Substrate conveying device

Abstract

Provided is a substrate conveying device capable of more reliably carrying in a substrate from a pre-process device.　The substrate conveying device comprises: a conveyor belt that carries in a substrate from a pre-process device; a drive source that rotates the conveyor belt; and a control device that, until when the front end of the substrate that has been carried out from the pre-process device is transferred to the conveyor belt, controls the drive source to control the rotational speed of the conveyor belt to be less than or equal to the speed at which the pre-process device conveys the substrate, and controls the drive source to accelerate the rotational speed of the conveyor belt according to the timing at which the front end of the substrate that has been carried out from the pre-process device is transferred to the conveyor belt, and thereby causes the substrate to be carried in by the conveyor belt.

Description

Substrate transport device

[0001] The present disclosure relates to a substrate transport apparatus for transporting a substrate.

[0002] Conventionally, each device constituting a manufacturing line for mounting components onto a board is provided with a board transport device for transporting the board. For example, Patent Document 1 listed below describes a board transport device that positions a board in a component mounter at a mounting position where components are mounted. The board transport device transports the board using a conveyor belt.

[0003] Japanese Patent Application Publication No. 10-200299

[0004] The substrate transport device carries in substrates from a pre-processing device, such as a substrate supply device or an intermediate conveyor device connecting devices, and carries out the substrates to a post-processing device. When transporting substrates between the pre-processing device and the substrate transport device, if the conveyor belt transport speeds are different, sufficient friction cannot be obtained between the conveyor belt and the substrate, and the substrate transport device cannot transport the substrate.

[0005] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a substrate transport device that can more reliably transport substrates from a previous process device.

[0006] In order to solve the above problems, this specification discloses a substrate transport device comprising: a conveyor belt that transports substrates from a previous process device; a drive source that rotates the conveyor belt; and a control device that controls the drive source to control the rotational speed of the conveyor belt to be equal to or lower than the speed at which the previous process device transports the substrate until the front end of the substrate transported from the previous process device is transferred onto the conveyor belt, and that controls the drive source to accelerate the rotational speed of the conveyor belt according to the timing at which the front end of the substrate transported from the previous process device is transferred onto the conveyor belt, thereby causing the conveyor belt to transport the substrate.

[0007] According to the substrate transport device of the present disclosure, the rotational speed of the conveyor belt is controlled to be equal to or lower than the transport speed of the upstream process device until the front end of the substrate transported from the upstream process device is transferred onto the conveyor belt. This ensures the frictional force required for the conveyor belt to receive the substrate, allowing the substrate to be transferred more reliably from the upstream process device to the conveyor belt. In other words, the occurrence of substrate transfer errors can be reduced. The substrate transport device then accelerates the rotational speed of the conveyor belt to transport the substrate depending on the timing at which the front end of the substrate transfers onto the conveyor belt. This allows the substrate to be transferred more reliably, and by accelerating the speed after a portion of the substrate has been transferred, the time required to transport the substrate can be shortened.

[0008] 1 is a schematic diagram of a substrate production line 10 of a first embodiment. A schematic diagram of a screen printing machine 12. A block diagram showing the electrical connection relationship of the screen printing machine 12. An explanatory diagram of a printing device 41 and a process transfer device 42. A diagram showing a state in which the process transfer device 42 is raised. A graph showing the relationship between rotation speed V and time in a first acceleration mode. A graph showing the relationship between rotation speed V and time in a second acceleration mode. (a) to (c) are diagrams showing the relationship between a state in which a substrate S is carried into the screen printing machine 12 from the intermediate conveyor 21 and rotation speed V. A graph showing the relationship between rotation speed V and time in a second embodiment. A schematic diagram of a screen printing machine 12A of a third embodiment.

[0009] (Regarding the Board Production Line 10) A board production line according to a first embodiment, which is an embodiment embodying the present disclosure, will be described in detail below with reference to the drawings. FIG. 1 schematically illustrates the board production line 10 according to the first embodiment. As shown in FIG. 1, the board production line 10 according to the first embodiment includes, in order from the upstream side of the production process of the production line, a stocker 11, a screen printing machine 12, a component mounter 13, a reflow machine 14, and an inspection machine 15. The five devices, including the stocker 11, are connected to each other by intermediate conveyors 21 to 25. In FIG. 1, the left side is the upstream side and the right side is the downstream side. The stocker 11, the screen printing machine 12, the component mounter 13, the reflow machine 14, and the inspection machine 15 may be collectively referred to as board transport devices 11 to 15. In the following explanation, the direction of the manufacturing process of the board manufacturing line 10 (to the right in Figure 1) will be referred to as the board transport direction, the up-down direction in Figure 1 will be referred to as the up-down direction, and the direction perpendicular to the board transport direction and the up-down direction (the direction perpendicular to the paper surface of Figure 1) will be referred to as the board width direction.

[0010] The board production line 10 also includes a management PC (abbreviation for computer) 17 (see FIG. 3). The management PC 17 is a device that manages information about each device on the board production line 10. The management PC 17 manages the progress status of each device on the production line. Each of the board transport devices 11 to 15 transmits and receives data to and from the management PC 17, and acquires information about the boards being produced and information about the progress status of other devices.

[0011] The stocker 11 includes a stock device 31 and a process transfer device 32. The stock device 31 temporarily stores substrates on which circuit patterns have been formed, and sequentially supplies the substrates to a supply position 33 below. The process transfer device 32 transfers the substrates from the supply position 33 of the stock device 31 to a downstream discharge port 35 in the stocker 11. The screen printing machine 12 includes a printing device 41 and a process transfer device 42. The printing device 41 applies a viscous fluid to the substrates. The process transfer device 42 transfers the substrates from an upstream discharge port 43 in the screen printing machine 12, via a printing position 44 below the printing device 41, to a downstream discharge port 45.

[0012] The component mounter 13 includes a component mounting device 51 and a process transfer device 52. The component mounting device 51 mounts electronic components on a board carried in from the screen printing machine 12. The process transfer device 52 transfers the board from an upstream carry-in entrance 53 of the component mounter 13, through a mounting position 54 below the component mounting device 51, to a downstream carry-out exit 55. The reflow machine 14 includes a reflow device 61 and a process transfer device 62. The reflow device 61 fixes the viscous fluid applied by the screen printing machine 12. The process transfer device 62 transfers the board from an upstream carry-in entrance 63 of the reflow machine 14, through a reflow position 64 below the reflow device 61, to a downstream carry-out exit 65. The inspection machine 15 includes an inspection device 71 and a process transfer device 72. The inspection device 71 inspects the mounting state of electronic components mounted on the board. The process transfer device 72 transfers the substrate from an upstream entrance 73 in the inspection machine 15 , through an inspection position 74 below the inspection device 71 , to a downstream exit 75 .

[0013] The process transfer devices 32, 42, 52, 62, and 72 provided in the substrate transfer devices 11-15, respectively, are capable of changing the substrate transfer speed at which they transfer substrates. The substrate transfer devices 11-15 change the substrate transfer speeds of the process transfer devices 32, 42, 52, 62, and 72, for example, based on detection signals S1-S3 from substrate sensors (such as the substrate sensors 121-123 in FIG. 2 ), which will be described later. Furthermore, the substrate transfer devices 11-15 execute substrate transfer based on commands from a management PC 17 that manages the substrate manufacturing line 10. Meanwhile, the intermediate conveyors 21-25 each transport substrates at a preset substrate transfer speed, and transport substrates at a constant substrate transfer speed. The intermediate conveyors 21-24 are arranged between the substrate transfer devices 11-15, in this order, and the intermediate conveyor 25 is arranged downstream of the substrate transfer device 15. Each of the intermediate conveyors 21 to 25 switches between a state in which the board is conveyed at a constant board conveying speed and a state in which the board conveying is stopped based on instructions in control information C2 (see FIG. 2) described below. Note that the intermediate conveyors 21 to 25 may be configured to be able to change the board conveying speed.

