JP5073357B2 - Metal plate cutting method and cutting apparatus - Google Patents

Description

  The present invention relates to a method for cutting a metal plate that can cut a metal plate manufactured by rolling or forging without causing a defective quality of a cut surface in the transport line, and a cutting apparatus used therefor.

  A metal plate manufactured from a raw material through hot rolling, cold rolling or forging is cut at the front end portion, the rear end portion, and the side surface portion to become a metal plate as a final product. As these cutting operations, a method using heat or electric energy such as mechanical cutting represented by shear or gas cutting or plasma cutting is generally employed. Among them, the method using mechanical cutting has the highest cutting efficiency.

  In mechanical cutting represented by the use of a shear, a metal plate, which is the material to be cut, is placed between the upper blade and the lower blade, and only one of the blades or both the upper and lower blades are oriented in the direction of the material to be cut. The most general method is to apply a shearing force to the material to be cut by driving it. At this time, if the distance (clearance) between the upper blade and the lower blade in the direction of the metal plate conveyance line (hereinafter also referred to as “blade clearance”) is not set properly, There is “sag” drawn by the blade in the vicinity of the cutting line on the surface of a certain metal plate, and “burr” (hereinafter also referred to as “kaeri”) in the vicinity of the cutting line on the surface on the opposite side of the metal plate. Furthermore, a quality defect such as “a defect in the perpendicularity of the cut surface” occurs on the cut surface of the metal plate.

  Therefore, the clearance between the blades needs to be determined to an appropriate value in consideration of the thickness and strength of the metal plate as the material to be cut and the degree of wear of the blade.

  For example, Patent Document 1 discloses a blade clearance adjusting mechanism, and Patent Document 2 discloses a blade clearance adjusting method.

  The technique disclosed in Patent Document 1 is a shear that restrains one of the upper blade and the lower blade in the vertical direction and allows the other blade to move up and down. This invention relates to a mechanism for adjusting the clearance between the blades by providing a cotter having a gradient obliquely intersecting with the threading direction on the back surface of the blade and sliding the blade in a direction perpendicular to the sheeting direction along this gradient. .

  Further, in Patent Document 2, a clearance between the blades is determined in advance according to the material of the metal strip, a clearance signal determined according to each material is given to the cutting device, and the clearance between the blades is set. Is disclosed.

  However, in the technique disclosed in the above patent document, the clearance between the blades is constant without changing at any position of the blades.

JP-A-8-276313 (Claims and paragraph [0009]) JP-A-6-39622 (Claims and paragraph [0010])

  In the cutting process of the metal plate, materials to be cut having various sizes are cut according to the size of the final product. That is, the cutting length of the material to be cut varies from approximately the same as the entire length of the blade to very short one.

  Generally, in the cutting step, the material to be cut is brought to one side surface (hereinafter also referred to as “reference side surface”) of the conveyance line and cut by a cutting device. For this reason, the portion corresponding to the position of the reference side surface of the blade of the cutting device is always used for cutting, whereas the other side surface opposite to the reference side surface of the transport line (hereinafter referred to as “reverse side”). The portion corresponding to the position of “reference side surface”) is used for cutting only when the cutting line length of the material to be cut is long (that is, in the case of a wide material to be cut).

  Therefore, the part of the blade corresponding to the position of the reference side surface is always used, and the wear of the blade progresses quickly, whereas the part of the blade corresponding to the position of the anti-reference side face does not progress so much. For this reason, if the cutting of the workpiece is continued for a long time after replacing the blade by maintenance of the cutting device, the portion close to the position of the anti-reference side when cutting the workpiece with a long cutting line length However, the cut surface of the portion close to the position of the reference side surface is liable to cause poor quality of the cut surface such as drooling, burr, or perpendicularity of the cut surface.

