Method for generating decision support to determine whether to implement out-of-plan maintenance on production station

Abstract

The invention relates to a method for generating a decision support for determining whether an out-of-plan maintenance or a planned maintenance should be carried out during a production process on at least one production station (10) of a production line (100), said production station (10) being provided for producing a total number (X) per unit of time, the production station (10) has a defect rate (Q) of defective parts produced per unit of time, comprising the following steps: a) determining the remaining time (trest) until the next planned maintenance; b) determining a reject number (Xus) of defective parts until the next planned maintenance based on the total number (X), the remaining time (trest) and the defect rate (Q); c) determining a maintenance time (wart) for maintaining the production station, d) determining a number of shuts down (Xnicht) of unproduced parts during the maintenance time (wart) on the basis of the total number (X) and the maintenance time (wart), and e) comparing the number of rejects (Xaus) with the number of shuts down (Xnicht) and displaying a decision support on the basis of the comparison.

Description

Technical Field

[0001] The invention relates to a method for generating decision support for deciding whether unplanned maintenance or planned maintenance should be carried out during the production process at at least one production station of a production line. The invention also relates to a system, a computer program product and a vehicle having a vehicle component manufactured in a production line, in which a decision is made with the aid of a method for production decision support whether planned maintenance or unplanned maintenance should be carried out. Background Art

[0002] Complex production lines, such as a coating line for coating battery cells, usually include multiple production stations, in which separate and partially spatially separated production processes in the value chain for creating the final product are respectively implemented. A production station can be, for example, a value creation station for implementing a production step or a receiving station. A production line in the sense of the present invention can be constructed in such a way that it includes only one production station. A single production station is here simultaneously the entire production line. However, it is generally common for a production line (as described above) to include multiple production stations.

[0003] The production line is designed for the production of components. A "component" may be understood, for example, as a component of an individual assembly or a vehicle component consisting of a plurality of assemblies, such as a battery module. Examples of production lines are painting lines for the painting of battery cells, module lines, storage lines or production lines outside of electrification.

[0004] The production line is designed to produce a certain number of components per hour according to the theoretical overall equipment efficiency. The time unit "hour" is only an example of a commonly used time unit. Other possible time units are, for example, minutes or days.

[0005] The theoretical overall equipment effectiveness is also known as "Overall Equipment Effectiveness", abbreviated as OEE. The production line itself produces fewer parts per hour than the total number of the overall equipment effectiveness. The total number should not be less than 75% of the overall equipment effectiveness, for example. In general, the overall equipment effectiveness is reduced, for example due to the production of defective parts or increased cycle time.

[0006] Defective parts produced are parts that are produced outside the production specifications. These parts are often also referred to as "non-conforming" or abbreviated as "nO". The number of defective parts produced per time unit at a production station constitutes the scrap quantity. The scrap quantity can be given as a percentage of the total. It should be noted here that defective parts produced in a production station can also lead to defective parts produced in the production line at the same time. In particular, when multiple subsequent production steps are carried out in succession on a component in multiple production stations. The information that a part is produced defectively in a production station can be transmitted directly to the monitoring system or the operating personnel. As a result, it can be immediately displayed that a production process is out of control. "Out of control of the production process" can be understood as an increase in the number of defective parts produced at a production station, especially exceeding an acceptable value.

[0007] In order for the individual production stations of a production line to produce components according to production specifications over, for example, the entire service life of the production line, the individual production stations are regularly maintained at planned maintenance intervals. For this purpose, the planned maintenance intervals are usually timed so that they are carried out, for example, after get off work or during a rest phase when no components are produced. As a result, the planned maintenance does not affect the number of components produced during the production process.

[0008] A single production run takes place between two planned maintenance intervals. Parts are produced during this time if no unplanned maintenance is performed.

[0009] Unplanned maintenance is maintenance that has to be carried out during the production process. In this case, at least the production station to be maintained must be shut down so that the maintenance can be carried out. In most cases, the entire production line is affected, so that all production stations must interrupt the production process. Unplanned maintenance lasts for a maintenance time. During this maintenance time, no parts can be produced. As a result, the unplanned number of parts lost due to unproduced parts increases. Usually, unplanned maintenance is carried out when the error rate increases during the production process at a production station. After the unplanned maintenance is over, the production line is restarted and the production process continues until the next planned maintenance.

[0010] However, the problem here is that, particularly in the case of a large number of production stations, it is difficult to assess whether it makes sense to carry out unplanned maintenance during the production process preceding planned maintenance.

