Mohammad Ahsan Habib

Development of a Passive Damping Tool Holder for the Improvement of Surace Roughness in Turning Operation of Stainless Steel

One special type of passive damping setup has been used to investigate the surface responses with the variation of different process parameters. In this study, a special design capsule type tool holder has been used to investigate the process parameters effect in machining of stainless steel during turning operations under different cutting condition such as-RPM, feed, depth of cut. Inside the capsule high viscous fluid is used as damping materials and its effects has been investigated accordingly. The effect of damping during turning process is investigated by studying generated surface profile for both with and without damping system. It has been observed that surface roughness is better in the newly designed passive damping tool holder compared to normal cutting conditions.

Investigation of surface parameters during hot air streaming turning process of mild steel

Different types of coolant are widely used in different metal cutting processes to improve the machining responses. But the suitability of using the correct cutting fluid is very important considering the concept of green environment. In this study, hot air is used as an alternative approach for hot machining process and coolant. Hot air is considered to initially heat the work-piece for easy machining operation. In this study, two different velocities of hot air has been applied during the machining of mild steel in turning process and its effect is investigated in terms of surface roughness. With the variation of different process parameters, it has also been observed that surface roughness at different cutting conditions using hot air is improved significantly. A clear comparison has been made to investigate the responses of surface roughness at different cutting conditions in between the hot air and normal machining processes. This procedure may be used as an alternative approach in the dry cutting re...

Tool Life Improvement by Externally Applied Ultrasonic Waves in Cutting Process of Dry Turning Operation of Mild Steel

Tool wear is an inevitable impediment in machining processes. It is the gradual failure of cutting tools due to regular use. Tool wear affects productivity, dimensional accuracy thereby indirectly representing a significant portion of the machining costs. In this paper, a novel technique has been proposed and adopted with an aim to reduce tool wear. External ultrasonic sound waves were applied in the turning process of mild steel in an attempt to reduce the cutting tool vibration thereby leading to improvements in tool life. In this unique technique ultrasonic sound has been applied from the both sides of the tool holder in the cutting process as waves to reduce tool vibrations and improvement of chip behavior at a certain optimized frequency. Experiments were carried out at 60 KHz ultrasonic frequency to determine the tool wear to the best degree possible. To investigate the cause of ultrasonic effects on tool wear, cutting tool vibration and chip morphology were also studied. The experimental results showed significant improvements in tool wear, vibration and chip behavior.

Investigation of Quality of Drilled Holes by Guiding the Drill Bit Using Permanent Magnet on a Glass Fibre Reinforced Polymer Composite Material

The use of glass fibre reinforced polymer composite materials (GFRP) increases due to its superior properties that draw the attention of the other researches focusing on relevant aspects concerning the machining of such materials. In conventional machining for hole creation, drilling is the most frequently employed machining process for hole generation in fibre reinforced materials. Due to the laminated structure of the composite materials, several types of damages and other surface irregularities are introduced during drilling processes. These defects in the holes lead to about 60% of the rejections in assembly plant. Surface roughness has been identified to be the main contribution for defects in holes machined in composites. These defects would create reduction in structural stiffness, which may lead to variation of dynamic performance of the whole structure. Hence, achieving the desired hole quality is of great importance for the functional behaviour of the mechanical parts. In the present work, the effect of permanent magnet on the quality of drilled holes on GFRP composite is presented. Experiments are performed under different magnetic drilling conditions of spindle speed, feed rate and drill diameter on CNC drilling machine using three levels of factors. A procedure has been adopted to assess and optimize the chosen factors by the use of Box Behnken design to analyse the effects of different parameters. From the experimental results, it has been observed that the technique used is convenient to predict the main effects and their interaction effects of different influential combinations of machining parameters on surface roughness. It has been found that effect of permanent magnetic on the guiding mechanism of the drill bit which lead to get improved surface roughness with better circularity compared to normal drilling processes. A mathematical model has been developed for the prediction of surface roughness using permanent magnet and normal drilling processes.

3D CFD Based Optimization Technique for Muffler Design of a Motorcycle

In order to minimize the sound transmission due to exhaust gases, the most common and important part of the engine system is muffler. A back pressure on engine is always produce due to the use of the exhaust muffler. This back pressure represents the extra static pressure exerted by the muffler on the engine through the restriction in flow of exhaust gases. The back pressure mainly depends on the internal shape and overall design of the exhaust muffler. Design of muffler is a complex function that affects noise characteristics, emission and fuel efficiency of engine. In this study, a combine model of response surface methodology (RSM) and desirability analysis is used for optimizing the back pressure of a motorcycle reactive muffler, in order to improve the performance of the muffler. For this optimization process, the design variable parameters are size of perforation, number of perforation and chamber size. To measure the back pressure 3D CFD based CAE software has been used. Prediction of acoustics transmission loss virtually is an important analysis required for the development of muffler at an initial design stage. For this reason, for the optimized design virtual acoustics transmission loss analysis is conducted. It is found that after optimizing the design of the muffler, the back pressure is decreased and the acoustics transmission loss is increased that can ensure the improvement of the muffler efficiency.