Component-mounting device and method for diagnosing pneumatic circuit

Abstract

This method for diagnosing a pneumatic circuit in a component-mounting device includes: a component-holding head having a suction nozzle; an air flow path leading to the suction nozzle and a flow-path-switching unit for switching the air flow path so as to be connected to one of an atmospheric opening, a positive pressure source, or a negative pressure source; and a pneumatic circuit including a flow-rate-measuring instrument for measuring the air flow rate in the air flow path between the suction nozzle and the flow-path-switching unit. The method for diagnosing the pneumatic circuit determines a failure of the pneumatic circuit on the basis of a measurement result by the flow-rate-measuring instrument of a transient response of the air flow rate associated with switching of the connection by the flow-path-switching unit.

Description

Component mounting device and pneumatic circuit diagnosis method

[0001] The present disclosure relates to a component mounting device that uses a vacuum nozzle to pick up a component by using negative pressure supplied from an air pressure circuit and mounts it on a board, and to a method for diagnosing the air pressure circuit.

[0002] A component mounting device that uses a suction nozzle to suck and hold components and mount them on a circuit board is known to automatically detect clogged suction nozzles and air leaks. Patent Document 1 discloses a suction transfer device (component mounting device) that includes a flow sensor (flow meter) that measures the air flow rate in a mounting / detaching flow path (pneumatic circuit) that supplies positive or negative pressure to the suction nozzle, and that determines that the suction nozzle is clogged if the air flow rate measured by the flow sensor is lower than a reference flow rate.

[0003] International Publication No. 2009 / 005058

[0004] However, in conventional technologies including Patent Document 1, although it is possible to determine whether the suction nozzle is clogged based on the air flow rate, a malfunction of the flow sensor may result in an erroneous measurement indicating that the air flow rate is low, and there is room for further improvement in diagnosing a flow sensor malfunction that is distinct from a clogged suction nozzle, etc.

[0005] Therefore, an object of the present disclosure is to provide a component mounting device and a method for diagnosing a pneumatic circuit that can appropriately diagnose a fault in the pneumatic circuit.

[0006] The component mounting device of the present disclosure is a component mounting device that mounts components on a substrate, and includes: a component holding head having a suction nozzle at its tip that suction-holds the component; an air flow path leading to the suction nozzle; a flow path switching unit that switches the air flow path so that it is connected to either an atmospheric opening, a positive pressure source, or a negative pressure source; a pneumatic circuit including a flow meter that measures the flow rate of air in the air flow path between the suction nozzle and the flow path switching unit; and a pneumatic circuit inspection unit that determines a fault in the pneumatic circuit based on the measurement results, by the flow meter, of the transient response of the flow rate associated with switching of the connection by the flow path switching unit.

[0007] The disclosed method for diagnosing a pneumatic circuit is a method for diagnosing a pneumatic circuit in a component mounting device that includes a component holding head having a suction nozzle at its tip for suction-holding a component, an air flow path leading to the suction nozzle, a flow path switching unit that switches the air flow path so that it is connected to either an atmospheric opening, a positive pressure source, or a negative pressure source, and a pneumatic circuit that includes a flow meter that measures the flow rate of air in the air flow path between the suction nozzle and the flow path switching unit, and determines whether there is a fault in the pneumatic circuit based on the measurement results, measured by the flow meter, of the transient response of the flow rate associated with the switching of connection by the flow path switching unit.

[0008] According to the present disclosure, a fault in a pneumatic circuit can be appropriately diagnosed.

[0009] FIG. 1 is a plan view showing the configuration of a component mounting system including a component mounting device according to an embodiment of the present disclosure; (a) a plan view showing the configuration of a main part of a component holding head included in the component mounting device according to an embodiment of the present disclosure; (b) a front view showing the configuration of a pneumatic circuit of a component holding head included in the component mounting device according to an embodiment of the present disclosure; (c) a block diagram showing the configuration of a control system of the component mounting device according to an embodiment of the present disclosure; (d) a timing diagram explaining the diagnosis of a pneumatic circuit by the component mounting device according to an embodiment of the present disclosure; (e) a timing diagram explaining another example of the diagnosis of a pneumatic circuit by the component mounting device according to an embodiment of the present disclosure;

[0010] An embodiment of the present disclosure will be described in detail below with reference to the drawings. The configurations, shapes, and the like described below are merely examples for explanatory purposes and may be modified as appropriate depending on the specifications of the component mounting system, component mounting device, component holding head, and pneumatic circuit. Corresponding elements in all drawings will be denoted by the same reference numerals, and redundant description will be omitted. In FIG. 1 and in some portions described below, two axes perpendicular to each other in a horizontal plane are shown: an X-axis in the substrate transport direction (the left-right direction in FIG. 1 ), and a Y-axis perpendicular to the substrate transport direction (the up-down direction in FIG. 1 ). In FIG. 2 and in some portions described below, a Z-axis (the up-down direction in FIG. 2B ) is shown as a height direction perpendicular to the horizontal plane.

