Component mounting system and control method for the component mounting system

Abstract

This technology provides a way to add reference points to correct the placement of components without redesigning the circuit board. [Solution] The component mounting apparatus comprises a calculation unit that calculates a virtual reference point from at least two marks on a circuit board, a correction unit that corrects the position on the circuit board where the component should be mounted based on the reference point, and a mounting unit that mounts the component at the position corrected based on the reference point.

Description

Technical Field

[0001] This specification relates to a component mounting system for mounting components on a substrate and a control method thereof.

Background Art

[0002] Patent Document 1 discloses a component mounting system that corrects the mounting position of pins by using a polarity mark.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a desire to correct the position where a component is to be mounted based on a point other than an existing mark. To meet this desire, it is assumed that a new mark is added to the substrate. However, adding a new mark results in a design change of the substrate. This specification provides a technique for adding a reference point for correcting the position where a component is to be mounted without changing the design of the substrate.

Means for Solving the Problems

[0005] The component mounting device disclosed in this specification includes a calculation unit that calculates a virtual reference point from at least two marks on a substrate, a correction unit that corrects the position where a component is to be mounted on the substrate based on the reference point, and a mounting unit that mounts the component at the position corrected based on the reference point.

[0006] According to the above configuration, a virtual reference point is calculated from at least two actual marks. Since it is a virtual reference point, there is no need to add new marks to the circuit board. This addresses the need to correct the position of components based on points other than those already present. [Brief explanation of the drawing]

[0007] [Figure 1] This is a conceptual diagram of a component mounting device. [Figure 2] This is a block diagram of a component mounting device. [Figure 3] This diagram shows the correction method according to the first embodiment. [Figure 4] This figure shows the correction method according to the second embodiment. [Modes for carrying out the invention]

[0008] (First embodiment) (Configuration of component mounting device 2; Figures 1 and 2) The component mounting device 2 is a device for mounting components 4 onto a circuit board 6. Component 4 is an electronic component such as a resistor. The component mounting device 2 includes a robot 20, a nozzle 22, a camera 24, a component supply unit 26, a conveyor 28, and a control unit 30. XYZ coordinates are defined in the figure.

[0009] The substrate 6 is transported into the component mounting device 2 by a conveyor 28 extending in the Y direction. The components 4 are supplied by a component supply unit 26. The component supply unit 26 is, for example, a component feeder or a component tray.

[0010] The robot 20 is movable in the horizontal direction (i.e., the XY direction). A nozzle 22 for picking up parts is mounted on the underside of the robot 20. The nozzle 22 is movable in the vertical direction (i.e., the Z direction). For example, the robot 20 moves to the upper side of the parts supply unit 26. The nozzle 22 picks up a part 4 from the parts supply unit 26. After the nozzle 22 has picked up the part 4, the robot 20 moves from the upper side of the parts supply unit 26 to the upper side of the substrate 6 that has been transported by the conveyor 28. The nozzle 22 mounts the part 4 that is being held onto the substrate 6. By repeating this process, multiple parts 4 are mounted onto the substrate 6.

[0011] Furthermore, a camera 24 capable of imaging the circuit board 6 is mounted on the underside of the robot 20. Two marks 6a and 6b are present on the circuit board 6. The component mounting device 2 recognizes the two marks 6a and 6b from the image of the circuit board 6 captured by the camera 24 (hereinafter referred to as the "captured image"). The component mounting device 2 then uses the recognized two marks 6a and 6b to correct the position in which the components 4 are mounted on the circuit board 6.

[0012] The two marks 6a and 6b are positioned at both ends of the substrate 6. Furthermore, the shapes of marks 6a and 6b are not limited to circles; they may also be polygons such as triangles or quadrilaterals, predetermined strings of characters, predetermined symbols, etc.

[0013] Each of the parts 20 to 28 is controlled by the control unit 30. The control unit 30 comprises a CPU 32 and a memory 34. The CPU 32 can perform various processes according to the program 40 stored in the memory 34.

[0014] Memory 34 further stores drawing data 50. The drawing data 50 includes coordinate points indicating the position where each of the multiple components 4 is mounted. Here, the coordinate points are points in a planar coordinate system with one of the four corners of the circuit board 6 as the origin. The drawing data 50 also includes coordinate points indicating the positions of marks 6a and 6b.

[0015] Drawing data 50 is stored in the memory 34 by the user of the component mounting apparatus 2 before the job of mounting the component 4 on the substrate 6 is carried out. The component mounting apparatus 2 mounts the component 4 at the position indicated by the drawing data 50.

[0016] The substrate 6 expands and contracts due to heat or the like. When the substrate 6 expands and contracts, the position where the component 4 is mounted may deviate from the position indicated by the drawing data 50. Therefore, it is necessary to correct the position where the component 4 is mounted from the position indicated by the drawing data 50.

