JP2008234176A - Design supporting method of manufacturing line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a design supporting technology that has high stability to fluctuation, failure or the like of a production tact, and can easily design the manufacturing line capable of reducing the production cost. <P>SOLUTION: This design supporting method of the manufacturing line for performing a determined work to the products with a plurality of automatic machines while the products are sequentially conveyed onto a conveyance road comprises a model creating process (Step S102) of creating a plurality of manufacturing line models where the layout of the plurality of automatic machines is changed, a model selecting process (Step S103) of selecting a specific manufacturing line model by the operation simulation based on the production tact of each created manufacturing line model, an evaluating process (Step S104) of performing quality engineering evaluation to the specified manufacturing line model based on the index showing at least production tact, the failure rate for each automatic machine, and the stability of working hour, a condition setting process (Step S105) of setting the operation condition of each automatic machine based on the evaluation result. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a design support technology for a production line.

  When designing a production line having a plurality of manufacturing processes, a plurality of engineers often design each process independently. For this reason, if the information held by each engineer is different, each process is designed based on the information held for each engineer, so there are many points to be corrected when each process is connected, and the design period is prolonged. Cause.

Therefore, Patent Document 1 discloses a technique for designing a production line by creating a virtual model of a production line based on information centrally managed by a computer and performing a simulation.
JP 2003-44115 A

  In the technique disclosed in Patent Document 1, each process of the production line is designed based on information centrally managed by a computer, so that the number of corrections can be reduced as a whole production line, and the design period is shortened. can do.

  However, in designing a production line, it is important not only to shorten the design period, but also to be able to design a production line that satisfies the planned production tact and is highly stable with respect to production tact fluctuations and failures. Further, when the designed production line has excessive functions, the cost is increased as a result.

  Therefore, an object of the present invention is to realize a design support technology that can easily design a production line that has high stability against fluctuations in production tact, failure, and the like and can reduce production costs.

  In order to solve the above-described problems and achieve the object, in the invention according to claim 1, a manufacturing line design support method for performing a predetermined operation on a product by a plurality of automatic machines while sequentially transporting the product on a transport path A specific production line model is selected by a model creation process for creating a plurality of production line models in which the layout of the plurality of automatic machines is changed and an operation simulation based on the production tact of each created production line model. A model selection step, and an evaluation step for performing a quality engineering evaluation on the identified production line model based on an index indicating at least the production tact and the failure rate and working time stability for each automatic machine, And a condition setting step for setting operating conditions for each automatic machine based on the evaluation result. Support method is provided.

  According to the first aspect of the present invention, it is possible to easily design a production line that is highly stable against fluctuations in production tact, failure, etc., and can reduce production costs.

  In the invention which concerns on Claim 2, you may set the number of pending | holding products before and behind the said automatic machine further in the said condition setting process. According to this configuration, the number of pending products before and after the automatic machine can be set appropriately.

  In the invention according to claim 3, the production line is an engine assembly line of an automobile, and the automatic machine includes a fastening device for fastening parts to the engine and an oil leak that detects the presence or absence of oil leak from the engine. And a detection device. According to this configuration, even if the production line is an automobile engine assembly line, the same effects as described above can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the design assistance technique which can design easily the manufacturing line which has high stability with respect to the fluctuation | variation of production tact, a failure, etc. and can reduce production cost is realizable.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The embodiment described below is an example as means for realizing the present invention, and the present invention can be applied to a modified or modified embodiment described below without departing from the spirit of the present invention.

  In addition, a storage medium storing a computer program for executing processing corresponding to an embodiment to be described later is supplied to the computer main body, and the computer main body reads the program code stored in the storage medium to perform the above processing. You may make it perform.

  FIG. 1 is a block diagram showing a functional configuration of a design support system according to an embodiment of the present invention. The design support system includes an input unit 10, a control / calculation unit 20, and an output unit 30.

