Method for automatically positioning blanks and calculating related
By automatically positioning the blank parts in the belt and optimizing its orientation and offset, the problem of high waste rate during the cutting process is solved, and more efficient production and lower environmental impacts are achieved.
Patent Information
- Application Number
- CN202280097118.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-17
- Publication Date
- 2025-01-28
AI Technical Summary
During the manufacturing process, the material left in the strip after cutting the blank is wasted, resulting in a high waste rate, affecting production efficiency and environmental impact.
The position of automatic positioning of the blank parts in the belt is automatically located by the computerized method, and the orientation and horizontal offset of the blank parts are optimized to reduce the waste rate and calculate the cost of material during the tailoring process.
Effectively reduce the waste rate, improve production efficiency, reduce the cost of cutting operations, and reduce the impact on the environment.
Smart Images
Figure CN119384650A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the manufacture of blanks and in particular to the manufacture of blanks cut from a generally longitudinally extending rectangular flat strip of material. Background Art
[0002] In many material manufacturing processes of typically flat materials, the continuous nature of the manufacturing process means that the final manufactured product is in the form of a long strip extending generally in a longitudinal direction. This is the case, for example, in the production of flat sheet metals, such as flat steel products or flat aluminum products. This is also the case in the pulp and paper industry or in the manufacture of fabrics and textiles. Such strips are often conditioned by winding them into coil form in order to efficiently store them and transport them.
[0003] A common way to use the material in a subsequent conversion process is to cut shapes with a predetermined contour from the strip. For example, a metal blank may be cut in the case of a metal strip, or a fabric or textile in the fashion industry. In the case of a metal strip, this operation is called blanking, and the subsequent product is a metal blank, i.e. a substantially flat piece of metal with a predetermined contour, suitable for use in a subsequent conversion process. This operation may be performed, for example, by stamping, water jet cutting, oxygen cutting or laser cutting.
[0004] For the sake of simplicity, the term "blank" will be used hereinafter, but, as will be readily understood, the field of application of the invention is not limited to metallic materials.
[0005] The material remaining in the strip after the blanks have been cut out is designated as scrap. Scrap is the discarded material generated during the blanking process and should be kept to a minimum in order to optimize productivity, to minimize environmental impact and to minimize the costs of the blanking operation. In the case of environmental impact, the production process used to make the raw material strip itself has an environmental footprint, such as the emission of CO 2 By minimizing waste materials and therefore maximizing the overall output of the industrial process, the environmental impact can be kept as low as possible. Summary of the invention
[0006] In the present invention, the term "cost" generally refers to, for example, environmental cost, productivity cost or financial cost.
[0007] In the present invention, the arrangement is as follows: a strip from which two blanks are cut, each having a predetermined profile and each having a fixed orientation towards the longitudinal direction and a given offset to each other in the transverse direction. The positioning of the two blanks relative to each other in the longitudinal direction will determine a pattern, which is then repeated as long as the strip extends in the longitudinal direction. The fact that the orientation of the blanks is fixed may be an industrial limitation, for example due to anisotropy in the case of metallic materials, such as obtained from the self-rolling process in the case of steel or aluminum; the fact that the orientation of the blanks is fixed may also be linked to other considerations, such as patterns in the textile industry.
[0008] The present invention aims to provide an automated method of positioning the given blank in the strip in an optimal material usage configuration and calculating the subsequent scrap rate. The scrap rate is defined as the ratio between the scrap generated by the blanking process and the total amount of strip material used.
[0009] The present invention also aims to provide an automated method for calculating blank costs associated with material usage in a blanking operation.
[0010] By providing an optimized computer-implemented method for positioning blanks, calculating scrap rates and material costs, the present invention allows efficient design and cost assessment of blanking processes. In addition, automation of the operations allows them to be used in subsequent optimization routines. For example, automation of the operations can be used in subsequent routines to find the best combination in blank orientation and lateral offset to minimize overall scrap.
[0011] The object of the invention is achieved by providing a method for computerized positioning of two blanks in a strip according to claim 1, optionally including the features of claims 2 to 4, by providing a computerized scrap rate calculation method according to claim 5, and by providing a computerized blank calculation method according to claim 6, optionally including the features of claim 7. The object of the invention is also achieved by providing a computer program according to claim 8 and a computer-readable storage medium according to claim 9. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will now be described and illustrated in detail by way of example without introducing limitations, with reference to the following accompanying drawings:
[0013] - Figure 1 is an overview of the configuration of the positioning of the two blanks in the strip, the longitudinal direction is indicated by the arrow marked "L", while the transverse direction is indicated by the arrow marked "T",
[0014] - Figure 2A and Figure 2B The following are diagrams showing the calculation methods of dAA and dBB,
[0015] - Figure 3A and Figure 3B The following are diagrams showing the calculation methods of dBA and dBA respectively.
