Method for automatically calibrating suction nozzle of high-speed chip mounter without shutdown

Abstract

The invention discloses a method for automatically calibrating a suction nozzle of a high-speed chip mounter without shutdown, which is characterized in that a suction nozzle correction station is additionally arranged beside a suction nozzle exchange station of the high-speed chip mounter, and a correction sheet placed at a starting position is placed at the suction nozzle correction station; after the upper computer program detects that the suction nozzle exchange station completes the action of replacing the suction nozzle, the upper computer program automatically corrects the newly replaced suction nozzle through the correction function without shutdown, automatically switches to a mounting working state and automatically compensates and calibrates the newly replaced suction nozzle in real time; after the suction nozzles are replaced, the high-speed chip mounter automatically corrects the newly-replaced suction nozzles in a full-automatic non-stop mode, operator intervention or manual operation is not needed, shutdown is not needed in the high-speed chip mounting process, the original working state is automatically switched to and the original mounting work continues after the suction nozzles are corrected, the correction process is full-automatic, simple, convenient and rapid, and the efficiency is high. The correction speed is fast, and the efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed placement machines, in particular to a method for automatically calibrating a suction nozzle of a high-speed placement machine without stopping the machine. Background Art

[0002] During the placement process of a high-speed placement machine, the concentricity of the nozzle is one of the important factors affecting the placement accuracy. This is mainly manifested in that after the placement angle is rotated, the center of the component on the nozzle will shift due to the offset of the nozzle center, which will affect the deviation of the final placement position.

[0003] Conventional methods for calibrating the concentricity of suction nozzles are manual visual inspection and sample placement calibration. Both require manual intervention and are time-consuming. In addition, long-term vibration, mechanical wear, etc. will further affect the accuracy of the suction nozzle. Therefore, it is difficult to manually calibrate each suction nozzle during the actual production process. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for automatically calibrating the suction nozzle of a high-speed placement machine without stopping the machine, which solves the problem of reduced overall placement accuracy caused by errors in the center of the suction nozzle through automatic correction.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: a method for automatically calibrating the nozzle of a high-speed placement machine without stopping the machine,

[0006] A nozzle calibration station is added next to the nozzle exchange station of the high-speed placement machine. The nozzle calibration station is equipped with a calibration sheet placed in the starting position. After the upper computer program detects that the nozzle exchange station has completed the nozzle replacement action, the upper computer program automatically calibrates the newly replaced nozzle through the calibration function without stopping the machine, automatically switches to the placement working state, and automatically compensates and calibrates the newly replaced nozzle in real time, including the following steps:

[0007] Select the calibration sheet pickup step, select the corresponding calibration sheet at the nozzle calibration station, move the nozzle to the top of the nozzle calibration station, and move the nozzle until the XY center deviation between the center of the newly replaced nozzle and the center of the currently selected calibration sheet at the starting position is ≤±0.5mm. The newly replaced nozzle descends and picks up the selected calibration sheet.

[0008] Data recording step: The host computer program controls the suction nozzle that picks up the calibration sheet to move to the high-definition camera, calls the visual recognition processing program to identify the current center coordinates (X0, Y0) of the calibration sheet, and intermittently rotates the calibration sheet, each rotation angle is 45°, until the total rotation angle is equal to or greater than 360°. After each rotation of 45°, the visual recognition processing program is used to identify the current center coordinates of the calibration sheet. The host computer program records the data of the center coordinates of the eight sets of calibration sheets obtained;

[0009] Verification step: Control the newly replaced suction nozzle to put the calibration piece back to the corresponding starting position, call the visual recognition processing program again to identify the center coordinates of the calibration piece, compare the XY center deviation distances of the front and rear center coordinates of the calibration piece, and if the X center deviation distance is ≤ ±0.5mm and the Y center deviation distance is ≤ ±0.5mm, the recorded data is determined to be valid. Otherwise, the calibration piece selection, data recording and verification steps are repeated until the recorded data is determined to be valid. 8 sets of valid data of the calibration piece center coordinates are recorded.

[0010] Establish a correction curve step, establish an interpolation formula with angle as variable composed of 8 sets of valid data for the newly replaced nozzle, and construct a correction curve P of the rotation angle of the newly replaced nozzle and the nozzle X direction deviation x (θ) and the correction curve P of the rotation angle of the newly replaced nozzle and the deviation of the nozzle in the Y direction y (θ), the nozzle correction curve is constructed.

[0011]

[0012] The nozzle calibration curve is saved in the host computer program, and the automatic calibration process of the newly replaced nozzle is automatically completed;

[0013] The automatic calibration step is not stopped. After the automatic calibration process is completed, the upper computer program automatically switches to the placement working state. In the placement working state, the upper computer program automatically compensates and calibrates the newly replaced nozzle in real time according to the nozzle calibration curve.

