Production line layout method

Abstract

The present application relates to a production line layout method, which includes selecting a product on the production line as a representative and calculating the planned production volume and cycle time of the production line. The planned production volume of the production line is calculated based on the planned production volumes of various products on the production line and the conversion coefficient, and the conversion coefficient is calculated based on the planned production volume of the product and the time quota; allocating operation elements based on precedence constraints and time constraints so that the operation time of the work area is as close as possible to the production line cycle time, thereby calculating the actual number of work areas, and the operation elements are obtained by decomposing the production line processes; calculating the mixed flow ratio of different products based on the actual number of work areas, the production batch of the product, and the time quota; and laying out the positioning information of production materials based on the actual number of work areas and the mixed flow ratio of different products, thereby completing the layout of the production line. This method solves problems such as production line balance, reasonable mixed flow ratio, and buffer configuration in layout design, and realizes dynamic adjustment of equipment spacing.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical engineering, and particularly to a production line layout method. Background Art

[0002] Generally, corresponding algorithms are often used in the layout design of production lines to solve the problem of finding the optimal or sub-optimal solution of the model under the combined objective constraints. Among them, multiple objectives such as cost, utilization rate, logistics, and convenience are usually adopted in the layout design. In this regard, domestic and foreign scholars have conducted in-depth research, which generally includes optimization methods such as operations research methods, nonlinear programming methods, genetic algorithms, simulated annealing algorithms, and particle swarms. For example, the method of graph theory is used to search for the optimal process route and alternative process routes. Based on the optimal process route, according to the relevant theories in queuing theory, the production layout is optimized and designed. Or a unified multi-objective programming mathematical model for the layout planning of an improved production system is established, and a hybrid algorithm combining a heuristic algorithm and a genetic algorithm is used for analysis and calculation. Or the processes of all the parts required to produce each product are combined to form an ordered graph, and its corresponding graph structure is abstracted into a directed tree. Based on the directed tree, a workshop floor layout planning scheme is obtained through the tree rotation processing algorithm and sequence clustering analysis. Or the production line layout problem is studied by using the method based on equipment classification and the method based on the function of the manufacturing system.

[0003] The existing research on the layout design of production lines analyzes and solves a specific layout problem by using corresponding algorithms under certain specific constraints and objectives, thus obtaining certain results. However, most of them focus on the sorting comparison of algorithms, resulting in a large gap between the obtained results and actual applications. There is a lack of a systematic method for analyzing, designing, and optimizing from the production system requirements combined with production factors, ignoring the characteristics of customization under multi-variety, variable batch, and cost constraints in production manufacturing, as well as the impact of production factors such as production capacity and load balance on the production line system layout. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a production line layout method, which combines the customized requirements under multi-variety, variable batch, and cost constraints faced by production manufacturing, comprehensively considers multiple production factors such as production capacity and production line balance, solves problems such as production line balance, rationalized mixed flow ratio, and buffer configuration in the layout design, and realizes the dynamic adjustment of equipment spacing, meeting the physical or logical variability of the production line layout and the requirement of customizable production capacity.

[0005] A production line layout method, the method comprising:

[0006] Select a product on the production line as a representative and calculate the planned production volume and cycle time of the production line. The planned production volume of the production line is calculated based on the planned production volumes of various products on the production line and the conversion coefficient, and the conversion coefficient is calculated based on the planned production volume of the product and the time quota.

[0007] Allocate operation elements based on precedence constraints and time constraints so that the operation time of the work area is as close as possible to the production line cycle time, thereby calculating the actual number of work areas. The operation elements are obtained by decomposing the production line processes.

[0008] Calculate the mixed flow ratio of different products based on the actual number of work areas, combined with the production batch of the product and the time quota.

[0009] Layout the positioning information of production materials based on the actual number of work areas and the mixed flow ratio of different products, thereby completing the layout of the production line.

[0010] In one embodiment, before selecting a product on the production line as a representative and calculating the planned production volume and cycle time of the production line, it further includes:

[0011] Obtain the production batch of the production line at the minimum cost and use it as the planned production volume of each product on the production line. The minimum cost of the production line is calculated based on the production line reorganization cost and the product detention cost.

