JP3846261B2 - Method for detecting height of substrate upper surface in electronic component mounting apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for detecting the height of the upper surface of a substrate in an electronic component mounting apparatus that obtains the mounting height position of the upper surface of the substrate on which the electronic component is mounted.
[0002]
[Prior art]
In the mounting operation for mounting the electronic component on the substrate, the electronic component is landed and mounted on the upper surface of the substrate by lowering the suction nozzle holding the electronic component with respect to the substrate. In order to satisfactorily land the electronic component without causing an impact or displacement on the electronic component, the mounting height position, that is, the lowering of the suction nozzle is required in order to bring the electronic component close to the upper surface of the substrate without excess or deficiency. It is necessary to accurately set the target height position as numerical data.
[0003]
Conventionally, when setting the mounting height position, the thickness dimension of the board on which the electronic component is to be mounted differs depending on the board type. Therefore, by inputting the board thickness data every time the board type changes, the thickness of each board is changed. The difference was corrected.
[0004]
[Problems to be solved by the invention]
However, in the above method, there is a case where the substrate thickness data given as the component data does not exactly match the thickness of the actual substrate due to variations, or an error from the actual thickness dimension such as a mistake at the time of data input may occur. In such a case, the set mounting height position is naturally not correct, and a mounting defect occurs.
[0005]
For example, when the mounting height position to be set is too high, the electronic component held by the suction nozzle falls without landing on the upper surface of the substrate, causing a positional deviation. When the mounting height position is too low, the suction nozzle is lowered even after the electronic component comes into contact with the upper surface of the substrate, and the electronic component is pressed against the substrate with an excessive pressing force. As described above, the conventional electronic component mounting method has a problem that a mounting defect may occur due to the setting of the mounting height position on the upper surface of the substrate.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for detecting a board top surface height in an electronic component mounting apparatus that can accurately detect a board top surface height and automatically set a mounting height position. To do.
[0007]
[Means for Solving the Problems]
The electronic component mounting apparatus according to claim 1, wherein the substrate upper surface height detection method includes: picking up an electronic component by vacuum suction from a component supply unit using a suction nozzle of a transfer head and mounting the electronic component on the substrate; A method for detecting a height of a substrate upper surface in an electronic component mounting apparatus for detecting a height position of the substrate upper surface positioned by a positioning unit, wherein a vacuum suction source is set with the transfer head positioned above the substrate. The vacuum suction circuit that is connected to the suction nozzle and the vacuum suction source is driven while the suction nozzle is lowered with respect to the substrate by driving the lifting / lowering means that raises and lowers the suction nozzle while driving and sucking vacuum from the suction nozzle. a step of measuring the flow rate of air passing through the vacuum suction circuit by the flow rate sensor is sucked from the suction nozzle, the flow rate measurement result preset of the Said output height indicated value of the lifting means at the lower end is the timing determined timing became flow rate of air passing through the vacuum suction in the circuit in contact with the timing on the substrate of the suction nozzle as the substrate upper surface height Including the step of.
[0008]
According to the present invention, the suction nozzle is lowered with respect to the substrate while performing vacuum suction from the suction nozzle, and the flow rate of the air sucked from the suction nozzle by the flow rate sensor and passing through the vacuum suction circuit is measured. Is determined in advance at the timing at which the lower end of the suction nozzle comes into contact with the substrate, and the flow rate of the air passing through the vacuum suction circuit is obtained. By outputting the height, it is possible to accurately detect the height of the upper surface of the substrate and automatically set the mounting height position.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of an electronic component mounting apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a transfer head of the electronic component mounting apparatus according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is an explanatory diagram of flow rate data of a vacuum suction circuit in the electronic component mounting apparatus according to the embodiment of the present invention, FIG. 5 and FIG. FIG. 7 is an explanatory diagram of a board top surface height detection process in the electronic component mounting apparatus of one embodiment of the present invention, and FIG. 7 is an operation explanatory diagram of the electronic component mounting apparatus of one embodiment of the present invention.
