Method for populating circuit boards by means of a plurality of setups on an assembly line over a short planning period
Patent Information
- Application Number
- EP2024710649
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-02
- Filing Date
- 2024-02-26
- Publication Date
- 2025-12-03
AI Technical Summary
In electronics production, the high setup effort required for variable armaments in assembly lines leads to increased changeover times and production downtimes, especially when producing small batches of diverse products, as existing methods do not effectively minimize the setup effort for assembly types not included in fixed setups.
A method that optimizes the assignment of printed circuit board types to fixed and variant setup families, using Mixed Integer Non-Linear Programming to minimize the expected number of component types needed for variant setups, allowing for flexible production with reduced setup effort and shorter changeover times by forming a fixed setup that remains unchanged during a planning horizon and temporarily setting up variant setups.
This approach reduces setup effort and changeover times, enabling efficient production of low-batch-size products with increased flexibility, allowing for reduced production times and minimized downtimes by optimizing the assignment of circuit board types to setup families, thereby enhancing production efficiency.
Smart Images
Figure EP2024054842_06092024_PF_FP
Abstract
Description
[0001]202302559 Foreign version 1 Description Method for assembling printed circuit boards using multiple setups on an assembly line over a short-term planning period. The invention relates to a method for assembling printed circuit boards using multiple setups on an assembly line, wherein each setup comprises a number of component types sufficient to assemble a setup family of printed circuit board types assigned to the setup, and to a control device and an associated computer program product. Particularly in the field of electronics production, printed circuit boards or assemblies to be manufactured are manufactured on SMT assembly lines using surface mounting (SMT = surface mounted technology). Electronics production or manufacturing is characterized by high demands on short throughput times, high productivity (including short changeover times, short production times, etc.), and high flexibility. Several automatic assembly machines,which are usually connected by a transport system and which work together, for example, to manufacture or produce or assemble (electronic) assemblies, represent an assembly line. In industrial manufacturing plants in the field of electronics production, assemblies (or circuit boards) to be manufactured are produced in orders with fixed batch sizes. The batch sizes implicitly determine how frequently an assembly type is to be produced. The smaller the batch size of an assembly type, the more frequently assemblies of this assembly type have to be produced and the greater the setup effort. 202302559 Foreign version 2 In variable production, the assemblies to be manufactured are divided into setup families for a short-term (planning) period (usually 1-3 days) within a longer-term planning horizon or period (usually at least 6 months). A setup family is a set of assembly types,that can be produced with one component setup on the assembly line. In other words, a setup family, also called a cluster, comprises a set of batches that can be manufactured within one setup. All assemblies of the assembly types of a setup family can therefore be manufactured consecutively on the assembly line without retooling. The setups of the setup families are set up for production and then taken down again. (These setups are referred to as variable setups or variant setups.) The retrieval and manual setup of the conveyors onto the shuttle tables in the pre-setup area requires approximately 6-10 hours for all (shuttle) tables of a setup family and is therefore very time-consuming. In fixed setup production, the setups for the assemblies to be manufactured are set up on shuttle carriages / tables for a longer period of time (6-12 months). If a line is operated with a fixed setup,This way, the shuttle tables remain firmly in place on the line. If there are several fixed setups per line, the shuttle tables are swapped accordingly when the setup family changes. In practice, the replacement of entire fixed setups is preferred. Setting up and dismantling shuttle tables is no longer necessary in daily production. 