Substrate-conveying device

Abstract

This substrate-conveying device comprises: a conveyor that conveys a substrate in a conveyance direction; a motor that operates the conveyor; a control unit that can execute conveyance processing for conveying the substrate to a predetermined stop position by the conveyor by driving the motor; and at least one detection unit that detects the upstream end and the downstream end of the substrate in the conveyance direction. When executing the conveyance processing, the control unit corrects the set output amount of the motor for moving the substrate to the stop position while the substrate is being conveyed, on the basis of the difference between the drive amount of the motor and the movement amount of the substrate that is calculated on the basis of the detection result of the detection unit.

Description

Substrate transport device

[0001] The technology disclosed in this specification relates to a substrate transport device that transports a substrate to a predetermined stopping position.

[0002] International Publication No. 2013 / 124970 discloses a substrate transport device that stops a substrate transported in a transport direction by a conveyor at a predetermined stop position. When a detector detects the upstream end of the substrate, the substrate transport device operates the conveyor by a predetermined set operation amount to stop the substrate. At this time, the substrate transport device calculates an error in the stop position based on the difference between the theoretical operation amount required for the conveyor to operate to move the substrate from the position where the detector detects the downstream end of the substrate to the stop position and the actual operation amount actually operated from the position where the detector detects the downstream end of the substrate to the stop position. The substrate transport device corrects the error by operating the conveyor again based on the calculated error.

[0003] In the technology disclosed in International Publication No. 2013 / 124970, the conveyor is operated a set amount and then stopped, and then the conveyor is operated again based on the calculated error to eliminate the error. As a result, it takes a relatively long time to accurately position the substrate at the stopping position. This specification provides a technology that enables accurate positioning of the substrate in a shorter time using a substrate transport device.

[0004] The substrate transport device disclosed in this specification includes a conveyor that transports a substrate in a transport direction, a motor that operates the conveyor, a control unit that can execute a transport process in which the conveyor transports the substrate to a predetermined stop position by driving the motor, and at least one detection unit that detects an upstream end and a downstream end of the substrate in the transport direction. When executing the transport process, the control unit corrects a set output amount of the motor for moving the substrate to the stop position while the substrate is being transported, based on a difference between a drive amount of the motor and a movement amount of the substrate calculated based on a detection result of the detection unit.

[0005] When a substrate is transported by a conveyor, relative movement between the substrate and the conveyor occurs due to vibrations of the substrate or conveyor, frictional resistance of the guide members against the substrate, inertial forces of the substrate during acceleration and deceleration, and other factors, which can cause the actual stop position to deviate from the desired stop position. That is, the substrate movement amount may deviate from the motor drive amount (conveyor movement amount). In the above-described substrate transport device, the set output amount of the motor is corrected while the substrate is being transported based on the difference between the motor drive amount and the substrate movement amount calculated based on the detection results of the detection unit. In this way, the above-described substrate transport device can correct errors in the set output amount by feeding back this difference during conveyor operation, thereby enabling accurate positioning of the substrate in a shorter time than conventional configurations.

[0006] 1 is a plan view of a component mounter according to an embodiment. A rear view of a main conveyor. A block diagram showing a control system of a component mounter. A flowchart showing an example of an operation control selection process. A flowchart showing an example of a board carry-in process. A flowchart showing an example of a first conveyance process. A flowchart showing an example of the first conveyance process. A timing chart showing the output of each board sensor and a graph showing the output of a motor in the first conveyance process. A diagram for explaining the conveyance and stopping of a board when the main conveyor is controlled by the first conveyance process. A flowchart showing an example of a second conveyance process. A flowchart showing an example of the second conveyance process. A timing chart showing the output of each board sensor and a graph showing the output of a motor in the second conveyance process. A diagram for explaining the conveyance and stopping of a board when the main conveyor is controlled by the second conveyance process. A flowchart showing an example of a third conveyance process. A flowchart showing an example of the third conveyance process. A timing chart showing the output of a board sensor and a graph showing the output of a motor in the third conveyance process. A diagram for explaining the conveyance and stopping of a board when the main conveyor is controlled by the third conveyance process.

[0007] The main features of the embodiments described below are listed below. Note that the technical elements described below are independent technical elements that exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0008] In one embodiment of the present technology, when performing a transport process, the control unit may calculate, based on the length of the substrate, a theoretical output amount of the motor for the substrate to move a distance between a first position where the detection unit detects the upstream end or the downstream end, and a second position where the detection unit detects the upstream end or the downstream end, the second position being different from the first position; when the detection unit detects the upstream end or the downstream end of the substrate, calculate the set output amount based on the theoretical output amount; detect an actual output amount of the motor when the substrate actually moves a distance between the first position and the second position; and correct the set output amount based on a difference between the theoretical output amount and the actual output amount while transporting the substrate.

[0009] In this configuration, the theoretical output amount for the board to travel a predetermined distance to the stop position (the distance between the first position and the second position) is calculated, and by comparing this predetermined distance with the actual output amount when the board actually travels, it is possible to predict and calculate the deviation in the theoretical output amount due to the relative movement between the board and the conveyor. Therefore, the set output amount can be appropriately corrected based on the difference between the theoretical output amount and the actual output amount.

