CN114101474A - Two-pass forming processing method for convex hull of module backboard - Google Patents
Two-pass forming processing method for convex hull of module backboard Download PDFInfo
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- CN114101474A CN114101474A CN202010901629.9A CN202010901629A CN114101474A CN 114101474 A CN114101474 A CN 114101474A CN 202010901629 A CN202010901629 A CN 202010901629A CN 114101474 A CN114101474 A CN 114101474A
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- 238000003672 processing method Methods 0.000 title claims abstract description 14
- 238000007493 shaping process Methods 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims description 12
- 230000007704 transition Effects 0.000 claims description 8
- 239000000463 material Substances 0.000 description 11
- 238000005336 cracking Methods 0.000 description 9
- 239000002994 raw material Substances 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000003044 adaptive effect Effects 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
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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
- B21D35/00—Combined processes according to or processes combined with methods covered by groups B21D1/00 - B21D31/00
- B21D35/002—Processes combined with methods covered by groups B21D1/00 - B21D31/00
Abstract
The invention discloses a two-pass forming processing method for a convex hull of a module backboard, which comprises a first pass of preforming and a second pass of shaping into a designed shape, wherein the first pass adopts a convex hull design center as a central axis and adopts a rotary curved surface stamping and forming mode of peak-valley-peak shape at two sides of a middle valley shape; along the central axis, the rotating curved surface comprises a valley-shaped first section of circular arc which is centrosymmetric relative to the central axis, a peak-shaped second section of circular arc, a slope-shaped third section of circular arc and a fourth section of circular arc which is connected with the surface of the back plate, wherein the peak-shaped second section of circular arc, the slope-shaped third section of circular arc and the fourth section of circular arc are outward in sequence; the height H1 between the bottom of the first arc and the back plate is 1/2H, and H is the design height of the convex hull; the height H2 of the arc top of the second section of arc from the back plate is 3/4H, the distance Rc of the arc top of the second section of arc from the center line is 1/2Rb, and Rb is the radius of the lower table surface designed by the convex hull; the radius r6 of the second section of circular arc is 1/4H, and the radius r5 of the first section of circular arc is Rb ^2/(8r6) -r 6/2; taking the distance between the fourth arc and the central axis at the connecting back plate as the radius Rb2 of the bottom forming zone, the radius Rb2 satisfies the following conditions: rb2-Rb 1+ Δ R, Δ R being the preform radius increment.
Description
Technical Field
The invention relates to a forming processing method of a module backboard convex hull, in particular to a two-pass forming processing method of the module backboard convex hull, which improves the formability and reduces the cracking incidence.
Background
The module backboard is the most important metal structural member in the liquid crystal television and is used for supporting various electronic components of the liquid crystal module. The overall design of the sheet metal part is large-size, flat (few curved surfaces) and shallow-stamped, the local forming characteristic is that a large number of convex hulls and reinforcing ribs are formed, and the sheet metal part is mainly used as a mounting base of various electronic components, as shown in fig. 1, in the prior art, a typical convex hull is designed to be in a circular truncated cone shape, the radius of an upper table surface is Ru, the radius of a lower table surface is Rb, the height of the convex hull is H, an inclination angle is a, and upper and lower circular-corner radii r1 and r2 are in transition. In general, the height H of the convex hull is 0-30 mm, and the inclination angle a is 45-60 degrees.
On the other hand, the cracking of the convex hull is a main risk point in the forming process of the module backboard, and due to the design characteristics of the convex hull, the traditional forming process generally adopts two-pass forming, wherein the first-pass pre-forming is semispherical, and the second-pass shaping is the design shape, as shown in fig. 2, and two lines in the drawing respectively represent the structural profiles of the first-pass and the second-pass. The semi-spherical surface shape is mostly composed of two sections of circular arcs r3 and r4, the height of the semi-spherical surface shape is approximately equal to the height H of the convex hull, and the radius (including the circular arc chamfer section) Rb2 of the lower table surface is slightly larger than the Rb1 of the lower table surface (including the circular arc section) designed by the convex hull.
