Unequal-Channel Angular Self-Bending Extrusion Die and Method for Designing and Manufacturing the Same and Extruding Method Thereof
20230094663 · 2023-03-30
Inventors
- Guangming Zhu (Shandong, CN)
- Fanlei Min (Shandong, CN)
- Zheng Chang (Shandong, CN)
- Huiping Liu (Shandong, CN)
Cpc classification
B21C23/001
PERFORMING OPERATIONS; TRANSPORTING
B21C23/002
PERFORMING OPERATIONS; TRANSPORTING
International classification
B21C23/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Provided are an unequal-channel angular self-bending extrusion die and a method for designing and manufacturing the same and extrusion method thereof and includes following steps: designing a symmetrical streamlined extrusion die based on sine function; making the medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed on a certain plane; establishing the die cavity wall surface equation of the unequal-channel angular self-bending extrusion die; setting a working belt structure downstream the die cavity of the unequal-channel angular self-bending extrusion die.
Claims
1. A method for designing an unequal-channel angular self-bending extrusion die, comprising steps of: designing a symmetrical streamlined extrusion die based on a sine function, wherein wall surfaces of two sides of a die cavity of the extrusion die are symmetrical streamlined; making a medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed in a certain plane, to form an arched curve, wherein the arched curve remains symmetrical along an extrusion direction, has no offset at both ends of the curve and is tangent to an axis; establishing a wall surface equation of the die cavity of the unequal-channel angular self-bending extrusion die according to a medial axis of the arched curve; and setting a working belt structure downstream the die cavity of the unequal-channel angular self-bending extrusion die, with a wall surface of the working belt structure parallel to the extrusion direction.
2. The method for designing an unequal-channel angular self-bending extrusion die according to claim 1, wherein the designing a symmetrical streamlined extrusion die based on a sine function further comprises: remaining a shape of the die cavity of the extrusion die on any horizontal section to be circular, wherein a boundary curve of the die cavity of the extrusion die is described by a sine function, with a center of the medial axis as an origin and a z direction as the extrusion direction, wherein a left boundary curve function is:
3. The method for designing an unequal-channel angular self-bending extrusion die according to claim 2, wherein the making a medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises: an Axis_trig of a twisted medial axis Axis is described based on a trigonometric function as follows:
4. The method for designing an unequal-channel angular self-bending extrusion die according to claim 2, wherein the making a medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises: an Axis_gauss of a twisted medial axis Axis is described based on a Gauss-like distribution function as follows:
Axis_gauss0=A exp(−B .Math.z.sup.2) where A, B are undetermined coefficients.
5. The method for designing an unequal-channel angular self-bending extrusion die according to claim 4, further comprises a step of: correcting Axis_gauss0 by a mathematical transformation, comprising first calculating a value of Axis_gauss0 at an end point, which is Axis_gauss0 (L/2), wherein the coefficient A is set as h+Axis_gauss0 (L/2), so as to enlarge a height of the curve by Axis_gauss (L/2) times, and then subtracting Axis_gauss0 (L/2) to obtain a corrected medial axis Axis_gauss based on the Gaussian-like distribution function, wherein the equation is described as:
Axis_gauss=(h+Axis_gauss0(L/2))exp(B.Math.z.sup.2)−Axis_gauss0(L/2) where a value of the coefficient B is an empirical value, wherein when a value of the B is 0.01, a distance from the end point of the curve to an original axis is able to be controlled within 0.01 mm.
6. The method for designing an unequal-channel angular self-bending extrusion die according to claim 4, wherein the establishing a wall surface equation of the die cavity of the unequal-channel angular self-bending extrusion die comprises: describing a wall surface of the die cavity as a curved surface equation of:
7. A method for manufacturing an unequal-channel angular self-bending extrusion die, wherein the unequal-channel angular self-bending extrusion die is manufactured based on the method for designing an unequal-channel angular self-bending extrusion die according to claim 1.
8. An unequal-channel angular self-bending extrusion die, manufactured by the method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 7, comprising: a die body, wherein the die body comprises a die cavity and a working belt structure, the die cavity has a self-bending outlet, with the working belt structure extending along the self-bending outlet of the die cavity, and the working belt structure is integrally connected to the die cavity; and the wall surface of the die cavity is described as a curved surface equation of:
9. The unequal-channel angular self-bending extrusion die according to claim 8, wherein the equation of the medial axis of the die cavity is described based on the trigonometric function as follows:
Axis_gauss=(h+Axis_gauss0(L/2))exp(B.Math.z.sup.2)−Axis_gauss0(L/2) where the value of the coefficient B is an empirical value, wherein when the value of the B is 0.01, the distance from the end point of the curve to the original axis is able to be controlled within 0.01 mm; where Axis is Axis_trig or Axis_gauss, respectively.