[0012] In one embodiment, selecting a product on the production line as a representative and calculating the planned production volume and cycle time of the production line includes:

[0013] Select a product on the production line as a representative product, and calculate the conversion coefficients of different products according to the ratio of the time quotas between other products and the representative product.

[0014] Calculate the planned production volume of the production line based on the planned production volume of the representative product and the product of the planned production volumes of other products and the associated conversion coefficients.

[0015] Calculate the production line cycle time based on the planned production volume of the production line and the planned time.

[0016] In one embodiment, before allocating operation elements based on precedence constraints and time constraints, it further includes:

[0017] Decompose the product processing process into operation elements, and compile an operation element matrix according to the sequence relationship of the operation elements.

[0018] Calculate the rank of each operation element according to the operation element matrix and the time vector of the operation element.

[0019] In one embodiment, the precedence constraint is the order of operation element ranks, and the time constraint is the time vector of the operation element.

[0020] In one embodiment, before making the operation time of the working area as close as possible to the production line beat, it further includes:

[0021] Construct and merge the operation element relationship diagram so that the same operation elements of different products are assigned to the same working area.

[0022] In one embodiment, the calculating the actual number of working areas includes:

[0023] Calculate the load of operation elements according to the planned batch and the operation time of operation elements;

[0024] Convert the minimum number of working areas into the ratio of the planned total load to the planned time;

[0025] Calculate the actual number of working areas according to the planned total load, the planned production volume of products, the time quota and the planned time.

[0026] In one embodiment, the calculating the mixed flow ratio of different products according to the actual number of working areas in combination with the product production batch and the time quota includes:

[0027] Calculate the mixed flow ratio of different products according to the ratio of the sum of the products of the product production batches and the time quotas of different products to the actual number of working areas, in combination with the production line load coefficient.

[0028] In one embodiment, the positioning information of production materials based on the actual number of working areas and the mixed flow ratio of different products includes:

[0029] Based on the actual number of working areas, with the left side of the given space range as the reference starting point, in combination with the mixed flow ratio of different products, calculate the equipment coordinate values and constraint conditions of the production line layout;

[0030] Layout the positioning information of production materials according to the equipment coordinate values and constraint conditions of the production line layout.

[0031] In one embodiment, the equipment coordinate values include the initial values of the equipment and the space range boundary, the length and width of the equipment, the endpoint coordinate values of the equipment, and the spacing between adjacent two equipment.

[0032] The above production line layout method analyzes the characteristics of the multi-variety and variable-batch production mode of the production line within the range of production capacity batch, proposes a production line load balancing algorithm adapted to the market characteristics, so as to balance the production rhythm between products, solve the system load balancing problem. At the same time, based on the production line load balancing algorithm, while dealing with its load balancing, it calculates and determines the number of system working areas and the mixed flow ratio. On the one hand, it solves the rationalization problem of the number of production line working areas and the mixed flow ratio, and at the same time, the obtained results can provide support and reference for subsequent planning, scheduling and control. Finally, based on relevant equipment position parameters, etc., the production line buffer configuration rules are obtained, thus completing the layout of the production line. Combining the customized requirements under the multi-variety, variable-batch and cost constraints faced by production manufacturing, comprehensively considering multiple production factors such as production capacity and production line balance, it solves problems such as production line balance, rationalized mixed flow ratio and buffer configuration in layout design, and realizes the dynamic adjustment of equipment spacing, meeting the physical or logical variability of the production line layout and the requirement of customizable production capacity. Description of the Drawings

[0033] Figure 1 It is one of the flowcharts of the production line layout method of this application;

[0034] Figure 2 It is the second flowchart of the production line layout method of this application;

[0035] Figure 3 It is the third flowchart of the production line layout method of this application;

[0036] Figure 4 It is the fourth flowchart of the production line layout method of this application;

[0037] Figure 5 It is the fifth flowchart of the production line layout method of this application;

[0038] Figure 6 It is a schematic diagram of the relationship between the production line cost and production capacity of this application;

[0039] Figure 7 It is a schematic diagram of the operation element allocation of the production line layout method of this application;

[0040] Figure 8 It is a geometric relationship diagram of the production line equipment within the space range of the production line layout method of this application;

[0041] Figure 9 It is a schematic diagram of the comprehensive relationship of the operation elements of the production line layout method of this application. Detailed Implementation Modes

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the scope of protection of this application.

