Showing papers by "Taylan Altan published in 2001"
TL;DR: In this article, the authors summarized a technological review of the hydroforming process from early years to very recent dates on various topics such as material, tribology, equipment, tooling, etc., so that other researcher at different parts of the world can use it for further investigations in this area.
245 citations
TL;DR: The design and manufacturing of dies and molds represent a significant link in the entire production chain because nearly all mass produced discrete parts are formed using production processes that employ dies and mold as mentioned in this paper.
220 citations
TL;DR: In this paper, two-dimensional orthogonal slot milling experiments in conjunction with an analytical-based computer code are used to determine flow stress data as a function of the high strains, strain rates and temperatures encountered in metal cutting.
Abstract: In the present study, two-dimensional orthogonal slot milling experiments in conjunction with an analytical-based computer code are used to determine flow stress data as a function of the high strains, strain rates and temperatures encountered in metal cutting. The workpiece materials selected for the present study are AISI P20 mold steel (DIN 1.2330, 35CrMo4) hardened to 30 HRC, AISI H13 tool steel (DIN 1.2344, X40CrMoV51) hardened to 46 HRC and Aluminum EN AW 2007 (DIN 1725 T1: AlCuMgPb, 3.1645) cold hardened to 100 HB. The methodology of flow stress determination for metal cutting, suggested in the present study, has advantages when compared with methods such as the Hopkinson's bar technique. This paper summarizes the first part of the study, conducted to estimate process variables in machining operations. The second part of the study, summarized in a different paper, addresses the application of flow stress data for predicting forces, stresses and temperatures in machining.
164 citations
TL;DR: In this article, the characterization and specification of tubular material properties under hydroforming conditions is the main concern of this paper, and analytical improvements and their comparison with experimental findings on measurement of material properties of tubes under hydraulic bulging conditions are explained.
Abstract: Increasing acceptance and use of hydroforming technology within the automotive industry demands a comprehensive understanding of related issues such as material characteristics, tribology, part and tooling design. Among these issues, characterization and specification of tubular material properties under hydroforming conditions is the main concern of this paper. Analytical improvements and their comparison with experimental findings on measurement of material properties of tubes under hydraulic bulging conditions are explained. With these improvements, ‘on-line’ and continuous measurement of flow stress for tubular materials become possible, and are proven to be in good agreement with previous ‘off-line’ measurements presented by the authors.
110 citations
TL;DR: In this paper, a computer aided design method for straight flanging using finite element method is presented, and the predictions have been validated with some laboratory experiments, and this method was applied on a specific type of flanging in which the edge is coined at the end of the operation.
90 citations
TL;DR: In this paper, the influence of process variables, such as die shoulder radius, punch-die clearance, punch nose radius, pad force and material properties, on straight flanging was discussed.
79 citations
TL;DR: In this paper, the flow stress data of AISI H13 tool steel (46 HRC) was used to investigate the influence of edge preparation on forces in the cutting and feed directions, tool stresses and cutting temperatures.
Abstract: The flow stress data, determined in Part I of the present study, is validated by using it as an input to the finite element method and analytical based computer programs to predict process variables in metal cutting. The predicted process variables in two-dimensional orthogonal turning and three-dimensional face milling operations, are compared with the published experimental data and the results of experiments conducted in the present work. The majority of the predictions have been found to be in reasonable agreement with the measured results. The comparisons have been discussed and, in the case of unsatisfactory agreement, the reasons for inaccurate predictions are reviewed. The flow stress data of AISI H13 tool steel (46 HRC), determined in Part I is used in this study to investigate the influence of edge preparation on forces in the cutting and feed directions, tool stresses and cutting temperatures. It has been concluded that the hone-radius edge with a hone radius of 0.1 mm provides the maximum resistance to chipping and the chamfered edge (20°×0.1 mm) has the minimum flank and crater wears for the conditions used in the present study.
59 citations
TL;DR: In this article, the adaptive simulation technique is presented as an effective FEM approach, able to select a feasible THF loading path within a minimum number of simulation runs or even within a single run.
36 citations
2 citations