  The present invention has been made in view of the occurrence of the problems as described above, and the problem is that even if it is cut for a long time, the portion near the reference side surface and the vicinity of the anti-reference side surface of the metal plate that is the material to be cut The cutting method which can suppress generation | occurrence | production of the quality defect of the cut surface in this part, and the cutting device for it are provided.

  In order to solve the above-mentioned problems, the present inventors have repeatedly researched and developed a cutting method and a cutting apparatus that improve the quality of the cut surface of a metal plate that is a material to be cut, and the following (a) to (d) The present invention was completed by obtaining the above knowledge.

  (A) When the clearance between the blades (number 3 in FIGS. 1 and 3 described later) is large or when the blades are worn, the crack generation position near the lower blade is closer to the upper blade side, and when the cutting is completed Since the “burr” generated on the surface of the metal plate is increased, a man-hour for removing the burr is generated. Further, when blade wear progresses, burr can be suppressed to some extent by reducing the clearance between the blades.

  (B) When the clearance between the blades is small, the burr becomes small, but cracks are likely to occur near the cut surface on the lower surface of the metal plate. Further, the progress of wear of the upper blade and the lower blade is increased, and the replacement frequency of the blade is increased.

  (C) a blade portion corresponding to the position of the reference side surface (number 11 in FIG. 2 and the like) and a blade portion corresponding to the position of the counter-reference side surface (number 12 in FIG. 2); In a cutting device with the same clearance between the blades, if the cutting clearance is adjusted to the optimum value and cutting of the workpiece is continued, burr will be generated at the portion of the workpiece close to the reference side surface where the blade wears quickly. It becomes easy to do.

  (D) By adjusting the inter-blade clearance in the part of the blade corresponding to the position of the reference side surface, even if the blade is worn, the occurrence of burr in the part of the material to be cut close to the reference side surface position can be suppressed. The cutting of the material to be cut can be continued without performing the maintenance. Therefore, by making the clearance between the blades at the position of the reference side smaller than the clearance between the blades at the position of the non-reference side, it is possible to suppress the occurrence of burr at the part of the workpiece close to the position of the reference side.

  The present invention has been completed based on the above findings, and the gist of the present invention is a metal plate cutting method shown in (1) below and a metal plate cutting device shown in (2) and (3). is there.

(1) The metal plate is brought close to one side surface of the conveying line, and the cutting surface is cut by the upper blade positioned above the conveying line and the lower blade positioned below the conveying line with the side surface as a reference side surface. Is a cutting method of a metal plate that cuts in a direction substantially perpendicular to the direction of the transport line,
After the maintenance of the upper blade and / or the lower blade, before the next maintenance, the clearance between the upper blade and the lower blade at the position of the reference side is sequentially narrowed to cut the metal plate. A method for cutting a metal plate.

(2) A cutting device for cutting a metal plate along a cutting line that is substantially orthogonal to the direction of the transport line, with the metal plate brought close to one side surface of the transport line as a reference side surface. ,
An upper blade positioned above the transport line and a lower blade positioned below the transport line;
And a blade lifting mechanism for cutting by applying a shear force to the metal plate by raising the lowering and / or lower blade and upper blade,
The clearance between the upper blade and the lower blade at the position of the reference side is smaller than the clearance between the upper blade and the lower blade at the position of the other side opposite to the reference side. Cutting device.

(3) A cutting device for cutting a metal plate along a cutting line that is substantially orthogonal to the direction of the transport line, with the metal plate brought close to one side surface of the transport line, with the side surface as a reference side surface. ,
An upper blade positioned above the transport line and a lower blade positioned below the transport line;
A blade lifting mechanism for cutting by applying a shear force to the metal plate by raising the lowering and / or lower blade and upper blade,
A clearance adjusting mechanism capable of making the clearance between the upper blade and the lower blade at the position of the reference side surface smaller than the clearance between the upper blade and the lower blade at the position of the other side opposite to the reference side surface; A metal plate cutting device comprising:

  In the present invention, the “clearance between the upper blade and the lower blade” means the distance between the upper blade and the lower blade in the direction of the metal plate conveyance line (number 3 in FIGS. 1 and 3 described later). In the following description, it is also referred to as “blade clearance”.