[0010]
First, an electronic component mounting apparatus will be described with reference to FIG. In FIG. 1, the electronic component mounting apparatus 1 includes a transport path 2 arranged in the X direction, and the transport path 2 is a board positioning unit that transports and positions the board 3. On the front side of the conveyance path 2, an electronic component supply unit 4 is arranged, and the component supply unit 4 is provided with a large number of tape feeders 5 for supplying taped electronic components.
[0011]
A transfer head 6 is mounted above the transport path 2 and the component supply unit 4 so as to be horizontally movable by horizontal movement means (not shown). The transfer head 6 is a multi-type head provided with a plurality of suction nozzles 18 (see FIGS. 2 and 3), picks up electronic components from the pickup position of the tape feeder 5 by the suction nozzles 18, and the substrate on the transport path 2. Transfer to No.3.
[0012]
A line camera 7 is disposed on the movement path of the transfer head 6 between the conveyance path 2 and the component supply unit 4. While moving the transfer head 6 holding the electronic component horizontally above the line camera 7, the light incident through the optical system of the line camera 7 is received by a one-dimensional line sensor, thereby imaging the electronic component. And recognize.
[0013]
Next, the transfer head 6 will be described with reference to FIG. In FIG. 2, the transfer head 6 is mounted on the Z-axis table 10. The Z-axis table 10 includes a feed screw 12 that is rotationally driven by a motor 11 and a nut member 12a into which the feed screw is screwed. The Z-axis drive unit 19 rotationally drives the motor 11 to transfer the transfer head 6. Goes up and down.
[0014]
The motor 11 includes an encoder 11a. When the height detection unit 20 receives a pulse signal from the encoder 11a, the position of the transfer head 6 in the Z-axis direction, that is, the height position is detected. The height position detection result is sent to the control unit 25. Then, the control unit 25 controls the Z-axis drive unit 19 based on the height position detection result, whereby the transfer head 6 can be raised or lowered with an arbitrary height position as a target.
[0015]
The transfer head 6 includes an elevating block 14 coupled to a box-shaped member 13, and six air cylinders 15 are disposed on the upper surface of the box-shaped member 13 at equally spaced positions on the circumference. . The air cylinder 15 is a double rod type, and rods 15a protrude in both the upper and lower directions. The downwardly projecting rod 15 a is rotatably coupled to the nozzle lifting rod 16, and the nozzle lifting rod 16 is coupled to a mounting portion 17 that projects downward from the lower end of the lifting block 14. A suction nozzle 18 is detachably mounted on the mounting portion 17. The suction nozzle 18 is provided with a suction hole 18a. By vacuum suction from the suction hole 18a, the electronic component is sucked and held on the suction surface at the lower end.
[0016]
In the above configuration, by driving the air cylinder 15, the suction nozzle 18 moves up and down individually by a predetermined stroke with respect to the transfer head 6. That is, the Z-axis table 10 is a lifting means for lifting the suction nozzle 18 and the air cylinder 15 is an individual vertical movement means. Based on the height information from the encoder 11 a of the Z-axis table 10, the height detection unit 20, as shown in FIG. 2, the height position Zn (Z of the lower end portion of the suction nozzle 18 lowered by the air cylinder 15. The Z coordinate value in the coordinate system of the axis drive unit 19) is output as the height instruction value.
[0017]
Here, the configuration of a vacuum suction / control system that performs vacuum suction from the suction nozzle 18 will be described with reference to FIG. As shown in FIG. 3, a vacuum valve 21 is connected to the mounting portion 17 to which the suction nozzle 18 is mounted, and the vacuum valve 21 is connected to a vacuum pump 23 that is a vacuum suction source. The vacuum pump 23 is driven in a state where the suction nozzle 18 is mounted on the mounting portion 17 and the vacuum valve 21 is opened, whereby vacuum suction is performed from the suction hole 18a provided in the suction surface at the lower end of the suction nozzle 18. To do.
