Effect Of Tool Geometry And Nose Profile Micro-Deviation On Surface Roughness In Finish Turning

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

A Study of Weld Seams on Low Carbon Steel ABS Grade a Marine Plates Using SMAW Process

The research aims to study and assess the impact of weld seams of low carbon steel ABS Grade A marine plates of 12.7mm thick using manual SMAW process as per AWS D1.1 structural welding code requirements and fulfilments of ASME Section IX pressurized equipment welding code requirements too. Different voltages, currents, and travel speeds were used to weld the test specimen plates. After the manual SMAW process, a series of testing techniques, including non-destructive tests, such as VT and RT, and destructive tests, such as tensile tests, bend tests, impact tests, microhardness tests, and metallographic examination has been conducted to assess/evaluate on the welded seam profiles and analyses/determines whether the accepted welded seam profiles have fulfilled the relevant welding code requirements. From the series of assessments and analyses, it is confirmed that the welded test specimen 1 having the welding parameters (i.e., voltage 23 V, current 70 A, and travel speeds 56.52 – 312.50 mm/min, having a range of heat inputs from 0.31kJ/mm to 1.71kJ/mm) is accepted as the quality good weld seam

Displacement rate effects on mixed-mode I/II delamination of laminated carbon/epoxy composites

Mixed-mode delamination is one of the common failures of composites which has not been studied under low-impact loading. This paper studies the influence of displacement rate on mixed-mode I/II delamination of unidirectional carbon/epoxy composites. Single leg bending test is performed at displacement rates of 1, 10, 100, and 500 mm/min. Experimental results reveal that the mixed-mode I/II fracture toughness is invariant with the displacement rate. In addition, scanning electron micrographs shows that shear cusps are more obvious at 1, 10, and 100 mm/min. At 500 mm/min, significant matrix debris is noticed. Furthermore, the proposed three-dimensional rate-dependent fracture criterion is found to well predict the fracture toughness. Numerical simulation using cohesive zone model suggests that the lower numerical peak load is due to lower damage dissipated energy. In addition, the theoretical and numerical traction-separation responses show significant differences, which is also reflected in the numerical phase angle. This implies that the local mixed-mode ratio is not constant throughout the simulation process

Prediction of tool wear using machine vision approach

Tool wear prediction plays a crucial role in the machining industry for proper planning and optimization of cutting conditions. Nevertheless, tool wear assessment method using sensor signals has its drawbacks in the industry application. The objective of this study is to apply Artificial Neural Network (ANN) prediction model and machine vision system to predict flank wear in turning operation based on the texture images of machined surface captured by complementary metal oxide semiconductor (CMOS) camera in-cycle. The image pre-processing technique was utilized to enhance the quality of surface texture images acquired from the experiment and the texture descriptors were extracted from the processed images using gray-level co-occurrence matrix (GLCM). Three ANN prediction models with different input variables were developed using MATLAB software. The findings showed that the ANN prediction model with input variables of contrast, entropy, cutting speed, and feed rate outperformed the other ANN prediction model. The prediction accuracy of this model in estimating flank wear reached up to 93.18%. A very good fit and the relationship could be found in this model with R2 of 0.9863 for flank wear

Oil palm suitability assessment in the northern region of Sarawak using Geographic Information System and Fuzzy Analytic Hierarchy Process approach

Oil palm plantation in Malaysia has been developed on a vast scale due to the tremendous need for crude palm oil. However, the accelerated development of oil palm plantations produced predicaments, such as monoculture cultivation, water quality deterioration, and loss of creatures' habitats to Malaysia, including Sarawak. The Sarawak government has appointed 2 million hectares of state's land for oil palm plantation, of which 1.2 million hectares have already been established. However, oil palm suitability assessment is lacking in Sarawak. Hence, it is important to assess oil palm plantation's suitability in an area with the likelihood of further expanding for oil palm plantation in Sarawak. The suitability assessment is aimed to promote the oil palm industry's sustainability. The research aims to conduct a land-use suitability assessment in a region with established oil palm plantations around Kabuloh, Miri, the Sarawak's Northern Region. A Geographic Information System was implemented to evaluate the suitability of oil palm cultivation in the study area. The assessment result showed that 78% of the study area is suitable for oil palm plantations. The developed oil palm suitability map could be utilized as a decision support tool to develop comprehensive planning for future oil palm expansion

Displacement rate effects on mixed-mode I/II delamination of laminated carbon/epoxy composites

Mixed-mode delamination is one of the common failures of composites which has not been studied under low-impact loading. This paper studies the influence of displacement rate on mixed-mode I/II delamination of unidirectional carbon/epoxy composites. Single leg bending test is performed at displacement rates of 1, 10, 100, and 500 mm/min. Experimental results reveal that the mixed-mode I/II fracture toughness is invariant with the displacement rate. In addition, scanning electron micrographs shows that shear cusps are more obvious at 1, 10, and 100 mm/min. At 500 mm/min, significant matrix debris is noticed. Furthermore, the proposed three-dimensional rate-dependent fracture criterion is found to well predict the fracture toughness. Numerical simulation using cohesive zone model suggests that the lower numerical peak load is due to lower damage dissipated energy. In addition, the theoretical and numerical traction-separation responses show significant differences, which is also reflected in the numerical phase angle. This implies that the local mixed-mode ratio is not constant throughout the simulation process