“Metal plate” means a metal plate having a thickness of 50 mm or less. This is because if the plate thickness exceeds 50 mm, it becomes impossible to ensure good cut surface quality, and it becomes difficult to apply the present invention.
Further, “the cutting line is substantially perpendicular to the direction of the transport line” means that the angle formed by the cutting line and the direction of the transport line is in the range of 85 to 95 degrees. This is because if the angle between the cutting line and the direction of the conveying line is outside the above range, the product cannot be shipped as a product, and the significance of using the present invention is reduced.

  “Sequentially narrowing” means narrowing as the blade usage time elapses.

  According to the metal plate cutting method of the present invention, the blade maintenance frequency is increased by sequentially reducing the clearance between the blades at the position of the reference side surface after the blade maintenance until the next maintenance. In addition, it is possible to suppress the occurrence of poor quality of the cut surface in the metal plate portion close to the reference side surface position and the metal plate portion close to the anti-reference side surface position, and to have a good cut surface quality along the entire cutting line. Can be obtained. The metal plate cutting device of the present invention has a clearance adjustment mechanism that can make the clearance between the blades at the position of the reference side surface smaller than the clearance between the blades at the position of the other side surface facing the reference side surface. It is the most suitable cutting device for the implementation of the law.

  As described above, the method of the present invention brings the metal plate to one side surface of the conveyance line, and uses the side surface as a reference side surface to cut the metal plate with the upper and lower blades located above and below the conveyance line. A method of cutting a metal plate in which the line is cut in a direction substantially perpendicular to the direction of the conveying line, and after the maintenance of the upper blade and / or the lower blade, until the next maintenance, This is a method of cutting a metal plate in which the clearance between the blades at the position is sequentially narrowed to cut the metal plate. In addition, the apparatus of the present invention has a shearing force applied to the metal plate by raising and lowering the upper blade and / or the lower blade in the vertical direction, and the upper blade located above and below the metal plate conveyance line. And a blade lifting mechanism for cutting with a clearance, and a clearance adjustment mechanism capable of making the clearance between the blades at the position of the reference side smaller than the clearance between the blades at the position of the other side facing the reference side. It is a metal plate cutting device. Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side view (transverse sectional view) of an upper blade and a lower blade in a shear cutting device. FIG. 2 is a plan view (top view) of an upper blade and a lower blade in the shear cutting device, and shows a plan view of a cut surface along A ₁ A ₂ A ₃ A ₄ in FIG.

  As shown in the figure, in a general cutting device, an upper blade 1 held by an upper blade holder 5 via a liner 4 and a lower blade 2 held by a lower blade holder 6 via a liner 4. However, it is attached to the cutting device with a clearance 3 between the upper blade 1 and the lower blade 2. Since the blade is worn by cutting a material to be cut such as a metal plate, it is appropriately replaced. When exchanging the blade, the upper blade 1 and / or the lower blade 2 are removed from the cutting apparatus main body together with the upper blade holder 5 and the lower blade holder 6, and a polished blade or a new blade is replaced with the upper blade holder 5 and / or A method of attaching to the lower blade holder 6 and then attaching to the cutting device main body is common. Further, as shown in FIG. 2, the inter-blade clearance 31 at the position 11 on the reference side surface and the inter-blade clearance 32 at the position 12 on the non-reference side surface are generally the same.

  FIG. 3 is a diagram schematically showing the outline of shear cutting of a metal plate. FIG. 3A shows a state before starting cutting, FIG. 3B shows a state immediately after starting cutting, FIG. ) Represents the state after completion of cutting.