[0011] First, the configuration of a component mounting system 1 will be described with reference to FIG. 1 . FIG. 1 is a plan view showing the configuration of a component mounting system including a component mounting device according to an embodiment of the present disclosure. The component mounting system 1 includes a component mounting device 2 and has the function of mounting components on a board to produce a mounted board. The component mounting device 2 is connected to a management computer 4 via a communication network 3. Note that the component mounting system 1 is not limited to having one component mounting device 2, and may include two or more components. In addition to its line management function, the management computer 4 has the function of determining a failure in the pneumatic circuit of the component holding head based on data acquired by the component mounting device 2.

[0012] Next, the configuration of the component mounting device 2 will be described with reference to FIGS. 1 to 3. FIG. 2 shows (a) a plan view and (b) a front view illustrating the configuration of a main part of a component holding head provided in a component mounting device according to an embodiment of the present disclosure. FIG. 3 is a block diagram illustrating the configuration of a pneumatic circuit of the component holding head provided in a component mounting device according to an embodiment of the present disclosure. In FIG. 1, the component mounting device 2 has the function of performing a component mounting operation in which components supplied from a component supply unit are mounted on a substrate. A substrate transport mechanism 6 is disposed along the X-axis in the center of the base 5. The substrate transport mechanism 6 transports a substrate B transported from upstream to a mounting operation position, positions it, and holds it. The substrate transport mechanism 6 also transports the substrate B downstream after the component mounting operation has been completed.

[0013] Component supply units 7 are arranged on both sides of the board transport mechanism 6 (front and rear directions along the Y axis). Each component supply unit 7 has multiple tape feeders 8 arranged along the X axis. Each tape feeder 8 pitch-feeds a component tape, on which pockets for storing components are formed, from the outside of the component supply unit 7 toward the board transport mechanism 6 (the tape feed direction), thereby supplying components to a component supply position from which the components are picked up by a component holding head 11, which will be described below.

[0014] 1, a Y-axis table 9 equipped with a linear drive mechanism is arranged along the Y-axis on both ends of the upper surface of the base 5 in the X-axis direction. A beam 10 similarly equipped with a linear drive mechanism is connected to the Y-axis table 9 so as to be movable along the Y-axis. The beam 10 is arranged along the X-axis. A component holding head 11 is attached to the beam 10 via a plate 10a so as to be movable along the X-axis.

[0015] 2, the component holding head 11 is detachably attached to the plate 10a. The component holding head 11 has a plurality of (here, 16) component mounting sections 12. The lower end of each of the component mounting sections 12 is provided with a nozzle holder 12a to which a suction nozzle 13 is attached, which vacuum-sucks and holds a component. Each component mounting section 12 is equipped with an elevator motor 12b that raises and lowers the nozzle holder 12a along the Z axis, and an air pressure circuit 12c that supplies negative pressure, positive pressure, or atmospheric pressure to the suction nozzle 13 attached to the nozzle holder 12a. In this way, the component holding head 11 has the suction nozzle 13, which vacuum-sucks and holds a component, at the tip of the component holding head 11.

[0016] 1 , the Y-axis table 9 and the beam 10 constitute a head moving mechanism 14 that moves the component holding head 11 along the X-axis and the Y-axis. The head moving mechanism 14 and the component holding head 11 perform a mounting turn in which they vacuum-suck and pick up components from the tape feeder 8 arranged in the component supply unit 7 using the suction nozzle 13 attached to the nozzle holder 12a of the component mounting unit 12, and mount the components at the mounting position on the board B positioned by the board transport mechanism 6.

[0017] 1, a component recognition camera 15 is disposed between the component supply unit 7 and the board transport mechanism 6. When the component holding head 11 that has picked up a component from the component supply unit 7 moves above the component recognition camera 15, the component recognition camera 15 captures an image of the component held by the component holding head 11 to recognize the holding posture of the component. A head camera 16 is attached to the plate 10a to which the component holding head 11 is attached. The head camera 16 moves integrally with the component holding head 11.

[0018] As the component holding head 11 moves, the head camera 16 moves above the board B positioned by the board transport mechanism 6, and captures an image of a board mark (not shown) provided on the board B to recognize the position of the board B. When the component holding head 11 mounts components on the board B, the mounting position is corrected taking into account the component recognition results from the component recognition camera 15 and the board position recognition results from the head camera 16.

[0019] 1, a touch panel 17 operated by the worker is installed in front of the component mounting device 2 at a position where the worker works. The touch panel 17 displays various information on its display unit, and the worker inputs data and operates the component mounting device 2 using operation buttons and the like displayed on the display unit.

[0020] Next, the configuration of the air pressure circuit 12c that supplies negative pressure, positive pressure, or atmospheric pressure to the suction nozzle 13 attached to the nozzle holder 12a of the component mounting unit 12 will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram that schematically shows the component mounting unit 12.

[0021] The air pressure circuit 12c includes an air flow path 20 leading to the suction nozzle 13, a flow path switching unit 21, and a flow rate measuring device 22 that measures the flow rate of air in the air flow path 20 between the suction nozzle 13 and the flow path switching unit 21. A filter 23 is disposed in the air flow path 20 between the suction nozzle 13 and the flow rate measuring device 22 to collect dust and other particles sucked in together with the air from the suction nozzle 13 during vacuum suction. That is, the filter 23 is disposed inside the component holding head 11.

