JPH0770863B2 - How to determine the mounting direction of parts - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining a component insertion direction when a component is inserted into a printed board by an automatic component insertion machine.

[Background of the Invention]

In the printed board assembly that inserts electronic parts into the printed board,
Automatic insertion machines are becoming more popular. This assembly work is performed efficiently, the work time is shortened, the manual work is reduced, and further,
In order to improve product quality, it is important to reduce the number of parts manually inserted by an operator and increase the ratio of parts to be inserted by an automatic insertion machine (automatic insertion rate). In order to improve the automatic insertion rate, we have developed a deformed parts insertion machine that allows automatic insertion of parts with complicated shapes and reduced the number of retrofit parts. In addition, we devised the insertion order and insertion direction of parts. By doing so, the automatic insertion rate can be improved. FIG. 10 (a) shows the interference between the component and the inserter head, but consider the case where the inserter head 102 inserts the component i with the component j already inserted in the printed board 101. Then, since the area (insertion work space) required by the inserter head 102 for automatically inserting the component j is not secured, interference occurs and it is impossible to automatically insert the component i. Such a relationship has been increasing along with the demand for higher density mounting of electronic components on a printed board as electronic equipment products have become smaller and lighter. As a method of avoiding such interference, there is a method of devising the insertion order such as inserting the component j after inserting the component i, but inserting the component by rotating the insertion direction by 180 °. According to
In some cases interference can be avoided. FIG. 10 (b) shows the positional relationship between the inserter head and the parts at that time, but there is no interference and the part i can be automatically inserted. This is because the insertion work space at the time of component insertion is asymmetric with respect to the component axis, and the insertion work space changes by changing the insertion direction. Many of the recent automatic inserters can insert parts from four directions by rotating the table or inserter head, and non-polar parts can be mounted even if the insert direction is rotated 180 °. . Further, even with polar components such as ICs and capacitors, if the component supply direction during component supply is changed, the component can be mounted in the correct direction even if the insertion direction is rotated 180 °.

From the above, it is understood that if the insertion direction of the component is devised, the interference can be avoided and the automatic insertion rate can be improved.

However, conventionally, as described in Japanese Patent Laid-Open No. 60-7200, a method of determining the insertion order based on the external dimensions and height of parts has been discussed, but the insertion direction is changed from the viewpoint of improving the automatic insertion rate. No mention is made of how to decide. In addition, the method of deciding the insertion direction by trial and error takes a lot of time for a board with more than 500 parts to be inserted,
In addition, it cannot be guaranteed that a solution that maximizes the automatic insertion rate will be obtained.

[Object of the Invention]

An object of the present invention is to increase the usage rate of an automatic insertion machine that automatically inserts electronic components with leads on a printed board or an automatic mounting machine that automatically mounts chip components, and mount components that maximize the automatic mounting rate. Since there is interference in deciding the direction or in automatic mounting, there is a method to quickly determine the mounting direction of components that minimizes the total cost of components to be mounted manually without the drawbacks of the conventional technology. To provide.

[Outline of Invention]

The present invention determines the interference between the inserter head and the component when each component is inserted in all the insertable directions, and uses this to determine the component group so that the component does not participate in the interference. , The insertion direction is determined one after another. Since the insertion direction is determined by considering all the insertion directions of the respective parts and checking any possible interference, it is possible to determine the insertion direction of the part having the maximum automatic insertion rate.

Example of Invention

Hereinafter, the present invention will be described based on an embodiment of an automatic insertion machine. Consider the case of using IC inserter and RC (resistor, capacitor, etc.) inserter in this order to insert 15 parts from parts. FIG. 2 shows a process (machine) in which each component can be inserted without considering interference, and an inserting direction. The insertable direction in Fig. 2 is one direction rotated by a certain angle with respect to the coordinate axis defined on the surface of the printed circuit board.
It is defined as the direction of I, III, and IV. The insertion process can be determined by the type of parts such as IC coaxial and vertical mold. Also,
Depending on the polarity of the components and components that can be inserted from only one direction, the component supply direction, and the insertable direction of the inserter, there are those that can be inserted from two directions, including the 180 ° rotated direction. is there. Therefore, it becomes a problem to select one of the insertion directions of the components that can be inserted from the two directions so that the automatic insertion rate is maximized.

However, in order to actually solve the problem, it is necessary to consider all combinations of the parts having two insertion directions. For example, if 50 parts can be inserted from two directions, the number of combinations is 2 ⁵⁰ = 1.13 × 10 ¹⁵ , which is impossible to calculate. It is also necessary to consider the order of inserting the parts.