  As shown in FIG. 3A, the clearance 3 between the upper blade 1 and the lower blade 2 is determined before the cutting in consideration of the thickness and strength of the metal plate 7 to be cut and the wear state of the blade. Is set in advance. Thereafter, as shown in FIG. 2B, when the upper blade 1 is lowered and a shearing force is applied to the metal plate 7, the upper surface of the metal plate 7 near the corner portion of the upper blade 1 and the corner portion of the lower blade 2. Cracks 8 are generated on the lower surface of the nearby metal plate 7, respectively. When the upper blade 1 is further lowered, the cracks 8 formed on the upper surface and the lower surface of the metal plate 7 meet to complete the cutting of the metal plate, as seen in FIG.

(1) Relationship between the clearance between the blades at the time of cutting and the quality of the cut surface FIG. 4 is a diagram schematically showing a quality defect of the cut surface of the metal plate, and FIG. The situation (b) of FIG. 2 represents the occurrence of cracks on the lower surface of the metal plate.

1) When the clearance between the blades is large When the clearance 3 between the blades is large, the generation position of the crack 8 generated in the vicinity of the lower blade 2 is closer to the upper blade 1 side than the lower blade 2, and the cutting of the metal plate 7 is completed. Sometimes, as shown in FIG. 4A, the “kaeri 10” becomes large, and a care process for removing the kaeri 10 is required. In addition, even when the wear of the blade progresses, the occurrence position of the crack 8 generated in the vicinity of the lower blade 2 is closer to the upper blade 1 side than the lower blade 2, and the burr 10 becomes larger. When the wear of the blade has progressed, the occurrence of burr 10 can be suppressed to some extent by reducing the clearance 3 between the blades. Note that reference numeral 9 in FIG. 9 indicates “sag” generated when the material near the upper surface of the metal plate is drawn by the upper blade 1.

2) When the clearance between the blades is small When the clearance 3 between the blades is small, the burr 10 is small, but as shown in FIG. 4 (b), near the cutting surface of the lower surface of the metal plate 7 that is the material to be cut. “Crack 13” tends to occur. In addition, when the clearance 3 between the blades is small, the progress of wear of the upper blade and the lower blade is accelerated, so that it is necessary to frequently replace the blade.

  Considering the influence of the clearance between the blades on the quality of the cut surface of the material to be cut, the progress of blade wear, and the maintenance frequency of the blade as described above, the clearance between the blades is 5 of the thickness 14 of the metal plate 7. It is preferable to set it in a range of ˜15%.

(2) Setting of clearance between blades In general, in a shear cutting process of cutting a metal plate stretched from a material by rolling or forging in a direction substantially perpendicular to the longitudinal direction at the front end portion, rear end portion or midway portion Are often cut close to one side surface (reference side surface) of the transport line. In this case, depending on the length of the cutting line, that is, the length of the width of the metal plate that is the material to be cut, a blade portion that is frequently used for cutting and a blade portion that is not frequently used are generated.

  FIG. 5 is a plan view of the upper and lower blades and the metal plate in the shear cutting device when cutting a metal plate having a short cutting line. Since the width of the metal plate 7 is narrow and therefore the cutting lines indicated by the numbers 71 to 72 are short, the upper blade 1 and the lower blade 2 in the vicinity of the position 11 on the reference side surface are used for cutting the metal plate 7. The upper blade 1 and the lower blade 2 near the reference side surface position 12 are not used for cutting.

  On the other hand, FIG. 6 is a plan view of the upper and lower blades and the metal plate in the shear cutting device when cutting a metal plate having a long cutting line. Since the width of the metal plate 7 is wide and therefore the cutting lines (71 to 72) are long, not only the upper blade 1 and the lower blade 2 in the vicinity of the position 11 on the reference side surface but also the upper blade 1 in the vicinity of the position 12 on the anti-reference side surface and The lower blade 2 is also used for cutting the metal plate 7.

