Stretch forming die with composite structure and manufacturing method of stretch forming die

Abstract

The invention relates to the field of airplane metal envelope manufacturing, in particular to a stretch forming die with a composite structure and a manufacturing method of the stretch forming die. The stretch forming die comprises an upper die assembly and a lower die assembly, the upper die assembly is connected with the lower die assembly through a guiding positioning device assembly, the upper die assembly is located above the lower die assembly, a hole making device assembly of an envelope part positioning hole is arranged on the upper surface of the lower die assembly, and at least two earring-shaped hooks are arranged on the side face of the lower die assembly. The stretch forming die is provided with a lower die and an upper die , and the upper die and the lower die have the composite structural characteristic, a base body of the stretch forming die adopts a cast aluminum material and is provided with lightening grooves and reinforced ribs so that the total weight of the stretch forming die can be lightened obviously. Dovetail grooves which are distributed in a latticed mode on the molded surface of the cast aluminum base body can firmly hold machinable resin, and effectively prevent a machinable resin layer from cracking and falling down, and the service life of the stretch forming die is prolonged.

Description

technical field [0001] The invention relates to the field of aircraft metal skin manufacturing, in particular to a drawing die of a composite structure and a manufacturing method thereof. Background technique [0002] Due to the needs of the aircraft's aerodynamic shape and functional layout, some skins have a single-curved shape, some have a hyperboloid shape, and some have complex shapes with "S" and partial bulges or depressions. The surface accuracy of skin parts affects the quality of aircraft assembly, and the surface quality defects of metal skin parts such as crushing, scratches, wrinkles, orange peel, etc. affect the fatigue life of aircraft. Therefore, how to produce complex curved skin with high quality and high efficiency is a It is one of the important topics that the aircraft manufacturing main engine factory has been researching and improving. [0003] The drawing die is an important special process equipment for forming aircraft metal skin. Its structure, pr...

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Problems solved by technology

[0010] The mold forming principle and structure of the above-mentioned patents are significantly different: the attached patent belongs to the multi-point forming technology, which discretizes the overall mold and controls the Z-direction coordinates of several scattered and regularly arranged small basic unit bodies (ball cylinders) by computer (height value), forming several three-dimensional "point clouds" in space, so as to form the curved surface shape of the product parts in an "approximate and fitting" way; the mold functions are significantly different: the mold of the multi-point forming technology is a "universal "equipment", which can only be used for part surface forming, and cannot be used for precise inspection of the geometric accuracy of different parts, shape inspection, and other tooling such as cutting templates and chemical milling templates. The surface quality of the formed product parts is different: many Due to the characteristics of the forming principle of the product parts formed by point forming technology, there are some defects such as point-like indentations, linear slip marks, concave-convex ripples and other defects on the upper and lower sides of the product parts, especially in the annealed state below the forming 3mm (softer, but the fluidity is good) when the sheet metal material has obvious defects

Although the anti-wrinkle multi-point forming technology and elastic pad isolation technology have been adopted, the surface defects of product parts have been reduced, but they still cannot meet the surface quality requirements of modern aircraft skin parts.

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