  Interfaces such as a keyboard 11 and a mouse 12 are connected to the input unit 10, and the user can perform various input operations through these interfaces. The input unit 10 receives layout information 13 related to the arrangement of equipment and workers on the production line. In addition, process capability information such as production plan information 14 related to the production plan, working time required for each equipment, failure rate indicating the rate of equipment failure, and recovery time required for recovery when equipment failure occurs. 15 is input.

  Note that these pieces of input information may be input by the user as needed, or information stored in advance in the computer may be used. Moreover, it is good also as a structure which acquires the information updated at any time from the server connected to the network.

  In the control / calculation unit 20, an operation simulation is performed as the CAE analysis 21 based on the information input by the input unit 10. Here, the production volume (production quantity) for each production tact, the production quantity (production quantity) for each production line model, the factor effect indicated by the SN ratio and sensitivity, and the optimum factor level set as the production plan information 14 in the input unit 10 are as follows. Calculated.

  Here, a method for evaluating a production line based on the SN ratio and sensitivity is a method generally used in the field of quality engineering. The S / N ratio is an index indicating the ratio between the signal factor S and the error factor N. A large S / N ratio can be said to be a stable production line with little variation. Sensitivity is an index indicating a difference from a target value, and it can be said that a low sensitivity is close to an optimum condition. In addition, when evaluation of SN ratio differs from evaluation of sensitivity, priority is given to evaluation of SN ratio.

  A display 31 is connected to the output unit 30, and the operation simulation result in the control / calculation unit 20 is output on the display 31. The output information is set based on dynamic characteristic information 32 indicating the balance of the production line, information 33 indicating the volume for each operation rate, factor effect information 34 indicating the evaluation result based on the SN ratio and sensitivity, and factor effect information 34. And the optimum factor level 35 and the like.

  FIG. 2 is a flowchart showing an operation procedure of the design support system according to the embodiment of the present invention. First, various parameters are input via the input unit 10 (step S101). Based on this input information, the control / calculation unit 20 creates a plurality of production line models in which the layouts of the plurality of automatic machines are changed (step S102). Next, a specific production line model is selected by operation simulation in each production tact of each production line model created (step S103). Next, the control / arithmetic unit 20 performs quality engineering evaluation on the specified production line model based on at least the index indicating the production tact, the failure rate for each automatic machine, and the stability of the working time (step) S104). Then, based on the quality engineering evaluation result, the operating condition of each automatic machine is set (step S105). In step S105, the number of pending products before and after the automatic machine is also set. The result obtained by the above processing is output on the display 31 (step S106).

  As an embodiment of the present invention, assuming that the production line is an automobile engine assembly line, the production line layout model creation process, model selection process, evaluation process, and condition setting process will be specifically described. To do.

<Model creation process (step S102)>
In an automobile engine assembly line, a plurality of automatic machine processes (in this embodiment, automatic machine processes A to C) in which an automatic machine performs various processes, and manual processes (in this embodiment) in which an operator performs various manual operations. In the form, it is comprised by manual operation process A thru | or C), and both are arrange | positioned alternately. In this production line, a plurality of automatic machine processes and manual work processes are connected by a conveyance path, and various operations are performed on the engine while the engine is sequentially conveyed on the conveyance path. First, a process (neck process) that greatly affects the operating rate of the production line is selected from a plurality of automatic machine processes and manual processes. There are various methods for this selection. When an abnormality occurs, it is selected based on the time required for recovery (stop / return / quality check), variation in the recovery time, frequency of occurrence of abnormality, etc. The Since the manual work area does not affect the operating rate of the production line, only the automatic machine process is selected.