[0010] In an embodiment of the present technology, the detection unit may include an upstream detection unit provided upstream in the transport direction and a downstream detection unit provided downstream of the upstream detection unit. When a length of the substrate in the transport direction is shorter than a distance between the upstream detection unit and the downstream detection unit, the first position may be a position where the upstream detection unit detects the upstream end of the substrate, and the second position may be a position where the downstream detection unit detects the downstream end of the substrate. When performing the transport process, the control unit may calculate the set output amount of the motor for moving the substrate from the first position to the stop position based on the theoretical output amount when the upstream detection unit detects the upstream end of the substrate.

[0011] In this configuration, two detectors spaced apart are used to calculate the difference between the theoretical output and the actual output, allowing for accurate calculation of the deviation of the theoretical output from the actual output.

[0012] In one embodiment of the present technology, the control unit may calculate the length of the substrate based on the amount of output of the motor between when the upstream detection unit detects the downstream end of the substrate and when it detects the upstream end.

[0013] In this configuration, the length of the substrate can be calculated while the substrate is being transported, so there is no need to know information about the length of the substrate in advance.

[0014] In an embodiment of the present technology, the detection unit may include an upstream detection unit provided upstream in the transport direction and a downstream detection unit provided downstream of the upstream detection unit. When a length of the substrate in the transport direction is longer than a distance between the upstream detection unit and the downstream detection unit, the first position may be a position where the upstream detection unit detects the downstream end of the substrate, and the second position may be a position where the downstream detection unit detects the downstream end of the substrate. When performing the transport process, the control unit may calculate the set output amount of the motor for moving the substrate from the first position to the stop position based on the theoretical output amount when the upstream detection unit detects the downstream end of the substrate.

[0015] In this configuration, two detectors spaced apart are used to calculate the difference between the theoretical output and the actual output, allowing for accurate calculation of the deviation of the theoretical output from the actual output.

[0016] In one embodiment of the present technology, the substrate transport device may include a single detector configured to detect the upstream end and the downstream end of the substrate in the transport direction. The first position may be a position where the detector detects the downstream end of the substrate, and the second position may be a position where the detector detects the upstream end of the substrate. When performing the transport process, the controller may calculate, based on the theoretical output amount, the set output amount of the motor for moving the substrate from the first position to the stop position when the detector detects the downstream end of the substrate.

[0017] In this configuration, the difference between the theoretical output amount and the actual output amount is calculated using only a single detector, which simplifies the device configuration and reduces costs.

[0018] In one embodiment of the present technology, the motor may be a motor that does not include an encoder that detects the rotation angle of the motor.

[0019] In the substrate transport device of the present technology, the upstream and downstream ends of the substrate (i.e., the position of the substrate) are detected by the detection unit, so that even if the motor does not have an encoder, the set output amount can be appropriately corrected and the substrate can be accurately positioned.

[0020] (First Embodiment) A component mounter 10 according to a first embodiment will be described with reference to the drawings. The component mounter 10 is a device that mounts components onto a board 2. The component mounter 10 is also called an electronic component placement device or a chip mounter. Typically, the component mounter 10 is installed alongside other board work machines such as a solder printer and a board inspection machine, forming a continuous mounting line.

[0021] As shown in FIG. 1, the component mounter 10 includes a board conveyor group 12, a board holding device 14, component supply devices 16 and 18, a mounting device 20, a reference mark imaging device 22, a component imaging device 24, and a control device 26.

[0022] The board conveyor group 12 includes a conveyor 30 for carrying the board 2 into the mounter 10, a main conveyor 32 for positioning the board 2 within the mounter 10, and a conveyor 34 for carrying the board 2 out of the mounter 10. The conveyors 30, 32, and 34 are all belt conveyors. As shown in FIG. 2 , the main conveyor 32 includes a pair of endless conveyor belts 36 and a belt circulation device 38. The belt circulation device 38 includes drive pulleys 44 rotatably attached to the inner surfaces of the side frames 40 and 42, which face each other, a plurality of guide pulleys 46, and a motor 50 for driving each of the drive pulleys 44 of the side frames 40 and 42. The conveyors 30 and 34 have the same configuration as the main conveyor 32 (the conveyor belt 36 and the belt circulation device 38).

[0023] The pulleys 44 and 46 are timing pulleys. The conveyor belt 36 is a timing belt. The pair of conveyor belts 36 are rotated simultaneously by the belt rotation device 38, so that the substrate 2 is guided on both sides in the width direction (the y-axis direction in FIG. 1) by the guide rails 56 and transported along the transport direction (the positive x-axis direction in FIG. 1). The motor 50 is a pulse motor that does not have an encoder that detects the rotation angle of the motor.

[0024] 1, the main conveyor 32 is provided with board sensors 60, 62, and 64 in the transport direction of the boards 2. Board sensor 60 is provided at the upstream end of the main conveyor 32 in the transport direction. Board sensor 62 is provided at the downstream end of the main conveyor 32 in the transport direction. Board sensor 64 is provided between board sensors 60 and 62 in the transport direction. In this embodiment, board sensor 64 is provided upstream of the center of the main conveyor 32 in the transport direction.