[0014] For the target position (X, Y), the actual position after the correction and compensation of the instruction with a rotation angle of β (target position XP x (β), target position YP y (β)).

[0015] A further technical solution includes the following steps:

[0016] Step S1: The nozzle calibration station is provided with a black calibration plate as a background. The calibration plate is a white ceramic calibration plate. Arranged on the calibration plate are multiple ceramic calibration plates of different models and sizes for detecting nozzles of different length and width sizes. The length and width sizes of the ceramic calibration plates include but are not limited to 1x1mm, 2x2mm, 3x3mm, 4x4mm, and 5x5mm. Each ceramic calibration plate is placed at the corresponding starting position.

[0017] Step S2: After the host computer program of the high-speed placement machine detects that the nozzle exchange station has completed the nozzle replacement action, the host computer program automatically executes steps S3 to S8 once through the correction function, automatically calibrates the newly replaced nozzle without stopping the machine, automatically switches to the placement working state after the automatic correction process is completed, and automatically executes step S9 during the automatic placement working process, automatically calibrating the newly replaced nozzle in real time;

[0018] Step S3: The upper computer program controls the newly replaced nozzle to move to the top of the nozzle calibration station and selects the calibration piece with the actual center coordinate of the corresponding model;

[0019] Step S4: Align the center of the newly replaced nozzle with the center of the currently selected calibration piece at the starting position and the XY center deviation distance is ≤ ±0.5mm.

[0020] The implementation steps are as follows: controlling the head camera of the high-speed placement machine to move to the top of the corresponding calibration plate, using the head camera to shoot the calibration plate and obtain a first image; the host computer program calls the visual recognition processing program to automatically visually recognize the first image and identify the current center coordinates (X c ,Y c ),

[0021] The host computer program then controls the head camera to move in the X and Y directions, and compares the actual center coordinates with the recognized center coordinates (X c ,Y c ) in the center deviation distance in the XY direction,

[0022] When the X center deviation distance is less than or equal to ±0.5mm and the Y center deviation distance is less than or equal to ±0.5mm, the head camera is stopped from moving and the current center coordinates (X c ,Y c );

[0023] Step S5: The upper computer program controls the newly replaced suction nozzle to descend and suck up the corresponding calibration piece;

[0024] Step S6: The upper computer program controls the newly replaced suction nozzle that sucks the calibration sheet to move to the high-definition camera of the high-speed placement machine, and moves the calibration sheet to the top of the high-definition camera of the high-speed placement machine.

[0025] Use a high-definition camera to shoot the calibration film and obtain a second image. The host computer program calls the visual recognition processing program again to perform visual recognition on the second image and identify the current center coordinates (X0, Y0) of the calibration film being sucked.

[0026] Control the intermittent rotation of the nozzle rod and drive the newly replaced nozzle installed on the nozzle rod and the calibration piece sucked by the nozzle to rotate intermittently, with each rotation angle being 45° until the total rotation angle is equal to or greater than 360°. After each rotation of 45°, the current center coordinates of the calibration piece are respectively identified by the visual recognition processing program, and the upper computer program records the obtained data of the center coordinates of 8 sets of calibration pieces;

[0027] Step S7: The upper computer program controls the newly replaced nozzle to move to the nozzle calibration station, controls the nozzle to move the calibration sheet to the corresponding starting position of the calibration sheet and releases it, and puts the calibration sheet back to the corresponding starting position.

[0028] The host computer program uses the head camera to shoot the calibration piece again, and calls the visual recognition processing program again to identify and obtain the current center coordinates (X c ’ ,Y c ’ ), and compare the center coordinates (X c ’ ,Y c ’ ) and the XY center deviation distance of the actual center coordinate, or compare the center coordinates (X c ,Y c ) and the center coordinates (X c ’ ,Y c ’ )’s XY center deviation distance,

[0029] If the X center deviation distance is less than or equal to ±0.5mm and the Y center deviation distance is less than or equal to ±0.5mm, the recorded data is determined to be valid. Otherwise, repeat steps 3 to 6 until the recorded data is determined to be valid.

[0030] Step S8: The host computer program combines the interpolation formula and the 8 sets of valid data obtained by recording, takes the angle as the variable, and obtains an interpolation formula consisting of 8 sets of data for the newly replaced nozzle, which is recorded as the correction curve P of the rotation angle of the newly replaced nozzle and the nozzle X-direction deviation. x (θ) and the correction curve P of the rotation angle of the newly replaced nozzle and the deviation of the nozzle in the Y direction y (θ), the nozzle calibration curve is constructed,

[0031]

[0032] The nozzle calibration curve is saved in the host computer program, and the automatic calibration of the newly replaced nozzle is automatically completed;

[0033] Step S9: Automatic compensation calibration without stopping the machine.

[0034] After completing step S8, the host computer program automatically switches to the placement working state. In the placement working state, the host computer program automatically compensates and calibrates the newly replaced nozzle in real time according to the nozzle calibration curve.

