Influence of process parameters on mechanical properties of lamination stacks produced by interlocking

Influence of process parameters on mechanical properties of lamination stacks produced by interlocking

MARTIN Daniel Michael, KUBIK Christian, KRÜGER Martin, GROCHE Peter

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Abstract. Interlocking is mainly used in the manufacture of lamination stacks for the cores for electrical energy converters. The process involves the embossing of nubs, which are subsequently stacked and joined by an interference fit. For an optimal design of interlocked joints, sufficient knowledge of the relationships between various influencing parameters in the manufacture and the resulting stack properties is essential. In addition to the design parameters nub geometry, size and embossing depth, the process parameters embossing clearance, counterpunch and blankholder force influence the joint strength. In addition to these fixed parameters, continuously varying uncertainty such as wear, which can lead to a rounding of the tool edges, affects relevant stack properties like the joint strength. The mechanical loads in the area of the tool edge which are responsible for this rounding mainly act immediately before material separation and have to be considered in the embossing process. However, the influence of punch edge radii on the joint properties during the interlocking process has not yet been investigated. In order to describe the interdependencies between different influencing parameters on the achievable mechanical strength, experimental investigations are carried out. Therefore, cylindrical nubs are interlocked with varying embossing depth, clearance and edge radii. The joint strength is determined via tensile tests. Key findings are that the joint strength of nubs with increasing abrasive wear on the cutting edge of the embossing tool are compensated by a higher embossing depth. The minimum embossing depth required for stacking and the embossing depth at which the optimum strength is achieved depend on the embossing edge radius and thus on the current abrasive wear state.

Interlocking, Lamination Stacks, Electrical Steel

Published online 4/19/2023, 10 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: MARTIN Daniel Michael, KUBIK Christian, KRÜGER Martin, GROCHE Peter, Influence of process parameters on mechanical properties of lamination stacks produced by interlocking, Materials Research Proceedings, Vol. 28, pp 1101-1110, 2023


The article was published as article 121 of the book Material Forming

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