[0025] In this embodiment, each of the board sensors 60, 62, 64 is configured as a transmission type photoelectric sensor, and includes a light-emitting unit 68 and a light-receiving unit 70 that are provided facing each other and spaced apart in the width direction, as shown in Fig. 1. Each of the board sensors 60, 62, 64 outputs OFF when the light-receiving unit 70 receives light from the light-emitting unit 68, and outputs ON when the light is not received.

[0026] As shown in Fig. 1, the substrate holding device 14 is provided at the center in the transport direction of the main conveyor 32. As shown in Fig. 2, the substrate holding device 14 includes a substrate support device 80 and a clamp member 82. The substrate support device 80 supports the rear surface of the substrate 2 from below using support pins 84, and holds the substrate 2 in a horizontal position.

[0027] As shown in FIG. 1 , the placement device 20 includes a placement head 100 and a head moving device 102. The head moving device 102 includes an x-axis moving device 104 and a y-axis moving device 106, and moves the placement head 100 to any position within the xy plane. The x-axis moving device 104 includes an x-axis slider 110 and an x-axis slider moving device 112. The x-axis slider moving device 112 includes a motor 114 and a feed screw mechanism 118 including a ball screw 116 and a nut (not shown). In this embodiment, the y-axis moving device 106 is provided on the x-axis slider 110 and includes a y-axis slider 120 and a y-axis slider moving device 122. The y-axis slider moving device 122 includes a motor 124 and a feed screw mechanism (not shown). The motors 114 and 124 are configured as servo motors or pulse motors with encoders, or the like. The mounting head 100 holds electronic components with a suction nozzle and is mounted on a y-axis slider 120. The mounting head 100 moves the suction nozzle in the z direction to move the suction nozzle closer to and further away from the component supply devices 16, 18 and the board 2. The mounting head 100 can use the suction nozzle to pick up electronic components from the component supply devices 16, 18 and place the electronic components picked up by the suction nozzle onto the board 2.

[0028] Each of the imaging devices 22, 24 has a camera such as a CCD camera or a CMOS camera. The fiducial mark imaging device 22 is mounted on the y-axis slider 120. The fiducial mark imaging device 22 is moved to any position in the xy plane by the head moving device 102 and images a fiducial mark 130 provided on the surface of the board 2. The component imaging device 24 is mounted on the y-axis slider 120. The component imaging device 24 images an electronic component sucked by a suction nozzle of the mounting head 100.

[0029] The control device 26 is configured using a computer including a CPU 27 and a memory 28. The control device 26 controls the operation of each part of the component mounter 10 based on a production program transmitted from a higher-level management device (not shown). As shown in FIG. 3 , the control device 26 is connected to and controls the operation of the board conveyor group 12, the board holding device 14, the component supply device 16, the mounting device 20, the reference mark imaging device 22, the component imaging device 24, and the board sensors 60, 62, and 64. The memory 28 stores a first counter 80, a second counter 82, and a flag F1. The first counter 80 and the second counter 82 count the number of pulses output by the motor 50 of the main conveyor 32. The flag F1 changes from "0" to "1" when the upstream or downstream end of the board 2 is detected by the board sensor 60.

[0030] Next, the operation control of the main conveyor 32 will be described. The conveyors 30, 32, and 34 can transport the board 2 in both forward and reverse directions by changing the rotation direction of the conveyor belt 36. Here, as described above, a case will be described in which the board 2 is transported in the positive direction of the x-axis in FIG. 1 (from left to right in FIG. 1). In this case, the conveyor 30 functions as an input conveyor, the conveyor 34 functions as an output conveyor, the board sensor 60 functions as an upstream sensor, and the board sensor 64 functions as a downstream sensor, and the board sensor 62 detects the output of the board 2 from the main conveyor 32 to the output conveyor 34. Hereinafter, the board sensor 60 will be referred to as the upstream sensor 60, and the board sensor 64 will be referred to as the downstream sensor 64.

[0031] First, the CPU 27 of the control device 26 executes the operation control selection process shown in FIG. 4 prior to the start of a series of mounting of electronic components onto the board 2. In S10, the CPU 27 determines whether the length between the upstream and downstream ends of the board 2 in the transport direction for the board 2 being carried in is shorter than the inter-sensor distance between the upstream sensor 60 and the downstream sensor 64. The production program transmitted from the management device describes the type and size of the board 2 to be produced. The inter-sensor distance is also known. Therefore, the CPU 27 determines whether the length of the board 2 is shorter than the inter-sensor distance based on the production program.

[0032] If the CPU 27 determines that the length of the board 2 is shorter than the distance between the sensors (YES in S10), it selects in S12 a first transport process as a process for transporting the board 2 by the main conveyor 32 when the board 2 is carried in, and stores this in the memory 28. On the other hand, if the CPU 27 determines that the length of the board 2 is longer than the distance between the sensors (NO in S10), it selects in S14 a second transport process as a process for transporting the board 2 by the main conveyor 32 when the board 2 is carried in, and stores this in the memory 28. The order in which the board sensors 60, 64 detect the board edges differs depending on whether the length of the board 2 is shorter than the distance between the sensors. Therefore, in the operation control selection process, one of two types of operation control is selected depending on the length of the board 2.