So that you can consider the insertion direction and the insertion order at the same time,
A constraint condition regarding an insertion order for avoiding interference is obtained for each insertable direction of each component. The process for obtaining this is called an interference check, and is performed as follows. For each part, when it is automatically inserted, interference with all parts that may have been already inserted is determined. For example, in the example of FIG. 2, the parts are the parts,
It is only necessary to look for interference with and the part needs to look for interference with all other parts.

There are several possible methods for determining interference, but as an example, the method for determining interference can be done by checking the overlap between the insertion work space required by the inserter head when inserting a part and the area where other parts exist. Think If the shapes of the inserter heads and parts are created in advance, they can be calculated.

If the inserter head interferes with the part j when the part i is inserted, the part i must be inserted before the part j is inserted. This will be called an insertion work precedence relationship. If there are multiple directions in which parts can be inserted, check for interference in each case. When interference occurs only in a certain insertion direction, enter the insertion direction on the arrow and the insertion work precedence relationship is, for example, It is expressed as. This is because interference occurs when the part i is inserted in the insertion direction II when the part j is present. Therefore, when the part i is inserted in the insertion direction II, the part i must be inserted before the part j. It means that it will not happen.

In this way, when all interference checks have been completed,
This is represented by a directed graph in which parts are vertices and insertion work precedence relationships are represented by edges (FIG. 3). here, When an insertion work precedence relationship occurs between parts using different insertion machines, as described above, in order to add a condition regarding the order in which the insertion machine is used, the reverse insertion work precedence relationship, parts → parts, I think it will occur.

Furthermore, in order to reduce the scale of the problem, the idea of the strongly connected part in graph theory is used. A strongly connected part is a set of vertices that can be reached by tracing edges in a directed graph. When the strongly connected parts of the directed graph created from the insertion work precedence relations obtained earlier are found, it is confirmed that each strongly connected part is a group of parts involved in mutual interference. Therefore, if the algorithm for obtaining the strongly connected portion is used, the component group involved in the occurrence of interference can be easily found.
Using this idea, the number of combinations that must be calculated can be greatly reduced.

Since the existence of the strongly connected portion means the possibility of interference, in order to avoid the interference, the strongly connected portion must be eliminated. To do so, either removal of the insertion work precedence relationship or removal of the parts is required. This is to select the insertion direction of the parts that can take multiple insertion directions, change the insertion process of the parts (automatic insertion → manual operation). Insertion). Therefore, the automatic insertion rate can be maximized by determining the insertion direction so that the number of the insertion process change parts becomes smaller.

Based on the above preparations, the insertion direction of the component having the maximum automatic insertion rate is determined by the procedure shown in FIG.

1) Step 1 The strongly connected part is calculated, and the component group involved in the interference is obtained.

2) Step 2 As for the insertion direction of the parts not included in the strongly connected part, any direction in which the parts can be inserted can be selected. Eliminate these parts and associated insertion work advance (reduce problem).

3) Step 3 For all parts that have insertable directions other than the insertion direction of the insertion work precedence relation, select an insertion direction other than the insertion direction of the insertion work precedence relation to avoid the possibility of interference. Remove the part for which the insertion direction was determined and the insertion work precedence relationship related to that part.

4) Step 4 When there is a part whose insertion direction is determined in Step 3, return to Step 1. If there is no component for which the insertion direction has been determined, the operation proceeds to step 5.

5) Step 5 The insertion direction of the remaining parts must be determined in consideration of the mutual relationship. If the number of parts is small, consider all combinations of the insertion directions of each part, find a solution that maximizes the automatic insertion rate among them, and find the insertion direction of each part. Further, even when the number of parts is large, it is possible to find a solution in a short time by using a method such as the “branch limiting method” in the combination problem.

After the insertion direction of each component is determined in this way, the insertion work precedence relationship related to the determined insertion direction of each component is restored. The insertion order is determined so as to satisfy all the insertion work preceding relationships.

Next, the procedure for determining the insertion direction will be described according to an example. Third
From the figure, by performing the calculation of step 1, a group of parts (strongly connected parts) involved in two interferences, {,},
{,,,,,} are obtained (Fig. 4). Parts that are not included in the strongly connected part in step 2 ...
Determine the insertion direction of ,,,. Since the parts for which the insertion direction has been determined and the insertion work precedence relationship related to those parts are removed, the directed graph is as shown in FIG. In the processing of step 3, the part is inserted in the insertion direction II I.
Since it can be inserted with V and the insertion work precedence relationship is only the insertion direction IV, the insertion direction of the part is determined to be II. Similarly, the part insertion direction is also set to II. The parts and the insertion work precedence relations related thereto are removed (6th
Figure).

Returning again to step 1, the strongly connected part is calculated. The strongly connected part becomes {,,,}, and the insertion direction of the component is determined as an arbitrary insertable direction in step 2 (FIG. 7).

