The present invention relates to a cutting device and a cutting method. Priority is claimed on Japanese Patent Application No. 2015-020331, filed on Feb. 4, 2015, the content of which is incorporated herein by reference.
For example, a thin-plate processed part 8 (a press-formed product) shown in
Here, in the cutting step shown in
However, from the viewpoint of manufacturing accuracy or the like of a die and punch, it is not easy to control the clearance CL/t between the upper blade 12 and the lower blade 11 to a predetermined value (less than or equal to 10%, for example) when cutting the plate material 1 along the curved cutting line 2. Further, even in a case where the plate material 1 is cut in a linear fashion, the clearance CL/t varies due to elastic deformation or the like of a die and punch, which occurs at the time of the cutting of the plate material 1. Therefore, it is not easy to control the clearance CL/t to a predetermined value and to suppress burr occurrence in a mass production process.
Here, Patent Document 1 discloses a punching die in which burrs generated during punching are crushed by rollers provided up and down. Further, Patent Document 2 discloses a method of preventing the generation of burrs in the cross section of a hole-formed portion by performing punch pressing at the same position and in the same shape from above and below a plate material.
However, in Patent Document 1, the burrs generated by the punching are crushed, and therefore, the crushed portion is hardened, so that the workability is further lowered. Further, in Patent Document 2, since punch pressing at the same position and in the same shape is performed from above and below the plate material, two press machines are required, and thus a cost such as the cost of equipment increases.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. H10-263721
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. H11-221628
The inventors of the present invention have focused on falling-down of the plate material 1 when cutting the plate material 1, as a factor of occurrence of the burrs in the processed material 6.
If such falling-down of the plate material 1 occurs, it is difficult for the lower blade 11 to bite into the plate material 1, and thus cracking from a place which is in contact with the lower blade 11 becomes difficult to occur. Further, due to the falling-down of the plate material 1, tension acts on the plate material 1, and thus cracking from the upper blade 12 becomes easy to occur. For this reason, if the upper blade 12 is further moved down from the state shown in
The present invention has been made in view of the above circumstances and has an object to provide a cutting device and a cutting method, in which occurrence of burrs when cutting off an end portion of a plate material can be easily suppressed at low cost.
In order to solve the above problem, the present invention adopts the following.
(1) According to an aspect of the present invention, there is provided a cutting device for obtaining a processed material by cutting off an end portion of a plate material by a first cutting blade and a second cutting blade which relatively approach each other, the cutting device including: a first contact part and the first cutting blade which clamp a processed material portion to be the processed material, of the plate material, from front and back surfaces thereof; the second cutting blade and a second contact part which clamp an end material portion to be the end portion, of the plate material, from front and back surfaces thereof; and a drive part which causes the first cutting blade and the second cutting blade to start relative approach each other while maintaining a flat state where the processed material portion and the end material portion are on the same plane, on at least one of the front surface and the back surface of the plate material.
(2) In the aspect according to the above (1), a curved portion is formed in each of the first cutting blade and the second cutting blade in a case of being viewed in a direction in which the first cutting blade and the second cutting blade approach each other.
(3) In the aspect according to the above (2), the curvature of the curved portion of the first cutting blade may be greater than or equal to −0.07 mm −1 and less than or equal to 0.20 mm −1.
(4) In the aspect according to any one of the above (1) to (3), a clearance between the first cutting blade and the second cutting blade may be more than 10% and less than or equal to 30%.
(5) In the aspect according to any one of the above (1) to (4), a pressurizing force of the second contact part with respect to the end material portion may be greater than or equal to 0.05 kN.
(6) In the aspect according to any one of the above (1) to (5), the second contact part may include a flat portion which comes into contact with the end material portion of the plate material.
(7) In the aspect according to the above (6), a minimum width dimension of the flat portion may be greater than or equal to a plate thickness of the plate material.
(8) In the aspect according to the above (6) or (7), a maximum width dimension of the flat portion may be less than 0.5 times a minimum width dimension of the end portion of the plate material.
(9) In the aspect according to the above (6) or (7), a maximum width dimension of the flat portion may be less than or equal to 30 mm.
(10) In the aspect according to any one of the above (1) to (9), the cutting device may further include: an end member removal part which applies an external force to the end portion after cutting of the plate material and after release of clamping of the end portion by the second cutting blade and the second contact part.
