CN110193556B - Die for manufacturing stretch-bending section bar and manufacturing method thereof - Google Patents
Die for manufacturing stretch-bending section bar and manufacturing method thereof Download PDFInfo
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- CN110193556B CN110193556B CN201810162280.4A CN201810162280A CN110193556B CN 110193556 B CN110193556 B CN 110193556B CN 201810162280 A CN201810162280 A CN 201810162280A CN 110193556 B CN110193556 B CN 110193556B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
- B21D37/10—Die sets; Pillar guides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/92—Making other particular articles other parts for aircraft
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D7/00—Bending rods, profiles, or tubes
- B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
- B21D7/022—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment over a stationary forming member only
- B21D7/0225—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment over a stationary forming member only using pulling members
Abstract
The invention relates to a die for manufacturing stretch-bending section bars and a manufacturing method thereof. The method comprises the steps of determining a stretch bending process of a profile blank for forming the profile and a profile of a die for forming the profile, which is in contact with the profile blank, according to the configuration of the expected profile, and analyzing the stretch bending process of the profile blank and the profile of the die to obtain a profile blank easy-fracture area and a non-profile blank easy-fracture area on the profile, wherein the friction force between the profile blank and the die is large in the profile blank easy-fracture area, wherein different measures for reducing the friction force are implemented for the profile blank easy-fracture area and the non-profile blank easy-fracture area on the die, so that the friction force of the profile blank and the die at the profile blank easy-fracture area and the non-profile blank easy-fracture area is approximately the same. Therefore, the defects that in the traditional section bar stretch bending process, the local extension of the section bar blank is uneven, and finally the integral stretch bending is not in place, the local resilience is serious or the section bar blank is broken are overcome.
Description
Technical Field
The invention relates to a die for manufacturing a stretch-bending section and a manufacturing method of the die.
Background
In the prior art, it is common technical means to manufacture profiles or parts by means of a stretch-bending process. In particular, in the manufacture of aircraft parts, frame flanges, stringers and other parts are large-sized, variable-curvature extruded profile bends having large relative bending radii, and stretch-bending forming processes are generally used.
In the stretch-bending of profiles, one or both ends of a profile blank, for example of a metal material, are usually fixed and drawn, a die having a corresponding profile being used during drawing, depending on the desired profile configuration, the profile blank being given a specific shape by deforming it by direct contact with the die.
When the section blank is subjected to stretch bending, the stress states of all parts in the deformation area are different. Specifically, the portion that is not deformed in the middle of the cross section is called a neutral layer; the material outside the neutral layer is under the action of tensile stress to generate elongation deformation; the metal inside the neutral layer is subjected to compressive stress to generate compressive deformation. Because the stress and strain directions of the materials on the two sides of the neutral layer are opposite, after the load is removed, the elastic deformation recovery directions of the materials on the two sides of the neutral layer are opposite, and the elastic recovery of different degrees is caused. Although the stretch-bending deformation is limited to a localized area of material, the spring action can affect the accuracy of the bending member. In practice, the springing influence factors are many and are difficult to control, and the precision problem of the stretch-bending part caused by springing is always the key of stretch-bending forming production.
In the stretch bending process of the section bar by using the die, because the section bar blank is in direct contact with the die, the friction force of a partial area is large when the section bar blank is deformed by stretch bending, the material is prevented from flowing, and finally the section bar is broken, the part is also called as an easy-to-break part, and the area of the die corresponding to the part is called as an easy-to-break area of the section bar. Therefore, the common solution is to directly coat lubricating oil between the die and the profile blank, reduce the resistance generated by sliding friction in the stretch bending process by reducing the friction coefficient, promote the material to flow and improve the forming effect.
However, this solution has two main drawbacks: the lubricating effect of the lubricating oil is not ideal enough, and the large complex section part still cannot be bent in place and has large resilience; in the process of bending the section, the friction force at different parts is different, so that the elongation is uneven, the middle part, the two ends and the jaw of the die are easy to break, and the resilience of parts is larger. The main causes of these defects are mainly twofold. On one hand, the friction force is still large and the material is still prevented from flowing only by lubricating oil; on the other hand, in the process of stretch bending of the section bar, the friction force of different areas is different, so that the blank is unevenly extended, the local elongation is too large, and further the blank is broken, and the elongation of the rest parts is too small, so that the resilience is serious.
