CN102728706B - Method for continuously and unevenly compressing and forming three-dimensional curved surface - Google Patents

Abstract

The invention provides a method for continuously and unevenly compressing and forming a three-dimensional curved surface by using a sheet metal, belongs to the field of metal plastic processing and is especially suitable for the quick forming of a double-curvature three-dimensional curved surface part. The method is characterized in that the continuous forming of the curved surface is realized by paired upper and lower forming tools and the feeding motion of the sheet metal. When the sheet metal continuously passes by the forming tools, a plastic deforming area with a cross section having a curved shape and a thickness gradually reducing along the feeding direction of the sheet metal is formed at a gap of the upper and lower forming tools. The sheet metal is subjected to horizontal bending deformation and uneven compressing deformation along thickness direction in the deforming area; the uneven extension volume of the sheet metal along the horizontal direction is caused by the uneven compressing, so that an additional longitudinal bending moment is formed on the bent cross section and the sheet metal is longitudinally bent; and following the longitudinal continuous feeding of the sheet metal, a double-curvature three-dimensional curved surface is formed under the combined action of the horizontal and longitudinal bending deformation.

Description

The method of continuous and uneven compression molding three-dimension curved surface

Technical field

The present invention relates to a kind of sheet forming method, belong to Metal Forming field, be specially adapted to the Quick-forming of Double curve degree three-dimension curved surface part.

Background technology

Three-dimension curved surface part is widely used in the manufacture fields such as aircraft, steamer, bullet train, pressure vessels for the chemical industry, and in modern building fabric and sculpture for city, the demand of Double curve degree curved surface is also increasing.These curved surface parts are single-piece, small lot batch manufacture normally, and the shape of part is varied, and the quantity of every kind of Shape Parts is few.Traditional die forming technology is suitable for the production in enormous quantities of part, for the small lot of curved surface part, adds man-hour, and die cost is too high, thereby no longer applicable.Because traditional process technology can not meet actual requirement, the processing of single-piece, small lot curved-surface piece has become the technical bottleneck problem of numerous areas.

The method of chrominance signal progressive forming three-dimension curved surface is a kind of effective way that solves single-piece, small lot curve generating problem.The required plastic force of this manufacturing process is little, and device structure is simple, cost is low, can realize three-dimension curved surface part fast, efficient, low-cost processing.

Summary of the invention

The invention provides a kind of method that is gone out three-dimension curved surface by metal blank progressive forming.Metal blank obtains the chrominance signal distortion of transverse curvature distortion and thickness direction in deformed area, and chrominance signal causes the elongation of plate along horizontal uneven distribution, thereby on crooked cross section, causes additional vertical bending moment, makes plate buckling.Along with longitudinal continuous feed of plate, under the acting in conjunction of horizontal and buckling deformation, form the three-dimension curved surface of Double curve degree.

Above-mentioned purpose of the present invention is achieved through the following technical solutions, and accompanying drawings is as follows:

A kind of method of continuous and uneven compression molding three-dimension curved surface, make metal blank 3 continuous feeds, by the curve shape gap between upper and lower forming tool by chrominance signal after, at the port of export, form the curved surface 4 of Double curve degree, the center line in the gap of described forming tool is curve shape, and the width in gap is that non-equivalent distributes, and concrete steps are as follows:

1) determine the principal direction of curvature of the target curved surface of drip molding, when curve generating, make the direction of feed of metal blank 3 longitudinally consistent with a principal direction of curvature of drip molding target curved surface, forming tool edge is lateral arrangement perpendicular to plate direction of feed, consistent with another principal direction of curvature of the target curved surface of drip molding, and determine the target curved surface longitudinal curvature ρ of drip molding _land cross-section curve z=c (x), wherein z is short transverse coordinate.

2) determine the gap width function h (x) between upper and lower forming tool, this function should be the linear function of short transverse coordinate z, when vertical curvature and the lateral flexure rate of being shaped is convex surface 4a in the same way, in the middle of the width value of gap 2a is distributed as, little both sides are large, for symmetrical convex surface, the width computing formula of gap 2a is:

$h\left(x\right)=[1-(1-\frac{c\left(x\right)}{d})\frac{d}{{\mathrm{\ρ}}_L}]H$

Wherein H is the thickness of plate 3; ρ _llongitudinal curvature radius for drip molding target curved surface; D is the maximum height difference on target curved surface cross-section curve c (x).

