Cutting system with improved use of residual parts

Abstract

The system is intended to substantially sequentially handle a multiplicity of different cutting jobs at irregular times. First, a processing part is selected from the material store database. The product pieces to be produced in the current cutting job are then arranged on the processing part in an optimized manner, with the result that the processing part is divided into a coherent area comprising product pieces and a coherent residual part without product pieces. Next, a material flow control command is produced for the residual part, the material flow control command being able to assume at least a first state, which signals storage, and a second state, which signals recycling. The material flow control command is based on a reuse forecast pertaining to the residual part for a defined future period from the time of the current cutting job. This takes account of the cutting jobs performed. If the reuse forecast is above a threshold, the residual part is taken to the material store.

Description

[0001] Title:

[0002] Cutting system with improved utilization of residual parts

[0003] Description:

[0004] Technical field The invention relates to a system which has a cutting machine and a material storage and which is suitable for processing a plurality of different cutting orders which occur at irregular times essentially sequentially.

[0005] State of the art

[0006] The most economical use of raw materials in production processes is becoming increasingly important. For example, leftover raw materials that arise during production are recycled. For example, metal parts are melted down and formed into new raw material parts. It is better if the leftovers are reused within the production facility itself to manufacture other useful parts.

[0007] US Pat. No. 4,534,002 (Ltv Steel) describes a process for manufacturing pipes. Offcuts are minimized by varying the pipe lengths within the length tolerances permitted by the buyer so that no offcuts are produced, or at least the shortest possible ones. BE 1 027 915 A1 (Luckx) describes a process for manufacturing window frames from profiles, in which all offcuts with a minimum length of, for example, 50 cm are stored. Shorter profile offcuts are recycled or disposed of.

[0008] There is a need to improve material utilization even when cutting useful parts from sheet material. Currently, the decision whether or not to store a leftover part is primarily based on the individual experience of the technical specialist responsible for operating the cutting machine. Experience has shown that this leads to the material storage area becoming increasingly filled with leftover parts, which requires periodic clearing. This means that all the leftover parts are disposed of or recycled during clearing. Thus, ultimately, they are not reused in the plant—contrary to the intention at the time of storage.

[0009] Although the aforementioned processes employ a computer-aided technical method to systematically and automatically increase material utilization, they cannot be applied, or at least not satisfactorily, to the processing of sheet material.

[0010] Description of the invention

[0011] Task

[0012] The object of the invention is to create a system belonging to the technical field mentioned at the outset, which achieves an improved use of the raw material even with computers of low computing power.

[0013] Solution

[0014] The solution to the problem is defined by the features of claim 1. According to the invention, the system has at least the following components: a) a cutting machine for cutting useful parts from a standard material part or a reusable remnant part; b) a material store with standard material parts and reusable remnant parts; c) a computer; d) databases, namely i. an order database with data from cutting orders carried out in the past, ii. a material store database with data on standard parts and remnant parts, iii. an order class database with data on classes of cutting orders, iv. a remnant part class database with data on classes of remnant parts;

[0015] The system is designed to process a large number of different cutting orders that occur at irregular intervals, essentially sequentially. In practice, it is a requirement for such systems that all customer orders are processed as promptly as possible from the time of order receipt.

[0016] A current cutting order contains at least one useful part to be produced with geometric shape, material properties and number of useful parts as technical useful part data.

[0017] According to the invention, the computer is configured to carry out at least the following steps during operation for a current cutting order: e) selecting a processing part from the material storage database by i. either selecting a reusable residual part as the processing part, so that at least one useful part of the current cutting order can be produced from the residual part, ii.or a standard part is selected as the processing part if no reusable remaining part is available for the current cutting job; f) Optimized arrangement of at least some of the useful parts to be produced for the current cutting job on the processing part, so that the processing part is divided into a contiguous area with useful parts and a contiguous remaining part without useful parts; g) Generation of a material flow control command for the remaining part, whereby the material flow control command can assume at least two states for controlling a material flow, namely a state that signals storage and a state that signals recycling; h) whereby the following steps are carried out for a defined future period from the time of the current cutting job: i. Classification of the cutting jobs carried out in the past into predetermined job classes of the job class database; ii.Classifying the remaining parts from the material storage database into predefined remaining part classes in the remaining part class database; iii. Calculating a reuse forecast as of the end of the future period for the remaining part using the data from the order database and the order class database as well as the data from the material storage database and the remaining class database; iv. Comparing the reuse forecast with a lower limit; v. Generating the "store" state if the reuse forecast is at least as high as the lower limit, or generating the "recycle" state if the reuse forecast is below the lower limit; vi. Updating the material storage database if the material flow control command for the remaining part has the "store" state; vii. Inserting the current cutting order into the order database.Next, the processing part selected by the computer in step e) "Selecting a processing part" is brought from the material storage to the cutting machine. The cutting machine cuts the usable parts from the processing part. The remaining part is either stored in the material storage (for later reuse) or recycled (and thus removed from the plant) according to the material flow control command.

[0018] Advantages

[0019] Because the completed cutting jobs are divided into classes, the computational effort can be reduced significantly. For example, if 100,000 cutting jobs are divided into 500 job classes, the computational effort required to compare the calculated remaining parts with the completed cutting jobs is reduced accordingly. The comparison only needs to be made at the class level.