202302559 Foreign version 3 Variable or variant production is in great demand in the high-mix-low-volume sector, i.e., a large number of different assembly types must be manufactured in small quantities. In this sector, production is also operated in a mixed manner, if possible, i.e., some of the products are manufactured with fixed setups and others with variant setups. The biggest problem is usually the setup effort for the variable setups. Fixed setups in this sector are then mainly used toto reduce the setup effort for the variable setups. In addition, the use of fixed setups can also avoid line downtimes if variable setups are not completed on time. EP 2893791 B1 discloses a method for determining a fixed setup for an assembly line. This method can be used to create fixed setup families that are designed for a long period of time or have the longest possible runtime, or with which as many orders as possible can be manufactured. Fixed setups that aim to minimize the setup effort for assemblies that are not manufactured with fixed setups cannot be created this way. The object of the invention is to develop a method that is improved over the above-mentioned prior art, as well as an associated control device, in which at least one fixed setup is created for a set of assembly types,wherein the setup effort for assembly types that cannot be manufactured in the fixed setup is minimized. This object is achieved by the independent claims. Advantageous further developments are the subject of the dependent claims. 202302559 Foreign version 4 The invention claims a method for assembling printed circuit boards using multiple setups on an assembly line, wherein one setup comprises a number of component types sufficient to assemble a setup family of circuit board types assigned to the setup, - wherein one setup can be implemented by a number of shuttle tables that are attached to the assembly line and contain stocks of components of the component types, - wherein a planning horizon for assembling the printed circuit boards is divided into several time intervals of fixed length, and during a time interval, different setups can be attached to the assembly line,- wherein at least one fixed setup is formed from the setups, which remains unchanged during the planning horizon and can be used multiple times on the assembly line, - and wherein at least one variant setup is formed during the planning horizon, which is only temporarily set up on shuttle tables and is dismantled again after the assembly of circuit boards of a setup family, and wherein the method comprises the following steps: a) Recording a set of circuit board types with circuit boards assigned to the respective circuit board type, which are to be assembled on the assembly line within the planning horizon; b) Recording the number of component types for assembling one or more circuit boards of a circuit board type,c) Recording probabilities for the arrival of orders for the respective assembly of a circuit board type within a time interval; d) Assigning circuit board types from the set of circuit board types to a fixed setup family, whereby all component types for assembling a circuit board of a circuit board type of the assigned circuit board types have space in the tracks available in the fixed setup and are equipped in the fixed setup with regard to their space consumption; e) Optimizing the assignment of the circuit board types to the fixed setup families such that the number of component types expected to be equipped in a variant setup within a time interval is minimized,f) Assembling the printed circuit boards of all orders to be executed in the time intervals on the assembly line using the optimized assignment of the printed circuit board types. In other words, the optimization minimizes the expected value of the sum of the component types to be assembled. The planning horizon is longer than one time interval, preferably longer term (usually longer than half a year). It is divided into several time intervals of fixed length. These time intervals preferably represent short-term periods.which usually last 1 to 3 days. As a rule, the variant setups are set up and dismantled during such a time interval. The length of the time intervals is specified in the method according to the invention and is independent of the orders and the length of the planning horizon. Preferably, a forecasted number of orders for a circuit board type is recorded within the planning horizon. It is assumed thatthat a maximum of one order for a circuit board type is manufactured in a short-term period. Accordingly, the forecast number is less than or equal to the number of short-term periods. An (assembly) order comprises a number of units or a quantity of assemblies of an assembly type. The orders are generally evenly distributed across the time intervals. Thus, the probability of the arrival of 202302559 foreign version 6 orders for the respective assembly of a circuit board type within a time interval results from the forecast number of orders divided by the number of time intervals, whereby a maximum of one order can be completed per time interval. The invention thus has the advantage of increasing the flexibility in the production of the assemblies and the products in which the manufactured assemblies are to be used. The setup effort in the pre-setup area is reduced,This results in shorter changeover times. Production times and downtimes are reduced. Production with small batch sizes is possible. The above method can be iterated as often as desired. The method according to the invention and its further developments / embodiments can be carried out centrally on a control device, preferably of the type described below. The optimization of the assignment of the circuit board types can be aborted if no assignment could be found during a predetermined