Method and system for height correction of chip placement machine equipment based on vacuum pressure

Abstract

The present invention provides a method and system for height calibration of chip placement machine equipment based on vacuum pressure, the method includes the following steps: starting vacuum equipment to suck air to make vacuum pressure in Z axis, controlling Z axis to drive suction nozzle to move from the center position of the plane to be measured to the plane to be measured, stopping movement when detecting that the rate of change of vacuum pressure in Z axis is greater than a specified threshold, recording the position height to obtain a rough calibration result; selecting multiple measurement points with the rough calibration result as the center, controlling Z axis to move from top to bottom, detecting the vacuum pressure value in Z axis at the measurement point, judging the vacuum pressure difference value at adjacent measurement points, and ending calibration if it is greater than a predetermined threshold, the corresponding measurement point position height is the plane to be measured, and calibration is completed. The scheme is efficient and high-precision, as well as flexible and simple, meeting the requirements of mass production for speed and precision, as well as the production requirements of various types of components at different heights.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic manufacturing equipment, and in particular to a method and system for height correction of chip placement equipment based on vacuum pressure. Background Art

[0002] In the manufacturing process of modern electronic products, SMT machines (also known as surface mount technology equipment, SMT) are widely used to automatically mount various electronic components on printed circuit boards (PCBs). The accuracy and stability of the SMT machine directly determine the quality of the product, and a high degree of control is particularly important for the accurate absorption and placement of components.

[0003] Traditional placement equipment usually relies on mechanical sensors or fixed heights to control the nozzle's downward pressure and suction operations. These methods lack flexibility and precision when facing components of different heights, which can easily lead to component suction failure, inaccurate placement, and even component damage. In addition, mechanical sensors are limited by hardware accuracy and have certain measurement errors, which cannot guarantee the accuracy of the nozzle's contact with the component surface.

[0004] In order to improve the height accuracy of SMT equipment during component suction and placement, reduce errors and improve production efficiency, an automated and more accurate height calibration method is urgently needed. In the prior art, although some equipment uses technologies such as image recognition or laser ranging for height detection, these methods are highly complex and costly, and cannot fully meet the speed and accuracy requirements in mass production. Therefore, the present invention proposes a height calibration method for SMT equipment based on vacuum pressure detection, which monitors the vacuum pressure changes during the suction process of the suction nozzle to determine whether the suction nozzle is in contact with the component surface, and automatically completes the height calibration through a multi-step calibration process to achieve higher accuracy and efficiency. Summary of the invention

[0005] In order to solve the problems in the prior art, an object of the embodiments of the present invention is to provide a method and system for calibrating the height of a placement machine based on vacuum pressure.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for calibrating the height of a placement machine based on vacuum pressure, comprising the following steps:

[0007] Start the vacuum equipment to suck air to make the Z axis vacuum pressure, control the Z axis to drive the nozzle to move from the center position of the plane to be measured to the plane to be measured, and stop the movement when it is detected that the Z axis vacuum pressure change rate is greater than the specified threshold, and record the position height to obtain the rough calibration result;

[0008] Select multiple measuring points with the rough calibration result as the center, control the Z axis to move from top to bottom, detect the vacuum pressure value in the Z axis at the measuring point, and judge the vacuum pressure difference between adjacent measuring points. If it is greater than a predetermined threshold, the calibration is terminated, the height of the corresponding measuring point position is the plane to be measured, and the correction is completed.