Although the existing module backboard raw material adopts mild steel (with yield strength of about 150-160 MPa) with low yield strength and good formability, convex hull cracking still often occurs. Especially in order to solve the problem of strength and rigidity of the whole structure of the television, part of the module back plates are made of materials with higher strength, if the yield strength reaches 200MPa, the risk of cracking during convex hull forming processing is increased sharply, and the stability of the module back plate stamping forming processing production is greatly influenced.
In addition, in consideration of the arrangement of the convex hull design and the dimensional accuracy requirement after the formation of the module back plate, the first pre-formation of the convex hull formation is not suitable to be too large, namely the difference of Rb2-Rb1 is not suitable to be too large. The large pre-forming certainly provides a better basis for the formability of the second pass shaping of the convex hull, but the material flowing into the convex hull to participate in forming is too much, so that the forming of the adjacent convex hull is influenced, the important point easily causes the problems of large integral internal stress and uneven distribution of the module backboard, and the dimensional precision such as warping easily occurs on the whole.
Disclosure of Invention
The invention aims to provide a two-pass forming processing method for a convex hull of a module backboard, which can improve the formability and reduce the cracking rate.
The technical problem to be solved can be implemented by the following technical scheme.
A two-pass forming processing method for a module backboard convex hull comprises a first pass of pre-forming and a second pass of shaping into a designed shape, wherein the second pass of shaping processing is carried out after the first pass of pre-forming, and the design of the molded surface of a shaping die is the same as that of an original convex hull; the first pass of the preforming adopts the following forming method:
taking the design center of an original convex hull as a central axis, and stamping and forming a rotary curved surface according to a 'peak-valley-peak' shape with a 'valley' shape in the middle and two peak-peak shapes on two sides;
the rotating curved surface comprises a valley-shaped first section of circular arc, a peak-shaped second section of circular arc, a slope-shaped third section of circular arc and a fourth section of circular arc, wherein the valley-shaped first section of circular arc is symmetrical relative to the center axis, and the peak-shaped second section of circular arc, the slope-shaped third section of circular arc and the fourth section of circular arc are sequentially outward;
and the number of the first and second electrodes,
(1) the arc bottom of the first arc is positioned on the central axis, the height H1 between the arc bottom and the plane where the surface of the back plate is positioned is 1/2H, and H is the design height of the convex hull; the height H2 between the arc top of the second section of arc and the plane where the surface of the back plate is located is 3/4H, the distance Rc between the arc top of the second section of arc and the center line is 1/2Rb, and the Rb is the design radius of the lower table surface of the convex hull without the arc chamfer;
(2) the radius r6 of the second section of circular arc is 1/4H, and the radius r5 of the first section of circular arc is Rb 2/(8r6) -r 6/2;
(3) taking the distance from the central axis at the joint of the fourth circular arc and the surface of the connecting back plate as the radius Rb2 of the bottom forming zone, the radius Rb2 satisfies the following conditions: rb2 ═ Rb1+ Δ R, where Δ R is the preform radius increment and Rb1 is the convex hull lower plateau design radius including the rounded chamfer.
As a further improvement of the technical solution, the fourth arc is a transition fillet.
As a further improvement of the present technical solution, the radius r8 of the fourth arc is 3-4 mm.
As a further improvement of the present technical solution, the radius r7 of the third arc is set according to the existing constraint condition.
Still as the further improvement of this technical scheme, Δ R1 ~ 3 mm.
According to the technical scheme, the novel two-pass module backboard convex hull forming processing method is mainly a first-pass pre-forming processing method, on the premise of controlling material inflow, the convex hull forming cracking incidence rate and the requirement of the convex hull on the raw material forming performance are reduced, the formability of the high-strength material convex hull and the whole size precision of the module backboard are ensured, and the adaptive window of the backboard raw material is increased.