[0033] Next, the substrate carry-in process executed by the CPU 27 of the control device 26 when carrying in the substrate 2 will be described. The CPU 27 executes the substrate carry-in process shown in Fig. 5 each time one substrate 2 is carried into the main conveyor 32. Here, the CPU 27 makes the determination in S16 based on the transfer process (first transfer process or second transfer process) stored in the memory 28, and operates the main conveyor 32 in accordance with the selected transfer process (S17, S18). S17 and S18 are performed by executing the subroutines shown in Figs. 6, 7, 10, and 11, respectively.

[0034] First, the first transport process shown in FIGS. 6 and 7 will be described. During transport of the substrate 2, the CPU 27 controls the motor 50 using a speed control pattern including acceleration, constant speed, and deceleration. The motor 50 is controlled by the CPU 27 so that one drive pulse having a predetermined pulse width is output every time a set time T elapses (S21, S22). In S23, the CPU 27 counts up the number of output pulses by incrementing the count value C1 of the first counter 80 by 1 each time the motor 50 outputs one pulse in S21. In S24, the CPU 27 determines whether the count value C1 has reached a set number CA. If the CPU 27 determines that the count value C1 is less than the set number CA (NO in S24), the process proceeds to S25. In S25, the CPU 27 shortens the set time T by ΔT to increase the substrate transport speed. The CPU 27 repeatedly executes S21 to S25 until the count value C1 reaches the set number CA. As shown in FIG. 8, the set number CA is the number of output pulses required for the substrate transport speed to reach the constant travel speed, and is set in advance.

[0035] When the number of output pulses reaches the set number CA (YES in S24), the CPU 27 causes the motor 50 to output one pulse each time the set time T at that time elapses, thereby transporting the substrate 2 at a constant speed (S26, S27). In S29, the CPU 27 determines whether the upstream end of the substrate 2 has been detected by the upstream sensor 60. The CPU 27 determines that the upstream end of the substrate 2 has been detected (YES in S29) when the substrate 2 blocks light from the light-emitting portion 68 of the upstream sensor 60 to the light-receiving portion 70, causing the upstream sensor 60 to output ON (timing t1 in FIG. 8), and then when the substrate 2 passes the upstream sensor 60 and the output of the upstream sensor 60 changes from ON to OFF (timing t2 in FIG. 8), as shown in FIG. 9(a) , the CPU 27 determines that the upstream end of the substrate 2 has been detected (YES in S29). The CPU 27 repeatedly executes S26 to S29 until the upstream end of the substrate 2 is detected. When the upstream end of the substrate 2 is detected, the CPU 27 sets the flag F1 in the memory 28 to 1 in S30. This stores the detection of the upstream end of the substrate 2 by the upstream sensor 60, and in the subsequent processing, since a YES determination is made in S28, S29 to S32 are skipped.

[0036] Furthermore, when the upstream end of the substrate 2 is detected, the CPU 27 calculates in S31 the theoretical number of pulses CT (see FIG. 8 ), which is the drive amount of the motor 50 required to move the substrate from the position where the upstream sensor 60 detects the upstream end of the substrate 2 to the position where the downstream sensor 64 detects the downstream end of the substrate 2. As described above, the length of the substrate 2 and the distance between the sensors are known values. In the first transport process, the length of the substrate 2 is shorter than the distance between the sensors. Therefore, as shown in FIG. 9( a), by subtracting the length of the substrate 2 from the distance between the sensors, the distance (theoretical operation amount) can be calculated from the position where the upstream sensor 60 detects the upstream end of the substrate 2 to the position where the downstream sensor 64 detects the downstream end of the substrate 2. Furthermore, the operation amount of the main conveyor 32 per pulse is known. Therefore, the theoretical number of pulses CT, which is the drive amount of the motor 50 required to operate the main conveyor 32 by the calculated theoretical operation amount, can be calculated. The CPU 27 stores the calculated theoretical number of pulses CT in the memory 28.

[0037] Next, in S32, the CPU 27 calculates, based on the theoretical number of pulses CT, a set number of pulses CS (see FIG. 8 ), which is the drive amount of the motor 50 required to move the board 2 to a predetermined stop position. As shown in FIG. 9C, the stop position is set downstream of the downstream sensor 64 in the transport direction. Here, the set operation amount is a known value. Furthermore, in S31, the theoretical number of pulses CT required to move the main conveyor 32 by the theoretical operation amount is calculated. Therefore, by using the theoretical number of pulses CT, the CPU 27 can calculate the set number of pulses CS, which is the drive amount of the motor 50 required to operate the main conveyor 32 by the set operation amount (i.e., to stop the board 2 at the stop position), based on the ratio between the set operation amount and the theoretical operation amount. The operation of the main conveyor 32 is stopped by gradually decelerating, and the number of pulses CD and deceleration gradient required for deceleration, as shown in FIG. 8, are preset. Therefore, the CPU 27 calculates the set number of pulses CS taking into account the number of pulses CD required for deceleration control.