[0022] 3, the flow path switching unit 21 includes a first valve 24 and a second valve 25 controlled by a control device 30 (FIG. 4) included in the component mounting device 2. The first valve 24 and the second valve 25 are two-input, one-output air valves. The first valve 24 includes an output port P1, a first input port P2, and a second input port P3. The second valve 25 includes an output port P4, a first input port P5, and a second input port P6.

[0023] 3, the first input port P2 of the first valve 24 is connected to a negative pressure source 26, and the second input port P3 is connected to an output port P4 of the second valve 25. The first input port P5 of the second valve 25 is connected to a positive pressure source 27, and the second input port P6 is connected to an atmosphere opening 28. The output port P1 of the first valve 24 is in communication with the flow rate measuring device 22 via the air flow path 20.

[0024] When the control device 30 switches the first valve 24 to the OFF state using a valve signal, the output port P1 is connected to the first input port P2, and the output port P1 is connected to the negative pressure source 26. In other words, the air flow path 20 is connected to the negative pressure source 26. When the control device 30 switches the first valve 24 to the ON state using a valve signal, the output port P1 is connected to the second input port P3, and is connected to the output port P4 of the second valve 25.

[0025] 3 , when the first valve 24 is in the ON state and the control device 30 switches the second valve 25 to the ON state using a valve signal, the output port P4 is connected to the first input port P5, and the output port P1 of the first valve 24 is connected to the positive pressure source 27. That is, the air flow path 20 is connected to the positive pressure source 27. Also, when the first valve 24 is in the ON state and the control device 30 switches the second valve 25 to the OFF state using a valve signal, the output port P4 is connected to the second input port P6, and the output port P1 of the first valve 24 is connected to the atmosphere opening 28. That is, the air flow path 20 is connected to the atmosphere opening 28.

[0026] In this way, the flow path switching unit 21 switches the air flow path 20 so that it is connected to either the atmosphere opening 28, the positive pressure source 27, or the negative pressure source 26. Note that, although the above description has been given using an example in which the flow path switching unit 21 is configured with two two-input, one-output air valves, the flow path switching unit 21 is not limited to this configuration. For example, the flow path switching unit 21 may be configured to use one three-input, one-output air valve and to switch and connect the air flow path 20 to the atmosphere opening 28, the positive pressure source 27, or the negative pressure source 26.

[0027] Next, referring to Fig. 4, the configuration of the control system of the component mounting device 2 will be described, focusing on the function of diagnosing the pneumatic circuit 12c of the component holding head 11. Fig. 4 is a block diagram showing the configuration of the control system of the component mounting device according to one embodiment of the present disclosure. The component mounting device 2 includes a control device 30, a substrate conveying mechanism 6, a tape feeder 8, a component holding head 11, a head moving mechanism 14, a component recognition camera 15, a head camera 16, and a touch panel 17. The component holding head 11 includes a plurality of component mounting units 12 each including an elevation motor 12b, a flow rate measuring device 22, a first valve 24, and a second valve 25.

[0028] The control device 30 includes a control memory unit 31, an on-board control unit 32, and an air pressure circuit inspection unit 33. The control memory unit 31 is a storage device, and stores on-board data 34, flow rate measurement condition data 35, flow rate measurement results 36, judgment threshold data 37, and the like.

[0029] 4, the mounting data 34 stores various information for each type of mounting board, such as the type of component to be mounted on board B, the mounting position (XY coordinates) on board B, and the type of suction nozzle 13 that vacuum-sucks the component. Based on the mounting data 34, the mounting control unit 32 performs a component mounting operation by raising and lowering the suction nozzle 13 attached to the component mounting unit 12 of the component holding head 11 to pick up the component supplied by the tape feeder 8 of the component supply unit 7 and mount it at the mounting position on board B.

[0030] 4, the flow rate measurement condition data 35 defines the timing for switching (turning ON / OFF) the first valve 24 and the second valve 25 (flow path switching unit 21) of the pneumatic circuit 12c to diagnose a fault in the pneumatic circuit, and the timing (first time ΔT1 to fifth time ΔT5) for measuring the flow rate of air flowing through the air flow path 20 (hereinafter referred to as "air flow rate Q") by the flow meter 22 (FIGS. 5 and 6). The judgment threshold data 37 defines the thresholds (first threshold α to fourth threshold δ) used by the pneumatic circuit inspection unit 33 to judge a fault in the pneumatic circuit 12c (FIGS. 5 and 6).

[0031] The pneumatic circuit inspection unit 33 controls the first valve 24 and the second valve 25 based on the flow rate measurement condition data 35, and causes the flow rate meter 22 to measure the air flow rate Q. The measured air flow rate Q is stored in the control memory unit 31 as a flow rate measurement result 36. The pneumatic circuit inspection unit 33 also determines whether there is a fault in the pneumatic circuit 12c based on the measurement result of the transient response of the air flow rate Q that accompanies switching of the connection by the flow path switching unit 21, which is included in the flow rate measurement result 36.

