Papers by Keyword: Burr Formation

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Authors: János Kodácsy, András Szabó
Abstract: Remained burrs on edges of the parts after metal cutting operations may cause many problems in the production process and in the quality of products, therefore the burrs must be completely removed. In the paper, the authors give an outline of the elements and the technical and economical influences of the burr formation, and the characteristics of the burrs and the burr formation mechanisms. The authors present some special processes that are suitable for deburring of small pieces (e.g. Magnetic Abrasive Deburring), and a frequently applied mechanical process: power brushing. The authors have carried out many investigations regarding the magnetic abrasive deburring of small, blanked sheet metal parts, furthermore the machine deburring of large-sized metal workpieces by carbide-reinforced cylindrical brushes. The detailed conditions, data, results and conclusions of these deburring experiments are treated in the paper too.
235
Authors: Vincent Aizebeoje Balogun, Edem Friday Isuamfon, B. Otanocha Omonigho
Abstract: The energy consumption and machinability index of metallic alloys are very important in determining the economic and environmental value of manufacturing process. Various machinability problems with Nitronic 33 steel alloy have been reported in literature. These problems have been attributed to the work hardening of the material during machining operation and hence greatly influences and contributes to the green house gas emission. In this work, the chip and burr formation during the machining of Nitronic 33 steel alloy was investigated in other to optimize the cutting parameters and provide a knowledge base for machinists when machining austenitic stainless steels. The result shows that although continuous chips were formed throughout the machining tests, an evidence of continuous chip with built-up edges was also observed. This phenomenon tends to initiate the formation of discontinuous chips especially at high pressure coolant flow of 7 and 9.7 MPa. It is concluded that conventional cutting environment at 90 m/min cutting velocity is the optimum process parameter most suitable for machining Nitronic 33 steel alloy. The research outcome will address some of the problems encountered during high speed machining of Nitronic 33 steel alloy and the general understanding of the machinability of this alloy.
125
Authors: Da Peng Dong, Xiao Hu Zheng, Ming Chen, Qing Long An
Abstract: In recent years, with the development of machinery industry, micro-cutting technologies have been gradually moving into engineering realization. The paper carries out a series of works on simulation modeling of micro-cutting of Ti-5Al-5V-5Mo-3Cr considering tool edge radius. Unlike conventional cutting, in micro-cutting the effect of tool edge radius which has a marked impact on cutting force, specific cutting energy, burr formation and burr size can no longer be neglected.
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Authors: Wen Jun Deng, Wei Xia, Long Sheng Lu, Yong Tang
Abstract: 2D finite element model with the same material for backup to minimize the burr size was developed to investigate mechanism of burr formation and burr minimization. The flowstress of the workpiece and backup material are taken as a function of strain, strain-rate and temperature. Temperature-dependent material properties are also considered. The Cockroft-Latham damage criterion has been adopted to simulate ductile fracture. The crack initiation and propagation is simulated by deleting the mesh element. The result shows putting a backup material behind the edge of the workpiece is an effective way to minimize the burr size. The effects of cutting condition, temperature and different backup material properties on the burr formation and burr size can be investigated using the developed finite element model. This model could be useful in the search for optimal tool geometry and cutting condition for burr minimization and for the modeling of a burr formation mechanism.
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Authors: Wen Jun Deng, C. Li, Wei Xia, X.Z. Wei
Abstract: A coupled thermo-mechanical model of plane-strain orthogonal metal cutting including burr formation is presented using the commercial finite element code. A simulation procedure based on Normalized Cockroft-Latham damage criterion is proposed for the purpose of better understanding the burr formation mechanism and obtaining a quantitative analysis of burrs at exit. The cutting process is simulated from the transient initial chip formation state to the steady-state of cutting, and then to tool exit transient chip flow, by incrementally advancing the cutting tool. The effects of cutting condition on the non-steady-state chip flow while tool exit can be investigated using the developed finite element model.