[0014] (Regarding the Screen Printer 12) In the following explanation, of the substrate transport devices 11 to 15, the screen printer 12 will be explained. However, the control of the screen printer 12 described below can be similarly performed on the other substrate transport devices 11, 13 to 15. Figure 2 shows a schematic configuration of the screen printer 12, as viewed from the substrate width direction. Figure 3 shows the electrical connection relationship of the screen printer 12. Figure 4 shows a schematic configuration of the printing device 41 and the process transfer device 42, as viewed from the substrate transport direction.

[0015] As shown in FIGS. 2 to 4 , the screen printing machine 12 includes the printing device 41 and the process transport device 42, as well as a main body 47, a control device 48 (see FIG. 3 ), and an external IF (abbreviation of interface) 49 (see FIG. 3 ). The control device 48 is configured as a microprocessor centered on a CPU 48A and controls the entire screen printing machine 12. The screen printing machine 12 executes printing operations under the control of the control device 48. Specifically, the screen printing machine 12 uses a squeegee 80 of the printing device 41 to push a viscous fluid on a screen mask M into pattern holes 77 formed in the screen mask M, thereby applying (printing) the viscous fluid through the pattern holes 77 onto a substrate S serving as a printing target below. Examples of the "printing target" include a substrate S on which components are mounted and a three-dimensional object. Examples of the "viscous fluid" include solder paste, conductive paste, adhesive, and the like. The following description will be given using a substrate S as an example of the printing target and solder paste as an example of the viscous fluid. The screen printing machine 12 is also connected to a management PC 17 and intermediate conveyors 21 and 22 via an external IF 49 .

[0016] The main body 47 includes a cover for the screen printing machine 12 and is equipped with the aforementioned inlet 43 and outlet 45. The printing device 41 is located in the upper portion of the main body 47 and is a unit that prints solder paste on a substrate S using a screen mask M. The printing device 41 includes a print head 81, a print movement unit 82 ( FIG. 3 ), a squeegee lifting / lowering unit 83 ( FIG. 3 ), a supply unit 85, and a mask unit 87. The print movement unit 82 moves the print head 81 in a predetermined printing direction and includes a guide formed along the movement direction, a slider that moves along the guide, and a motor that drives the slider. The print head 81 of this embodiment is configured to have, for example, two detachable squeegees 80. The squeegee lifting / lowering unit 83 is configured to individually raise and lower the two squeegees 80 attached to the print head 81.

[0017] The supply unit 85 can be switched between a state in which it is connected to the print head 81 and a state in which it is disconnected. In the connected state, the supply unit 85 moves together with the print head 81 when the print head 81 is moved by the print moving unit 82. The supply unit 85 includes a container for storing solder paste and a drive mechanism for discharging the solder paste from the container, and discharges the solder paste onto the screen mask M based on the control of the control device 48. By disconnecting the supply unit 85 from the print head 81, it can wait at an exchange position where the container is exchanged. This allows printing by the print head 81 to be performed while the container is being exchanged. The supply unit 85 may also be configured to be constantly connected to the print head 81.

[0018] The mask unit 87 is provided between the print head 81 and the process transfer device 42 in the vertical direction, and is a unit that fixes and holds the screen mask M. The mask unit 87 positions the screen mask M and fixes it in a horizontal position.

[0019] The process transfer device 42 is provided below the mask unit 87 and is a device that carries in the substrate S, positions the carried-in substrate S at the printing position 44, and performs the operations of bringing the substrate S into contact with the screen mask M and separating the substrate S from the screen mask M. The process transfer device 42 includes a pair of side frames 91, a pair of substrate transport conveyors 92, a pair of substrate guides 93, a substrate guide moving unit 94 (see FIG. 3), a side frame moving unit 95 (see FIG. 3), a fixing unit lifting / lowering unit 96, a support table lifting / lowering unit 97, a support table 98, and a substrate support member 99.

[0020] Each of the pair of substrate transport conveyors 92 includes a conveyor belt 101 (see FIG. 2), a plurality of rollers 102 (see FIG. 2), and a servo motor 103. The rollers 102 are rotatably attached to, for example, the inner wall of the side frame 91. The conveyor belt 101 is an endless, circular belt that is stretched over the rollers 102 and rotates from the inlet 43 to the outlet 45. The servo motor 103 is a drive source that rotates the conveyor belt 101. For example, the output shaft of the servo motor 103 is connected to any of the rollers 102 via a reduction gear or the like. The process transfer device 42 controls the rotational operation of the servo motor 103 based on the control of the control device 48, and changes the rotational speed of the rollers 102, thereby changing the rotational speed V of the conveyor belt 101. This changes the substrate transport speed of the substrate S transported by the conveyor belt 101. The conveyor belt 101 rotates (rotates) in the clockwise direction in FIG. 2, thereby transporting the placed substrate S in the substrate transport direction, that is, to the right in FIG.

[0021] The servo motor 103 is an example of a drive source in the present disclosure. Note that the drive source in the present disclosure is not limited to a servo motor, and may be another drive source capable of rotating the conveyor belt 101, such as a stepping motor. Similarly, the drive sources of other conveyor belts (such as a conveyor belt 131 of the intermediate conveyor 21, which will be described later) other than the conveyor belt 101 may also be changed as appropriate. In this embodiment, a case where a servo motor is used as the drive source will be described.

[0022] The board guides 93 are plate-shaped members attached to the upper surfaces of the pair of side frames 91. The pair of side frames 91 are disposed on plate-shaped fixed portions 105 and are plate-shaped members elongated in the board transport direction. The pair of side frames 91 are slidable in the board width direction relative to the fixed portions 105. The side frame moving portion 95 is a mechanism that moves the pair of side frames 91 in the board width direction to move them closer to each other or move them apart. This allows the pair of side frames 91 to move in the board width direction, adjusting the spacing between the pair of side frames 91 in accordance with the width dimension of the board S. The pair of board guides 93 move in the board width direction together with the side frames 91. The pair of board guides 93 are slidable in the board width direction relative to the pair of side frames 91. The board guide moving portion 94 is a mechanism that moves the pair of board guides 93 in the board width direction to move them closer to each other or move them apart. As a result, the pair of board guides 93 move in the board width direction, sandwiching and fixing the board S from both sides in the board width direction with the upper surface of the board S being flush with the upper surfaces of the board guides 93. The fixing part lifting / lowering part 96 is a mechanism that raises and lowers the fixing part 105 relative to the main body part 47. Therefore, the board S placed on the board transport conveyor 92 rises and falls together with the side frames 91 by driving the fixing part lifting / lowering part 96.

[0023] The support table 98 is disposed between the pair of side frames 91 above the fixed portion 105 and is supported from below by the support table lifting portion 97. The support table lifting portion 97 is a mechanism for raising and lowering the support table 98 relative to the fixed portion 105. The support table 98 is a member on which a substrate support member 99 can be placed. Therefore, by driving the support table lifting portion 97, the substrate support member 99 rises and falls together with the support table 98. As shown in FIG. 5 , the control device 48 controls the fixed portion lifting portion 96 to raise the substrate S and drives the support table lifting portion 97 to raise the support table 98. The substrate support member 99 is connected to a pressure reducing device (not shown) via piping and supports the substrate S from the underside while adsorbing and fixing the substrate S by negative pressure. The substrate S is supported from below by the substrate support member 99, and solder paste is applied to the substrate S while it is in contact with the screen mask M (pattern holes 77) from below.

[0024] When carrying in and out the substrate S, the control device 48 drives the fixing unit lifting / lowering unit 96 and the support platform lifting / lowering unit 97 to place the fixing unit 105 and the support platform 98 in the lowered position shown in Fig. 4. After carrying in the substrate S, the control device 48 drives the fixing unit lifting / lowering unit 96 and the support platform lifting / lowering unit 97 to place the fixing unit 105 and the support platform 98 in the raised position shown in Fig. 5. In the following description, the position of the fixing unit 105 and the support platform 98 shown in Fig. 4 will be referred to as the transport position, and the position of the fixing unit 105 and the support platform 98 shown in Fig. 5 will be referred to as the print execution position.