[0032] Next, a specific example of the diagnosis of the pneumatic circuit 12c by the pneumatic circuit inspection unit 33 will be described with reference to FIG. 5 . FIG. 5 is a timing diagram illustrating the diagnosis of the pneumatic circuit by the component mounting device according to an embodiment of the present disclosure. Here, an example will be described in which the air flow path 20 is connected to the atmosphere opening 28 (time T0), and then the flow path switching unit 21 connects the air flow path 20 to the negative pressure source 26 at time T1, and then connects the air flow path 20 to the atmosphere opening 28 at time T3, thereby diagnosing the pneumatic circuit 12c. The diagnosis of the pneumatic circuit 12c is performed with the suction nozzle 13 not attached to the nozzle holder 12a. This makes it possible to eliminate the influence (misdiagnosis) of a clogged suction nozzle 13.

[0033] First, referring to Figure 5, the air flow rate Q when the pneumatic circuit 12c is normal will be described. When the air flow path 20 is connected to the atmosphere opening 28 (time T0), no pressure difference occurs between the opening of the nozzle holder 12a and the air flow path 20, so the air flow rate Q measured by the flow rate meter 22 is "0 (zero)." When the air flow path 20 is connected to the negative pressure source 26 at time T1, a pressure difference occurs between the opening of the nozzle holder 12a and the air flow path 20, and the air that flows in from the opening of the nozzle holder 12a is measured by the flow rate meter 22 as the air flow rate Q.

[0034] 5, the pneumatic circuit inspection unit 33 measures the first flow rate Q1 at time T2, when a first time ΔT1 (T2-T1) has elapsed since time T1, when air inflow began, and the transient response of the air flow rate Q has sufficiently converged and transitioned to a steady state. The pneumatic circuit inspection unit 33 then determines whether the absolute value of the first flow rate Q1 is equal to or greater than a first threshold value α. If the absolute value of the first flow rate Q1 is equal to or greater than the first threshold value α (|Q1|≧α), the pneumatic circuit inspection unit 33 determines that the pneumatic circuit 12c is normal.

[0035] Here, the first threshold value α is set to a value smaller than the air flow rate Q when the air flow path 20 of the normal pneumatic circuit 12c is connected to the negative pressure source 26 and in a steady state, and larger than the air flow rate Q when the air flow path 20 of the pneumatic circuit 12c that has become abnormal due to a clogged filter, as described below, is connected to the negative pressure source 26 and in a steady state.

[0036] Next, referring to Figure 5, the air flow rate Q of the pneumatic circuit 12c when the filter 23 is clogged with dust or the like, impairing the air flow (filter clogging) will be described. When the filter 23 is clogged, the absolute value of the first flow rate Q1 measured at time T2 becomes smaller than the first threshold value α (|Q1| < α). When the air flow path 20 is connected to the atmosphere opening 28 at time T3, the pressure difference between the opening of the nozzle holder 12a and the air flow path 20 disappears, and the transient response a of the air flow rate Q sufficiently converges and transitions to a steady state, so that the air flow rate Q measured by the flow rate meter 22 becomes "0 (zero)."

[0037] However, in transient response a, an undershoot occurs in which air flows out from the opening of nozzle holder 12a for the following reason: If filter 23 is clogged, even when flow path switching unit 21 connects air flow path 20 to atmosphere opening 28, the pressure inside air flow path 20 remains low for a certain period of time, so it takes time for the air flow path 20 to be filled with air to its full volume, and the pressure changes suddenly, causing an undershoot.

[0038] 5, the pneumatic circuit inspection unit 33 measures the second flow rate Q2 at time T4, which is a second time ΔT2 (T4 - T3) after time T3 when the air flow path 20 is connected to the atmosphere opening 28. In other words, time T4 is set as the time when the air flow rate Q is in a state of transient response a. Furthermore, the pneumatic circuit inspection unit 33 measures the third flow rate Q3 at time T5, which is a third time ΔT3 (T5 - T3) after time T3 when the air flow path 20 is connected to the atmosphere opening 28, when the transient response a of the air flow rate Q has sufficiently converged and transitioned to a steady state.

[0039] The pneumatic circuit inspection unit 33 then determines whether the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 (|Q2-Q3|) is equal to or greater than the second threshold value β. If the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is equal to or greater than the second threshold value β (|Q2-Q3|≧β), the pneumatic circuit inspection unit 33 determines that the filter 23 is clogged.

[0040] Here, the second threshold value β is set to a value that is smaller than the air flow rate Q of the undershoot that occurs in the transient response a when the air flow path 20 of the pneumatic circuit 12c with a clogged filter 23 is connected to the atmosphere opening 28, and is larger than the air flow rate Q indicated by a faulty flow rate measuring device 22 (sensor) described below.