[0043] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used in the description of this application are only for the purpose of illustration and do not represent the only implementation.

[0044] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first feature is in direct contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature has a lower horizontal height than the second feature.

[0046] Unless otherwise defined, all technical and scientific terms used in the description of this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application are only for the purpose of describing specific implementation manners and are not intended to limit this application. The term "and / or" used in the description of this application includes any and all combinations of one or more of the related listed items.

[0047] As Figure 1 shown, in one embodiment, a production line layout method, the method includes the following steps:

[0048] Step S110: Select a product on the production line as a representative and calculate the planned production volume and cycle time of the production line. The planned production volume of the production line is calculated based on the planned production volumes of various products on the production line and the conversion coefficient, and the conversion coefficient is calculated based on the planned production volume of the product and the time quota.

[0049] Specifically, the production line has the characteristics of a multi-variety and variable-batch production mode. When the cycle times of each process in a process are inconsistent, idle time will be generated in other processes except the bottleneck process. In addition to causing unnecessary man-hour losses, it will also cause a large amount of work-in-process redundancy, and in severe cases, it will cause production interruption. Therefore, in the production line layout design stage, in order to make the production line run smoothly, it is necessary to average the operation times of each process and adjust the operation loads of each process so that the operation times of each process are as close as possible. Currently, the problem of single-variety production line balance can be solved well by the Helgeson-Burney method. Therefore, it is considered to make changes and improvements to it so that it can solve the balance problem of multi-variety and variable-batch variable assembly lines. It is necessary to first balance the load of the production line, that is, balance the planned production volume and cycle time of the production line.

[0050] Step S120: Allocate operation elements based on precedence constraints and time constraints so that the operation time of the work area is as close as possible to the production line cycle time, thereby calculating the actual number of work areas. The operation elements are obtained by decomposing the production line processes.

[0051] Specifically, decompose the production line processes to obtain multiple operation elements. When allocating operation elements, precedence constraints and time constraints need to be considered, that is, the preceding operation elements and operation times, so that the operation time of each work area is close to the production line cycle time. Then delete the allocated operation elements and sort the operation elements.

[0052] Step S130: Calculate the mixed flow ratio of different products based on the actual number of work areas, combined with the production batch of the product and the time quota.

[0053] Step S140: Layout the positioning information of production materials based on the actual number of work areas and the mixed flow ratio of different products, thereby completing the layout of the production line.

[0054] Specifically, within the given space range, based on the above-obtained parameters, calculate the layout plan of the production line, the coordinate values of the equipment, and the positioning information of the production line buffer equipment and other production materials.

[0055] The above production line layout method analyzes the characteristics of the multi-variety and variable-batch production mode of the production line within the range of production capacity batch, proposes a production line load balancing algorithm adapted to market characteristics, so as to balance the beats between products, solve the system load balancing problem. At the same time, based on the production line load balancing algorithm, while dealing with its load balancing, calculate and determine the number of system working areas and the mixed flow ratio. On the one hand, it solves the rationalization problem of the number of production line working areas and the mixed flow ratio, and at the same time the obtained results can provide support and reference for subsequent planning, scheduling and control. Finally, based on relevant equipment position parameters, etc., obtain the production line buffer configuration rules, thus completing the layout of the production line. This method combines the customized needs under the multi-variety, variable-batch and cost constraints faced by production manufacturing, comprehensively considers multiple production factors such as production capacity and production line balance, solves problems such as production line balance, rationalized mixed flow ratio and buffer configuration in layout design, and realizes the dynamic adjustment of equipment spacing, meeting the physical or logical variability of production line layout and the requirement of customizable production capacity.

[0056] In one embodiment, before selecting a product on the production line as a representative and calculating the planned production volume and beat of the production line, it further includes the steps of: obtaining the production batch of the production line at the minimum cost and using it as the planned production volume of each product on the production line. The minimum cost of the production line is calculated based on the production line reorganization cost and the product retention cost.

