Imtiaz Ahmed Choudhury

Application of Taguchi method in the optimization of end milling parameters

Abstract This paper outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in end milling when machining hardened steel AISI H13 with TiN coated P10 carbide insert tool under semi-finishing and finishing conditions of high speed cutting. The milling parameters evaluated are cutting speed, feed rate and depth of cut. An orthogonal array, signal-to-noise (S/N) ratio and Pareto analysis of variance (ANOVA) are employed to analyze the effect of these milling parameters. The analysis of the result shows that the optimal combination for low resultant cutting force and good surface finish are high cutting speed, low feed rate and low depth of cut. Using Taguchi method for design of experiment (DOE), other significant effects such as the interaction among milling parameters are also investigated. The study shows that the Taguchi method is suitable to solve the stated problem with minimum number of trials as compared with a full factorial design.

Machinability of nickel-base super alloys: a general review

Abstract Nickel-base super alloys (Inconel) are generally known to be one of the most difficult materials to machine because of their high hardness, high strength at high temperature, affinity to react with the tool materials, and low thermal diffusivity. This paper presents a general review of their material characteristics and properties together with their machinability assessment when using different cutting tools. The advantages and disadvantages of different tool materials with regard to the machining Inconel are highlighted.

Surface Roughness Prediction in the Turning of High-Strength Steel by Factorial Design of Experiments

Abstract This paper discusses the development of surface roughness prediction models for turning EN 24T steel (290 BHN) utilising response surface methodology. A factorial design technique has been used to study the effects of the main cutting parameters such as cutting speed, feed, and depth of cut, on surface roughness. The tests have been carried out using uncoated carbide inserts without any cutting fluid. A first-order prediction model within the speed range of 36–117 m min −1 and a second-order model covering the speed range of 28–150 m min −1 have been presented. The results reveal that response surface methodology combined with factorial design of experiments is a better alternative to the traditional one-variable-at-a-time approach for studying the effects of cutting variables on responses such as surface roughness and tool life. This significantly reduces the total number of experiments required.

Theory of energy efficiency standards and labels

Abstract Interests in establishing appliance standards are spreading from North America and Europe to many other countries around the world. Household appliance standards have more than three decades of history, but it became popular just after the oil price shock in the 1970s. Despite that, the literature on theory and methodology of developing energy efficiency standards is still limited. The theory and methodology of appliances efficiency programs are still being developed, and therefore, no single methodology is available for establishing standards and labels. The best approach may differ with goals, appliance type and local conditions. This paper discusses the theory and methodology involved in developing energy efficiency standards and labels for household appliances. It can be used also for other appliances with a few modifications. The initial step of setting a standard is proposing a test procedure followed by proposing suitable standards, labels and incentive programs for the appliances. The equations to calculate energy savings and the economic and environmental impact of standards and labels are also proposed. The theory and methodology presented in this study is suitable for a developing country that has a lack of available data and for a country that is considering revising existing standards and labels without major modification. Using this approach may shorten the time required for developing standards and labels compared with existing theory and procedure.

Tool-life prediction model by design of experiments for turning high strength steel (290 BHN)

Abstract This paper presents a study for the development of first- and second-order tool-life models at 95% confidence level for turning high strength steel. The tool-life models are developed in terms of cutting speed, feed rate, and depth of cut, using response surface methodology and design of experiment. The effects of the main cutting variables (cutting speed, feed, and depth of cut) on tool life have been investigated by the application of the factorial design method. All of the cutting tests were performed using uncoated carbide tools under dry conditions. Tool-life contours have been generated from these model equations and are shown in different plots. Dual-response contours of metal removal rate and tool life are shown also. The results are presented in terms of mean values and confidence levels.

Plastics and their machining: A review

Abstract Many different families of plastics are used in industry. The demand for the machining of plastics has recently increased. In most cases, traditional metal machining techniques and tools are being used in the machining of plastics. The present paper reviews the conventional mechanical machining of plastics. The cutting phenomena as indicated by the types of chips formed under various cutting conditions, and the cutting forces for the single-edge cutting of two broad types of plastics are discussed. When drilling plastics, the type of chip produced, the torque, and the thrust are considered. A general idea about the milling of plastics is shown. The possibility of grinding thermosets and thermoplastics using an open grinding wheel is discussed with reference to bond type, grit type, grit size and porosity.

Role of ambient temperature, door opening, thermostat setting position and their combined effect on refrigerator-freezer energy consumption

Abstract Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening and thermostat setting position. Two frost free household refrigerator freezers of the same capacity were tested in the laboratory to determine the sensitivity of their energy consumption to various usage conditions. The experiments were conducted to investigate the effect of single variables, such as temperature, thermostat setting positions and door opening, and their combined effect on energy consumption. Our investigation reveals that room temperature has the higher effect on energy consumption, followed by door opening. Thermostat setting position has the lower effect on energy consumption. More detailed tests were performed under different room temperature, thermostat setting position and door opening conditions. With the experimental results, a first order mathematical model has been developed to investigate their combined effect on energy consumption. The test results are discussed and presented.

The applicability of ISO household refrigerator–freezer energy test specifications in Malaysia

ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appliances. This paper presents the possibility of introducing ISO household refrigerator–freezer test standards in Malaysia. An experiment was conducted to investigate the effect of room temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator–freezer. With the experimental data, a multiple regression equation is developed to investigate their combined effect. Finally, energy consumption according to the regression equation with optimum setting conditions is compared with ISO standard test conditions. Our comparison reveals that ISO refrigerator–freezer test standards are applicable with respect to Malaysian climatic conditions and usage patterns.

Potential electricity savings by implementing minimum energy efficiency standards for room air conditioners in Malaysia

As a result of the rapid economic growth in the past, the usage of residential electrical appliances for the last two decades has increased rapidly in Malaysia. Like other developing countries with hot and humid climates, Malaysia has been experiencing a dramatic increase in the number of air conditioners used, which will be higher in the future. In order to reduce energy consumption in the residential sector, the Malaysia Energy Center considered implementing minimum energy efficiency standards for room air conditioners sometime in the coming year. This paper attempts to predict the amount of energy saved in the residential sector by implementing minimum energy efficiency standards for room air conditioners. The calculations were made based on the growth of ownership data of air conditioners. The number of room air conditioners has increased from 13 251 units in 1970 to 253 399 in 1991, and will be about 1 511 276 in the year 2020. As such, efficiency improvement on this particular appliance will have a significant impact on the future electricity consumption in this country. Moreover, it has been found that the energy efficiency standards for room air conditioners are very favorable.

Projected electricity savings from implementing minimum energy efficiency standard for household refrigerators in Malaysia

The Malaysian economy has grown rapidly in the last two decades. This growth has increased the ownership of household electrical appliances, especially refrigerator-freezers. Almost every house in Malaysia owns a refrigerator-freezer. The Malaysia Energy Center considered implementing a minimum energy efficiency standard for household refrigerator-freezers sometime in the coming year. This paper attempts to predict the amount of energy savings in the residential sector by implementing a minimum energy efficiency standard for household refrigerator-freezers. The calculations are based on the growth of refrigerator-freezer ownership data in Malaysian households. By implementing the programs in 2004, about 8722 GWh will be saved in the year 2013. Therefore, efficiency improvement of this appliance will provide a significant impact in future electricity consumption in Malaysia.