JP2010082711A - Surface mounting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct breaking of a perpendicular relationship of an X beam generated by thermal deformation caused by heat generation of a Y axis motor movable element in a gantry robot adopting a linear motor. <P>SOLUTION: A surface mounting device includes a parallel driving type gantry robot which guides/moves the X beam 12 for guiding/moving a mounted head 10 in an X axis direction, along corresponding Y axis frames 14A, 14B in a Y axis direction by first and second Y axis motors 42A, 42B comprising the linear motors fixed to both end parts respectively. The surface mounting device further includes: a determination means for determining whether or not torque generated on at least one of the Y axis motors during stopping exceeds a previously set limit value when the X beam is stopped at an optional target position by the first and second Y axis motors; and a correction means 48 for correcting the position of the X beam in the Y axis direction such that the torque becomes minimum when it is determined the torque exceeds the limit value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides thermal deformation for a surface-mounted apparatus, particularly an orthogonal robot of a parallel drive system in which an X beam for moving a mounting head in the X direction is moved in the Y axis direction by Y axis motors fixed to both ends thereof. The present invention relates to a surface mounting apparatus that is suitable for use in correcting a deviation of an orthogonal relationship that is caused.

  In general, a surface mounting apparatus includes a mechanism for accurately mounting an electronic component on a positioned circuit board after adsorbing an electronic component with a mounting head moved in a horizontal direction by an orthogonal robot.

  As a configuration of such an orthogonal robot, a Y-axis motor for driving an X beam orthogonal to the Y axis frame is disposed only at one end of the X beam, and the other end is in a free state. It is known that there are two types, a cantilever system that performs this and a parallel drive system that arranges Y-axis motors at both ends of the X beam.

  In the latter orthogonal driving type orthogonal robot, Y-axis motors provided at both ends of the X beam are connected to each other on the linear scales (Y-axis) provided on the corresponding Y-axis frames. By controlling so that the positional relationship is always in the same state, the orthogonal relationship of the orthogonal robot is always kept constant.

  In such an orthogonal robot, the orthogonal relationship may be lost due to heat generation during operation. However, as disclosed in Patent Document 1, a load against thermal expansion is known as a countermeasure against thermal expansion of the conventional orthogonal robot. A technique for providing a mechanical release mechanism against fluctuation is known.

JP 2008-4858 A

  However, particularly in the case of a parallel drive type orthogonal robot employing a linear motor, the X beam fixing member for fixing to both ends of the X beam is provided with a linear motor movable element for operation in the Y-axis direction. Since the shaft motor mover generates heat during operation, it is directly transmitted to the X beam fixing member. As a result, the X beam fixing member and a linear scale reading sensor (hereinafter also referred to as a detector) attached to the X beam fixing member. The positional relationship between the X-beam fixing member and the X-beam fixing member changes. In addition, when the temperature rise of the X beam fixing member is different on the left and right, even if the linear scale itself maintains a certain positional relationship, the difference in the amount of thermal deformation generated between the X beam fixing member and the detector is small. Since the left and right are different, the orthogonal relationship of the X beams is broken.

  If the orthogonal relationship breaks in this way, the left and right Y-axis motors continue to apply excessive force to the mechanical assembly state of the X beam, so that the torque during movement is normal. It will change with respect to the case of the state, and not only will it adversely affect the damping settling at the time of stopping, but also will generate a certain torque during stopping, thus generating unnecessary power consumption It will be.

  The present invention has been made to solve the above-described conventional problems. In a parallel drive type orthogonal robot employing a linear motor, the orthogonality of X beams generated by thermal deformation caused by heat generated by a Y-axis motor mover is achieved. It is an object of the present invention to provide a surface mount device that can correct the disruption of the relationship.

  In the present invention, the X beam for guiding and moving the mounting head in the X-axis direction is moved in the Y-axis direction along the corresponding Y-axis frame by the first and second Y-axis motors composed of linear motors fixed to both ends thereof. Generated in at least one of the stopped Y-axis motors when the X-beam is stopped at an arbitrary target position by the first and second Y-axis motors Determining means for determining whether or not the torque being exceeded exceeds a preset limit value, and when it is determined that the torque exceeds the limit value, the torque is minimized. The present invention solves the above-described problems by providing correction means for correcting the position of the X beam in the Y-axis direction.

  In the present invention, after the correction means drives the Y-axis motor generating the torque exceeding the limit value by a certain amount in the direction opposite to the generated torque until the generated torque becomes the reverse direction again. Further, the generated torque may be minimized by driving the generated torque little by little until the generated torque is reversed.

  According to the present invention, when the X beam is stopped by moving it to the target position on the Y axis by the first and second Y axis motors at both ends thereof, when torque is generated during the stop, Since the position of the X beam on the Y axis is corrected by the corresponding Y axis motor so that the torque is minimized, it is caused by the heat generation of the fixing member to which the Y axis motor is attached during the production operation. Even if the orthogonal relationship is broken, it can be easily corrected, so that it is possible to prevent wasteful power consumption during stoppage.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing an outline of a parallel drive type orthogonal robot applied to a surface mounting apparatus according to an embodiment of the present invention.