(11) According to another aspect of the present invention, there is provided a cutting method for obtaining a processed material by cutting off an end portion of a plate material by a first cutting blade and a second cutting blade which relatively approach each other, the cutting method including: clamping a processed material portion to be the processed material, of the plate material, from front and back surfaces thereof; clamping an end material portion to be the end portion, of the plate material, from front and back surfaces thereof; and causing the first cutting blade and the second cutting blade to start relative approach each other while maintaining a flat state where the processed material portion and the end material portion are on the same plane, on at least one of the front surface and the back surface of the plate material.
(12) In the aspect according to the above (11), tension may not be applied to either of the front surface or the back surface of the plate material at the time of start of the approach.
(13) In the aspect according to the above (11) or (12), a clearance between the first cutting blade and the second cutting blade may be set to be more than 10% and less than or equal to 30%.
(14) In the aspect according to any one of the above (11) to (13), a pressurizing force when clamping the end material portion may be set to be greater than or equal to 0.05 kN.
(15) In the aspect according to any one of the above (11) to (14), the plate material may be a steel plate having tensile strength greater than or equal to 440 MPa.
(16) In the aspect according to any one of the above (11) to (15), a plate thickness of the plate material may be in a range of 0.6 mm to 3.6 mm.
According to each of the above aspects of the present invention, the occurrence of burrs when cutting off the end portion of the plate material can be easily suppressed at low cost.
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, and thus an overlapping description thereof is omitted.
A material of the plate material 1 is, for example, metal such as iron, aluminum, stainless steel, copper, titanium, magnesium, or steel. The material of the plate material 1 is not limited to only those listed above and may be a composite material composed of metal and resin, a dissimilar metal, or the like.
Further, a plate thickness of the plate material 1 is preferably in a range of 0.6 mm to 3.6 mm, more preferably in a range of 0.6 mm to 2.3 mm, and further preferably in a range of 0.6 mm to 1.8 mm.
As shown in
The lower blade 101 is fixed to a floor surface (not shown). The plate holder 104 is made to be movable in the vertical direction Z. Then, when cutting the plate material 1, a processed material portion 4 of the plate material 1 is clamped by the lower blade 101 and the plate holder 104 from two surfaces (the front and back surfaces) in a through-thickness direction of the plate material 1.
The upper blade 102 is disposed to be separated from the lower blade 101 by a predetermined distance such that a clearance CL/t (a value obtained by dividing a distance CL between the upper blade 102 and the lower blade 101 by a plate thickness t of the plate material 1: refer to
Further, as shown in
The falling-down prevention member 105 has a trapezoidal cross section, as shown in
Further, the falling-down prevention member 105 is disposed such that a distance D between the side end surface 105c thereof and the end surface 101a of the lower blade 101 is in a range of 0.01 mm to 100 mm. The distance D is more preferably in a range of 0.01 mm to 50 mm and further preferably in a range of 0.01 mm to 10 mm.
When cutting the plate material 1, the end portion 3 in the longitudinal direction of the plate material 1 is clamped by the upper blade 102 and the falling-down prevention member 105 from two surfaces (the front and back surfaces) in the through-thickness direction of the plate material 1. At this time, the elastic body 107 is set so as to have a pressurizing force greater than or equal to 0.05 kN.
The pair of scrap boxes 110 is disposed below the falling-down prevention members 105, as shown in
Further, as shown in
A width W of the top plate surface 105a of the falling-down prevention member 105 (the length of the top plate surface 105a in a direction crossing the cutting line 2 of the plate material 1: refer to
On the other hand, it is preferable that the minimum dimension of the width W of the top plate surface 105a is greater than or equal to the plate thickness of the plate material 1. In this case, it is possible to increase the thickness of the falling-down prevention member 105, and thus it is possible to improve the strength of the falling-down prevention member 105.