[0009] Preferably, the vacuum device is started to suck air to make the Z-axis vacuum pressure, and the Z-axis driving nozzle is controlled to move from the center position of the plane to be measured to the plane to be measured, and the movement is stopped when it is detected that the rate of change of the vacuum pressure of the Z-axis is greater than a specified threshold, and the position height is recorded to obtain a rough calibration result. The specific process is as follows:

[0010] S11, control the Z axis to move to a specified safety height, and control the Z axis to move above the center position of the plane to be measured;

[0011] S12, start the vacuum equipment to generate negative pressure, then the Z axis starts to inhale air, and then control the Z axis to move toward the plane to be measured at a slower speed, and at the same time continuously monitor the vacuum pressure of the Z axis and the real-time position of the Z axis at S time intervals;

[0012] S13. When it is detected that the Z-axis vacuum pressure change rate is greater than the specified threshold, the Z-axis movement is stopped immediately, the vacuum equipment is controlled to stop generating negative pressure, the current Z-axis coordinate is recorded, and the Z-axis is controlled to move to a safe height to complete the rough calibration process.

[0013] Preferably, a plurality of measuring points are selected with the rough calibration result as the center, the Z axis is controlled to move from top to bottom, and the vacuum pressure values ​​in the Z axis at the measuring points are detected, specifically:

[0014] S21, control the Z axis to move to the specified safety height;

[0015] S22, taking the rough calibration result as the center and k as the movement step length, selecting n measurement points at the upper and lower positions of the rough calibration result, for a total of 2n+1 points;

[0016] S23, control the vacuum equipment to generate negative pressure, and the Z axis starts to inhale air;

[0017] S24, control the Z axis to move to the first measuring point, and read the vacuum pressure and Z axis coordinate once when it reaches the first measuring point;

[0018] S25, control the Z axis to move to the second measuring point, read the vacuum pressure and Z axis coordinate once, compare the vacuum pressure currently read with the vacuum pressure data of the previous measuring point, if the vacuum pressure difference exceeds the predetermined threshold, it is determined that the suction nozzle on the Z axis has contacted the plane to be measured, and the calibration is completed;

[0019] S26. After completing the calibration, record the final Z-axis coordinate as a precise calibration result, and move the Z-axis to a safe height.

[0020] Preferably, in step S5, if the predetermined threshold is not exceeded, the movement of subsequent measuring points is continued until the vacuum pressure difference value exceeds the predetermined threshold.

[0021] Preferably, steps S21-S26 are repeated multiple times to obtain multiple precise calibration results, and the average is taken as the final equipment height correction result.

[0022] Preferably, the vacuum equipment includes a vacuum generator and a vacuum pressure sensor, the vacuum generator is connected to the Z-axis and is used to generate negative pressure in the Z-axis; the vacuum pressure sensor is used to detect the vacuum pressure value in the Z-axis, and the vacuum pressure sensor is connected to the host computer and is used for the host computer to read the detected vacuum pressure value to monitor the contact state between the Z-axis and the plane to be measured.

[0023] Preferably, the method further includes, before rough calibration, initializing the placement machine system, starting the Z-axis and XY-axis control modules and performing a self-check to ensure that the equipment is in normal working condition, moving the Z-axis to a safe height away from the plane to be calibrated; and / or initializing the vacuum equipment, calibrating and testing the vacuum pressure sensor in the vacuum equipment to ensure that it can sensitively capture subtle changes in vacuum pressure.

[0024] A second aspect of the present invention provides a vacuum pressure-based chip placement machine equipment height correction system, comprising a component control module, a process control module, a data reading module, a data processing module, and a data storage module;

[0025] The component control module is used to control the Z axis, XY axis and vacuum equipment of the placement machine, receive the equipment control command issued by the process control module, and feedback the execution result;

[0026] The process control module is used to execute the above method steps to obtain the calibration results;

[0027] The data reading module is used to periodically read the vacuum pressure value and Z-axis coordinate monitored by the vacuum equipment during the execution of the process control module, analyze the read data, and send the data to the data processing module;

[0028] The data processing module is used to process and analyze the received vacuum pressure value and Z-axis coordinate, determine whether the suction nozzle on the Z-axis is in contact with the plane to be measured, and feed back the judgment result to the process control module;

[0029] The data storage module is used to store the correction result in a configuration file.