[0016] - Figure 4 is to determine dA on more complex shapes i Another example of a value of type A,
[0017] - Figure 5A is an example of determining dAA, dBB, dBA, and dBA on a more complex shape, and Figure 5B yes Figure 5A Illustration of the positioning of blanks A and B in the strip,
[0018] - Fig. 6A , Figure 6B and Fig. 7A , Figure 7B On blanks with the same shape but different orientations, follow the same Figure 5A and Figure 5B The same principle,
[0019] - Figure 8 and Fig. 9 A specific embodiment of the invention is shown, in which the blanking tolerance and the width tolerance of the strip are taken into account to calculate the scrap rate and the blank cost. DETAILED DESCRIPTION
[0020] In the present invention, reference is made to Figure 1 , the longitudinal direction refers to the main direction of extension of the strip 1, and the transverse direction refers to the perpendicular direction in the plane to the longitudinal direction. The strip 1 also extends in the transverse direction Y over a limited width between the two parallel edges 2 and 3 and over a width W in said direction.
[0021] The strip 1 has a top side and a bottom side, also referred to as the top and bottom sides. All the accompanying figures are two-dimensional top views, in which only the top side is visible. The distance between the top and bottom sides is designated as the thickness of the strip. This thickness can be measured, for example, using a micrometer, the spindle and anvil of which are placed on the top and bottom sides.
[0022] In the following description and claims, the terms "longitudinal" and "horizontal" have the same meaning, and the terms "lateral" and "vertical" have the same meaning. The terms "left" and "right" will be used in the subsequent description and claims, and they refer to the longitudinal direction, i.e., the direction along which the left and right sides of the axis are parallel to each other. Figure 1The terms "upward" (and "above", "higher", etc.) and "downward" (and "below", "lower", etc.) will be used in the subsequent description and claims to refer to the relative positions in the lateral direction, i.e., along the direction indicated by the arrow "L". Figure 1 The "T" arrows mark the relative positions of more posterior and more anterior directions.
[0023] Reference Figure 1 , a first blank A having a first contour and a second blank B having a second contour are cut from the strip 1 .
[0024] Blank B is offset in the transverse direction from blank A by a transverse offset dy, which is defined as the transverse height difference between the lowest point of the blank profile of B in the transverse direction and the lowest point of the blank profile of A in the transverse direction.
[0025] The first object of the invention is to determine in an automated manner how to position blanks A and B in a strip 1 so as to use the least possible amount of material. This is the case when a first set of blanks A and B contacts the next set of blanks A and B at at least one point without overlapping. The subsequent pattern is then repeated along the longitudinal direction. There are several possible different ways of positioning blanks A and B in order to optimize material use. Each of these configurations is equivalent in terms of material use. The invention is intended to identify only one such possible configuration.
[0026] The missing elements for positioning blanks A and B are the following two: the spacing Δ in the longitudinal direction between the left end of the A blank and the left end of the adjacent B blank to its right 1 ; and the spacing Δ between the left end of the B blank and the left end of the adjacent A blank on its right side 2 Once the spacing has been determined, the blank can be positioned in the strip and the scrap rate and blanking material costs can then also be calculated, as will be described further.
[0027] Spacing Δ 1 and spacing Δ 2 The shapes and inner dimensions of A and B along the longitudinal direction, as well as the interaction between blank A and blank B in the longitudinal direction are taken into account.
[0028] In order to optimize the calculation time, the inventors have developed the following method: the method involves only the internal distance between the vertex and the edge of each individual blank A and B in the longitudinal direction, and the method involves the interaction between blank A and blank B in the longitudinal direction only at the points in the width where the vertex of blank A or B is located.
[0029] Since the number of vertices per blank is discrete and usually very limited, the method of the invention allows a very fast calculation of the scrap rate.
