JPH0621299U - Component drop detector - Google Patents

Abstract

(57) [Summary] [Purpose] To detect the drop of parts quickly and not to miss the drop of parts to improve the drop detection accuracy. A drop detecting means is provided at least below a position where the substrate is completely inverted, and the drop detecting means detects the drop of the dropped component by vibration when the component is dropped.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a component drop detection device that detects a component drop from a board whose front and back are reversed.

[0002]

[Prior art]

 In recent printed circuit boards, in order to mount electronic parts at high density, parts have been mounted on both the front and back surfaces of the board. As described above, in order to mount the components on both surfaces of the printed circuit board, first, the substrate is faced up, and ordinary lead components are inserted into this surface, and the leads are clinched to temporarily fix the components. Next, the substrate is turned upside down with the back side facing up. Then, with the backside up, chip components such as melf resistors are placed directly on the conductor land parts of the board, and soldering is performed on this backside.

In order to mount the components on the back surface of the board in this way, the board must be inverted (180 °) as in the step shown in, but at this time, it should have been temporarily fixed on the front surface of the board. Often, the lead components were not fully pre-fixed (eg, without clinching), and were often dropped from the board. In order to prevent a defective printed circuit board with such a missing component from entering the market, it is necessary to detect this immediately when a component is removed from the printed circuit board and find the defective printed circuit board.

As a device for detecting such a component drop-off, for example, a component drop detection device as disclosed in Japanese Utility Model Publication No. 2-41920 is known. This component drop detection device will be described below with reference to FIG. The printed circuit board 1 having the lead component 2 mounted on the surface A is transported by the transport conveyor 3. After that, when the printed circuit board 1 enters the hole 4a in the reversing device 4, the reversing device 4 detects this and reverses 180 ° while sandwiching the printed circuit board 1 by the hole 4a. Then, when the printed circuit board 1 inverted by 180 ° is placed on the transfer conveyor 5, the printed circuit board 1 is naturally separated from the hole 4a by the transfer force of the transfer conveyor 5, and the printed circuit board 1 is transferred by the transfer conveyor 5, as shown by. Chip components and the like are mounted on the back surface B of the printed circuit board 1 as in the process. The lead component 2 dropped when the print substrate 1 is inverted is guided to a guide 7 provided below the reversing device 4. The guide 7 is provided with an optical sensor 9, and the optical sensor 9 is composed of a light emitting portion 91 that outputs detection light, such as a light emitting diode, and a light receiving portion 92 that receives the detection light.

When the dropped lead component 2 passes the detection light, the detection light is blocked, and thus the light receiving unit 92 detects the fall of the lead component 2 by the blocking of the detection light, and turns on the display lamp 6. And give an alarm. Therefore, it is possible to detect the fall of the lead component 2 when the substrate is turned over, and it is possible to prevent the defective substrate from which the component is dropped from entering the market.

[0006]

[Problems to be solved by the device]

 However, if the optical sensor 9 is used to detect such a component drop, the following problems will occur. FIG. 4 is a top view of the guide 7 as viewed in the vertical direction (the direction indicated by the arrow D in FIG. 3). As shown in FIG. 4, the detection light is linear, so the detection range is very narrow. Therefore, in order to allow the dropped lead component 2 to pass through this detection range, the diameter of the guide 7 must be reduced. However, if the diameter of the guide 7 is reduced and the guide 7 is narrowed in this way, the lead component 2 may be caught in the guide 7 and may stop inside the guide 7. Then, as shown in FIG. 3, when the stop position of the lead component 2 is above the detection range, the lead component 2 naturally does not pass through the detection range, and therefore the lead component 2 falls off the print substrate 1. However, this will not be detected. On the contrary, if the diameter of the guide 7 is increased in order to prevent the lead component 2 from being caught, the ratio of the detection range to the aperture becomes smaller, and the component 2 falls without passing through the detection range. As a result, the fall of the lead component 2 cannot be detected. Further, if an attempt is made to increase the detection range, the light emitting unit 91 and the light receiving unit 92 are required correspondingly, which causes a cost problem.

An object of the present invention is to detect a component drop quickly when the substrate is turned over and to detect the component drop accurately without overlooking it.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a transfer means for transferring a board on which a component is mounted, a reversing means for reversing the board transferred by the transfer means, and at least the above-mentioned reversing means. Drop detection means provided below the reversal completion position of the substrate and detecting the fall of the component mounted on the substrate by the vibration at the time of the fall.

[0009]

[Action]

 In the present invention, instead of using an optical sensor, a drop detecting means for detecting a drop of a component by vibration at the time of the drop is used. Most of the parts fall off when the reversing means completes the reversing of the substrate. In the present invention, the drop detecting means is provided at least below the reversing completion position. Then, when the component falls off the board during reversal, the component falls toward the drop detection means, and when the component collides with the drop detection means, the drop detection means vibrates at this time. Detect the fall. In this way, in the proposed method, the drop of the component is detected by the vibration, so that the detection range can be widened and the drop of the component can be accurately detected without overlooking. Therefore, in this proposal, there is no problem such as missing of parts that occurs due to a narrow detection range such as an optical sensor.

