JPH0754879B2 - Printed circuit board assembly production method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a printed circuit board assembly production in which components are automatically mounted to assemble a printed circuit board, and in particular, an improvement in a load balance rate that represents a degree of equalization of work loads. And a method for assembling and producing a printed circuit board, which is suitable for reducing the number of setups of parts.

[Background of the Invention]

The conventional method is, for example, the magazine "Electronic Technology", Vol. 24, No. 9
No. 52, pp. 57-57, "Automatic mounting for high-mix low-volume production", a method of fixing a large number of parts used on the entire printed circuit board in the automatic insertion machine for a certain period of time,
In addition, for example, magazine IE, July 1980 issue, pages 48 to 56, "Process management based on basic production planning and its Plan-Do-See
As described in “Cycle”, the setup of parts is reduced like a method in which each worker changes the work order of the work to be performed in one day in consideration of setup. However, these methods have not taken into consideration the reduction of parts setup considering the improvement of the load balance rate related to the line operation rate.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printed circuit board assembling production method for improving the load balance ratio and reducing the number of times of component setup in order to solve the above-mentioned problems.

[Outline of Invention]

In the present invention, attention is focused on a process in which component setup frequently occurs, and by reducing the number of component setups that are similar to each other by aggregating similar types of printed circuit boards to be used, it is possible to reduce the load balance rate. By simultaneously selecting different groups, the operating rate of the entire assembly line can be improved.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. With reference to FIG. 1, the operation when the present invention is carried out in the production workplace will be specifically described. In FIG. 1, 1 is a printed circuit board warehouse, 2 is a transfer line, 3 is an automatic insertion machine, 4
Is an electronic parts warehouse, 5 is an insertion electronic parts supply unit, 6 is a finished goods warehouse, 7 is a controller, and 8 is a host controller. In the figure, a controller 7 controls a printed circuit board warehouse for storing various printed circuit boards 1, an automatic inserter 3 for inserting electronic components into the printed circuit boards, and an electronic component warehouse 4 for storing various electronic components. Are managed and controlled by the host controller 8. There may be a case where centralized control is performed only by the host controller 8 without using these controllers 7. Based on the production plan (production model, production period, quantity, etc.) given from the host controller 8, the controller 7 calculates the optimum injection group of the components to be inserted within a fixed period by the procedure shown in FIG. The result is used as a work instruction. Based on this work instruction, necessary parts are put out from the parts group stored in the electronic parts warehouse 4 and set in the inserted electronic parts supply section 5, and necessary boards are put out from the printed board warehouse 1 and transferred on the transfer line 2. It is conveyed to the automatic insertion machine 3 for insertion. The inserted board is stored in the finished product warehouse 6.

In the above embodiments, the case where the transfer line is one flow shop type has been described, but the present invention is also applicable to the case where the entire automatic insertion machine is one workstation. FIG. 2 is a list of used component types a to n of the printed circuit board shown as an example for explaining the present invention. If there is a limit to the number of parts that can be set in the automatic inserter 3, refer to Fig. 2 (a) and set the printed circuit boards to P ₁ , P ₂ ,
When assembled in P _3, P _4, the order of P _5, the parts set number (maximum section number varieties settable at a time inserted electronic component feeding unit of the automatic insertion machine) and 8, stop automatic insertion machines, automatic The component setup process (hereinafter referred to as "component setup") in which used components are newly set in the inserted electronic component supply section of the insertion machine is
You need 4 times. Therefore, as shown in FIG. 2 (b), by consolidating substrates having similar types of components,
By making P ₂ and P ₅ into one group and the substrates P ₁ , P ₃ and P ₄ into one group, the component setup can be done only twice.

Here, the Hamming distance is an index showing how different two things are in order to express the similarity of the used parts of each printed circuit board, and the Hamming distance H _PiPj of the printed circuit boards Pi and Pj is _expressed by the following equation. Given.

H _PiPj = | P _I ∪P _J −P _I ∩P _J │where P _{I is} a set of used component types of the substrate P _i , and P _{J is} a set of used component types of the substrate P _j . For example, in the example of FIG. 2 (a), the set of used component types of the substrate P ₁ is P1 = {a, e, f, h, k, m}, and the set of used component types of the substrate P ₄ is P4 = It becomes {a, h, k, l, n}.

P _I ∪ P _J and P _I ∩ P _J represent a union set and a common set, and P1 ∪ P4 ＝
{A, e, f, h, k, l, m, n}, P1∩P4 = {a, h, k}. Also, | P _I | represents the number of elements of the set P _I , for example, | P1 |
= 6. That is, the Hamming distance H _PiPj is the number of component types used only on one of the printed circuit boards P _i and P _j ,
The larger this is, the more different the types of parts used in the two printed boards P _i and P _j in terms of part setup.