[0030] Reference Figure 2A and Figure 2B , use the X, Y coordinate system to locate the vertices and contours of blanks A and B. The X axis is parallel to the longitudinal direction of the strip, while the Y axis is parallel to the transverse direction of the strip. By convention, blank A is located in the coordinate system so that the leftmost point of blank A is at X=0 and the lowest point of blank A is at Y=0. Blank B is located so that the leftmost point of blank B is at X=0 and the lowest point of blank B is at Y=dy.
[0031] The blank contours of A and B are connected by vertices A and B respectively. 1 , A 2 , A 3 , A 4 and B 1 , B 2 , B 3 Each vertex A i By its coordinates (XA i , YA i ) and each vertex B i By its coordinates (XB i , Y.B. i ) logo.
[0032] For clarity, blanks A and B in the figure have simple shapes with long straight edges. However, the method is applicable to any two-dimensional contour. In the case of contours including curved edges, these contours can be approximated by a series of smaller straight line segments, thereby defining a set of vertices and connecting edges.
[0033] In the general case, a blank A is thus composed of its set of p vertices {A 1 , ..., A P}, and the blank B is represented by the set of its q vertices {B 1 , ..., B q} represents, where p and q are integers equal to or greater than 3.
[0034] In order to determine Δ 1 and Δ 2 First, it is necessary to calculate the maximum longitudinal dimensions dAA and dBB of blank A and blank B respectively, and when the blanks are superimposed, calculate the maximum longitudinal offset dAB from blank A to blank B and the maximum longitudinal offset dBA from blank B to blank A respectively (see Figure 3A and Figure 3B ).
[0035] This is accomplished by implementing the following steps:
[0036] -For each vertex A i Calculate the distance dA i A, the distance dA i A is defined as the vertex A i The difference between the maximum X value taken by the profile of the blank A at the Y value of the blank A and the minimum X value taken by the profile of the blank A, and the maximum internal transverse distance dAA is calculated, which is defined as all dA i The maximum value in A.
[0037] -For each vertex B i Calculate distance in dB i B, the distance in dB i B is defined as the vertex B i The difference between the maximum X value taken by the profile of blank B and the minimum X value taken by the profile of blank B at the Y value of and the maximum internal lateral distance dBB is calculated, which is defined as all dB i The maximum value in B.
[0038] For example, Figure 2A In the simple case of 2 A and dA 4 A is equal to 0, and dA 3 A and dA 1 A has the same value, so dAA = dA 3 A=dA 1 A.
[0039] For the sake of clarity, Figure 2A The blank A and Figure 2B The blank B is a simple shape, but in more complex shapes, such as Figure 4 In the case of the blank U depicted in FIG. 1 , the following situations may exist: For example, in U 1 and U 2 In this case, a straight line parallel to the X axis will cross the contour multiple times. Figure 4 As depicted, 1 U and dU 2 The line segment corresponding to U can pass through the blank contour to extend from the leftmost point of the contour to the rightmost point. To illustrate another possible configuration, in dU 5 U, the line segment does not make vertex U 5 As one of its endpoints, because U 5 Located between the leftmost and rightmost points of the contour at its Y value.
[0040] The longitudinal offsets dAB and dBA are then calculated by applying the following method:
[0041] - for each vertex A at a Y value present at at least one point of the contour of the blank B i Calculate the directional distance dA i B and dBA i , directional distance dA i B and dBA i are defined as i The difference between the maximum X value taken by the contour of blank B and the minimum X value taken by the contour of blank A at the Y value of i The difference between the maximum X value taken by the profile of blank A and the minimum X value taken by the profile of blank B at the Y value of .
[0042] - for each vertex B at a Y value present at at least one point of the contour of the blank A i Calculate the directional distance dAB i and dB i A, directional distance dAB i and dB i A is defined as the vertex B i The difference between the maximum X value taken by the contour of blank B and the minimum X value taken by the contour of blank A at the Y value of the blank B, and the difference between the maximum X value taken by the contour of blank A at the Y value of the blank B i The difference between the maximum X value taken by the profile of blank A and the minimum X value taken by the profile of blank B at the Y value of .
[0043] - Calculations are limited to all dA i B and dB i The directional distance dB is the maximum value among the values, and the calculation is limited to all dB i A and dBA i The directional distance dBA is the maximum value among the values.
[0044] In e.g. Figure 3A In the case of dB, dB represents the value dA i B and dB i The corresponding orientation vector, dAB will be equal to dAB 2 .
