RU2220018C2 - Method of drawing and drawing die - Google Patents

Abstract

FIELD: plastic metal working; particularly, sheet-metal forming; possibly, manufacture of various parts out of sheet materials by means of method of drawing, predominantly automobile body parts, as well as parts of household appliances and agricultural equipment. SUBSTANCE: method of drawing incorporates steps of formation of outline of initial workpiece out of rectangular sheet, holding its peripheral zones and its further forming with deceleration of peripheral portion. Formation of initial workpiece outline out of rectangular sheet is carried out by means of incomplete cut of its peripheral zones in places of excess deceleration. As drawing is being started, additional deceleration is provided owing to bending or flanging of cut zones. Adjustment of additional deceleration is carried out by means of modifying cutting angles of punches while adjusting die or changing depth of their introduction into workpiece. Drawing die incorporates punch, die for drawing with holding surfaces, work- holding attachment, knives installed on work-holding attachment, and dies corresponding to each knife located on holding surfaces of drawing die. Knives are made in the form of cutting wedge punches with tapered lower portion and flanged upper portion. Dies corresponding to each knife are made in the form of flanged dies with radii on working edges being in accordance with thickness of formed metal over upper portion of wedge punches. EFFECT: optimization of operating process technologies for forming articles of complicated shape and reduced consumption of attachments for forming. 3 cl, 5 dwg

Description

 The invention relates to the field of metal forming, namely to sheet stamping, and can be used for the manufacture of various parts from sheet materials by drawing, mainly automotive body parts, as well as parts of household and agricultural machinery.

 A known method of drawing, including the formation of the contour of the initial billet from a rectangular sheet by cutting on a special stamp, clamping its peripheral zones and the final shaping of the panel with braking of the peripheral part, (see A.P. Nefedov. Design and manufacture of dies, M .: Engineering, 1973, p. 39, 40).

The method has the following disadvantages:
- high costs for the preparation of production associated with the need to manufacture a special die cutting stamp;
- high costs for the preparation of production in case of changes in the design of the stamped part, associated with the need for alteration, and sometimes the manufacture of a new stamp;
- the high cost and complexity of manufacturing a stamped panel associated with the need to perform additional cutting operations;
- the need for additional equipment for cutting down (press or a special automatic line for the manufacture of shaped blanks).

The closest technical solution is the drawing method (see A.P. Nefedov. Design and manufacture of dies, M .: Mechanical Engineering, 1973, p. 68, Fig. 49),
including forming the contour of the initial billet from a rectangular sheet, by trimming the corners directly with the working parts of the stamp, clamping its peripheral zones, further shaping it with braking the peripheral part and stamp for its implementation;
comprising a punch, an exhaust die with clamping surfaces, a clamp, knives mounted on the clamp, and corresponding matrices located on the clamping surfaces of the exhaust die.

This method of drawing and a device for its implementation have the following disadvantages:
- the high cost and complexity of manufacturing parts associated with the need for continuous removal of waste (trimmed corners of the workpieces) from the stamp on the operation of drawing;
- increased requirements for manufacturing accuracy, quality of adjustment and maintenance of exhaust dies in connection with the need to ensure the optimum cutting gap during cutting of the workpiece angles (for steels 8-12% of the material thickness);
- high costs for the preparation of production in case of changes in the design of the stamped part, the size of the initial billet or the need for additional introduction into the manufacturing process of the operation of trimming the corners of the initial rectangular billet, which is associated with significant alterations, and sometimes the manufacture of a newly expensive exhaust stamp.

The invention is aimed at:
- reducing the cost of preparation of production and optimization of existing technologies for stamping parts of complex shape, associated with a reduction in the required number of die tooling and expanding opportunities for high-quality adjustment of the drawing process by adjusting the amount of braking of metal in the areas of greatest deformation of the part during drawing;
- saving metal and reducing the cost of manufacturing stamped parts of complex shape by optimizing the size of the original billet and changing the braking pattern of the stamped metal during drawing;
- reducing the complexity and increasing labor productivity by eliminating the additional operation of cutting the curly blanks, as well as waste disposal in the most labor-intensive exhaust operation;
- simplifying the design and reducing the cost of manufacturing die tooling;
- simplification of maintenance and repair of dies.

The problem is achieved in that in the known method of drawing, including the formation of the contour of the initial workpiece from a rectangular sheet, clamping its peripheral zones and its further shaping with inhibition of the peripheral part;
the initial blank is formed from a rectangular sheet by notching its peripheral zones in places of excessive braking, which are subject to intense corrugation and rupture during drawing, and also provide additional braking at the initial drawing moment due to bending or flanging of the notched zones, the adjustment of which is carried out by changing the notch sharpening angles punches when adjusting the stamp or by changing the depth of their introduction into the workpiece.

With increasing depth of introduction of incised wedge-shaped punches into the workpiece, the angle of bending of the edge of the incised hole increases up to 90 ^o , corresponding to the flanging.

 With an increase in the angle of bending of the edge of the notched hole, additional braking at the initial moment of drawing increases. Changing the amount of additional braking, achieving the required value, also allows changing the sharpening angles of notched wedge-shaped punches, since this changes the height of the flanges of the flanged holes.

