JPH0630010B2 - Electronic component insertion order determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] In the present invention, when a path connecting these points is determined so as to include a large number of points having a constraint condition with respect to some points regarding the passage order, a plurality of points exist. Related to the shortest route determination method for promptly finding the route with the shortest path length among the following routes, especially considering each component insertion position on the printed circuit board as a point, and electronic components on the printed circuit board by the automatic insertion machine. The present invention relates to an electronic component insertion order determination method for optimally determining the insertion order of electronic components so that the sum of the movement distances of the insertion heads during insertion is minimized.

[Background of the Invention]

As a method for determining the shortest route from the routes connecting a large number of points so far, as described in JP-A-59-108106,
Although some methods are known, no consideration is given to the constraint conditions regarding the passage order of points. Also known is the "exhaustive enumeration method (complete enumeration method)," which finds all transit orders and finds the transit order that is the shortest route among those that satisfy the constraint conditions. Has a problem that it exceeds the practical range.

[Object of the Invention]

An object of the present invention is to insert an electronic component on a printed board by an automatic insertion machine even if there is a restriction on the insertion order of the electronic component on the printed board based on a preliminary mutual component interference check. An object of the present invention is to provide an electronic component insertion order determination method for optimally determining the insertion order of electronic components so that the sum of the movement distances of the insertion heads is minimized.

[Outline of Invention]

For this purpose, the present invention, when the insertion position on the printed board of each electronic component is known in advance, after each electronic component is sequentially gripped by the insertion head by the automatic insertion machine,
When sequentially inserting into predetermined insertion positions, each insertion position is regarded as a point, a distance between two points relating to an arbitrary combination is given in advance, and electronic parts are partially inserted. Regarding the order of, the constraint conditions based on the prior mutual interference check between components are given, and the constraint conditions in the component insertion order are satisfied, and the sum of the movement distances of the insertion heads during component insertion is satisfied. Is an electronic component insertion order determination method for determining the insertion order that is the shortest, and each time a specific point is selected from the set of points that satisfy the constraint condition in the insertion order of components, the point is selected. A point that is excluded from the set and that has no constraint condition in the insertion order of parts due to the selection of the point is newly added to the set, and the point closest to the specific point is selected from the new set. To be the next specific point By sequentially repeating that,
From a certain point as a starting point, n (n ≠ 1) points are obtained, and a constraint condition on the insertion order is calculated from the insertion order of all the parts obtained for the n points including the starting point. This is achieved by sequentially selecting the point that is next to the above-mentioned starting point as a new starting point by sequentially selecting the one that is satisfied and has the shortest moving path.

Example of Invention

 The present invention will be described below with reference to FIGS. 1 to 9.

First, the outline of the principle of the present invention will be described with reference to FIGS. 1 and 2. For example, it is assumed that the distance matrix shown in FIG. 2B is given to the points P1 to P5 shown in FIG. 2A. In this case, the distance is not limited to the length of the straight line connecting the two points, and other meanings may be added. For these points, it is assumed that there are constraint conditions (P2 → P5, P2 → P1, P1 → P3) regarding the passage order as shown in FIG. The constraint condition (Pi → Pj) here means that the point Pj can be passed only after passing the point Pi, and it is not always necessary to pass Pi immediately after Pi.

By the way, in this example, the route with the shortest sum of distances is P4
→ P1 → P2 → P3 → P5 and the length of the route is 58, but this route has a constraint condition (P2 →
Since P1) is not satisfied, this cannot be the solution. In the case of this example, the route P2 → P1 → P4 → P
3 → P5 has a route length of 66, and is the shortest route that satisfies the constraint condition.

When the number of points is small as in this example, all routes are found, the one that satisfies the constraint condition is selected, and the route with the shortest route length is selected from the routes that satisfy the constraint condition. The "complete enumeration" can be used, but if the number N of points becomes large, then the route is N! As it exists, it is not a practical method.

In addition, there is a solution for the “traveling salesman problem” as a method for obtaining the shortest route of such many points, but in this case, the constraint condition cannot be expressed.

To explain the present invention in detail, as shown in FIG. 1, a point is represented as a vertex of the graph in consideration of a constraint condition relating to the passage order of points, and a constraint graph → is expressed as a directed graph having an edge as an edge. However, the points that can be selected as the first point at this time are P2 and P4, and P2 is first selected. By selecting P2, the constraint condition of P2 → P1 and P2 → P5 disappears, and P1 and P5 are newly added to the set of points that satisfy the constraint condition of the passage order.
Hereinafter, as shown in the figure, P1, P4, P3, and P5 are selected one after another, and P2 → P1 → P4 → P3 → P5 is obtained as the shortest route among the routes satisfying the constraint condition. Although the optimum solution is obtained in this example, the optimum solution is not always obtained. However, it is possible to obtain a solution close to the optimum solution.