processing time. The result of the optimization of the assignment of the circuit board types can be output in a form suitable for controlling the assembly of these components, preferably in a computer-readable format, and can then be used to control or regulate the assembly of the components, for example with a control device, for example of the type specified below. In the above method,which is preferably computer-implemented, "captured" or "capturable" or "specified" or "specifiable" can be understood to mean that one or more input values are already specified, for example, by standard values, or are specified or determined by a user and / or by output values of an upstream computer-implemented process and / or are specifiable or determinable. Thus, these input values are captured by the computer-implemented process. The optimization of the assignment of the circuit board types can be performed using Mixed Integer Non-Linear Programming (MINLP). A special case of optimization methods that can be used for the above-mentioned optimization is linear optimization. It deals with the optimization of linear objective functions over a set,which is constrained by linear equations and inequalities. It forms the basis of the solution methods of (mixed-) integer linear optimization. More difficult than linear optimization is the case of nonlinear integer optimization (MINLP), where the objective function, the constraints (NB), or both can be nonlinear. The solution is achieved by using suitable linear approximations, so that standard solvers can be used directly. In addition, the standard solvers mentioned above can each solve certain types of nonlinear problems. There are also additional solvers that are specialized for solving nonlinear problems (e.g., ANTIGONE,BARON). In Mixed Integer Nonlinear Programming, the nonlinear objective function can be approximated by a linear objective function. The minimization of the nonlinear objective function in the form of a minimization of the expected number of component types to be equipped in at least one variant setup can be approximated by maximizing the linear objective function in the form of the sum of the forecast orders multiplied by the number of component types of the circuit board types assigned to the fixed setup families. The aforementioned optimization of the assignment of the circuit board types can be carried out using Mixed Integer Linear Programming with the linear objective function. Mixed Integer Programming represents a global optimization approach that is easily expandable and for which commercial solution methods or solution devices, also called solvers, are available.are available. Using mixed integer programming, global maxima can be found in a multitude of possible solutions, so that a particularly good solution can be found. In conjunction with MIP (mixed integer programming) or MILP (mixed integer linear programming), standard solvers such as CPLEX, Scip, Gurobi, and Xpress can be used for small IP programs (integer optimization models). It is expedient that the assignment of circuit board types to the setup families takes place under the boundary condition that a maximum fill level of the shuttle tables or a maximum space consumption on the shuttle tables is not exceeded. Furthermore, it is expedient that the sum of the production times of the assembly types of a setup family must not fall below a lower production time limit. A further aspect of the invention provides a control device, in particular comprising at least one computing unit or processor,This control device is designed for assembling printed circuit boards using a setup on an assembly line, wherein the setup comprises a number of component types sufficient to assemble a setup family of printed circuit board types assigned to the setup, - wherein the setup is implemented by a number of shuttle tables that are attached to the assembly line and that contain stocks of components of the component types, - wherein a planning horizon for assembling the printed circuit boards is divided into several time intervals of fixed length, and 202302559 Foreign Version 9 different setups can be attached to the assembly line during a time interval, - wherein at least one fixed setup is formed from the setups, which remains unchanged during the planning horizon and can be used multiple times on the assembly line, - and wherein at least one variant setup is formed during the planning horizon,which is only temporarily set up on shuttle tables and dismantled again after the assembly of circuit boards of a setup family, and wherein the control device is configured to carry out the above-mentioned steps. The control device or control system according to the invention can be centrally located for several assembly lines. One or more control devices, each responsible for the individual assembly lines, can be connected to the control device. The control device can also be located remotely from the control device(s) and, if necessary, outside the production plant in a data center or in a cloud (computer cloud). It is also possiblethat one control device is provided for each of several assembly lines or one control device per