[0038] In S33, the CPU 27 determines whether the downstream end of the substrate 2 has been detected by the downstream sensor 64. As shown in FIG. 9B, when the substrate 2 blocks light from the light-emitting portion 68 of the downstream sensor 64 to the light-receiving portion 70, causing the output of the downstream sensor 64 to change from OFF to ON (timing t4 in FIG. 8), the CPU 27 determines that the downstream end of the substrate 2 has been detected (YES in S33). The CPU 27 repeatedly executes S26 to S28, S34, and S33 until the downstream end of the substrate 2 is detected. In S34, the CPU 27 counts up the number of output pulses by incrementing the count value C2 of the second counter 82 by 1 each time the motor 50 outputs one pulse. This counts the number of output pulses after the upstream end of the substrate 2 is detected in S29.

[0039] 8 , when the downstream end of the substrate 2 is detected, the CPU 27 detects the actual pulse number CR, which is the driving amount of the motor 50, from the time when the upstream end of the substrate 2 is detected by the upstream sensor 60 (timing t2) to the time when the downstream end of the substrate 2 is detected by the downstream sensor 64 (timing t4). The actual pulse number CR is equal to the count value C2 of the second counter 82.

[0040] Next, in S36 of FIG. 7 , the CPU 27 determines whether the theoretical number of pulses CT and the actual number of pulses CR are equal. When the main conveyor 32 transports the board 2, relative movement occurs between the board 2 and the conveyor belt 36 due to vibrations of the board 2 and the conveyor belt 36, frictional resistance of the guide rails 56 against the board 2, and other factors, which can result in a discrepancy between the theoretical operation amount of the main conveyor 32 and the actual movement amount of the board 2. For example, as shown in FIG. 8 , the actual number of pulses CR obtained when the board 2 is actually moved from the position where the upstream end of the board 2 is detected by the upstream sensor 60 to the position where the downstream end of the board 2 is detected by the downstream sensor 64 may be greater than the theoretical number of pulses CT (the drive amount of the motor 50 from timing t2 to t3). In other words, the actual movement amount of the board 2 per pulse of the motor 50 may be smaller than the theoretical value due to the factors described above. In this case, if the motor 50 is driven by the set number of pulses CS calculated in S32, the board 2 will stop before reaching the stop position. Therefore, when the CPU 27 determines that the theoretical number of pulses CT and the actual number of pulses CR are not equal (NO in S36), in S37, the CPU 27 calculates the corrected set number of pulses CS' by correcting the set number of pulses CS (pre-correction set number of pulses CS) calculated in S32 based on the difference between the actual number of pulses CR and the theoretical number of pulses CT. Specifically, the CPU 27 calculates the corrected set number of pulses CS' by adding the difference (ΔCF) between the actual number of pulses CR and the theoretical number of pulses CT to the pre-correction set number of pulses CS. In the example shown in FIG. 8, ΔCF is a positive value.

[0041] Thereafter, the CPU 27 counts the number of output pulses by incrementing the count value C2 of the second counter 82 by one each time the motor 50 outputs one pulse every time the set time T elapses (S38 to S40), and repeats S38 to S41 until the count value C2 reaches the set number CF+ΔCF (S41). As shown in Fig. 8, the set number CF+ΔCF is the number of output pulses while the substrate transport speed is constant from time t2 onwards.

[0042] When the number of output pulses reaches the set number CF+ΔCF (YES in S41), the CPU 27 thereafter lengthens the set time T by ΔT for each output pulse (S42-S44), gradually reducing the substrate transport speed. In S45, the CPU 27 counts up the number of output pulses by incrementing the count value C2 of the second counter 82 by 1 each time the motor 50 outputs one pulse, and in S46 determines whether the count value C2 has reached the corrected set number of pulses CS'. When the count value C2 has reached the corrected set number of pulses CS' (YES in S46), the CPU 27 clears the count values ​​C1 and C2 to 0, resets the flag F1 to 0, and sets the set time T to its initial value, thereby ending the series of processes.

[0043] On the other hand, if the CPU 27 determines that the theoretical number of pulses CT and the actual number of pulses CR are equal (YES in S36), it executes S48 to S56 without correcting the set number of pulses CS calculated in S32. In the processes of S48 to S56, the set number of pulses CS is not corrected, and the set number of pulses CS differs from the set number of pulses CS' in the processes of S38 to S46, but otherwise S48 to S56 are the same as S38 to S46, respectively.

[0044] Next, the second transfer process shown in Figures 10 and 11 will be described. The second transfer process differs from the first transfer process in the manner in which the substrate 2 is detected by the substrate sensors 60 and 64 and in the manner in which the numbers of pulses CT, CR, and CS are calculated, but the other processes are the same as those of the first transfer process.

[0045] S61 to S68 in FIG. 10 are the same as S21 to S28 in FIG. 6. In S69, the CPU 27 determines whether the downstream end of the substrate 2 has been detected by the upstream sensor 60. As shown in FIG. 13(a), when the substrate 2 blocks light from the light-emitting portion 68 to the light-receiving portion 70 of the upstream sensor 60 and the output of the upstream sensor 60 changes from OFF to ON (timing t11 in FIG. 12), the CPU 27 determines that the downstream end of the substrate 2 has been detected (YES in S69). The CPU 27 repeatedly executes S66 to S69 until the downstream end of the substrate 2 is detected. When the downstream end of the substrate 2 is detected, the CPU 27 sets flag F1 in memory 28 to 1 in S70. This stores the detection of the downstream end of the substrate 2 by the upstream sensor 60, and in subsequent processing, S69 to S72 are skipped because a YES determination is made in S68.