[0030] Preferably, it is used to calibrate the suction height of the placement machine, and / or the highest point of the platform, and / or the ATC height.

[0031] A third aspect of the present invention provides a computer-readable storage medium, on which a computer program or instruction is stored, and the computer program or instruction implements the method when executed by a processor.

[0032] Through the above technical scheme, by monitoring the vacuum pressure change of the suction nozzle under the suction state, it is determined whether the suction nozzle is in contact with the surface of the component. The calibration scheme based on the vacuum pressure change uses the system conditions of the placement machine itself to automatically complete the height correction. The method is flexible and simple, and the test accuracy is high. Compared with the traditional height correction method, the present invention has higher flexibility and applicability, can meet the requirements of various component specifications, and does not rely on external tools such as sensors, and has low difficulty and cost. A combination of rough calibration and fine calibration is adopted, and a more efficient calibration is achieved through a multi-step calibration process. The scheme of the present invention is efficient and high-precision, as well as flexible and simple, which meets the speed and accuracy requirements of mass production, as well as the production requirements of various types of components at different heights.

[0033] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0035] Figure 1 It is a flow chart of the height correction method of the chip mounter equipment based on vacuum pressure of the present invention;

[0036] Figure 2 is a rough calibration flow chart of an embodiment of the present invention;

[0037] Figure 3 is a flow chart of precise calibration according to an embodiment of the present invention;

[0038] Figure 4 It is an interactive schematic diagram of the vacuum pressure-based height correction system of the chip placement machine of the present invention. DETAILED DESCRIPTION

[0039] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0040] The first aspect of the embodiments of the present invention provides a method for calibrating the height of a placement machine based on vacuum pressure. The method is implemented using a control platform composed of a main control board, an XY sub-module, a placement head sub-module, and a device height calibration module. The main control board controls the movement of the XY sub-module and the placement head sub-module, and reads the vacuum pressure value and Z-axis coordinate data in the placement head sub-module to achieve the function of device height calibration. The main control board here uses a PCIe interface, and interacts with the host computer software through a Windows driver. In addition, the main control board is responsible for forwarding the commands issued by the host computer software to the XY sub-module and the placement head sub-module to control the corresponding component actions. Figure 1 As shown, the method comprises the following steps:

[0041] S1. System initialization: First, control the device to connect to the main control board, and initialize the placement head submodule and XY submodule to ensure that the device is in normal working condition. Move the Z axis to a safe height, away from the plane height that needs to be calibrated, to avoid any potential contact or damage risks.

[0042] S2. Initialize the vacuum system in the placement head module. The vacuum system includes a vacuum generator and a vacuum pressure sensor. Here, the feedback value of the vacuum pressure sensor needs to be calibrated. Combined with the theoretical ADC and kPa conversion formula, the offset is calibrated to make it more consistent with the actual vacuum pressure. After completion, install the suction nozzle for calibrating the equipment height on the Z axis to be used.

[0043] The vacuum pressure system includes a vacuum generator and a vacuum pressure sensor. The function of the vacuum generator is to generate negative pressure, so that suction is generated on the mounting head. The air pressure sensor is responsible for detecting the vacuum pressure value on the mounting head. The upper computer monitors the contact state between the Z axis and the plane to be measured by reading the vacuum pressure value detected by the vacuum pressure sensor. The Z axis is the axis used by the placement machine to mount components. During the calibration process, a suction nozzle needs to be installed on the Z axis. The suction nozzle can reduce the pores and increase the vacuum pressure value, so that the vacuum pressure change when contacting the plane to be measured is more obvious. In addition, the suction nozzle head is also equipped with a spring, which plays a buffering role, avoiding problems such as motor overcurrent caused by excessive downward pressure of the axis due to vacuum pressure detection delay. The XY axis is used to control the movement of the mounting head to the top of the plane to be measured.

