Patent Application
20110094085
The present invention relates to a method for producing a contour strip where thick and thin portions are formed to be lined up in a width direction.
As is well known, a contour strip made of metal is used for a lead frame of, for example, a LED, a power transistor, or the like.
As techniques for producing the contour strip, there are a molding technique using a plate die and a roller and a molding technique using a grooved roller and a flat roller as described in PTL 1 and 2.
In a technique disclosed in PTL 1, there is provided a pressing roller that faces the surface of a plate die. The pressing roller rolls and presses a long plate material, which is provided on the surface of the plate die, within a range corresponding to the surface of the plate die. By moving the plate material to the rear side from the front end of the die by a predetermined length, the pressing roller produces a contour strip each time the pressing and rolling movement is completed.
Further, in a technique disclosed in PTL 2, a flat roller having a constant roller radius and a grooved roller, which includes a plurality of roller portions of which roller radii vary in the direction of an axis, are disposed parallel to an axis so as to be close to each other; roll a plate material inserted into a gap formed between the flat roller and the grooved roller; and form thin portions at the plate material in the longitudinal direction by the respective roller. Accordingly, a contour strip is produced.
Since the thickness of each of these contour strips varies in the width direction, distortion is generated, so that the contour strips are apt to be deformed. For this reason, as described in PTL 3 to 5, annealing or stretching is performed on the molding material having a deformed cross-section to improve a dimensional accuracy.
In a technique disclosed in PTL 3, a first rolling mill, which pulls and shapes a formed long metal plate, is provided on the rear side of a die device, which includes a plate die and a pressing roller, with an intermittent feeding and absorbing device interposed therebetween. A degreasing device and a continuous annealing furnace are provided on the rear side of the first rolling mill. A second rolling mill and a slit cutter disposed close to the second rolling mill are provided on the rear side of the degreasing device and the continuous annealing furnace. While a long metal plate molded by the die device is being moved at a constant speed as it is by the intermittent movement of a metal material, shaping, annealing, and width working are continuously performed.
In a technique disclosed in PTL 4, a metal plate having a deformed cross-section is clamped by clamps and distortion is stretched by the pulling of the metal plate in the longitudinal direction. The clamp is formed of a plurality of divided plates that is divided in a direction crossing the pulling direction of the metal plate, and a clamping force is controlled according to the material and shape of the metal plate.
A technique disclosed in PTL 5 is a method for stretching a contour strip including clamping a contour strip at different positions in the longitudinal direction by clamping tools, and applying a tensile force to the contour strip by moving the clamping tools so that a gap between the clamping tools is increased. The clamping tools are rotated according to the deformation of the contour strip that is caused by pulling.
However, since a strip has a deformed cross-section, it may not be possible to avoid the generation of distortion during molding and there is a demand for a technique that further improves the accuracy regarding the shape and dimensions.
The invention has been made in consideration of the above-mentioned circumstances, and an object of the invention is to provide a method for producing a contour strip of which accuracy can be further improved.
According to an embodiment of the invention, there is provided a method for producing a contour strip. The method includes a rough rolling step for rolling a plate material to form a contour molding material where thick and thin portions are lined up in a width direction, a slitting step for slitting the contour molding material in a longitudinal direction at the middle position in the width direction of the thick portion or the thin portion disposed at the both side edge portions thereof and slitting off the both side edge portions to form a contour slit material, and a stretching step for stretching the contour slit material to obtain a contour strip. Rolling is carried out in the rough rolling step so that Δt is 0.01 or less, e is 0.15 or less, D1 is 0.4 or less, and a rough rolling management value X determined by Δt×e×D1 is 5×10−4 or less, assuming that the deviation of plate-thickness at the thin portion from a target value is Δt (mm), an actual measurement of the radius of curvature at a corner formed by the side surface and the top surface of the tick portion is e (mm), and an actual measurement of curvature per meter-length of the contour molding material is D1 (mm). The contour molding material is slit in the slitting step so that |A−B| is 0.08 or less assuming that an actual measurement of the difference in the width from the side edge of the thick portion or the thin portion disposed at the both side edge portions is |A−B| (mm). The deformed cross-section slit material is stretched in the stretching step so that D2 is 0.13 or less assuming that an actual measurement of curvature per meter-length of the contour strip is D2 (mm).