[0018]
The circuit from the suction nozzle 18 to the vacuum pump 23 is a vacuum suction circuit through which air passes during vacuum suction. A filter 28 is built in the mounting portion 17, and the air sucked from the suction nozzle 18 passes through the filter 28, whereby the foreign matter sucked together with the air during vacuum suction is collected by the filter 28.
[0019]
A flow rate sensor 22 is interposed in the vacuum suction circuit between the vacuum valve 21 and the vacuum pump 23. The flow sensor 22 continuously measures the amount of air flowing in the vacuum suction circuit per unit time by vacuum suction by detecting the temperature difference between the fluids flowing inside. The measurement result of the flow sensor 22 is sent to the determination unit 24.
[0020]
The determination unit 24 compares the flow rate measurement result of the flow rate sensor 22 with the flow rate data stored in the storage unit 26, thereby determining whether there is an electronic component at the lower end of the suction nozzle 18 and the suction state of the vacuum suction system. Determine the state. Moreover, the determination part 24 monitors the flow measurement result continuously measured, and detects the timing when the flow measurement value reaches a predetermined value. The determination result and the detected timing are sent to the control unit 25.
[0021]
The control unit 25 controls the notification unit 27 on the basis of the determination result to notify the pickup error, take-out component detection, and the like, and the height indication value of the Z-axis table 10 at the detected timing is used as the nozzle height data. Is stored in the storage unit 26.
[0022]
Next, flow rate data of a vacuum suction circuit that performs vacuum suction from the suction nozzle 18 by the vacuum pump 23 will be described with reference to FIG. 4 shows the flow rate measured by the flow sensor 22, the state of the vacuum suction system, that is, various states that can occur in the vacuum suction system during maintenance and inspection of the electronic component mounting apparatus, and the flow rate of the vacuum suction circuit. It shows the corresponding relationship. F0 to f5 set on the flow axis are flow data set as threshold values for determining each state, and are set based on actual measurement data obtained by the flow sensor 22 after actually reproducing each state. Is done.
[0023]
Here, the states of the vacuum suction system are [No suction nozzle], [Filter clogging], [Suction nozzle installation abnormal], [No parts], [Part suction status abnormal], [Part normal suction] and [Suction contact area]. 7 states are assumed. Hereinafter, the correspondence between each state and the flow rate data will be described.
[0024]
“No suction nozzle” indicates a state in which the suction nozzle 18 is not mounted on the mounting portion 17, and in this state, the internal hole in the mounting portion 17 remains open. The flowing flow is the largest. Here, if the flow rate measurement result is equal to or greater than the nozzleless flow rate f0, it is determined that there is no suction nozzle. From this [no suction nozzle], the opening degree of the vacuum suction circuit decreases in the order of each state described below, the degree of the closed state increases, and the value of each threshold value also decreases.
[0025]
[Filter clogging] indicates that the amount of foreign matter collected by the filter 28 in the mounting portion 17 has increased, and the pressure loss during vacuum suction has increased to such an extent that the filter 28 needs to be replaced or cleaned. Yes. Here, if the flow rate measurement result when the suction nozzle 18 is not mounted on the mounting portion 17 is equal to or less than the filter clogging flow rate f1, it is determined that the filter is clogged.
[0026]
“Suction nozzle mounting abnormality” indicates a state in which the suction nozzle 18 of the mounting portion 17 is mounted, but a leak is caused by a defect such as a foreign object biting around the mounting hole. If the flow rate measurement result in a state where the suction nozzle 18 is mounted on the mounting portion 17 is equal to or higher than the nozzle abnormal flow rate f2, it is determined that the suction nozzle is abnormal.