Drawings
FIG. 1 is a diagram illustrating a typical convex hull design in the prior art;
FIG. 2 is a schematic diagram of a convex hull formed in two steps in a conventional manner, wherein the convex hull is formed in a hemispherical shape in the first step and is shaped into a designed shape in the second step;
FIG. 3 is a schematic view of the design structure of the first secondary mold surface in the forming method of the present invention;
FIG. 4 is a schematic diagram of a typical convex hull design structure of a certain module backplane according to an embodiment of the present disclosure;
Detailed Description
The invention aims to provide a novel two-pass module backboard convex hull forming processing method, which is mainly a first-pass pre-forming processing method, reduces the convex hull forming cracking rate and the requirement of convex hulls on the raw material forming performance on the premise of controlling material inflow, ensures the formability of high-strength material convex hulls and the integral size precision of a module backboard, and increases the adaptive window of backboard raw materials.
In order to realize the purpose of the invention, a new forming and processing method of the back plate convex hull of the secondary module is provided, which is mainly a forming and processing method of primary preforming:
1) the convex hull forming processing is divided into two passes, wherein the first pass is pre-forming, and the second pass is shaping into a designed shape. As shown in fig. 3, the first-pass preforming process is a current rotating curved surface of a "peak-valley-peak" shape with the design center of the original convex hull as the axis, the center cross section being the middle "valley" and the two sides "peak".
2) The generatrix of the rotating curved surface consists of 4 sections of circular arcs, wherein the first section of circular arc is 'valley' from the center line, and the radius r5 is the radius of the circular arc; the second section of circular arc is a peak, the radius r6, the third section of circular arc is a hill, the radius r7, and the fourth section of circular arc is a bottom transition fillet, and the radius r 8.
3) The center of the first arc is located on the central line, and the height H1 of the valley bottom, namely the intersection point of the arc and the central line, is 1/2H (H is the design height of the convex hull); the vertex height H2 of the second arc peak is 3/4H, the radius Rc is 1/2Rb, and Rb is the design radius of the lower platform surface of the convex hull excluding the arc chamfer.
4) The radius Rb2 of the bottom forming zone is Rb1+ delta R, wherein delta R is the increment of the preformed radius, and delta R is 1-3 mm; rb1 is the convex hull lower plateau design radius including a circular arc chamfer.
5) The second section of circular arc radius r6 is 1/4H, the first section of circular arc radius r5 is Rb ^2/(8r6) -r6/2, the fourth section of circular arc radius r8 is 3-4 mm, and the third section of circular arc radius r7 is set according to the existing constraint conditions.
6) And performing second-pass shaping processing after the first-pass preforming, wherein the design of the molded surface of the shaping die is the same as that of the original convex hull.
As shown in fig. 3, the dashed line of reference numeral 30 represents the outline of the convex hull design, and reference numeral 20 represents the existing hemispherical first pass structure; the thick solid line in the figure represents the structure of the first pass of the present invention, which includes a valley 11 (first arc), a peak 12 (second arc), a slope 13 (third arc) and a transition fillet 14, which are sequentially connected to the module backplane 40; reference numeral 50 denotes a central axis of the surface of revolution.
Under the prerequisite of the outer material of control convex closure inflow like this, through the material fully warp in the convex closure, realized the high formability of convex closure when guaranteeing not to deteriorate module backplate dimensional accuracy, enlarged module backplate stamping forming processing to the adaptation window of raw and other materials.
The following will further describe the two-pass forming method of the convex hull of the module back plate according to the present invention with reference to the following embodiments and the accompanying drawings.