Further, in the method according to the embodiment of the invention, the contour strip may be produced so that the product (X×Y×Z) of a rough rolling management value X, a slitting management value Y, and a stretching-management value Z is 6×10−6 or less assuming that |A−B| measured in the slitting step is the slitting management value Y and D2 measured in the stretching step is the stretching-management value Z.
Furthermore, in the method according to the embodiment of the invention, in the rough rolling step, the plate material may be intermittently fed in the longitudinal direction by a die that includes a molding surface for forming the thick and thin portions and a rolling roller that is reciprocated in the longitudinal direction of the molding surface of the die between a position facing the molding surface of the die and a position deviated from the molding surface of the die, when the rolling roller is positioned at the position deviated from the molding surface of the die, and the plate material may be interposed between the rolling roller and the molding surface of the die and may be rolled when the rolling roller is positioned at a position facing the molding surface of the die.
Furthermore, in the method according to the embodiment of the invention, in the rough rolling step, brake members, which come into contact with the plate material at the upstream position of the die, may be pressed and apply a braking friction force to the plate material while the contour molding material is wound at a constant speed at the downstream position of the die by a winding mechanism, and the contour molding material may be pulled while being bent by pressing an oscillation roller, which comes into contact with the other surface of the contour molding material by a spring while one surface of the contour molding material is supported by support rollers between the die and the winding mechanism.
In this case, assuming that the natural frequency of the oscillation roller, which is pressed by the spring, is f1 and the frequency of the rolling roller is f2, a spring constant of the spring may be determined so that f1 exceeds f2 and is equal to or smaller than two times of f2.
Moreover, in the method according to the embodiment of the invention, in the rough rolling step, the plate material may be interposed and rolled between a grooved roller on which small-diameter roller portions for forming the thick portions and large-diameter roller portions for forming the thin portions are formed to be lined up in the direction of an axis, and a flat roller that has a constant radius in the direction of an axis.
In this case, the grooved roller may be formed so that wide large-diameter roller portions and narrow large-diameter roller portions narrower than the wide large-diameter roller portions are formed to be lined up with small-diameter roller portions interposed therebetween, the diameter of the wide large-diameter roller portion is larger than that of the narrow large-diameter roller portion, and Δr/h is in the range of 0.01 to 0.5 assuming that a difference between the radii of both the large-diameter roller portions is Δr and a difference between the radii of the narrow large-diameter roller portion and the small-diameter roller portion is h.
Further, in the method according to the embodiment of the invention, in the slitting step, tension may be controlled by pressing the respective contour slit materials between the winding mechanism and the slitter while the respective contour slit materials separated by the slitter are wound at a constant speed by the winding mechanism.
Furthermore, in the method according to the embodiment of the invention, in the stretching step, the stretched contour strip may be wound at a constant speed by a winding mechanism while the contour slit material is fed at a constant speed by a feed mechanism. In addition, while slack portions are formed at the contour slit material and the contour strip between the feed mechanism and the winding mechanism, the contour slit material may be clamped by elastic members between both slack portions so that tension is applied to the contour slit material.
According to the method of the invention, it may be possible to produce a contour strip that includes thick portions and thin portions and has accurate dimensions and an accurate shape.
An embodiment in which a method for producing a contour strip according to the invention is applied to the production of a contour strip made of a copper alloy will be described below.
A method for producing the contour strip E according to a first embodiment includes a rough rolling step for rolling a plate material M to form a contour molding material C where thick and thin portions y and m are lined up in a width direction; an annealing step for annealing the contour molding material C; a finishing rolling step for carrying out finishing rolling on the annealed contour molding material C; a slitting step for slitting the thin portions m of the contour molding material C, which has been subjected to the finishing rolling, in a longitudinal direction by a slitter to separate a contour slit material E where thin portions m are formed on both sides of a thick portion y; and a stretching step for stretching the warpage of the contour slit material E to obtain a target contour strip G.
The plate material M is obtained by forming a ductile material in the shape of a plate, and is made of a copper alloy of, for example, Cu-0.1% Fe-0.03% P.
Meanwhile, the plate material is worked in the respective steps, so that the shapes, dimensions, and the like of the thick and thin portions are changed. However, in this specification, for convenience of description, the thick and thin portions are denoted by the same reference characters, that is, the thick portion is denoted by y and the thin portion is denoted by m in the respective steps.
The respective steps of the method for producing the contour strip will be described in detail below.