  In this way, the blade existing in the vicinity of the reference side surface position 11 is frequently used, whereas the blade existing in the vicinity of the non-reference side surface position 12 is a metal plate having a long cutting line (71 to 72). Since it is used only when cutting 7, the frequency of use is reduced. Therefore, the amount of wear differs between the blade that exists in the vicinity of the reference side surface position 11 and the blade that exists in the vicinity of the anti-reference side surface position 12, and as a result, the metal plate 7 having a long cutting line (71 to 72) is formed. In the case of cutting, there will be a difference in the quality of the cut surface along the cut surface.

  In the case of a cutting device in which the blade clearances 31 and 32 are the same for the blade positioned in the vicinity of the reference side surface position 11 and the blade positioned in the vicinity of the counter-reference side surface position 12, the clearance between the blades is adjusted to an optimum value. If the cutting of the metal plate is continued, the burr 10 is likely to occur on the metal plate in the vicinity of the reference side surface position 11 where the blade wears quickly.

  As a countermeasure, if the clearance 31 between the blades in the vicinity of the reference side surface position 11 is adjusted, the occurrence of the burr 10 in the vicinity of the reference side surface position 11 can be suppressed even if the blade is worn. It is possible to continue cutting the metal plate 7 without performing the above. Therefore, the burr 10 in the vicinity of the reference side surface position 11 is made by making the inter-blade clearance 31 of the blade located in the vicinity of the reference side surface position 11 smaller than the inter-blade clearance 32 of the blade in the vicinity of the counter-reference side surface position 12. Can be suppressed.

(3) Method for changing the clearance between the blades at the reference side surface position and the anti-reference side surface position The method for adjusting and changing the clearance between the blades at the reference side surface position and the clearance between the blades at the anti-reference side surface position includes the following methods.

1) A method in which the thickness of the blade is different between the reference side surface position and the anti-reference side surface position, and the blade thickness between them is processed into a taper shape. FIG. It is a figure which shows the example which adjusts and changes. The figure shows an example in which the clearance 3 between the blades is adjusted by changing the thickness of the upper blade 1 in a tapered shape between the reference side surface position 11 and the non-reference side surface position 12. Yes.

2) A method in which the thickness of the liner is different between the reference side surface position and the anti-reference side surface position, and the thickness of the liner in between is changed to a taper shape. FIG. It is a figure which shows the example which adjusts and changes clearance. In the figure, the thickness of the liner 4 provided between the upper blade 1 and the upper blade holder 5 is changed into a tapered shape between the reference side surface position 11 and the anti-reference side surface position 12 and processed. Thus, an example of adjusting and changing the inter-blade clearance 3 is shown.

3) A method in which the thickness of the blade holder is made different between the reference side surface position and the anti-reference side surface position, and the thickness of the blade holder in between is changed into a taper shape. It is a figure which shows the example which adjusts and changes a clearance. This figure shows an example in which the clearance 3 between the blades is adjusted by changing the thickness of the upper blade holder 5 in a tapered shape between the reference side surface position 11 and the anti-reference side surface position 12. ing.

4) Method of processing the blade, liner and blade holder in a tapered shape The thickness of the upper blade 1 or the lower blade 2, the liner 4, and the upper blade holder 5 or the lower blade holder 6 is set to the reference side surface position 11 and the anti-reference side surface. It is possible to adjust and change the clearance 3 between the blades by machining them in a tapered shape with respect to the position 12 and attaching them in combination.

  In addition to the method of making the clearance between the blades at the reference side surface narrower than the clearance between the blades at the anti-reference side surface position as described above, the clearance between the blades at the reference side surface position is anti-referenced to the main body of the cutting device as described below. You may provide the clearance adjustment function which can be made smaller than the clearance between the blades of a side surface position. When such equipment is used, an optimum inter-blade clearance can be secured as appropriate according to the usage time of the cutting device.

