DYNAMIC PRODUCTION PLANNING METHOD FOR CONTINUOUS CASTING PLANTS

Abstract

A dynamic production planning method for a continuous casting plant for casting a strand with a production system which has a predefined production plan, which method includes comparing target production parameters with actual production parameters. If the actual production parameters deviate from the target production parameters, a strand image is created on the basis of actual production parameters. With the aid of the calculated strand image, a check is carried out within the predefined production plan and, if possible, a new production plan is created. If no solution can be found from the predefined production plan, the strand image is transmitted to a production planning system. The production planning system creates a new production plan from all available orders on the basis of a predefined optimization criterion. The new production plan is subsequently transmitted to the production system.

Claims

1. A dynamic production planning method for a continuous casting plant for casting a strand with a production system which has a predefined production plan, comprising: a comparison of setpoint production parameters with actual production parameters, if the actual production parameters deviate from the setpoint production parameters, a strand image is created on the basis of actual production parameters, wherein the strand image comprises the strand which has already been cast and has not yet been cut, and at least that strand which is obtained on the basis of a residual weight in the tundish and predefined parameters, checking, on the basis of the calculated strand image, within the predefined production plan and, if possible, creating a new production plan, if no solution can be found from the predefined production plan, the strand image is transmitted to a production planning system, the production planning system creates a new production plan from all available orders on the basis of a predefined optimization criterion, transmission of the new production plan to the production system.

2. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein the strand image is formed from at least one of the following parameters: width profile on the strand, width profile in the tundish, scrap positions and lengths, quality prediction for the strand, product limits of the calculated solution for product specification, target quality of the specified products

3. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein a unique key, preferably a hash code, is calculated on the basis of the strand image and this is used in data exchange with the production system and the production planning system.

4. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein the optimization criterion is a maximum possible sales revenue with a minimum possible storage period or a maximum possible sales revenue with the prioritization of low-priority orders.

5. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein characterized in that a connection between the production system and the production planning system is a decoupled bi-directional connection.

6. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein characterized in that the production plan is a cutting plan with a setpoint length, minimum length, maximum length, width and/or thickness.

7. The dynamic production planning method for a continuous casting plant for casting a strand as claimed in claim 1, wherein the actual production parameters and the setpoint production parameters are a casting speed of the strand, a casting level, a mold width, a strand cooling parameter, a temperature of the melt and/or a casting powder thickness.

8. A continuous casting plant comprising at least one computer system for carrying out the method as claimed in claim 1.

9. The continuous casting plant as claimed in claim 8, further comprising a first computer system for a production system and a second computer system for a production planning system, wherein the first computer system and the second computer system are connected to one another by a decoupled bi-directional connection.

10. A computer program residing on a non-transitory computer-readable medium, the computer program comprising commands which ensure that a continuous casting plant carries out the method steps as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 shows a schematic illustration of a continuous casting plant.

[0050] FIG. 2 shows a strand with associated quality information.

[0051] FIG. 3 shows an activity diagram for the method described.

DESCRIPTION OF THE EMBODIMENTS

[0052] In FIG. 1, a continuous casting plant 1 is illustrated schematically. Liquid metal 6 is poured into a mold 2 and a cast strand 7 is then drawn off from the mold 2. A production system 3 is implemented on a computer system. By means of the production system 3, which has a process and model calculation 3a and a memory system 3b, data with positions—at which a flame cutting machine 10 is to cut the strand 7—are transmitted to a programmable logic controller 5a. The production system 3 receives input parameters from the production planning system 4 and the closed-loop and open-loop electronic control system 5. The production planning system 4 is also implemented on a computer system. These input parameters can be transmitted, on the one hand, by the programmable logic controllers 5a via a data line 8 and/or by a higher-order control system of the industrial plant. The programmable logic controller 5a is connected to measuring instruments 5b and/or control elements 5c. The parameters detected by the measuring instruments 5b are, for example, the measured strand dimensions, temperature of the melt, casting speed and/or parameters of the cooling section. A composition of the melt is available to the production system 3 or can be called up from a memory 3b.

[0053] If, for example, the production system 3 detects deviations from actual values with respect to setpoint values during production, a strand image is calculated and the production system 3 attempts to reconfigure a predefined production plan in such a way as to compensate for these deviations. The actual parameters are calculated by the process and model calculation 3a. If this is not possible, the strand image is transmitted to the production planning system 4 via the decoupled bi-directional connection 9. The planning system retrieves available customer orders from the order book 4b and attempts to create a new production plan on the basis of the parameters stored in the production planning computer 4a. As soon as the new production plan has been determined, it is transmitted from the production planning system 4 to the production system 3.