A rough rolling device 51 is provided in the rough rolling step. The rough rolling device 51 rolls the plate material M wound in the shape of a coil while feeding the plate material, and winds the contour molding material C, which is formed by the rolling, in the shape of a coil.
As shown in
As shown in
As shown in
Meanwhile, the axis of the rolling roller 59 is directed to the direction orthogonal to the feeding direction of the plate material M. As shown by arrows of
Further, when the rolling roller 59 is disposed at the upstream position of the die 58, the plate material M is fed between the molding surface 57 of the die 58 and the rolling roller 59. Then, the rolling roller 59 is moved along the molding surface 57 of the die 58 toward the downstream side, so that the plate material M is pressed against and made to bite into the molding surface 57 of the die 58. Accordingly, one surface of the plate material M is molded so as to correspond to the molding surface 57. Further, if being moved to the position of the downstream end of the die 58, the rolling roller 59 is moved again to the upstream position that is deviated from the molding surface 57 of the die 58. When the rolling roller 59 is disposed at the upstream position deviated from the molding surface 57 of the die 58, the plate material M is fed only by a predetermined pitch by the speed adjusting mechanism 56 as described below. Furthermore, the same operation is repeated and the rolling roller 59 is reciprocated, so that the plate material M is molded by the molding surface 57 of the die 58.
If the rolling roller 59 is reciprocated along the molding surface 57 of the die 58 while the plate material M is intermittently fed by a predetermined pitch in this way, there is obtained a contour molding material C where the thick portion y formed by the groove portion 61 of the die 58 and the thin portions m formed by the protruding portions 62 are continuously formed on the plate material M. As shown in
The material pressing mechanism 55 clamps the plate material M at the upstream position of the rolling mill 53 as shown in
The speed adjusting mechanism 56 adjusts a difference in speed between the intermittent feeding and the winding of the recoiler 54 at a constant speed by pulling and intermittently feeding the contour molding material C that is rolled by the rolling mill 53, and bending the middle portion of the contour molding material. Specifically, the speed adjusting mechanism includes a pair of support rollers 66 that is disposed with a gap therebetween in the feeding direction of the contour molding material C and comes into contact with the lower surface of contour molding material C, an oscillation roller 67 that comes into contact with the upper surface of the contour molding material C between the support rollers 66, and a spring 68 that pushes the oscillation roller 67 down from above. Further, when the oscillation roller 67 pushes the contour molding material C down from above, the contour molding material C is bent between the support rollers 66. When the rolling mill 53 carries out rolling (when the contour molding material C is stopped at the rolling mill 53), the bent portion of the contour molding material C between the support rollers 66 is pulled by the winding force of the recoiler 54. Accordingly, the oscillation roller 67 is moved up so as to reduce the length of the bent portion. Therefore, when the rolling roller 59 is disposed at an upstream position deviated from the molding surface 57 of the die 58, the contour molding material C (the plate material M) is intermittently fed only by a predetermined pitch from the rolling mill 53 until the oscillation roller 67 is pushed down by the pressing force of the spring 68 so as to increase the length of the bent portion of the contour molding material C between the support rollers 66 and the rolling roller 59 is moved to make the plate material M bite into the molding surface 57 of the die 58.
Meanwhile, in the example shown in
In the speed adjusting mechanism 56, the spring 68 applies predetermined tension to the contour molding material C by pressing the oscillation roller 67. However, this tension is set to be smaller than the tension caused by the winding of the recoiler 54 so as not to obstruct the winding of the recoiler 54 at a constant speed. Meanwhile, the push-down force of the spring 68 allows a pulling force, which intermittently feeds the contour molding material C, to be applied to the contour molding material against the braking friction force of the material pressing mechanism 55.
In this case, the intermittent feeding of the contour molding material C, which is carried out by the speed adjusting mechanism 56, has been synchronized with the reciprocation of the rolling roller 59 of the rolling mill 53. However, it is preferable that the variation of tension, which is applied to the contour molding material C by the oscillation roller 67, be small in terms of the excellent accuracy of molding. For this reason, the spring constant of the spring 68 pressing the oscillation roller 67 is set to be large, and the natural frequency of the oscillation roller 67 is set to be increased with respect to the frequency of the rolling roller 59. Specifically, assuming that the natural frequency of the oscillation roller 67 is f1 and the frequency of the rolling roller 59 is f2, f1 is set to exceed f2 and be equal to or smaller than two times of f2.