[0046] Furthermore, when the downstream end of the substrate 2 is detected, the CPU 27 calculates in S71 the theoretical number of pulses CT (see FIG. 12 ), which is the drive amount of the motor 50 for moving the substrate 2 from the position where the upstream sensor 60 detected the downstream end of the substrate 2 to the position where the downstream sensor 64 detects the downstream end of the substrate 2. In the second transport process, since the length of the substrate 2 is longer than the distance between the sensors, the distance between the sensors is set as the theoretical operation amount, as shown in FIG. 13( a). Then, the CPU 27 calculates the theoretical number of pulses CT, which is the drive amount of the motor 50 for operating the main conveyor 32 by the set theoretical operation amount.

[0047] Next, in S72, the CPU 27 calculates a set number of pulses CS (see FIG. 12 ), which is the drive amount of the motor 50 for moving the board 2 to a preset stop position, based on the theoretical number of pulses CT. In the second transport process, as in the first transport process, the theoretical number of pulses CT is used to calculate the set number of pulses CS, which is the drive amount of the motor 50 for operating the main conveyor 32 by the set operation amount from the position shown in FIG. 13( a) to the stop position shown in FIG. 13( c).

[0048] In S73, the CPU 27 determines whether the downstream end of the substrate 2 has been detected by the downstream sensor 64. As shown in FIG. 13(b), when the substrate 2 blocks light from the light-emitting portion 68 of the downstream sensor 64 to the light-receiving portion 70 and the output of the downstream sensor 64 changes from OFF to ON (timing t13 in FIG. 13), the CPU 27 determines that the downstream end of the substrate 2 has been detected (YES in S73). The CPU 27 repeatedly executes S66 to S68, S74, and S73 until the downstream end of the substrate 2 is detected. S74 is the same as S34 in FIG. 6.

[0049] 12 , when the downstream end of the substrate 2 is detected by the downstream sensor 64, the CPU 27 detects the actual pulse number CR, which is the driving amount of the motor 50, from the time when the downstream end of the substrate 2 is detected by the upstream sensor 60 (timing t11) to the time when the downstream end of the substrate 2 is detected by the downstream sensor 64 (timing t13). The actual pulse number CR is equal to the count value C2 of the second counter 82.

[0050] Next, in S76 of Fig. 11, the CPU 27 determines whether the theoretical number of pulses CT and the actual number of pulses CR are equal. If the CPU 27 determines that the theoretical number of pulses CT and the actual number of pulses CR are not equal (NO in S76), in S77, similar to S37 of Fig. 7, the CPU 27 calculates a corrected set number of pulses CS' by correcting the set number of pulses CS (pre-correction set number of pulses CS) calculated in S72 based on the difference between the actual number of pulses CR and the theoretical number of pulses CT (see Fig. 12). S78 to S96 are similar to S38 to S56 of Fig. 7, respectively.

[0051] As described above, when the main conveyor 32 transports the board 2, relative movement occurs between the board 2 and the conveyor belt 36 due to vibrations of the board 2 and the conveyor belt 36, frictional resistance of the guide rails 56 relative to the board 2, and inertial forces of the board 2 during acceleration and deceleration. This can cause the actual stop position to deviate from the desired stop position. That is, the movement amount of the board 2 may deviate from the drive amount of the motor 50 (the movement amount of the conveyor belt 36). In the component mounter 10 of this embodiment, the set output power CS of the motor 50 is corrected while the board 2 is being transported based on the difference between the drive amount of the motor 50 and the movement amount of the board 2 calculated based on the detection results of the board sensors 60 and 64. In this way, the component mounter 10 of this embodiment can correct errors in the set output power CS by feeding back this difference while the conveyor 32 is operating, without having to stop the conveyor 32 once. This allows the board to be positioned accurately in a shorter time than with conventional configurations.

[0052] In particular, in this embodiment, two board sensors 60, 64 spaced apart are used to calculate a theoretical number of pulses CT for the board 2 to move the distance from the upstream sensor 60 to the downstream sensor 64, and this distance is compared with the actual number of pulses CR when the board 2 actually moves, thereby making it possible to accurately calculate the deviation in the theoretical output amount CT due to the relative movement between the board 2 and the conveyor 32. Therefore, based on the difference between the theoretical number of pulses CT and the actual number of pulses CR, it is possible to appropriately correct the set number of pulses CS for moving the board 2 to the stop position, and calculate a corrected set number of pulses CS'.

[0053] In this embodiment, different transport processes are performed depending on whether the length of the substrate 2 is longer or shorter than the sensor-to-sensor distance. That is, when the length of the substrate 2 is shorter than the sensor-to-sensor distance, the set number of pulses CS is corrected based on the difference between the theoretical output amount CT and the actual output amount CR when the substrate 2 moves between the upstream sensor 60 and the downstream sensor 64. When the length of the substrate 2 is longer than the sensor-to-sensor distance, the set number of pulses CS is corrected based on the theoretical output amount CT and the actual output amount CR when the substrate 2 moves from the position where the upstream sensor 60 detects the downstream end of the substrate 2 to the position where the downstream sensor 64 detects the downstream end of the substrate 2. By adopting different detection modes depending on the length of the substrate 2, the set number of pulses CS can be appropriately corrected at an earlier stage during transport of the substrate 2. This embodiment allows for accurate correction of deviations that may occur, particularly during constant-speed movement of the substrate 2.