10. The method for designing an unequal-channel angular self-bending extrusion die according to claim 5, wherein the establishing a wall surface equation of the die cavity of the unequal-channel angular self-bending extrusion die comprises: describing a wall surface of the die cavity as a curved surface equation of:
11. The method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 7, wherein the designing a symmetrical streamlined extrusion die based on a sine function further comprises: remaining a shape of the die cavity of the extrusion die on any horizontal section to be circular, wherein a boundary curve of the die cavity of the extrusion die is described by a sine function, with a center of the medial axis as an origin and a z direction as the extrusion direction, wherein a left boundary curve function is:
12. The method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 11, wherein the making a medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises: an Axis_trig of a twisted medial axis Axis is described based on a trigonometric function as follows:
13. The method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 11, wherein the making a medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises: an Axis_gauss of a twisted medial axis Axis is described based on a Gauss-like distribution function as follows:
Axis_gauss0=A exp(−B.Math.z.sup.2) where A, B are undetermined coefficients.
14. The method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 13, further comprises a step of: correcting Axis_gauss0 by a mathematical transformation, comprising first calculating a value of Axis_gauss0 at an end point, which is Axis_gauss0 (L/2), wherein the coefficient A is set as h+Axis_gauss0 (L/2), so as to enlarge a height of the curve by Axis_gauss (L/2) times, and then subtracting Axis_gauss0 (L/2) to obtain a corrected medial axis Axis_gauss based on the Gaussian-like distribution function, wherein the equation is described as:
Axis_gauss=(h+Axis_gauss0(L/2))exp(B.Math.z.sup.2)−Axis_gauss0(L/2) where a value of the coefficient B is an empirical value, wherein when a value of the B is 0.01, a distance from the end point of the curve to an original axis is able to be controlled within 0.01 mm.
15. The method for manufacturing an unequal-channel angular self-bending extrusion die according to claim 13, wherein the establishing a wall surface equation of the die cavity of the unequal-channel angular self-bending extrusion die comprises: describing a wall surface of the die cavity as a curved surface equation of:
Description
BRIEF DESCRIPTION OF DRAWINGS
[0042] With the purpose of more clearly describing the technical solutions in the specific embodiments of the present disclosure or in the prior art, a brief introduction to the drawings that need to be used in the description of the specific embodiments or the prior art will follow. Obviously, the drawings hereunder show some embodiments of the present disclosure. It should be understood that a person ordinarily skilled in the art still could obtain other drawings according to these drawings, without any inventive effort.
[0043]
[0044]
[0045]
[0046] Reference Signs: 1—Die body; 11—Die cavity; 12—Working belt structure; 2—Die cavity geometry; 21—Medial axis of symmetrical extrusion die; 22—Left contour line of symmetrical extrusion die; 23—Right contour line of symmetrical extrusion die; 24—Medial axis of the unequal-channel angular self-bending extrusion die; 25—Left contour line of the unequal-channel angular self-bending extrusion die; 26—Right contour line of the unequal-channel angular self-bending extrusion die; 31—Extruded bent profile.
DETAILED DESCRIPTION OF EMBODIMENTS
[0047] The technical solutions of the present disclosure will be described below clearly and completely in connection with examples. It is apparent that the examples to be described are some, but not all of the examples of the present disclosure. All the other examples obtained by those of ordinary skill in the art in light of the examples of the present disclosure without inventive efforts will fall within the scope of the present disclosure as claimed.
[0048] It should be noted that this embodiment combines a forming process of the profile, in which extrusion and bending is integrated, with a streamlined extrusion die, and proposes a new process of unequal-channel angular self-bending extrusion forming, enabling metal to flow unevenly in the die cavity, so as to directly extrude the bent profile, in a manner of designing a streamlined extrusion die structure with a twisted medial axis.
