Pressurizing device

Abstract

In this pressurizing device, damage to a workpiece is further reduced by improving response performance to feedback from a sensor that measures the value of pressure applied to the workpiece. A pressurizing device (1) applies a pressure having a target value to an object to be pressurized, the pressurizing device (1) comprising: an actuator (10) that pressurizes the object to be pressurized by linear motion converted from rotational motion of a motor (11) and driving a pressurizing portion (14) toward the object to be pressurized; a force sensor (15); and a motor driver (17) that controls the rotational direction and rotational speed of the motor (11). The value of the pressure applied to the object to be pressurized by the pressurizing portion (14) and measured by the force sensor (15) is input to the motor driver (17) as feedback.

Description

Pressing device

[0001] One aspect of the present invention relates to a pressing device.

[0002] A pressing device that applies a certain pressure to a workpiece such as a chiplet, which is a pressing object, in response to an instruction from a PLC (Programmable Logic Controller) is known. In Patent Document 1, a linear motor device that improves the accuracy of the load applied to a workpiece as a pressing object is disclosed.

[0003] Japanese Patent Application Laid-Open No. 2017-077051

[0004] However, in the prior art as described above, although the value of the pressure applied to the workpiece is input from the sensor as feedback to the PLC, there is room for improvement in that an excessive pressure can be applied instantaneously due to a time lag in reflecting the value of the pressure in the ongoing pressing process.

[0005] One aspect of the present invention aims to improve the response performance to the feedback from a sensor that measures the value of the pressure applied to a workpiece in a pressing device and further reduce damage to the workpiece.

[0006] In order to solve the above problems, a pressing device according to one aspect of the present invention is a pressing device that applies a pressure of a target value to a pressing object, and includes a motor and a pressing part that contacts the pressing object, and an actuator that performs pressing on the pressing object by a linear motion converted from the rotational motion of the motor and driving the pressing part toward the pressing object, and a force sensor that measures the value of the pressure applied by the pressing part to the pressing object, and a motor driver that controls the rotational direction and rotational speed of the motor. The motor driver receives, as feedback, the value of the pressure measured by the force sensor, which is the pressure applied by the pressing part to the pressing object.

[0007] Another aspect of the present invention is a pressurizing device for applying a target pressure to an object to be pressed, comprising: an actuator that applies pressure to the object to be pressed by linear motion driving the pressurizing part toward the object to be pressed, a force sensor that measures the value of the pressure applied by the pressurizing part toward the object to be pressed, and a motor driver that controls the linear motion of the pressurizing part, wherein the motor driver receives as feedback the value of the pressure applied by the pressurizing part toward the object to be pressed, which is the pressure measured by the force sensor, and the motor driver performs a process of temporarily suspending the process of increasing the pressure applied by the actuator, determining that the value of the pressure is within a predetermined range, and then resuming the process of increasing the pressure, one or more times between the time the pressurizing part comes into contact with the object to be pressed and the time when the value of the pressure applied by the pressurizing part toward the object to be pressed becomes substantially the same as the target value, and then resuming the process of increasing the pressure.

[0008] Another aspect of the present invention is a pressurizing device that applies a target pressure to an object to be pressed in response to instructions from a PLC (Programmable Logic Controller), comprising: an actuator that applies pressure to the object to be pressed by linear motion driving the pressurizing part toward the object to be pressed, a force sensor that measures the value of the pressure applied to the object by the pressurizing part, and a motor driver that receives instructions from the PLC and controls the linear motion of the pressurizing part, wherein the motor driver receives feedback from the PLC on the object to be pressed, with the value of the pressure measured by the force sensor being applied by the pressurizing part being input as feedback without going through the PLC.

[0009] According to one aspect of the present invention, the response performance to feedback from a sensor that measures the pressure applied to a workpiece in a pressurizing device can be improved, thereby further reducing damage to the workpiece.

[0010] This is an example of a block diagram showing the configuration of a pressurizing device. This is an example of an external view of a pressurizing device. This is an example of a flowchart showing the flow of the pressurizing process realized by the pressurizing device. This is an example of a diagram showing the pressure value measured by a force sensor.

[0011] One embodiment of the present invention will be described in detail below.

[0012] [1. Example of Pressure Device Configuration] Figure 1 is an example of a block diagram showing the configuration of the pressure device 1 according to this disclosure. The pressure device 1 is a device that performs a pressure processing process by applying a certain pressure to a workpiece, such as a chiplet, which is the object to be pressurized, based on instructions from a PLC (Programmable Logic Controller) 2. For example, the pressure processing can be performed in the placing (transfer) process in pick and place for the workpiece. Examples of workpieces include inductors, crystal oscillators, LEDs (Light Emitting Diodes), CMOS (Complementary Metal Oxide Semiconductor) sensors and image sensors, semiconductor chips, camera modules, MLCCs (Multilayer Ceramic Capacitors), and glass film sheets.

