Dissertations/Theses - Department of Industrial and Production Engineering
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Item Mathematical modeling of cutting force and temperature distribution in turning steel under high-pressure coolant condition(Department of Industrial and Production Engineering, BUET, 2007-04-16) Bashirul Khoda, A. K. M.; Dhar, Dr. Nikhil RanjanFor abstracts please see full textItem Effects of cutting fluids on the machining of hardened AISI 4320 steel(Department of Industrial and Production Engineering, BUET, 2009-06-10) Maisha Tabassum; Dhar, Dr. Nikhil RanjanHard turning is a profItable alternative hl finish grinding in respect of dimensional accuracy and surface finish to fulfill functional requirement. improved perfonnance and prolonged service life llf the product. Hard turning is able to reduce processing time, production cost, ,urfacc roughness and ~elUptime appreciably in comparlson to grinding. But high heat generation at high production machining increase tool wear and deteriorates the job quality. The conventional cutting fluids are not that effeetlve in such situation. Minimum quantity lubrication (MQL) is a suitable alt~'l"natlvein thi. regard, In thi, research work, the effects of MQL on cutting perfonnance of hardened AISl4320 steel in respect of chip f<,nnalion, chip-tool interface lemperarure, tool "ear and produel quality have been ~tudicd using coated carbide insert (SNMG-TN 4000). Three types of culling fluids (soluble oil, vegetable oil and VO 68 cutting oil) have been used to compare the relative performance of th'l'>e culling fluids with each olher as well as with that of dry condition, Compared to dry condition, MQL performed better mainly due to substantial reduction in culling temperature that enabling favorable chip-tool int~'l"actlon.This also facj]jtated the substantial reduction in tmll "ear. dimensional inaccumcy and surface roughness. The result:>indicatcd that the u,e of minimum quantity lubrication (MQL) by VG 68 cutting oil pcrformed better in comparison to other cutting fluids in respect of chips formation mode. culling temperature, to"l wear, surface roughness and dimcnslonal devialion,Item Performance of coated carbide tools for high speed machining of hardened steel under high pressure coolant condition(Department of Industrial and Production Engineering, BUET, 2009-10) Dey, Samrat Kumar; Dhar, Dr. Nikhil RanjanA dillieull-to-eut material like hardened ~tccl i~ used predominantly in the automotive and !>caring industries due t,) its exceptional ~-orrosi"n ami thcrmal re~istanee and high shear strength. Ahnls;ve maLhining processes such as grinding have lypically heen required to machine hardened steels, hut advances in machine tools and cutting materials have allowed hard turning '.m modern lathes to become a realistic replacement for many grinding applications. De:;pite so many advantages, implementation of hard turning remains relatively low, primarily due tn concerns about the quality of hard turned surfaces and a lack of understanding about the wear behavior of cutling took In general, the most important point in machining proccsses is the productivity, achieved by cutting the highest amount of material in the shortest possible time using t()l)ls with the longest lifetime. Combining all the parameters involved in the machining process to maximize productivity is, nevertheless, a very complex ta~k and becomes much more difficult when working at high speed machining in hardened steels. To address thi~ concern, this research investigated the ellcet:; of cbanging pmcess conditions on wear behavior when turning harden~-dmedium carbon steel (56 HRC') with coaLedcarbide cutting tools. The aim of this resean:h is to investigate the influence of fccd rate and cutting speed on the wear behavior of both ShlMG and SNMM coated carbide inserts under high pressure coolant condition. Invc>;tigation on the effC(;t of high pressure coolant on the machined chip, culling tcmpcmturc, cutting force~ alld product quality is the prime intention of this rcsC'Item Effects of high pressure coolant on machinability of steels(Department of Industrial and Production Engineering, BUET, 2009-12) Kamruzzaman, Md.; Dhar, Dr. Nikhil RanjanI-ligh production machining aLhigil culling speed and iCed rate generates lurge heat and high culling lemperature. which shortens the tool life and deteriorate, tile job qllality. Thi" problem becomes more aelile wh~n thcjob; nrc difficllh to macbin~ and arc to be lIsed under Jynamic loadillg. The conventional culling fluids nrc not that effcctive in ,uch high production machining parlicularly in continuous cultlng of mutcrials Iikc stcels. Further lhe convcntional culling fluids ure nol ~nvironll1entally friendly. The di,po~al