[0035] For the target position (X, Y), the actual position after the correction and compensation of the instruction with a rotation angle of β (target position XP x (β), target position YP y (β)).

[0036] In a further technical solution, in step S9, the host computer program performs deviation compensation on the target position (X, Y) of the newly replaced nozzle based on the correction curve in the X direction and the correction curve in the Y direction and calculates the actual position of the newly replaced nozzle. When the newly replaced nozzle rotates the corresponding angle β and reaches the target position, the host computer program calculates the actual position of the newly replaced nozzle (target position XP x (β), target position YP y (β)), control the newly replaced nozzle to move to the calculated actual position (target position XP x (β), target position YP y (β)).

[0037] In a further technical solution, in step S2, the host computer program automatically selects a calibration sheet of a corresponding model, and a dot matrix code representing the nozzle is provided on the surface of each nozzle.

[0038] After the upper computer program detects the nozzle replacement operation at the nozzle exchange station, the upper computer program uses any camera to capture the dot matrix code of the newly replaced nozzle, uploads the recognition result of the dot matrix code to the calibration function, and automatically determines and selects the corresponding model of the calibration film based on the nozzle information in the nozzle library and the corresponding matching calibration film information, and reads and obtains the actual center coordinates of the calibration film;

[0039] In step S3, the newly replaced suction nozzle is moved to the top of the calibration station and then the suction nozzle rod is controlled to rotate to the zero point, so as to rotate the newly replaced suction nozzle to the zero position.

[0040] In a further technical solution, the step of automatically selecting a correction film,

[0041] Set the pixel range of the head camera to (W pix ,H pix ), pixel accuracy is R s , set the length and width of the currently selected identification correction piece (W p ,H p ),

[0042] The host computer program calculates the size of the calibration piece currently identified below the newly replaced nozzle based on the visual recognition result of the visual recognition processing program and is (R s *W1, R s *H1),

[0043] The upper computer program matches and compares the calibration piece size of the currently identified calibration piece with the calibration piece information stored in the nozzle library, and determines whether the currently identified calibration piece is the calibration piece of the corresponding model corresponding to the newly replaced nozzle. If it does not match, the next calibration piece is rescanned and identified. If it matches, the currently identified calibration piece is determined to be the calibration piece of the corresponding model and the calibration piece is selected for automatic correction.

[0044] In a further technical solution, in step S4, the host computer program controls the head camera to move in the X and Y directions respectively, and calculates the deviation distances ΔX and ΔY of the center coordinates of the calibration plate at the starting position in real time during the movement.

[0045] ΔX=(X c -W pix / 2)*R s , ΔY=(Y c -H pix / 2)*R s ,

[0046] When the calculated results are ΔX≦±0.5mm and ΔY≦±0.5mm, stop moving the head camera and record the current center coordinates (X c ,Y c );

[0047] In step S7, the host computer program controls the head camera to move in the X and Y directions respectively, and calculates the deviation distance ΔX of the current center coordinate of the correction piece put back to the starting position in real time during the movement. ’ and ΔY ’ ,

[0048] ΔX ’ =(X c ’ -W pix / 2)*R s , ΔY ’ =(Y c ’ -H pix / 2)*R s ,

[0049] Until the calculated result is ΔX ’ ≦±0.5mm and ΔY ’When the head camera is less than ±0.5 mm, stop moving the camera and record the center coordinates (X c ’ ,Y c ’ ).

[0050] In a further technical solution, the movement speed of the correction plate is no greater than 0.1 times the movement speed of the high-speed placement machine during normal placement.

[0051] In a further technical solution, the step S8:

[0052] The correction curves in the X and Y directions are calculated using the Lagrange interpolation formula with the angle θ as the variable.

[0053]

[0054] Calculate 8 sets of valid data i (θ), we can get,

[0055]

[0056] In a further technical solution, the correction curves in the X and Y directions are substituted to construct the nozzle correction curve.

[0057] When replacing a plurality of the suction nozzles at one time, each suction nozzle is automatically calibrated in turn and a corresponding suction nozzle calibration curve is constructed.

[0058] Compared with the prior art, the present invention has the following advantages: the high-speed placement machine performs a visual automatic correction on the concentricity of the newly replaced suction nozzle each time a new suction nozzle is replaced, thereby solving the problem of reduced overall placement accuracy due to errors in the center of the suction nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a flow chart of nozzle calibration of the present invention. DETAILED DESCRIPTION

[0060] A method for automatically calibrating the nozzle of a high-speed placement machine without stopping the machine. Figure 1 As shown, the following steps are included:

[0061] Step S1: The nozzle calibration station is provided with a black calibration plate as a background, and a white ceramic calibration plate is selected as the calibration piece. A plurality of ceramic calibration pieces of different models and sizes for detecting nozzles of different length and width sizes are arranged on the calibration plate. The calibration piece is fixed on the calibration plate by negative pressure adsorption. Each calibration piece has its own starting position and the actual center coordinates at the starting position. The actual center coordinates of each calibration piece are stored in the host computer for the host computer program to call.