[0013] As shown in Figure 1, the pressurizing device 1 comprises a ball screw actuator 10, a motor driver 17, and an amplifier 18, and is connected to the PLC 2 via the motor driver 17. However, embodiments in which the PLC 2 is considered as part of the pressurizing device 1 are also included in this disclosure.

[0014] The ball screw actuator 10 comprises a ball screw device body 12 including a motor (z-axis motor) 11, and a head portion 13 including a pressurizing unit 14 and a θ-axis motor 16. The ball screw device body 12 is housed in a casing, and the screw shaft rotates due to the motor 11, causing the nut to slide along the screw shaft. The motor 11 and the θ-axis motor 16 are servo motors, and the pressurizing unit 1 can also be described as a servo press device. The following explanation will use the case shown in Figure 1, where the sliding direction of the nut indicated by arrow 21 is a vertical direction parallel to the z-axis, as an example, but the invention also includes the case where the nut slides in a horizontal direction. Furthermore, a ball is sandwiched between the surface of the screw shaft and the groove inside the nut, and this ball circulates inside the nut while contacting the surface of each groove as the nut moves along the screw shaft.

[0015] The head portion 13 is fixed to the nut of the ball screw device body 12 and moves in the z-axis direction together with the nut. The pressurizing portion 14 is a shaft or the like that contacts the workpiece. The pressurizing portion 14 can be rotated in the direction of arrow 22 by the θ-axis motor 16. The pressurizing portion 14 is equipped with a force sensor 15 for measuring the value of the pressure that the pressurizing portion 14 is applying to the workpiece. The force sensor 15 may include a strain gauge or the like. The provision of the force sensor 15 on the pressurizing portion 14 contributes to improving measurement accuracy. In addition, various end effectors may be attached to the tip of the pressurizing portion 14.

[0016] The motor driver 17 is a circuit device that supplies power to the motor 11 and the θ-axis motor 16, and controls the rotational speed and direction of the motor 11, etc., based on instructions input from the PLC 2. For example, the PLC 2 instructs the motor driver 17 of the ball screw actuator 10 to apply a certain target pressure to the workpiece, and the motor driver 17, in response to the instruction, controls the rotation of the motor 11 so that the head portion 13 moves in the z-axis direction at a specific speed.

[0017] The amplifier 18 amplifies the signal indicating the measurement result of the force sensor 15 and supplies it to the motor driver 17. In other words, in existing pressurizing devices using ball screw actuators, etc., the measurement result of the force sensor is supplied to the PLC as feedback, whereas in the pressurizing device 1 according to this disclosure, the measurement result of the force sensor 15 is supplied to the motor driver 17 as feedback. To put it another way, the motor driver 17 according to this disclosure is configured to receive the pressure value measured by the force sensor 15, which is the pressure applied by the pressurizing unit 14 to the workpiece, as feedback without going through the PLC 2 until it reaches a target value.

[0018] Furthermore, the motor driver 17 may be configured to temporarily suspend the process of increasing the pressure applied by the ball screw actuator 10 once or more between the time the pressurizing unit 14 contacts the workpiece and the time the pressure applied by the pressurizing unit 14 to the workpiece becomes approximately the same as the target value. After determining that the pressure value is within a predetermined range, the motor driver 17 may resume the process of increasing the pressure. In other words, the motor driver 17 may perform N-stage pressurizing processes (where N is a natural number of 2 or more).

[0019] Figure 2 is an example of an external view of the pressurizing device 1. Furthermore, Figure 28 on the left is an example of a perspective view, and Figure 29 on the right is an example of a side view. As illustrated in Figure 2, the ball screw device body 12 is often housed in a box-shaped enclosure. The force sensor 15 is housed in a separate box-shaped enclosure near the position indicated by the dotted line 27.

[0020] Furthermore, Figures 28 (left) and 29 (right) illustrate connectors 24 for connecting a cable that supplies power and control signals from the motor driver 17 to the motor 11 of the ball screw device body 12, connector 25 for connecting a cable that supplies power and control signals from the motor driver 17 to the θ-axis motor 16 of the head unit 13, and connector 26 for connecting a cable that supplies signals indicating the measurement results of the force sensor 15 to the amplifier 18. Note that at least one of the motor driver 17 and the amplifier 18 may be housed within their respective enclosures.