[0045] exist Figure 3B In the case of dBA, it indicates the value of dB i A and dBA i The corresponding directional vector, dBA will be equal to dBA 3 .
[0046] After dAA, dBB, dAB and dBA have been calculated, the following method allows the calculation of Δ 1 and Δ2 :
[0047] -Δ 1 = dBA,
[0048] - If dAB + dBA ≥ dAA and dAB + dBA ≥ dBB, then Δ 2 = dBA,
[0049] - If dAB + dBA < dAA and dAA ≥ dBB, then Δ 2 = dAA - dBA,
[0050] - If dAB + dBA < dBB and dBB > dAA then Δ 2 = dBB – dBA.
[0051] Given Δ 1 and Δ 2 , the blanks A and B can now be positioned in the strip 1 by the following method: Position the first blank A in the strip; position the first blank B with a vertical offset dy and a longitudinal offset Δ 1 compared to the first blank A; position the next blank A laterally aligned with the first blank A and having a longitudinal offset Δ 2 close to the first blank B; and repeat the pattern along the longitudinal extent of the strip 1.
[0052] The inventors have found that this method allows the optimal arrangement of blanks A and B to be effectively automated.
[0053] Figure 5A , Fig. 6A and Fig. 7A are examples of determining dAA, dBB, dAB, and dBA on more complex shapes. In each figure, how to determine dBB (only the maximum dB i B is depicted for clarity) is shown in the upper left, how to determine dAA is shown in the lower left, how to determine dAB and dBA is shown in the upper right, and the table in the lower right summarizes the values of dAA, dBB, dAB, and dBA and their corresponding individual dA i A, dB i B, dA i B / dAB i , dB i A / dBA i . For example, in the Fig. 6A configuration, dAB is negative because all individual dA i B / dAB iare all negative (there are no points of profile A to the left of profile B in the range of Y values for the interaction between the superimposed blanks A and B). In this case, dAB is actually the sum of all the individual dA i B / dAB i The dA with the smallest absolute value among i B / dAB i , which would correspond to a maximum dA i B / dAB i The table at the bottom right summarizes all dAA, dBB, dBA and dBA values and details the steps for determining the spacing Δ 1 and spacing Δ 2 The calculation steps.
[0054] Figure 6C, Figure 7C and Figure 8 C plots the spacing Δ calculated previously. 1 and spacing Δ 2 The present invention provides an implementation method of the computer positioning method.
[0055] Know Δ 1 and Δ 2 , the scrap rate %Scrap can be automatically calculated using the following formula:
[0056]
[0057] In order to calculate the blank cost Cost_blank for A and B - which is defined as the material cost of blanks A and B taking into account the cost of the material, the scrap rate and the scrap cost in the case of a scrap buy-back market - the following further information is required:
[0058] the strip thickness t, which is defined above as the distance between the top side and the bottom side of the strip, t being expressed, for example, in mm,
[0059] the material cost for one unit of mass Cost_material, which is expressed, for example, in currency / ton,
[0060] In cases where the scrap material can be bought back, as is the case for example in the steel industry where the scrap is remelted, the scrap cost per unit mass Cost_Scrap, expressed for example in currency / tonne,
[0061] Material density ρ, which is defined as the ratio of the mass of a material to its volume. ρ is usually expressed in kg / m 3 express.
[0062] Cost_blank can be automatically calculated using the following formula:
[0063] M_Section=ρ*t*W*(△1 +△ 2 )
[0064] Cost_blank=Cost_material*M_Section-Cost_scrap*%Scrap*M_Section
[0065] In a particular embodiment, the material cost Cost_material depends on the width of the strip W and is actually provided in the form of a database Cost_database, which includes a set of n elements (Width_range i ,Cost_material i ), n is an integer equal to or greater than 2, and i is included between 1 and n, wherein Width_rangei is a width range having a minimum strip width value and a maximum strip width value, and Cost_material i When the strip width W is included in Width_range i The material cost per unit mass.
[0066] When the industrial cost of producing the strip does depend on the width, variable costs according to the strip width may occur. For example, if the increase in width is associated with a lower productivity, the industrial cost may increase with the width. For example, if large-width material can only be produced in certain industrial facilities, the material cost may increase with the width, resulting in higher logistics costs.