[0020] Classifying previously executed cutting jobs into predefined job classes can be done at times when the computer is less busy. Continuously updating the databases with a newly executed cutting job does not require a significant amount of computing power.

[0021] Because the system works with an automated decision, it creates a system that cannot be achieved with an individual decision by a specialist.

[0022] Because the system takes past cutting jobs into account when controlling the material flow, the material flow of the leftover parts is controlled dynamically. This is in contrast to the system according to BE 1 027 915 A1 (Luckx), which uses a rigid geometric criterion (e.g., minimum length of the leftover part) to optimize material utilization. The improvement in material utilization sought by the invention thus adapts to the actual material requirements. It has been shown that the proportion of recycled material can be significantly reduced with the invention. By defining a future period (which defines a time window from the current point in time) and by relating the reuse forecast to this future period, the material flow of the leftover parts through the material storage can be increased.Primarily, leftover parts are stored that will be reused within the future period and thus removed from the material warehouse.

[0023] In the system according to the invention, the material warehouse is not filled with leftover parts that are then not used. From an economic perspective, this has the advantage of comparatively reducing storage costs.

[0024] The system according to the invention is particularly suitable for processing sheet material and sheet parts. However, it is also possible to use the system for other types of parts, e.g., for cutting bar stock or pipe material. Processing of bulk materials such as plastic blocks, wood blocks, or similar is also conceivable.

[0025] In the following, particular embodiments of the invention are presented

[0026] Execution type 1: Fewer residual part classes than order classes

[0027] According to a particular embodiment of the invention, the number of residual part classes is smaller, in particular at least ten times smaller, than the number of job classes. This has the advantage of allowing a relatively fine division of the executed cutting jobs, while still keeping the computational effort required to determine the material flow control command relatively low.

[0028] Version 2: optical detection device

[0029] According to a particular embodiment of the invention, the system comprises an optical capture device that is connected to the computer for data processing. After the useful parts have been cut from the processed part, it captures an image of the cut processed part and transmits it to the computer. The computer verifies the calculated remaining part using the image and, if necessary, corrects the shape of the calculated remaining part in the material storage database. This has the advantage that the cuts on the cutting machine can be adjusted as needed, and that the data on the remaining part stored in the material storage database can be corrected according to the actual remaining part. This is important for semi-automated systems where the cutting machine operator controls certain steps manually.

[0030] In contrast to the above-mentioned design, an optical detection device can be omitted. For example, if manual intervention is not necessary or possible in the normal production process.

[0031] Execution type 3: specified past period

[0032] According to a particular embodiment of the invention, the computer is configured so that when calculating a reuse forecast at the end of the future period for the remaining part, only data from the order database that lie within a predetermined past period are taken into account.

[0033] In certain embodiments, the past period is chosen to be approximately the same size as the future period. It can also be twice as large as the future period. In both cases, the past period is of the same order of magnitude as the future period.

[0034] In further embodiments, the past period is chosen to be an order of magnitude larger than the future period. In this sense, the past period can be, for example, ten or twenty times larger than the future period.

[0035] Unlike the above-mentioned implementation, the historical period is not fixed. This is the case, for example, if the historical time is a fixed date, and thus all completed cutting jobs from the fixed date up to the current time are taken into account. As the service life of the system progresses, the historical period becomes increasingly longer.

[0036] Embodiment 4: Material warehouse full. According to a special embodiment of the invention, the material flow control command is set to recycle if the material warehouse for the leftover parts is full. This automatically ensures that no leftover part is transported to the material warehouse that cannot be stored there.

[0037] In contrast to the above-mentioned design, a separate system can also be used to ensure that the material storage area is not overfilled.

[0038] Execution type 5: Lower limits different

[0039] According to a special embodiment of the invention, not all lower limits are the same size: for offcuts or offcut classes with, for example, different material properties (stainless steel vs. brass, matte vs. glossy surface, etc.), different lower limits are available for determining the material flow control command. Different lower limits can also be set for different offcut sizes. This makes it possible to influence the material flow, for example, manually. If a lower limit is deliberately raised in the computer, fewer offcuts of the corresponding offcut class tend to be returned to the material store.

[0040] In deviation from the above-mentioned embodiment, the same lower limit can be applied to all residual part classes.

[0041] The lower limit should be set so that the probability is high, e.g., 80%, that the remaining part will be reused within the future period. It is then very likely that the remaining part will have been removed from the warehouse after three times the future period.

[0042] Execution type 6: Divide the machining part into two

[0043] According to a special embodiment of the invention, the processing part is divided into two parts in the cutting machine, namely into a continuous section with usable parts and a continuous remaining section without usable parts. When the usable parts are removed from the section with the usable parts, a so-called residual skeleton results. If the residual skeleton is separated from the unused area of ​​the processing part with a single cut during the cutting of the usable parts, this simplifies the storage of the trimmed remaining part in the material storage area.

[0044] In contrast to the above-mentioned embodiment, the remaining part is left as it is after the useful parts have been removed.

[0045] Inventive method

[0046] The invention also solves the problem of providing a method for operating a system with a cutting machine, which makes improved use of the raw material possible even with computers of low computing power.