assembly line. In the latter decentralized solution, the multiple control devices communicate with each other via a wired and / or wireless communication network. The device(s), the system or device(s) and any associated unit(s) are configured to carry out such method steps and can be implemented in hardware, firmware, and / or software. A further aspect of the invention is a computer program (product) comprising a program code executable by a computing unit or processor or a plurality of program code modules executable and interacting by a plurality of computing units, which has or have commands that enable the execution of the method according to one of the above-mentioned embodiments on a control device,preferably of the type mentioned above. The computer program or product can be stored on a computer-readable storage medium or data carrier. It is possible for the computer program (product) to be embedded in a data carrier signal intended for downloading it from a server to a storage medium. The computer program or product can be created in a common programming language (e.g., C++, Java). A processing device or processor for executing its program code / program code modules can comprise a commercially available computer or server with corresponding input, output, and storage means. This processing device or computing unit can be integrated into the control device or apparatus or into its units. The computer-implemented method also relates to so-called cloud services (cloud = computer cloud). A computer cloud typically comprises one or more servers,which are operated by a cloud service provider and are configured to deliver a cloud service to a service user, e.g., a network of companies. Accordingly, the system can be implemented in a computer cloud. The control devices or control apparatuses, as well as the computer program (product) and computer-readable media or data carriers or data carrier signals, can be developed or configured analogously to the above-mentioned method and its further developments. Further advantages, details, and further developments of the invention will become apparent from the following description of exemplary embodiments in conjunction with the drawings. Figure 1 shows an example of a placement system.and 202302559 Foreign version 11 Figure 2 shows a flow diagram of the method according to the invention. Figure 1 shows a placement system 100 with one or more placement lines. The placement system 100 comprises one or more placement lines 110 and a control system 115. Each placement line 110 comprises an optional transport system 125 and one or more placement machines 130. Each placement machine 130 comprises one or more placement heads 135, each of which is configured to pick up components or parts 155 from a shuttle table 140 and to position them at a predetermined position on the assembly or printed circuit board 120 located on the transport system 125. During the placement process, the printed circuit board 120 is usually stationary with respect to the placement machine 130. The changing tables 140 each comprise a plurality of conveyors or feeding devices 150,of which only one is shown as an example in Figure 1. Each feeder 150 holds a supply of components 155 of a predetermined component type 160. The feeder 150 has a capacity for the components 155, which is usually expressed in tracks. A track is usually 8 mm wide, and the number of tracks in each feeder 150 is limited, for example, to 40. Components 155 of the same component type 160 are usually provided in a belt, on a tray, or in a tube. Each component type 160 requires space in the feeder 150 with a predetermined number of tracks.which usually have to be adjacent to one another. Each feeder device 150 can be configured to hold different components 155, and usually different feeders 150 can be attached to a shuttle table 140. If a component 155 of a component type 160 is required on the pick and place machine 130 that is not present in one of the shuttle tables 140, then usually one of the attached shuttle tables 140 is not provided with the required components 155, but is completely replaced with another, appropriately equipped shuttle table 140. Upgrading a shuttle table 140 to be exchanged with components 155 is called pre-equipment and can require a processing time in the range of hours. Since a change of shuttle tables 140 on the assembly line 110 is usually associated with a production stoppage, the aim is toto perform as infrequent changes of the change tables 140 as possible. A placement order comprises the number of printed circuit boards of a printed circuit board type to be assembled. To assemble a quantity of printed circuit boards 120 that can be predetermined based on the placement orders, setups can be formed, each of which comprises stocks of components 155 of predetermined component types 160, whereby each printed circuit board of the quantity of printed circuit boards 120 can be completely equipped with components 155 of the setup. A setup can be realized by a number of change tables 140. In the illustration in Figure 1, a fixed setup 165, whose change tables 140 are attached to the assembly line 110, and a