Sung , Aun Naa (2015) Effect Of Tool Geometry And Nose Profile Micro-Deviation On Surface Roughness In Finish Turning. PhD thesis, Universiti Sains Malaysia.
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Abstract
Kekasaran permukaan bahan kerja dalam pelarikan penyudah ditentukan oleh kadar suapan serta profil tepi muncung mata alat pada tepi bersentuhan bagi mata alat dan bahan kerja. Geometri bagi profil tersebut dipengaruhi oleh geometri-geometri mata alat seperti jejari muncung mata alat, sudut sisi potong samping, sudut miring, sudut serpih dan sisihan profil muncung mata alat. Oleh itu, kajian ini bertujuan untuk mengkaji kesan geometri-geometri mata alat tersebut terhadap kekasaran permukaan bahan kerja dalam pelarikan penyudah. Model analisis baru Ra dan Rq dengan mengambil kira jejari muncung mata alat, sudut sisi potong samping dan kadar suapan dibangunkan. Kaedah simulasi bagi Rt, Ra dan Rq berasaskan profil muncung mata alat yang ideal (bentuk lengkok bulat) juga dibangunkan. Kaedah ini mengambil kira jejari muncung mata alat, sudut sisi potong samping, sudut miring, sudut serpih dan kadar suapan untuk mengkaji kesan gabungan sudut sisi potong samping, sudut miring dan sudut serpih terhadap kekasaran permukaan. Kaedah simulasi ini dilanjutkan dengan menggunakan muncung mata alat sebenar untuk mengambil kira sisihan profil muncung mata alat. Bagi mengambil kira kesan getaran gelatuk dan kehausan mata alat, isyarat getaran dan imej mata alat yang diperolehi daripada karbida haus turut dipertimbangkan dalam kaedah simulasi tersebut. Kaedah untuk memperolehi 95% selang ramalan kekasaran permukaan berasaskan data simulasi juga dibangunkan. Data yang diperolehi daripada model analisis yang dibangunkan agak menepati keputusan eksperimen jika berbanding dengan model-model analisis sedia ada yang hanya mengambil kira jejari muncung mata alat dan kadar suapan sahaja. Data Ra dan Rq yang diperoleh daripada kaedah simulasi berasaskan profil muncung mata alat yang ideal didapati menepati keputusan eksperimen berbanding dengan kedua-dua model analisis. Kesan sisihan profil muncung mata alat terhadap kekasaran permukaan adalah signifikan walaupun toleransi pada jejari muncung mata alat adalah dalam lingkungan 10% yang dibenarkan dalam piawaian ISO 3685. Sisihan profil muncung mata alat menyebabkan Rt, Ra dan Rq berbeza dengan nilai idealnya sebanyak 42%, 27% dan 29%. Berdasarkan selang ramalan kekasaran permukaan, 100% Rt, 96% Ra dan 96% Rq yang diperolehi daripada eksperimen adalah berada di dalam selang tersebut. Dengan menggunakan kaedah simulasi yang berasaskan profil mata alat sebenar, pengilang mata alat boleh mengawal kualiti mata alat. ________________________________________________________________________________________________________________________ The roughness of a machined surface in finish turning is determined mainly by the feed rate and nose edge profile of the cutting tool at the tool-workpiece interface. The geometry of the tool-workpiece interface, in turn, is determined by the tool geometries, such as nose radius, side cutting edge angle (SCEA), inclination angle, rake angle and as well as the nose profile micro-deviation. In this study, the effect of nose radius, SCEA, inclination angle, rake angle as well as the nose profile microdeviation on surface roughness of a finished workpiece was investigated. New analytical models for Ra and Rq by considering nose radius, SCEA and feed rate are proposed. A simulation method to generate Rt, Ra and Rq based on the ideal (circular) nose profile by considering the nose radius, SCEA, inclination angle, rake angle and feed rate is proposed. Using the simulation method, the combined effect of SCEA, inclination angle and rake angle on the surface roughness was investigated. The simulation method was extended by using the actual nose profile obtained from an image of the tool nose of a new cutting insert to include the effect of the nose profile micro-deviation on surface roughness. To study the nose profile micro-deviation by considering the effect of chatter vibration and nose wear on surface roughness, additional input data, namely the vibration signal and image of the worn insert, were considered in the simulation. A method to obtain the 95% roughness prediction interval based on the simulation data is also proposed. The roughness data obtained from the newly developed analytical models were found to agree more closely with the experimental data compared to those obtained from the existing analytical models that consider only nose radius and feed rate. The Ra and Rq data obtained from the simulation method based on the ideal nose profile showed the closest agreement with the experimental results compared to the new and existing analytical models. Comparison of the roughness data from the simulations based on the ideal nose profile and the actual nose profile showed the influence of the nose profile micro-deviation on the surface roughness. Although the nose radii of the tools are within the 10% tolerance allowed in the ISO3685 standard, from simulation the nose profile microdeviation caused Rt, Ra and Rq to deviate as much as 42%, 27% and 29% respectively. Based on the 95% roughness prediction interval it was found that 100%, 96% and 96% of the Rt, Ra and Rq values, respectively, obtained experimentally fell within the prediction interval. Using the proposed simulation method based on actual nose profile, tool manufacturer can monitor the quality of the tool nose based on the predicted surface roughness of the workpiece in finish turning.
| Item Type: | Thesis (PhD) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=3216 |
| Subjects: | T Technology T Technology > TJ Mechanical engineering and machinery > TJ1-1570 Mechanical engineering and machinery |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Mekanikal (School of Mechanical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 06 Sep 2018 09:23 |
| Last Modified: | 06 Sep 2018 09:23 |
| URI: | http://eprints.usm.my/id/eprint/41778 |
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