Although the principle of the present invention is basically as described above,
The following methods have been adopted to improve the accuracy of the solution.

That is, a small positive integer n (≠ 1) is taken, n points are selected in the order close to the starting point, and the shortest one satisfying the constraint condition is selected from the passage order of these n continuous points. Then, the next point after the starting point is decided. In this method, if the i-th passing point P (0) is already found, the (i + 1) -th passing point as the next passing point is found as follows.

The point P (1) closest to P (0) is selected from the set of points satisfying the constraint.

The P (1) is removed from the set of points satisfying the constraint condition, and the point without the constraint condition is added to the set of point satisfying the constraint condition by selecting P (1).

From the set of points that satisfy the constraint, select P (2) as the closest point to P (0).

In this way, n points near P (0) are selected.

From P (0) as a starting point, a route satisfying the constraint condition is selected from the passage order of P (1) to P (n), and the shortest route is selected from the routes.

Let P (k) be the second passing point of the shortest path obtained in step 1, that is, the point passing next to P (0), and this is defined as the (i + 1) th passing point.

In this way, by repeating the processes of to one after another, the overall passage order is obtained. By the way, as can be seen from the processing of (1), when n is increased, the number of routes satisfying the constraint condition is increased. Therefore, the value of n is preferably about 8 at the maximum. With this method, it is possible to deal with the case where there are isolated points.

The method for improving the accuracy of the solution has been generally described above. The method will be specifically described below with reference to FIGS. 3 (a) and 3 (b).

That is, assuming that P1 to P9 are passing points, P7 → P2, P6 → P9 are constraint conditions, and n = 4 with P1 as a starting point, the set of points satisfying the constraint condition is {P3 , P4, P5, P6, P7, P8}, of which the point P7 closest to P1 is first selected by referring to the distance matrix shown in FIG. 3 (b). When P7 is removed from the set, P2 is newly added to the set and the set becomes {P2, P3, P4, P5, P8}. Next is P1
The point P2 closest to is selected. In this way, the four points P2, P3, P7 and P8 are selected.
Now, there are 24 routes starting from P1 and passing through these four points, and the shortest route among those satisfying the constraint condition is P1 → P8 → P7 → P2 → P3. Therefore, P8 is defined as the next passing point.

Next, considering a route having P8 as a starting point, the four points selected in this case are P2, P3, P6, and P7, and the shortest route is P8 → P7 → P2 → P3 → P6. Therefore P
P7 is selected as the next passing point of 8. In this way, the path P is obtained by obtaining the passing points one after another.
1 → P8 → P7 → P2 → P3 → P6 → P9 → P5 → P4
Is obtained as shown in FIG. When this is solved by the basic method described above (when n = 1), the route is P1 → P7 → P2 → P3 → P6 → P as shown in FIG.
It turns out that 9 → P5 → P4 → P8, and the method of n = 4 is superior. By the way, in this example, the distance is shortened by 20% or more.

Finally, the above shortest path determination method will be described in the present invention, that is, an electronic component insertion order determination method when mounting electronic components on a printed board. Electronic components are inserted one after another by an automatic insertion machine when mounting on a printed board, but it is said that the total insertion time can be shortened by 10% to 20% by properly selecting the insertion order. By the way, there are constraints as shown in FIG. 6 regarding the order of insertion into the printed board.

That is, when the component I is inserted on the board Q, the insertion head of the inserter (the position of the head is shown by a broken line) does not interfere with the component J, but when the component J is inserted, the component I interferes with the insertion head. It means that the component J cannot be inserted while I is already inserted. In other words, there is a constraint condition regarding the insertion order of component J → component I, and if it is not satisfied, automatic insertion cannot be performed.

Actually, the number of parts mounted on the printed board may exceed 1000 points, and the number of parts to be inserted by one automatic insertion machine
May exceed 300. In such a case, many constraint conditions regarding the insertion order between the two parts occur, and it takes a lot of time for a human to determine the insertion order that shortens the entire insertion work time while considering all of them. ,
Moreover, not only a good solution cannot be obtained, but also an order in which the constraint conditions are not satisfied is determined. Therefore, interference may occur, which may cause not only defective insertion but also damage to parts and heads, and it is necessary to use the method according to the present invention.

First, if the method for determining the constraint condition regarding the insertion order is explained, there are several possible methods for determining this.
One of the simplest of them will be described below.