[0049] As shown in
[0050] The method for designing an unequal-channel angular self-bending extrusion die provided by this embodiment comprises the following steps: designing a symmetrical streamlined extrusion die based on sine function, wherein the wall surfaces of two sides of the die cavity 11 of the extrusion die are symmetrical streamlined; making the medial axis of the die cavity 11 of the symmetrical streamlined extrusion die twisted and deformed in a certain plane, to form an arched curve, wherein the arched curve remains symmetrical along the extrusion direction, and has no offset at both ends of the curve and is tangent to the axis; establishing a die cavity 11 wall surface equation of the unequal-channel angular self-bending extrusion die according to the medial axis of the arched curve; setting a working belt structure 12 downstream the die cavity 11 of the unequal-channel angular self-bending extrusion die, with the wall surface of the working belt structure 12 parallel to the extrusion direction; designing and forming an unequal-channel angular self-bending extrusion die, wherein after the metal flow passes through the unequal-channel angular self-bending extrusion die, the die cavity 11 of the unequal-channel angular self-bending extrusion die is used to control the extrusion speed to be linearly distributed, so as to directly form bent parts by extrusion, as a result of which the profile is not subject to lateral moment, thereby cross-sectional deformation is reduced or prevented on the outer side surface of the profile, and the flow of the metal during the extrusion process is smoother than that of the conventional stepped extrusion die, and the extrusion load is reduced, alleviating the technical problems of springback, wrinkling and cross-sectional deformation during bending process of the profile in the prior art, and reducing the load during extrusion.
[0051] The specific design steps as shown in
[0052] The function of the right contour line 23 of the symmetrical extrusion die is:
[0053] where R is the diameter of the inlet die hole, that is, the diameter of the blank; r is the diameter of the outlet die hole, that is, the diameter of the bar, and L is the height of the die cavity 11.
[0054] In a preferred embodiment of the present disclosure, the making the medial axis of the die cavity 11 of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises: the Axis_trig of the twisted medial axis Axis is described as follows based on the trigonometric function:
[0055] where h is the maximum offset distance of the twisted and deformed medial axis curve;
[0056] In a preferred embodiment of the present disclosure, the making the medial axis of the die cavity 11 of the symmetrical streamlined extrusion die twisted and deformed in a certain plane further comprises:
[0057] the Axis_gauss of the twisted medial axis Axis is described as follows based on the Gauss-like distribution function:
Axis_gauss0=A exp(−B.Math.z.sup.2)
[0058] where A, B are undetermined coefficients;
[0059] wherein the twisted medial axis is the medial axis 24 of unequal-channel angular self-bending extrusion die.
[0060] In a preferred embodiment of the present disclosure, it further comprises a step of:
[0061] correcting Axis_gauss0 by mathematical transformation, including first calculating the value of Axis_gauss0 at the end point, which is Axis_gauss0 (L/2), wherein the coefficient A is set as h+Axis_gauss0 (L/2), so as to enlarge the curve height by Axis_gauss (L/2) times and then subtracting Axis_gauss0 (L/2) to obtain the corrected medial axis Axis_gauss based on the Gaussian-like distribution function. The equation is described as:
Axis_gauss=(h+Axis_gauss0(L/2))exp(B.Math.z.sup.2)−Axis_gauss0(L/2)
[0062] where the value of the coefficient B is an empirical value, when the value of B is 0.01, the distance from the end point of the curve to the original axis can be controlled within 0.01 mm.
[0063] In a preferred embodiment of the present disclosure, the establishing the die cavity 11 wall surface equation of the unequal-channel angular self-bending extrusion die comprises a step of:
[0064] describing the wall surface of die cavity 11 as the curved surface equation of:
[0065] where Axis is Axis_trig or Axis_gauss, respectively.
[0066] As shown in
[0067] the function Line_right of the right contour line 23 of the symmetrical extrusion die is described as:
[0068] where the wall surface equation of the symmetrical streamlined die cavity 11 is described as:
[0069] where the maximum offset height of the medial axis 24 of the unequal-channel angular self-bending extrusion die is h=10 mm, and the Axis_trig of the medial axis 24 of the unequal-channel angular self-bending extrusion die is described by trigonometric function as:
[0070] Another description of Axis_gauss of the medial axis 24 of the unequal-channel angular self-bending extrusion die based on the Gauss-like distribution function is:
Axis_gauss=(10+0.1832)exp(0.01.Math.z.sup.2)−0.1832
[0071] After the equation Axis of the medial axis 24 of the unequal-channel angular self-bending extrusion die is determined, that is, after the medial axis of the symmetrical streamlined die cavity 11 is twisted and deformed, the other parameters of the die cavity 11 structure are translated accordingly, that is, the shape of the cavity before the deformation remains circular along a certain horizontal section. After deformation, on a plane perpendicular to the extrusion direction, the distance between each of the points on the wall surface of the die cavity 11 and the medial axis 24 of the unequal-channel angular self-bending extrusion die is equal, that is, the section of die cavity 11 is circular, while the position of the center of the circle is different from the original one, which can determine the curved surface equation of the unequal-channel angular die cavity 11 wall surface formed by the left contour line 25 of the unequal-channel angular self-bending extrusion die and the right contour line 26 of the unequal-channel angular self-bending extrusion die, according to the structure principle of the unequal-channel angular self-bending extrusion die, wherein the curved surface equation formulated by Axis_trig of the unequal-channel angular die cavity 11 wall surface of the medial axis 24 of the unequal-channel angular self-bending extrusion die is:
[0072] wherein the curved surface equation formulated by Axis_gauss of the unequal-channel angular die cavity 11 wall surface of the medial axis 24 of the unequal-channel angular self-bending extrusion die is:
[0073] Furthermore, upon determination of the unequal-channel angular extrusion die cavity 11, a working belt structure 12 with certain length is set additionally downstream it. The length of the working belt structure 12 may be selected as t=6 mm. The wall surface of the working belt structure 12 is parallel to the extrusion direction.