If the natural frequency f1 of the oscillation roller 67 corresponds to the frequency f2 of the rolling roller 59 (f1=f2), resonance occurs as shown by a broken line of
For example, if the reciprocating frequency f2 of the rolling roller 59 is set to 300 times per minute, the natural frequency f1 of the oscillation roller 67 is set to be equal to the reciprocating frequency f2 of the rolling roller 59 (300 per minute=5 per second), and the weight of the oscillation roller 67 is 10 kg, the spring constant is about 1.0. However, if the natural frequency f1 of the oscillation roller 67 is set to 1.5 times the reciprocating frequency f2 of the rolling roller 59, the spring constant is about 2.4. If the spring constant of the spring 68 connected to the oscillation roller 67 is set to be larger than a value calculated from the frequency f2 of the rolling roller 59 as described above, the thick portion y and the thin portions m can be molded with highly accurate dimensions and a highly accurate shape.
Further, assuming that the deviation of plate thickness at the thin portion m of the contour molding material C from a target value t is Δt (mm), an actual measurement of the radius of curvature at a corner formed by the side surface and the top surface of the thick portion y is e (mm), and an actual measurement of curvature (the degree of meandering) per meter-length of the contour molding material C is D1 (mm) (see
Here, the curvature is the maximum displacement between a straight line and the side edge when two points, which are apart from each other by 1 meter along the side edge that forms the inside of a bend, are connected to each other by the straight line as shown in
It may be possible to obtain a contour molding material C having a high accuracy by managing the rough rolling management value X, which is defined by the product of Δt, e, and D1, at a more accurate value while managing the deviation Δt of plate thickness at the thin portions m, the radius e of curvature at a corner, and the curvature D1, respectively. In addition, since the curvature D affects the width dimension (|A−B|) of the thin portion in the following slitting step, it may be possible to improve the slitting accuracy in the following step by managing the curvature in the rough rolling step.
In the annealing step, oil is removed from the contour molding material C by heating the contour molding material C so that oil adhering to the contour molding material C is vaporized. Then, the contour molding material C is heated up to 600° C. in, for example, a nitrogen gas atmosphere, and is cooled.
In the finishing rolling step, while the contour molding material C, which is molded by the rough rolling step, is fed at a constant speed, the corrugated surface formed on the surface of the contour molding material C is gradually pressed and formed by a roller (not shown) that is formed in the shape of the surface of the thick and thin portions y and m.
As shown in
The tension control mechanism 74 adjusts the tension between the contour slit material E and the recoiler 73 by pressing rollers 75, which come into contact with both surfaces of the contour slit material E, by fluid pressure such as air pressure, or the like. Reference numeral 76 of
Both side portions, which are shown in
The slitting step is not a final step, and the final contour strip G is obtained through the next stretching step. However, it may be possible to improve the accuracy of the shape and dimensions of the final contour strip G by managing the width dimension |A−B| in the slitting step.
As shown in
The stretching mechanism 82 clamps the contour slit material E by clamp members 84 at two positions with a gap therebetween in a longitudinal direction, and applies predetermined tension to the contour slit material E by moving the clamp members 84 so that the clamp members become distant from each other in the longitudinal direction of the contour slit material E. Accordingly, the final contour strip G is formed. As shown in
Meanwhile, the slack portions Es and Gs have been formed on both sides of the stretching mechanism 82 in the example shown in
Assuming that an actual measurement of curvature (the degree of meandering) per meter-length of the contour strip G measured by the same measuring method as the method for measuring D1 shown in
Further, assuming that |A−B| measured in the slitting step is a slitting management value Y and D2 measured in the stretching step is a stretching-management value Z, as the determination of whether the final contour strip G is an acceptable strip or a rejected strip, the final contour strip is determined as an acceptable strip if the product (X×Y×Z) of the rough rolling management value X, the slitting management value Y, and the stretching-management value Z is 6×10−6 or less. The final contour strip is determined as a rejected strip if the product is outside this range.