[0047] The process should be suitable for processing a large number of different cutting jobs that occur at irregular times, essentially sequentially,

[0048] The solution to the problem is defined by a method with the following features. The method is designed to operate a system with the following components: a) a cutting machine for cutting useful parts from a standard material part or a reusable offcut; b) a material warehouse with standard material parts and reusable offcuts; c) a computer; d) databases, namely i. an order database with data from cutting orders executed in the past, ii. a material warehouse database with data on standard parts and offcuts, iii. an order class database with data on classes of cutting orders, iv.a residual part class database with data on classes of residual parts, wherein at least the following steps are carried out by a computer, in particular to improve material utilization, for a current cutting order which contains at least one useful part to be produced with geometric shape, material properties and number of useful parts as technical useful part data: e) selecting a processing part from the material storage database by i. either selecting a reusable residual part as the processing part, so that at least one useful part of the current cutting order can be produced from the residual part; ii.or a standard part is selected as the processing part if no reusable remaining part is available for the current cutting job; f) Optimized arrangement of at least some of the useful parts to be produced for the current cutting job on the processing part, so that the processing part is geometrically divided into a contiguous area with useful parts and a contiguous remaining part without useful parts; g) Generation of a material flow control command for the remaining part, wherein the material flow control command has at least two states for controlling a material flow, namely storage and recycling, wherein the following steps are carried out for a defined future period from the time of the current cutting job: i. Classification of the cutting jobs carried out in the past into predetermined job classes of the job class database; ii.Classifying the remaining parts in the material storage database into predefined remaining part classes in the remaining part class database; iii. Calculating a reuse forecast as of the end of the future period for the remaining part using the data from the order database and the order class database as well as the data from the material storage database and the remaining class database; iv. Comparing the reuse forecast with a lower limit; v. Creating the “store” state if the reuse forecast is at least as large as the lower limit, or creating the “recycle” state if the reuse forecast is below the lower limit; vi. Updating the material storage database if the material flow control command for the remaining part has the “store” state; vii. Inserting the current cutting order into the order database;

[0049] A computer program product according to the invention comprises instructions which, when the program is executed by a computer, cause the computer to carry out steps e) to g) according to the above-mentioned method.

[0050] In a special design, the machined part selected by the computer is brought from the material storage to the cutting machine. The cutting machine cuts the usable parts from the machined part, and the remaining part is either stored in the material storage or recycled according to the material flow control command.

[0051] Further advantageous embodiments and combinations of features of the invention emerge from the following detailed description and the entirety of the patent claims.

[0052] Short description of the drawings

[0053] The drawings used to explain the embodiments show:

[0054] Fig. 1 A schematic representation of a system; Fig. 2 A schematic representation of the material flow control;

[0055] Fig. 3 An example of an optimized arrangement of the useful parts on a

[0056] processing part;

[0057] Fig. 4 A schematic representation of the temporal distribution of executed

[0058] cutting orders;

[0059] Fig. 5 A schematic representation of different order classes;

[0060] Fig. 6 A schematic representation of filling the order classes;

[0061] Fig. 7 A schematic representation of different residual part classes;

[0062] Fig. 8 A schematic representation of a temporal change in the filling of the residual part classes;

[0063] Fig. 9 An example of a method for determining the material flow

[0064] control command;

[0065] Fig. 10 An example of a method for determining the material flow control command based on a trend forecast model.

[0066] In principle, identical parts in the figures are provided with identical reference symbols.

[0067] Ways to implement the invention

[0068] Fig. 1 shows a schematic representation of a system suitable for carrying out the method according to the invention. Systems of this type are used by companies that cut parts on a contract basis (so-called "job shops").

[0069] The system shown here, in a special embodiment, has the following components: A material storage 1, which, for example, has racks for storing standard panels of various sizes and thicknesses (as standard parts) and offcut panels (as offcuts). Material storage 1 is normally partially filled during operation.

[0070] • A cutting machine 2 which cuts the useful parts in the desired number and shape from a processing plate 15.

[0071] • A computer 3, which is connected to the cutting machine 2 via a data connection 4 (e.g. a WLAN) in order to transfer the cutting data for cutting the useful parts from the processing plate.

[0072] • One or more transporters 5.1, 5.2. Two transporters in the form of forklifts are shown schematically here. Their number depends on the size and requirements of the system. Transporters 5.1, 5.2 can be equipped for manual operation. However, they can also be autonomous transporters controlled by a transport system controller connected to computer 3.

[0073] • Two databases, namely an order database 6 and a material storage database 7. Order database 6 stores the cutting orders executed in the past. Currently pending but not yet processed cutting orders can also be stored, which, after their execution, are assigned to the data area of ​​the cutting orders executed in the past. Material storage database 7 stores the data of the standard panels and offcut panels available in material storage 1. Computer 3 is connected to both databases 6 and 7.

[0074] • Two additional databases, namely an order class database 17 and a remainder part class database 18. In the order class database 17, the cutting orders processed in a defined past period (calculated from the current point in time) are classified into predefined order classes. The orders in the order class are characterized at least by their processing date and the number of usable parts. An order class thus contains a series of points in time with assigned geometric usable part shapes and material properties. In the remainder part database 18, the remainder parts stored in material storage 1 in a defined past period (calculated from the current point in time) are classified into predefined order classes. The remainder parts in the remainder part classes are characterized at least by their storage time, their effective geometric shape and their material properties.A residual part class thus contains a series of points in time and the corresponding residual parts. The number of residual parts in a residual part class is also recorded.