[0054] FIG. 2 illustrates a strand 7 as it can occur in a running production process. Here, the casting direction is to the left from the mold position 25. The strand 7 has a cut edge 21, which forms a possible zero point. This zero point can also be further behind owing to processing times. A section that cannot be used for further production is a scrap region 22.

[0055] A width change region 23 occurs when the width settings of the mold are increased or decreased. A region which forms a changed width region 24 then occurs. A region from the cut edge 21 to the mold position 25 forms that region which has already been cast. The width change region 26 and the residual region 27 form those regions which result from a residual quantity of liquid metal in the tundish. These two regions are therefore only produced at the time of observation.

[0056] In a quality prediction 30, calculated actual qualities for individual strand sections are formed. In a target quality 31, those qualities are depicted which were originally to be generated by the predefined production plan. As can be seen from the comparison of quality prediction 30 and target quality 31, these do not coincide, as a result of which a new production plan is to be created.

[0057] FIG. 3 shows an activity diagram.

[0058] In step S1, the production plan is always updated. In the next step S2, the cutting plan is calculated on the basis of the production plan. If no deviation is found in the interrogation Q1, there follows step S10, in which the corresponding cutting lengths are specified and these are transmitted from the production system 3 (level 2 system) to a flame cutting machine. In the event of a deviation, a step S4—the creation of a strand image—is initiated in the interrogation Q1. The strand image created is checked in step S5 and, in the event of a deviation in the interrogation Q2, step S6 is initiated, which generates a request message and transmits it to a production planning system 4. The connection between the production system 3 and the production planning system 4 is advantageously effected via a decoupled bi-directional connection 9. In one advantageous embodiment, this request message contains a calculated unique key, which subsequently serves as an identification in the further data exchange between the production system 3 and the production planning system 4. This key makes it possible to determine quickly whether relevant data have changed between calculation steps. In step S7, the request message is used by the production planning system 4, and a check of the entire order book is carried out in step S7 on the basis of this request message. The finding of suitable customer orders is checked in the interrogation Q3. If this is the case, a production plan update is created in step S8 and a response message is transmitted to the production system 3. In the case that no suitable customer orders are found in the interrogation Q3, no update of the production plan is created. In this situation, the production system 3 continues to operate with the originally specified production plan, or the production system changes the production plan in accordance with other specifications.

[0059] If a production plan update has been created, it is transmitted by response message via the decoupled bi-directional connection 9 from the production planning system 4 to the production system 3. In step S9, the transmitted response message is checked at the production system 3 to determine, for example, whether the response message has the same key as the request message. In the interrogation Q4, it is then determined whether the data are valid; if this is the case, a new cutting plan is calculated in step S2. If the data in the interrogation Q4 were considered invalid, then no transmission of the data to step S2 takes place. As in the case of interrogation Q3, the original production plan is then continued or the production plan is changed on the basis of other specifications. This can be performed in such a way, for example, that scrap lengths are specified, or standard lengths are specified for certain grades, which are placed in store.

[0060] Although the invention has been illustrated and described more specifically in detail by means of the preferred illustrative embodiments, the invention is not restricted by the examples disclosed, and other variations can be derived therefrom by a person skilled in the art without exceeding the scope of protection of the invention.

LIST OF REFERENCE SIGNS

[0061] 1 continuous casting plant [0062] 2 mold [0063] 3 production system [0064] 3a process and model calculation [0065] 3b memory [0066] 4 production planning system [0067] 4a production planning calculation [0068] 4b order book [0069] 5 closed-loop and/or open-loop control system [0070] 5a programmable logic controller [0071] 5b measuring instruments [0072] 5c control elements [0073] 6 liquid metal [0074] 7 strand [0075] 8 data line [0076] 9 decoupled bi-directional connection [0077] 10 flame cutting machine [0078] 21 cut edge [0079] 22 scrap region [0080] 23 width change range [0081] 24 changed width range [0082] 25 mold position [0083] 26 width change range [0084] 27 residual region [0085] 30 quality prediction [0086] 31 target quality [0087] S1-S10 step [0088] Q1-Q4 interrogation