During the reverse saddle type curved surface 4b of vertical curvature and the lateral flexure rate of being shaped, the width value of gap 2b is distributed as narrowing toward each end broad in the middle, and for symmetrical saddle type curved surface, the width computing formula of gap 2b is:

$h\left(x\right)=\left[1-\frac{c\left(x\right)}{{\mathrm{\ρ}}_L}\right]H$

3) described forming tool is strip, and has minor deflection bending, and its contour shape is adjusted by Tiao Xing mechanism 6, and the computing formula of upper forming tool contour shape curve is: f ₁(x)=c (x)+h (x)/2; The computing formula of lower forming tool contour shape curve is: f ₂(x)=c (x)-h (x)/2.

4) the be shaped computing formula of its longitudinal curvature radius of curved surface (4) of is:

Wherein A is the area in gap between upper and lower forming tool.

Described metal blank 3 feeding modes adopt external force drive into or by upper and lower shaping jig drive into.

Described forming tool adopts upper forming tool 1a and lower forming tool 1b, in forming process, maintains static, and by applying external force, makes plate feeding.

Described forming tool adopts upper flexible roller 7a and lower flexible roller 7b, and in forming process, upper and lower flexible roller is around self axis rotation, and drives plate feeding.

The present invention for solving single-piece, small lot Machining of Curved Surface problem provides a kind of effective way.This method is set up based on inhomogeneous attenuate and transverse curvature distortion, only needs upper and lower two forming tools, and its device structure is simple, cost is low.Because larger plastic deformation occurs plate material in compression thinning process, therefore, the resilience of this curved surface forming method is little, can obtain good forming effect.

Accompanying drawing explanation

Fig. 1 is curved surface progressive forming method schematic diagram.

The transverse cross-sectional view in upper and lower forming tool gap when Fig. 2 a (1) is shaping convex surface.

The longitudinal sectional drawing in upper and lower forming tool gap when Fig. 2 a (2) is shaping convex surface.

The transverse cross-sectional view in upper and lower forming tool gap during Fig. 2 b (1) shaping saddle type curved surface.

The longitudinal sectional drawing in upper and lower forming tool gap during Fig. 2 b (2) shaping saddle type curved surface.

Fig. 3 is for the sheet metal deformation schematic diagram of curved surface progressive forming process is described.

Fig. 4 is the tune shape structural representation of adjusting shaping tool wheel profile shape and gap.

Fig. 5 a is that forming tool is the curved surface progressive forming mode schematic diagram of flexible roller.

Fig. 5 b is the fixed curved surface progressive forming of forming tool mode schematic diagram.

In figure: the upper forming tool of 1a., forming tool under 1b., upper and lower forming tool gap during 2a. shaping convex surface, upper and lower forming tool gap during 2b. shaping saddle type curved surface, 3. plate, 4. profile surface, 4a. convex-shaped surface profile surface, 4b. saddle type profile surface, 5. sheet metal deformation district, 6. forming tool is adjusted shape structure, the upper forming rolls of 7a., forming rolls under 7b..

The specific embodiment

Below in conjunction with accompanying drawing illustrated embodiment, further illustrate particular content of the present invention and the course of work thereof.

The progressive forming of curved surface mainly realizes by the upper forming tool 1a of pairing and the feed motion of lower forming tool 1b and plate.Upper forming tool 1a and lower forming tool 1b are strip, and can minor deflection bending, along arranging perpendicular to plate direction of feed (laterally).Adjust after shape gap 2a, the 2b of forming curves shape between upper forming tool 1a and lower forming tool 1b.When plate process forming tool, place, gap between upper and lower forming tool, formation makes plate through-thickness produce the die cavity of compression, and the width of die cavity is along forming tool length direction (laterally) non-uniform Distribution, along the descending variation of direction of feed (longitudinally) of plate.

Described forming tool can consist of upper flexible roller 7a and lower flexible roller 7b.In forming process, flexible roller, around self axis rotation, drives plate 3 edges perpendicular to forming tool direction (longitudinally) feeding.

Described upper forming tool 1a and lower forming tool 1b maintain static, and by applying external force, make plate 3 edges perpendicular to forming tool direction (longitudinally) feeding.

Forming tool adopts above-mentioned two kinds of modes just to change the feeding mode of sheet metal, and the parameter of sheet metal forming process is identical.