[0075] • An output device 11 for the material flow control command. The output device 11 can be, for example, a screen for the technical operator of the cutting machine 2. The computer 3, which generates the material flow control command, is connected to the output device 11. Instead of an output device, however, an interface to the cutting machine or to a transport system controller can also be present.

[0076] • A useful part container 8: In the present example, the system has one or more useful part containers 8, in which the useful parts 13 coming from the cutting machine 2 are placed for subsequent delivery processing.

[0077] • A residual parts container 9: In this container the residual parts 13 coming from the cutting machine 2 are placed and returned to the material storage 1.

[0078] • A recycling parts container 10: This container is used to place the leftover parts that are not reused in the current plant and are therefore returned to an external material recycling facility.

[0079] • An image camera 12: According to the special embodiment 2, the present system also has an image camera 11 for checking the remaining part 14.

[0080] • An output device 16: This displays the material storage removal command from computer 3 for a cutting job.

[0081] The following material flow control methods are implemented on this system. It should be noted that not all of the above-mentioned components are mandatory for the invention. In particular, output devices can be omitted if the material flow control command or the material storage removal command is transferred directly to a transport system controller that controls the automated loading and unloading of the cutting machine or the material storage. The order class database and the remaining part database are also not mandatory for specific embodiments of the invention.

[0082] The basic material flow is now briefly explained using Fig. 1:

[0083] 1. A processing plate 15 is removed from material storage 1. This is a standard plate or a remnant plate, depending on what is displayed on the output device 16. The displayed material storage removal command is generated by computer 3. The material storage removal command is read and executed, for example, by an operator. In an automated material storage system, a transport system controller causes the transport system to implement the material storage removal command by removing the required standard plate or remnant plate.

[0084] 2. The processing plate 15 is brought to the cutting machine 2 by the transporter 5.1.

[0085] 3. The cutting machine 3 (e.g. a laser cutting machine) cuts the useful parts 13 from the processing plate 15 according to the cutting data generated by the computer 3.

[0086] 4. According to the special embodiment 2, the cut processing part is captured with the image camera 12. This can be done on the cutting table of the cutting machine or before or when the remaining part 14 is placed in the remaining part container 9.

[0087] 5. When unloading the cutting machine 3, the useful parts 13 are placed in the useful parts container 8 and the remaining part 14 is placed either in the remaining parts container 9 or in the recycling container 10. (In practice, the useful parts are often not yet completely cut out, so that the cut processing plate can first be simply removed from the cutting machine together with the useful parts. The breaking out of the useful parts only takes place as an additional step after the cut processing plate has been removed from the cutting machine 3.) Whether the remaining part 14 is recycled or reused depends on the material flow control command that the computer 3 determines and displays on the output device 11. When the cutting machine is unloaded manually, the operator reads the material flow control command on the output device 11 and executes it.In an automated system, unloading is carried out by a transport system that is activated according to the material flow control command.

[0088] 6. The transporter 5.2 brings the remnant container 10 to the material storage area 1, where the remnants are placed in the appropriate storage compartments. The output device 16 can indicate which storage compartments the remnants brought by the transporter 5.2 should be stored in. The warehouse operator sorts the remnants according to the displayed specifications.

[0089] 7. The non-reusable remaining parts in the recycling parts container 10 are removed from the plant.

[0090] As can be seen, some of the material is reused. It is crucial that not every leftover part is reused, because otherwise the material storage area would quickly become overfilled. The decision as to which leftover parts are reused is dynamic, not static, within the scope of the invention. This means that a constant criterion is not applied, as would be the case if, for example, leftover parts were less than 20 x 20 cm. 2 would always be recycled and all larger parts would always be reused. Rather, for each cutting order, a new calculation is made as to whether the resulting leftover part should be returned to the material warehouse or not.

[0091] Within the scope of the invention, it is calculated for each remaining part and with reference to the current point in time whether it will be reused within a given future period with a sufficient forecast.

[0092] Fig. 2 illustrates the steps for material flow control in the system and the structure of the required data. Step A: Record the current cutting order: The computer 3 retrieves the current cutting order 20 from the order database 6. The cutting order 20 contains at least the following parameters: a) Technical material properties: Material type (e.g., stainless steel, brass, silver) and surface finish (e.g., polished, brushed, coated); b) Geometric shape of the working parts: Surface contour, thickness; c) Number of working parts, in particular the number of identical working parts.

[0093] The database may contain additional data related to cutting order 20, such as the order receipt date, the agreed delivery date, and the unit cost of the material. However, this additional data is not relevant here.

[0094] Step B: Select processing part from material storage database:

[0095] (i) The computer 3 determines the minimum required panel area for the production of the working parts from the order data 20. For larger working part shapes, the minimum required panel area can be, for example, the rectangular panel area required for one working part. For small working part shapes, the computer can, for example, determine the rectangular area required for a minimum number (e.g., 10) of working parts as the minimum required panel area.