[0011] For this purpose, EP 1 959 325 A2 discloses a method for predicting the average time interval between two downtimes of a production system. The method is used primarily to predict the frequency of unplanned downtimes and the downtime duration associated therewith.

[0012] EP 2 837 984 A2 discloses a method for optimally timing planned maintenance work on a wind farm, thereby aiming to extend the availability and service life of the wind turbines.

[0013] WO 2011 1054 005 A2 discloses a method for automatically predicting planned maintenance work for a tool. For this purpose, maintenance data about the maintenance work that may occur on the tool are known. Based on this information, the maintenance of multiple tools can be scheduled in an optimal manner. Summary of the invention

[0014] The object of the present invention is to provide a method by means of which the number of components produced during a production process can be maximized.

[0015] In order to achieve this object, a method according to claim 1 , a system according to claim 8 , a computer program product according to claim 9 and a vehicle according to claim 10 are proposed.

[0016] Advantageous embodiments of the method are the technical solutions of claims 2 to 7.

[0017] A method according to the invention for generating decision support for determining whether unplanned maintenance or planned maintenance should be performed during a production process at at least one production station of a production line. The production station is arranged to produce a total number of parts per time unit and has a defect rate of defective parts produced per time unit. The method comprises the following steps:

[0018] a) determine the time remaining until the next planned maintenance;

[0019] b) determine the scrap quantity of defective parts until the next planned maintenance based on the total number, remaining time and defect rate;

[0020] c) Determine the maintenance time for maintaining the production station;

[0021] d) determine, based on the total number and maintenance time, the number of downtimes during which the part was not produced during the maintenance time; and

[0022] e) compare the scrap quantity to the downtime quantity and

[0023] f) display decision support based on the comparison.

[0024] The method according to the invention has the advantage that the operating personnel are supported if carrying out unplanned maintenance can produce more parts that meet the defined product specifications than continuing the production process with an increased defect rate until planned maintenance. Precisely because it usually takes about 20 minutes until such a decision is made, the decision is greatly simplified and thus accelerated by the proposed method, because the operating personnel can immediately decide whether to carry out unplanned maintenance.

[0025] In an advantageous embodiment, the reject quantity is determined by multiplying the total number, the remaining time and the defect rate, wherein the total number is given as parts per time unit, the remaining time is given in the same time unit and the defect rate is given as a percentage of the total number.

[0026] An operator is, for example, a foreman in charge of a production line in a factory.

[0027] In an advantageous embodiment of the method, if the number of rejects is greater than or equal to the number of downtimes, decision support is displayed indicating that unplanned maintenance should be carried out.

[0028] This allows a clear boundary to be introduced as a decision support. Thus, the question of whether to continue production with an increased defect rate or to implement an unplanned maintenance stop can be strictly monitored.

[0029] Advantageously, the duration of the maintenance time is defined by the determined fault. The duration of the maintenance time or the unplanned maintenance can vary depending on the maintenance work to be carried out. The production station to be maintained can also be a factor in defining the duration of the unplanned maintenance. Generally speaking, for this purpose, it is known in advance how long the corresponding unplanned maintenance lasts or how long the maintenance time is by statistical observation. Typically, the duration of the maintenance time is 10 minutes, 20 minutes or 60 minutes. Therefore, "determining the maintenance time" can be understood, for example, as determining a production station with an increased amount of scrap and determining the maintenance time for this production station from a database.

[0030] Advantageously, the decision support is displayed in a graphical representation. The graphical representation enables an intuitive representation in a particularly advantageous manner, so that the operator receives an indication at a glance whether an unplanned maintenance should be carried out. The graphical representation can have two axes. The time until the next maintenance is shown on the y-axis and the defect rate is shown on the x-axis.

[0031] Advantageously, the decision support displays the decision point at which the number of scrap equals the number of downtimes. The decision point enables clear assistance and presents a simple and visual decision support to the operator. In the graphical representation the decision point can be a line with a regression curve.

[0032] Advantageously, the scrap quantity includes the quantity of produced components that are outside of a defined product specification. In production stations producing, for example, different components or components for different application purposes, such as vehicle grade, the product specification may be different. Therefore, the decision whether a component is outside of the product specification may also be different. Therefore, a defined product specification allows for a detailed observation.

[0033] Advantageously, the production line comprises at least two production stations. Complex production lines have more than one production station. Monitoring and decision support are particularly advantageous here, because a large number of production stations and different maintenance times make it difficult for the operating personnel to estimate whether unplanned maintenance should be carried out based solely on their experience.