[0054] (Correspondence) The main conveyor 32 is an example of a "substrate transport device." The substrate sensors 60, 64 are an example of a "detection unit." The set pulse number CS is an example of a "set output amount." The positions of the substrate 2 shown in Figures 9(a) and 13(a) and the positions of the substrate 2 shown in Figures 9(b) and 13(b) are examples of a "first position" and a "second position," respectively. The theoretical pulse number CT and the actual pulse number CR are examples of a "theoretical output amount" and a "actual output amount," respectively.

[0055] Example 2 is different from Example 1 in that the mounter 10 does not include the board sensor 64. In Example 2, regardless of the length of the board 2, the third transport process shown in Fig. 14 and Fig. 15 is executed when the board 2 is carried in.

[0056] S101 to S108 in FIG. 10 are the same as S21 to S28 in FIG. 6 . In S109, the CPU 27 determines whether the downstream end of the substrate 2 has been detected by the substrate sensor 60. As shown in FIG. 17A, when the substrate 2 blocks light from the light-emitting portion 68 to the light-receiving portion 70 of the substrate sensor 60 and the output of the substrate sensor 60 changes from OFF to ON (timing t21 in FIG. 16 ), the CPU 27 determines that the downstream end of the substrate 2 has been detected (YES in S109). The CPU 27 repeatedly executes S106 to S109 until the downstream end of the substrate 2 is detected. When the downstream end of the substrate 2 is detected, the CPU 27 sets flag F1 in memory 28 to 1 in S110. This stores the detection of the downstream end of the substrate 2 by the substrate sensor 60, and in the subsequent processing, S109 to S112 are skipped because a YES determination is made in S108.

[0057] Furthermore, when the downstream end of the substrate 2 is detected, the CPU 27 calculates in S111 the theoretical number of pulses CT (see FIG. 16 ), which is the drive amount of the motor 50 required to move the substrate from the position where the substrate sensor 60 detected the downstream end of the substrate 2 to the position where the substrate sensor 60 detected the upstream end of the substrate 2. In the third transport process, since only a single substrate sensor 60 is provided, the distance from the downstream end to the upstream end of the substrate 2 (i.e., the length of the substrate 2) is set as the theoretical operation amount, as shown in FIGS. 17( a) and 17(b). Then, the CPU 27 calculates the theoretical number of pulses CT, which is the drive amount of the motor 50 required to operate the main conveyor 32 by the set theoretical operation amount.

[0058] Next, in S112, the CPU 27 calculates a set number of pulses CS (see FIG. 16 ), which is the drive amount of the motor 50 for moving the board 2 to a preset stop position, based on the theoretical number of pulses CT. In the third transport process, as in the first transport process, the theoretical number of pulses CT is used to calculate the set number of pulses CS, which is the drive amount of the motor 50 for operating the main conveyor 32 by the set operation amount from the position shown in FIG. 17( a) to the stop position shown in FIG. 17( c).

[0059] In S113, the CPU 27 determines whether or not the upstream end of the substrate 2 has been detected by the substrate sensor 60. As shown in FIG. 17(b), when the substrate 2 passes the substrate sensor 60 and the output of the substrate sensor 60 changes from ON to OFF (timing t23 in FIG. 16), the CPU 27 determines that the upstream end of the substrate 2 has been detected (YES in S113). The CPU 27 repeatedly executes S106 to S108, S114, and S113 until the upstream end of the substrate 2 is detected. S114 is the same as S34 in FIG. 6.

[0060] 16 , when the upstream end of the substrate 2 is detected by the substrate sensor 60, the CPU 27 detects the actual pulse number CR, which is the driving amount of the motor 50, from the time when the downstream end of the substrate 2 is detected by the substrate sensor 60 (timing t21) to the time when the upstream end of the substrate 2 is detected by the substrate sensor 60 (timing t23). The actual pulse number CR is equal to the count value C2 of the second counter 82.

[0061] Next, in S116 of Fig. 15, the CPU 27 determines whether the theoretical number of pulses CT and the actual number of pulses CR are equal. If the CPU 27 determines that the theoretical number of pulses CT and the actual number of pulses CR are not equal (NO in S116), in S117, similar to S37 of Fig. 7, the CPU 27 calculates a corrected set number of pulses CS' by correcting the set number of pulses CS (pre-correction set number of pulses CS) calculated in S112 based on the difference between the actual number of pulses CR and the theoretical number of pulses CT (see Fig. 16). S118 to S136 are similar to S38 to S56 of Fig. 7, respectively.

[0062] As explained above, also in the second embodiment, the distance from the downstream end of the substrate 2 until its upstream end passes the substrate sensor 60 is calculated as the theoretical number of pulses CT, and this distance is compared with the actual number of pulses CR when the substrate 2 actually moves, thereby making it possible to accurately calculate the deviation in the theoretical output amount CT caused by the relative movement between the substrate 2 and the conveyor 32. Therefore, based on the difference between the theoretical number of pulses CT and the actual number of pulses CR, the set number of pulses CS for moving the substrate 2 to the stop position can be appropriately corrected, and the corrected set number of pulses CS' can be calculated.