variant setup 170, whose change tables 140 are separate from the assembly line 110, are shown.formed. One or more fixed setups 165 and one or more variant setups 170 can be provided. A case without variant setups 170 is possible. The fixed setup 165 is designed to remain unchanged or existing with regard to its component types 160, at least during a long-term planning horizon, which can be, for example, half a year or more, or even a year. Therefore, if necessary, components 155 can be replenished at the shuttle tables 140 of the fixed setup 165, but the assignment of component types 160 to tracks of the shuttle tables 140 remains unchanged. If several fixed setups 165 are provided, they can be interchanged within the planning horizon. A variant setup 170, on the other hand, is designed to accommodate components 155 of different component types 160 during the planning horizon,However, this only exists temporarily. For this purpose, the shuttle tables 170, while not attached to the assembly line 110, are typically stripped of components 155 of predetermined component types 160 and reloaded with components 155 of other component types 160. This reloading can involve a significant amount of manual work and be time-consuming. A reloading family, whether a fixed-loading family or a variant-loading family, is defined as a set of circuit board types whose circuit boards can be assembled on an assembly line without changing the set of component types that are held ready for assembly on the assembly line. This means that reloading is not necessary. A control device or apparatus 115 assigns circuit board types 122, whose associated circuit boards 120 are to be assembled on the assembly line 110,a setup family. It also controls the assembly of the printed circuit boards. A setup family is a set of printed circuit board types 122 whose printed circuit boards 120 can be fully assembled with components 155 that are provided in the assigned setup 165, 170. A setup family is / is usually assigned to exactly one setup 165, 170 and vice versa. One or more control devices, each configured for one or more assembly lines 110 to control / regulate the component assembly process on the assembly lines 202302559 Foreign Version 14 to fulfill the assembly orders, can each be connected to a (central) cloud or computer cloud via wired and / or wireless network technologies. The control device can comprise a computing unit,which can be connected to a data storage device or medium (not shown). Stored or preconfigured models of the assembly systems can be retrieved from the data storage device, if necessary. Furthermore, one or more optimization units (not shown) can be integrated into the control unit or linked to it, in which so-called solvers can be used. Solvers are special mathematical computer programs that can solve mathematical problems numerically. An output unit (not shown) of the control unit can provide the optimization result described in more detail below in a form suitable for controlling and / or regulating the assembly order fulfillment. Such a form should be computer-readable, e.g., one or more Excel lists in CSV format. The effects of the optimization result can then be evaluated, preferably by means of simulation.include an optimized allocation of the circuit board types to the operation of the assembly line. A target function of the aforementioned optimization should reach its maximum or a predeterminable key figure. Additionally and alternatively, it is possible for the control device to send or receive other computer-readable control signals in order to initiate the control / regulation process in its processing unit. The assembly of the modules or circuit boards is usually carried out in such a way that the components 155 are individually fixed to the circuit boards 120 using solder paste. The assembled circuit boards 155 can then be finished in a reflow oven in which the solder paste is temporarily melted.so that the components 155 are electrically and mechanically connected to conductor tracks on the surface of the circuit board 120. Figure 2 shows a flowchart of the method according to the invention, comprising the following steps labeled a to f: a: Determining a number of circuit board types with circuit boards assigned to the respective circuit board type, which are to be assembled on the assembly line within the planning horizon; b: Determining the number of component types for assembling one or more circuit boards of a circuit board type; c: Determining probabilities for the arrival of orders for the respective assembly of a circuit board type within a time interval; d: Assigning circuit board types to a fixed assembly family;where all component types for assembling a printed circuit board of a printed circuit board type of the assigned printed circuit board types have space in the tracks available in the fixed setup with regard to their space requirements and are assembled in the fixed setup; e: Optimizing this assignment of the printed circuit board types such that the expected number of component types to be assembled in the at least one variant setup in a time interval is minimized; f: Assembling the printed