[0021] The above describes an example of the configuration of the pressurizing device 1. In addition, each part included in the pressurizing device 1 has the function of performing the processes described below.

[0022] [2. Processing Example 1 of the Pressurizing Device] Next, the flow of the pressurizing process realized by the pressurizing device 1 will be explained with reference to Figures 3 and 4. Figure 3 is an example of a flowchart showing the flow of the process. In this example, the motor driver 17 will explain the case in which it temporarily suspends the process of increasing the pressure and then resumes the process of increasing the pressure once, that is, when a two-stage pressurizing process is performed, until the value of the pressure applied by the pressurizing unit 14 to the workpiece becomes approximately the same as the target value. The motor driver 17 pressurizes until the value of the pressure applied by the pressurizing unit 14 to the workpiece reaches the first target load, and after determining that the value of the pressure is within a predetermined range, it pressurizes up to the second target load, which is the target value.

[0023] Figure 4 is a diagram illustrating the pressurization process, and is an example of a diagram showing the pressure value measured by the force sensor 15. In the graph of Figure 4, the horizontal axis corresponds to time, and the vertical axis corresponds to the pressure value.

[0024] In step S1, the PLC2 transmits information to the motor driver 17 of the ball screw actuator 10 indicating an instruction to apply a certain target pressure to the workpiece. Hereinafter, as an example, the target pressure will be assumed to be 70 N (Newtons).

[0025] In S2, the motor driver 17 controls the rotation of the motor 11 in response to instructions received from the PLC 2 and performs pressurization up to the first target load via the pressurizing unit 14. As the motor driver 17 moves the nut and head portion 13 of the ball screw device body 12 in the positive z-axis direction, the pressure applied by the pressurizing unit 14 to the workpiece gradually increases.

[0026] In the example shown in Figure 4, the first target load is 15 N. Each target load, including the first target load, may be calculated by the motor driver 17 by multiplying the target value by a predetermined coefficient, or a predetermined value for the target value may be stored in the motor driver 17's memory. Alternatively, each target load may be instructed by the PLC 2.

[0027] In step S3, the force sensor 15 measures the pressure applied to the workpiece by the pressurizing unit 14. The amplifier 18 amplifies the signal indicating the measurement result from the force sensor 15 and supplies it to the motor driver 17.

[0028] In S4, the motor driver 17 refers to the signal supplied from the amplifier 18 and determines whether the pressure applied by the pressurizing unit 14 to the workpiece has reached the first target load. If the motor driver 17 determines that the pressure has reached the first target load (S4: YES), it temporarily suspends the process of increasing the pressure, and then the process of S5 is executed. If it determines that the pressure has not reached the first target load (S4: NO), the pressurizing process from S2 is continued. In other words, the motor driver 17 continuously makes the determination in S4 from the start of the pressurizing process until the pressure reaches the first target load. The first target load can also be described as the target load used when the process of increasing the pressure applied by the ball screw actuator 10 to the workpiece is first temporarily suspended.

[0029] In S5, the motor driver 17 determines whether the pressure applied by the pressurizing unit 14 to the workpiece significantly exceeds the first target load by a first reference value, that is, whether the excess from the first target load exceeds the first reference value. Here, it is desirable that the first reference value and the second reference value, described later, are very small values ​​compared to the target value and each target load. Furthermore, the determinations in S4 and S5 can be rephrased as determining whether the pressure has reached the first target load and is outside a predetermined range defined by the first reference value. If the motor driver 17 determines that the pressure does not significantly exceed the first target load by a first reference value (S5: NO), that is, if it determines that the excess pressure is within the first reference value, the process in S6 is then executed. Furthermore, if the motor driver 17 determines that the pressure significantly exceeds the first target load by a first reference value (S5: YES), it adjusts the pressure and repeats the determination in S5 until it determines that the pressure does not significantly exceed the first target load by a first reference value.

[0030] Furthermore, a judgment of "YES" in S5 and in S9 described later corresponds to an overshoot exceeding each reference value. Here, overshoot refers to the phenomenon in which the device's response temporarily exceeds the target value. In the example in Figure 4, the overshoot when the pressurizing section 14 contacts the workpiece results in a pressure exceedance of 2.4 N relative to the first target load 15 N. However, the excess value of 2.4 N is smaller than that of the existing pressurizing device, where the measurement result of the force sensor is supplied to the PLC as feedback. Subsequently, in the example in Figure 4, after a temporary overshoot, the pressure value stabilizes at 15.2 N, resulting in a judgment of "NO" in S5.