When the component m is inserted onto the substrate Q by the insertion head P as shown in FIG. 7 (a), the position of the insertion head at the time of insertion is P '. In this case, the already inserted parts k,
When there is l, the part l will interfere with the insertion head P during insertion. As shown in FIG. 7 (b), when the part area of the part m is expressed as M, the part area of the part k is K, the part area of the part l is L, and the insertion work space of the part m is N on the plane. The interference check is performed by checking the overlapping state of these figures K to N. Here, the insertion work space N for the component m and the component l
Since it overlaps with the part region L of, the insertion work precedence relationship (part m → part l) as a constraint condition is obtained. As can be seen from FIG. 7, it is necessary to change the size of the insertion work space N according to the heights of the components located in the periphery thereof. Therefore, first of all, the insertion work space is calculated assuming that the peripheral parts have the maximum height of all the parts, and the overlapping state is checked using this,
If there are overlapping parts, the insertion work space can be corrected to a small value according to the height of the parts, and the overlapping can be checked again.

As mentioned above, as the interference check, the insertion work space and the part area are represented by simple plane figures such as rectangles and circles, and the method of checking the interference by the overlapping state of these figures is described. It is also possible to express it as a combination of circles or the like, or as a three-dimensional solid such as a rectangular parallelepiped or a cylinder, or a combination thereof, and check interference by the overlapping state.

Next, with respect to the case where the component area is a rectangle or a circle, an embodiment of an algorithm of the graphic overlap check will be described. In this example, the overlap check is performed as follows.

That is, when the figures are rectangles, a right-angled region (including the same rectangle) and an upper right point (upper right vertex) defined by both sides intersecting at the lower left point (lower left vertex) with respect to one rectangle as a reference. If there is another rectangle in any of the right-angled regions (including the same rectangle) defined by the intersecting sides, both rectangles shall overlap each other. When the figure is a rectangle and a circle, a region with a width corresponding to the radius of the circle is set around the rectangle, and when the center of the circle exists in this region or in the rectangle, The rectangle and the circle shall overlap each other. Furthermore, when the figures are circles, if the distance between the centers of the circles is less than or equal to the sum of the radii of both circles,
The circles are supposed to overlap each other.

FIG. 8 shows the flow of the insertion work precedence relationship determination (interference check) processing, and the processing contents at each step are as follows.

(step1) Using the part size data in the part information, the part area is obtained for all the inserted parts in the assembly information.

(step2) The insertion work precedence relationship is determined in order for each process,
The target process (target process) is determined from the process sequence designated in advance. When the determination of the insertion work preceding relationship is completed for all the processes, all the processes are completed.

(step3) From all the inserted parts, according to the contents of the insert process data item of the part record in the assembly information, the part to be inserted in the target process (target process insert part) and the process inserted before the target process. And the parts (inserted parts) to be selected.

(step4) The insert work space is calculated for all the target process insert parts.

(step5) Select one component from the target process insertion components. If all parts are selected, go back to step 2.

(step6) Check the overlap between the insertion work space of the selected part and the part area of the inserted part and all target process insertion parts other than the selected part. Here, the range exceeding the board size and the range used by the board holder and the board loader are treated as insertion restriction areas in the same manner as the parts area of the inserted parts.

(step7) After obtaining the insertion work precedence relation from the result of step6 and registering it in the insertion work precedence relation file on the magnetic disk, step
Return to 5.

From the insertion work precedence relationship created in this way, the parts (non-insertable parts) that interfere with each other even if the insertion order is changed are obtained, and this is displayed on the display. Make changes to. This process is also performed for each process, but non-insertable parts occur in the following two cases.

(i) In the case where there is an insertion work precedence relationship of component i → component j, and the insertion process of component j precedes the insertion process of component i.

(ii) Even if the parts are inserted in the same process, for example, there is an insertion work precedence relationship of part i → part j and part j → part i. Even if there are three or more parts, part k → part l, part l
→ When there is an insertion work precedence relationship of part m, part m → part k.

As a countermeasure against such a case, there are a method of changing the inserting step and a method of changing the inserting direction.

When the insertion process is changed, for example, there is an insertion work precedence relationship of part i → part j, and the insertion process of part j is part i.
When the insertion process of the part j is performed before the insertion process of the part i,
If there is a change after the insertion step of, there is an insertion order that satisfies this insertion work precedence relationship. Further, for example, if the inserting process of the part i is changed to the manual assembling process, the inserting work space can be reduced, so that the inserting work precedence relationship of the part i → part j may disappear.

When the insertion direction is changed, for example, when there is an insertion work precedence relationship of part p → part q, and the part p has no polarity, it is possible to rotate the insertion direction of the part p by 180 ° for insertion. As a result, the insertion work space for the component p changes, and thus the insertion work precedence relationship of component p → component q may disappear.

Whichever method is adopted, the entire insertion work precedence relationship changes, so it is necessary to re-execute the stage of the insertion work precedence relationship determination (interference check) shown in FIG.

