed rate and cutting speed. Other variable such as excessive machine tool vibration due to insufficient dynamic rigidity can be deleterious to the desired results. The focus of the present study is to find a correlation between dimensional deviation against cutting parameters and machine tool vibration in dry turning. Hence cutting parameters and vibration-based regression model can be established for predicting the part dimensional deviation. Experiments are conducted using a Computerized Numerical Control (CNC) lathe with carbide insert cutting tool. Vibration data are collected through a data acquisition system, then tested and analyzed through statistical analysis. The analysis revealed that machine tool vibration has significant effect on dimensional deviation where statistical analysis of individual regression coefficients showed p<0.05. The developed regression model has been validated through experimental tests and found to be reliable to predict dimensional deviation.

Abstract: The general Facility Layout Problem deals with the arrangement of machines within the facility based on the constraints such as material flow distance, volume of flow of products, material handling cost and operation sequence of product. The facility layout problem is directly linked with the efficiency of the facility or the manufacturing line. The objective of this project is to design a simulation based methodology experiment on designing an optimized facility layout and evaluating the proposed alternative layouts using ARENA simulation. This project is conducted at Benteng Motor Sdn. Bhd. in Kota Kinabalu, Sabah. Currently, the company is planning to expand their manufacturing plant and hence the company needs an optimized facility layout to maximize the product capacity and manufacturing throughput time on a minimum utilization of resources environment. An eight steps simulation methodology is being proposed to design an optimized facility layout. A manufacturing re-engineering scenario has been developed to improve the existing system. The proposed scenario was evaluated using Arena simulation student package. The scenario has significantly increases the production capacity up to 225%, decrease the manufacturing throughput time by 19% as well as increase the utilization of majority of the manufacturing resources more than 200%.