of lhc culling tluid; oli.cn lead; LOlocal water pollution and soil contaminution. Recycling and rcu,e of convcntional cutting l1uids also lcad to otbcr problem,. M~cbining of sof\. ,t,cky ~lld dllctil~ l1l~lC";"I,yidd, long conllllUOUScbips and rapid tool wear due 10 inctrLcLcnl action of lh~ CUllingl1uisure coolant ;ystem increa,ed tool life by 30% to 75% whcn turning C-60 steel by SNMG in;CI't and 80% to 140% when machining by SNMM insert, Tile suri'ace qU"lity of the machined ,urfa~e imprQvcd po"ibly duc to 1e1o,crdumage of the C11(!ingtool no,e. In ordcr to implemcnt the high-pressure cQo[ant machining technology, an analyticalmodd for cutting temperature has been developed. It is fmmd that ac~orJing to the ,elccted cutting condilions in the model-bascd comparisons, the prcdicted cutting tcmperalllrc under high pressure coolant conditions is rcduccd as higb as about 18% eomp~red with tho"~ in dJ)' culling.Item Cutting temperature force and roughness in high pressure coolant assisted hard turning(Department of Industrial and Production Engineering, BUET, 2008-10) Akhtar Hossain, Md.; Nikhil Ranjan Dhar, Dr.Machining hardened steels has become un important manufacturing process, particularly in the automotive and bearing industries. Abrasive processes such as grinding have typically been required to machine hardened steels, but advances in machine tools and cl1tling materials have allowed hard turning on modem lathes to become a realistic replacement for many grinding applications. There are many advantages of hard turning, such as increased flexibility, decreased cycle times, reductions in machine tool cost,.>,und elimination of environmentally hazardous cutting fluids. Despite these advantages, implementation of hard turning remains relatively low, primarily due to concerns about the quality of hard turned surfaces and a lack of understanding about the wear behavior of cutting tools. The effects of high pressure coolant on cutting performances in respect of chip formation, cutting temperature, cutting forces and surfa<,;erouglmess have been studied using carbide insert. The same experiments were earried out on the above under dry condition in order to compare the results with those obtained under minimal clJtling fluid condition. The result indicated that the machining with high pressure coolant performed much better than dry machining mainly due to substantial reduction in cutting tcmperature enabling favorable chip-tool interaction. This also facilitated the reduction in cutting forees and surface finish.Item Optimization of pressure and flow rate in HPC jet assisted turning of steel(Department of Industrial and Production Engineering, BUET, 2008-10) Moinul Hassan Chowdhury, Md.; Nikhil Ranjan Dhar, Dr.Although MRR increases with increase in velocities and feed rates but it raises tempcrarurc remarkably and such high cutting temperature adversely affects, directly or indirectly, chip fonnation, cutting forces, tool life, dimensional accuracy and surface integrity of the products. IWC (high pressure coolant) jet assisted turning is an effective method of machining, which allows overcoming the problems presented in the conventional turning of steels. The application of culting fluid with HPC leclmique causes a hydrItem Effect of high pressure coolant jet on temperature, chip and cutting forces in turning stainless steel by coated carbide insert(Department of Industrial and Production Engineering, BUET, 2008-02) Shah Alam, Mohammad; Nikhil Ranjan Dhar, Dr.High production machining, inhcrenlly generates large amount of heat leads to high culling zone temperature for its higher ~ulting vdocity, feed and depth of cut. Such hi gil ell Lling \cmp",alllfc if not reduced impairs surface integrity of th.o product arid reduce dimeMional accuracy as well as tool life. Conventional cutting fluid can not maintain (his silllutjOl1 properl}'_ Though in lower velocity a smnll amount of [luld enter in to the llllcrtoce lor its capillary action bllt in higher \'clo~ily it is nol evident. As cutting !luid can not r~ach into the chip-lOO! and work-tool inlerface due to low pressure and low boiling temperature, it cannot effectively lubricate and cool the tool and job. Low boiling temperatme cause vapori7alion of cutting fluid and prevent it to enter into cutting interface making a harrier to flow, High-pn:ssuTC coolant (HPC) jd is an effective alternative to reduce temperature anti tool wear. HPC jet applied diagonally to thc in5ert~ cutting edgc remOves heat and reduce tool wear and also provide better lubrication in the lool tip and culliL1~int~rf"ce. Keeping these in view, obje~live of the present work is to m'lk~ an experimental investigation on the role of high pressure cool ing jet in tuming stainless steeL