  3 to 5 are diagrams showing a layout of a production line created by a model creation process according to an embodiment. As shown in FIGS. 3 to 5, the automatic machine process B is a process which is arranged between the manual process B and the manual process C and operates in synchronization with these processes. The automatic machine process B includes a head cover fastening device 110, a crank pulley fastening device 120, and a CPT leak test device 130. The head cover tightening device 110 and the crank pulley tightening device 120 are fastening devices that fasten parts (head cover or crank pulley) to the engine. It has a function to detect whether tightening is performed by value. The CPT leak test apparatus 130 is an oil leak detection apparatus that detects the presence or absence of oil leak from an engine that has been assembled with parts, and supplies pressurized air to the inside to determine whether there is a pressure difference from the master chamber. By detecting this, the presence or absence of oil leakage is detected. The head cover tightening device 110 and the crank pulley tightening device 120 do not require a long recovery time at the time of equipment failure, so the buffer may be small. However, the CPT leak test fastening device 130 has a recovery time at the time of equipment failure Since it takes a long time, it is necessary to set many buffers.

  The difference between the automatic machine process B (model 1) shown in FIG. 3 and the automatic machine process B (model 2) shown in FIG. 4 is based on the number of buffers before and after the CPT leak test apparatus 130. The difference is whether it is set to a letter shape (also referred to as an overhead type, indicated by a broken line 101) or on a straight line (also referred to as a connected type, indicated by a broken line 102). Further, the difference between the model 2 and the automatic machine process B (model 3) shown in FIG. 5 is that the parts container used in the manual process is transported together with the engine in the automatic machine process (set transport system) or the parts container. The difference is whether it is transported by a bypass route that transports only (also referred to as a bypass transport method; indicated by a broken line 103).

<Model selection process (step S103)>
Next, processing for selecting a layout of such a different production line will be described. First, in order to select model 1 or model 2, operation simulation is performed for a plurality of production line models having different numbers of buffers before and after the CPT leak test apparatus 130. FIG. 6 is a diagram illustrating a result of the operation simulation by the model selection process according to the embodiment. The production line models A to C need to be overhead because the number of buffers before and after the CPT leak test apparatus 130 is large, and the production line models D to G have a small number of buffers before and after the CPT leak test apparatus 130. , Can be connected. According to the results shown in FIG. 6, it can be seen that if the number of buffers before and after the CPT leak test apparatus 130 is increased, the output is increased and the number of losses is reduced. However, when the number of buffers is increased, especially when the overhead type is used, the production line becomes longer and costs increase. For this reason, the production line model to be adopted is selected in consideration of the result obtained by the operation simulation, the installation space, the cost, and the like. In this embodiment, the production line model E (model 2) is adopted.

  Next, in order to select the model 2 or the model 3, the production tact is divided into several levels and an operation simulation is performed. In FIG. 7, (a) is an operation simulation result in the bypass conveyance method, and (b) is an operation simulation result in the set conveyance method. 7 (a) and 7 (b), the target value indicates a value when an error factor such as equipment failure does not occur when set for each production tact, and the capability is an actual value considering the error factor. Value. As shown in FIGS. 7 (a) and 7 (b), it can be seen that if the production tact is increased, the capacity approaches the target value, that is, approaches a state in which an error factor such as equipment failure does not occur. Further, comparing the simulation results of both, it can be seen that an error factor is less likely to occur when bypass conveyance is performed than with set conveyance. Therefore, in this embodiment, the model 2 that performs bypass conveyance is adopted.

<Evaluation process (step S104)>
Quality engineering evaluation is performed on the production line model (model 2) specified in this manner based on at least an index indicating the production tact, the failure rate for each automatic machine, and the stability of work time. 8A is a diagram showing control factors of each automatic machine, FIG. 8B is a diagram showing signal factors of each automatic machine, and FIG. 8C is a diagram showing error factors of each automatic machine. As shown in FIG. 8A, for each automatic machine, three levels 1 to 3 are set with the failure rate, work time (cycle time), and the number of buffers before and after the automatic machine as control factors. Further, as shown in FIG. 8B, three levels M1 to M3 are set using the production tact as a signal factor. Further, as shown in FIG. 8C, two stages of error factors N1 and N2 are set for each automatic machine using the failure time as an error factor.