[0044] S3, execute the rough calibration process to obtain the rough value of the height of the plane to be measured, such as Figure 2 As shown, the specific steps are as follows:

[0045] S3a, first control the Z axis to move to a safe height, and then control the XY axis to move above the plane to be measured, so that the Z axis is aligned with the center position of the plane to be measured;

[0046] S3b, start the vacuum equipment to generate negative pressure, turn on the vacuum pressure suction, then the Z axis starts to suck air, and then control the Z axis to move toward the plane to be measured at a slower speed, and at the same time continuously monitor the vacuum pressure of the Z axis and the real-time position of the Z axis at S time intervals;

[0047] The plane to be measured is used as the target position of the Z axis, and the target position is set as the positive limit of the Z axis. For example, the Z axis is controlled to move toward the plane to be measured at a speed of 10%, and at the same time, the vacuum pressure of the Z axis and the real-time position of the Z axis are continuously read and recorded at a time interval of 1 ms;

[0048] S3c. When it is detected that the Z-axis vacuum pressure change rate is greater than the specified threshold (i.e., the vacuum pressure jumps), the Z-axis movement is stopped immediately, the vacuum equipment is controlled to stop generating negative pressure, the current Z-axis coordinate at the time of the jump is recorded as the rough calibration result, and the Z-axis is controlled to move to a safe height to complete the rough calibration process.

[0049] S4. Select multiple measuring points with the rough calibration result as the center, control the Z axis to move from top to bottom, detect the vacuum pressure value in the Z axis at the measuring point, and judge the vacuum pressure difference between adjacent measuring points. If it is greater than a predetermined threshold, the calibration is terminated, and the height of the corresponding measuring point position is the plane to be measured, and the correction is completed.

[0050] Execute the fine calibration process. After completing the rough calibration process, a rough height result will be obtained. Since this result is measured during continuous descent, it will be affected by the delay of the vacuum pressure sensor and the data refresh interval, resulting in inaccurate results. Therefore, it is necessary to perform the fine calibration process based on the rough calibration. For example, the fine calibration process performs a 20µm step Z-axis segmented motion within the position range of [-500,500]µm centered on the rough calibration result. After each movement is in place, the vacuum pressure value and Z-axis position are read to find the position with a significant vacuum pressure difference relative to the previous position, and the fine calibration process is completed, such as Figure 3 As shown, the specific steps are as follows:

[0051] S4a, control the Z axis to move to a safe height;

[0052] S4b, taking the rough calibration result as the center and 20 µm as the movement step, select 2n+1 points before and after the rough calibration result, and select n as 25 measurement points for example, with a total of 51 points;

[0053] S4c, controlling the Z axis to rise to a safe height, the vacuum generator generates negative pressure to start vacuum pressure suction, and the Z axis starts to suction;

[0054] S4d, set the target position to the position of the point to be measured corresponding to the next coordinate, control the Z axis to descend, read the vacuum pressure and Z axis coordinate once after reaching the position, compare the vacuum pressure currently read with the vacuum pressure data of the previous point, if the vacuum pressure difference exceeds the predetermined threshold value T (i.e., a jump occurs), it is considered that the suction nozzle on the Z axis has contacted the plane to be measured, record the Z axis coordinate at this time as the result of precise calibration, and the calibration is completed. If it does not exceed the threshold, continue the movement of the subsequent points until a jump occurs;

[0055] S4e, after completing the calibration, record the final Z-axis coordinate as the result of the fine calibration, and move the Z-axis to a safe height;

[0056] S4f. Repeat steps S6a-S6e 5 times, and take the average of the 5 precise calibration results as the final equipment height calibration result.