[0057] Specifically, the production capacity of the production line is customizable. When the production task demanded by the market is issued, it is necessary to determine how much production capacity the production line should have to achieve the economic optimum. If the production line has a high production capacity, the processing time is shortened, the capital turnover is accelerated, and the efficiency is improved. However, a high production capacity is also accompanied by problems such as high construction costs and operation costs, such as FMS. Therefore, in order to seek a balance between the two contradictory aspects and achieve the best economic benefits, it is necessary to study the optimal production capacity of the production line before the production line layout is formed. The two cost factors considered in this embodiment are both for the production line itself. One is the reorganization cost C r for adjusting the production line when changing product varieties, and the other is the in-process product retention and storage cost C z , and the calculation formulas are as follows:

[0058]

[0059]

[0060] H = Z v × ω

[0061] where Q yLet \(Q\) be the production batch for a certain planning period; \(P\) be the daily production quantity of the product; \(R\) be the daily demand quantity of the product; \(H\) be the storage cost per unit of work-in-progress; \(G\) be the annual production program of the system; \(K\) be the cost of each system reorganization and adjustment, which can be calculated according to the labor-hour cost; \(\omega\) be the storage cost rate of work-in-progress; \(Z\) v Unit price of work-in-progress.

[0062] According to the given calculation formulas for reorganization cost and work-in-progress storage cost, the total cost function \(C(Q\) y ) can be expressed as:

[0063]

[0064] where \(\alpha\) and \(\beta\) are the weight values of their respective costs.

[0065] Under the cost constraint conditions, to obtain customized production capacity and functions to meet the changing market demands, the direct problem is to determine the batch problem when the formula (1) is minimized. The obtained batch is the optimal production capacity batch with the minimum cost, denoted as \(Q\). Formula (1) is a unary non-linear function with \(Q\) y as the variable. The minimum value of the function can be obtained by the graphical method, where the relationship between cost and production capacity is as Figure 6 shown.

[0066] According to the graphical analysis, it can be known that the function \(C(Q\) y ) has a minimum value. Using the derivative method for finding extreme values, the first-order and second-order derivatives of \(C(Q\) y ) are calculated respectively, and the following results can be obtained:

[0067]

[0068]

[0069] By analyzing the second-order derivative, it can be obtained that its value must be greater than zero. Thus, it can be known that there exists a \(Q\) y such that the function \(C(Q\) y ) has a minimum value. Let the first-order derivative be equal to zero, and the production batch \(Q\) with the minimum cost can be obtained as:

[0070]

[0071] \(H = Z\) v ×\(\omega\)

[0072] Through the above principle analysis, the production capacity batch value \(Q\) with the minimum cost of the production line can be obtained.

[0073] As Figure 2 shown, in an embodiment, a product on the production line is selected as a representative and the planned production quantity and beat of the production line are calculated, including the following steps:

[0074] Step S111: Select a product on the production line as the representative product, and calculate the conversion coefficients of different products according to the ratio of the time quotas between other products and the representative product.

[0075] Specifically, it is first necessary to analyze the production rhythm of the multi-variety and variable-batch production mode. The rhythm refers to the time interval between two adjacent products produced on the production line. For a single-variety production line, its calculation formula is as follows:

[0076]

[0077] Among them, C is the production line rhythm; T is the effective time in the planning period; Q is the planned output in the planning period, that is, the optimal production capacity batch within a certain range; T0 is the institutional time in the planning period; ε is the effective utilization time coefficient. Since the production line rhythms are different for different product varieties, for the rhythm of a multi-variety variable production line, the typical part representative method is used for calculation based on Equation (3). Select a product with a relatively large output and labor volume and a relatively complex process from the varieties that the production line can produce as the representative of the typical part, calculate its rhythm, and then calculate the rhythms of other products according to the rhythm of the representative product and the conversion coefficient.

[0078] Step S112: Calculate the planned output of the production line according to the product of the planned output of the representative product and the products of the planned outputs of other products and their associated conversion coefficients.