[0096] (ii) The computer 3 searches the material storage database 7 for remaining part data records 21 that have the minimum required panel area. If there are one or more matching remaining part data records 21, the computer 3 selects, for example, the oldest remaining part data record and defines it as the processing part 22. If there is no matching remaining part data record, the computer 3 selects a standard part data record and defines it as the processing part 22. A standard part is understood here to be a panel that is new and has never been processed in the plant. A standard part is purchased commercially and has the corresponding available size (standard size, for example, 2x2 m 2). Step C: Arrange working parts on processing part: The computer 3 arranges at least some of the working parts of the current cutting order 20 on the processing part 22. If not all working parts are arranged on the processing part 22 determined in the first pass, then steps B and C are repeated for the working parts not yet arranged until all working parts of the cutting order 20 are arranged on a processing part.

[0097] On the selected processing section 22, the computer 3 arranges the usable parts so that a contiguous area is occupied. This means that the distances between adjacent usable part shapes are as small as possible. This allows the processing section 22 to be divided into a used area and an unused area. The unused area can generally be covered essentially with a single rectangular shape or two contiguous rectangular shapes. The unused area is defined as the remaining part 23.

[0098] Fig. 3 illustrates the division of the processing part 22. The order data defines, for example, 18 useful parts with 4 different useful part shapes 23: For example, there are 4 squares, 6 triangles, 4 small ellipses and 4 large ellipses. In Step C, these 18 useful part shapes are optimally arranged on the surface of the processing part 22 so that the largest possible remaining part 23 remains. The processing part 22 now has a surface 26 occupied by useful part shapes 25 (also referred to as the residual grid) and an unused surface as the remaining part 23. Methods for the optimal space-saving arrangement of two-dimensional shapes on a surface are known to those skilled in the art. Within the scope of the invention, these methods are carried out with the specification that the remaining unused surface forms, for example, a rectangle or a combination of two different rectangles with a common side.

[0099] Step D: Generate material flow control command: The computer finally determines the material flow control command 24. This is displayed, for example, on the output device 11. Alternatively, it can be output to an unloading system of the cutting machine 2, which automatically implements the material flow control command. The material flow control command specifies whether the remaining part from the current cutting job should be reused and therefore brought to the material storage area (Fig. 1, remaining part container 9), or whether the remaining part should be recycled (Fig. 1, recycling part container 10).

[0100] The following examples explain how the material flow control command 24 can be calculated.

[0101] Fig. 4 illustrates the basic idea of ​​the invention. Time is represented on the X-axis. T othe current time is defined, i.e. the time at which computer 3 generates the material flow control command according to step D for a specific current cutting job (see step A). ​​The material flow control command is therefore dependent on the current time and is assigned to the current cutting job.

[0102] T v is the beginning of the past period [T v , T o ]. T z is the end of the future period [T O , T Z ],

[0103] On the ordinate are schematically shown various cutting jobs K b l<2...K9 are listed. These occur at random times. Fig. 3 shows the cutting order K as an example. 3tTi identified. For example, there was the order l<3 in the past period [T v , T o] six times. In contrast, order l<9 did not occur once in the same past period. If a residual part KA results that can only be recycled with cutting orders l<3, then, given the number of cutting orders l<3 that have been executed, it is likely that this residual part KA can be reused in the future period. If, on the other hand, the residual part KA' can only be recycled with cutting orders l<9, then, given the previously non-existent cutting orders l<9, it is unlikely that this residual part KA' can be reused in the future period.

[0104] According to a particular embodiment of the invention, the data recorded in the past (e.g. in the past period [T v , T o]) processed cutting orders are classified according to material properties and useful part shape. Fig. 5 illustrates the job classes with regard to various standard shapes. The standard shapes are simple geometric shapes such as rectangles and L-shapes of different sizes. Fig. 5 shows eight job classes AK1 - AK8. The job class AK1 (units length x width: 1x1) for the smallest standard shape represents, for example, the smallest processable shape. All cutting orders with useful parts that fit into this smallest shape are assigned to job class AK1. All cutting orders that fit into the standard shape of this job class AK2 but not into the standard shape of the next smaller job class AK1 are classified into job class AK2 with the next larger standard shape (units length x width: 2x1). In this way, all cutting orders can be classified into the predefined job classes AK1 to AK8.

[0105] The number of job classes defined per material depends on the specific case. In most applications, at least 5 and no more than 50 job classes per material property will suffice. If the number of cutting jobs exceeds 1,000 or 10,000, this approach will significantly reduce the computing power required in Step D.

[0106] Fig. 6 illustrates with a histogram a possible result of the classification of the cutting orders at a certain time T o The order classes are filled to varying degrees. With each new cutting order executed, the frequency distribution changes. According to a special embodiment of the invention, the past period is always the same length. This means that in the order class database, cutting orders that were executed before time T are deactivated or deleted. v The order class database is therefore dynamic.

[0107] The order class database is updated at regular intervals (e.g. daily).

[0108] In the sense of the above-mentioned special embodiment of the invention, the inventions made in the past (e.g. in the past period [T v , T o]) are classified according to material properties and shape. Fig. 7 illustrates the remainder part classes with regard to various standard shapes. The standard shapes are simple geometric shapes such as rectangles with different side lengths and therefore different sizes. Fig. 7 shows five remainder part classes RK1 - RK5 as examples. The remainder part class RK1 (2x2: 2 length units in width and 2 length units in length) for the smallest standard shape represents, for example, the smallest reusable shape of a remainder part. All remainder parts that have at least one such contiguous free area but do not yet meet the area requirement of the remainder part class RK2 (2x3) are assigned to the remainder part class AK1.All remnants that have at least a contiguous area of ​​2x3 but do not meet the area requirement of the next larger remnant class RK3 (5x1) are classified into the remnant class RK2 with the next larger standard shape (2x3). In this way, all remnants can be classified into the predefined remnant classes RK1 to RK5.