[0031] Furthermore, when the excess pressure value from the first target load that may result from overshoot when the pressurizing section 14 contacts the workpiece is defined as the contact excess load, it is desirable that the first target load be set such that the difference between the target value and the first target load is greater than the contact excess load. In the example shown in Figure 4, the difference between the target value of 70 N and the first target load of 15 N, which is 55 N, is sufficiently larger than the contact excess load of 2.4 N. This prevents damage to the workpiece from occurring due to overshoot when the pressurizing section 14 contacts the workpiece.

[0032] Overshoot can also occur due to factors such as the impact when the pressurizing unit 14 comes into contact with the workpiece, the time lag in reflecting the pressure applied to the workpiece in the ongoing pressurizing process, vibrations around the pressurizing device 1, or the sliding resistance of the movable nut.

[0033] In S6, the motor driver 17 controls the rotation of the motor 11 to restart the pressurizing process, and pressurizes up to the second target load, i.e., the target value, via the pressurizing unit 14. As mentioned above, for example, the second target load is 70 N.

[0034] In step S7, the force sensor 15 measures the pressure applied to the workpiece by the pressurizing unit 14. The amplifier 18 amplifies the signal indicating the measurement result from the force sensor 15 and supplies it to the motor driver 17.

[0035] In S8, the motor driver 17 refers to the signal supplied from the amplifier 18 and determines whether the pressure applied by the pressurizing unit 14 to the workpiece has reached the second target load. If the motor driver 17 determines that the pressure has reached the second target load (S8: YES), it temporarily suspends the process of increasing the pressure, and then the process in S9 is executed. If it determines that the pressure has not reached the first target load (S8: NO), the pressurizing process from S6 is continued. In other words, the motor driver 17 continues to make the determination in S8 from the time the pressurizing process is resumed until the pressure reaches the second target load.

[0036] In S9, the motor driver 17 determines whether the pressure applied by the pressurizing unit 14 to the workpiece significantly exceeds the second target load and the second reference value, that is, whether the excess from the second target load exceeds the second reference value. The determinations in S8 and S9 can also be rephrased as determining whether the pressure has reached the second target load and is outside a predetermined range defined by the second reference value. If the motor driver 17 determines that the pressure does not significantly exceed the second target load and the second reference value (S9: NO), that is, if it determines that the excess pressure is within the second reference value, the process in S10 is then executed. If the motor driver 17 determines that the pressure significantly exceeds the second target load and the second reference value (S9: YES), it adjusts the pressure and repeats the determination in S9 until it determines that the pressure does not significantly exceed the second target load and the second reference value. In the example shown in Figure 4, the pressure value stabilizes at approximately 70.1N, which is nearly identical to the target value of 70N, with almost no overshoot, resulting in a "NO" judgment in S9. This is because the overshoot that occurred when the pressurizing unit 14 contacted the workpiece was addressed at the point of pressurizing up to the first target load in S4 and S5, and virtually no other overshoot occurred during pressurizing up to the second target load, which is the target value.

[0037] In S10, the motor driver 17 controls the rotation of the motor 11 to terminate the pressurizing process, moving the nut and head portion 13 in the opposite direction to the workpiece, i.e., in the negative z-axis direction. As a result, the pressure applied to the workpiece returns to 0N, as shown in the example in Figure 4.

[0038] The above describes the flow of the pressurization process realized by the pressurization device 1. According to the process in this example, compared to existing pressurization devices, the response performance to feedback from the force sensor 15, which measures the pressure applied to the workpiece in the pressurization device 1, can be improved, similar to a spinal reflex in the human body. This reduces damage to the workpiece and has the effect of improving the yield of workpieces in a production line, for example.

[0039] [4. Additional Notes] In the example described above, a ball screw actuator 10 was used as an example, but the actuators to which the configuration described herein can be applied, in which the pressure applied by the pressurizing unit 14 to the workpiece and the pressure value measured by the force sensor 15 is input to the motor driver 17 as feedback without going through the PLC 2 until the target value is reached, are not limited to this. For example, the above configuration is also applicable to other actuators that include a motor 11 and a pressurizing unit 14 that contacts the workpiece, and apply pressure to the workpiece by linear motion converted from the rotational motion of the motor 11, which drives the pressurizing unit 14 toward the workpiece. Specifically, the actuator of the pressurizing device 1 may be an actuator that drives the pressurizing unit 14 by ball screw drive or belt drive, etc. Furthermore, the above configuration is also applicable to other actuators that apply pressure to the workpiece by linear motion that drives the pressurizing unit 14 toward the workpiece. Specifically, the actuator of the pressurizing device 1 may be a linear motor driven actuator in which the movable element moves due to the interaction between a permanent magnet and an electromagnet.