By adopting described constituted mode, along with plate 3 is along the continuous feed perpendicular to forming tool direction, between upper and lower forming tool, form stable plastically deforming area 5.The chrominance signal distortion of plate 35 interior acquisition transverse curvature distortion and thickness direction in deformed area, chrominance signal causes plate along horizontal inhomogeneous elongation, cause on crooked cross section, forming additional vertical bending moment, thus make distortion after plate at port of export buckling deformation.Plastically deforming area 5 be one perpendicular to the local bar-shaped zone of direction of feed (laterally), feed motion along with plate 3, deformed region 5 longitudinally continuously changes position on plate, finally distortion is expanded to whole plate, the curved surface part 4 of the Double curve degree that is shaped.

The contour shape of described forming tool 1a, 1b is adjusted by Tiao Xing mechanism 6, and

The contour shape curve of upper forming tool (1a) is:

f ₁(x)＝c(x)+h(x)/2

The contour shape curve of lower forming tool (1b) is:

f ₂(x)＝c(x)-h(x)/2

The cross-section curve of the target curved surface that wherein z=c (x) is drip molding, z is short transverse coordinate, and c (0)=0; H (x) is the width in upper and lower forming tool gap.

The gap of described upper and lower forming tool is when curve generating, and its shape and width are adjusted according to the target curve form of drip molding, and

The center line in upper and lower forming tool gap is consistent with target curved surface cross-section curve, is: c (x);

If the width in gap is that middle little both sides are large, the vertical curvature of profile surface and lateral flexure rate in the same way, are convex surface 4a.While being shaped convex surface symmetrical, the width computing formula of gap 2a is:

$h\left(x\right)=[1-(1-\frac{c\left(x\right)}{d})\frac{d}{{\mathrm{\ρ}}_L}]H$

Wherein H is the thickness of plate 3; ρ _llongitudinal curvature radius for drip molding target curved surface; D is the maximum height difference on target curved surface cross-section curve c (x).

If the width in gap is narrowing toward each end broad in the middle, vertical curvature and the lateral flexure rate of profile surface are reverse, are saddle type curved surface 4b.While being shaped saddle type curved surface symmetrical, the width computing formula of gap 2b is:

$h\left(x\right)=\left[1-\frac{c\left(x\right)}{{\mathrm{\ρ}}_L}\right]H$

Described curved surface progressive forming method, the computing formula of its longitudinal curvature radius of curved surface (4) that of being shaped is:

Wherein A is the area in gap between upper and lower forming tool (1a, 1b).

Fig. 1 is curved surface progressive forming method schematic diagram.The curved surface progressive forming process the present invention relates to mainly realizes by the upper forming tool 1a of pairing and the feed motion of lower forming tool 1b and plate.The gap of forming curves shape, width value uneven distribution between upper and lower forming tool, consults shown in Fig. 2 a, Fig. 2 b.Described metal blank 3 continuous feeds, when when the upper and lower forming tool, form cross section and are curve shape, thickness along the plastically deforming area 5 of the descending variation of plate direction of feed at place, gap, consult shown in Fig. 3.Plate 3, along laterally because caused inhomogeneous elongation by chrominance signal, causes buckling deformation, forms continuously the curved surface 4 of Double curve degree at the port of export.

The length feed of described plate 3 can be realized by two kinds of modes.Fig. 5 a is that forming tool is the curved surface progressive forming mode of flexible roller, and forming tool wherein consists of upper flexible roller 7a and lower flexible roller 7b.In forming process, flexible roller, around self axis rotation, drives plate 3 length feeds.Fig. 5 b is the fixed curved surface progressive forming of forming tool mode, in forming process, by applying external force, makes plate 3 length feeds.

The step that the present invention realizes curved surface progressive forming is as follows:

1. determine the principal direction of curvature of the target curved surface of drip molding.When curve generating, the direction of feed (longitudinally) that makes plate is a principal direction of curvature, and the arranged direction of forming tool (laterally) is another principal direction of curvature.And calculate the longitudinal curvature ρ of target curved surface _land cross-section curve c (x).

2. determine the gap h (x) between upper and lower forming tool.If the curved surface being shaped is vertical curvature and lateral flexure rate convex surface 4a in the same way, the width in gap is that middle little both sides are large, as shown in Figure 2 a.For symmetrical convex surface, the width computing formula of gap 2a is:

$h\left(x\right)=[1-(1-\frac{c\left(x\right)}{d})\frac{d}{{\mathrm{\ρ}}_L}]H$

Wherein H is the thickness of plate 3; D is the maximum height difference on target curved surface cross-section curve c (x).