  Based on the control factor, signal factor, and error factor set in this manner, the optimum factor level is verified and evaluated using an L18 orthogonal table that is common in the field of quality engineering. FIG. 9 is a diagram showing an evaluation format using the L18 orthogonal table. In FIG. 10, (a) is a diagram showing the distribution of the SN ratio for each control factor, and (b) is a diagram showing the sensitivity distribution for each control factor. FIG. 10A is for comparing the control factors A to H on the horizontal axis and the SN ratio on the vertical axis, and comparing the SN ratio for each level of each control factor. FIG. 10B is for comparing the sensitivity for each control factor by setting the control factors A to H on the horizontal axis and the sensitivity on the vertical axis.

  The S / N ratio is an index indicating the variation in production, and can be obtained by a mathematical formula (S / N ratio = signal factor / error factor). When the S / N ratio is a high value, it indicates that the error factor is small, so that there is little production variation and stable production can be performed. Therefore, it can be read from FIG. 10A which level is the highest value for each control factor, and each parameter can be set. In FIG. 10A, the highest value is circled. On the other hand, the sensitivity is an index indicating the volume, and it can be said that the higher the value, the higher the productivity. For this reason, as with the S / N ratio, it is possible to read from FIG. 10B which level is the highest value for each control factor and set each parameter. In FIG. 10B, the highest value is circled. However, the level at which the highest value is taken may be different between the SN ratio and the sensitivity. In the present embodiment, the control factors C, E, G, and H are different. In this case, priority is given to the evaluation result in the S / N ratio in order to prioritize suppression of production variations.

<Condition setting process (step S105)>
Next, whether or not the evaluation by the SN ratio may be prioritized by performing an operation simulation with the conditions selected by the evaluation by the SN ratio and the conditions selected by the evaluation by the sensitivity, That is, it is verified whether or not it has robustness (toughness). If it is determined by this verification that the system has robustness, the operating condition of each automatic machine is set based on the evaluation result in the SN ratio.

  According to the present embodiment, it is possible to realize a design support technology that can easily design a production line that has high stability against fluctuations in production tact, failure, and the like and can reduce production costs.

It is a block diagram which shows the function structure of the design support system which concerns on one Embodiment of this invention. It is a flowchart which shows the operation | movement procedure of the design support system which concerns on one Embodiment of this invention. It is a figure which shows the layout of the manufacturing line created by the model creation process which concerns on one Embodiment. It is a figure which shows the layout of the manufacturing line created by the model creation process which concerns on one Embodiment. It is a figure which shows the layout of the manufacturing line created by the model creation process which concerns on one Embodiment. It is a figure which shows the result of the operation simulation by the model selection process which concerns on one Embodiment. (A) is an operation simulation result by a bypass conveyance system, (b) is an operation simulation result by a set conveyance system. (A) is a figure which shows the control factor of each automatic machine, (b) is a figure which shows the signal factor of each automatic machine, (c) is a figure which shows the error factor of each automatic machine. It is a figure which shows the format for evaluation using a L18 orthogonal table. (A) is a figure which shows distribution of S / N ratio for every control factor, (b) is a figure which shows distribution of sensitivity for every control factor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Input part 20 Control and calculating part 30 Output part 110 Head cover fastening apparatus 120 Crank pulley fastening apparatus 130 CPT leak test apparatus

Claims (3)

A production line design support method for performing a predetermined operation on a product by a plurality of automatic machines while sequentially conveying the product on a conveyance path,
A model creation step for creating a plurality of production line models in which the layout of the plurality of automatic machines is changed;
A model selection process for selecting a specific production line model by an operation simulation based on the production tact of each production line model created,
For the identified production line model, an evaluation process for performing quality engineering evaluation based on at least the production tact and an index indicating the failure rate and work time stability for each automatic machine;
Based on the evaluation result, a condition setting step for setting operating conditions of each automatic machine,
A production line design support method characterized by comprising:   2. The production line design support method according to claim 1, wherein in the condition setting step, the number of suspended products before and after the automatic machine is further set.   The production line is an automobile engine assembly line, and the automatic machine includes a fastening device that fastens parts to the engine and an oil leak detection device that detects the presence or absence of oil leak from the engine. The production line design support method according to claim 1.

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