[0025] The screen printing machine 12 also includes a cleaning unit 111 and an imaging unit 112. The cleaning unit 111 is a unit that cleans the back surface of the screen mask M with a cleaning member. The imaging unit 112 is, for example, a camera that captures images of the substrate S and the screen mask M. The control device 48 performs operations such as aligning the screen mask M and the substrate S based on the image data captured by the imaging unit 112.

[0026] 2, the screen printing machine 12 is equipped with three substrate sensors 121, 122, and 123. The three substrate sensors 121 to 123 are used to detect the substrate being transported and are, for example, non-contact sensors such as infrared sensors. The detection method of the substrate sensors 121 to 123 is not particularly limited, and a method using visible light or the like may also be used. Furthermore, the substrate sensors 121 to 123 are not limited to non-contact sensors, and may also be contact sensors using relays or the like.

[0027] The above-described configuration of the screen printing machine 12 is merely an example. For example, the substrate support member 99 may be replaceable depending on the type of substrate S. The pair of side frames 91 may be fixed in position. In this case, the process transfer device 42 may not include the side frame moving unit 95. The process transfer device 42 may not include the fixed unit lifting unit 96. That is, the process transfer device 42 may not include a device for lifting the substrate transport conveyor 92. In this case, the transport position for transporting the substrate S and the printing position for printing may be at the same position (height). The screen printing machine 12 may also be configured to be able to lower the print head 81 and the mask unit 87 to the position of the substrate S. The process transfer device 42 may not include the cleaning unit 111. The process transfer device 42 may not include the imaging unit 112. Furthermore, the process transfer device 42 may not be provided with the substrate sensors 121, 122, and 123 that detect the position of the substrate S, etc.

[0028] (Regarding the substrate sensors 121-123) The process transfer device 42, when placed at the transfer position, is a device that transfers the substrate S from the inlet 43 to the outlet 45 via the printing position 44. At the transfer position, as shown in FIG. 2, the upstream end (left end in FIG. 2) of the conveyor belt 101 is at the same height as the inlet 43, and the downstream end is at the same height as the outlet 45. The upstream end of the conveyor belt 101 is the upstream folded-back portion of the circular conveyor belt 101 (upstream end 147 in FIG. 8), as shown in FIG. 8 (described later). Similarly, the downstream end is the downstream folded-back portion. The substrate sensors 121-123 output detection signals S1-S3 corresponding to whether or not the substrate S is present in the detection area of ​​each sensor for the substrate S being transferred by the process transfer device 42 placed at the transfer position.

[0029] The board sensor 121 is provided near the carry-in entrance 43, and a detection area for detecting the board S is set at a position upstream of the upstream end of the conveyor belt 101 in the board transport direction. The detection area of ​​the board sensor 121 is set, for example, between the conveyor belt 101 of the screen printing machine 12 and the conveyor belt 131 of the upstream intermediate conveyor 21 in the board transport direction. For example, the board sensor 121 outputs a low-level detection signal S1 to the control device 48 when the board S is not present in the detection area, and outputs a high-level detection signal S1 to the control device 48 when the board S is present in the detection area. Note that the other board sensors 122 and 123 similarly output detection signals S2 and S3, respectively. The control device 48 can detect that the front end SF of the board S is approaching the carry-in entrance 43 or the conveyor belt 101 based on the detection signal S1 of the board sensor 121 rising from low to high (hereinafter sometimes referred to as turning on). Furthermore, the control device 48 can detect that the rear end SR of the substrate S has passed through the detection area of ​​the substrate sensor 121, i.e., that the substrate S has been completely transported into the screen printing machine 12, based on the detection signal S1 turning on and then falling from high to low (hereinafter, this may be referred to as turning off).

[0030] The substrate sensor 122 is provided upstream of the position of the discharge port 45. The detection area of ​​the substrate sensor 122 is set at a position close to the discharge port 45 within the screen printing machine 12. The control device 48 can detect that the front end SF of the substrate S has reached a predetermined position within the screen printing machine 12 based on the detection signal S2 of the substrate sensor 122 being turned on. The control device 48 detects that the substrate S has arrived at the printing position 44 based on the detection signal S2 being turned on.

[0031] The substrate sensor 123 is provided near the discharge port 45. The detection area of ​​the substrate sensor 123 is set, for example, between the conveyor belt 101 and the conveyor belt 132 of the downstream intermediate conveyor 22. The control device 48 detects the passage of the rear end portion SR of the substrate S, i.e., the completion of discharge of the substrate S, based on the detection signal S3 of the substrate sensor 123 being turned off.

[0032] The control device 48 outputs a control command D1 to the servo motor 103 based on the detection signals S1 to S3 of the three board sensors 121 to 123, thereby controlling the rotational speed V. Specifically, for example, the servo motor 103 is provided with a motor drive circuit (servo amplifier) ​​that controls the current supplied to the motor. The control device 48 controls the current supplied from the motor drive circuit to the motor (windings, etc.) of the servo motor 103 by changing the control command D1 output to the motor drive circuit of the servo motor 103. The control command D1 includes the target rotational speed, acceleration, rotation direction, target torque, etc. of the motor. The motor drive circuit feedback-controls the servo motor 103 based on the control command D1 input from the control device 48 and encoder information (rotational position information, etc.) input from an encoder provided in the servo motor 103, thereby controlling the servo motor 103 to the target rotational speed, etc. As a result, the control device 48 can control the servo motor 103 at a predetermined rotational speed and acceleration, and thereby control the rotational speed V.

[0033] (Regarding the intermediate conveyors 21, 22) The upstream intermediate conveyor 21 is equipped with, in addition to the endless circular conveyor belt 131 described above, a servo motor 135 that rotates the conveyor belt 131 and a carry-in control device 136 that controls the servo motor 135. Similarly, the downstream intermediate conveyor 22 is equipped with, in addition to the endless circular conveyor belt 132 described above, a servo motor 137 that rotates the conveyor belt 132 and a control device 138 that controls the servo motor 137. In the following explanation, to avoid complexity, the conveyor belt 131 and servo motor 135 of the intermediate conveyor 21, which is on the carry-in side (upstream side) as viewed from the screen printing machine 12, will be referred to as the carry-in belt 131 and the carry-in motor 135, and the conveyor belt 132 and servo motor 137 of the intermediate conveyor 22, which is on the carry-out side (downstream side), will be referred to as the carry-in belt 131 and the carry-in motor 135, respectively, and the conveyor belt 132 and servo motor 137 of the intermediate conveyor 22, which is on the carry-out side (downstream side), will be referred to as the carry-out belt 132 and the carry-out motor 137, respectively, to avoid complexity.

[0034] The carry-in belt 131 is disposed with a predetermined gap between its downstream end 143 (see FIG. 8A) and the upstream end 147 (see FIG. 8A) of the conveyor belt 101 of the screen printing machine 12. The detection area of ​​the substrate sensor 121 is set as an area in which the front end SF disposed in this gap can be detected. The intermediate conveyor 21 is set so that the rotation speed of the carry-in motor 135 is constant, causing the carry-in belt 131 to rotate at a constant rotation speed (rotary speed). The rotation speed of the carry-in belt 131 is referred to as the carry-in rotation speed VI. The carry-in rotation speed VI can also be referred to as the substrate transport speed at which the intermediate conveyor 21 transports the substrate S. The control device 48 of the screen printing machine 12 transmits and receives control information C2 to and from the carry-in control device 136 via the external IF 49. The carry-in control device 136 outputs a control command D2 to the carry-in motor 135 to control it. The loading control device 136 controls the loading motor 135 based on the control information C2, switching between a state in which the loading belt 131 rotates at the loading rotation speed VI to transport the substrate S at a constant speed, and a state in which the rotation of the loading belt 131 is stopped to stop the transport.