Therefore, in the conventional section stretch bending process, in order to prevent the fracture, the elongation is usually set according to an empirical value, and for the part springback caused by too small elongation, the subsequent manual shaping on a die is mainly relied on, and the part which is not formed in place is further shaped, and finally the configuration requirement of the part is achieved. However, the manual correction of a large amount of shapes is not only high in working strength, but also can generate knocking marks on the surface of the part and affect the surface quality of the part.
Disclosure of Invention
Based on the prior art, the invention provides an optimized manufacturing method of a die for manufacturing a stretch-bending section and an optimized die for manufacturing the stretch-bending section, so that the defects that in the traditional section stretch-bending process, the section blank locally extends unevenly, and finally the integral stretch-bending is not in place, the local resilience is serious or the section blank is broken are overcome.
In order to achieve the above object, in a manufacturing method of a die for manufacturing a stretch-bent profile according to the present invention, determining the stretch bending process of the section blank for forming the section and the contact profile of the mould for forming the section and the section blank according to the desired configuration of the section, according to the stretch bending process of the profile blank and the profile analysis of the die, a profile blank easy-fracture area and a non-profile blank easy-fracture area on the profile are obtained, wherein the friction between the profile blank and the die is greater in the region of the profile blank which is susceptible to fracture, wherein different measures for reducing the friction force are implemented for the easy-to-break area of the section blank and the easy-to-break area of the non-section blank on the die, so that the friction force of the profile blank and the die at the profile blank easy fracture area and the non-profile blank easy fracture area is approximately the same.
According to a preferred embodiment of the invention, a rolling friction measure, for example a first cylindrical roller, is applied in the region of the profile blank that is susceptible to fracture. Lubricating oil may additionally be applied to the first cylindrical roller.
According to a preferred embodiment of the invention, a sliding friction measure, for example a lubricant, is applied to the easily breakable regions of the non-profiled blank.
According to a preferred embodiment of the invention, a rolling friction measure, for example a second cylindrical roller, can also be applied to the region of the non-profile blank that is susceptible to fracture, wherein the friction coefficient of the rolling friction measure is greater than the friction system of the rolling friction measure applied to the region of the profile blank that is susceptible to fracture. For example, the two may be cylindrical rollers made of different materials and thus have different coefficients of friction.
According to a preferred embodiment of the present invention, the easily breakable areas of the profile blank and the easily breakable areas of the non-profile blank on the contour of the die are obtained based on an analysis of the stress state of the profile blank.
The invention also proposes a die for producing stretch-bent profiles, having a contour which is in contact with a profile blank for forming the profile and corresponds to the desired profile configuration, the contour having a profile blank region which is susceptible to fracture and a non-profile blank region which is susceptible to fracture, wherein the friction between the profile blank and the die is greater in the profile blank region which is susceptible to fracture, wherein different measures for reducing the friction are carried out on the die in the profile blank region which is susceptible to fracture and in the non-profile blank region which is susceptible to fracture, so that the friction of the profile blank and the die at the profile blank region which is susceptible to fracture and in the non-profile blank region are approximately the same.
According to a preferred embodiment of the invention, rolling friction means, for example a first cylindrical roller, are provided in the region of the easy-to-break section of the profile blank. Lubricating oil may additionally be applied to the first cylindrical roller.
According to a preferred embodiment of the invention, a sliding friction measure, for example a lubricant, is applied to the easily breakable regions of the non-profiled blank.
According to a preferred embodiment of the invention, a rolling friction measure, for example a second cylindrical roller, can also be applied to the region of the non-profile blank that is susceptible to fracture, wherein the friction coefficient of the rolling friction measure is greater than the friction system of the rolling friction measure applied to the region of the profile blank that is susceptible to fracture. For example, the two may be cylindrical rollers made of different materials and thus have different coefficients of friction.
The invention overcomes the problem of uneven local extension of the section blank in the traditional section stretch bending process, and avoids the defects of incomplete integral stretch bending, fracture or serious springback.
Drawings
In the drawings, there are shown advantageous embodiments according to the invention. In the drawings:
fig. 1 shows a flow chart of a method for manufacturing a die for manufacturing stretch-bent profiles according to the invention;
fig. 2 shows a schematic view of a die for manufacturing stretch-bent profiles according to the invention;
fig. 3 shows a schematic illustration of the friction-reducing measures according to the invention in the region of the easy-to-break area of the profile blank; and
fig. 4 shows a schematic view of the manufacture of a stretch-bent profile using a die for the manufacture of a stretch-bent profile according to the invention.
Detailed Description
Hereinafter, a manufacturing method of a die for manufacturing a stretch-bent profile and a specific embodiment of the die for manufacturing a stretch-bent profile according to the present invention will be described in detail with reference to the accompanying drawings. The following is given only by way of preferred embodiments according to the invention, on the basis of which other ways of implementing the invention may be conceived by those skilled in the art, which also fall within the scope of the invention.