(4) Preferred clearance adjustment mechanism The method for changing the clearance between the blades 1) to 4) described above is performed after the blade or the like is processed in a taper shape and attached to the cutting device (that is, blade maintenance). Until the blade is replaced (that is, until the next blade maintenance is performed), the clearance between the blades in the vicinity of the reference side surface position and in the vicinity of the counter-reference side surface position cannot be changed.

  The clearance between the blades originally has an optimum value, and when the clearance between the blades at the reference side surface position is made narrower than the optimum value, there is a disadvantage that the blade is worn too quickly. Therefore, if the cutting apparatus can be operated and adjusted so that the clearance between the blades at the reference side surface position is further narrowed before the burr occurs at the portion of the metal plate corresponding to the reference side surface position, the wear of the blade as described above can be achieved. It is possible to continue the cutting of the metal plate while ensuring a good cut surface state while avoiding the early progress of the step.

  FIG. 10 is a diagram illustrating an example in which the clearance between the blades is adjusted and changed depending on the structure of the main body of the shear cutting device. The figure shows that the entire upper blade 1, liner 4 and upper blade holder 5 and / or the entire lower blade 2, liner 4 and lower blade holder 6 are inclined from the direction perpendicular to the metal plate conveyance line, The example which adjusts and changes the clearance 3 between the blades of the upper blade 1 and the lower blade 2 is shown.

  Examples of the adjustment mechanism that enables adjustment of the clearance between the blades include the following mechanisms.

  1) The side surface of the support member provided at the reference side surface position 11 and the non-reference side surface position 12 of the upper blade holder 5 that holds the upper blade 1 and / or the lower blade holder 6 that holds the lower blade 2 is connected to a metal plate conveying line. And an adjustment mechanism having a wedge-shaped member that supports the inclined surface of the supporting member so as to be slidable and can be moved up and down in the vertical direction. By adjusting the height position of the wedge-shaped member, the upper blade 1 and / or the lower blade 2 is inclined from the direction perpendicular to the metal plate conveyance line, and the clearance 31 between the blades at the reference side surface position and the anti-reference side surface The clearance 32 between the blades at the position can be arbitrarily adjusted and changed even during the cutting operation.

  2) The side surfaces of the support members provided at the reference side surface position 11 and the anti-reference side surface position 12 of the upper blade holder 5 that holds the upper blade 1 and / or the lower blade holder 6 that holds the lower blade 2 are arranged in the direction of the conveying line. An adjustment mechanism having movable screws and / or hydraulic cylinders can be used. By adjusting the position of the screw and / or hydraulic cylinder in the conveying line direction, the upper blade 1 and / or the lower blade 2 is inclined from the direction orthogonal to the conveying line of the metal plate, and the clearance 31 between the blades at the position of the reference side surface and The inter-blade clearance 32 at the position of the opposite reference side can be arbitrarily adjusted and changed even during the cutting operation.

  By using the cutting device having the above-described mechanism, the metal plate 7 while the blade clearance 31 at the position 11 on the reference side surface is sequentially narrowed after the blade maintenance is performed until the next maintenance is performed. The cutting can be continued.

  In this case, immediately after the maintenance of the blade, it is preferable that the clearance 31 between the blades at the position 11 on the reference side and the clearance 32 between the blades at the position 12 on the anti-reference surface are the same. Immediately after blade maintenance, the blade state is uniform at any position of the blade, and by making the clearance between the blades constant in the longitudinal direction of the blade, cutting can be performed in the best condition. is there.

  According to the metal plate cutting method of the present invention, the blade maintenance frequency is increased by sequentially reducing the clearance between the blades at the position of the reference side surface after the blade maintenance until the next maintenance. In addition, it is possible to suppress the occurrence of poor quality of the cut surface in the metal plate portion close to the reference side surface position and the metal plate portion close to the anti-reference side surface position, and to have a good cut surface quality along the entire cutting line. Can be obtained. The metal plate cutting device of the present invention has a clearance adjustment mechanism that can make the clearance between the blades at the position of the reference side surface smaller than the clearance between the blades at the position of the other side surface facing the reference side surface. It is the most suitable cutting device for the implementation of the law. Thus, the present invention can be widely applied as a cutting method and a cutting apparatus that can ensure good cut surface quality in a cutting process of a metal plate including a thick plate material.