As a method of obtaining a non-insertable component group that causes interference in the components inserted in the same process from the insertion work precedence relationship created in FIG. 8 in any order,
Below is a solution that applies graph theory.

In this solution, each insertion work (inserted part) is represented by a vertex, and the insertion work precedence relationship is represented by a side (direction of arrow), and the insertion work precedence relationship is represented by a directed graph. FIG. 9 is a directed graph of the insertion work precedence relationship in the present method, in which (a) is an example when there are the insertion work precedence relationships shown in the figure for nine types of parts 11 to 19. . When a strongly connected portion, that is, a set of vertices that can be reached according to edges is obtained on this graph, this becomes one set of non-insertable component groups. For example, the parts 12 to 14 are one non-insertable part group, and these three parts do not have an insertion order that satisfies these insertion work preceding relationships. Similar things, parts
The same can be said for groups of 18,19. Such a non-insertable component group can be easily obtained using a known graph theory.

By changing the insertion process and the insertion direction as described above, all the non-insertable component groups can be excluded and a final insertion work preceding relationship can be created. For example, in FIG. 9 (a), if the insertion process of the component 12 is changed to a later insertion process and the insertion direction of the component 19 is changed, the component 11
→ Parts 12, Parts 12 → Parts 13, Parts 14 → Parts 12, Parts 19 →
Since there is no precedent relationship for the insertion work of the component 18, FIG. 9 (b)
As shown in, it is possible to create a directed graph of a final insertion work precedence relationship in which at least one insertion order exists.

The method of interactively changing the insertion process and changing the insertion direction based on the designer's judgment has been described above. However, this designer's judgment is automated and the insertion process is performed one after another for non-insertable parts (groups). By repeating the change of the insertion direction and the determination of the insertion work precedence relation, the final insertion work precedence relation without the non-insertable component group can be obtained.

Now, when the final insertion work precedence relationship is determined by the change of the insertion process or the insertion direction as described above, there is always an order in which the target process insertion part can be inserted while satisfying these constraint conditions. In the insertion order determining step, the optimum one is obtained from these insertion orders. For example,
Insertion order that minimizes the total sum of the movement distance of the insertion head (movement distance of the XY table of the insertion machine) at the time of insertion (this insertion order is the time required to insert all electronic components on the printed board in a predetermined manner). , Which is an important factor in determining the insertion distance), but if the shortest route determination method described above is applied to this insertion order determination, it is easy to find that the movement distance is almost the shortest. Moreover, it is required promptly. If the insertion process and the insertion order are determined in this manner, the component insertion NC data will be created for each insertion machine according to the determination, which is facilitated by a known technique.

〔The invention's effect〕

As described above, in the case of the present invention, the sum of the movement distances of the insertion heads at the time of inserting the electronic components on the printed board by the automatic insertion machine is the shortest even if the order of inserting the electronic components is restricted. As much as possible, the insertion order of electronic components can be optimally determined.

[Brief description of drawings]

FIGS. 1 and 2 (a) and (b) are diagrams for explaining the outline of the basic principle of the present invention, and FIGS. 3 (a) and 3 (b) are the improved principle of the present invention. FIG. 4, FIG. 4 and FIG. 5 for explaining the outline are diagrams for explaining the effect of the improved principle, and FIG. 6, FIG. 7 (a), (b), and FIG. Figure, Figure 9 (a), (b)
FIG. 6 is a diagram for explaining a case where the improved principle is applied to mounting electronic components on a printed board.

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Claims (1)

[Claims] 1. When the insertion positions of various electronic components on a printed board are known in advance, the electronic components are sequentially gripped by an insertion head by an automatic insertion machine and then sequentially inserted into predetermined insertion positions. In this case, each insertion position is regarded as a point, a distance between two points relating to an arbitrary combination is given in advance, and the order in which an electronic part is inserted in a part Determines the insertion order that satisfies the restrictions on the insertion order of parts and that the sum of the movement distances of the insertion heads when inserting parts is the shortest for a number of points to which the restrictions are given based on the interference check A method for determining the electronic component insertion order, wherein each time a specific point is selected from a set of points that satisfy a constraint condition in the insertion order of components, the point is removed from the set and the point is removed. By choosing A point for which the constraint condition in the insertion order of parts is removed is newly added to the set, and the one closest to the above-mentioned specific point is selected from the new set as the next specific point. Thus, n (n ≠ 1) points are obtained with a certain specific point as a starting point, and the insertion order of all the parts obtained with respect to the n points including the starting point is calculated in the insertion order. A method for determining an electronic component insertion order, characterized in that the selection of a point next to the starting point as a new starting point is sequentially repeated by selecting one having a shortest moving path that satisfies the constraint condition.