[0067] In a particular embodiment, the width W of the coil takes into account a width tolerance W_tol, usually expressed in mm. This then affects the width value W used when calculating the scrap costs and the blanking costs. The width tolerance corresponds, for example, to the accuracy that can be achieved in the strip production line in terms of width. In order to ensure that blanks A and B will fit into the strip, even when the width of the manufactured strip is at the lower end of the width tolerance range, it will be necessary to achieve a strip width W to which the width tolerance W_tol is added, which at least corresponds to the minimum width required to fit blanks A and B in the strip. Figure 8 Such a configuration is illustrated in FIG, wherein a surplus of W_tol / 2 is left on both sides of the strip 1 .
[0068] In a particular embodiment, a blanking tolerance Blank_tol, usually expressed in mm, is taken into account when positioning blanks A and B in the strip, and therefore also when calculating the scrap rate and the blank cost. The blanking tolerance corresponds to the precision of the tool used to cut the blanks out of the strip. In order to ensure that there is no overlap between the blanks when they are cut from the strip, the distance between two adjacent blanks should not be less than 2*Blank_tol (in fact, each blank is cut with the precision of Blank_tool, and the risk of overlap can only be completely avoided by providing a distance between two adjacent blanks taking into account the blanking tolerance of each individual blank). This is also Figure 8 The diagram is shown in .
[0069] In e.g. Fig. 9 In the particular embodiment shown, by first geometrically expanding blanks A and B by a factor of Blank_tol before applying the blank positioning method, the Δ 1 and Δ 2 The calculation method and the related method for determining blank positioning, scrap rate and blank cost take into account the blanking tolerance. It should be noted that although in the calculation of Δ 1 and Δ 2 The expanded blank profiles of A and B are taken into account when calculating the scrap rate %Scrap, but when calculating the scrap rate %Scrap, Area_A and Area_B in the formula are the areas of the unexpanded blank profile. In fact, the material usage in the strip is still a direct function of the areas Area_A and Area_B, not the expanded blank profile area.
[0070] In e.g. FIG. 5A to FIG. 5B , FIG. 6A to FIG. 6B and FIG. 7A to FIG. 7B In the particular embodiment depicted, the method described above is applied to a configuration in which, after rotating blank B about an axis perpendicular to the top surface of the strip, blank B has exactly the same profile as blank A. This is a very common situation in which only one blank shape is actually cut from the strip 1.
[0071] In a specific embodiment, the method described above is applied to a configuration in which, after rotating blank B about an axis perpendicular to the top surface of the strip, blank B is a mirror image profile of blank A. This is a very common situation, for example in the automotive industry, where many parts exist on both sides of a vehicle as right-hand and left-hand parts, which parts are often mirror images of each other.
Claims
1. A computer-implemented method for positioning blank A and blank B in a flat strip (1), the flat strip (1) having a rectangular shape and extending substantially along a longitudinal direction L and having a finite width extending along a transverse direction T, the lowest point of blank B being offset by an offset dy in the transverse direction compared to the lowest point of blank A, the method comprising the following steps: - Providing an X, Y coordinate system parallel to L, T, wherein blank A is positioned in the X, Y coordinate system such that the leftmost point of blank A is at X = 0 and the lowest point of blank A is at Y = 0, and blank B is positioned such that the leftmost point of blank B is at X = 0 and the lowest point of blank B is at Y = dy, - providing a numerical representation of the contour of blank A and the contour of blank B in the X, Y coordinate system, the numerical representation consisting of a set of discrete vertices {A1, ..., A P } and {B1, ..., B q }, p and q are integers greater than or equal to 3, the vertices are connected by straight edges, -For each vertex A i Calculate the distance dA i A, the distance dA i A is defined as the vertex A i The difference between the maximum X value taken by the profile of the blank A at the Y value of the blank A and the minimum X value taken by the profile of the blank A, and the maximum internal transverse distance dAA is calculated, which is defined as all dA i The maximum value in A, -For each vertex B i Calculate distance in dB i B, the distance in dB i B is defined as the vertex B i The difference between the maximum X value taken by the profile of the blank B and the minimum X value taken by the profile of the blank B at the Y value of the blank B is calculated, and the maximum internal transverse distance dBB is calculated, and the maximum internal transverse distance dBB is defined as all dB i The maximum value in B, - for each vertex A at a Y value present at at least one point of the contour of the blank B i Calculate the directional distance dA i B and dBA i , the directional distance dA i B and