SU1303221A2 - Method of drawing hollow articles from sheet blank - Google Patents

Abstract

The invention relates to the field of metal forming and can be used in mechanical engineering when drawing hollow articles from sheet blanks. The purpose of the invention is to improve the quality by preventing the formation of marks from the corrugations on the wall of the finished product. The workpiece is mounted on the “mirror of the matrix and affects its peripheral part of the working surface of the clamp. As a result, a cone is drawn in the direction of the extrusion on the peripheral part by an angle, the value of which is calculated from a certain relationship. Then, the central part of the preform is subjected to a drawing force until stable corrugations form on its peripheral part. After that, the preform is pulled into the matrix, straightening the obtained corrugations. As a result, the range of use of the exhaust method is expanded by the precise manufacture of thin-walled parts with a dome-shaped bottom part. 2 Il. SO about so you Yu

Description

The invention relates to the processing of metals by pressure and relates to methods for drawing hollow articles from sheet stocking.

The purpose of the invention is to improve the quality by preventing the formation of marks from the corrugations on the wall of the finished product.

FIG. 1 shows a device for implementing the method, to the left of the axis of symmetry — in the initial state, to the right, at the time of forming the cone; in fig. 2 - the same, to the left of the axis of symmetry - at the initial moment of stretching, to the right - to the final one.

A device for implementing the method comprises a coaxially mounted punch 1 and a die 2 with a conical “mirror, as well as a presser 3 installed with a conical working surface coaxially mounted to the punch 1. Position 4 marked workpiece.

The method is carried out as follows.

Flat sheet workpiece 4 is exchanged. 1. a between the matrix 2 and the clamp 3 - (Fig. 1). The clamp 3 is fed and pressed against the matrix 2 (Fig. 2). At the same time on the peripheral part of the workpiece is molded a cone at an angle ak, calculated by the following formula:

39.8677-t-ri- (2-n), ak f

between the mirror of the matrix 2 3. defined by the expression:

n clamp

where n is the exponent of the equation for the power approximation of the hardening curve of the material;

t is the thickness of the workpiece;

r is the radius of the extended product;

RO is the work radius.

The peripheral portion of the preform 4, after forming the cone, is located in a narrowing cavity between the mirror of the matrix 2 and the clamp 3.

The central part of the workpiece 4 is affected by the deformation force from the side of the punch 1 to the formation on its peripheral part of conical radial corrugations with increasing height to the periphery, while the height of the corrugations is limited (Fig. 3). The radial profile of the formed corrugations corresponds to the angle a

1,7552-n-t

where n

t

g

R,)

(one---)

exponent of the equation for the power approximation of the material hardening curve; workpiece thickness; radius of exhaustable 0 0 products; the radius of the workpiece.

After the formation of stable corrugations during the further course of the punch 1 posit, there is a 5

0

five

0

five

0

five

is stretching the blank 4 with straightening these corrugations in a narrowing cavity. At the end of the stretching process, the corrugations located at the outer edge of the flange are straightened in the narrowest part of the tapering cavity (Fig. 4). Then, the punch, clamp 3 is retracted and the product is removed (not shown)

The angle ak of bending the peripheral part of the workpiece when forming a cone depends on the thickness t of the material of the workpiece 4, the radius Ro of the workpiece 4, the radius g of the finished product and the hardening rate of p. The angle ak is found due to the absence of a cone forming eliminates distortion of the peripheral part of the workpiece in a narrowing cavity prior to the impact of the deformation force on the central part of the workpiece. This ensures that the radial conical corrugations are evenly distributed along the peripheral part when the central part of the workpiece is subjected to a deforming force. The direction of the bending of the peripheral part during the molding of the cone was found from the condition of complete straightening of the corrugations and preventing the transition of the corrugations to the product.

The use of the proposed method of stretching provides, in comparison with the known, an improvement in the quality of products and a reduction in scrap by 85-95% as a result of the absence of traces of corrugations on the walls of products. In addition, the range of use of the drawing method is expanded due to the high geo-metric accuracy achieved for the manufacture of thin-walled parts with a dome-shaped bottom part.

Claims (1)

Invention Formula Method of drawing hollow articles from sheet stock according to ed. St. No. 1245383, characterized in that, in order to improve quality by preventing the formation of marks from the corrugations on the wall of the finished product, before the central part of the workpiece is subjected to a deforming force on the peripheral part of the workpiece, a cone is formed in the drawing direction at an angle ak determined from the following; his expressions: 39.8677- / - (2-) ak :: ;;: g. f - "V G 7 where t is the thickness of the workpiece; n is the exponent of the equation of the foam approximation of the curve of the material being mated; r is the radius of the product being pulled; / () - the radius of the workpiece. FIG. Fa G. 2 Editor K. Voloshchuk Order 1244/9 VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4 Compiled by O. Matveeva Tehred I. VeresKorrektor E. Roshko Circulation 733 Subscription