An intended contour strip G is obtained through the above-mentioned respective steps. Further, in the rough rolling step, the dimensions Δt, e, and D1 of the respective portions of the contour molding material C are managed, respectively, and the rough rolling management value X, which is obtained by the combination of the dimensions, is managed so as to be in a predetermined range. While the difference |A−B| between the width dimensions of the thin portions m is managed in the slitting step and the curvature D2 of the contour strip G is managed in the stretching step, the product (X×Y×Z) of the rough rolling management value X, the slitting management value Y, and the stretching-management value Z is finally managed and whether the final contour strip is an acceptable strip or a rejected strip is determined in this production process.
It may be possible to obtain a contour strip G having a high accuracy by setting and managing items to be managed, which are obtained by the combination of these measurements, in addition to managing the respective measurements, as described above. That is, if the management value obtained by the combination of these measurements is deviated from a desired management range even though each of the measurements is in the management range thereof, a contour strip is determined as a rejected strip. Conversely, it may be possible to obtain a contour strip having a high accuracy on the whole while easily managing the respective items by setting the management range to a slightly large range based on the idea that the close management using the management value obtained by the combination makes it possible to compensate the accuracy of each of the measurements by the accuracy of the other items to be managed. Further, it may be possible to efficiently manage the items.
Moreover, in that case, it may be possible to finish an end product with a very high accuracy by managing the curvature, which affects the width dimension of the thin portion m of the final contour strip G, in both the rough rolling step and the stretching step.
Next, a second embodiment of the invention will be described with reference to
Like the first embodiment, the second embodiment also includes a rough rolling step, an annealing step, a finishing rolling step, a slitting step, and a stretching step. In this case, the second embodiment is different from the first embodiment in that shaping using rollers is carried out in the rough rolling step, and the second embodiment is substantially the same as the first embodiment in terms of the subsequent steps between the annealing step and the stretching step. Accordingly, the rough rolling step will be described in detail.
Further,
A rough rolling device 30, which produces a contour molding material in the rough rolling step, includes a rolling mill 1 that includes a flat roller 10 and a grooved roller 20 as shown in
The grooved roller 20 includes three kinds (a plurality) of roller portions that have different roller radii and are formed on the outer peripheral portion 20a thereof. The grooved roller includes six small-diameter roller portions 21 for forming thick portions, three first large-diameter roller portions 22 having relatively small width, and two second large-diameter roller portions 23 having large width. Meanwhile, the grooved roller 20 is made of tool steel like the flat roller 10.
As shown in
As shown in
In this embodiment, the height h is set to 0.4 mm, the roller width W of the first large-diameter roller portion 22 is set to 1.0 mm, and W1/h is set to 2.5.
As shown in
The profile of the longitudinal section of the second large-diameter roller portion 23, which is taken along a plane passing through the axis P2, includes two end faces 23b and 23c that form obtuse angles together with the outer peripheral surfaces 21a of the small-diameter roller portions 21, and an outer peripheral surface 23a that connects between the end faces 23b and 23c. A roller width W2 between end edge portions (corners) 23g and 23h of the second large-diameter roller portion 23, which are formed by the outer peripheral surface 23a and the end faces 23b and 23c, respectively, is set to 4 mm in this embodiment.
The outer peripheral surface 23a of the second large-diameter roller portion 23 includes a middle surface (middle portion) 23d that is formed at the middle position of the second large-diameter roller portion 23 in the direction of the axis P2, and tapered surfaces 23i and 23j that are formed from both ends (fixed positions) 23e and 23f of the middle surface 23d toward both the end edges 23g and 23h of the second large-diameter roller portion 23, respectively.
More specifically, the middle surface 23d is formed to have the roller radius R4 and extends in the direction of the axis P2. The tapered surfaces 23i and 23j extend so as to decrease a roller radius from both the ends 23e and 23f of the middle surface 23d to both the end edges 23g and 23h and so as to be symmetric with respect to the middle surface 23d.
As described above, the middle surface 23d of the second large-diameter roller portion 23 protrudes further outward in the radial direction of the grooved roller 20 by a difference Δr(R4−R3) as compared to the outer peripheral surface 22a of the first large-diameter roller portion 22, and is extended (see
In this embodiment, Δr is set to 0.06 mm. That is, a ratio Δr/h between the height h and the difference Δr between the roller radius R4 of the middle surface 23d and the roller radius R3 of the outer peripheral surface 22a is set to 0.15, and a ratio W2/h between the height h and the roller width W2 of the second large-diameter roller portion 23 is set to 10.