[0017] For example, there is a method of calculating the difference between the coordinate point of the mark 6a indicated by the drawing data 50 and the actual position of the mark 6a recognized from the captured image, and correcting the coordinate point of the component indicated by the drawing data 50 from the difference. This conventional method is a well-known method, and a detailed description thereof will be omitted.

[0018] On the other hand, there is a desire to correct the position where the component 4 is mounted based on points other than the existing marks 6a and 6b. In order to meet this desire, it is assumed that a new mark is added to the substrate 6. However, adding a new mark results in a design change of the substrate 6. In the present embodiment, a method of adding a reference point for correcting the position where the component is mounted without changing the design of the substrate 6 is disclosed.

[0019] (Method for correcting the position where the component 4 is mounted; FIG. 3) Referring to FIG. 3, the correction method according to the present embodiment will be described. In this correction method, a virtual reference point 100 is calculated from two marks 6a and 6b, and the position where the component 4 is mounted is corrected based on the reference point 100.

[0020] The drawing data 50 includes the coordinate point Ma = (xa, ya) of the mark 6a, the coordinate point Mb = (xb, yb) of the mark 6b, and the coordinate point R1 = (xr1, yr1) of the component 4. The CPU 32 calculates the center point of the line segment connecting the coordinate point Ma and the coordinate point Mb as the coordinate point Md = (xd, yd) of the reference point 100.

[0021]

Number

[0022] The CPU 32 recognizes two marks 6a and 6b from the imaging coordinates, and calculates the actual coordinate points Ma’=(xa’, ya’) of the mark 6a and the actual coordinate points Mb’=(xb’, yb’) of the mark 6b. The CPU 32 calculates the actual coordinate point Md’=(xd’, yd’) of the reference point 100 based on the center point of the line segment connecting the actual coordinate points Ma’ and Mb’.

[0023]

Number

[0024] Also, the CPU 32 calculates the theoretical inclination Q (i.e., the theoretical value) of the substrate 6 from the coordinate points Ma and Mb of the marks 6a and 6b in the drawing data 50, and calculates the actual inclination Q’ (i.e., the measured value) of the substrate 6 from the actual coordinate points Ma’ and Mb’ of the marks 6a and 6b. Then, the CPU 32 calculates the difference q = Q’ - Q between the theoretical value and the measured value.

[0025]

Number

[0026]

Number

[0027] Also, the CPU 32 calculates the theoretical distance L between the marks 6a and 6b from the coordinate points Ma and Mb of the marks 6a and 6b in the drawing data 50, and calculates the actual distance L’ between the marks 6a and 6b from the actual coordinate points Ma’ and Mb’ of the marks 6a and 6b. Then, the CPU 32 calculates the elongation rate α = L’ / L of the substrate 6.

[0028]

Number

[0029]

number

[0030] Then, the CPU32 calculates the coordinate point R1'=(xr1', yr1') of part 4 by correcting the coordinate point R1=(xr1, yr1) with respect to the reference point 100, based on the following formula. The CPU32 then mounts part 4 to the corrected coordinate point R1' with respect to the reference point 100.

[0031]

number

[0032] (Effects of this embodiment) In this embodiment, a virtual reference point 100 is calculated from two actual marks 6a and 6b. Since a virtual reference point 100 is used, there is no need to add new marks to the circuit board 6. In particular, this embodiment does not require any changes to the hardware design of the circuit board 6, and can be achieved through software modifications. A new reference point 100 for correction can be easily added.

[0033] Furthermore, marks 6a and 6b are placed at the edges of the substrate 6. This is because there is a high probability that components 4 will be mounted near the center of the substrate 6, and there are design constraints on the substrate 6. According to the configuration of this embodiment, a reference point 100 can be defined near the center of the substrate 6, where it is difficult to place marks, that is, at the midpoint between marks 6a and 6b. In addition, by setting the reference point 100 near the center of the substrate 6 where components 4 are mounted, the mounting position of components 4 mounted near the center of the substrate 6 can be corrected with high accuracy.

[0034] Furthermore, in this embodiment, the CPU 32 switches between a conventional method and the method shown in Figure 3 for correcting the mounting position of component 4 in response to user instructions. The method for correcting the position of the component can be switched according to the user's request. In the modified example, the above switching does not need to be performed.

[0035] (Correspondence) The component mounting device 2, the circuit board 6, and the component 4 are examples of a "component mounting system," a "circuit board," and a "component," respectively. Marks 6a and 6b are examples of "at least two marks." Marks 6a and 6b are examples of a "first mark" and a "second mark," respectively. Reference point 100 is an example of a "reference point." The coordinate points indicated by the drawing data 50 are an example of a "position." The control unit 30 is an example of a "calculation unit" and a "correction unit." The control unit 30 and the robot 20 are an example of a "mounting unit."

[0036] (Second example) (Method for correcting the mounting position of component 4; Figure 4) In this embodiment, in addition to the two marks 6a and 6b, a mark 6c is present on the substrate 6. In this embodiment, the mounting position of the component 4 is corrected based on a reference point 100 calculated from the three marks 6a, 6b, and 6c.