Referring to fig. 1, in the manufacturing method of the die for manufacturing a stretch-bent profile according to the present invention, first, a stretch-bending process of a profile blank for constituting the profile and a profile of the die for constituting the profile in contact with the profile blank are determined according to a configuration of a desired profile, and second, a profile blank breakable area and a non-profile blank breakable area on the profile are obtained according to the stretch-bending process of the profile blank and a profile analysis of the die, wherein a frictional force between the profile blank and the die is large in the profile blank breakable area. Finally, different measures for reducing the friction force are implemented for the easy-to-break area of the profile blank and the easy-to-break area of the non-profile blank on the die, so that the friction force of the profile blank and the die at the easy-to-break area of the profile blank and the easy-to-break area of the non-profile blank are approximately the same.
In particular, rolling friction measures, such as cylindrical rollers, are applied to the region of the profile blank that is susceptible to fracture, while sliding friction measures, such as lubricating oil, are applied to the region of the non-profile blank that is susceptible to fracture. Lubricating oil can be additionally applied to the rolling friction measure of the easy-to-break area of the profile blank. It is also possible to apply, for example, a cylindrical roller rolling friction measure to the non-profile blank region which is susceptible to fracture, but the coefficient of friction of the rolling friction measure is greater than the coefficient of friction of the rolling friction measure applied to the profile blank region which is susceptible to fracture.
In particular, the areas of the profile blank that are susceptible to fracture and the areas of the non-profile blank that are susceptible to fracture can be evaluated on the basis of defects and/or stress states at different points of the profile blank during the stretch-bending of the profile.
Therefore, differential friction design is carried out on different parts of the die, local friction coefficients are changed as required, the difference of the friction forces of different parts in the stretch bending process is reduced, all parts of the section bar are enabled to extend uniformly, the best stress state is achieved integrally, and the defects of breakage, resilience and the like are reduced.
Fig. 2 shows a schematic view of a die 1 for manufacturing a stretch-bent profile according to the present invention obtained on the basis of the above manufacturing method of a die for manufacturing a stretch-bent profile according to the present invention. Wherein the die 1 has a contour corresponding to the desired profile configuration in contact with the profile blank 2 for forming the profile, the contour having a profile blank easy-to-break area 10 and a non-profile blank easy-to-break area 11, wherein the friction between the profile blank 2 and the die 1 is greater in the profile blank easy-to-break area 10 and the friction between the profile blank 2 and the die 1 is smaller in the non-profile blank easy-to-break area 11. According to the invention, different measures for reducing the friction are implemented in the easy-to-break area 10 of the profile blank and the easy-to-break area 11 of the non-profile blank, so that the friction of the profile blank 2 and the friction of the die 1 at the easy-to-break area 10 of the profile blank and the easy-to-break area 11 of the non-profile blank are approximately the same.
The friction-reducing measure implemented in the region of the easy-to-break 10 of the profile blank can be, for example, a rolling friction measure, in particular a first cylindrical roller 101, as shown in fig. 3, whereby the friction between the profile blank 2 and the die 1 is reduced. Additionally, lubricating oil may also be applied to the first cylindrical roller 101, thereby further reducing friction.
In the region of the non-profiled blank that is susceptible to fracture 11, sliding friction measures, such as for example the application of lubricating oil, can be applied. It is also possible to apply a rolling friction measure, for example a second cylindrical roller, also in the non-profile-blank region 11, but with a higher coefficient of friction than the rolling friction measure applied in the profile-blank region 10.
Fig. 4 shows a schematic view of the manufacture of a stretch-bent profile using a die for the manufacture of a stretch-bent profile according to the invention, in which both ends of a profile blank 2 are fixed and stretched in opposite directions, and subsequently brought into contact with the die 1, in particular with the profile blank breakable zone 10 and the non-profile blank breakable zone 11 of the die 1, to be deformed in order to obtain the desired configuration.
While the invention has been illustrated and described herein in connection with preferred embodiments, it is evident that various modifications, substitutions and additions may be made thereto, all within the broad scope contemplated by the claims.