If the curved surface being shaped is for indulging the reverse saddle type curved surface 4b of curvature and lateral flexure rate, the width in gap is narrowing toward each end broad in the middle, as shown in Figure 2 b.For symmetrical saddle type curved surface, the width computing formula of gap 2b is:

$h\left(x\right)=\left[1-\frac{c\left(x\right)}{{\mathrm{\ρ}}_L}\right]H$

3. by the Tiao Xing mechanism 6 shown in Fig. 4, adjust the contour shape of forming tool.The contour shape curve of upper forming tool 1a is adjusted into: f ₁(x)=c (x)+h (x)/2; The contour shape curve of lower forming tool 1b is adjusted into: f ₂(x)=c (x)-h (x)/2.

4. by plate feeding, carry out the progressive forming of curved surface.

(1), for the forming mode shown in Fig. 5 a, the rotation by flexible roller around self axis, drives plate 3 length feeds, realizes the progressive forming of curved surface.

(2) for the forming mode shown in Fig. 5 b, by applying external force, make plate 3 length feeds, realize the progressive forming of curved surface.

Claims (4)

1. the method for a continuous and uneven compression molding three-dimension curved surface, make metal blank (3) continuous feed, by the curve shape gap between upper and lower forming tool by chrominance signal after, at the port of export, form the profile surface (4) of Double curve degree, the center line in the gap of described forming tool is curve shape, and the width in gap is that non-equivalent distributes, and concrete steps are as follows:

1) determine that profile surface (4) is the principal direction of curvature of the target curved surface of drip molding, when curve generating, make the direction of feed of metal blank (3) longitudinally consistent with a principal direction of curvature of drip molding target curved surface, forming tool edge is lateral arrangement perpendicular to plate direction of feed, consistent with another principal direction of curvature of the target curved surface of drip molding, and determine the target curved surface longitudinal curvature ρ of drip molding _land cross-section curve z=c (x), wherein z is short transverse coordinate.

2) determine the gap width function h (x) between upper and lower forming tool, this function should be the linear function of short transverse coordinate z, when vertical curvature and the lateral flexure rate of being shaped is convex-shaped surface profile surface (4a) in the same way, in the middle of the width value in gap (2a) is distributed as, little both sides are large, for symmetrical convex-shaped surface profile surface (4a), the width computing formula of gap (2a) is:

$h\left(x\right)=[1-(1-\frac{c\left(x\right)}{d})\frac{d}{{\mathrm{\ρ}}_L}]H$

Wherein H is the thickness of plate (3); ρ _llongitudinal curvature radius for drip molding target curved surface; D is the maximum height difference on target curved surface cross-section curve c (x).

During the reverse saddle type profile surface (4b) of vertical curvature and the lateral flexure rate of being shaped, the width value of gap (2b) is distributed as narrowing toward each end broad in the middle, and for symmetrical saddle type profile surface (4b), the width computing formula of gap (2b) is:

$h\left(x\right)=[1-\frac{c\left(x\right)}{{\mathrm{\ρ}}_L}]H$

3) described forming tool is strip, and has minor deflection bending, and its contour shape is adjusted by Tiao Xing mechanism (6), and the computing formula of upper forming tool contour shape curve is: f ₁(x)=c (x)+h (x)/2; The computing formula of lower forming tool contour shape curve is: f ₂(x)=c (x)-h (x)/2.

4) the be shaped computing formula of its longitudinal curvature radius of curved surface (4) of is:

${\mathrm{\ρ}}_L=\frac{{\left[{\∫}_{A}c\left(x\right)\mathrm{dA}\right]}^2-A{\∫}_A{c}^2\left(x\right)\mathrm{dA}}{\frac{1}{H}[{\∫}_{A}h\left(x\right)\mathrm{dAg}{\∫}_{A}c\left(x\right)\mathrm{dA}-A{\∫}_{A}h\left(x\right)c\left(x\right)\mathrm{dA}]}$

Wherein A is the area in gap between upper and lower forming tool.

2. the method for a kind of continuous and uneven compression molding three-dimension curved surface according to claim 1, is characterized in that, described metal blank (3) feeding mode adopt external force drive into or by upper and lower shaping jig drive into.

3. the method for a kind of continuous and uneven compression molding three-dimension curved surface according to claim 1 and 2, it is characterized in that, described forming tool adopts upper forming tool (1a) and lower forming tool (1b), in forming process, maintains static, and by applying external force, makes plate feeding.

4. the method for a kind of continuous and uneven compression molding three-dimension curved surface according to claim 1 and 2, it is characterized in that, described forming tool adopts upper flexible roller (7a) and lower flexible roller (7b), in forming process, upper and lower flexible roller rotates around self axis, and drives plate feeding.

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