[0010]

【Example】

 FIG. 1 shows a component drop detection device according to an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals, and the configurations and operations of the transport conveyors 3 and 5 and the reversing device 4 have already been described, and thus the description thereof will be omitted. As described with reference to FIG. 3, the board 1 on which the lead component 2 is mounted is reversed by the reversing device 4, but in this example, it is a fall detection means for detecting the fall of the lead component 2 during or after reversal. A drop detector 10 is provided from below the position where the printed circuit board 1 is completely inverted to below the conveyor 5.

The drop detector 10 includes a component receiving portion 11 that directly receives a fall of the lead component 2, a vibration sensor 12 that detects a vibration state of the receiving portion 11, and a support 13 that supports the vibration sensor 12. It comprises a spring 14 provided below the abutment 13 and a base 15 that supports the spring 14 and is in direct contact with the floor surface 16. The component receiving portion 11 is a rectangular shape made of a thin iron plate. FIG. 2 shows a top view at this time as seen from the arrow C in FIG. The vibration sensor 12 is composed of a movable portion 121 and a main body 122. The movable portion 121 is composed of a magnetic body that is vertically movable in the main body 122, and directly contacts the component receiving portion 11 to support the component receiving portion 11 by magnetic force. A piezoelectric element (not shown) and a detection circuit are provided in the main body 122. The detection circuit in the main body 122 converts the pressing force (strain amount) when the movable portion 121 directly contacts the piezoelectric element into a voltage, It is to judge whether this voltage (pressing force) is a predetermined value or more. Therefore, in this example, normally, the movable part 121 hardly vibrates due to the action of the spring 14 which will be described later, but when the lead component 2 falls and collides with the component receiving part 11, it moves together with the component receiving part 11 due to the collision of the lead component 2. The part 121 vibrates greatly in the vertical direction. Due to this vibration, a large pressing force is generated in the piezoelectric element, and when the voltage (pressing force) when the movable portion 121 vibrates in the main body 122 of the vibration sensor 12 becomes a predetermined value or more, the lead component 2 falls into the component receiving portion 11. It judges that it has fallen and outputs an alarm signal. In this example, the detection sensitivity is increased so that an alarm signal is output even if the lightest lead component 2 is dropped.

The spring 14 at the lower part of the abutment 13 absorbs the vibration transmitted from the peripheral equipment (for example, the transport conveyors 3, 5 etc.) transmitted from the floor surface 16 and prevents the movable portion 121 from vibrating due to this vibration. It is provided for. By doing so, it is possible to prevent erroneous detection of component drop due to vibration from peripheral devices. The drive stop device 17 electrically connected to the vibration sensor 12 stops the drive of the conveyors 3 and 5 when detecting the alarm signal from the vibration sensor 12. Further, the buzzer 18 sounds an alarm when it detects an alarm signal.

Next, the operation of this example will be described. When the lead component 2 comes off from the printed circuit board 1 at the time when the printed circuit board 1 reaches the inversion completion position or when the inverted printed circuit board 1 starts to be conveyed by the conveyor 5, the lead component 2 moves to the component receiving portion 11. To fall. When the lead component 2 collides with the component receiving portion 11, the movable portion 121 vibrates. The main body 122 of the vibration sensor 12 determines that the lead component 2 has dropped when the voltage (pressing force) at the time of vibration of the movable portion 121 exceeds a predetermined value, outputs an alarm signal and activates the buzzer 18, The operator is notified that the parts have fallen, and the drive stop device 17 is operated to stop the drive of the conveyors 3 and 5 so that the defective substrate does not flow to the next process. After that, if the worker picks up the dropped lead component 2 in the component receiving portion 11 and further removes the printed circuit board 1 at the inversion completion position, the original work can be started.

As described above, in this example, the defective substrate can be quickly found when the lead component 2 is detached, and therefore, the defective substrate can be prevented from entering the market. Further, in the present example, the component receiving portion 11 is, so to speak, a detection range, so this detection range is extremely wide, and it is possible to detect this accurately without missing a component drop. Therefore, in this example, there is no problem such as missing of parts that occurs due to a narrow detection range such as an optical sensor.

In this example, the component receiving portion 11, that is, the drop detector 10 is provided from below the reversal completion position to below the transport conveyor, but the present invention is not limited to this. At least below the reversal completion position. Even if the component receiving portion 10 is provided within the range, it is possible to sufficiently detect the component drop.

[0016]

[Effect of device]

 As described above, according to the present invention, it is possible to detect a component drop quickly when the substrate is turned over, and to detect this component drop accurately without overlooking.

[Brief description of drawings]

FIG. 1 is a block diagram showing a component drop detection device according to an embodiment of the present invention.

FIG. 2 is a top view of the component drop detection device as seen from the arrow C in FIG.

FIG. 3 is a configuration diagram showing a conventional component drop detection device.

4 is a top view of the guide 7 as seen from the arrow D in FIG.

[Explanation of symbols]

 10 ... Fall detector 11 ... Component receiving part 12 ... Vibration sensor 13 ... Abutment 14 ... Spring 15 ... Base 16 ... Floor

Claims (1)

[Scope of utility model registration request] 1. Conveying means for conveying a substrate having a component mounted on the surface thereof, reversing means for reversing the substrate conveyed by the conveying means, and at least below a reversal completion position of the substrate by the reversing means. A component drop detection device, which is provided with drop detection means for detecting a drop of a component mounted on the substrate by means of vibration during the fall.