[0035] The configurations of the intermediate conveyor 22 and the board sensor 123 are similar to those of the intermediate conveyor 21 and the board sensor 121. Therefore, detailed descriptions of the intermediate conveyor 22 and the board sensor 123 will be omitted. The discharge control device 138 of the intermediate conveyor 22 outputs a control command D3 to the discharge motor 137 to control the discharge motor 137. The discharge control device 138 controls the discharge motor 137 based on control information C3 from the control device 48 to switch between a state in which the discharge belt 132 rotates at the discharge rotational speed VO to transport the board S at a constant speed, and a state in which the rotation of the discharge belt 132 is stopped to stop transport. Note that instructions (control information C2, C3) to start and stop the rotation of the intermediate conveyors 21, 22 may be executed by a device other than the screen printing machine 12. For example, the management PC 17 may instruct the intermediate conveyors 21, 22 to start and stop rotation.

[0036] (Regarding Control of Rotational Speed ​​V) Here, in the substrate production line 10, when the substrate S is transported from an arbitrary conveyor belt in a previous process to a conveyor belt in a subsequent process, if a difference occurs in the rotational speed of the conveyor belts, the substrate S may not be able to transfer. For example, when the substrate S is carried into the screen printing machine 12 from the intermediate conveyor 21, if the rotational speed V (e.g., 200 mm / s) of the conveyor belt 101 is faster than the carry-in rotational speed VI (e.g., 100 mm / s) of the intermediate conveyor 21, there is a risk that a sufficient frictional force may not be ensured between the conveyor belt 101 and the substrate S. As a result, a situation occurs in which the substrate S cannot be transferred from the carry-in belt 131 to the conveyor belt 101.

[0037] In contrast, the screen printing machine 12 of this embodiment has a first acceleration mode shown in FIG. 6 and a second acceleration mode shown in FIG. 7 as modes for carrying in the substrate S. The control device 48 can more reliably transfer the substrate S by changing the rotational speed V in accordance with each acceleration mode. First, the first acceleration mode will be described. FIG. 6 shows changes in the rotational speed V in the first acceleration mode, with the horizontal axis representing time and the vertical axis representing the rotational speed V. As shown in FIG. 6, the first acceleration mode is a mode in which the rotational speed V is switched from a first rotational speed V1 to a second rotational speed V2 at timing TM2 after a predetermined time T has elapsed since timing TM1.

[0038] 8 shows the relationship between the state of the substrate S being carried into the screen printing machine 12 from the intermediate conveyor 21 and the rotation speed V. As described above, each of the substrate transport devices 11-15 transmits and receives data to and from the management PC 17 to acquire information on the progress of other devices. For example, the control device 48 of the screen printing machine 12 instructs the intermediate conveyor 21 to start rotation using control information C2 in accordance with the timing at which the substrate S is carried out from the stocker 11. Based on the input of the control information C2, the intermediate conveyor 21 rotates the carry-in belt 131 at a constant carry-in rotation speed VI. The carry-in rotation speed VI is, for example, 100 mm / s.

[0039] As shown in FIG. 8A , the board S is guided by the board guides 141 of the intermediate conveyor 21 and transported in the board transport direction by the carry-in belt 131 at a carry-in rotational speed VI. In the state shown in FIG. 8A , the front end SF of the board S is upstream of the downstream end 143 of the carry-in belt 131 and has not yet reached the detection area 145 of the board sensor 121. The front end SF is the downstream end of the board S in the board transport direction (the leading end in the board transport direction). The detection signal S1 of the board sensor 121 is in an OFF state at a low level. In other words, the detection area 145 of the board sensor 121 is set to a position downstream of the downstream end 143 of the carry-in belt 131. In the state shown in FIG. 8A , the control device 48 rotates the conveyor belt 101 at a first rotational speed V1. The first rotational speed V1 is, for example, 50 mm / s. Therefore, in the state shown in Figure 8 (a), the control device 48 rotates the conveyor belt 101 at a first rotational speed V1 (50 mm / s) which is slower than the loading rotational speed VI (100 mm / s) of the intermediate conveyor 21, which is the previous process device.

[0040] Next, as shown in FIG. 8B , the substrate S is transported by the transport belt 131 at the transport rotation speed VI, and the front end SF of the substrate S is transported to a position downstream of the downstream end 143. The front end SF reaches (enters) the detection area 145 of the substrate sensor 121. The detection area 145 is, for example, an area that blocks the optical axis of the optical sensor. When the front end SF reaches the detection area 145, the detection signal S1 changes from an OFF state to an ON state at a high level. The control device 48 starts timing the predetermined time T at the timing when the detection signal S1 turns ON. Therefore, timing TM1 in FIG. 6 is the timing when the front end SF reaches the detection area 145 of the substrate sensor 121. In other words, it is the timing when the substrate sensor 121 detects the front end SF of the substrate S transported from upstream. Even in the state shown in FIG. 8B, the control device 48 rotates the conveyor belt 101 at the first rotation speed V1 (50 mm / s).

[0041] Next, as shown in FIG. 8( c), the substrate S is further transported by the carry-in belt 131 and protrudes further in the substrate transport direction from the downstream end 143 of the carry-in belt 131. The front end SF is, for example, downstream of the upstream end 147 in the substrate transport direction and reaches a position where it contacts the conveyor belt 101. When the substrate S contacts the upper surface of the conveyor belt 101, a force (transport force) in the substrate transport direction is applied from the conveyor belt 101 due to friction between the substrate S and the conveyor belt 101. This state shown in FIG. 8( c) corresponds to timing TM2 in FIG. 6. When the first acceleration mode is set, the control device 48 executes a control command D1 to the servo motor 103 at timing TM2, which is a predetermined time T after timing TM1, to switch the rotational speed V of the conveyor belt 101 from the first rotational speed V1 to the second rotational speed V2. Specifically, the control device 48 executes, for example, a control command D1 to change the target rotation speed from a first rotation speed V1 to a second rotation speed V2 to a motor drive circuit (servo amplifier) ​​of the servo motor 103. The second rotation speed V2 is, for example, 200 mm / s.

[0042] Therefore, the control device 48 of this embodiment accelerates the rotation speed V in accordance with the timing at which the front end SF of the substrate S is transferred onto the conveyor belt 101, based on the detection by the substrate sensor 121 of the substrate S carried out from the intermediate conveyor 21, which is a previous-process device. As described above, if the conveyor belt 101 of the subsequent process is rotated faster than the carry-in belt 131 of the previous process when no substrate S has been transferred onto it, the frictional force required for the transfer cannot be sufficiently secured, and the conveyor belt 101 will slip relative to the substrate S. No matter how much the carry-in belt 131 is rotated, the conveyor belt 101 will not be able to retract. In contrast, in this embodiment, acceleration is started when the front end SF, i.e., a part of the substrate S, is placed on the conveyor belt 101 of the subsequent process. This allows the acceleration of the conveyor belt 101 to be started in a state in which the frictional force required for the transfer is reliably generated between the conveyor belt 101 and the substrate S. Even if a difference in rotation speed occurs between the pre-processing equipment and the post-processing equipment, the occurrence of transfer errors of the substrate S can be suppressed, and the substrate S can be stably carried into the post-processing equipment.

[0043] Reasons for this difference in the rotational speed V of the conveyor belt 101 include, for example, the fact that the various devices (board transport devices 11-15 and intermediate conveyors 21-25) in the board production line 10 are manufactured by different manufacturers, and the lack of clearly defined transport speed standards (standard speeds) within the industry. For this reason, users may select an inexpensive intermediate conveyor 21, etc., based on the price of the device and the manufacturing cost of the board S. As a result, for example, slower intermediate conveyors 21-25 are placed between the screen printing machine 12 and component mounter 13, which have higher transport speeds, resulting in differences in transport speed (rotational speed) between the devices. Furthermore, some devices cannot change their transport speed, which can lead to problems such as unresolved speed differences and incorrect transfer of the board S. On the other hand, from the perspective of shortening cycle time and reducing manufacturing costs, a faster transport speed for the board S is preferable. Therefore, in the screen printing machine 12 of this embodiment, by accelerating the substrate S after a portion of the substrate S has been transferred, it is possible to reduce the cycle time and manufacturing costs while suppressing transfer errors of the substrate S.