Explanation of symbols

1: upper blade, 2: lower blade, 3: clearance between blades, 31: clearance between blades at the position of the reference side surface, 32: clearance between blades at the position of the anti-reference side surface, 4: liner, 5: upper blade holder, 6 : Lower blade holder, 7: Material to be cut (metal plate), 8: Crack, 9: Who, 10: Burl, 11: Position of reference side, 12: Position of anti-reference side, 13: Crack, 14: Thickness 71, 72: Start point and end point of cutting line

It is a side view (cross-sectional view) of the upper blade and lower blade in a shear cutting device. Is a plan view of the upper blade and lower blade (top view) in the shear cutting device, showing a plan view of a cutting surface along the A ₁ A ₂ A ₃ A ₄ in FIG. It is a figure which shows the outline | summary of shear cutting | disconnection of a metal plate typically, The figure (a) is the state before a cutting | disconnection start, The figure (b) is the state immediately after the cutting start, The figure (c) is cutting completion. Each subsequent state is represented. It is a figure which shows typically the quality defect of the cut surface of a metal plate, The figure (a) shows the generation | occurrence | production state of a drool and burr, and the figure (b) shows the generation | occurrence | production state of the crack in a lower surface. It is a top view of the upper blade and lower blade in a shear cutting device, and a metal plate in the case of cutting a metal plate with a short cutting line. It is a top view of the upper blade and lower blade in a shear cutting device, and a metal plate in the case of cutting a metal plate with a long cutting line. It is a figure which shows the example which adjusts clearance between blades with the upper blade of a shear cutting device. It is a figure which shows the example which adjusts and changes the clearance between blades with the liner of the upper blade of a shear cutting device. It is a figure which shows the example which adjusts and changes the clearance between blades with the upper blade holder of a shear cutting device. It is a figure which shows the example which adjusts and changes the clearance between blades with the structure of the main body of a shear cutting device.

Claims (3)

The metal plate is brought close to one side of the transfer line, and the cut line is cut by the upper blade positioned above the transfer line and the lower blade positioned below the transfer line. A method of cutting a metal plate that is cut in a direction substantially perpendicular to the direction of
After the maintenance of the upper blade and / or the lower blade, before the next maintenance, the clearance between the upper blade and the lower blade at the position of the reference side is sequentially narrowed to cut the metal plate. A method for cutting a metal plate. A cutting device for cutting the metal plate along a cutting line substantially perpendicular to the direction of the transport line, with the side surface as the reference side surface in a state where the metal plate is brought close to one side surface of the transport line,
An upper blade positioned above the transport line and a lower blade positioned below the transport line;
And a blade lifting mechanism for cutting by applying a shear force to the metal plate by raising the lowering and / or lower blade and upper blade,
The clearance between the upper blade and the lower blade at the position of the reference side is smaller than the clearance between the upper blade and the lower blade at the position of the other side opposite to the reference side. Cutting device. A cutting device for cutting the metal plate along a cutting line substantially perpendicular to the direction of the transport line, with the side surface as the reference side surface in a state where the metal plate is brought close to one side surface of the transport line,
An upper blade positioned above the transport line and a lower blade positioned below the transport line;
A blade lifting mechanism for cutting by applying a shear force to the metal plate by raising the lowering and / or lower blade and upper blade,
A clearance adjusting mechanism capable of making the clearance between the upper blade and the lower blade at the position of the reference side surface smaller than the clearance between the upper blade and the lower blade at the position of the other side opposite to the reference side surface; A metal plate cutting device comprising:

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