[0037] Referring to Figure 4, the correction method according to this embodiment will be described. The drawing data 50 includes the coordinate point Ma of mark 6a, the coordinate point Mb of mark 6b, the coordinate point Mc=(xc, yc) of mark 6c, and the coordinate point R2=(xr2, yr2) of part 4. The CPU 32 calculates the intersection point of the perpendicular line extended from the coordinate point Mc of mark 6c to the line segment connecting the coordinate point Ma of mark 6a and the coordinate point Mb of mark 6b, and the line segment connecting the coordinate point Ma and the coordinate point Mb, as the coordinate point Me=(xe, ye) of the reference point 100.

[0038]

number

[0039]

number

[0040] Furthermore, the CPU 32 recognizes three marks 6a, 6b, and 6c from the image coordinates and calculates the actual coordinate points Ma', Mb', and Mc'=(xc', yc') of marks 6a, 6b, and 6c. The CPU 32 calculates the intersection point of the perpendicular line extended from coordinate point Mc' to the line segment connecting coordinate points Ma' and Mb', and the line segment connecting coordinate point Ma' and Mb', as the actual coordinate point Me'=(xe', ye') of reference point 100.

[0041]

number

[0042]

number

[0043] Then, CPU32 calculates the coordinate point R2'=(xr2', yr2') of part 4 by correcting the coordinate point R2=(xr2, yr2) based on the above intersection reference point 100, using the following formula as the basis.

[0044]

number

[0045] According to the configuration of this embodiment, the reference point 100 can be calculated using the three marks 6a, 6b, and 6c.

[0046] (Correspondence) Marks 6a, 6b, and 6c are examples of "at least two marks." Marks 6a, 6b, and 6c are examples of "the first mark," "the second mark," and "the third mark," respectively.

[0047] Points to note regarding the component mounting system and its control method described in the embodiment are described below. The correction method shown in Figures 3 and 4 may be performed not only by the CPU 32 of the component mounting device 2, but also by an external device (e.g., a PC or server) that can communicate with the component mounting device 2. In this modified example, the external device is an example of a "calculation unit" and a "correction unit".

[0048] In the first embodiment, the reference point 100 is not limited to the center point on the line segment connecting mark 6a and mark 6b. For example, the reference point 100 on the line segment connecting mark 6a and mark 6b may be shifted to one of mark 6a or mark 6b by a predetermined ratio.

[0049] In the second embodiment, the reference point 100 is not limited to the intersection point with a perpendicular line extended from the coordinate point Mc of mark 6c, but may also be defined as the intersection point with a diagonal line having a predetermined angle from the coordinate point Mc of mark 6c.

[0050] Furthermore, the method for defining the reference point 100 is not limited to the methods shown in Figures 3 and 4; for example, it could be the intersection of a circle centered at coordinate point Ma and a circle centered at coordinate point Mb. Generally speaking, the reference point only needs to be calculated from at least two marks.

[0051] Furthermore, the technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated herein or in the drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0052] 2: Component mounting equipment 4: Parts 6: Circuit board 6a, 6b, 6c: Mark 20: Robot 22: Nozzle 24: Camera 26: Parts Supply Department 28: Conveyor 30: Control Unit 32:CPU 34: Memory 40: Program 50: Drawing data 100:Reference point

Claims

1. A component mounting system, A calculation unit that calculates a virtual reference point from at least two marks on the circuit board, A correction unit that corrects the position on the substrate where components should be mounted, based on the aforementioned reference point, A mounting unit for mounting the component at the position corrected based on the aforementioned reference point, A component mounting system equipped with the following features.

2. The aforementioned at least two marks include a first mark and a second mark, The component mounting system according to claim 1, wherein the reference point is defined on the line segment connecting the first mark and the second mark.

3. The component mounting system according to claim 2, wherein the reference point is defined as the center point of the line segment connecting the first mark and the second mark.

4. The aforementioned two marks further include a third mark, The component mounting system according to claim 2, wherein the reference point is defined as the intersection of a second line segment extended from the third mark to the line segment connecting the first mark and the second mark, and the line segment connecting the first mark and the second mark.

5. The component mounting system according to claim 4, wherein the second line segment is a perpendicular line extended from the third mark to the line segment connecting the first mark and the second mark.

6. The aforementioned component mounting system further, A component mounting system according to any one of claims 1 to 5, comprising a switching unit for switching between a first method of correcting the position based on the reference point and a second method of correcting the position based on one of the at least two marks.

7. A method for controlling a component mounting system, A calculation process for calculating a virtual reference point from at least two marks on the circuit board, A correction step in which the position where components should be mounted on the substrate is corrected based on the aforementioned reference point, A mounting step of mounting the component at the position corrected based on the aforementioned reference point, A control method comprising:

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