  The orthogonal robot of the present embodiment is a surface mounting apparatus in which a mounting head 10 for mounting electronic components on a substrate is guided and moved in the X-axis direction, and the X beam 12 is guided and moved in the Y-axis direction. Y-axis frames 14A and 14B are provided opposite to the left and right.

  The X beam 12 is provided with a linear scale 16 that defines the position in the X-axis direction, and an X-axis stator 18 of a linear motor is disposed in the same direction, and the X-axis stator 18 and the mounting head 10 are arranged. An X-axis linear motor is constituted by the X-axis movable element 20 of the linear motor attached to the motor.

  A detector 22 that reads the linear scale 16 is attached to the mounting head 10 that is moved and positioned in the X-axis direction by the X-axis linear motor.

  On the other hand, the left and right Y-axis frames 14A and 14B are also provided with linear scales 24A and 24B for defining the position in the Y-axis direction, and Y-axis stators 26A and 26B of the linear motor are arranged in the same direction. Yes.

  Further, X beam fixing members 28A and 28B are fixed to the left and right ends of the mounting head 10, and Y-axis movers 30A and 30B of linear motors are attached to the fixing members 28A and 28B, respectively. The Y-axis linear motors (first and second Y-axis motors) are constituted by the Y-axis stators 26A and 26B corresponding to the axis movers 30A and 30B.

  The left and right X beam fixing members 28A and 28B have detectors 32A and 32B for reading the positions on the left and right linear scales 24A and 24B when the X beam 12 is moved in the Y axis direction by the left and right Y axis linear motors. Are attached to each.

  Further, Y-axis origin sensors 34A and 34B used for returning the origin of the X beam 12 are installed at the reference positions on the left and right Y-axis frames 14A and 14B. Although not shown, an X-axis origin sensor is also installed on the X beam 12.

  FIG. 2 is a block diagram showing an outline of the control system of the orthogonal robot of the present embodiment.

  As described above, the linear motors 40, 42A, and 42B including one stator in the X-axis direction, two stators in the Y-axis direction, and a corresponding movable element are used, and each linear motor is for operating each of them. Servo amplifiers 44, 46A and 46B are provided.

  Each servo amplifier controls the operating current for the linear motors 40, 42A, 42B based on the position information from the detectors 22, 32A, 32B of each axis, and establishes the mechanical origin based on the origin information from the origin sensor. To do.

  The three servo amplifiers 44, 46A and 46B are connected to the axis control board 48, and provide the current axis state including position information to the axis control board 48, and the axis control board. Positioning operation and home position return operation are performed based on the command from.

  The axis control board 48 monitors the state of the axis given from each servo amplifier, gives a positioning command to each servo amplifier, and performs management to keep the orthogonal state of the X beam 12 constant. Yes.

  That is, the axis control board 48 sets in advance the torque generated in at least one of the stopped Y-axis motors when the X beam is stopped at the target position by the first and second Y-axis motors. A determination means for determining whether or not a certain limit value is exceeded; and when it is determined that the torque exceeds the limit value, the position of the X beam in the Y-axis direction is set so that the torque is minimized. It also functions as correction means for correcting.

  The axis control board 48 is connected to a machine control board 50 that manages the surface mounting device, and provides the state of each connected servo amplifier to the machine control CPU. An operation command is given to each servo amplifier.

  Next, the operation of this embodiment will be described.

  First, as a home return operation, a Y-axis home return method for causing the X beam 12 to coincide with the Y-axis home sensors 34A and 34B will be described.

  When the axis control board 48 receives the Y-axis origin return command from the machine control board 50, it issues a movement command to the left and right Y-axis motors 42A and 42B simultaneously toward the origin sensors 34A and 34B. The left and right servo amplifiers 46A and 46B acquire the origin positions on the respective Y axes by detecting the dogs that are the target positions of the fixing members 28A and 28B by the Y axis origin sensors 34A and 34B provided respectively.

  The axis control board 48 stores the difference between the linear scale count values received from the Y-axis detectors 32A and 32B at the time of return to the origin, and thereafter, the left and right Y-axis are always maintained as offsets. The shaft motors 42A and 42B are controlled. The left and right origin sensors 34A and 34B are adjusted so that the positions of the left and right X beam fixing members 28A and 28B at the time of origin return coincide with the mechanical orthogonal state. The positional relationship on the left and right Y axes coincides with the mechanical orthogonal relationship, and therefore the torque generated in each of the Y axis motors 42A and 42B when the X beam 12 is stopped is almost zero.

  However, if the distance between the X beam 12 fixing position on the X beam fixing members 28A and 28B and the detectors 32A and 32B changes from left to right due to the heat generated by the Y axis movers 30A and 30B due to the axis moving operation, Position control on the left and right Y axes is performed in a state in which the normal orthogonal relationship is broken, and torque is generated in each Y axis motor despite the offset being maintained at the time of stoppage.