[0109] In general, the following applies: The largest remaining part class RK5 (size in relation to the area) is smaller than the standard shape of the raw material plates of the respective material.

[0110] In many applications, the largest remnant class (in Fig. 7: RK5) will also be larger than the largest order class (in Fig. 7: AK8). This applies in cases where the largest shapes in the cutting orders are significantly smaller than the standard shape of the raw material plates. If this condition is met, a standard plate or a remnant plate can generally be considered as the machining part for each cutting order. It may, of course, be the case that no suitable remnant plate is currently available in the material warehouse. In this case, a standard plate is used as the machining plate.

[0111] How many remainder classes are defined per material depends on the individual case. Regardless of the present exemplary embodiments, it can be stated that in most applications at least 4 and no more than 20 remainder classes per material property are sufficient. Preferably, fewer remainder classes are defined per material property than order classes. For example, there are at least five times more, in particular ten times more order classes than remainder classes. Fig. 8 uses a histogram to illustrate a possible result of the classification of the remainders at two different points in time T and T2. The remainder classes RK1, RK5 are filled to varying degrees. The frequency distribution can change with each new cutting job carried out: On the one hand, a remainder may have been taken from the material storage database and finally used up. On the other hand, a new (e.g. smaller) remainder may be returned.Or a standard material part can result in a reusable leftover part.

[0112] In the remnant class database, remnant parts are stored as long as they are available in the material warehouse.

[0113] If the system is optimally configured, the material warehouse is never completely full of leftover parts. Rather, there is a constant flow of leftover parts through the material warehouse. In particular, the material flow should be as high as possible. This demonstrates that the leftover parts stored are being utilized optimally.

[0114] Fig. 9 illustrates a first embodiment for determining the material flow control command 24 in step D of Fig. 2. The remaining part 23 is taken from the previous step C.

[0115] Step DA: Determination of the remaining part class RKi: in the remaining part class database 17, the remaining part class RKi is determined to which the calculated remaining part 23 is to be assigned.

[0116] Step DB: Determine whether the remnant class RKi is full: If the remnant class 17 is full (i.e., if the material storage area in which the remnants of this remnant class are stored is full), the material flow control command is set to "recycle" (Fig. 9: "status = 0"). This means that the remnant 23 is placed in the recycling container 10 after the cutting process.

[0117] Step DC: Determine order classes for the remaining part class RKi: Now, using the order class database 17, it is determined which order classes AKj can be accommodated in the remaining part class RKi. For example, the order classes AK1, AK2, AK3, AK5, AK6, and AK7 can be accommodated in the remaining part class RK2 as shown in Fig. 7. This means that all useful part shapes of the cutting orders contained in the determined order classes can be accommodated on the remaining part.

[0118] Step DD: Material flow in order classes: If in all order classes determined according to Step DC in the past period [T v , T o ] If no cutting orders have been added, the material flow control command 24 is set to "recycle" (Fig. 9: "status = 0"). Otherwise, the material flow control command 24 is set to "store" (Fig. 9: "status = 1"). In addition, when the status is "store," the residual part class database 18 is updated with respect to the residual class RKi.

[0119] For the embodiment described above, it is assumed that the past period considered [T v , T o ] according to Fig. 4: is essentially the same size as the future period [T o , T z ], For example, the future period is 6 months.

[0120] Fig. 10 illustrates a second embodiment for determining the material flow control command 24 in step D of Fig. 2. In this embodiment, the past period is much larger than the future period, in particular by at least a factor of ten. For example, if the future period is 6 months, then the past period is approximately 5 years.

[0121] The second embodiment is based on the cutting orders completed in the past period. From these, it is determined whether the forecast that the remaining part can be recycled by the end of the future period exceeds a selected lower limit.

[0122] Fig. 10 is based on Step DA to Step DD of Fig. 9 but does not lead directly to «status= 1 » after Step DD, but carries out the following additional steps:

[0123] Step DE: Divide the past period into time intervals: The past period [T v , T o] is divided into a predefined number l< of time intervals of length (T0-T v ) / K decomposed: Time interval k= 1 : [T v ,Tv+(T0-Tv) / K)]

[0124] Time interval k=2: [T v +(To-Tv) / K,-Tv+2(T o -Tv) / K)]

[0125] Time interval k=K: [T V +(K-1)(T O -T V ) / K), T o ]

[0126] For example, a past period of 2 years is divided into K = 12 time intervals of 2 months. For each time interval, the number N k executed cutting jobs that fall into one of the determined job classes AKj from Step DD are counted. This results in a time series N b N K (basically one measured value per time interval).