[0063] Furthermore, in this embodiment, the difference between the theoretical output amount CT and the actual output amount CR is calculated using only a single substrate sensor 60. This simplifies the device configuration and reduces costs.

[0064] (Correspondence) The main conveyor 32 is an example of a "board transport device." The board sensor 60 is an example of a "detection unit."

[0065] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above examples are listed below.

[0066] In the above-described embodiments, the set number of pulses CS is corrected when the theoretical number of pulses CT is smaller than the actual number of pulses CR. However, the set number of pulses CS can also be corrected in a similar manner when the theoretical number of pulses CT is larger than the actual number of pulses CR. In this case, the difference between the theoretical number of pulses CT and the actual number of pulses CR is calculated, and the post-correction set number of pulses CS' is calculated by adding a negative value ΔCF to the pre-correction set number of pulses CS based on this difference.

[0067] Furthermore, in the first transport process of Example 1, the length of the substrate 2 does not need to be known. In the first transport process, the length of the substrate 2 may be calculated based on the number of output pulses from when the upstream sensor 60 detects the downstream end of the substrate 2 until when it detects the upstream end.

[0068] Furthermore, in each of the above-described embodiments, the motor 50 is a pulse motor that does not include an encoder, but it may also be, for example, a servo motor that includes an encoder.

[0069] In addition, in each of the above-described embodiments, the upstream end and downstream end of the substrate 2 are detected by the substrate sensors 60, 64. However, for example, the upstream end and downstream end of the substrate 2 may be detected using the reference mark imaging device 22 while the substrate 2 is being transported. In this modified example, the substrate sensors 60, 64 can be omitted.

[0070] The technical elements described in this specification or drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings simultaneously achieve multiple objectives, and achieving one of those objectives is itself technically useful.

Claims

1. A substrate transport device comprising: a conveyor that transports a substrate in a transport direction; a motor that operates the conveyor; a control unit that is capable of executing a transport process in which the conveyor transports the substrate to a predetermined stop position by driving the motor; and at least one detection unit that detects the upstream end and downstream end of the substrate in the transport direction, wherein when executing the transport process, the control unit corrects the set output amount of the motor for moving the substrate to the stop position while the substrate is being transported, based on the difference between the drive amount of the motor and the movement amount of the substrate calculated based on the detection result of the detection unit.

2. The substrate transport device of claim 1, wherein, when performing a transport process, the control unit: calculates, based on the length of the substrate, a theoretical output amount of the motor for the substrate to move a distance between a first position where the detection unit detects the upstream end or the downstream end, and a second position where the detection unit detects the upstream end or the downstream end, the second position being different from the first position; calculates the set output amount based on the theoretical output amount when the detection unit detects the upstream end or the downstream end of the substrate; detects the actual output amount of the motor when the substrate actually moves a distance between the first position and the second position; and corrects the set output amount based on the difference between the theoretical output amount and the actual output amount while the substrate is being transported.

3. The substrate transport device of claim 2, wherein the detection unit comprises an upstream detection unit provided upstream in the transport direction and a downstream detection unit provided downstream of the upstream detection unit, and when the length of the substrate in the transport direction is shorter than the distance between the upstream detection unit and the downstream detection unit, the first position is a position where the upstream detection unit detects the upstream end of the substrate, and the second position is a position where the downstream detection unit detects the downstream end of the substrate, and when performing the transport process, the control unit calculates the set output amount of the motor for moving the substrate from the first position to the stop position based on the theoretical output amount when the upstream detection unit detects the upstream end of the substrate.

4. A substrate transport device as described in claim 3, wherein the control unit calculates the length of the substrate based on the amount of output from the motor between when the upstream detection unit detects the downstream end of the substrate and when it detects the upstream end.

5. The substrate transport device of claim 3, wherein the detection unit comprises an upstream detection unit provided upstream in the transport direction and a downstream detection unit provided downstream of the upstream detection unit, and when the length of the substrate in the transport direction is longer than the distance between the upstream detection unit and the downstream detection unit, the first position is a position where the upstream detection unit detects the downstream end of the substrate, and the second position is a position where the downstream detection unit detects the downstream end of the substrate, and when performing the transport process, the control unit calculates the set output amount of the motor for moving the substrate from the first position to the stop position based on the theoretical output amount when the upstream detection unit detects the downstream end of the substrate.

6. The substrate transport device of claim 2, wherein the substrate transport device is provided with one detection unit that detects the upstream end and the downstream end of the substrate in the transport direction, the first position is a position where the detection unit detects the downstream end of the substrate, the second position is a position where the detection unit detects the upstream end of the substrate, and when performing the transport process, the control unit calculates the set output amount of the motor for moving the substrate from the first position to the stop position based on the theoretical output amount when the detection unit detects the downstream end of the substrate.

7. The substrate transport device according to claim 1, wherein the motor is a motor that does not include an encoder for detecting the rotation angle of the motor.

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