  Therefore, in this embodiment, after the return to origin, the torque generated by the left and right Y-axis motors when the shaft is stopped when moving to an arbitrary target position is monitored, and a torque (for example, a predetermined limit value or more) When the current value is generated, the positional relationship of the X beam 12 on the left and right Y axes is corrected so that the torque at the stop is minimized.

  Next, this correction method will be described with reference to the flowchart of FIG.

  Either one of the two ends of the X beam 12, here the left Y coordinate (position on the linear scale) is kept constant, while the other right Y axis motor is opposite to the direction in which the torque is generated. Until the torque is generated in the opposite direction to the current state, the predetermined amount is moved by a predetermined amount (steps 1 and 2), and the rough deviation amount with respect to the correct orthogonal state is grasped.

  If the direction of torque generation is reversed by this rough adjustment, this time, the generated torque (absolute value) is driven and moved one pulse at a time (slightly small amount) in the opposite direction so that the generated torque is minimized. The position where the torque generation direction is reversed is obtained (steps 3 and 4).

  The count values of the current left and right linear scales obtained in this way are stored, and thereafter, for example, the left and right linear scales are maintained so as to maintain the stored positional relationship (left and right offset values) until the next home position return operation is performed. Parallel drive control by the Y-axis motor is performed.

  Next, the execution timing of the correction process according to the present embodiment during production in which normal component mounting is performed will be described with reference to the flowchart of FIG.

  A substrate (not shown) is transported to the position of the XY robot shown in FIG. 1 (step 11), positioned and fixed, and then the substrate mark is recognized (step 12). It is determined whether or not correction is necessary by a subroutine based on the command (described later) (steps 13 and 14).

  If it is determined in step 14 that correction is necessary, the mounting operation is temporarily interrupted (step 15), the correction process of FIG. 3 is executed to correct the orthogonal relationship (step 16), and then the substrate mark is again displayed. The mounting operation is resumed from the interrupted step (step 18), and the above operation is repeated up to the final mounting point (step 19).

  Next, processing by the subroutine of Step 13 for determining whether or not correction processing is necessary in Step 14 will be described with reference to the flowchart of FIG.

  As the determination timing, the operation based on the axis movement command for the Y-axis motor for mounting one electronic component is completed (step 21) until the droop pulse of the left and right Y-axis motor becomes smaller than the specified reference value ( Step 23) When the next axis movement command is not received (Step 22), it is performed every time. Here, the accumulated pulse refers to a deviation between the number of pulses set corresponding to the target position and the actual number of pulses when the X beam 12 is positioned and stopped by the Y-axis motor.

  As a judgment method, the amount of torque generated in the left and right Y-axis motors is examined, and correction is necessary when either or both of the left and right Y-axis motors generate torque exceeding a preset limit value. (Steps 24 and 25).

  According to the embodiment described above in detail, the following effects can be obtained.

(1) By monitoring the torque generated when the Y-axis motor is stopped, it is detected that the orthogonal relationship of the orthogonal robot has broken due to temperature rise, and the X beam is output by the left and right Y-axis motors so that the torque is minimized. Since the positional relationship of 12 on the Y-axis is corrected, it is possible to minimize fluctuations in torque during operation and to prevent wasteful power consumption during stoppage.

(2) When the torque when the Y-axis motor stops during the mounting operation is monitored and the torque at the time of stopping exceeds a set limit value, By correcting the orthogonal relationship and re-recognizing the substrate mark, it is possible to minimize the occurrence of mounting displacement due to the collapse of the orthogonal relationship.

The schematic diagram which shows the outline | summary of the orthogonal robot with which the surface mounting apparatus of one Embodiment which concerns on this invention is equipped. Block diagram showing the outline of the control system of the orthogonal robot A flowchart showing a correction procedure according to this embodiment. A flowchart showing the execution timing of correction processing according to the present embodiment The flowchart which shows the procedure of determination whether to perform the correction process by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mounting head 12 ... X beam 14A, 14B ... Y-axis frame 16, 24A, 24B ... Linear scale 18 ... X-axis stator 20 ... X-axis movable element 22, 32A, 32B ... Detector 26A, 26B ... Y-axis stator 28A, 28B ... X beam fixing member 30A, 30B ... Y-axis mover 34A, 34B ... Y-axis origin sensor

Claims (2)

The X beam for guiding and moving the mounting head in the X-axis direction is guided and moved in the Y-axis direction along the corresponding Y-axis frame by the first and second Y-axis motors composed of linear motors fixed to both ends thereof, respectively. In surface mount equipment with parallel drive orthogonal robots,
When the X beam is stopped at an arbitrary target position by the first and second Y-axis motors, does the torque generated in at least one of the stopped Y-axis motors exceed a preset limit value? Determining means for determining whether or not;
A surface mounting comprising correction means for correcting the position of the X beam in the Y-axis direction so that the torque is minimized when it is determined that the torque exceeds a limit value. apparatus.   After the correcting means drives the Y-axis motor generating torque exceeding the limit value by a certain amount in the direction opposite to the generated torque until the generated torque is again reversed, the generated torque is further reversed. 2. The surface mount device according to claim 1, wherein the generated torque is minimized by being driven little by little until the direction is reached.

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