[0079] Suppose there are three products of the same family, namely I, II, and III, and their planned outputs in the planning period are Q I , Q II , Q III ; the single-piece time quota on the production line is T AI , T AII , T AIII . Taking product I as the representative of the typical part, the total output and rhythm of the typical product are converted as follows:

[0080] Q = Q I + Q II ·η1 + Q III ·η2 (4)

[0081]

[0082]

[0083] Step S113: Calculate the production line rhythm according to the planned output of the production line and the planned time.

[0084] As Figure 3 shown, in one embodiment, before allocating the operation elements based on the precedence constraint and the time constraint, the following steps are further included:

[0085] Step S310: Decompose the product processing process into operation elements, and compile an operation element matrix according to the sequence relationship of the operation elements.

[0086] Specifically, process synchronization is the load balancing of the production line. Under the condition of the least number of workstations designed in the assembly line, the loads of each workstation should be made as equal as possible. Decompose each process of the product into operation elements, and use a single-code network diagram to represent the sequence relationship of each operation element. Use small circles to represent each operation element, and the numbers marked on the small circles are the processing times required for the operation elements of this process. Subsequently, compile an operation element matrix R according to the operation element sequence relationship diagram. W The matrix elements satisfy the following rules: All this operation element and its subsequent operation elements are 1, and the rest are 0.

[0087] Step S320: Calculate the rank of each operation element according to the operation element matrix and the time vector of the operation element.

[0088] Specifically, calculate the rank of each operation element. Let the operation time vector of each operation element be τ W , there is:

[0089] τ W =[τ1 τ2 L τ n T

[0090] The rank value vector of each operation element:

[0091] W = R W ·τ W =[w1 w2 L w n T

[0092] Compile an operation element rank order table, list in descending order of rank value, and indicate the immediate predecessor operation element of each operation element. Among them, the precedence constraint is the operation element rank order, and the time constraint is the time vector of the operation element.

[0093] In one embodiment, in order to make the operation time of the work area as close as possible to the production line beat, the previous steps also include: constructing and merging the operation element relationship diagram so that the same operation elements of different products are assigned to the same work area.

[0094] Specifically, since a variable assembly line layout including multiple varieties is constructed, the operation element relationship diagram needs to be merged. The same operations of different varieties are assigned to the same operation area, and the same numbers are taken in the relationship diagram. The products of all varieties are synthesized into a relationship diagram respectively. Taking three products as an example, the principle is as Figure 7 shown.

[0095] As Figure 4 ​​As shown, in one embodiment, calculating the actual number of working areas includes the following steps:

[0096] Step S121, calculating the load of the operation element according to the planned batch and the operation time of the operation element.

[0097] Specifically, the formula for calculating the load of the operation element is as follows:

[0098] L ij = f j λ ij t i (6)

[0099] Where f j is the production scheduled batch during the planned period; t i is the operation time of operation element i.

[0100] Step S122, converting the minimum number of working areas into the ratio of the planned total load to the planned time.

[0101] Specifically, the operation area is composed of certain equipment and floor area, and its minimum number can be converted into the ratio of the total production load during the planned period to the planned period:

[0102]

[0103] Where L is the total operation volume of all products; T c is the planned period time.

[0104] Step S123, calculating the actual number of working areas according to the planned total load, the planned production quantity of products, the time quota and the planned time.

[0105] Specifically, the formula for the production line load coefficient is as follows:

[0106]

[0107]

[0108] Where L is the total operation volume of all products; f i is the planned production quantity of product i during the planned period; T i is the single-piece time quota of product i; T c is the planned period time; N is the actual number of working areas of the production line after balancing.

[0109] In one embodiment, the mixed flow ratio of different products is calculated based on the actual number of working areas in combination with the production batch and time quota of the product, including the steps of: calculating the ratio of the sum of the products of the production batch and time quota of different products to the actual number of working areas, and combining with the line load coefficient to calculate the mixed flow ratio of different products.