[0062] The length and width specifications of the ceramic calibration sheets include but are not limited to 1x1mm, 2x2mm, 3x3mm, 4x4mm and 5x5mm. Each ceramic calibration sheet is placed at the corresponding starting position. Calibration sheets of various sizes are configured at the nozzle calibration station to detect nozzles of different sizes. For example, a 1x1mm calibration sheet is used for nozzles that absorb packages below R0805 to prevent the nozzle from being unstable during absorption due to the weight of the calibration sheet, thereby avoiding measurement errors.

[0063] Step S2: After the upper computer program of the high-speed placement machine detects that the nozzle exchange station has completed the action of replacing the nozzle, the upper computer program automatically executes steps S3 to S8 once through the correction function, and automatically corrects the newly replaced nozzle without stopping the machine. After completing the automatic correction process, it automatically switches to the placement working state, automatically continues the placement work with the placement progress before the nozzle was replaced, and automatically executes step S9 during the automatic placement work process to automatically calibrate the newly replaced nozzle in real time.

[0064] The present invention utilizes dual vision systems for mutual verification, which has the advantage of more accurate and reliable correction. The deviation of the center of the nozzle is determined by detecting the position change when the nozzle picks up the calibration piece under visual recognition, and the deviations at all angles are fitted into a regression curve for the SMT high-speed placement machine to adjust the deviation position in real time during actual placement, reducing the risk of accuracy changes caused by replacing the nozzle.

[0065] The high-speed placement machine drives the nozzle rod to move or rotate according to instructions through the driving element, and the nozzle is installed on the nozzle rod for sucking components. The high-speed placement machine is equipped with cameras such as a head camera and a high-definition camera. The high-speed placement machine (host computer) runs a host computer program and a visual recognition processing program. The host computer program controls various operations of the high-speed placement machine, including controlling the driving element to drive the nozzle rod to move or rotate, suck or release components. The visual recognition processing program combines the head camera and the high-definition camera and other cameras to perform intelligent visual recognition, including automatic identification of components and identification and calculation to obtain the center coordinates of the components. The present invention calls the existing visual recognition processing program through the correction function to perform visual recognition on the correction piece and identify and calculate the center coordinates of the correction piece.

[0066] The upper computer program automatically selects the calibration film of the corresponding model. The surface of each nozzle is provided with a dot matrix code representing the nozzle. After the upper computer program detects the nozzle replacement operation at the nozzle exchange station, the upper computer program uses any camera to shoot the dot matrix code of the newly replaced nozzle and uploads the recognition result of the dot matrix code to the correction function. The upper computer is provided with a nozzle library, which stores the information of each nozzle and the corresponding matching calibration film information. The upper computer program automatically determines and selects the corresponding model of calibration film according to the nozzle information in the nozzle library and the corresponding matching calibration film information.

[0067] The specific steps of automatically selecting the correction film are to set the pixel range of the head camera to (W pix ,H pix ), pixel accuracy is R s , set the length and width of the currently selected recognition correction piece (W p ,H p ), the upper computer program calculates the size of the calibration piece currently identified under the newly replaced nozzle based on the visual recognition result of the visual recognition processing program (R s *W1, R s *H1), the upper computer program matches and compares the calibration piece size of the currently recognized calibration piece with the calibration piece information stored in the nozzle library, and determines whether the currently recognized calibration piece is the calibration piece of the corresponding model corresponding to the newly replaced nozzle. If it does not match, the next calibration piece is rescanned and identified. If it matches, the currently recognized calibration piece is determined to be the calibration piece of the corresponding model and the calibration piece is selected for automatic calibration.

[0068] In step S3, the newly replaced nozzle is moved to the top of the calibration station and the nozzle rod is controlled to rotate to zero. When the newly replaced nozzle is rotated to the zero position, the calibration plate is also rotated to the zero position at the same time. Then, the model of the calibration plate is selected according to the judgment result in the nozzle library.

[0069] The upper computer program controls the newly replaced nozzle to move to the top of the nozzle calibration station, selects the corresponding model of calibration piece, and turns on the gas switch of the nozzle calibration station. The main purpose of turning on the gas is to firmly adsorb the calibration piece on the plane to prevent the calibration piece from loosening or vibrating during the nozzle grasping process.

[0070] The head camera of the high-speed placement machine is controlled to move to above the corresponding calibration sheet, and the head camera is used to photograph the calibration sheet to obtain a first image.