[0041] Next, referring to Figure 5, the air flow rate Q measured in the pneumatic circuit 12c in which the flow rate measuring device 22 (sensor) has failed will be described. When the flow rate measuring device 22 has failed, it may output a signal indicating an air flow rate Q that is smaller than the actual air flow rate Q, or the response speed may decrease, making it impossible to measure the transient response a. When the flow rate measuring device 22 has failed, the absolute value of the first flow rate Q1 measured at time T2 becomes smaller than the first threshold value α (|Q1| < α).

[0042] Furthermore, the second flow rate Q2 measured at time T4 cannot handle the undershoot and outputs a signal indicating a small air flow rate Q. Therefore, the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 (|Q2-Q3|) becomes smaller than the second threshold value β (|Q2-Q3|<β), and the air pressure circuit inspection unit 33 determines that the flow rate measuring device 22 (sensor) is faulty.

[0043] In this way, the flow rate measuring instrument 22 measures the first flow rate Q1 when a first time ΔT1 has elapsed (time T2) since the flow path switching unit 21 switched the connection of the air flow path 20 from the atmosphere opening 28 to the negative pressure source 26 (time T1) when the air flow path 20 is connected to the atmosphere opening 28, thereafter measures the second flow rate Q2 during the transient response a when a second time ΔT2 has elapsed (time T4) since the flow path switching unit 21 switched the connection of the air flow path 20 to the atmosphere opening 28 (time T3), and further measures the third flow rate Q3 when a third time ΔT3 longer than the second time ΔT2 has elapsed (time T5).

[0044] The pneumatic circuit inspection unit 33 determines that the pneumatic circuit 12c is normal if the absolute value of the first flow rate Q1 is equal to or greater than a first threshold value α (|Q1|≧α). The pneumatic circuit inspection unit 33 also determines that the filter 23 in the component holding head 11 is clogged if the absolute value of the first flow rate Q1 is smaller than the first threshold value α (|Q1|<α) and the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is equal to or greater than a second threshold value β (|Q2-Q3|≧β). The pneumatic circuit inspection unit 33 also determines that the flow meter 22 (sensor) is faulty if the absolute value of the first flow rate Q1 is smaller than the first threshold value (|Q1|<α) and the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is smaller than the second threshold value β (|Q2-Q3|<β).

[0045] Next, referring to FIG. 6 , another example of the diagnosis of the pneumatic circuit 12c by the pneumatic circuit inspection unit 33 will be described. FIG. 6 is a timing diagram illustrating another example of the diagnosis of the pneumatic circuit by the component mounting device according to an embodiment of the present disclosure. In this example, the diagnosis of the pneumatic circuit 12c shown in FIG. 5 is different in that the pneumatic circuit inspection unit 33 determines a fault in the pneumatic circuit 12c based on a transient response b of the air flow rate Q immediately after the connection of the air flow path 20 is switched from the atmosphere opening 28 to the negative pressure source 26. Here, an example will be described in which the air flow path 20 is connected to the atmosphere opening 28 (time T6), and then the flow path switching unit 21 connects the air flow path 20 to the negative pressure source 26 at time T7, and then connects the air flow path 20 to the atmosphere opening 28 at time T10, and then the diagnosis of the pneumatic circuit 12c is performed.

[0046] 6, the air flow rate Q of the pneumatic circuit 12c when the filter 23 is clogged with dust or the like and the air flow is poor (filter clogged) will be described. When the air flow path 20 is connected to the atmosphere opening 28 (time T6), the air flow rate Q measured by the flow rate meter 22 is "0 (zero)." When the air flow path 20 is connected to the negative pressure source 26 at time T7, the air flowing in from the opening of the nozzle holder 12a is measured as the air flow rate Q by the flow rate meter 22.

[0047] In transient response b, in which air flows in through the opening of nozzle holder 12a, an overshoot occurs, in which a large amount of air temporarily flows in, for the following reason: Before the air flows in, filter 23 is in a state in which dust and the like are gently trapped. When air flows in, dust collects in the holes of filter 23, and the air encounters a large resistance as it passes through filter 23. It takes time for the air flow path 20 to be filled with air to its volume, and an overshoot occurs due to a sudden change in pressure.

[0048] 6, the pneumatic circuit inspection unit 33 measures the fourth flow rate Q4 at time T8, when a fourth time ΔT4 (T8-T7) has elapsed since time T7 when the air inflow started and the state is transient response b. Furthermore, the pneumatic circuit inspection unit 33 measures the fifth flow rate Q5 at time T9, when a fifth time ΔT5 (T9-T7) has elapsed since time T7 when the air flow path 20 is connected to the negative pressure source 26 and the transient response b has sufficiently converged and transitioned to a steady state.

[0049] The pneumatic circuit inspection unit 33 determines whether the absolute value of the fifth flow rate Q5 is equal to or greater than a third threshold value γ. Here, the third threshold value γ is set to a value that is smaller than the air flow rate Q when the air flow path 20 of the normal pneumatic circuit 12c is connected to the negative pressure source 26 and in a steady state, and is larger than the air flow rate Q when the air flow path 20 of the pneumatic circuit 12c that has become abnormal due to a clogged filter is connected to the negative pressure source 26 and in a steady state.

