Hot forming method for variable-curvature skin sheet metal part

Abstract

The invention discloses a hot forming method for a variable-curvature skin sheet metal part, and belongs to the technical field of sheet metal and thermoforming. The problems that wrinkles, cracks and the like are prone to occurring in hot forming of existing variable-curvature skin sheet metal parts, and the forming period is long are solved. According to the method, the unfolding size of the part is calculated through a finite element analysis method, and the problem of local wrinkles after part forming is effectively solved by optimizing the mold structure and changing the part hot-pressing mode. The changed contour of an unfolded material effectively gets rid of the complex stress influence of excessive process allowance on the position where the hot formed wrinkles are prone to occurring, and profile-followed attachment of a plate in the thermoforming process is facilitated; plate positioning holes are designed in the two ends of the unfolded material and serve as fixing holes of the hot formed plate, and the plate positioning holes also server as positioning holes for subsequent laser cutting of the part, so that the working efficiency of laser cutting of the part is greatly improved.

Description

technical field [0001] The invention relates to a method for hot-press forming a skin-like sheet metal part with variable curvature, and belongs to the technical field of sheet metal and thermoforming. Background technique [0002] The skin is a large-size sheet metal part with variable curvature. Its structure is a "saddle"-shaped sheet metal part with a concave middle part and upturned ends. Due to its large size and large curvature change, superplastic forming method is adopted. Improper air pressure control can easily lead to uneven wall thickness of parts and it is difficult to meet the shape requirements of skin parts. In the prior art, the thermoforming process is often used for forming, which has the characteristics of simple and convenient manufacturing process and low cost. However, because the sheet metal material has certain plasticity at high temperature, the thermoforming method is directly used in the hot pressing process due to the large curvature of the shap...

AI Technical Summary

Problems solved by technology

[0002] The skin is a large-size sheet metal part with variable curvature. Its structure is a "saddle"-shaped sheet metal part with a concave middle part and upturned ends. Due to its large size and large curvature change, superplastic forming method is adopted. Improper air pressure control can easily lead to uneven wall thickness of parts, which is difficult to meet the shape requirements of skin parts

In the prior art, the thermoforming process is often used for forming, which has the characteristics of simple and convenient manufacturing process and low cost. However, because the sheet metal material has certain plasticity at high temperature, the thermoforming method is directly used in the hot pressing process due to the large curvature of the shape. Medium-sized materials cannot be discharged in a limited space, and large-area wrinkles, cracks and other defects will inevitably occur, resulting in a pass rate of only 15%.

Moreover, the existing skin thermoforming often requires thermal correction after thermoforming, and the process cycle is long

Images