[0040] Furthermore, as mentioned above, the motor driver 17 may perform N-stage pressurization (where N is a natural number of 2 or more). In this case, the motor driver 17 performs i-th stage pressurization (where i is a natural number from 1 to N), and after determining that the pressure applied by the pressurization unit 14 to the workpiece has reached the i-th target load and that the excess pressure is within the i-th reference value, if i < N, it performs i+1 stage pressurization. In addition, some or all of the reference values ​​may be the same as each other, or they may be defined according to the type of workpiece.

[0041] Furthermore, the process by which the motor driver 17 reflects the pressure value acquired without going through the PLC 2 into the ongoing pressurization process is not limited to controlling the rotation of the motor 11, but can also be applied to controlling the rotation of the θ-axis motor 16. In a broader sense, the above-mentioned explanation for the motor 11 can also be applied to the θ-axis motor 16. Note that it is not essential for the pressurization device 1 to include the θ-axis motor 16 or the amplifier 18.

[0042] 1. Pressurizing device 2. PLC (Programmable Logic Controller) 10. Ball screw actuator 11. Motor (z-axis motor) 12. Ball screw device body 13. Head unit 14. Pressurizing unit 15. Force sensor 16. θ-axis motor 17. Motor driver 18. Amplifier

Claims

1. A pressurizing device for applying a target pressure to an object, comprising: a motor; a pressurizing part that contacts the object, and an actuator that applies pressure to the object by linear motion converted from the rotational motion of the motor, which drives the pressurizing part toward the object; a force sensor that measures the value of the pressure applied by the pressurizing part to the object; and a motor driver that controls the rotation direction and rotation speed of the motor, wherein the motor driver receives as feedback the value of the pressure applied by the pressurizing part to the object, which is the pressure measured by the force sensor.

2. The pressurizing device according to claim 1, wherein the motor driver temporarily suspends the process of increasing the pressure applied by the actuator once or more times between the time the pressurizing unit comes into contact with the object to be pressed and the time the value of the pressure applied by the pressurizing unit to the object to be pressed becomes substantially the same as the target value, determines that the value of the pressure is within a predetermined range, and then resumes the process of increasing the pressure.

3. The pressurizing device according to claim 2, wherein the motor driver temporarily suspends the process of increasing the pressure applied by the actuator when the pressure applied by the pressurizing unit to the object reaches each target load, the target load used when the process of increasing the pressure applied by the actuator is first temporarily suspended is defined as the first target load, and the excess pressure value from the first target load that may result from overshoot when the pressurizing unit contacts the object is defined as the contact excess load, the first target load is set such that the difference between the target value and the first target load is greater than the contact excess load.

4. The pressurizing device according to claim 1 or 2, wherein the target value is a value corresponding to an instruction input from a PLC (Programmable Logic Controller) to the motor driver, and the motor driver receives the pressure value measured by the force sensor as feedback without going through the PLC.

5. The pressurizing device according to claim 1 or 2, wherein the actuator is an actuator that drives the pressurizing section by ball screw drive or belt drive.

6. The pressurizing device according to claim 1 or 2, wherein the pressurizing portion is a shaft on which the force sensor is provided.

7. A pressurizing device for applying a target pressure to an object to be pressed, comprising: an actuator that applies pressure to the object by linear motion driving the pressurizing part toward the object, the actuator having a pressurizing part that contacts the object to be pressed; a force sensor that measures the value of the pressure applied by the pressurizing part toward the object to be pressed; and a motor driver that controls the linear motion of the pressurizing part, wherein the motor driver receives as feedback the value of the pressure applied by the pressurizing part toward the object to be pressed, which is the pressure measured by the force sensor, and the motor driver performs a process of temporarily suspending the process of increasing the pressure applied by the actuator once or more times between the time the pressurizing part comes into contact with the object to be pressed and the time when the value of the pressure applied by the pressurizing part toward the object to be pressed becomes substantially the same as the target value, and then resuming the process of increasing the pressure after determining that the value of the pressure is within a predetermined range.

8. A pressurizing device that applies a target pressure to an object to be pressed in accordance with instructions from a PLC (Programmable Logic Controller), comprising: an actuator that applies pressure to the object by linear motion driving the pressurizing part toward the object, the actuator having a pressurizing part that contacts the object to be pressed; a force sensor that measures the value of the pressure applied to the object by the pressurizing part; and a motor driver that receives instructions from the PLC and controls the linear motion of the pressurizing part, wherein the motor driver receives feedback of the pressure applied to the object by the pressurizing part and the value of the pressure measured by the force sensor, without going through the PLC.

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