[0050] 6, if the absolute value of the fifth flow rate Q5 is smaller than the third threshold value γ (|Q5|<γ), the pneumatic circuit inspection unit 33 determines whether the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 (|Q4-Q5|) is equal to or greater than the fourth threshold value δ. If the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is equal to or greater than the fourth threshold value δ (|Q4-Q5|≧δ), the pneumatic circuit inspection unit 33 determines that the filter 23 is clogged.

[0051] Here, the fourth threshold value δ is set to a value that is smaller than the air flow rate Q of the overshoot that occurs in the transient response b when the connection of the air flow path 20 of the pneumatic circuit 12c in which the filter 23 is clogged is switched from the atmosphere opening 28 to the negative pressure source 26, and is larger than the air flow rate Q indicated by the faulty flow rate measuring device 22 (sensor).

[0052] Next, referring to Figure 6, the air flow rate Q measured in the pneumatic circuit 12c in which the flow rate measuring device 22 (sensor) has failed will be described. Due to the failure of the flow rate measuring device 22, the absolute value of the fifth flow rate Q5 measured at time T9 becomes smaller than the third threshold value γ (|Q5| < γ). Furthermore, the fourth flow rate Q4 measured at time T8 cannot accommodate the overshoot, and a signal indicating a small air flow rate Q is output. Therefore, the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 (|Q4 - Q5|) becomes smaller than the fourth threshold value δ (|Q4 - Q5| < δ), and the pneumatic circuit inspection unit 33 determines that the flow rate measuring device 22 (sensor) has failed.

[0053] In this way, the flow meter 22 measures the fourth flow rate Q4 during the transient response b when a fourth time ΔT4 has elapsed (time T8) after the flow path switching unit 21 switches the connection of the air flow path 20 from the atmosphere opening 28 to the negative pressure source 26, when the air flow path 20 is connected to the atmosphere opening 28, and then measures the fifth flow rate Q5 when a fifth time ΔT5 has elapsed (time T9), which is longer than the fourth time ΔT4.

[0054] The pneumatic circuit inspection unit 33 determines that the pneumatic circuit 12c is normal if the absolute value of the fifth flow rate Q5 is equal to or greater than the third threshold γ (|Q5|≧γ). The pneumatic circuit inspection unit 33 also determines that the filter 23 in the component holding head 11 is clogged if the absolute value of the fifth flow rate Q5 is smaller than the third threshold γ (|Q5|<γ) and the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is equal to or greater than the fourth threshold δ (|Q4-Q5|≧δ). The pneumatic circuit inspection unit 33 also determines that the flow meter 22 (sensor) is faulty if the absolute value of the fifth flow rate Q5 is smaller than the third threshold γ (|Q5|<γ) and the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is smaller than the fourth threshold δ (|Q4-Q5|<δ).

[0055] 5 and 6 have been described with reference to an example in which the air flow path 20 is connected to the negative pressure source 26, but when the air flow path 20 is connected to the positive pressure source 27, the flow path is the same as in the case of the negative pressure source 26 except that the direction of air flow through the air flow path 20 is reversed, and detailed description thereof will be omitted. The first threshold value α, the second threshold value β, the third threshold value γ, and the fourth threshold value δ may be set to values ​​adapted to the positive pressure source 27 that are different from those in the case of the negative pressure source 26.

[0056] Next, a method for diagnosing the pneumatic circuit 12c in the component mounting device 2 will be described with reference to Fig. 5 and following the flow chart in Fig. 7. Fig. 7 is a flow chart of a method for diagnosing a pneumatic circuit according to an embodiment of the present disclosure. Here, an example will be described in which the connection of the air flow path 20 is switched between the atmosphere opening 28 and the negative pressure source 26. Note that the same applies to the case in which the connection of the air flow path 20 is switched between the atmosphere opening 28 and the positive pressure source 27, and detailed description thereof will be omitted.

[0057] First, at time T1, the flow path switching unit 21 switches the connection of the air flow path 20 from the atmosphere opening 28 to the negative pressure source 26 (ST1: negative pressure switching step). Next, the flow rate meter 22 measures the first flow rate Q1 when a first time ΔT1 has elapsed from time T1 (time T2) (Yes in ST2) (ST3: first flow rate measurement step).

[0058] 7, the pneumatic circuit inspection unit 33 then determines whether the absolute value of the first flow rate Q1 is equal to or greater than the first threshold value α (ST4: first threshold value determination step). If the absolute value of the first flow rate Q1 is equal to or greater than the first threshold value α (Yes in ST4) (|Q1|≧α), the pneumatic circuit inspection unit 33 determines that the pneumatic circuit 12c is normal (ST13: normality determination step). If the absolute value of the first flow rate Q1 is smaller than the first threshold value α (No in ST4) (|Q1|<α), the connection of the air flow path 20 is switched from the negative pressure source 26 to the atmosphere opening 28 at time T3 (ST5: atmospheric pressure switching step).