[0057] Based on the same inventive concept, the second aspect of the embodiment of the present invention provides a vacuum pressure-based placement machine equipment height calibration system for calibrating the placement machine suction height, and / or the highest point of the platform, and / or the ATC height, such as Figure 4 As shown, it includes a component control module, a process control module, a data reading module, a data processing module and a data storage module;

[0058] The component control module is used to control the Z axis, XY axis and vacuum equipment of the placement machine, receive the equipment control command issued by the process control module, and feedback the execution result;

[0059] The process control module is used to execute the above method steps to obtain the calibration results;

[0060] The data reading module is used to periodically read the vacuum pressure value and Z-axis coordinate monitored by the vacuum equipment during the execution of the process control module, analyze the read data, and send the data to the data processing module;

[0061] The data processing module is used to process and analyze the received vacuum pressure value and Z-axis coordinate, determine whether the suction nozzle on the Z-axis is in contact with the plane to be measured, and feed back the judgment result to the process control module;

[0062] The data storage module is used to store the correction result in a configuration file.

[0063] The following are the actual calibration results obtained by using only the coarse calibration method and the coarse calibration + fine calibration method. The theoretical height of the plane to be measured is 57.6mm:

[0064] Number of tests Repeat rough calibration results (mm) Rough calibration + fine calibration results (mm) 1 57.552 57.522 2 57.453 57.523 3 57.508 57.521 4 57.396 57.522 5 57.478 57.523

[0065] From the above results, it can be concluded that the method of coarse calibration plus fine calibration can significantly improve the accuracy of correction and solve the uncertainty caused by fast stamping. In terms of time consumption, the time consumption of a single coarse calibration and fine calibration is about 5 seconds. Considering multiple measurements to avoid accidental errors, the total calibration time is within 30 seconds.

[0066] In summary, by monitoring the vacuum pressure change under the suction state of the suction nozzle, it is determined whether the suction nozzle is in contact with the surface of the component. The calibration scheme based on the vacuum pressure change uses the system conditions of the placement machine itself to automatically complete the height correction. The method is flexible and simple, and the test accuracy is high. Compared with the traditional height correction method, the present invention has higher flexibility and applicability, can meet the requirements of various component specifications, and does not rely on external tools such as sensors, and has low difficulty and cost. A combination of rough calibration and fine calibration is adopted, and a more efficient calibration is achieved through a multi-step calibration process. The scheme of the present invention is efficient and high-precision, as well as flexible and simple, which meets the speed and accuracy requirements of mass production, as well as the production requirements of various types of components at different heights.

[0067] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity, or apparatus.

[0068] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for height correction of chip placement machine equipment based on vacuum pressure, characterized in that: Used to calibrate the placement machine suction height, and / or the highest point of the platform, and / or the ATC height, including the following steps: Start the vacuum equipment to suck air to make the Z axis vacuum pressure, control the Z axis to drive the nozzle to move from the center position of the plane to be measured to the plane to be measured, and continuously monitor the vacuum pressure of the Z axis and the real-time position of the Z axis at S time intervals. When it is detected that the change rate of the vacuum pressure of the Z axis is greater than the specified threshold, stop the movement, record the position height to obtain the rough calibration result; Perform Z-axis segmented motion with a step length of 20µm in the position range of [-500,500]µm centered on the rough calibration result, select multiple measurement points centered on the rough calibration result, control the Z-axis to move from top to bottom, detect the vacuum pressure value in the Z-axis at the measurement point, and judge the vacuum pressure difference between adjacent measurement points. If it is greater than a predetermined threshold, the calibration is terminated, the height of the corresponding measurement point position is the plane to be measured, and the correction is completed.