[0044] Although the above description has been made with respect to the screen printing machine 12, similar speed control can be performed for the other substrate transport devices 13-15 (process transfer devices 52, 62, 72), thereby reducing cycle time and manufacturing costs while suppressing transfer errors of the substrate S. Furthermore, similar speed control can be performed for the most upstream stocker 11 when receiving substrates S from a previous process device further upstream (such as a substrate S supply robot or an AGV (automated guided vehicle)). Naturally, similar speed control can also be performed for the intermediate conveyors 21-25 when transporting substrates S from a previous process device. Therefore, if any of the devices (substrate transport devices 11-15, intermediate conveyors 21-25) arranged on the substrate production line 10 operates at a low speed, the present disclosure can be applied to the device following that device.

[0045] As shown in FIG. 4 , the process transfer device 42 of this embodiment is configured to transport only both ends of the substrate S in the substrate width direction by the conveyor belt 101. For example, the width of contact between one end of the substrate S and the conveyor belt 101 in the substrate width direction is several millimeters. This configuration is more likely to result in insufficient frictional force than a configuration in which the conveyor belt 101 is provided over the entire underside of the substrate S, bringing the entire underside into contact with the conveyor belt 101. In particular, if the substrate S is warped due to expansion or contraction of the insulating resin, the contact area between the one end of the substrate S and the conveyor belt 101 may become even smaller. On the other hand, if a device such as the support table 98 or the support table lifting unit 97 shown in FIG. 4 , i.e., a device that brings the substrate S into contact with the screen mask M, is to be provided below the substrate S at the printing position 44, it is necessary to ensure sufficient operating space below the substrate S. Therefore, it is difficult to provide the conveyor belt 101 over the entire underside of the substrate S. For this reason, in a configuration in which the conveyor belt 101 contacts only the edges of the substrate in the width direction while conveying it, as in the screen printing machine 12 of this embodiment, it is extremely effective to perform the speed control described above.

[0046] As shown in FIG. 8A , the substrate sensor 121 of this embodiment has a detection area 145 located upstream of the upstream end 147 of the conveyor belt 101 in the substrate conveyance direction. The predetermined time T is set to the time required from the timing TM1 at which the substrate S is detected by the substrate sensor 121 until the front end SF of the substrate S starts to transfer onto the conveyor belt 101. The contact of the front end SF, which has been conveyed from upstream, with the conveyor belt 101 and then transfers onto it may be referred to as "transferring" or "starting to transfer." This allows the predetermined time T to be set, for example, as the distance between the position of the front end SF when the detection signal S1 shown in FIG. 8B turns on and the position at which the front end SF contacts the conveyor belt 101 shown in FIG. 8C divided by the loading rotation speed VI. An appropriate predetermined time T can be set based on the arrangement of the substrate sensor 121 and the loading rotation speed VI, and acceleration can begin at the timing at which the substrate S starts to transfer onto the conveyor belt 101. This reduces the loading time.

[0047] Furthermore, the control device 48 executes a control command D1 to the servo motor 103 to switch from the first rotation speed V1 to the second rotation speed V2 in response to the lapse of a predetermined time T. The second rotation speed V2 is set to a speed faster than the loading rotation speed VI. This makes it possible to reduce the loading time and the cycle time while suppressing transfer errors of the substrate S.

[0048] Furthermore, the first rotational speed V1 in this embodiment is slower than the carry-in rotational speed VI of the intermediate conveyor 21, which is the upstream process device. As a result, before and at the time of transfer of the substrate S, by starting the transfer at the first rotational speed V1 slower than that of the upstream process device, it is possible to prevent the conveyor belt 101 from slipping relative to the substrate S, and to more reliably start the transfer of the substrate S. By starting the transfer at a relatively slow rotational speed V, it is possible to prevent, as much as possible, the rotation of the conveyor belt 101 from interfering with the propulsive force of the intermediate conveyor 21 that attempts to carry the substrate S out. Furthermore, by starting acceleration from the moment the transfer begins, the substrate S can be quickly carried in (transferred).

[0049] The above-described values ​​of the loading rotation speed VI, the first rotation speed V1, and the second rotation speed V2 are merely examples. For example, the first rotation speed V1 may be the same as the loading rotation speed VI. That is, after the predetermined time T has elapsed, the upstream process device and the downstream process device may be rotating at the same rotation speed. Therefore, the first rotation speed V1 may be set to a rotation speed equal to or lower than the loading rotation speed VI. Furthermore, the second rotation speed V2 may be set to a speed higher than the first rotation speed V1.

[0050] Next, the second acceleration mode will be described. As shown in Fig. 7 , the second acceleration mode is a mode in which acceleration is performed at a constant acceleration rate from the first rotational speed V1 to the second rotational speed V2 at a timing TM2 after a predetermined time T has elapsed from the timing TM1. In the first acceleration mode, the control device 48 executes a control command D1 for the servo motor 103 to switch the rotational speed V from the first rotational speed V1 to the second rotational speed V2. In contrast, in the second acceleration mode, the control device 48 executes a control command D1 for gradually accelerating the servo motor 103 from the first rotational speed V1 to the second rotational speed V2 at a predetermined acceleration rate.

[0051] When the second acceleration mode is set, the control device 48 executes the control shown in FIGS. 8A and 8B , as in the first acceleration mode. Then, as shown in FIG. 8C , the control device 48 starts accelerating the rotational speed V when a predetermined time T has elapsed, i.e., when the front end SF reaches (contacts) the conveyor belt 101. Therefore, the control device 48 executes a control command D1 to the servo motor 103 to accelerate the rotational speed V from the first rotational speed V1 to the second rotational speed V2 at a constant acceleration, in response to the elapse of the predetermined time T from the time TM1 when the substrate S is detected by the substrate sensor 121. Even in this second acceleration mode, it is possible to reduce the cycle time while suppressing the occurrence of transfer errors of the substrate S. Furthermore, gradual acceleration more reliably prevents the substrate S from slipping on the conveyor belt 101.

[0052] The first acceleration mode also requires acceleration to increase the rotational speed V. Therefore, the difference between the first acceleration mode and the second acceleration mode can be said to be the magnitude of acceleration. For example, the first acceleration mode is a mode in which the servo motor 103 accelerates from the first rotational speed V1 to the second rotational speed V2 at the maximum acceleration based on the control command D1. In contrast, the second acceleration mode is a mode in which the servo motor 103 accelerates at an acceleration value specified by the control command D1 from the control device 48. In other words, the first acceleration mode can be said to be a mode in which the acceleration is greater than that of the second acceleration mode. Note that the above definitions of each acceleration mode are merely examples. For example, the second acceleration mode may be a mode in which the acceleration is reduced by a predetermined value from the acceleration of the first acceleration mode. In other words, the acceleration of each acceleration mode may be defined relatively. In this case, in the second acceleration mode, the control device 48 does not need to specify the acceleration value by the control command D1.

[0053] Here, depending on the characteristics of the substrate S, the second acceleration mode may be more suitable than the first acceleration mode. For example, if the substrate S is light, performing a sudden acceleration such as in the first acceleration mode when the front end SF begins to transfer to the conveyor belt 101 may cause the substrate S to slip on the conveyor belt 101. For this reason, if the substrate S is light, a gradual acceleration mode such as the second acceleration mode is more suitable. Conversely, if the substrate S is heavy, the frictional force between the substrate S and the conveyor belt 101 increases, so applying the first acceleration mode can shorten the cycle time compared to the second acceleration mode. Therefore, it is preferable to apply the first acceleration mode when the weight of the substrate S is equal to or greater than a predetermined weight, and the second acceleration mode when the weight is less than the predetermined weight.