circuit boards of all orders to be executed in the time intervals on the assembly line using the optimized assignment of the printed circuit board types. Optionally in step e: For step e, various additional conditions can be considered, which are described in more detail, for example, in the following formulation of a mixed integer program. This step can also be skipped.Then, step e follows step f. Optionally, the process is repeated to further optimize the assignment of the circuit board types if necessary. To achieve an optimization of the assignment of the circuit board types, any optimization methods can be used, for example, based on local search methods or metaheuristic algorithms. With each iteration of the above steps, the best assignment determined so far is varied pseudo-randomly or according to a heuristic, resulting in modified assignments.from which the optimal assignment is selected. Preferably, step e is performed by solving a mixed integer program. Optimizers (solvers) based on mixed integer programming are available as commercial products, as already explained above. The following is an example of a MINLP and MILP formulation for optimizing the assignment of circuit board types. According to the invention, for a high-mix, low-volume line, assembly types for fixed setup families are selected so that the expected number of setups of component types for creating the variable setups in the following example is minimized per day. This minimizes the overall setup effort. Evaluation model: Order, r Number of forecast orders for the assembly group r in the long-term planning period 202302559 Foreign version 17 T L Number of days in the long-term planning period T KNumber of days in the short-term planning period (referred to above as time interval) ≤ T L / T K . (If this is not the case := T / T.) L K p r = Probability that the assembly will be manufactured in the short-term planning period. It is assumed that the orders are evenly distributed across the short-term planning periods. ^^^ ^^ ^^ ^^ ^^ ^^^ It is further assumed that the orders are independent of each other and that, in a short-term planning period, the setups of the setup family have hardly any component type overlaps. (This is approximately the case, for example, in the Fürth electronics plant.) A component type is therefore setup at most once in a short-term planning period. The expected value that a component c ^ C must be setup in the short-term planning period is calculated as follows: EW(c) = Probability that at least one assembly type r must be manufactured that contains the component type c = 1 – Probability that none of these assembly types must be manufactured 202302559 Foreign version 18 ൌ1 െ ^^1 െ ^^^^ The expected value for the number of component types to be equipped in a short-term planning period is: ^^ ^^^Number of component types to be equipped^ ൌ ^ ^^ ^^^ ^^^ In the following simplified example, the following expected values result: ^^ ^ ൌ ^ ^^ ^ , ^^ ଶ ^ 50 orders ^ Orders ^ ^ ^^ ^ ^^^ ^ ൌ 1 െ ^ 1 െ 0,5 ^ଶ ൌ 1 െ 0.25 ൌ 0.75Orders Orders ^^^ ^^ ^ ^ ൌ 1 െ ^1 െ 0,9^^1 െ 0,1^ ൌ 1 െ 0,1 ∗ 0,9 ൌ 0,91 of component types in different va- are not considered. Data- Evaluations from an electronics plant have shown that the setups created exhibit hardly any overlap of component types. Therefore, this assumption can be made. The fixed setups should be optimized with the goal of minimizing the setup effort for the variable setups. r,cl Variable that specifies whether the assemblies of type r are assigned to the fixed setup family cl. (In this case, it takes the value 1, otherwise the value 0) assign rVariable that indicates whether the assemblies of type r are not assigned to a fixed armament family. (In this case, it takes the value 1, otherwise the value 0) 202302559 Foreign Version 19 The following applies: ^^ ^^ ^^ ^^ ^^ ^^^ ൌ 1 െ ^ ^^ ^^ ^^ ^^ ^^ ^^^,^^^^∈^^ Objective function: Minimize the expected value of the total number of components to be equipped. The armament effort arises for the variable armaments. As a rule, no armament effort arises for the fixed armaments. ^ ^^ ^^^ ^^^ ൌ ^ 1 െ ^ ^ 1 െ ^^^ ^ The associated optimization problems are difficult to solve. Therefore, a heuristic solution approach with a heuristic linear objective function is also proposed. This objective function is derived below. Objective function for the heuristic MIP solution approach: Factors: ^1 െ ^^ ^ ^ ^^^^^^^ ൌ 1 െ ^^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^202302559 Foreign version 20 The product can be decomposed into linear terms and higher order terms ^^1 െ ^^^ ^^ ^^ ^^ ^^ ^^ ^^^^െ . . . linear components to be minimized. ^^ ^^ ^^ ^ ^ ^^ ^^ ^^ ^^ ^^ ^^ of the assembly r ^^ ^^ ^^^ ^ ^^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^ you get: to minimize the overall setup effort ∑ ^∈^ ^^ ^^^ ^^^ 202302559 Foreign version 21 ^^ ^^ ^^^ ^^ ^^^ ^^^ → ^^ ^^ ^^^ ^^^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^ The following MINLP or MIP model is proposed as a heuristic approach to minimize the component types to be equipped for the variable setups: MINLP / MIP model: The following notations apply. Indices C Set of component