 In the known stamp for implementing the method comprising a punch, an exhaust die with clamping surfaces, a clamp, knives mounted on a clamp and corresponding matrices located on the clamping surfaces of the exhaust die, the result is that the knives are made in the form of incised wedge-shaped punches with a pointed lower part and flanging - the top, and matrices corresponding to the knives are made in the form of flanging, with radii on the working edges, taking into account the thickness of the stamped metal along the upper part of the wedge-shaped PUA nsonov.

 The sharpening angles of the wedge-shaped punches and the depth of their introduction into the workpiece are determined by adjustment.

The essence of the method of drawing and stamp for its implementation is illustrated by sketches:
- figure 1 shows a plan view of the matrix (working area of the stamp) with clamping surfaces on which flanging matrices are installed with a sheet blank installed on it;
- figure 2 is a stage of the formation of the original billet by notching the peripheral part of the sheet billet with bending the edges of the notched hole;
- figure 3 is a step of clamping the initial workpiece between the clamping surfaces of the matrix and the clamp, with folding or flanging the edges of the notched holes, depending on the depth of penetration of the notched punch into the workpiece;
- in FIG. 4 - the stage of the final shaping of the panel from a notched sheet blank;
- figure 5 - the influence of the sharpening angles of the punch on the height of the flange of the resulting flanged holes in the notch zone, where a is the symmetrical angle of sharpening of the punch; b - asymmetric sharpening angle of the punch.

 A smaller sharpening angle A1 corresponds to a lower flange height of the flanged hole - S1, a larger angle to sharpening A2 corresponds to a larger height - S2. When changing the height of the flanged flange from the side of the matrix aperture, the value of the additional braking of the metal during drawing varies accordingly.

 The stamp contains a punch 1, a matrix 2 with clamping surfaces 3 and flanging matrices 4 placed on it, a clamp 5 with notched knives mounted on it in the holders 6, made in the form of wedge-shaped punches 7, the surfaces of which are made with sharpening angles determined by adjustment.

 The drawing method is implemented in the stamp, which works as follows. Before stamping, the sheet blank is mounted on the clamping surface 3 of the matrix 2, so that its edges overlap the opening of the matrix 2.

 Then, in the process of clamping a sheet blank, in areas of excessive braking, which are subject to intense corrugation and ruptures during drawing, cuts are made in a rectangular sheet blank while bending or flanging the edges of the notched sheet, creating additional braking.

 The incisions are made by introducing wedge-shaped punches 7 installed on the clamp 5 in the holders 6 and the corresponding flanging matrices 4 into the sheet blank.

 As a result of clamping the sheet blank with the pressing surfaces 3 of the matrix 2 and the clamp 5, the wedge-shaped punches 7, having penetrated into the sheet blank, deform the edge of the notched holes, forming bent or flanged flanges, which are additional brake elements at the initial stage of the drawing process.

 During the course of the internal press slider, the part 1 is pulled down from the pre-cut and molded shell during clamping by the punch 1.

 The peripheral zone of the workpiece in this case has the ability to move from the clamping surfaces 3 of the matrix 2 and the clamp 5 into the opening of the matrix with the necessary braking, which is determined during the adjustment of the stamp. The metal of the workpiece, cut off by the wedge-shaped punches 7, is not involved in the shaping of the part. At the same time, the wall of the flanged hole, located closer to the exhaust opening, creating additional braking at the beginning of the hood, has the ability to move towards the opening of the matrix. The magnitude of this inhibition is adjusted in adjustment by changing the sharpening angles of the wedge-shaped punches 7 or by the depth of penetration into the workpiece.

 Such a braking pattern for the workpiece is created that allows stamping the most complex body parts from a rectangular sheet instead of a shaped blank, and the required overall dimensions of a rectangular sheet are smaller than the required overall dimensions of the sheet to produce a shaped blank.

 After completing the stroke of the punch 1, a semi-finished product is formed from the workpiece in the form of a panel or an exhaust transition, which is converted into a finished product during further stamping operations. The notched part of the rectangular billet, which is not involved in the creation of braking during the exhaust, is not separated from the exhaust transition and is disposed of for trimming operations. Further, the internal and external press sliders return to their original position, the exhaust transition is removed and the cycle repeats again.

 According to a similar scheme, a stamp is used to extract parts of complex shape on a simple press.

 Using the proposed method in the manufacture of parts 3110-8404020 / 21 "Rear right and left wing" eliminated the operation of cutting curly blanks, reducing the complexity and reducing metal consumption by 1.33 kg per car.

Claims (2)

1. The method of drawing, including the formation of the contour of the initial billet from a rectangular sheet, clamping its peripheral zones and its further shaping with braking of the peripheral part, characterized in that the formation of the contour of the initial billet from a rectangular sheet is performed by notching its peripheral zones in places of excessive braking, subjected to intense corrugation and rupture during the hood, provide additional braking at the initial moment of the hood due to bending or flanging of the incised zones, the adjustment of the value of which is carried out by changing the angles of sharpening of the notched punches during adjustment of the stamp or by changing the depth of their introduction into the workpiece. 2. A stamp for drawing, containing a punch, an exhaust die with clamping surfaces, a clamp, knives mounted on a clamp, and corresponding matrices located on the clamping surfaces of the exhaust matrix, characterized in that the knives are made in the form of incised wedge-shaped punches with a pointed lower part and the flanging top, and the matrices corresponding to the knives are made in the form of flanging with radii on the working edges, taking into account the thickness of the stamped metal along the upper part of the wedge-shaped punches.

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