[0054] Furthermore, when the length of the substrate S in the substrate conveyance direction is long, i.e., when the substrate S is long in the direction in which the conveyor belt 101 extends, the size of the portion of the substrate S remaining on the carry-in belt 131 side when the front end SF begins to transfer to the conveyor belt 101 is larger than when the length in the substrate conveyance direction is short. When the remaining portion is large, the frictional force generated between the carry-in belt 131 and the substrate S increases, and even when the conveyor belt 101 tries to pull the substrate S, the force tending to remain on the carry-in belt 131 side increases. Therefore, when a long substrate S is subjected to rapid acceleration such as in the first acceleration mode, the force tending to remain on the carry-in belt 131 side may cause the substrate S to slip relative to the conveyor belt 101. Therefore, when the substrate S is long, a gradual acceleration mode such as the second acceleration mode is suitable. Conversely, when the substrate S is short, the force tending to remain on the carry-in belt 131 is smaller, so by applying the first acceleration mode, it is possible to shorten the cycle time, etc., compared to the second acceleration mode. Therefore, it is preferable to apply the first acceleration mode when the length of the substrate S in the substrate transport direction is equal to or shorter than a predetermined length, and to apply the second acceleration mode when the length is longer than the predetermined length.

[0055] Furthermore, when the substrate S is thin, just as when the substrate S is light, if a sudden acceleration such as in the first acceleration mode is performed at the stage when the front end SF begins to transfer onto the conveyor belt 101, there is a risk that the substrate S will slip on the conveyor belt 101. For this reason, when the substrate S is thin, a gradual acceleration mode such as the second acceleration mode is appropriate. Conversely, when the substrate S is thick, the frictional force between the substrate S and the conveyor belt 101 increases, so by applying the first acceleration mode, it is possible to shorten the cycle time compared to the second acceleration mode. Therefore, it is preferable to apply the first acceleration mode when the thickness of the substrate S is equal to or greater than a predetermined thickness, and the second acceleration mode when the thickness is less than the predetermined thickness.

[0056] 6 and 7 are merely examples. For example, the second acceleration mode may be a mode in which the speed is increased stepwise rather than at a constant acceleration. For example, the second acceleration mode may be a mode in which the speed is increased stepwise, such as by accelerating from 50 to 100 mm / s and rotating for a certain period of time, and then accelerating from 100 to 150 mm / s and rotating for a certain period of time, and repeating this operation. Alternatively, the acceleration may be gradually increased rather than being constant.

[0057] (Switching Between the First Acceleration Mode and the Second Acceleration Mode) As described above, the control device 48 has two acceleration modes. The control device 48 switches between the first acceleration mode and the second acceleration mode based on the weight, thickness, and length of the board S to be transported in the board transport direction of the board S. The management PC 17 manages information about the boards S produced on the board production line 10 and transmits the information about the boards S to the board transport devices 11-15 in response to a so-called changeover, which changes the type of board S to be produced. This information about the board S includes, for example, information about the width of the board S in the case of the screen printing machine 12, and information about the type and mounting position of electronic components to be mounted in the case of the component mounter 13. In this embodiment, the management PC 17 stores the weight, thickness, and length of the board S in the board transport direction as information about the board S. Based on the predetermined reference values ​​described above, the management PC 17 determines the weight, thickness, and length of the board S to be produced next and determines which of the two acceleration modes should be used in the next production run. For example, the management PC 17 determines whether to execute the first acceleration mode if the weight of the substrate S is equal to or greater than a predetermined weight, and determines whether to execute the second acceleration mode if the weight is less than the predetermined weight. The management PC 17 determines whether to execute the first or second acceleration mode based on each of the weight, thickness, and length, and determines the acceleration mode to execute by a majority vote of the three determination results. For example, if the management PC 17 determines to execute the first acceleration mode based on the weight and thickness and the second acceleration mode based on the length, it determines the first acceleration mode as the acceleration mode for the next production run. The management PC 17 instructs the screen printing machine 12, etc., to execute the determined acceleration mode. This allows the control device 48 to execute an appropriate acceleration mode according to the weight, thickness, and length of the substrate S.

[0058] The above-described method for determining the acceleration mode is merely an example. For example, the management PC 17 may set a weighting coefficient for each of the weight, thickness, and length, and determine the next acceleration mode based on the sum of values ​​obtained by multiplying the weighting coefficient by the difference from the reference value. For example, if the coefficients for weight, thickness, and length are a1, a2, and a3, respectively, the judgment value is calculated using the following formula: Judgment Value = (Reference Weight - Board Weight) * a1 + (Reference Thickness - Board Thickness) * a2 + (Board Length - Reference Length) * a3. If the judgment value is negative, the first acceleration mode may be selected, and if the judgment value is positive, the second acceleration mode may be selected.

[0059] The management PC 17 may also determine the acceleration mode based on at least one parameter selected from the weight, thickness, and length. The acceleration mode may also be determined by a device other than the management PC 17, such as the screen printing machine 12 (control device 48). In this case, the control device 48 may acquire information about the substrate S from the management PC 17 before starting production of the next substrate S and determine the acceleration mode for the next production. The screen printing machine 12 may also have three or more acceleration modes. Specifically, the control device 48 may be configured to be switchable to an acceleration mode such as the acceleration mode of the second embodiment (see FIG. 9 ), which will be described later. The screen printing machine 12 may also be configured to be capable of executing only one of the first acceleration mode and the second acceleration mode. In other words, the acceleration mode may not be switchable.

[0060] Alternatively, the acceleration mode may be determined by an operator of board production line 10. For example, if the operator knows in advance that the board S is likely to slip on the conveyor belt (such as carry-in belt 131) in the previous process, the operator may manually select the second acceleration mode. When the board S is slipping, the actual movement speed of the board S is equal to or lower than the speed of the conveyor belt in the previous process, and therefore the board S becomes more likely to transfer when the belt speed (rotational speed V) of board transport devices 11-15 matches the actual board movement speed in the previous process (carry-in rotational speed VI).

[0061] Furthermore, depending on the substrate type or substrate lot, a conveyance error may occur when the substrate S becomes stuck and unable to transfer due to a step between the conveyor belts of the upstream and downstream processes. For example, in substrate types or substrate lots in which the front end SF of the substrate S tends to warp downward, the front end SF may fall into the gap between the upstream and downstream processes and become stuck on the step. For such substrate types or substrate lots, it is preferable to use the first acceleration mode to lift the substrate S by a sudden change, thereby facilitating transfer. When a conveyance error occurs, the operator may manually switch to the first acceleration mode. Alternatively, the control device 48 may automatically switch to the first acceleration mode when it detects that the substrate sensor 121 has been continuously ON for more than a predetermined time.

[0062] (Regarding the Board Sensor 121) As described above, when the board S is being carried in, the control device 48 positions the fixing unit 105 and the support base 98 at the transport position shown in FIG. 4 . After starting to carry in the board S, the control device 48 detects that the board S has been carried in to the printing position 44 based on the detection signal S2 of the board sensor 122 being turned on, and stops the rotation of the conveyor belt 101. The control device 48 drives the fixing unit lifting unit 96 and the support base lifting unit 97 to lift the fixing unit 105 and the support base 98 to the print execution position shown in FIG. 5 to perform printing. When printing of the solder paste is completed, the control device 48 lowers the fixing unit 105 and the like to the transport position and rotates the conveyor belt 101 to carry out the board S.