types R Set of assembly types R c Set of assembly types with component type c Cl Quantity of fixed armor / fixed armor families Parameter Width cSpace consumption of a component type c in lanes LineCap Number of lanes of the component types that have space in the setup of a setup family LowerTimeLimit Lower production time limit of all assemblies assigned to the fixed setup family ProdTime r Production time of an assembly of type r on the line Order r Number of forecast orders for the assembly type to be manufactured r Comps r Number of component types with which assembly type r is to be equipped 202302559 Foreign version 22 Binary variables assign r,cl Variable that specifies whether the assemblies of type r are assigned to the fixed setup family cl. (In this case, it takes the value 1, otherwise the value 0) setup c,cl Variable that specifies whether component type c must be equipped in the armor of the fixed armor family cl. (In this case, it takes the value 1, otherwise the value 0) MINLP objective function ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^ ^ ^^ ^^ ^^ ^^ ^^ ^ Comps ^ ^^ ^^ ^^ ^^ ^^ ^^ ^,^^ ^^∈^^ ^∈ோ Constraints: (1) Each assembly type may be assigned to a maximum of one setup family. ^ assign r,cl ^ 1 ^^ ∈ ^^ ^^ ^^∈ ^^ ^^ one Armor family must fit into one armor. ^Width c ^^ ^^ ^^ ^^ ^^ ^^, ^^ ^^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ∈ ^^ ^^ ^^∈ ^^ in the 202302559 Foreign version 23 ^ assign r,cl ^ | ^^ ^^ | ^^ ^^ ^^ ^^ ^^ ^^, ^^ ^^ ^^ ∈ ^^, ^^ ^^ ∈ ^^ ^^ ^ ^∈ ^^ ^^ (4) Optional: The sum of the production times of the assembly types of a setup family must not fall below the lower production time limit. ^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^^, ^^ ^^ ProdTime ^^ ^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^∈ ^^ ^^ ^^∈ ^^ ^^ ^^ ^^ ^^ ^^ ^^^ ൌ 1 െ ^ ^^ ^^ ^^ ^^ ^^ ^^^,^^^^ ∈ ^^ ^^∈^^ (6) Variable restrictions assignr,cl ∈ ^ 0,1^^^ ∈ ^^, ^^ ^^ ∈ ^^ ^^setupc,cl ∈ ^0,1^ ^^ ∈ ^^, ^^ ^^ ∈ ^^ ^^assignr ∈ ^0,1^ ^^ ∈ ^^Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited to the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. The processes or method sequences / steps described above can be implemented using commands or instructions that are present on computer-readable, non-volatile storage media or in volatile computer memories (hereinafter collectively referred to as computer-readable memories). Computer-readable memories include, for example, volatile memories such as caches, buffers or RAM 202302559 Foreign Version 24 as well as non-volatile memories such as removable media, hard drives, etc.The functions or steps described above can be present in the form of at least one instruction set in / on a computer-readable memory. The functions or steps are not tied to a specific instruction set or to a specific form of instruction sets, to a specific storage medium, to a specific processor, or to specific execution schemes, and can be executed by software, firmware, microcode, hardware, processors, integrated circuits, etc., either alone or in any combination. A wide variety of processing strategies can be used, for example serial processing by a single processor, multiprocessing, multitasking, or parallel processing, etc. The instructions can be stored in local memory, but it is also possible to store the instructions on a remote system, e.g., the cloud, and access them via the network.In the context of the invention, “computer-assisted” or “computer-implemented” can be understood as meaning, for example, an implementation of the method in which, in particular, a processor or a computing unit, which can be part of the control system or control device or the (control or processing) apparatus or unit and / or a computer and / or one or more services in a computer cloud of a service provider, carries out at least one method step of the method.Unless otherwise stated in the following description, the terms "mapping", "replicating", "receiving", "applying", "outputting", "providing" and the like preferably refer to actions and / or processes 202302559 Foreign Version 25 and / or processing steps that change and / or generate data and / or convert the data into other data, wherein the data can in particular be represented or present as physical quantities.The term "processor," "central signal processing," "control unit," or "data evaluation means," as used here, encompasses processing means in the broadest sense, such as servers, general-purpose processors, graphics processors, digital signal processors, application-specific integrated circuits (ASICs), programmable logic circuits such as FPGAs, discrete analog or digital circuits, and any combinations thereof, including all other processing means known to those skilled in the art or developed in the future. Processors can consist of one or more systems, devices, or units. If a processor consists of multiple devices, these devices can be designed or configured for parallel or sequential processing or execution of instructions.In the context of the invention, a “storage unit” can be understood as meaning, for example, a computer-readable storage medium in the form of random access memory (RAM) or a hard disk.