Further, an angle θ between each of the tapered surfaces 23i and 23j, which are formed at both end portions of the middle surface 23d, and the middle surface 23d (an angle between each of the tapered surfaces and the axis P2) is set in the range of 0.1 to 5°.
The grooved roller 20 having the above-mentioned structure is disposed close to the flat roller so that the axis P2 is parallel to the axis P1 of the flat roller 10 and a gap between the outer peripheral surface 22a of the first large-diameter roller portion 22 and the outer peripheral surface of the flat roller 10 is about 0.2 mm, that is, a gap between the outer peripheral surface 21a of the small-diameter roller portion 21 and the outer peripheral surface of the flat roller 10 is about 0.6 mm.
Next, a method for producing a contour molding material C, which forms a contour strip G, using the rough rolling device 30 having the above-mentioned structure will be described.
First, as shown in
At the same time, a material feeding unit (not shown) inserts a plate material M into a gap that is formed between the flat roller 10 and the grooved roller 20.
As shown in
The width of the thin portion m1 of the contour molding material C, which is formed by the pressing of the first large-diameter roller portion 22, is 1.0 mm which is substantially equal to the roller width W1 of the first large-diameter roller portion 22. Further, the depth of the thin portion m1 from the outer peripheral surface of the thick portion is 0.4 mm which is substantially equal to the height h, and the thin portion m1 has a relatively small width. During the rolling, the plate material M is elongated in the longitudinal direction (the insertion direction of the plate material M), and compressive stress is generated by a difference between the elongated length of a portion of the thin portion m1 close to the middle portion in the width direction and the elongated length of the thick portion y adjacent to the thin portion m1. However, since deformation is suppressed by the thick portions y formed on both sides, the thin portion m1 is molded so as to have a uniform thickness. Accordingly, the upper surface of the thin portion m1 is formed in a planar shape.
In contrast, as the width of the thin portion m2 of the contour molding material C, which is formed by the pressing of the second large-diameter roller portion 23, is increased, pressure per unit area applied to the surface of the thin portion m2 is decreased. Accordingly, the thin portion m2 is apt to be thick as compared to the thin portion formed by the first large-diameter roller portion 22 having a small width. Further, since the width of the thin portion is large, the middle portion of the thin portion in the width direction is far from the thick portions. For this reason, the suppression of the above-mentioned thick portions does not affect the middle portion of the thin portion, so that a portion of the thin portion close to the middle portion in the width direction is apt to be formed thick.
In this case, the protruding height (h+Δr) of the second large-diameter roller portion 23 from the outer peripheral surface 21a of the small-diameter roller portion 21 is larger than the protruding height (h) of the first large-diameter roller portion 22, and the middle portion in the width direction is formed high. Accordingly, the pressing distance of the second large-diameter roller portion 23 is larger than that of the first large-diameter roller portion 22 by Δr. In addition, since the pressing distance is gradually decreased toward the boundary portions between the second large-diameter roller portion 23 and the thick portions due to the tapered surface 23i and 23j, the molded thin portion has the same thickness as the thickness of the thin portion molded by the first large-diameter roller portion 22 and has a uniform thickness in the width direction. That is, the width of the thin portion is 4.0 mm which is substantially equal to the roller width W2 of the second large-diameter roller portion 23, and the depth of the thin portion from the outer peripheral surface of the thick portion is 0.4 mm which is substantially equal to the height h.
Accordingly, it may be possible to form the thin portion so that the thin portion has the same thickness as the thickness of the thin portion molded by any one of large-diameter roller portions 22 and 23.
In this way, the plate material M is rolled by the flat roller 10 and the grooved roller 20, so that a contour molding material C having a high dimensional accuracy is produced.
Meanwhile, like in the first embodiment, the deviation Δt of plate thickness t at the thin portion m from a target value, the radii e of curvature at a corner formed by the side surface and the top surface of the thick portion and at a corner formed by the upper surface of the thin portion and the side surface of the thick portion, and the curvature D1 per meter-length of the contour molding material C are managed in the rough rolling step so that Δt is 0.01 mm or less, e is 0.15 mm or less, and D1 is 0.4 mm or less. Further, the rough rolling management value X, which is the product of these values, is obtained, and the rough rolling management value X is managed so as to be 5×10−4 or less.