[0063] The control device 48 switches between a state in which the fixed unit lifting / lowering unit 96 and the support unit lifting / lowering unit 97 are permitted to lift and lower the conveyor belt 101 (fixed unit 105) and the support base 98, and a state in which the operation of the fixed unit lifting / lowering unit 96 and the support unit lifting / lowering unit 97 to lift and lower the fixed unit 105 and the like by the fixed unit lifting / lowering unit 96 and the support unit lifting / lowering unit 97 is restricted, depending on the detection state of the board S by the board sensor 122. For example, before the board S is carried in, the control device 48 prohibits the lifting / lowering operation because the detection signals S1 and S2 of the board sensors 121 and 122 are both off. The control device 48 also prohibits the lifting / lowering operation when the detection signal S1 is on, the board S begins to transfer to the conveyor belt 101, and the detection signal S2 is off. The control device 48 then permits the lifting operation after the rear end SR of the substrate S passes through the detection area 145, turning off the detection signal S1, and after the substrate S arrives at the printing position 44 and stops the conveyor belt 101 based on the on-state of the detection signal S2. For example, when the control device 48 prohibits the lifting operation described above, the control device 48 does not execute a process to raise the fixing unit 105 or the like even if that process occurs for some reason. Furthermore, when the control device 48 prohibits the lifting operation, the control device 48 does not execute the lifting operation even if the user manually operates the fixing unit 105 or the like to lift the fixing unit 105 or the like. Furthermore, after the substrate S arrives at the printing position 44 and stops the conveyor belt 101, that is, when the control device 48 permits the lifting operation, the control device 48 executes the lifting operation if there is a manual operation to lift the fixing unit 105 or the like. This prevents the substrate S from being damaged by the lifting operation, for example, if the substrate S stops at the carry-in entrance 43. Furthermore, the substrate sensor 121 that detects the entry of the substrate S can also be used as a substrate sensor for controlling the speed of the conveyor belt 101, thereby reducing the number of substrate sensors required for the screen printing machine 12. This reduces the manufacturing cost of the screen printing machine 12. Note that the control device 48 prohibits lifting and lowering operations when the substrate sensor 123 is on at the same time as the substrate sensor 121.

[0064] The above-described process of determining whether to permit the lifting operation based on the detection signals S1 and S2 is merely an example. For example, the control device 48 may prohibit the lifting operation when the detection signal S1 is in the ON state and permit the lifting operation when the detection signal S1 is in the OFF state. Furthermore, the control device 48 may implement a restriction process, such as slowing down the lifting speed, rather than completely prohibiting the lifting operation.

[0065] Incidentally, the correspondence between the terms used in this embodiment and those used in the claims will be explained below. The board transport device 11, screen printing machine 12, component mounter 13, reflow machine 14, inspection machine 15, and intermediate conveyors 21 to 25 of this embodiment are examples of board transport devices and pre-processing devices of the present disclosure. The servo motor 103 is an example of a drive source. The control command D1 is an example of a command. The support platform lifting unit 97 and the fixed unit lifting unit 96 are examples of lifting devices.

[0066] As described above, the embodiment described above provides the following advantages. In one aspect of this embodiment, the control device 48 controls the rotational speed V of the conveyor belt 101 to a first rotational speed V1 that is lower than the carry-in rotational speed VI of the intermediate conveyor 21 until the front end SF of the substrate S carried out from the carry-in belt 131 is transferred onto the conveyor belt 101. This ensures the frictional force required for the conveyor belt 101 to receive the substrate S, and allows the substrate S to be reliably transferred from the intermediate conveyor 21 to the conveyor belt 101. In other words, the occurrence of transfer errors of the substrate S can be suppressed. The control device 48 then accelerates the rotational speed V to carry in the substrate S in accordance with the timing TM2 at which the front end SF of the substrate S begins to transfer onto the conveyor belt 101. This allows the substrate S to be transferred more reliably, and then accelerates the speed after a portion of the substrate S has been transferred, thereby shortening the time required to carry in the substrate S. In particular, in a device that handles the substrate S before electronic components are placed thereon, such as the screen printing machine 12, the substrate S can be loaded at the faster second rotation speed V2. For this reason, it is extremely effective to apply the above-described speed control to the screen printing machine 12 that transports the substrate S before electronic components are placed thereon.

[0067] Second Example Next, a second example of the present disclosure will be described. In the first example described above, the rotation speed V is accelerated after a predetermined time T has elapsed after the front end SF is detected by the substrate sensor 121. In contrast, the second example differs from the first example in that acceleration begins upon detection without waiting for the predetermined time T to elapse. In the following description, the same components as those in the first example will be assigned the same reference numerals, and their description will be omitted as appropriate. The same applies to the third example.

[0068] 9 shows the relationship between the rotational speed V and time in the second embodiment. In the second embodiment, the control device 48 starts accelerating the servo motor 103 at timing TM1 when the substrate sensor 121 detects the leading end SF. For example, as in the second acceleration mode described above, the control device 48 accelerates the rotational speed V from the first rotational speed V1 to the second rotational speed V2 at a constant acceleration. Then, an acceleration is adopted such that the third rotational speed V3 at timing TM2 when the leading end SF begins to transfer onto (contact) the conveyor belt 101 is 100 mm / s or less, i.e., is less than the carry-in rotational speed VI of the intermediate conveyor 21 of the upstream process device.

[0069] Therefore, the control device 48 of the second embodiment controls the rotational speed V to be less than the loading rotational speed VI until the substrate sensor 121 detects the substrate S (until timing TM1). The control device 48 accelerates the rotational speed V at a constant acceleration from timing TM1 when the substrate sensor 121 detects the substrate S. Even with this speed control, the loading of the substrate S can be started at a third rotational speed V3 that is less than the loading rotational speed VI, allowing for smooth loading of the substrate S and shortening the loading time. Therefore, as in the first embodiment, the control device of the present disclosure may determine the timing when the front end of the substrate begins to transfer onto the conveyor belt (transfer) using the predetermined time T based on the detection by the substrate sensor of the substrate unloaded from the previous process device. Alternatively, as in the second embodiment, the control device of the present disclosure may start accelerating from the time of detection without determining the predetermined time T. That is, in the second embodiment, it is not necessary to determine the predetermined time T based on detection. In other words, it can be said that the control is performed such that the predetermined time T is set to zero.

[0070] Furthermore, the control in which the predetermined time T is set to zero is merely an example. For example, the board sensor 121 may be provided at a position above the conveyor belt 101, close to the upstream end 147 (see FIG. 8A). More specifically, for example, at the position where the front end SF of the board S carried out from the intermediate conveyor 21 first contacts the conveyor belt 101 (see FIG. 8C), an area where the front end SF can be detected may be set as the detection area 145 of the board sensor 121. Then, the control device 48 may accelerate the rotational speed V to the second rotational speed V2 at the timing when the detection signal S1 is turned on. Even with this control, acceleration can be started based on the detection of the board sensor 121 without using the predetermined time T. Therefore, the positions of the board sensors 121 to 123 in the first embodiment described above are merely an example.

[0071] Third Example Next, a third example of the present disclosure will be described. In the first example described above, the rotation speed V is controlled based on the detection signal S1 of the substrate sensor 121. In contrast, the third example differs from the first example in that the speed is controlled based on the discharge signal input from the intermediate conveyor 21.

[0072] FIG. 10 shows a screen printing machine 12A according to a third embodiment. The screen printing machine 12A does not include a substrate sensor 121. The control device 48 of the screen printing machine 12A receives a discharge signal S4 from a carry-in control device 136 of the intermediate conveyor 21. The carry-in control device 136 outputs the discharge signal S4 in response to the timing at which the substrate S is discharged. Therefore, the control device 48 of the third embodiment can receive the discharge signal S4 from the intermediate conveyor 21, indicating that the substrate S has been discharged. The method by which the carry-in control device 136 detects the timing at which the substrate S has been discharged is not particularly limited. For example, a sensor such as the substrate sensor 121 may be used, or a timer may be used to measure time. The control device 48 accelerates the rotational speed V after a predetermined time T2 has elapsed since the discharge signal S4 was received, as in the first embodiment. The predetermined time T2 is set to the time required from the time when the control device 48 inputs the carry-out signal S4 until the front end SF of the substrate S starts to transfer onto the conveyor belt 101 (reaching the state shown in FIG. 8(c)). This allows the screen printing machine 12A to determine the timing to accelerate the rotational speed V based on the carry-out signal S4 from the previous process device without using the substrate sensor 121. Therefore, the predetermined time T2 in the third embodiment is longer than the predetermined time T in the first embodiment if the configuration is the same as that of the first embodiment. More specifically, the predetermined time T2 can be set to the time from when the control device 48 inputs the carry-out signal S4 until the front end SF reaches the detection area 145, added to the predetermined time T.