[0027]
[No parts] indicates a state in which no electronic parts are present on the suction surface of the suction nozzle 18 even though the vacuum suction circuit is in the suction state. Similarly, if the flow rate measurement result with the suction nozzle 18 mounted on the mounting portion 17 is equal to or greater than the component-free flow rate f3, it is determined that there is no component.
[0028]
“Part suction state abnormality” indicates a state in which an electronic component is present on the suction surface of the suction nozzle 18 but the suction position and posture are not normal and excessive leakage from the suction hole 18a occurs. If the suction nozzle 18 is attached and the flow rate measurement result in the component suction state is equal to or higher than the suction abnormal flow rate f4, it is determined that the component suction state is abnormal.
[0029]
“Part normal suction” indicates a state in which the electronic component is normally sucked and held by the suction nozzle 18. Similarly, if the flow rate measurement result in the part suction state does not satisfy the suction abnormal flow rate f 4, Determined. [Suction surface contact] lowers the transfer head 6, presses the suction surface of the suction nozzle 18 against a flat solid surface such as a substrate upper surface or a measurement reference surface, and presses the suction surface. 18a shows a closed state. If the flow rate measurement result is equal to or less than the suction surface contact flow rate f5, it is determined that the suction surface contact is made. This determination is used for detecting the suction height of the suction nozzle 18 and detecting the height of the upper surface of the substrate. The flow rate of zero corresponds to the state where the vacuum suction circuit is completely closed.
[0030]
The electronic component mounting apparatus is configured as described above, and the substrate top surface height detection operation in the electronic component mounting operation will be described below with reference to FIGS. Prior to the start of the mounting operation, first, the substrate 3 to be mounted is positioned on the transport path 2 and the lower surface is received. Then, the transfer head 6 is moved onto the substrate 3 (substrate thickness dimension T1), and among the six suction nozzles 18, the reference suction nozzle 18 is lowered by the air cylinder 15, and the Z-axis table 10 is used. The suction nozzle 18 is gradually lowered with respect to the substrate 3 as shown in FIG.
[0031]
When the suction nozzle 18 is lowered, the vacuum valve 21 is opened and vacuum suction is performed from the suction hole 18a at the lower end of the suction nozzle 18. The flow rate passing through the vacuum suction circuit at this time is measured by the flow rate sensor 22 and sent to the determination unit 24. FIG. 6A shows the change over time in the flow rate obtained by this flow rate measurement. At the beginning of the lowering of the suction nozzle 18, since the suction hole 18a is in a completely open state, the flow rate exceeds the component-free flow rate f3.
[0032]
FIG. 6B shows the change with time of the height instruction value Z (the height position of the lower end portion of the suction nozzle 18) during the lowering operation of the suction nozzle 18. The height instruction value Z decreases as the suction nozzle 18 descends. As the suction nozzle 18 descends, the lower end of the suction nozzle 18 approaches the upper surface of the substrate 3 and the vacuum suction from the suction hole 18a is hindered. As shown in FIG. It decreases and decreases to the suction surface contact flow rate f5.
[0033]
The timing t1 when the flow rate is reduced to the suction surface contact flow rate f5, that is, the timing t1 when the lower end portion of the suction nozzle 18 contacts the upper surface of the substrate 3 as shown in FIG. The timing t1 is sent to the control unit 25 that monitors the height instruction value Z. Accordingly, the control unit 25 outputs the height instruction value Z at the timing t1 as the substrate upper surface height Zn (B) and stores it in the storage unit 26.
[0034]
FIG. 7 shows an operation when the electronic component P is mounted on the board 3 based on the board upper surface height Zn (B) thus detected. In the mounting operation, the transfer head 6 first moves to the component supply unit 4, where the suction nozzle 18 picks up the electronic component P. Thereafter, when the transfer head 6 moves, the suction head 18 holding the electronic component P is positioned on the substrate 3 as shown in FIG. At this time, the thickness dimension T2 of the electronic component P is given in advance on the mounting data.