Step 1 is performed again, but the strongly connected portion does not change.
Therefore, in step 5, the insertion direction of the component that maximizes the automatic insertion rate is obtained. In the case of this example, since the component can take only the insertion direction I and the component can take only the insertion direction II, the components and the insertion directions of the components are inevitably determined. Since parts and parts can be inserted in either of the insertion directions I and III, four combinations shown in FIG. 8 must be considered.
In the case of (a), (b), and (c) in FIG. 8, at least two parts must be manually inserted, but (d)
In the case of, if only the parts are manually inserted, the strongly connected portion can be eliminated, and the optimum solution is obtained.

FIG. 9 shows the insertion direction of each component obtained by this method, and the insertion workability precedence relationship that must be observed when the insertion order is determined.

Since this method considers combinations of all directions in which each part can be inserted, a solution that achieves the maximum automatic insertion rate can be obtained. Also, the size of the problem can be reduced by calculating the strongly connected parts and reducing the problem,
Can be calculated in a short time.

In this explanation, the maximum automatic insertion rate is the target function,
Since the cost that increases by manual insertion differs for each part, it is possible to consider giving a cost to each part and minimizing the sum of the costs of the parts that are manually inserted as a purpose function. In the present invention, the embodiment of the automatic inserter for automatically inserting the electronic component with the lead has been described, but it is clear that the same invention can be implemented in the automatic mounter for automatically mounting the chip component.

〔The invention's effect〕

According to the present invention, since there is no interference and the insertion direction of the components that maximizes the automatic insertion rate can be determined, it is possible to minimize the number of manually inserted components that requires more work time than the automatic insertion, and to print. It is possible to reduce the total work time for mounting the components on the board. Further, since this determination can be obtained by a computer in a short time, the NC data of the inserter can be created in a shorter time than the method manually performed in the past. As described above, the present invention has a great effect on both the reduction of the work man-hour and the reduction of the preparation work man-hour of NC data creation.

[Brief description of drawings]

FIG. 1 is a flow chart showing one embodiment of the insertion direction determining method according to the present invention, and FIG.
FIG. 3 is a diagram showing an example of an insertable direction, FIG. 3 is a diagram showing an example of a directed graph of an insertion work precedence relationship, and FIGS. 4 to 8 show changes in the directed graph during an insertion direction determination procedure. FIG. 9 and FIG. 9 are diagrams showing the optimum solution of the example, and FIG. 10 is a diagram for explaining the interference between the parts and the inserter head. 101 …… Printed board 102 …… Insertion machine head i, j …… Parts

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Kobayashi, Inventor Hideaki Kobayashi, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Inside the Institute of Industrial Science, Hitachi, Ltd. (56) Reference JP-A-60-7200 (JP, A) Actual Kai 58-160733 (JP, U)

Claims (2)

[Claims] 1. When mounting a component on a substrate by an automatic component mounting machine, the presence or absence of polarity of the component, or the component supply direction,
Or, which mounting direction is used when there are multiple mounting directions for the component with respect to the coordinate axes defined on the board surface, depending on how the mounting machine head grips the component or whether the mounting machine head or the board can rotate. The mounting work space required by the mounting machine head on the board and other parts on the board when mounting in each mounting direction that can be mounted by the automatic mounting machine for each component. Judging each interference with the space occupied at the time of mounting, obtain the constraint condition expressed by the directed graph regarding the mounting sequence between the components so that the interference does not occur, and from the constraint condition, the component group involved in the occurrence of the interference is determined. , From the idea of the strongly connected part of the directed graph, for the components other than the component group involved in the occurrence of the interference obtained above, select any mountable direction, and If each part into account and removed from the subject, is involved in occurrence of interference mentioned above is, has a direction that can be implemented in addition to mounting direction in the above constraints,
In order to avoid the possibility of interference, the mounting direction is selected, the component is removed from the objects to be considered later, and in the previous step, at least one of the components involved in the occurrence of the interference avoids the possibility of interference. If the mounting direction to be selected can be selected, the steps after the step of obtaining the group of components involved in the occurrence of the interference are repeated in the remaining target components, and if the components involved in the occurrence of the interference are 1 in the previous step. If there is no problem, proceed to the following steps, and finally regarding the parts involved in the occurrence of interference,
A method for determining the mounting direction of each component, wherein the mounting direction of each component is determined so that the number of components that cannot be automatically mounted due to interference is minimized from among the combinations of the mounting directions of each component. 2. From the combination of the mounting directions of the respective components, which is the final step described in claim 1, the number of components that cannot be automatically mounted due to interference is minimized. For the components that are responsible for determining the mounting direction and ultimately causing the remaining interference,
From the combination of mounting directions of each component, the mounting direction of each component is determined so that the sum of the costs of manually mounting the components that cannot be automatically mounted due to interference is determined. Direction determination method.