[0127] Step DF: Recycling forecast by trend determination: From the data reduced according to Step DE, the trend for the future period T is determined zFor this purpose, an estimated value N(T0+h |T0) is calculated using the following formula: where:

[0128] Step DG: Comparison of the recycling forecast with a threshold: The estimated value N(T0+h|T0) calculated in Step DF is compared with a predefined threshold S(RKi) of the residual part class RKi. If the estimated value is below the threshold, the material flow control command 24 is set to "recycle" (Fig. 10: "status = 0"). Otherwise, the material flow control command 24 is set to "store" (Fig. 10: "status = 1"). Furthermore, when the status is "store," the residual part class database 18 is updated with respect to the residual part class RKi. According to a special embodiment, not all residual part classes have the same threshold. For example, for a residual part class, the threshold can be set higher than the average of all thresholds of the residual part classes if, for example, storing the corresponding residual parts is particularly complex.

[0129] A third embodiment is that a linear trend calculation model is used in Step DF:

[0130] The parameters a, are determined using the so-called Yule-Walker equations. The autocorrelation matrix to be used is estimated from the measured values ​​N,. The parameter p is chosen to be sufficiently large.

[0131] The procedures described above can be modified so that classification is virtually omitted:

[0132] • With regard to the remainder part classes, this is essentially achieved in the above examples by defining a separate remainder part class for each possible remainder part. Only identical remainder parts are then assigned to the same remainder part class.

[0133] • With regard to job classes, this is essentially achieved in the above examples by defining a separate job class for each cutting job performed. Only identical part shapes and parts materials are then assigned to the same job class.

[0134] A further modification of the calculation of the material flow control command is that it is always set to "store" if there are a sufficient number of cutting orders executed in the past period. For example, the status "store" is set if in the past period [T V ,T O] the number of cutting jobs carried out reaches at least the threshold value S(RKi) (e.g. S(RKi) = 2). The steps according to steps DA to DD are simplified accordingly. In order to minimize the variety of shapes of the remaining parts, a rectangular shape can be specified for the unused surface area of ​​the processing part. This means that the remaining part can be defined by its length and width. Fig. 3 shows an example of this. However, it can also be advantageous if shapes are permitted that can be formed from two adjoining rectangles. This includes, in particular, L-shapes in the broadest sense. For maximum material utilization, on the other hand, it is advantageous if any contours are permitted, e.g. contours that result from the useful parts being removed from the processing plate. However, any triangular or square shape or any hexagonal shape can also be defined as the permissible shape of the remaining part.

[0135] In summary, the invention enables automated optimization of the material flow with reduced computational effort.

[0136] Reference symbol:

[0137] 1 material warehouse

[0138] 2 cutting machines

[0139] 3 computers

[0140] 4 Data connection

[0141] 5.1 , 5.2 Transporter

[0142] 6 Order database

[0143] 7 Material storage database

[0144] 8 parts containers

[0145] 9 waste containers

[0146] 10 recycling bins

[0147] 1 1 Output device

[0148] 12 Image camera

[0149] 13 useful parts

[0150] 14 Remaining part 15 Processing plate

[0151] 16 Output device

[0152] 17 Order class database

[0153] 18 Remaining part class database

[0154] 20 cutting orders

[0155] 21 Remaining part data record

[0156] 22 Processing part

[0157] 23 Remaining part

[0158] 24 Material flow control command

[0159] 25 useful part shapes

[0160] 26 Occupied area

[0161] AK1, AK8, AKj order classes

[0162] RK1, RK5, RKi remaining part classes

[0163] K1 , I<9 cutting order

[0164] KA remaining part

[0165] To Current Time

[0166] TV past time

[0167] Tz future time

Claims

Patent claims 1. A system suitable for processing a plurality of different cutting orders occurring at irregular times essentially sequentially, comprising the following components: a) a cutting machine (2) for cutting useful parts (13) from a standard material part or a reusable residual part; b) a material store (1) with standard material parts and reusable residual parts; c) a computer (3); d) databases, namely i. an order database (6) with data from cutting orders carried out in the past, ii. a material store database (7) with data from standard parts and residual parts, iii. an order class database (17) with data on classes of cutting orders, iv. a residual part class database (18) with data on classes of residual parts, wherein the computer (3), in particular for improving material utilization, for a current cutting order, which contains at least one useful part to be produced with geometric shape, material properties and number of useful parts as technical useful part data, carries out at least the following steps: e) selecting a processing part (Step B) from the material storage database by i. either selecting a reusable residual part as the processing part, so that at least one useful part of the current cutting order can be produced from the residual part; ii.or a standard part is selected as the processing part if no reusable remaining part is available for the current cutting job; f) Optimized arrangement (Step C) of at least some of the useful parts to be produced for the current cutting job on the processing part, so that the processing part is geometrically divided into a contiguous area with useful parts and a contiguous remaining part without useful parts; g) Generation of a material flow control command (Step D) for the remaining part, whereby the material flow control command can assume at least two states for controlling a material flow, namely a state which signals storage and a state which signals recycling, h) whereby the following steps are carried out for a defined future period (TZ) from the time of the current cutting job (TO): i.Classifying the cutting orders executed in the past into predefined order classes of the order class database; ii. Classifying the remaining parts in the material storage database into predefined remaining part classes of the remaining part class database; iii. Calculating a reuse forecast as of the end of the future period for the remaining part using the data from the order database and the order class database as well as the data from the material storage database and the remaining class database; iv. Comparing the reuse forecast with a lower limit; v. Generating the "store" state if the reuse forecast is at least as large as the lower limit, or generating the "recycle" state if the reuse forecast is below the lower limit; vi. Updating the material storage database if the material flow control command for the remaining part has the "store" state; vii.Inserting the current cutting order into the order database; after which, in the system, the processing part selected by the computer in step e) is brought from the material storage to the cutting machine, the cutting machine cuts the usable parts from the processing part, and the remaining part is either stored in the material storage or recycled according to the material flow control command.