Claims (13)
1. A method for producing a die for producing a stretch-bent profile, wherein a stretch-bending process for a profile blank forming the profile and a contour of the die for forming the profile, which contour is in contact with the profile blank, are determined according to a desired profile of the profile, according to the stretch bending process of the profile blank and the profile analysis of the die, a profile blank easy-fracture area and a non-profile blank easy-fracture area on the profile are obtained, wherein the friction between the profile blank and the die is greater in the region of the profile blank which is susceptible to fracture, characterized in that different measures for reducing the friction force are implemented for the easily breakable area of the profile blank and the easily breakable area of the non-profile blank on the die, so that the friction force of the profile blank and the die at the profile blank easy fracture area and the non-profile blank easy fracture area is approximately the same.
2. A method of manufacture according to claim 1, characterized in that a rolling friction measure is applied in the region of the profile blank which is susceptible to fracture.
3. The manufacturing method according to claim 2, wherein the rolling friction means is a first cylindrical roller.
4. A manufacturing method according to claim 3, wherein a lubricating oil is applied to the first cylindrical roller.
5. A method of manufacture according to any of the preceding claims 1 to 4, characterized in that a sliding friction measure is applied in the region of the non-profile blank susceptible to fracture.
6. A method of manufacture according to claim 5, wherein a lubricating oil is applied to the breakable areas of the non-profile blank.
7. A method of manufacturing according to claim 2 or 3, wherein a second cylindrical roller is applied to the breakable zone of the non-profiled blank, wherein the second cylindrical roller has a higher coefficient of friction than the first cylindrical roller.
8. A method of manufacturing according to any one of the preceding claims 1 to 4, characterized in that the areas of easy-to-break profile blank and the areas of easy-to-break non-profile blank on the profile are obtained on the basis of an analysis of the stress state of the profile blank.
9. A die for producing stretch-bent profiles, having a profile which is in contact with a profile blank for forming the profile and which corresponds to the desired profile configuration of the profile, the profile having a profile blank region of easy fracture and a non-profile blank region of easy fracture, wherein the friction between the profile blank and the die is greater in the profile blank region of easy fracture, characterized in that different measures for reducing the friction are implemented on the die for the profile blank region of easy fracture and for the non-profile blank region of easy fracture, so that the friction of the profile blank and of the die at the profile blank region of easy fracture and at the non-profile blank region of easy fracture are approximately the same.
10. A die as claimed in claim 9, wherein a first cylindrical roller is provided in the region of the profile blank susceptible to fracture.
11. The die of claim 10, wherein a lubricating oil is applied to said first cylindrical roller.
12. A die according to any one of claims 9 to 11, wherein a lubricating oil is applied to the breakable areas of the non-profile blank.
13. A die according to any one of claims 10 to 11, wherein a second cylindrical roller is provided in the region of the non-profile blank susceptible to fracture, wherein the second cylindrical roller has a higher coefficient of friction than the first cylindrical roller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810162280.4A CN110193556B (en) | 2018-02-27 | 2018-02-27 | Die for manufacturing stretch-bending section bar and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810162280.4A CN110193556B (en) | 2018-02-27 | 2018-02-27 | Die for manufacturing stretch-bending section bar and manufacturing method thereof |
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| Publication Number | Publication Date |
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| CN110193556A CN110193556A (en) | 2019-09-03 |
| CN110193556B true CN110193556B (en) | 2021-01-26 |
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| CN201810162280.4A Active CN110193556B (en) | 2018-02-27 | 2018-02-27 | Die for manufacturing stretch-bending section bar and manufacturing method thereof |
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Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4269053A (en) * | 1979-07-25 | 1981-05-26 | Rockwell International Corporation | Method of superplastic forming using release coatings with different coefficients of friction |
| US5819572A (en) * | 1997-07-22 | 1998-10-13 | General Motors Corporation | Lubrication system for hot forming |
| US20040129052A1 (en) * | 2003-01-06 | 2004-07-08 | Krajewski Paul Edward | Method of reducing cycle time for metal forming |
| JP4850570B2 (en) * | 2006-04-14 | 2012-01-11 | 新日本製鐵株式会社 | Butt weld metal plate |
| CN102151728B (en) * | 2011-05-09 | 2012-07-25 | 江苏同力机械有限公司 | Cold bending forming process for camber beam of car body of passenger car |
| CN102366770B (en) * | 2011-10-10 | 2013-11-20 | 上海交通大学 | Design method of stretch bending loading trace of novel stretch bender |
| CN107073860A (en) * | 2014-08-28 | 2017-08-18 | 戴维·布罗德赫德 | Punch die or drift for diel |
| CN106944545A (en) * | 2017-03-25 | 2017-07-14 | 亿森（上海）模具有限公司 | Moulding face different coefficients of friction and controllable forming method |
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| CN110193556A (en) | 2019-09-03 |
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