[0071] Step S4: The host computer program calls the visual recognition processing program to automatically visually recognize the first image and obtain the current center coordinates (X c ,Y c), the upper computer program then controls the head camera to move in the X and Y directions respectively. During the movement, the upper computer program uses the visual recognition processing program to identify the center coordinates of the correction piece in real time and calculates the center deviation distance of the correction piece in the X and Y directions at the starting position. When the conditions of the X center deviation distance ≤ ± 0.5 mm and the Y center deviation distance ≤ ± 0.5 mm are met, the head camera stops moving and the current center coordinates of the correction piece (X c ,Y c );

[0072] The host computer program controls the head camera to move in the X and Y directions respectively, and during the movement, the deviation distances ΔX and ΔY of the center coordinates of the correction piece at the starting position are calculated in real time.

[0073] ΔX=(X c -W pix / 2)*R s , ΔY=(Y c -H pix / 2)*R s ,

[0074] When the calculated results are ΔX≦±0.5mm and ΔY≦±0.5mm, stop moving the head camera and record the current center coordinates (X c ,Y c ).

[0075] Step S5: The upper computer program controls the newly replaced suction nozzle to descend to the center of the calibration sheet and suck up the corresponding calibration sheet;

[0076] The upper computer program controls the newly replaced suction nozzle to automatically descend to the center of the corresponding calibration piece, and descend to a height where the bottom surface of the suction nozzle fully contacts the calibration piece. The vacuum generator of the suction nozzle is turned on to make the suction nozzle generate reverse airflow and suck up the calibration piece. Then the gas valve in the suction nozzle calibration station is closed to release the calibration piece, completing the process of the suction nozzle grabbing the calibration piece.

[0077] Step S6: The upper computer program controls the newly replaced nozzle to move the calibration sheet to the high-definition camera of the high-speed placement machine and moves the calibration sheet to the top of the high-definition camera of the high-speed placement machine, and uses the high-definition camera to shoot the calibration sheet and obtain a second image.

[0078] The host computer program calls the visual recognition processing program again to perform visual recognition on the second image and identify the current center coordinates (X0, Y0) of the calibration piece being sucked. It then controls the nozzle rod to rotate intermittently and drives the newly replaced nozzle installed on the nozzle rod and the calibration piece sucked by the nozzle to rotate intermittently. Each rotation angle is 45°, until the total rotation angle is equal to or greater than 360°. After each rotation of 45°, the visual recognition processing program is used to identify the current center coordinates of the calibration piece. The host computer program records the data of the center coordinates of the 8 sets of calibration pieces obtained.

[0079] The movement speed of the mobile correction piece shall not be greater than 0.1 times the movement speed of the high-speed placement machine during normal placement. If the movement speed of the mobile correction piece is too high, the correction piece may be offset, affecting the final correction result.

[0080] Step S7: The upper computer program controls the newly replaced suction nozzle to move to the top of the suction nozzle calibration station, controls the suction nozzle to move the calibration plate to the corresponding starting position of the calibration plate and releases it, puts the calibration plate back to the corresponding starting position, turns on the gas switch of the suction nozzle calibration station, and makes the calibration plate placed back to the starting position stably adsorbed in the suction nozzle calibration station.

[0081] The host computer program uses the head camera to shoot the calibration piece again, and calls the visual recognition processing program again to identify and obtain the current center coordinates (X c ’ ,Y c ’ ), and compare the center coordinates (X c ’ ,Y c ’ ) and the XY center deviation distance of the actual center coordinate, or compare the center coordinates (X c ,Y c ) and the center coordinates (X c ’ ,Y c ’ ), if the X center deviation distance ≤ ± 0.5 mm and the Y center deviation distance ≤ ± 0.5 mm, the recorded data is determined to be valid. Otherwise, re-execute steps 3 to 6 until the recorded data is determined to be valid data.

[0082] Specifically, identify and obtain the current center coordinates (X c ’ ,Y c ’ ), is to control the head camera to move along the X and Y directions respectively through the host computer program, and calculate the deviation distance ΔX of the current center coordinate of the correction piece put back to the starting position in real time during the movement ’and ΔY ’ ,

[0083] ΔX ’ =(X c ’ -W pix / 2)*R s , ΔY ’ =(Y c ’ -H pix / 2)*R s ,

[0084] Until the calculated result is ΔX ’ ≦±0.5mm and ΔY ’ When the head camera is less than ±0.5 mm, stop moving the camera and record the center coordinates (X c ’ ,Y c ’ ).

[0085] Step S8: The host computer program combines the interpolation formula and the 8 sets of valid data obtained by recording, takes the angle as the variable, and obtains an interpolation formula consisting of 8 sets of data for the newly replaced nozzle, which is recorded as the correction curve P of the rotation angle of the newly replaced nozzle and the nozzle X-direction deviation. x (θ) and the correction curve P of the rotation angle of the newly replaced nozzle and the deviation of the nozzle in the Y direction y (θ),

[0086] The correction curves in the X and Y directions are calculated using the Lagrange interpolation formula with the angle θ as the variable.

[0087]

[0088] Calculate 8 sets of valid data i (θ), we can get,

[0089]

[0090] Substitute the correction curves in the X and Y directions to construct the nozzle correction curve.