[0034] Another aspect of the invention relates to a system for data processing, comprising means for executing the steps of the above method.

[0035] Another aspect of the invention relates to a computer program product comprising instructions which, when a computer executes said program, cause the computer to perform the above method.

[0036] Another aspect of the invention relates to a vehicle having a vehicle component which is manufactured in a production line, in which a decision is made with the aid of the method for generating decision support as described above whether planned maintenance or unplanned maintenance is to be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The vehicle and the production line as well as further features and advantages are explained in detail below with reference to exemplary embodiments schematically shown in the drawings. The drawings are as follows:

[0038] Figure 1 A production line including production stations is shown;

[0039] Figure 2 showing a graphical representation for displaying a decision support according to the present invention; and

[0040] Figure 3 Show according to Figure 2 A graphical representation of with highlighted areas. DETAILED DESCRIPTION

[0041] Figure 1 A production line 100 is shown, which includes a plurality of production stations 10, namely a first production station 10-1, a second production station 10-2, a third production station 10-3, a fourth production station 10-4 and an Nth production station 10-N, wherein N indicates that any number of additional production stations may be included.

[0042] The production line 10 produces a total number of X parts per hour. The corresponding production station 10 has a defect rate Q of defective parts produced per hour. There is a remaining time t before the next planned maintenance. rest The scrap quantity X is calculated based on the following formula aus , where each factor X, Q, t rest Multiply each other:

[0043]

[0044] Here the total number X is given as parts per hour, the defect rate is given as a percentage of the total number X and the remaining time t rest Given in hours.

[0045] Unplanned maintenance requires maintenance time t wart During this period, no parts can be produced in production line 100. The number of parts not produced during this period is the downtime number X nicht . Number of downtimes X nicht By maintenance time t wart It is calculated by multiplying it with the total number X. In a possible embodiment, in order to calculate the number of downtimes X, the defect rate Q is also taken into account.

[0046] For decision support, the number of shutdowns X nicht and the amount of waste X aus Once the scrap quantity X aus Greater than or equal to the number of shutdowns X nicht , unplanned maintenance is recommended.

[0047] Figure 2 A graphical representation for a production line is shown, which displays a decision support on a display screen of a PC (personal computer) for deciding whether unplanned maintenance or planned maintenance should be carried out during the production process at at least one production station 10 of a production line 100 .

[0048] The graphical representation has an X-axis and a Y-axis. The X-axis represents the defect rate Q at even intervals. The defect rate Q represents the number of defective parts produced per hour. In the present embodiment, the defect rate Q is given as a percentage of the total number X. The Y-axis represents the remaining time t until the next planned maintenance at even intervals. rest (in hours). The values ​​shown on the X-axis and Y-axis can also be swapped with each other.

[0049] In addition, the graphical representation has three regression lines, each of which represents a decision point E1, E2 and E3. Figure 2 As shown in , if the production line produces parts at a certain point in time and the resulting value is in the area to the left of decision point E1, E2 or E3, it is recommended to continue production. Figure 2 As shown, if the production line produces parts at a certain point in time and the resulting value is in the area to the right of decision point E1, E2 or E3, it is recommended to implement unplanned maintenance.

[0050] The first decision point E1 represents a line, on which the number of scraps X aus Equal to maintenance time t wart The number of downtimes at 10 minutes is X nicht The second decision point E2 represents a line on which the number of scraps Xaus Equal to maintenance time t wart The number of downtimes at 20 minutes is X nicht The third decision point E3 represents a line on which the number of scraps X aus Equal to maintenance time t wart The number of downtimes at 60 minutes is X nicht .

[0051] For clarity, an example is described below.

[0052] In the first example, the remaining time t rest 5 hours. Production line 10 has a 10% defect rate Q. The number of scrapped products X aus is 700 pieces. At maintenance time t wart When the shutdown time is 60 minutes, the number of shutdowns is X nicht The number of pieces is 1323. Maintenance time t wart It is defined based on the determined fault of production station 10. At present, 60 minutes of maintenance time is required.

[0053] At maintenance time t wart When the time is 60 minutes, the number of waste products is X aus Less than the number of downtime X nicht In the graphical representation, according to the remaining time t rest The defect rate Q shows a point Bsp1, which is located on the left side of the third decision point E3 for the 60-minute unplanned maintenance. Therefore, it is recommended not to perform unplanned maintenance, but to produce with an increased defect rate Q until the next planned maintenance.