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Authors: Mustafa Bakkal, Veli Nakşiler, Bora Derin
Abstract: In this study, machinability of Zr-based bulk metallic glass (Zr52.5Ti5Cu17.9Ni14.6Al10) (BMG) material was investigated by conducting a set of milling and drilling experiments. In milling, two different tool paths, spiral and slot milling, were used. To investigate the behavior of BMG in drilling by two different tools at different feed rates, two sets of drilling experiments are conducted. Crown shaped exit burr formation are observed in drilling of BMG. Best results on thrust force, exit burr formation and hole surface roughness is obtained while using micrograin WC tool on BMG drilling. No chip light emission was observed during all tests. This study concludes that BMG can be achieved machining with good surface roughness, (Ra=0.113 µm), using conventional cutting tools.
335
Authors: Sung Han Rhim, Seung Wook Baek, Soo Ik Oh
Abstract: In low temperature co-fired ceramic (LTCC) packaging which offers a good performance to produce multilayer structures with electronic circuits and components, the via-hole fabrication of LTCC ceramic-PET double layer sheets (green sheets or green tapes) by micro-scale punching plays an important role in providing an electric path for the interconnection between layers. Although conventional punching has been used widely and many researchers have provided useful insights of the process, they are restricted to the punching of single layer material. This paper discusses the characteristic of micro via-hole punching of double layer sheets and the optimum process condition for via-holes of good quality. Workpiece (double layer sheet) used in the present investigation consists of LTCC ceramic composite material layer (ceramic layer) of 20~100*m in thickness and PET layer of 38 and 75*m in thickness by tape-casting. The diameter of via-holes ranges from 100~300*m.
509
Authors: Juan Zhang
Abstract: Numerical simulation of the blanking process of a sheet metal, i.e. the formation of roll-over and a burnished surface, and crack initiation and propagation, is done using an elastic plastic finite element model. The Normalized Cockcroft and Latham’s expression is used as a ductile fracture criterion. Numerical study was conducted to investigate how the tool-wear affects the burr height by varying the punch nose radius. The simulation results obtained under the effect of the same process variables are in good agreement with the experimental results. Six punches with various nose edges, 0.00mm, 0.05mm, 0.10mm, 0.20mm, 0.30mm and 0.40mm were used for blanking simulations. The results indicate that the burr height is directly proportional to the punch nose radius.
95
Authors: Mohammad Yeakub Ali, Mohd Aliff Omar, Khairul Irman Othman, Wayne N.P. Hung
Abstract: This paper discusses burr formation in micromilling of AISI 304 stainless steel. Chip load, cutting speed and the application of coolant were chosen as the milling parameters. Experiments were conducted using 500 µm diameter tungsten carbide end milling tool. Milling parameters and measured burr height values were analyzed and statistical models were developed for the estimation of burr height. The models showed that the chip load and cutting speed both have direct and interactive contribution to burr formation. When micromachining without coolant, the burr height increases about 40% compared to that of machining with coolant. The optimized values of chip load and cutting speed were found to be 1 µm/tooth and 78 mms-1 respectively. The predicted burr heights were 5-7% larger than that of measured values.
247
Authors: Takashi Kito, Ryutaro Tanaka, Akira Hosokawa, Takashi Ueda, Tatsuaki Furumoto
Abstract: . Burr is formed at workpiece edge in most metal cutting process. These burrs make troubles on production lines in terms of added cost and time for deburring process. The purpose of this study is to investigate the influence of workpiece hardening on the burr formation in face milling of carbon steel AISI 1045. Before machining, laser hardening by CO2 laser is irradiated on the side face along the line where burr is expected to be formed. The laser irradiated area of carbon steel has high hardness and brittle characteristic in comparison with mother phase. In case of machining laser hardened workpiece, the burr height was smaller compared with standard steel. By controlling laser irradiation conditions, burr is not observed so that the chipping (negative burr) like chamfering is caused. From these results, it was clarified that laser hardening is effective to prevent burr formation and this technique can be applied to high efficiency processing.
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