Next, a method of obtaining a processed material 7 by cutting off the end portion 3 of the plate material 1 by using the cutting device 100 will be described. First, as shown in
Subsequently, the upper blade 102 is moved down (the upper blade 102 is brought close to the lower blade 101), and thus the end portion 3 of the plate material 1 is cut. At this time, since the falling-down prevention member 105 is pressing the end portion 3 of the plate material 1, the falling-down (refer to
Finally, as shown in
Through the above steps, it is possible to obtain the processed material 7 from the plate material 1 by using the cutting device 100. Then, stretch flanging is performed on the processed material 7 by using a press forming device 20 shown in
According to the cutting device 100 according to the embodiment described above, the upper blade 102 starts to approach the lower blade 101 while the lower surface of the end portion 3 of the plate material 1 is pressurized by the falling-down prevention member 105. In other words, the upper blade 102 starts to approach the lower blade 101 while maintaining a flat state where the processed material portion 4 and the end portion 3 of the plate material 1 are on the same plane (without applying tension to two surfaces in the through-thickness direction of the plate material 1). For this reason, it is possible to prevent the end portion 3 of the plate material 1 from falling-down, and thus it is possible to suppress the occurrence of burrs in the processed material 7. Therefore, the occurrence of burrs can be easily suppressed at a low cost.
As described above, in the cutting device 10 of the related art (refer to
Further, the higher the tensile strength of the plate material 1 is, the more easily the falling-down occurs. Therefore, from the viewpoint of the effect of falling-down prevention, the plate material 1 is preferably a steel plate having tensile strength greater than or equal to 440 MPa, more preferably a steel plate having tensile strength greater than or equal to 590 MPa, and further preferably a steel plate having tensile strength greater than or equal to 980 MPa.
Further, the thinner the plate thickness of the plate material 1 is, the more easily the falling-down occurs. Therefore, the thinner the plate thickness of the plate material 1 is, the greater the effect of falling-down prevention becomes.
Further, in the plate material 1, in a case where the curvature of the cutting line 2 of the plate material 1 is greater than or equal to −0.07 mm −1, the falling-down at the time of cutting occurs conspicuously. For this reason, in a case where the curvature of the cutting line 2 is greater than or equal to −0.07 mm −1, the effect of falling-down prevention increases. Here, the negative curvature represents a concave curve, and the positive curvature represents a convex curve.
On the other hand, in a case where the curvature of the cutting line 2 of the plate material 1 exceeds 0.20 mm −1, when the stretch flanging is performed on the processed material 7 by using the press forming device 20 shown in
Therefore, it is preferable that the curvature of the cutting line 2 of the plate material 1 is greater than or equal to −0.07 mm −1 and less than or equal to 0.20 mm−1.
In other words, since the plate material 1 is cut along the shapes of the lower blade 101 and the upper blade 102, it is preferable that the curvature of the end surface 101a of the lower blade 101 is greater than or equal to −0.07 mm −1 and less than or equal to 0.20 mm−1 and it is preferable that the curvature of the end surface 102a of the upper blade 102 is greater than or equal to −0.20 mm−1 and less than or equal to 0.07 mm−1.
Next, examples performed in order to confirm the operation and effects of the present invention will be described.
A processed material was manufactured by cutting off the end portion 3 of the plate material 1 by using the cutting device 100 according to the embodiment. At this time, the curvature (a reciprocal of a radius of curvature) of the cutting line 2 of the plate material 1 was set to five levels of Conditions 1 to 5 in Table 1 below (Condition 3 shows a case where the cutting line 2 is linear). In Conditions 1 to 3 and 5 in Table 1, the width W of the top plate surface 105a of the falling-down prevention member 105 was set to 3 mm and the clearance CL/t was set to 25%. On the other hand, in Condition 4 in Table 1, the width W of the top plate surface 105a was set to 3 mm and the clearance CL/t was set to two levels of 10% and 25%. As the plate material 1, a steel plate having tensile strength of 980 MPa and a plate thickness of 1.4 mm was used. The set load (a pressurizing force to the plate material 1) of the falling-down prevention member 105 was set to 5.0 kN.
Further, for comparison, a processed material was likewise manufactured using the cutting device 10 of the related art shown in
Then, with respect to these processed materials, the cross section perpendicular to the width direction was photographed and the burr height was measured. The results are shown in
As shown in
Further, also from the results shown in
Similar to the case of Example 1, a processed material was manufactured with the curvature of the cutting line 2 of the plate material 1 set to that in Condition 4 in Table 1. The clearance CL/t was set to 25%, and the set load of the falling-down prevention member 105 was set to four levels of 0.05 kN, 1.5 kN, 3.0 kN, and 5.0 kN. Then, the stretch flanging was performed on these processed materials, and the relative value (limit H/limit H_reference) of a limit flange height was determined. The results are shown in
The relative value (limit H/limit_reference) of the limit flange height is a value obtained by dividing the limit flange height (limit H) in which a flange height is increased at a pitch of about 1 mm and cracking of an edge portion or local necking in the through-thickness direction does not occur, by the limit flange height (limit H_reference) of a processed material obtained under the condition of clearance CL/t=10% by using the cutting device 10 of the related art.