Referring to fig. 4, in this embodiment, in order to ensure sufficient structural strength and rigidity of a certain module backboard, a material with a raw material thickness t of 0.8mm and a yield strength of 200MPa is used for punching. The back plate is typically convex hull design, the height H is 12mm, the inclination angle a is 50 °, the radius Ru of the upper table top is 2.93mm, the radius Rb of the lower table top is 13mm, and the radius Rb1 of the lower table top including the transition arc is 16.04 mm; the radius of the upper transition fillet and the lower transition fillet is r 1-2 mm, and r 2-4 mm. The corresponding content of the figure sizes in the drawings can refer to the corresponding labels in fig. 1.
Because the traditional first-pass hemispherical profile preforming and second-pass shaping are adopted, severe cracking occurs. The rotating curved surface of the 'peak-valley-peak' shape of the invention is used as the profile of the first-pass preforming mold, wherein the preforming radius increment is the same as that of the hemispherical profile, the Δ R is 1.89mm, the radius Rb2 of the bottom forming area is 17.93mm, the heights of the peaks of the valleys are respectively h 1mm 6mm, h 2mm 9mm, the radiuses of four sections of circular arcs are respectively R5 mm 5.54mm, R6 mm 3mm, R7 mm 35.41mm, R8 mm 3mm, the second-pass forming processing adopts the original convex hull design profile for shaping, and the final convex hull is formed well without cracking. Therefore, on the premise of ensuring that the dimensional accuracy of the module backboard is not degraded, the convex hull is formed twice under the high-strength material.
Claims (5)
1. A two-pass forming processing method for a module backboard convex hull comprises a first pass of pre-forming and a second pass of shaping into a designed shape, wherein the second pass of shaping processing is carried out after the first pass of pre-forming, and the design of the molded surface of a shaping die is the same as that of an original convex hull; the method is characterized in that the first pre-forming step adopts the following forming method:
taking the design center of an original convex hull as a central axis, and stamping and forming a rotary curved surface according to a 'peak-valley-peak' shape with a 'valley' shape in the middle and two peak-peak shapes on two sides;
the rotating curved surface comprises a valley-shaped first section of circular arc, a peak-shaped second section of circular arc, a slope-shaped third section of circular arc and a fourth section of circular arc, wherein the valley-shaped first section of circular arc is symmetrical relative to the center axis, and the peak-shaped second section of circular arc, the slope-shaped third section of circular arc and the fourth section of circular arc are sequentially outward;
and the number of the first and second electrodes,
(1) the arc bottom of the first arc is positioned on the central axis, the height H1 between the arc bottom and the plane where the surface of the back plate is positioned is 1/2H, and H is the design height of the convex hull; the height H2 between the arc top of the second section of arc and the plane where the surface of the back plate is located is 3/4H, the distance Rc between the arc top of the second section of arc and the center line is 1/2Rb, and the Rb is the design radius of the lower table surface of the convex hull without the arc chamfer;
(2) the radius r6 of the second section of circular arc is 1/4H, and the radius r5 of the first section of circular arc is Rb 2/(8r6) -r 6/2;
(3) taking the distance from the central axis at the joint of the fourth circular arc and the surface of the connecting back plate as the radius Rb2 of the bottom forming zone, the radius Rb2 satisfies the following conditions: rb2 ═ Rb1+ Δ R, where Δ R is the preform radius increment and Rb1 is the convex hull lower plateau design radius including the rounded chamfer.
2. The method of claim 1, wherein the fourth arc is a rounded transition corner.
3. The two-pass forming method for the convex hull of the module back plate according to claim 1 or 2, wherein the radius r8 of the fourth segment of the circular arc is 3-4 mm.
4. The method of claim 1, wherein the radius r7 of the third arc is set according to the existing constraints.
5. The two-pass forming method for the convex hull of the module backboard according to claim 1, wherein Δ R is 1-3 mm.
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| CN202010901629.9A CN114101474A (en) | 2020-08-31 | 2020-08-31 | Two-pass forming processing method for convex hull of module backboard |
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| CN202010901629.9A CN114101474A (en) | 2020-08-31 | 2020-08-31 | Two-pass forming processing method for convex hull of module backboard |
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