[0110] Specifically, the number of working areas obtained through the above steps is N, and the optimal production capacity batch of the production line based on cost is Q. The production line layout requires the production of two kinds of part products of the same family. The production batch of the first product within the planned period is f I , and the time quota is T I , the second batch is f II , and the time quota is T II ; the load coefficient required by the system layout configuration is K r . Under the balance of system load, in order to obtain the batch ratio (mixed flow ratio) of the two products, it can be calculated according to the following formula:

[0111]

[0112]

[0113]

[0114]

[0115] As Figure 5 shown, in one embodiment, the positioning information of production materials is laid out based on the actual number of working areas and the mixed flow ratio of different products, including:

[0116] Step S141, based on the actual number of working areas, taking the left side of the given space range as the reference starting point, and combining with the mixed flow ratio of different products, calculate the equipment coordinate values and constraint conditions of the production line layout.

[0117] Specifically, assume that each row of equipment is in a parallel state, and the shape of the equipment is processed as a rectangle. Each work area is represented by a rectangle, and the work area has the required ideal functions. Taking the left vertex of each equipment shape as the calculation reference point, for the convenience of description, the geometric relationship between the production line equipment within the space range is as Figure 8 shown.

[0118] Among them, d0 represents the initial value of the equipment from the boundary, and this value needs to be obtained based on actual on-site research, and at the same time, the convenience of system layout should also be considered; K mi (i = 1, 2,..., n) represents the width dimension of the equipment; L mi (i = 1, 2,..., n) represents the length dimension of the equipment; M i(i = 1, 2, …, n) represents the i-th device; X i (i = 1, 2, …, n) represents the X-axis coordinate value of the i-th device; d ij (i, j = 1, 2, …, n; and i ≠ j) represents the distance between the i-th device and the j-th device; d Z represents the shortest distance between the last row and the width range; d W represents the shortest distance between the last row and the length range; the dashed part is the specified spatial range, and the method described in this embodiment considers the two-dimensional spatial range composed of the length L and the width K.

[0119] Taking the left side of the range space as the reference starting point, according to the above parameters, the device coordinate values and constraint conditions of the system layout are given, satisfying the formula:

[0120] X i+1 = X i ± L mi ± d ij (i = 1, 2, …N; j = i + 1) (14)

[0121] H i+1 = max(K m1 , K m2 , …, K mi ) × 2 + h (15)

[0122] d w ≥ d c ; d z ≥ d b (16)

[0123]

[0124]

[0125] Among them, d c , d b and h: are specified boundary values; Z T is the number of work-in-process products between adjacent operation sites; L p is the geometric length value of the reference standard part in the same family of products; Q is the production capacity batch value; S is the work area influence coefficient; N is the number of work areas under load balance; t i is the processing time of the i-th work site or process.

[0126] Step S142, layout the positioning information of the production materials according to the device coordinate values and constraint conditions of the production line layout.

[0127] In summary, the production line load balancing method used in this embodiment mainly includes: converting the operation time of operation elements in the Herglotz-Böhni method into operation load, and converting the tact time into the planned period time, such as a shift or a day; introducing a product element conversion matrix to calculate the operation load matrix, while ensuring the precedence constraint and time constraint of processes, so that the operation load and the planned period time of each work area are similar; under the limitation of parameters such as the number of work areas, further converting the layout performance parameters into boundary values or constraint quantities to solve the variable batch mixed flow ratio. This avoids the process of repeated trial and adjustment, can reduce the number of calculations, simplifies the calculation process, and can better meet the design requirements.

[0128] Based on the obtained parameter indicators such as the work area and the mixed flow ratio, when it is necessary to add machine tools or buffer storage areas, it is necessary to further analyze in combination with the addition rules, and the following addition optimization rules are summarized:

[0129] (1) Find the bottleneck process location according to the production tact, and judge whether to add a new configuration or equipment to the bottleneck process.

[0130] (2) If max(t1, t2, …, t N ) is at the head of the system, the system does not need to add a buffer, otherwise it needs to be considered.

[0131] (3) If it needs to be added, judge before the work location of max(t1, t2, …, t N ), and there is no need to consider the buffer problem afterwards.

[0132] (4) During the judgment process, search for the position of the maximum processing time value locally one by one, and compare between adjacent work areas. When Z T is greater than 10 within a certain assumed time range, consider adding or demarcating a buffer storage area.