[0054] In the second example, the remaining time t rest is 8 hours. Line 10 has a 6% defect rate. Number of scraps X aus is 1100 pieces. At maintenance time t wart When the shutdown time is 20 minutes, the number of shutdowns is X nicht 770 pieces. The number of scraps is X aus Greater than the number of downtimes X nicht In the graphical representation, according to the remaining time t rest The defect rate of 6% shows a point Bsp2, which is located on the right side of the second decision point E2 for 20 minutes of unplanned maintenance. Therefore, it is recommended to implement unplanned maintenance.

[0055] according to Figure 3 The difference from the graphical representation of FIG. 1 is that additional regions Ber1, Ber2, Ber3, Ber4, Ber5 are shown in this graphical representation. The first region Ber1 shows the number of rejects X between 0 and 200 of the produced defective parts in a uniform color. ausThe second area Ber2 shows the scrap quantity X between 201 and 400 defective parts produced in a uniform color. aus The third area Ber3 shows the scrap quantity X between 401 and 600 defective parts produced in a uniform color. aus The fourth area Ber4 shows the scrap quantity X between 601 and 700 defective parts produced in a uniform color. aus The fifth area Ber5 shows the number of rejects X between 701 and more defective parts produced in a uniform color. aus .

[0056] It is particularly advantageous to display the current values ​​of the production line in real time in the graphical representation. In addition, historical data are preferably also displayed.

[0057] Graphical representations enable simple and intuitive decision support.

[0058] Reference numerals list

[0059] 10 production stations

[0060] 10-1 The first production station

[0061] 10-2 Second production station

[0062] 10-3 The third production station

[0063] 10-4 The fourth production station

[0064] 10-N Nth production station

[0065] 100 production lines

[0066] X is the total number of components per time unit

[0067] QDefect rate of defective parts produced per time unit

[0068] t rest time left

[0069] X aus Quantity of scrap

[0070] t wart Maintenance time

[0071] X nicht Number of downtimes

[0072] E1 decision point

[0073] E2 Decision Point

[0074] E3 decision point

[0075] Bsp1 first example

[0076] Bsp2 Second Example

[0077] Ber1 first region

[0078] Ber2 second region

[0079] Ber3 Third Area

[0080] Ber4 Region 4

[0081] Ber5 fifth area

Claims

1. A method for generating decision support for determining whether unplanned maintenance or planned maintenance should be performed during a production process at at least one production station (10) of a production line (100), the production station (10) being configured to produce a total number (X) of parts per time unit, the production station (10) having a defect rate (Q) of defective parts produced per time unit, the method comprising the following steps: a) Determine the remaining time until the next planned maintenance (t rest ); b) Based on the total number (X), remaining time (t rest ) and the defect rate (Q) determine the number of defective parts that will be scrapped until the next scheduled maintenance (X aus ); c) Determine the maintenance time (t wart ); d) Based on the total number (X) and maintenance time (t wart ) determines the maintenance time (t wart ) during which no parts were produced (X nicht ); as well as e) The quantity of waste (X aus ) and the number of downtimes (X nicht ) and display decision support based on the comparison.

2. The method according to claim 1, characterized in that If the scrap quantity (X aus ) is greater than or equal to the number of shutdowns (X nicht ), it indicates that unplanned maintenance should be performed.

3. The method according to claim 1 or 2, characterized in that: The maintenance time (t wart ) is defined by the fault identified.

4. The method according to any one of the preceding claims, characterized in that The decision support is displayed in a graphical representation.

5. The method according to any one of the preceding claims, characterized in that The decision support displays a decision point at which the quantity of scrap (X aus ) is equal to the number of shutdowns (X nicht ).

6. The method according to any one of the preceding claims, characterized in that The amount of waste (X aus ) includes the number of parts produced that exceed the defined product specifications.

7. The method according to any one of the preceding claims, characterized in that The production line (10) comprises at least two production stations (10-1, 10-2, 10-3, 10-4, 10-N).

8. System for data processing, comprising means for performing the steps of the method according to any one of claims 1 to 7.

9. Computer program product comprising instructions which, when said program is executed by a computer, cause the computer to perform the method according to any one of claims 1 to 7.

10. A vehicle (200) having a vehicle component which is manufactured in a production line, in which a decision is made with the aid of a method for generating decision support according to any one of claims 1 to 7 whether planned maintenance or unplanned maintenance is to be carried out.

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