[0059] Next, the flow rate meter 22 measures the second flow rate Q2 during the transient response a when a second time ΔT2 has elapsed since time T3 (time T4) (Yes in ST6) (ST7: second flow rate measurement step). Next, the flow rate meter 22 measures the third flow rate Q3 when a third time ΔT3 has elapsed since time T3 (time T5) (Yes in ST8) (ST9: third flow rate measurement step).

[0060] 7, the pneumatic circuit inspection unit 33 then determines whether the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is equal to or greater than a second threshold value β (ST10: second threshold value determination step). If the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is equal to or greater than the second threshold value β (Yes in ST10) (|Q2-Q3|≧β), the pneumatic circuit inspection unit 33 determines that the filter 23 in the component holding head 11 is clogged (ST11: filter clog determination step). If the absolute value of the difference between the second flow rate Q2 and the third flow rate Q3 is smaller than the second threshold value β (No in ST10) (|Q2-Q3|<β), the pneumatic circuit inspection unit 33 determines that the flow measuring device 22 is faulty (ST12: sensor fault determination step).

[0061] In this way, the method for diagnosing the pneumatic circuit determines whether there is a fault in the pneumatic circuit 12c (ST4, ST10) based on the measurement results (first flow rate Q1 to third flow rate Q3) by the flow rate measuring device 22 of the transient response a of the air flow rate Q that accompanies connection switching by the flow path switching unit 21. By determining whether there is a fault based on the transient response a of the air flow rate Q that accompanies switching from negative pressure (positive pressure) to atmospheric pressure, it is possible to identify the location of the fault in the pneumatic circuit 12c in a short period of time.

[0062] Next, another example of a method for diagnosing the pneumatic circuit 12c in the component mounting device 2 will be described with reference to FIG. 6 and following the flow chart in FIG. 8. FIG. 8 is a flow chart of another example of a method for diagnosing the pneumatic circuit according to an embodiment of the present disclosure. Here, an example will be described in which the connection of the air flow path 20 is switched between the atmospheric opening 28 and the negative pressure source 26. Note that the same applies to the case in which the connection of the air flow path 20 is switched between the atmospheric opening 28 and the positive pressure source 27, and a detailed description thereof will be omitted. Below, the same steps as those in the method for diagnosing the pneumatic circuit 12c shown in FIG. 7 are designated by the same reference numerals, and a detailed description thereof will be omitted.

[0063] First, the negative pressure switching step (ST1) is executed. That is, at time T7, the flow path switching unit 21 switches the connection of the air flow path 20 from the atmosphere opening 28 to the negative pressure source 26. Next, the flow meter 22 measures a fourth flow rate Q4 during a transient response b (time T8) when a fourth time ΔT4 has elapsed since time T7 (Yes in ST21) (ST22: fourth flow rate measurement step). Next, the flow meter 22 measures a fifth flow rate Q5 (time T9) when a fifth time ΔT5 has elapsed since time T7 (Yes in ST23) (ST24: fifth flow rate measurement step).

[0064] 8 , the pneumatic circuit inspection unit 33 then determines whether the absolute value of the fifth flow rate Q5 is equal to or greater than the third threshold value γ (ST25: third threshold value determination step). If the absolute value of the fifth flow rate Q5 is equal to or greater than the third threshold value γ (Yes in ST25) (|Q5|≧γ), the pneumatic circuit inspection unit 33 determines that the pneumatic circuit 12c is normal (ST13). If the absolute value of the fifth flow rate Q5 is smaller than the third threshold value γ (No in ST25) (|Q5|<γ), the pneumatic circuit inspection unit 33 determines whether the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is equal to or greater than the fourth threshold value δ (ST26: fourth threshold value determination step).

[0065] If the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is equal to or greater than the fourth threshold value δ (Yes in ST26) (|Q4-Q5|≧δ), the pneumatic circuit inspection unit 33 determines that the filter 23 in the component holding head 11 is clogged (ST11). If the absolute value of the difference between the fourth flow rate Q4 and the fifth flow rate Q5 is smaller than the fourth threshold value δ (No in ST26) (|Q4-Q5|<δ), the pneumatic circuit inspection unit 33 determines that the flow measuring device 22 is faulty (ST12).

[0066] In this way, in this other embodiment of the method for diagnosing a pneumatic circuit, a fault in the pneumatic circuit 12c is determined (ST25, ST26) based on the measurement results (fourth flow rate Q4 to fifth flow rate Q5) by the flow rate measuring device 22 of the transient response b of the air flow rate Q that accompanies connection switching by the flow path switching unit 21. By determining a fault based on the transient response b of the air flow rate Q that accompanies switching from atmospheric pressure to negative pressure (positive pressure), the location of the fault in the pneumatic circuit 12c can be identified in a short time.

[0067] As described above, the component mounting device 2 of this embodiment includes the component holding head 11 having the suction nozzle 13 at its tip for suction-holding a component, the air flow path 20 leading to the suction nozzle 13, the flow path switching unit 21 for switching the air flow path 20 so that it is connected to either the atmosphere opening 28, the positive pressure source 27, or the negative pressure source 26, the pneumatic circuit 12c including the flow rate meter 22 for measuring the air flow rate Q in the air flow path 20 between the suction nozzle 13 and the flow path switching unit 21, and the pneumatic circuit inspection unit 33 for determining a fault in the pneumatic circuit 12c based on the measurement results (flow rate measurement results 36) of the transient responses a, b of the air flow rate Q caused by the flow path switching unit 21, measured by the flow rate meter 22. This allows for appropriate diagnosis of a fault in the pneumatic circuit 12c.