2. The method according to claim 1, characterized in that The vacuum device is started to suck air to make the Z-axis vacuum pressure, and the Z-axis driving nozzle is controlled to move from the center position of the plane to be measured to the plane to be measured. When it is detected that the Z-axis vacuum pressure change rate is greater than a specified threshold, the movement is stopped, and the position height is recorded to obtain a rough calibration result. The specific process is as follows: S11, control the Z axis to move to a specified safety height, and control the Z axis to move above the center position of the plane to be measured; S12, start the vacuum equipment to generate negative pressure, then the Z axis starts to inhale air, and then control the Z axis to move toward the plane to be measured at a slower speed, and at the same time continuously monitor the vacuum pressure of the Z axis and the real-time position of the Z axis at S time intervals; S13. When it is detected that the Z-axis vacuum pressure change rate is greater than the specified threshold, the Z-axis movement is stopped immediately, the vacuum equipment is controlled to stop generating negative pressure, the current Z-axis coordinate is recorded, and the Z-axis is controlled to move to a safe height to complete the rough calibration process.

3. The method according to claim 1, characterized in that The method of selecting a plurality of measuring points with the rough calibration result as the center, controlling the Z axis to move from top to bottom, and detecting the vacuum pressure value in the Z axis at the measuring point is as follows: S21, control the Z axis to move to the specified safety height; S22, taking the rough calibration result as the center and k as the movement step length, selecting n measurement points at the upper and lower positions of the rough calibration result, for a total of 2n+1 points; S23, control the vacuum equipment to generate negative pressure, and the Z axis starts to inhale air; S24, control the Z axis to move to the first measuring point, and read the vacuum pressure and Z axis coordinate once when it reaches the first measuring point; S25, control the Z axis to move to the second measuring point, read the vacuum pressure and Z axis coordinate once, compare the vacuum pressure currently read with the vacuum pressure data of the previous measuring point, if the vacuum pressure difference exceeds the predetermined threshold, it is determined that the suction nozzle on the Z axis has contacted the plane to be measured, and the calibration is completed; S26. After completing the calibration, record the final Z-axis coordinate as a precise calibration result, and move the Z-axis to a safe height.

4. The method according to claim 3, characterized in that In step S25, if the predetermined threshold is not exceeded, the movement of subsequent measuring points is continued until the vacuum pressure difference value exceeds the predetermined threshold.

5. The method according to claim 3, characterized in that: Repeat steps S21-S26 multiple times to obtain multiple precise calibration results, and take the average as the final equipment height correction result.

6. The method according to any one of claims 1 to 5, characterized in that: The vacuum equipment includes a vacuum generator and a vacuum pressure sensor. The vacuum generator is connected to the Z-axis and is used to generate negative pressure in the Z-axis. The vacuum pressure sensor is used to detect the vacuum pressure value in the Z-axis. The vacuum pressure sensor is connected to the host computer and is used for the host computer to read the detected vacuum pressure value to monitor the contact state between the Z-axis and the plane to be measured.

7. The method according to claim 6, characterized in that The method also includes, before the rough calibration, initializing the placement machine system, starting the Z-axis and XY-axis control modules and performing a self-check to ensure that the equipment is in normal working condition, moving the Z-axis to a safe height away from the plane to be calibrated; and / or initializing the vacuum equipment, calibrating and testing the vacuum pressure sensor in the vacuum equipment to ensure that it can sensitively capture subtle changes in the vacuum pressure.

8. A vacuum pressure-based placement machine equipment height correction system, characterized in that: Used to calibrate the placement machine suction height, and / or the highest point of the platform, and / or the ATC height, including a component control module, a process control module, a data reading module, a data processing module and a data storage module; The component control module is used to control the Z axis, XY axis and vacuum equipment of the placement machine, receive the equipment control command issued by the process control module, and feedback the execution result; The process control module is used to execute the method steps as described in any one of claims 1 to 7 to obtain a correction result; The data reading module is used to periodically read the vacuum pressure value and Z-axis coordinate monitored by the vacuum equipment during the execution of the process control module, analyze the read data, and send the data to the data processing module; The data processing module is used to process and analyze the received vacuum pressure value and Z-axis coordinate, determine whether the suction nozzle on the Z-axis is in contact with the plane to be measured, and feed back the judgment result to the process control module; The data storage module is used to store the correction result in a configuration file.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instruction, and when the computer program or instruction is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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