[0073] For example, the control device 48 sets the rotation speed V to the first rotation speed V1 until it receives an unloading signal S4 indicating that the substrate has been unloaded. After receiving the unloading signal S4, the control device 48 maintains the first rotation speed V1 until a predetermined time T2 has elapsed. Then, for example, in the first acceleration mode, the control device 48 changes the rotation speed V from the first rotation speed V1 to the second rotation speed V2 after the predetermined time T2 has elapsed. Even when such speed control is performed, the substrate S can be smoothly loaded and the loading time can be shortened, as in the first embodiment.

[0074] The present disclosure can also be implemented by combining the configurations of the first to third embodiments. For example, the control device 48 may be capable of switching between an acceleration mode that uses the predetermined time T of the first embodiment and an acceleration mode that does not use the predetermined time T of the second embodiment. The control device 48 may also be configured to be capable of executing both speed control using the detection signal S1 of the substrate sensor 121 of the first embodiment and speed control using the unloading signal S4 of the third embodiment.

[0075] The present disclosure is not limited to the above-described embodiments, and various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. For example, the control device 48 may be configured to be capable of executing only one acceleration mode. Therefore, it is not necessary to switch modes based on the weight, length, and thickness of the substrate S. The screen printing machine 12 may be configured so that the substrate transport conveyor 92 (conveyor belt 101) cannot be raised or lowered.

[0076] The contents of the present disclosure are not limited to the dependent relationships described in the claims. For example, this specification also discloses the technical idea of ​​changing "the substrate transport apparatus according to claim 3" in claim 7 to "the substrate transport apparatus according to any one of claims 1 to 6." For example, this specification also discloses the technical idea of ​​changing "the substrate transport apparatus according to claim 2" in claim 8 to "the substrate transport apparatus according to any one of claims 2 to 7." For example, this specification also discloses the technical idea of ​​changing "the substrate transport apparatus according to claim 1" in claim 9 to "the substrate transport apparatus according to any one of claims 1 to 8." For example, this specification also discloses the technical idea of ​​changing "the substrate transport apparatus according to claim 2" in claim 10 to "the substrate transport apparatus according to any one of claims 2 to 9."

[0077] 11 Stocker (substrate transport device, front-end process device), 12, 12A Screen printing machine (substrate transport device, front-end process device), 13 Component mounting machine (substrate transport device, front-end process device), 14 Reflow machine (substrate transport device, front-end process device), 15 Inspection machine (substrate transport device, front-end process device), 21 to 25 Intermediate conveyor (substrate transport device, front-end process device), 48 Control device, 96 Fixation unit lifting unit (lifting unit), 97 Support table lifting unit (lifting unit), 101 Conveyor belt, 103 Servo motor (driving source), 121 Substrate sensor, 145 Detection area, 147 Upstream end, D1 Control command, S Substrate, SF Front end, S4 Carry-out signal, T, T2 Predetermined time, TM2 Timing, V Rotational speed, V1 First rotational speed, V2 Second rotational speed.

Claims

1. A substrate transfer device comprising: a conveyor belt for loading a substrate from a previous process device; a drive source for rotating the conveyor belt; and a control device for controlling the drive source to set the rotation speed of the conveyor belt to be equal to or lower than the speed at which the previous process device conveys the substrate until the front end of the substrate unloaded from the previous process device transfers onto the conveyor belt, and for accelerating the rotation speed of the conveyor belt in accordance with the timing at which the front end of the substrate unloaded from the previous process device transfers onto the conveyor belt, and for loading the substrate by the conveyor belt.

2. The substrate transfer device according to claim 1, further comprising a substrate sensor, wherein the control device accelerates the rotation speed of the conveyor belt in accordance with the timing at which the front end of the substrate transfers onto the conveyor belt based on the detection of the substrate unloaded from the previous process device by the substrate sensor.

3. The substrate sensor has a detection area for detecting the substrate at a position upstream of the upstream end of the conveyor belt in the substrate transfer direction of the substrate. The control device accelerates the rotation speed of the conveyor belt after a predetermined time has elapsed since the substrate was detected by the substrate sensor. The predetermined time is the time required for the front end of the substrate to transfer onto the conveyor belt since the substrate was detected by the substrate sensor. The substrate transfer device according to claim 2.

4. The control device executes a command to switch the rotation speed of the conveyor belt from a first rotation speed to a second rotation speed to the drive source in response to the elapse of a predetermined time since the substrate was detected by the substrate sensor. The second rotation speed is higher than the speed at which the previous process device conveys the substrate. The substrate transfer device according to claim 3.

5. The control device executes a command to accelerate the rotation speed of the conveyor belt from a first rotation speed to a second rotation speed at a constant acceleration to the drive source in response to the elapse of a predetermined time since the substrate was detected by the substrate sensor. The second rotation speed is higher than the speed at which the previous process device conveys the substrate. The substrate transfer device according to claim 3.

6. The substrate transfer device according to claim 4 or claim 5, wherein the first rotation speed is slower than the speed at which the previous process device transfers the substrate.

7. The control device is configured to execute a command to switch the rotation speed of the conveyor belt from the first rotation speed to the second rotation speed in response to the elapse of a predetermined time from the time when the substrate is detected by the substrate sensor, for the drive source, in a first acceleration mode; and to execute a command to accelerate the rotation speed of the conveyor belt from the first rotation speed to the second rotation speed at a constant acceleration and at an acceleration smaller than that in the first acceleration mode in response to the elapse of a predetermined time from the time when the substrate is detected by the substrate sensor, for the drive source, in a second acceleration mode. The control device is capable of executing these modes. The second rotation speed is faster than the speed at which the previous process device transfers the substrate. The control device switches between the first acceleration mode and the second acceleration mode based on at least one of the weight of the substrate to be transferred, the length of the substrate in the substrate transfer direction, and the thickness of the substrate. The substrate transfer device according to claim 3.

8. The substrate sensor is provided with a detection area for detecting the substrate at a position upstream of the upstream end of the conveyor belt in the substrate transfer direction of the substrate. The control device controls the drive source to keep the rotation speed of the conveyor belt lower than the speed at which the previous process device transfers the substrate until the substrate is detected by the substrate sensor, and accelerates the rotation speed of the conveyor belt at a constant acceleration from the time when the substrate is detected by the substrate sensor. The substrate transfer device according to claim 2.

9. The control device is capable of receiving an unloading signal indicating that the substrate has been unloaded from the previous process device, and accelerates the rotation speed of the conveyor belt after the elapse of a predetermined time from the time when the unloading signal is received. The predetermined time is the time required for the front end of the substrate to transfer onto the conveyor belt from the time when the unloading signal is received. The substrate transfer device according to claim 1.

10. The substrate conveying apparatus according to claim 2, further comprising a lifting device for lifting and lowering the conveyor belt, wherein the substrate sensor is set with a detection area for detecting the substrate at a position upstream of the upstream end of the conveyor belt in the substrate conveyance direction of the substrate, and the control device switches between a state in which the operation of lifting and lowering the conveyor belt is permitted to the lifting device and a state in which the operation of lifting and lowering the conveyor belt by the lifting device is restricted according to the detection state of the substrate by the substrate sensor.

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