[0068] Although the above description is of a configuration in which the pneumatic circuit inspection unit 33 is provided in the component mounting device 2, the present invention is not limited to this configuration. For example, the control computer 4 may be configured to have, among the functions of the pneumatic circuit inspection unit 33, a function for determining whether or not there is a malfunction in the pneumatic circuit 12c based on the measurement results (flow measurement results 36) from the flow meter 22. In this case, the measurement results from the flow meter 22 are transmitted from the component mounting device 2 to the control computer 4, and the control computer 4 determines whether or not there is a malfunction in the pneumatic circuit 12c.

[0069] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, alterations, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components in the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0070] The component mounting device and the diagnostic method for an air pressure circuit of the present disclosure have the effect of being able to properly diagnose a fault in an air pressure circuit, and are useful in the field of mounting components on a board.

[0071] 2 Component mounting device 11 Component holding head 12c Air pressure circuit 13 Suction nozzle 20 Air flow path 21 Flow path switching unit 22 Flow rate measuring device 23 Filter B Substrate Q Air flow rate (air flow rate) Q1 First flow rate Q2 Second flow rate Q3 Third flow rate Q4 Fourth flow rate Q5 Fifth flow rate α First threshold β Second threshold γ Third threshold δ Fourth threshold ΔT1 First time ΔT2 Second time ΔT3 Third time ΔT4 Fourth time ΔT5 Fifth time

Claims

1. A component mounting device for mounting components onto a circuit board, comprising: a component holding head having a suction nozzle at its tip for suction-holding components; an air flow path leading to the suction nozzle; a flow path switching unit for switching the air flow path so that it is connected to either an atmospheric opening, a positive pressure source, or a negative pressure source; a pneumatic circuit including a flow meter for measuring the flow rate of air in the air flow path between the suction nozzle and the flow path switching unit; and a pneumatic circuit inspection unit for determining whether there is a fault in the pneumatic circuit based on the measurement results, by the flow meter, of the transient response of the flow rate associated with the switching of connection by the flow path switching unit.

2. The component mounting device according to claim 1, wherein the flow rate measuring device measures a first flow rate when a first time has elapsed since the flow path switching unit switched the connection of the air flow path from the atmosphere opening to the positive pressure source or the negative pressure source, measures a second flow rate during a transient response when a second time has elapsed since the flow path switching unit switched the connection of the air flow path to the atmosphere opening, after measuring the first flow rate, and measures a third flow rate when a third time longer than the second time has elapsed since the flow path switching unit switched the connection of the air flow path to the atmosphere opening, and the pneumatic circuit inspection unit determines that the flow rate measuring device has failed if the absolute value of the first flow rate is smaller than a first threshold value and the absolute value of the difference between the second flow rate and the third flow rate is smaller than a second threshold value.

3. The component mounting device of claim 2, wherein the air pressure circuit inspection unit determines that a filter in the component holding head is clogged if the absolute value of the first flow rate is smaller than the first threshold value and the absolute value of the difference is equal to or greater than the second threshold value.

4. The component mounting device according to claim 2, wherein the air pressure circuit inspection unit determines that the air pressure circuit is normal when the absolute value of the first flow rate is equal to or greater than the first threshold value.

5. The component mounting device according to claim 1, wherein the flow rate measuring device measures a fourth flow rate during a transient response when a fourth time has elapsed since the flow path switching unit switched the connection of the air flow path from the atmospheric opening to the positive pressure source or the negative pressure source, and measures a fifth flow rate when a fifth time longer than the fourth time has elapsed since the flow path switching unit switched the connection of the air flow path from the atmospheric opening to the positive pressure source or the negative pressure source, and the pneumatic circuit inspection unit determines that the flow rate measuring device has failed if the absolute value of the fifth flow rate is smaller than a third threshold value and the absolute value of the difference between the fourth flow rate and the fifth flow rate is smaller than a fourth threshold value.

6. The component mounting device of claim 5, wherein the air pressure circuit inspection unit determines that a filter in the component holding head is clogged if the absolute value of the fifth flow rate is smaller than the third threshold value and the absolute value of the difference is equal to or greater than the fourth threshold value.

7. A method for diagnosing a pneumatic circuit in a component mounting device comprising: a component holding head having a suction nozzle at its tip for suction-holding a component; an air flow path leading to the suction nozzle; a flow path switching unit for switching the air flow path so that it is connected to either an atmospheric opening, a positive pressure source, or a negative pressure source; and a pneumatic circuit including a flow meter for measuring the flow rate of air in the air flow path between the suction nozzle and the flow path switching unit, wherein the method determines whether the pneumatic circuit has failed based on the measurement results, by the flow meter, of the transient response of the flow rate associated with the switching of connection by the flow path switching unit.

Images