2. Plant according to claim 1, characterized in that it has an optical detection device (12) which is connected to the computer (3) for data processing and which, after the useful parts (13) have been cut from the processing part, detects an image of the cut processing part, and that the computer (3) verifies the calculated remaining part on the basis of the image and corrects it if necessary.

3. System according to one of claims 1 or 2, characterized in that when calculating a reuse forecast as of the end of the future period for the remaining part, the computer only takes into account data from the order database which lie within a predetermined past period.

4. Plant according to one of claims 1 to 3, characterized in that the material flow control command is set to recycle if the material storage for the remaining parts is full.

5. Plant according to one of claims 1 to 4, characterized in that for residual parts of different material properties, different lower limits are provided for determining the material flow control command.

6. System according to one of claims 1 to 5, characterized in that during cutting the processing part is divided into two parts: a continuous area with useful parts and a continuous remaining part without useful parts.

7. A system suitable for processing a large number of different cutting orders occurring at irregular times, essentially sequentially, comprising the following components: a) a cutting machine for cutting useful parts from a standard material part or a reusable residual part; b) a material store with standard material parts and reusable residual parts; c) a computer; d) databases, namely i. an order database with data from cutting orders carried out in the past, ii. a material store database with data from standard parts and residual parts, wherein the computer, in particular for improving material utilization, for a current cutting order, which contains at least one useful part to be produced with geometric shape, material properties and number of useful parts as technical useful part data, carries out at least the following steps: e) selecting a processing part from the material storage database by i. either selecting a reusable residual part as the processing part, so that at least one useful part of the current cutting order can be produced from the residual part; ii.or a standard part is selected as the processing part if no reusable remaining part is available for the current cutting order; f) Optimized arrangement of at least some of the useful parts to be produced for the current cutting order on the processing part, so that the processing part is divided into a contiguous area with useful parts and a contiguous remaining part without useful parts; g) Generation of a material flow control command for the remaining part, whereby the material flow control command can assume at least two states for controlling a material flow, namely a state that signals storage and a state that signals recycling, h) whereby the following steps are carried out for a defined future period (TZ) from the time of the current cutting order (TO): i. Calculating a reuse forecast as of the end of the future period for the remaining part using the data from the order database; ii.Comparing the reuse forecast with a lower bound; iii. Generating the store state if the reuse forecast is at least as large as the lower bound or generating the state. recycle if the reuse forecast is below the lower limit; iv. update the material storage database if the material flow control command for the remaining part has the status "store"; v. insert the current cutting order into the order database; after which, in the system, the processing part selected by the computer in step e) is brought from the material storage to the cutting machine, the cutting machine cuts the usable parts from the processing part, and the remaining part is either stored in the material storage or recycled according to the material flow control command.

8. A method suitable for processing a large number of different cutting orders occurring at irregular times, essentially sequentially, for operating a system with the following components: a) a cutting machine for cutting useful parts from a standard material part or a reusable residual part; b) a material store with standard material parts and reusable residual parts; c) a computer; d) databases, namely i. an order database with data from cutting orders carried out in the past, ii. a material store database with data from standard parts and residual parts, iii. an order class database containing data on classes of Cutting orders, iv. a residual part class database with data on classes of residual parts, wherein at least the following steps are carried out by a computer, in particular to improve material utilization, for a current cutting order which contains at least one useful part to be produced with geometric shape, material properties and number of useful parts as technical useful part data: e) selecting a processing part from the material storage database by i. either selecting a reusable residual part as a processing part, so that at least one useful part of the current cutting order can be produced from the residual part; ii.or a standard part is selected as the processing part if no reusable residual part is available for the current cutting job; f) Optimized arrangement of at least some of the useful parts to be produced for the current cutting job on the processing part, so that the processing part is geometrically divided into a contiguous area with useful parts and a contiguous residual part without useful parts; g) Generation of a material flow control command for the residual part, wherein the material flow control command has at least two states for controlling a material flow, namely storage and recycling, wherein the following steps are carried out for a defined future period (TZ) from the time of the current cutting job (TO):. i. Classifying the cutting orders executed in the past into predefined order classes of the order class database; ii. Classifying the remaining parts in the material storage database into predefined remaining part classes of the remaining part class database; iii. Calculating a reuse forecast as of the end of the future period for the remaining part using the data from the order database and the order class database as well as the data from the material storage database and the remaining class database; iv. Comparing the reuse forecast with a lower limit; v. Generating the "store" state if the reuse forecast is at least as large as the lower limit or generating the "recycle" state if the reuse forecast is below the lower limit; vi. Updating the material storage database if the material flow control command for the remaining part has the "store" state; vii. Inserting the current cutting order into the order database; 9. Method according to claim 8, characterized in that further in the system the processing part selected by the computer is brought from the material store to the cutting machine, the cutting machine cuts the useful parts from the processing part and the remaining part is either stored in the material store or recycled according to the material flow control command.

10. A computer program product comprising instructions which, when executed by a computer, cause the computer to perform the steps of claim 8:

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