dBA i are defined as the vertex A i The difference between the maximum X value taken by the contour of the blank B and the minimum X value taken by the contour of the blank A at the Y value and the ... A and the minimum X value taken by the contour of the blank A at the Y value and the difference between the maximum X value taken by the contour of the blank B and the minimum X value taken by the contour of the blank A i The difference between the maximum X value taken by the contour of the blank A and the minimum X value taken by the contour of the blank B at the Y value of - for each vertex B at the Y value present at at least one point of the contour of the blank A i Calculate the directional distance dAB i and dB i A, the directional distance dAB i and dB i A is defined as the vertex B i The difference between the maximum X value taken by the contour of the blank B and the minimum X value taken by the contour of the blank A at the Y value and the ... A and the minimum X value taken by the contour of the blank A at the Y value and the difference between the maximum X value taken by the contour of the blank B and the minimum X value taken by the contour of the blank A i The difference between the maximum X value taken by the contour of the blank A and the minimum X value taken by the contour of the blank B at the Y value of - Calculate the directional distance dAB, which is defined as the distance for all dA i B and dAB i The maximum value among the values and the directional distance dBA is calculated, which is defined as all dB i A and dBA i The maximum value among the values, - Defining the spacing in the longitudinal direction between the left end of blank A and the left end of the adjacent blank B on the right side of blank A as Δ1, and setting Δ1 to the value dBA, - Defining the spacing between the left end of blank B and the left end of the adjacent blank A on the right side of blank B as Δ2, and if dAB + dBA ≥ dAA and dAB + dBA ≥ dBB, setting Δ2 to dBA, if dAB + dBA < dAA and dAA ≥ dBB, setting Δ2 to dAA - dBA, if dAB + dBA < dBB and dBB > dAA, setting Δ2 to dBB – dBA, - Positioning the first blank A in the strip, positioning the first blank B with a transverse offset dy and a longitudinal offset Δ1 compared to the first blank A, positioning the next blank A with a transverse alignment with the first blank A and a longitudinal offset Δ2 close to the first blank B, and repeating the pattern along the longitudinal extent of the strip (1).
2. The method according to claim 1, further comprising an initial step of providing a blanking tolerance Blank_tol, and the method further comprising, as a first step: geometrically expanding blank A and blank B by a factor of Blank_tol and then applying the method of claim 1 to the resulting expanded blank profiles of blank A and blank B. After rotating blank B about an axis perpendicular to the top surface of the strip (1), blank B has exactly the same profile as blank A.
3. The method according to claim 1 or 2, wherein: After rotating blank B about an axis perpendicular to the top surface of the strip, blank B has a mirror image profile of blank A.
4. The method according to claim 1 or 2, wherein: Blank A and blank B have surface areas Area_A and Area_B respectively, wherein the strip (1) extends in the transverse direction by a width W, and Δ1 and Δ2 are the spacings calculated according to any one of claims 1 to 4, and %Scrap is calculated according to the following formula:
5. A method for computerized calculation of the scrap rate %Scrap, the scrap rate %Scrap being defined as the ratio between the scrap generated by the blanking process of cutting blanks A and B from a strip (1) and the total amount of strip material used, wherein: t is the strip thickness, which is defined as the distance between the top side and the bottom side of the strip (1), Cost_material is the cost of the material per unit mass, Cost_Scrap is the cost of the scrap per unit mass, ρ is the material density, which is defined as the ratio of the mass of the material to its volume, and Cost_blank is calculated using the following formula:
6. A method for computerized calculation of a blank cost Cost_blank, the blank cost Cost_blank being defined as the material cost of blank A and blank B taking into account the cost of the material from which the strip is made, the scrap rate and the scrap cost, wherein: M_Section=ρ*t*W*(△+Δ2) Cost_blank=Cost_material*M_Section-Cost_scrap*%Scrap*M_Section.
7. Method for computerized calculation of blank costs Cost_blank according to claim 6, taking into account variable material costs Cost_material per unit mass as a function of the width of the strip, wherein Cost_material is provided in the form of a database Cost_database, which includes a set of n elements (Width_rangei, Cost_materiali), n is an integer equal to or greater than 2, and i is included between 1 and n, wherein Width_rangei is a width range with a minimum strip width value and a maximum strip width value, and Cost_materiali is the material cost per unit mass when the width W of the strip is included in Width_rangei.
8. A computer program comprising instructions which, when said program is executed by a computer, cause said computer to carry out the method according to any one of claims 1 to 7.
9. A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 7.