[0035]
FIG. 7B shows the operation of lowering the suction nozzle 18 and mounting the electronic component P on the substrate 3. At this time, the height position (Zn (B) -T2) obtained by subtracting the thickness dimension T2 of the electronic component P from the substrate upper surface height Zn (B) detected in advance is the lowering target height position by the Z-axis table 10, That is, it is automatically set as the mounting height position. Thereby, in the mounting operation, the suction surface at the lower end of the suction nozzle 18 is surely stopped at a height position above the upper surface of the substrate 3 by the thickness dimension T2.
[0036]
Therefore, the electronic component P is ensured to have good mounting quality without causing a malfunction due to an inappropriate lowering stop height of the suction nozzle 18, that is, excessive pressing of the electronic component P or positional displacement at the time of mounting. Is done. Further, when setting the mounting height position, it is not necessary to consider the thickness dimension T1 of the substrate 3 at all. Therefore, the data input of the substrate thickness dimension, which has been conventionally required, and the receiving member according to the thickness dimension of the substrate. Therefore, the work efficiency associated with the change of the substrate type, such as the setup change work to be replaced, can be reduced and the work efficiency can be improved.
[0037]
【The invention's effect】
According to the present invention, the suction nozzle is lowered with respect to the substrate while performing vacuum suction from the suction nozzle, and the flow rate of the air sucked from the suction nozzle by the flow rate sensor and passing through the vacuum suction circuit is measured. Is determined in advance at the timing when the lower end of the suction nozzle comes into contact with the substrate and the flow rate of the air passing through the vacuum suction circuit is obtained, and the height indication value of the lifting means at this timing is set as the height of the upper surface of the substrate. As a result, it is possible to accurately detect the height of the upper surface of the substrate and automatically set the mounting height position.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electronic component mounting apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view of a transfer head of the electronic component mounting apparatus according to an embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the suction / control system of the electronic component mounting apparatus according to the embodiment. FIG. 4 is an explanatory diagram of flow rate data of the vacuum suction circuit in the electronic component mounting apparatus according to the embodiment of the present invention. FIG. 6 is an explanatory diagram of a substrate top surface height detection process in the electronic component mounting apparatus according to the embodiment of the invention. FIG. 6 is an explanatory diagram of a substrate top surface height detection process in the electronic component mounting apparatus according to the embodiment of the invention. Operation explanatory diagram of electronic component mounting apparatus according to one embodiment of the present invention
DESCRIPTION OF SYMBOLS 1 Electronic component mounting apparatus 3 Board | substrate 4 Component supply part 6 Transfer head 10 Z-axis table 18 Suction nozzle 20 Height detection part 22 Flow rate sensor 23 Vacuum pump 24 Determination part 25 Control part 26 Memory | storage part

Claims (1)

In an electronic component mounting apparatus that picks up an electronic component from a component supply unit by a suction nozzle of a transfer head by vacuum suction and mounts the electronic component on a substrate, the electronic component mounting that detects the height position of the upper surface of the substrate positioned in the substrate positioning unit A method of detecting the height of the upper surface of the substrate in the apparatus, comprising: lifting means for raising and lowering the suction nozzle while driving the vacuum suction source with the transfer head positioned above the substrate and performing vacuum suction from the suction nozzle. Air that is driven to lower the suction nozzle relative to the substrate, and is sucked from the suction nozzle by a flow rate sensor interposed in the vacuum suction circuit that connects the suction nozzle and the vacuum suction source, and passes through the vacuum suction circuit. wherein the a step of measuring the flow rate, at the time when the lower end of the suction nozzle flow rate measurement result is preset in contact with the substrate Board in the electronic component mounting apparatus characterized by the idle suction to pass through the circuit obtains the timing became flow of air the lifting means in the timing height indication value and a step of outputting as the substrate upper surface height How to detect the height of the top surface.

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