Claims
202302559 Foreign version 26 claims 1. Method for assembling printed circuit boards (120) by means of several setups (165, 170) on an assembly line (110), wherein one setup (165, 170) comprises a number of component types (160) which is sufficient to assemble a setup family (210, 215) of printed circuit board types (122) assigned to the setup (165, 170), - wherein one setup (165, 170) can be realized by a number of changing tables (140) which are attached to the assembly line (110) and which comprise stocks of components (155) of the component types (160), - wherein a planning horizon for assembling the printed circuit boards is divided into several time intervals of fixed length and during a time interval different setups (165, 170) can be attached to the assembly line (110), - whereby at least one fixed armouring (165) is formed by the armourings,which remains unchanged during the planning horizon and can be used multiple times on the assembly line (110), - and wherein at least one variant setup (170) is created during the planning horizon, which is only temporarily upgraded on shuttle tables (140) and dismantled again after the assembly of circuit boards (120) of a setup family, and wherein the method comprises the following steps: a) detecting a set of circuit board types (122) with circuit boards (120) assigned to the respective circuit board type, which are to be assembled on the assembly line (110) within the planning horizon (205); b) detecting the number of component types for assembling one or more circuit boards of a circuit board type, c) detecting probabilities for the arrival of orders for the respective assembly of a circuit board type within a time interval;, 202302559 Foreign Version 27 d) Assigning (315) a subset of circuit board types (122) from the set of circuit board types to a fixed setup setup family, wherein all component types for assembling a circuit board of a circuit board type of the assigned circuit board types have space in the tracks available in the fixed setup with regard to their space consumption and are equipped in the fixed setup; e) Optimizing the assignment of the circuit board types to the fixed setup setup families such that an expected number of component types to be equipped in a variant setup in a time interval is minimized, f) Assembling the circuit boards (120) of all orders to be executed in the time intervals on the assembly line (110) with the aid of the optimized assignment of the circuit board types. 2.Method according to claim 1, characterized in that a forecast number of orders for a circuit board type is recorded within the planning horizon and the probability of orders arriving for the respective assembly of a circuit board type within a time interval results from the forecast number of orders divided by the number of time intervals, whereby a maximum of one order for a circuit board type can be completed per time interval.
3. Method according to claim 1 or 2, characterized in that the aforementioned optimization of the assignment of the circuit board types takes place by means of mixed integer non-linear programming.
4. Method according to claim 3, characterized in that in the mixed integer non-linear programming the non-linear objective function is approximated by a linear objective function. 202302559 Foreign Version 28 5. The method according to claim 4, characterized in that the minimization of the nonlinear objective function in the form of a minimization of the expected number of component types to be equipped in the at least one variant setup is approximated by maximizing the linear objective function in the form of the sum of the forecast orders multiplied by the number of component types of the circuit board types assigned to the fixed setup families.
6. The method according to one of claims 4 or 5, characterized in that the said optimization of the assignment of the circuit board types is carried out with the aid of mixed integer linear programming with the linear objective function.
7. Control device (115) for assembling printed circuit boards (120) by means of a rack (165, 170) on an assembly line (110), wherein the rack (165, 170) comprises a number of component types (160),which is sufficient for assembling a family of circuit board types (122) assigned to the assembly (165, 170), - wherein the assembly (165, 170) can be implemented by a number of shuttle tables (140) that are attached to the assembly line (110) and that contain stocks of components (155) of the component types (160), - wherein a planning horizon for assembling the circuit boards is divided into several time intervals of fixed length and during a time interval different assembly setups (165, 170) can be attached to the assembly line (110), - wherein at least one fixed setup (165) is formed from the setups, which remains unchanged during the planning horizon and can be used multiple times on the assembly line (110), - and wherein at least one variant setup (170) is formed during the planning horizon,which is only temporarily set up on changing tables (140) and is dismantled again after the assembly of printed circuit boards (120) of a setup family, 202302559 Foreign version 29 and wherein the control device (115) is configured to carry out steps a) to f) of claim 1.
8. Computer program product comprising a program code executable by a computing unit or a plurality of program code modules executable by a plurality of computing units and interacting, which or which have instructions that cause the execution of the method according to one of the preceding method claims on the control system according to the preceding claim, wherein the computer program product can be stored on a computer-readable medium.