Determination method for plate incremental forming limit diagram

Abstract

The invention discloses a determination method for a plate incremental forming limit diagram. The plate incremental forming limit diagram is finally obtained by drawing curves, generating a processing program, preparing samples, forming arc grooves, obtaining a plate plane limit strain value and establishing a plate plane strain coordinate system. A hemispherical head forming tool is adopted to form a unidirectional arc groove and equal-width cross arc grooves, an ellipsoidal head forming tool different in long axis and short axis proportions is adopted to respectively form unequal-width cross arc grooves, and the plate plane limit strain value is obtained by analysis. The method is reasonable, simple and rapid, the plate incremental forming limit diagram high in accuracy can be obtained, guarantee is provided for making a reasonable production process, and criteria are provided for numerical simulation.

Description

technical field [0001] The invention belongs to the technical field of sheet metal forming and processing, and in particular relates to a method for establishing a progressive limit graph of sheet metal. Background technique [0002] Compared with traditional sheet metal stamping forming, NC incremental forming does not require molds or only punches, and can quickly complete the forming of parts with the help of workpiece CAD models, which is especially suitable for new product development and the production of single-piece or small-batch sheet metal parts. , Incremental forming also has the advantages of low cost, small forming force, and high formability of sheet metal, and can be widely used in industries such as aviation, aerospace, home appliances, medical equipment, and automobile manufacturing. [0003] The forming limit diagram is the main basis for judging whether the sheet will fail. In the traditional sheet metal forming limit diagram, the forming limit curve is ...

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Problems solved by technology

When the straight groove method is used to measure the incremental forming limit diagram of the sheet metal, the rupture position is always located at both ends of the groove, and the obtained strain state at the rupture position is close to the biaxial tensile strain state. It is necessary to assume that the slope of the incremental forming limit curve is -1, and the measurement results are accurate When the helical path processing truncated cone method is used to determine the forming limit diagram of sheet metal, reasonable control parameters are required to control the continuous cracking of the sheet metal during the processing process, and the deformation required for the cracking of sheets of different thicknesses and materials Different, in order to obtain suitable parameters, multiple experiments are required, and the method is cumbersome and complicated

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