Moreover, the difference |A−B| between the widths of the thick portions of both the side edge portions is managed in the subsequent slitting step so as to be 0.08 mm or less. In this case, since the thick portions y formed on both sides are cut in the second embodiment, the difference |A−B| is obtained by the measurement results of the width dimensions A and B of the thick portions y (see
As described above, according to the second embodiment, the pressing distance of the second large-diameter roller portion 23 becomes maximum at the middle surface 23d in the direction of the axis P2 and is gradually decreased toward both the end edges 23g and 23h from both the ends 23e and 23f of the middle surface 23d. Accordingly, even though the thickness of the middle portion of the thin portion m2 of the contour molding material C, which is pressed against the middle surface 23d, in the width direction is increased, it may be possible to form the thin portion m2 in a planar shape.
Therefore, it may be possible to work the upper surface of the thin portion m of the contour molding material C in a planar shape and to obtain excellent working accuracy.
In this way, it may be possible to appropriately select whether to form the outer peripheral surface of the roller portion having a uniform roller radius or to form the outer peripheral surface of the roller portion having different roller radii according to the widths and depths of the thin portions m (m1 and m2) of the contour molding material C, and to form the upper surfaces of the thin portions m (m1 and m2) in a planar shape. Specifically, if the width W of the thin portion satisfies “W/h≧3”, the thickness is difficult to increase at the middle portion in the width direction as in the case of the thin portion m1. Accordingly, it is preferable that the outer peripheral surface of the roller portion having a uniform roller radius be formed. Meanwhile, if “W/h3” is satisfied, the thickness is easy to increase at the middle portion in the width direction as in the case of the thin portion m2. Accordingly, it is preferable that the outer peripheral surface of the roller portion having different roller radii be formed.
Further, if a difference Δr/h between the roller radius R4 and the roller radius R3 is set in the range of 0.01 to 0.5, the depth of the thin portion m2 may be substantially equal to the height h.
Furthermore, since the roller radius of the outer peripheral surface 23a of the second large-diameter roller portion 23 is linearly decreased due to the tapered surfaces 23i and 23j in sectional view, it may be possible to easily form the second large-diameter roller portion 23.
Moreover, the tapered surfaces 23i and 23j are formed at the outer peripheral surface 23a of the second large-diameter roller portion 23 so as to be symmetric with respect to the middle surface 23d, and two small-diameter roller portions 21 are formed on both sides of the second large-diameter roller portion 23 so as to be adjacent to the second large-diameter roller portion. Accordingly, the pressing distance of the second large-diameter roller portion 23 in the direction of the axis P2 may be symmetric with respect to the middle surface 23d, and it may be possible to make the pressing distances of the two small-diameter roller portions 21, which are formed on both sides of the second large-diameter roller portion 23 so as to be adjacent to the second large-diameter roller portion, be equal to each other.
As shown in
Meanwhile, the operating procedure, the shapes of the respective components, the combination thereof, and the like described in the above-mentioned embodiments are illustrative. Therefore, various modifications may be made on the basis of design requests and the like without departing from the scope of the invention.
In the above-mentioned embodiments, the tapered surfaces 23i and 23j are formed so that a roller radius is changed to the roller radius R3 from the roller radius R4. However, as shown in
Moreover, a copper alloy of Cu-0.1% Fe-0.03% P has been used as the plate material M in the above-mentioned embodiments. However, for example, a copper alloy (Cu-0.15% Sn-0.006% P, Cu-0.02% Zr, Cu-2.3% Fe-0.12% Zn-0.03% P, C1020 (oxygen-free copper), or C1220 (phosphorous-deoxidized copper)), which is a material having high conductivity, other than the copper alloy may be worked to good effect. Further, a copper alloy (Cu-0.7% Mg-0.005% P, Cu-0.5% Sn-1.0% Zn-2.0% Ni-0.5% Si, or Cu-0.3% Cr-0.1% Zr-0.02% Si), which is a material having high strength, may be worked to good effect.
Meanwhile, it is thought that the increase of the thickness of the thin portion of the contour molding material depends on not only the dimensions of the contour molding material but also the material of the contour molding material. That is, the values of the above-mentioned w/h and Δr/h are not limited to those of the above-mentioned embodiments, and are appropriately set according to the material of the contour molding material.
The invention may be used as a technique that produces a contour strip used for a lead frame of a LED, a power transistor, or the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-135987 2008 | May 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/002216 | 5/20/2009 | WO | 00 | 11/9/2010 |