[0133] (5) During the judgment process, if Z T is less than zero and its absolute value is greater than 10, and the difference between the processing times of two adjacent places is relatively large, it is necessary to consider adding a new configuration or new equipment at the i-th work area or equipment to improve its production capacity.

[0134] (6) The above five rules are used in combination until the iterative search is completed.

[0135] The above production line layout method can comprehensively consider multiple production factors such as production capacity and production line balance at the initial stage of production line design, solve problems such as production line balance, rationalized mixed flow ratio, and buffer configuration in layout design, and in order to adapt to the characteristics of today's manufacturing industry with multiple varieties, variable batches, and rapid response to market customization requirements, it is required that the production system can achieve physical adjustment of the production line or logistics logic adjustment of the production line system according to actual production capacity and other requirements. This method can achieve dynamic adjustment of equipment spacing in production layout, meet the physical or logical variability of production line layout, and the requirement of customizable production capacity.

[0136] According to the implementation steps of the method in this embodiment, the following case is used for calculation to demonstrate the implementation method of this method: A certain enterprise needs to design a production line, assuming adjustments and additions are made on the basis of the original equipment library. It is required to produce two products I and II in the same family. There are three operation elements that are different between product II and product I. Among them, the enterprise working system is calculated based on 8 hours per day, the machine utilization rate is 0.85 - 0.9, and the production program is 30,000 pieces per year. Here, one day is taken as the planning period time, then T c = 60×8 = 480min, and the production batch of products during the planning period is to be determined. The time quota for single-piece production of product I is T I = 59min, the time quota for single-piece production of product II is T II = 56min, the unit price of the typical product is 3000 yuan per piece, and the length of the typical workpiece is 0.65 meters. Apply this production line layout method to design the production line layout.

[0137] According to the above formula, the best production capacity of the production line under the condition of minimum cost is:

[0138]

[0139] Based on the given example data, where the weight values α = β = 0.5 are taken; K is the cost per hour for each worker, calculated at 15 yuan per hour. The supply and marketing ratio is taken as R = 0.8P according to the normal enterprise profit; the in-process inventory storage rate is taken as 9%. Substitute the values into the formula, and the best production capacity Q under cost constraints is obtained, which is approximately 130 pieces per day when rounded.

[0140] Based on the part processing procedures, establish their respective operation elements and comprehensive relationship diagrams, as Figure 9 shown.

[0141] Based on the operation element relationship diagram, calculate the operation load matrix as follows. Among them, the first column P i represents the operation element; t i represents the operation time of each operation element; λ ij represents the conversion coefficient; L ij represents the operation loads of the two products; LT It represents the total operation load; FC represents the preceding operation element; the batch quantity of the first product is f, the second product is g, and f + g = Q.

[0142]

[0143] The rank value of each operation element is calculated according to W = R W ·τ W = [w1 w2... w n T τ is a column vector composed of the operation time values of each operation element. Determine R according to the step rules W , and then obtain W. The calculation results are shown in the following table: W

[0144]

[0145] According to the results calculated by the above matrix, the rank numbers of each operation element can be obtained. Combining with the operation load matrix, arrange the order list of each operation element in descending order of rank number. As shown in the following table, where FC represents the preceding element.

[0146]

[0147]

[0148] According to the obtained order list of operation element ranks, under the premise of satisfying the precedence constraint and the planning period time constraint, allocate for each element, and its operation domain division list is as shown in the following table. Where FC represents the preceding element, and Laod represents the operation domain load rate.

[0149]

[0150]

[0151] Through the above calculations, the operation domain of the production line layout N = 17 can be obtained. The load coefficient takes the value of K r = 92%, and from equations (10) and (12), we can get: The calculated revised batch value of product I is f = 80, and the revised batch value of product II is g = 50. The actual load rate can be calculated by taking the overall average value according to the load rates of each operation domain in Table 2 According to the production cycle calculation formula Taking ε = 0.92 based on actual on-site experience, the production cycle can be obtained

[0152] ​According to the above analysis, the product batch value after load balancing and the actual number of working areas can be obtained. The actual number of working areas is 17. Assuming that the length value of the boundary range is 50 meters and the width is 30 meters, a boundary distance of 2 meters is reserved for both the boundary equipment and the range. According to the system layout configuration analyzed earlier, a parallel-series hybrid structure, that is, a configuration with parallel branches and overall series connection, is adopted. By applying equations (11) to (18) and the optimization rules, the coordinates of the production line layout equipment can be obtained, and the results are shown in the following table.