Further, the boards having a small Hamming distance have a high degree of similarity in component configuration. From this, substrates with a large Hamming distance do not belong to the same group, and conversely, substrates with a small Hamming distance are in the same group, the number of substrates belonging to that group increases, and as a result, The number of groups can be reduced.

FIG. 3 is a flowchart showing a processing procedure for creating an assembly group. First, in step 1, the number of parts that can be set in the automatic insertion machine 3, that is, the maximum number of parts that can be mounted, the number of designated groups, and the group number NGROP = 0 are set. When all the printed circuit boards can be grouped in step 2, the process is completed. If not, that is, if there is an unallocated printed circuit board, go to step 3. In step 3, printed boards having similar types of components are aggregated using the Hamming distance described above within the designated number of groups, and groups are created within the maximum mountable number. In step 4, the load balance rates of the groups obtained in step 3 are obtained.

Here, the evaluation function for obtaining the load balance rate is shown in the following formula.

However, BL _j : Load balance rate of j-th group N: Total number of work steps of printed circuit board assembly line where different automatic insertion machines are installed, or total number of work equipment MP _j : Multiple steps of j-th group , Or in the facility,
The process with the maximum work load, or the work time of the equipment t _jk is the work time in the k-th process of the j-th group. For example, in an assembly line in which five automatic inserters (N) are installed, the work time t _jk of each automatic inserter is t _j1 = 100 minutes, t _j2 = 120 minutes, t _j3 = 150 minutes, t _j4 = 80
Min, t _j5 = 100 minutes, MP _j = t _j3 = 150 minutes, and the load balance ratio BL _j is Becomes

The load balance ratio can be optimized by maximizing the value of the above equation.

Next, in step 5, the group number NGROP is updated. In step 6, the best group among the load balance ratios of each group obtained in step 4, that is,
Select the one with the largest load balance ratio value and register it as the NGROP group. Step 6 in Step 7
The printed circuit boards that belong to the group registered in step 3 are removed from the unallocated boards, and the process returns to step 2. Hereinafter, similarly, groups with the best load balance ratios are sequentially created and registered for unallocated boards, and all boards are grouped. Then, based on the board grouping data obtained as described above and the data of the type of parts used for those boards, the assembly of the printed board is executed by the production line of FIG. In addition, in the description of the present embodiment, the embodiment of the automatic insertion machine that automatically inserts an electronic component having a lead has been described, but it is clear that the same invention can be implemented in an automatic mounting machine that automatically mounts a chip component. is there.

[Effects of the Invention] According to the present invention, in printed circuit board assembly production, not only the number of times of component setup can be reduced, but also the load balance rate, which indicates the degree of equalization of the work load, can be improved. The operation is effective in improving the operation rate of the entire line.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for specifically explaining the present invention, FIG. 2 is a diagram for explaining a method of integrating printed circuit boards for reducing setup of parts, and FIG. 6 is a flowchart showing a processing procedure for creating an assembly group according to FIG. 1: printed circuit board Warehouse 2: conveying line 3: automatic insertion machine 4: Electronic parts warehouse 5: inserting the electronic component feeding unit 6: Completed Warehouse 7,8: Controller P ₁ to P _5: PCB a to n: Using section Variety

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoshi Taise, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Hitachi, Ltd. Institute of Industrial Science (56) References JP-A-60-14976 (JP, A) Kai 60-80299 (JP, A)

Claims (2)

[Claims] 1. A printed circuit board assembling production method for mounting electronic components on a printed circuit board by an automatic mounting machine, wherein a component stage is provided within a range of the number of types of components that can be loaded at a time in a component selection and supply section of the automatic mounting machine. Create one assembly group consisting of printed circuit boards of different models that have a high degree of commonality of parts that can be continuously manufactured without replacement, and for each created assembly group, the degree of equalization of the work load. The load balance ratio is calculated, the assembly group with the best load balance ratio is selected and registered, the printed circuit boards belonging to the selected assembly group are excluded as the distributed printed circuit boards, and the remaining unallocated print For the board, the assembly group is created again, and the subsequent processing is repeated until the remaining unallocated printed board is exhausted. Put into the dynamic mounting machine, the printed circuit board assembly production method reduces component setup number of times and determining the sequence of assembling a group of printed circuit board. 2. A type of component to be mounted on any one of the various printed boards to be assembled in the creation of the assembly group, and a component to be mounted on another one of the printed boards. 2. The method of assembling and manufacturing a printed circuit board according to claim 1, wherein the assembly group is created by evaluating the degree of commonality with the type of hamming with Hamming distance as an evaluation scale.