Here, the “flange height” is the flange height of the portion excluding a rising curvature portion at a root of a formed flange. Therefore, in a case where a flange having the same height as the processed material obtained under the condition of clearance CL/t=10% can be formed, the relative value (limit H/limit H_reference) of the limit flange height is 1.0, and in a case where only a flange height to the extent that it does not come out from the rising curvature portion can be formed, the relative value of the limit flange height is zero.
A large burr was generated in the processed material manufactured by the cutting device 10 of the related art. For this reason, as shown in
On the other hand, in a case where the set load of the falling-down prevention member was set to be greater than or equal to 0.05 kN, the relative value of the limit flange height was more than 0.9 without occurrence of a large burr. From this result, it could be confirmed that in the cutting device 100, a processed material having good stretch flangeability could be manufactured even in a case where the clearance CL/t is as large as 25%.
Similar to the case of Example 2, a processed material was manufactured with the curvature of the cutting line 2 of the plate material 1 set to that in Condition 4 in Table 1. The set load of the falling-down prevention member 105 was set to 5.0 kN and the width W of the top plate surface 105a of the falling-down prevention member 105 was set to three levels of 3 mm, 6 mm, and 10 mm. Then, similar to the case of Example 2, the relative value (limit H/limit reference) of the limit flange height was determined. The results are shown in
As shown in
On the other hand, in the processed material manufactured by the cutting device 100 according to the embodiment, the relative value (limit H/limit reference) of the limit flange height was about 1.0 without occurrence of a large burr. Also from this result, it could be confirmed that in the cutting device 100, a processed material having good stretch flangeability could be manufactured even in a case where the clearance CL/t is as large as 25%.
The embodiment of the present invention has been described above. However, the above-described embodiment has been presented as an example, and the scope of the present invention is not limited to only the above-described embodiment. The above-described embodiment can be implemented in various other modes, and various omissions, substitutions, and changes can be made within a scope which does not depart from the gist of the invention. The above-described embodiment and modifications thereof are included in the scope of the invention described in the claims and the equivalents thereof as well as in the scope or the gist of the invention.
For example, in the above-described embodiment, a case where the end portion 3 in the longitudinal direction of the plate material 1 is cut off is shown. However, the cutting device 100 may be configured so as to cut off an end portion in the width direction of the plate material 1. Further, the cutting device 100 may be configured so as to cut off an end portion in a circumferential direction of the plate material 1 (such that the cutting line 2 of the plate material 1 becomes one closed line).
Further, for example, in the above-described embodiment, a case where the upper blade 102 has the pressing bar 109 and the elastic body 108 is shown. However, the pressing bar 109 and the elastic body 108 may be provided in the falling-down prevention member 105. Further, instead of the pressing bar 109 and the elastic body 108, a gas blowing device for blowing gas to the end portion of the plate material may be provided.
Further, for example, in the above-described embodiment, a case where the cutting device 100 is provided with a pair of upper blades 102 is shown. However, the cutting device 100 may be provided with a single upper blade 102.
Further, for example, in the above-described embodiment, a case where the plate material 1 is cut in a curved line shape is shown. However, the plate material 1 may be cut in a linear fashion.
Further, for example, in the above-described embodiment, a case where the falling-down prevention member 105 has the inclined surface 105b is shown. However, the inclined surface 105b may be a vertical surface. However, from the viewpoint of securing a space for disposing the elastic body 107, the viewpoint of improving the strength of the falling-down prevention member 105, and the like, it is preferable that the inclined surface 105b is provided.
According to the present invention, it is possible to provide a cutting device and a cutting method, in which occurrence of burrs when cutting off an end portion of a plate material can be easily suppressed at low cost.
1: plate material
2: cutting line
3: end portion of plate material
7: processed material
20: press forming device
100: cutting device
101: lower blade (first cutting blade)
102: upper blade (second cutting blade)
104: plate holder (first contact part)
105: falling-down prevention member (second contact part)
107: elastic body
110: scrap box
120: drive unit (drive part)
Number | Date | Country | Kind |
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2015-020331 | Feb 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/052888 | 2/1/2016 | WO | 00 |