[0153]

[0154]

[0155] Based on the equipment coordinates calculated from the above table, a production line layout planning diagram is generated. The actual on-site layout is planned for the working areas and the placement of each processing equipment according to the above coordinates. At the same time, it should also be combined with the actual situation, and the layout is adjusted according to on-site experience, etc.

[0156] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0157] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A production line layout method, characterized in that, The method includes: Select a product on the production line as a representative and calculate the planned production volume and tact time of the production line. The planned production volume of the production line is calculated based on the planned production volumes of various products on the production line and the conversion coefficient, and the conversion coefficient is calculated based on the planned production volume of the product and the time quota. Allocate operation elements based on precedence constraints and time constraints to make the operation time of the work area as close as possible to the production line tact time, thereby calculating the actual number of work areas. The operation elements are obtained by decomposing the production line processes. Calculate the mixed-flow ratio of different products based on the actual number of work areas, the production batch of the product, and the time quota. Layout the positioning information of production materials based on the actual number of work areas and the mixed-flow ratio of different products, thereby completing the layout of the production line. Before the step of selecting a product on the production line as a representative and calculating the planned production volume and tact time of the production line, it further includes: Obtain the production batch of the production line at the minimum cost and use it as the planned production volume of each product on the production line. The minimum cost of the production line is calculated based on the production line reorganization cost and the product retention cost. The step of selecting a product on the production line as a representative and calculating the planned production volume and tact time of the production line includes: Select a product on the production line as the representative product and calculate the conversion coefficients of different products based on the ratio of the time quotas between other products and the representative product. Calculate the planned production volume of the production line based on the planned production volume of the representative product and the products of the planned production volumes of other products and the associated conversion coefficients. Calculate the production line tact time based on the planned production volume of the production line and the planned time. Before the step of allocating operation elements based on precedence constraints and time constraints, it further includes: Decompose the product processing process into operation elements and compile an operation element matrix according to the precedence relationship of the operation elements. Calculate the rank of each operation element based on the operation element matrix and the time vector of the operation element.

2. The production line layout method according to claim 1, characterized in that The precedence constraint is the order of operation element ranks, and the time constraint is the time vector of the operation element.

3. The production line layout method according to claim 2, wherein Before the step of making the operation time of the work area as close as possible to the production line tact time, it further includes: Construct and merge the operation element relationship diagram to allocate the same operation elements of different products to the same work area.

4. The production line layout method according to claim 3, wherein The step of calculating the actual number of work areas includes: Calculate the load of the operation element based on the planned batch and the operation time of the operation element. Convert the minimum number of work areas into the ratio of the planned total load to the planned time. Calculate the actual number of work areas based on the planned total load, the planned production volume of the product, the time quota, and the planned time.

5. The production line layout method according to claim 4, wherein The step of calculating the mixed-flow ratio of different products based on the actual number of work areas, the production batch of the product, and the time quota includes: Calculate the mixed-flow ratio of different products based on the ratio of the sum of the products of the production batches and the time quotas of different products to the actual number of work areas, combined with the production line load coefficient.

6. The production line layout method according to claim 5, wherein The step of laying out the positioning information of production materials based on the actual number of work areas and the mixed-flow ratio of different products includes: Based on the actual number of work areas, take the left side of the given space range as the reference starting point within the given space range, and calculate the equipment coordinate values and constraint conditions of the production line layout in combination with the mixed-flow ratio of different products. Lay out the positioning information of production materials according to the equipment coordinate values and constraint conditions of the production line layout.

7. The production line layout method according to claim 6, characterized in that The equipment coordinate values include the initial values of the equipment and the boundaries of the space range, the length and width of the equipment, the endpoint coordinate values of the equipment, and the spacing between two adjacent pieces of equipment.

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