Tensile stresses in fine blanking tools and their relevance to tool fracture behavior

Krobath, Martin; Klünsner, Thomas; Ecker, Werner; Deller, M.; Leitner, N.; Marsoner, S.

doi:10.1016/j.ijmachtools.2017.12.005

Cited by 20 publications

(5 citation statements)

References 18 publications

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“…Deep rolling is a promising technology for increasing the service life of alternately loaded fine blanking punches [4]. Deep rolling is an industrially established process that is used to increase the service life of dynamically loaded components [5].…”

Section: Introductionmentioning

confidence: 99%

Modification of the surface integrity of powder metallurgically produced S390 via deep rolling

Herrmann

2023

Materials Research Proceedings

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Abstract. Fine blanking is an economical process for manufacturing sheet metal workpieces with high sheared surface quality. When machining high-strength steels, material fatigue leads to increased punch wear, which reduces the economic efficiency of the process. This fatigue of the cutting edge and lateral punch surface can be counteracted by mechanical surface treatments. Deep rolling has proved particularly useful for such surface modification, as it allows both: machining of the lateral punch surface and the application of the cutting edge rounding required for fine blanking. For the precise design of the fine blanking punch contour especially the macroscopic deformation of the workpiece is decisive. In this paper, the possibility of specifically modifying the surface integrity of hardened and powder metallurgically produced S390 by means of the incremental surface treatment process deep rolling is investigated. By varying the decisive process parameters rolling pressure, ball diameter and step over distance, their influence on surface integrity is determined. The surface integrity is afterwards characterized by macro hardness, surface topography and residual stress state and microstructural images.

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Section: Introductionmentioning

confidence: 99%

Modification of the surface integrity of powder metallurgically produced S390 via deep rolling

Herrmann

2023

Materials Research Proceedings

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“…To simulate the processes of separating rolled stock into dimensional workpieces various CAE systems are used; they are based on the finite element method: ANSYS [17], LS-DYNA [18], DEFORM 3D [19], QFORM [20]. The obtained results of finite element analysis allow the researcher to understand the main trends of the separation process and to obtain fairly accurate quantitative data concerning the distribution of temperature-velocity fields and tensor`s components of stress-strain state [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Development and research of the stamp for cutting of a rolled stock with a differentiated clamp

Karnaukh¹,

Марков²,

Shapoval³

et al. 2022

FME Transactions

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The work aims to develop and research a stamp with a differentiated clamp of a rolled stock for cutting by shear. A new stamp design with a differentiated clamp of the rolled stock has been developed. In terms of their technical and economic indicators, these stamps meet or exceed the modern samples of similar punch tools. At the same time, in the process of vertical cutting, a constant position of the rolled stock axis is ensured. The transmission of force to the clamp through the rolled stock is excluded. The stamp design ensures its sufficiently high rigidity and relatively small overall dimensions. Based on the analysis of the mathematical model of a stamp with a differentiated clamp, the effective angles of force transmission to the clamp and the cutting of the rolled stock between the stamp parts have been established. The resulting model was used to optimize the angles of force transfer to the clamp, and the cutting rolled stock, respecting the force from the side of a buffer and the minimum required press force. At the same time, the vertical stroke of the moving parts is reduced, the overall dimensions of the stamp are decreased, and the buffer also has a minimum size. To reduce the required force of the press, it is necessary to reduce the value of a frictional slipping coefficient by using antifriction materials on contact surfaces and ensuring good lubrication conditions. The results of the conducted experiments confirm the adequacy of the mathematical model. The value of the required force on the press slide available from experiments is slightly higher than the values obtained by the developed analytical model. The results of the stamp implementation show that: the stamps are efficient and reliable in exploitation; the quality of the cutoff workpieces corresponds to the quality indicators of the workpieces cut on similar modern equipment.

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“…Krobath et al [3] investigated the load cycle of the punch in the fine-blanking process and the unload cycle of the punch withdrawing after punching. Their study focused on the tensile load and local stress ratio of the punch and analyzed the smallest defects on the surface of the WC-Co hardened steel punch under fatigue load conditions to quantitatively estimate and calculate the critical value of fatigue crack growth.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Optimization of Fine-Blanking Process for Copper Alloy Sheet

Kuo

Liu

et al. 2021

Preprint

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When the fine-blanking process is used, secondary grinding or processing can be omitted because the shear surface of fine-blanking parts can achieve almost zero fracture zone requirements. Fine-blanking has the advantages of high precision and high production efficiency. It was originally used on watch parts, but with increasingly refined technology, it has been widely applied in computers, consumer electronics, communication products, and vehicle parts. The primary objective of the fine-blanking process is to reduce the fracture zone depth and die roll zone width. This study used a 2.5mm thick central processing unit (CPU) thermal heat spreader as an example. Finite element analysis software was employed to simulate and optimize the main eight process parameters that affect the fracture zone depth and die roll zone width after fine-blanking: the V-ring shape angle, V-ring height of the blank holder, V-ring height of the cavity, V-ring position, blank holder force, counter punch force, die clearance, and blanking velocity. Simulation analysis was conducted using the L18 (21×37) Taguchi orthogonal array experimental combination. The simulation results of the fracture zone depth and die roll zone width were optimized and analyzed as quality objectives using Taguchi’s smaller-the-better design. The analysis results revealed that with fracture zone depth as the quality objective, 0.164 mm was the optimal value, and counter punch force made the largest contribution of 25.89%. In addition, with die roll zone width as the quality objective, the optimal value was 1.274 mm, and V-ring height of the cavity made the largest contribution of 29.45%. Subsequently, this study selected fracture zone depth and die roll zone width as multi-criteria quality objectives and used the robust multi-criteria optimal approach and Pareto-optimal solutions to perform multi-criteria optimization analysis. The results revealed the optimal fracture zone depth and die roll zone width were 0.239 mm and 1.288 mm, respectively. Finally, the experimental results verified that the fracture zone depth was 0.230 mm and die roll zone width was 1.205 mm. The findings met the industry’s fraction zone depth standard (below 12% of blank thickness) and achieved a smaller die roll zone width.

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Tensile stresses in fine blanking tools and their relevance to tool fracture behavior

Cited by 20 publications

References 18 publications

Modification of the surface integrity of powder metallurgically produced S390 via deep rolling

Modification of the surface integrity of powder metallurgically produced S390 via deep rolling

Development and research of the stamp for cutting of a rolled stock with a differentiated clamp

Numerical Simulation and Optimization of Fine-Blanking Process for Copper Alloy Sheet

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