Papers by Keyword: Carbide Insert

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Authors: K. Kadirgama, M.M. Noor, K.A. Abou-El-Hossein, B. Mohammad, H.H. Habeeb
Abstract: In this study the performances of some commercially available carbide inserts when machining Hastelloy C-22HS was investigated under scanning electron microscopy (SEM) for wear mechanisms and other microstructure defects. Carbide inserts coated with TiCN/TiN and TiALN/ TiN experienced severe intergranular fractures and cracks. High temperature causes the layer of the coating to wear off and subsequently the inserts damaged at fast rates. Both types of inserts suffered from high crater wear and thermal cracking. Most of the wear occurred at the nose and flank of the inserts. Generally, it was observed that carbide coated with TiALN/ TiN cutting tool performed better than carbide coated TiCN/TiN cutting tool when milling Hastelloy C-22HS
295
Authors: A.K.M. Nurul Amin, A.A. Che Omar, M.A.Mohammed Kamal, Mahmoud M.A. Nassar, N.F. Mohd Zaib, Muammer Din Arif
Abstract: Soda lime glass is used extensively in camera lens, micro gas turbines, light bulbs, tablewares, optics, and chemical apparatus owing to its high hardness, excellent optical properties, and good corrosion and chemical resistance. Such applications of soda lime glass demand high machining and finishing precision. On the other hand, machining of glass poses significant challenges due to its inherent brittleness. The process of removal of material from glass, if not done in ductile mode, can generate subsurface cracks and brittle fractures which have adverse effects on its functionality. This research investigates the high speed micro-end milling of soda lime glass in order to obtain ductile regime machining. It has been found by other researchers that ductile mode machining can avoid sub-surface cracks and brittle fractures. However, in ductile mode machining, the gummy chips settle permanently on the machined surface affecting adversely the surface finish. In order to avoid such chip settlement, compressed air was directed using a special air delivery nozzle to blow away the resultant gummy chips, thereby preventing them from settling on the machined surface. Response surface methodology (RSM) and a commercial NC end mill were used to design and perform the machining runs, respectively. Machining was done using: high spindle speeds from 30,000 to 50,000 rpm, feed rates from 5 to 15 mm/min, and depth of cuts from 3 to 7 μm. Three different diameter carbide tools were used: 0.5, 1, and 2 mm. A surface profilometer was used to analyze the surface roughness of the resultant machined surface. Subsequently, the data was used for finding the best combination of cutting parameters required to obtain the lowest surface roughness. The results demonstrate that high speed machining is a viable option for obtaining ductile regime machining and generating machined surfaces with very low surface roughness in the range of 0.08μm – 0.22 μm, using 0.5 mm carbide end mill cutter.
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Authors: M. Subha Shree, M. Vijaya Ganesa Velan, M. Padmakumar
Abstract: Providing sufficient provisions to transfer heat from the work-tool interface is a key to improve tool life and surface integrity. With the conventional flood cooling system where the coolant is directed towards the work-tool interface at very low pressure, there are possibilities for the coolant to get heated up and produce vapors which in turn insulates the cutting zone from the coolant. This reduces the purpose of coolant. Supplying coolant at very high pressure and very high velocity may provide the best control to reduce cutting temperature and tool wear and correspondingly increases tool life. This paper deals with an experimental investigation on the effect of high pressure coolant on surface finish in cylindrical turning of AISI 1060 Steel using tungsten carbide turning insert. Surface Roughness values are captured with different cutting speed and feed rates with high pressure and low pressure coolant supply. It is observed that there was a considerable improvement in surface finish with the use of high-pressure coolant (HPC) under various cutting speed and feed rate.
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Authors: Rozmarína Dubovská, Jozef Majerik, Henrieta Chochlikova
Abstract: The main aim of the authors research is to assess the investigation of durability T = f (vc) in turning of the AISI 304 austenitic stainless steel with the CNMG 120408 coated carbide cutting insert. Experimental tests of selected material were realized in the CNC machine tool Doosan Puma 240 with Fanuc 21i TB control system. This experimental study is a continuation of the solutions of grant VEGA no. 1/9428/02 titled “The technological heredity of the machined surfaces - surface integrity”. The aim of the present paper is to focus scientific research on the impact of the various applied values of cutting speeds in the outer longitudinal turning. This paper, together with the achieved results is a basis that will optimize the performance of turning process of the austenitic stainless steel AISI 304 used for special applications with their dominant functional areas.
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Authors: Gusri Akhyar Ibrahim, Che Hassan Che Haron, Jaharah A. Ghani
Abstract: Wear mechanism on the flank of a cutting tool is caused by friction between newly machined surface and the cutting tool, which plays predominant role in determining tool life. Detailed study on wear mechanism at the cutting edge of carbide tools were carried out at cutting speed of 55 – 95 m/min, feed rate of 0.15 – 0.35 mm/rev and depth of cut of 0.10 – 0.20 mm. The wear on the cutting tools was occurred predominantly on the nose radius, as effect of lower feedrate and nose radius selected. Various wear observed on both coated and uncoated cutting tool such as abrasive wear, adhesive wear, adhering chip on the cutting edge, flaking, chipping, coating delamination of coated tool, crack and fracture. The abrasive wear predominantly occurred on the flank face while the flaking on the rake face. Abrasive wear occurred at nose radius due to the depth of cut selected was low therefore, the contact area between the cutting tool and the workpiece material was small. Adhesion or welded titanium alloy onto the flank and rake faces demonstrated a strong bond at the workpiece-tool interface. The adhesion wear takes place after the coating has worn out or coating delamination has been occurred. The crack occurred possibly due to machining at high cutting speed and high depth of cut. Cutting at high cutting speed caused more heat generated at the cutting edge and at high depth of cut caused more cutting forces on the insert.
195
Authors: Qiu Lin Niu, X.J. Cai, Zhi Qiang Liu, Ming Chen, Qing Long An
Abstract: As a typical high strength material, titanium alloy Ti-6Al-2Sn-4Zr- 2Mo-0.1Si (TA19) is used to manufacturing the compressor power-brake of aircraft engine and the aircraft skin. All the machining experiments were carried out on a CNC-milling center under the stable conditions of cutting speed, feed rate, and depth of cut. The performance and wear mechanisms of coated- and uncoated carbide tools have been investigated in this paper to evaluate the machinability of TA19 in face milling. The three tools used were PVD-TiN+TiAlN, CVD-TiN+Al2O3+TiCN and uncoated carbide inserts. The results indicated that PVD coating had the best performance than other tool materials in milling titanium alloy TA19, and the cutting force and the wear value were the smallest than that for CVD-coated and uncoated tools. The failure types of PVD-, CVD- and uncoated inserts were the crater wear and micro tipping; the crater wear and tipping; tipping. Abrasive wear and adherent wear were the predominant mechanism of PVD-TiN+TiAlN carbide insert in face milling TA19 alloy. For CVD- and uncoated carbide, adherent wear was predominant.
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