[0091]

[0092] The nozzle calibration curve is saved in the host computer program, and the automatic calibration of the newly replaced nozzle is automatically completed;

[0093] Step S9: Automatic compensation calibration without stopping the machine.

[0094] After completing step S8, the host computer program automatically switches to the placement working state. In the placement working state, the host computer program automatically compensates and calibrates the newly replaced nozzle in real time according to the nozzle calibration curve.

[0095] For the target position (X, Y), the actual position after the correction and compensation of the instruction with a rotation angle of β (target position XP x (β), target position YP y (β)).

[0096] The upper computer program compensates the target position (X, Y) of the newly replaced nozzle for the deviation of the correction curve in the X direction and the correction curve in the Y direction and calculates the actual position of the newly replaced nozzle. When the newly replaced nozzle rotates the corresponding angle β and reaches the target position, the upper computer program calculates the actual position of the newly replaced nozzle (target position XP x (β), target position YP y (β)), control the newly replaced nozzle to move to the calculated actual position (target position XP x (β), target position YP y (β)).

[0097] For replacing multiple nozzles at one time, each nozzle is automatically calibrated in turn according to steps S3 to S8, and the corresponding nozzle correction curve is constructed respectively, and then step S9 is automatically executed. During the mounting process, the upper computer program automatically compensates and calibrates the currently moving nozzle in real time in combination with the corresponding nozzle correction curve.

[0098] In the prior art, a high-speed placement machine performs a visual automatic correction on the concentricity of a newly replaced nozzle each time a new nozzle is replaced, so as to solve the problem of reduced overall placement accuracy due to an error in the center of the nozzle.

[0099] The present invention takes advantage of the mutual verification of the dual vision systems, and determines the deviation of the nozzle center by detecting the position change of the nozzle when it picks up the calibration piece under visual recognition. The deviations at all angles are fitted into a regression curve, namely the nozzle correction curve, for real-time adjustment of the deviation position during actual placement by the SMT high-speed placement machine, thereby reducing the risk of accuracy changes after replacing the nozzle.

[0100] 1. Perform the nozzle calibration procedure after the nozzle is replaced to reduce the mechanical error introduced by the nozzle replacement step and verify the accuracy of the nozzle replacement station.

[0101] 2. The accuracy of each nozzle will have some deviations due to usage and process manufacturing procedures. After replacing a new nozzle at the nozzle exchange station, a nozzle error correction is performed to effectively avoid the problem of inconsistent concentricity between nozzles and reduce the time cost of manual inspection in subsequent steps.

[0102] 3. After calculating the data deviation for each angle, the accuracy of the data sampling is further verified through multiple steps. The Lagrange interpolation method can more accurately obtain the actual situation of the deviation corresponding to each angle, with a higher degree of restoration than other fitting curves.

[0103] 4. The present invention is suitable for situations where a high-speed placement machine replaces a nozzle during the placement process. After the nozzle is replaced, the high-speed placement machine automatically corrects the newly replaced nozzle without stopping the machine. There is no need for operator intervention or manual operation. There is no need to stop the machine during the high-speed placement. After the nozzle correction is completed, it automatically switches to the original working state and continues the original placement work. The correction process is fully automated, simple, convenient and fast, with a high correction speed, thereby improving the effectiveness efficiency.

Claims

1. A method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine, characterized in that: A nozzle calibration station is added next to the nozzle exchange station of the high-speed placement machine. The nozzle calibration station is equipped with a calibration sheet placed in the starting position. After the upper computer program detects that the nozzle exchange station has completed the nozzle replacement action, the upper computer program automatically calibrates the newly replaced nozzle through the calibration function without stopping the machine, automatically switches to the placement working state, and automatically compensates and calibrates the newly replaced nozzle in real time, including the following steps: Select the calibration sheet pickup step, select the corresponding calibration sheet at the nozzle calibration station, move the nozzle to the top of the nozzle calibration station, and move the nozzle until the XY center deviation between the center of the newly replaced nozzle and the center of the currently selected calibration sheet at the starting position is ≤±0.5mm. The newly replaced nozzle descends and picks up the selected calibration sheet. Data recording step: The host computer program controls the suction nozzle that picks up the calibration sheet to move to the high-definition camera, calls the visual recognition processing program to identify the current center coordinates (X0, Y0) of the calibration sheet, and intermittently rotates the calibration sheet, each rotation angle is 45°, until the total rotation angle is equal to or greater than 360°. After each rotation of 45°, the visual recognition processing program is used to identify the current center coordinates of the calibration sheet. The host computer program records the data of the center coordinates of the eight sets of calibration sheets obtained; Verification step: Control the newly replaced suction nozzle to put the calibration piece back to the corresponding starting position, call the visual recognition processing program again to identify the center coordinates of the calibration piece, compare the XY center deviation distances of the front and rear center coordinates of the calibration piece, and if the X center deviation distance is ≤ ±0.5mm and the Y center deviation distance is ≤ ±0.5mm, the recorded data is determined to be valid. Otherwise, the calibration piece selection, data recording and verification steps are repeated until the recorded data is determined to be valid. 8 sets of valid data of the calibration piece center coordinates are recorded. Establish a correction curve step, establish an interpolation formula with angle as variable composed of 8 sets of valid data for the newly replaced nozzle, and construct a correction curve P of the rotation angle of the newly replaced nozzle and the nozzle X direction deviation x (θ) and the correction curve P of the rotation angle of the newly replaced nozzle and the deviation of the nozzle in the Y direction y (θ), the nozzle correction curve is constructed. The nozzle calibration curve is saved in the host computer program, and the automatic calibration process of the newly replaced nozzle is automatically completed; The automatic calibration step is carried out without stopping the machine. After completing the automatic calibration process, the upper computer program automatically switches to the placement working state. In the placement working state, the upper computer program automatically compensates and calibrates the newly replaced nozzle in real time according to the nozzle calibration curve. For the target position (X, Y), the actual position after the correction and compensation of the instruction with a rotation angle of β (target position XP x (β), target position YP y (β)).

2. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 1, characterized in that: The following steps are included: Step S1: The nozzle calibration station is provided with a black calibration plate as a background. The calibration plate is a white ceramic calibration plate. Arranged on the calibration plate are multiple ceramic calibration plates of different models and sizes for detecting nozzles of different length and width sizes. The length and width sizes of the ceramic calibration plates include but are not limited to 1x1mm, 2x2mm, 3x3mm, 4x4mm, and 5x5mm. Each ceramic calibration plate is placed at the corresponding starting position. Step S2: After the host computer program of the high-speed placement machine detects that the nozzle exchange station has completed the nozzle replacement action, the host computer program automatically executes steps S3 to S8 once through the correction function, automatically calibrates the newly replaced nozzle without stopping the machine, automatically switches to the placement working state after the automatic correction process is completed, and automatically executes step S9 during the automatic placement working process, automatically calibrating the newly replaced nozzle in real time; Step S3: The upper computer program controls the newly replaced nozzle to move to the top of the nozzle calibration station and selects the calibration piece with the actual center coordinate of the corresponding model; Step S4: Align the center of the newly replaced nozzle with the center of the currently selected calibration piece at the starting position and the XY center deviation distance is ≤ ±0.5mm. The implementation steps are as follows: controlling the head camera of the high-speed placement machine to move to the top of the corresponding calibration plate, using the head camera to shoot the calibration plate and obtain a first image; the host computer program calls the visual recognition processing program to automatically visually recognize the first image and identify the current center coordinates (X c ,Y c ), The host computer program then controls the head camera to move in the X and Y directions, and compares the actual center coordinates with the recognized center coordinates (X c ,Y c ) in the center deviation distance in the XY direction, When the X center deviation distance is less than or equal to ±0.5mm and the Y center deviation distance is less than or equal to ±0.5mm, the head camera is stopped from moving and the current center coordinates (X c ,Y c ); Step S5: The upper computer program controls the newly replaced suction nozzle to descend and suck up the corresponding calibration piece; Step S6: The upper computer program controls the newly replaced suction nozzle that sucks the calibration sheet to move to the high-definition camera of the high-speed placement machine, and moves the calibration sheet to the top of the high-definition camera of the high-speed placement machine. Use a high-definition camera to shoot the calibration film and obtain a second image. The host computer program calls the visual recognition processing program again to perform visual recognition on the second image and identify the current center coordinates (X0, Y0) of the calibration film being sucked. Control the intermittent rotation of the nozzle rod and drive the newly replaced nozzle installed on the nozzle rod and the calibration piece sucked by the nozzle to rotate intermittently, with each rotation angle being 45° until the total rotation angle is equal to or greater than 360°. After each rotation of 45°, the current center coordinates of the calibration piece are respectively identified by the visual recognition processing program, and the upper computer program records the obtained data of the center coordinates of 8 sets of calibration pieces; Step S7: The upper computer program controls the newly replaced nozzle to move to the nozzle calibration station, controls the nozzle to move the calibration sheet to the corresponding starting position of the calibration sheet and releases it, and puts the calibration sheet back to the corresponding starting position. The host computer program uses the head camera to shoot the calibration piece again, and calls the visual recognition processing program again to identify and obtain the current center coordinates (X c ’ ,Y c ’ ), and compare the center coordinates (X c ’ ,Y c ’ ) and the XY center deviation distance of the actual center coordinate, or compare the center coordinates (X c ,Y c ) and the center coordinates (X c ’ ,Y c ’ )’s XY center deviation distance, If the X center deviation distance is less than or equal to ±0.5mm and the Y center deviation distance is less than or equal to ±0.5mm, the recorded data is determined to be valid. Otherwise, repeat steps 3 to 6 until the recorded data is determined to be valid. Step S8: The host computer program combines the interpolation formula and the 8 sets of valid data obtained by recording, takes the angle as the variable, and obtains an interpolation formula consisting of 8 sets of data for the newly replaced nozzle, which is recorded as the correction curve P of the rotation angle of the newly replaced nozzle and the nozzle X-direction deviation. x (θ) and the correction curve P of the rotation angle of the newly replaced nozzle and the deviation of the nozzle in the Y direction y (θ), the nozzle calibration curve is constructed, The nozzle calibration curve is saved in the host computer program, and the automatic calibration of the newly replaced nozzle is automatically completed; Step S9: Automatic compensation calibration without stopping the machine. After completing step S8, the host computer program automatically switches to the placement working state. In the placement working state, the host computer program automatically compensates and calibrates the newly replaced nozzle in real time according to the nozzle calibration curve. For the target position (X, Y), the actual position after the correction and compensation of the instruction with a rotation angle of β (target position XP x (β), target position YP y (β)).

3. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 2, characterized in that: In step S9, the host computer program performs deviation compensation on the target position (X, Y) of the newly replaced nozzle based on the correction curve in the X direction and the correction curve in the Y direction and calculates the actual position of the newly replaced nozzle. When the newly replaced nozzle rotates the corresponding angle β and reaches the target position, the host computer program calculates the actual position of the newly replaced nozzle (target position XP x (β), target position YP y (β)), control the newly replaced nozzle to move to the calculated actual position (target position XP x (β), target position YP y (β)).

4. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 2, characterized in that: In step S2, the host computer program automatically selects the corresponding model of the calibration film. The surface of each nozzle is provided with a dot matrix code representing the nozzle. After the upper computer program detects the nozzle replacement operation at the nozzle exchange station, the upper computer program uses any camera to capture the dot matrix code of the newly replaced nozzle, uploads the recognition result of the dot matrix code to the calibration function, and automatically determines and selects the corresponding model of the calibration film based on the nozzle information in the nozzle library and the corresponding matching calibration film information, and reads and obtains the actual center coordinates of the calibration film; In step S3, the newly replaced suction nozzle is moved to the top of the calibration station and then the suction nozzle rod is controlled to rotate to the zero point, so as to rotate the newly replaced suction nozzle to the zero position.

5. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 4, characterized in that: The step of automatically selecting the correction film, Set the pixel range of the head camera to (W pix ,H pix ), pixel accuracy is R s , set the length and width of the currently selected identification correction piece (W p ,H p ), The host computer program calculates the size of the calibration piece currently identified below the newly replaced nozzle based on the visual recognition result of the visual recognition processing program and is (R s *W1, R s *H1), The upper computer program matches and compares the calibration piece size of the currently identified calibration piece with the calibration piece information stored in the nozzle library, and determines whether the currently identified calibration piece is the calibration piece of the corresponding model corresponding to the newly replaced nozzle. If it does not match, the next calibration piece is rescanned and identified. If it matches, the currently identified calibration piece is determined to be the calibration piece of the corresponding model and the calibration piece is selected for automatic correction.

6. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 5, characterized in that: In step S4, the host computer program controls the head camera to move in the X and Y directions respectively, and calculates the deviation distances ΔX and ΔY of the center coordinates of the calibration plate at the starting position in real time during the movement. ΔX=(X c -W pix / 2)*R s ,ΔY=(Y c -H pix / 2)*R s , When the calculated results are ΔX≦±0.5mm and ΔY≦±0.5mm, stop moving the head camera and record the current center coordinates (X c ,Y c ); In step S7, the host computer program controls the head camera to move in the X and Y directions respectively, and calculates the deviation distance ΔX of the current center coordinate of the correction piece put back to the starting position in real time during the movement. ’ and ΔY ’ , ΔX ’ =(X c ’ -W pix / 2)*R s ,ΔY ’ =(Y c ’ -H pix / 2)*R s , Until the calculated result is ΔX ’ ≦±0.5mm and ΔY ’ When the head camera is less than ±0.5 mm, stop moving the camera and record the center coordinates (X c ’ ,Y c ’ ).

7. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 1, characterized in that: The movement speed of the correction plate is no more than 0.1 times the movement speed of the high-speed placement machine during normal placement.

8. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 1, characterized in that: Step S8: The correction curves in the X and Y directions are calculated using the Lagrange interpolation formula with the angle θ as the variable. Calculate 8 sets of valid data i (θ), we can get, Substituting the correction curves in the X and Y directions, the nozzle correction curve is constructed.

9. The method for automatically calibrating a nozzle of a high-speed placement machine without stopping the machine according to claim 1, characterized in that: When replacing a plurality of the suction nozzles at one time, each suction nozzle is automatically calibrated in turn and a corresponding suction nozzle calibration curve is constructed.

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