[0074] This embodiment provides a method for manufacturing an unequal-channel angular self-bending extrusion die, which is manufactured based on the method for designing the unequal-channel angular self-bending extrusion die; and this embodiment, based on the designing method aforementioned, is manufactured mechanically using the curved surface equation of the unequal-channel angular die cavity 11 wall surface, thereby an unequal-channel angular self-bending extrusion die can be manufactured.
[0075] The present embodiment provides an unequal-channel angular self-bending extrusion die, which is manufactured by the method for manufacturing the unequal-channel angular self-bending extrusion die, comprising: a die body 1;
[0076] wherein the die body 1 comprises the die cavity 11 and the working belt structure 12, the die cavity 11 has a self-bending outlet and the working belt structure 12 extends along the self-bending outlet of the die cavity 11, and the working belt structure 12 is integrally connected with the die cavity 11; and the wall surface of the die cavity 11 is a curved surface equation of:
[0077] where R is the diameter of the inlet die hole of the die cavity 11, that is, the diameter of the blank; r is the diameter of the outlet die hole of the die cavity 11, that is, the diameter of the bar; L is the height of the die cavity 11, and Axis is the equation of the medial axis of the die cavity 11.
[0078] In the preferred embodiment of the present disclosure, the medial axis equation of the die cavity 11 is described as follows based on trigonometric function:
[0079] where h is the maximum offset distance of the twisted and deformed medial axis curve;
[0080] or the medial axis equation of the die cavity 11 is described based on the Gaussian-like distribution function as,
Axis_gauss=(h+Axis_gauss0(L/2))exp(B.Math.z.sup.2)−Axis_gauss0(L/2)
[0081] where the value of the coefficient B is an empirical value, when the value of B is 0.01, the distance from the end point of the curve to the original axis can be controlled within 0.01 mm;
[0082] where Axis is Axis_trig or Axis_gauss, respectively.
[0083] In this embodiment, adding the working belt structure 12 can extend the deformation coordination of metal, reduce the difference in metal flow speed in the channel of the working belt structure 12, and reduce the uneven level of the extrusion speed, hence reducing the degree of bending. Therefore, adding the working belt structure 12 can be used to design the extrusion of profiles with different bending curvatures.
[0084] This embodiment provides an extrusion method based on the unequal-channel angular self-bending extrusion die, which comprises the following steps: placing metal in the die cavity 11 of the die body 1; controlling the speed of extruding the metal at the inlet of the die cavity 11; based on the self-bending outlet of the die cavity 11 and the working belt structure 12, extruding metal to form a bent profile with a preset curvature, thereby forming an extruded bent profile 31.
[0085] In this embodiment, the process parameters of the extrusion method comprise: the material of the blank is AA6063 aluminum alloy, the extrusion ratio λ=25, the extrusion speed v=10 mm/s, the preheating temperature of the blank is 450° C., and the preheating temperature of the extrusion barrel is 470° C., the preheating temperature of the extrusion die is 480° C.; the shear friction model is applied between the blank and the die, with the friction factor being set to 0.7, and the Coulomb friction model is applied between the blank and the working belt, with the friction factor being set to 0.3; according to symmetry, simulation is performed on 1/2 of the entire model, and all components are divided into tetrahedral elements, the mesh number of blank is 30,000, and the displacement step size is 0.2 mm.
[0086] As shown in
[0087] As shown in
[0088] It should be noted that the “left”, “right” and “z direction” mentioned in the present disclosure all relate to the position of the unequal-channel angular self-bending extrusion die when it is working, which is only intended for a smooth description, and shall not impose limitations on the present disclosure.
[0089] Finally, it should be noted that the above embodiments are merely intended to illustrate the technical solutions of the present disclosure, but not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that the technical solutions disclosed in the foregoing embodiments may still be modified, or some or all of the technical features therein may be replaced with equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present disclosure.