Dissertations/Theses - Department of Industrial and Production Engineering

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End date: 2009Subject: search.filters.subject.Machining processes

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    Effect of minimum quantity of lubricant (MQL) on tool wear and product quality in machining steel by coated carbide insert
    (Department of Industrial and Production Engineering, BUET, 2007-05) Shariful Islam, Md.; Dhar, Dr. Nikhil Ranjan
    The concepl of Minimum QU811tity Lubrication (Mal) sometimes referred to as near dl)' lubrication or micro lubrication has been advocated since a decade ago as a me8rlS of addressing the issue of environmer'llal troublesome. Minimum Quantity Lubrication mentions to the use of cutting fluid of only a Iiille amount usually of a flow rate of 50 to 500 ml/hour-which is about tllree to four orders of scale lower than the amount commonly used in flood cooling condition, lor example, up to 10 liters of fluid can be supplied per minute. Saving lubricant costs and tool Iworkplece/machine cleaning cycle time the minimization of cutting fluid also leads to economical benefits. A number of studies have showr'l that MQL machining can show saliSfactory performance in praclical machining operations. But, there has been lillie Investigation of the cutting fluids to be used in MQL machining. In this regard the proposed research work has been earned out with a view to study the effects of Minimum Quantity lubrication (MQl) by water soiuble cutting fluid on the cutting performance of medium carbon steei, as compared to completely dry and wet machining in terms of tool wear reduction, tooi iife increment and machined surface mtegrlty, Based on the procesS parameters (speeds, feeds and depth of cut) an approach has also been performed to recognize the apt MQL nozzle position for better coohng aellon, In the study, the minimum quantity iubrication will be provided with a spray of air and water soluble cutting fluid. Significant progress xii has been made In dry and semidry machining recently, and Minimum Quantity Lubrication (MQL) machining in particular has been accepted as a successful semi-dry application because of its environmentally friendly characteristics. " Compared to the dry or wet machining, MOL machining performed much better-quality, mainly due to considerable in cutting zone temperature enabling favorable chip formation and chip-tooi interaction, It also provides substantial reduction in tool wear, which augment the toci life, and surface finish. Moreover, it provides environment friendliness (maintaining neat, clean and dry working area and improves the machinability characteristics.
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    Analytical and experimental investigation of effects of high-pressure coolant on tool wear, tool life and surface roughness in turning steel
    (Department of Industrial and Production Engineering, BUET, 2007-04) Tanveer Ahmed, Md.; Dhar, Dr. Nikhil Ranjan
    Manufacturing quality products at a higher rate and low cost is the key to exist and sustain in the modem era of cut-throat competition. To do that, , machining is practised at extreme conditions. As part of this approach, high speed machining is adopted. However, high speed machining is inherently associated with generation of intense heat and cutting temperature at the cutting zone resulting increased tool wear and deterioration of machined surface. New methods are being explored to reduce the heal. Application of high-pressure coolant is perceived to be a superior choice in this regard. Technological beneficial effects of proper high-pressure coolant on machining already been established in number of previous investigations Surface roughness is a determinant of product quality and reduction of tool wear and consequent increase of toollne can reduce the machining cost .• However, estimation of these two machining performance parameters can contribute to manufacturing optimization and planning. Mathematicai models are instrumental to predict machining performance at different machining combinations, Response surface method is adopted to develop statistical models of tool life and surface roughness. Cutting speed and feed rate are the independent variables of the models. As part of this method, based on the experimental results of turning medium carbon steel statistically designed speed-feed combination by uncoated carbide insert using high-pressure coolant jet, regression analysis will be performed to determine the coefficients of the model followed by analysis of variance to check the adequacy of the model.The models are expected to quantify machining performance in terms oftoollife and surface roughness at various cutting speed and feed.
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    Effect of high pressure coolant jet (HPCJ) in drilling different steels
    (Department of Industrial and Production Engineering, BUET, 2006-09) Halimur Rashid, Md.; Nikhil Ranjan Dhar, Dr.
    High production machining, grinding and drilling inherently generates large amount of heat leads to high cutting zone temperature for its higher cutting velocity, feed and depth of cut Such high cutting temperature if not reduced impairs surface integrity of the product and reduce dimensional accuracy as well as tool life. Application of cutting fluids changes the performance of machining operations because of their lubrication, cooting, and chip flushing functions. However, the conventional cutting fluids are not that effective in such high production drilling. Low boiling temperature cause vaporization of cutting fluid and prevent it 10enler inlo cutting interface making a barrier to flow, In addition, flowing chips through drill flute prevent the fluid to enter into the cutting zone. Further, they (liso deteriorate the working environment and lead to general environmental pollution. High-pressure coolant presents itself as a viable alternative for drilling with respect to heat dissipation, roundness deviation and taper of the hole, chip formation mode and tool wear. This study compares the mechanical performance of high-pressure coolant to completely dry lubrication for the drilling of AISI-4340 steel and AISI-1040 steel based on experimental measurement of roundness deviation and taper of the hole, chip formation mode and tool wear, Results indicated that the use of high-pressure coolant leads to lower roundness deviation and taper of the hole, favorable chip-tool interaction and reduced tool wear.