JP5872827B2 - Component mounting equipment - Google Patents

Description

  The present invention relates to a component mounting apparatus (chip mounter) for mounting components on a substrate.

  A component mounting apparatus (hereinafter referred to as a chip mounter) includes a mechanism (hereinafter referred to as a mount mechanism) for lowering a nozzle holding an electronic component (hereinafter referred to as a chip), a moving body that supports the mechanism, and a beam that serves as a driving stage for the moving body. And a platform that serves as a beam driving stage. The chip mounter moves the mount mechanism to a predetermined position on the substrate with the drive stage, and after the operation of the drive stage is completed, the nozzle is lowered by the operation of the mount mechanism, and the chip is mounted on the substrate placed on the mount It is. Such a chip mounter is required to increase the speed of the chip mounting cycle and to increase the accuracy of the mounting position.

  In Patent Documents 1 and 2, notch filter processing including moving average processing such as S-shaped drive control is performed so that the component corresponding to the target natural frequency is zeroed as much as possible by Fourier transforming the command signal of the actuator. The technique which produces | generates a command signal by giving, and the technique of making a residual vibration small using some vibration observer etc. are disclosed.

  In Patent Document 3, the response time of the acceleration command and the deceleration command of the command signal of the controller of the actuator is set to a reciprocal of the natural frequency of interest, or 25% or less of the reciprocal of the natural frequency. A method is disclosed.

JP-A-11-892891 JP 2002-318609 A JP 2009-181395 A

  Although not intended to limit the present invention, Patent Documents 1-3 will be described.

  In the techniques disclosed in Patent Documents 1 and 2, a component corresponding to a target natural frequency is subjected to notch filter processing including moving average processing such as S-shaped drive control. In these controls, although the residual vibration due to the natural frequency is reduced, an operation delay occurs with respect to the output time of the command signal, which causes a shift or delay in the next operation and hinders the speedup of the chip mounting cycle. It can be a factor. In addition, when vibration suppression control is performed by newly adding a vibration observer or the like to a moving body and a beam, it is difficult to reduce the size and space of the apparatus, which leads to an increase in cost.

  In Patent Documents 2 and 3, a technique for reducing the residual vibration by a method in which the output time of the response of the acceleration command and the deceleration command is set to the reciprocal of the natural frequency of the device structure or a method of setting the reciprocal frequency to 25% or less Is published. However, the residual vibration of an apparatus having a drive stage such as a chip mounter is caused by two types of natural vibrations such as the natural vibration of the mount mechanism and the entire apparatus. There is no single kind of natural vibration. In the chip mounter, the residual vibration generated in the mount mechanism is in a state in which the residual vibration caused by the natural vibrations of the mount mechanism and the entire apparatus are superposed at a certain rate. Further, depending on the operating distance of the drive stage, there are cases where the residual vibration caused by the natural vibration of the mount mechanism becomes the main factor, and residual vibration caused by the natural vibration of the entire apparatus becomes the main factor. Therefore, even if only the residual vibration caused by the same natural vibration is taken regardless of the operating distance as in Patent Documents 2 and 3, there is a difference in the effect of reducing the residual vibration. The position shift may not be reduced.

  The chip mounter uses different chip mounting intervals depending on the target component and substrate size, and the same chip is mounted on the substrate at a fixed interval, so the operating distance of the drive stage used for the chip mounter is short. It can be long or long. Therefore, it is necessary to reduce the residual vibration of the mount mechanism at any operating distance and increase the accuracy of the chip mounting position. In the prior art, no consideration has been given to this point.

  While not intending to limit the invention, the features of the invention will be described.

  The present invention substantially suppresses the influence of residual vibration in each of at least two operation modes, such as an operation mode in which the influence of residual vibration of the entire apparatus is dominant and an operation mode in which the influence of residual vibration of the mount mechanism is dominant. It is.

  In the present invention, the natural vibration period of the mount mechanism is set to be smaller than the natural vibration period of the entire apparatus, and the minimum value of the operation time of the actuator of the drive stage is set to be equal to twice the natural period of the mount mechanism.

  According to the present invention, the acceleration / deceleration operation time can be set even if the operation distance is increased under the condition that the operation time is twice or more of the natural vibration period of the mount mechanism and less than twice the natural vibration period of the entire apparatus. And the acceleration / deceleration operation time is made to coincide with the natural vibration period of the entire apparatus even when the operation distance is increased.

  In the present invention, the region in which the acceleration / deceleration time is switched from the natural vibration period of the mount mechanism to the natural vibration period of the entire apparatus is made into a combination of arbitrary waveforms such as a shape combining a plurality of step functions or ramp functions.

  According to the present invention, it is possible to improve the mounting accuracy of components compared to the related art.

1 is a front view of a schematic configuration of a chip mounter in Embodiment 1. FIG. 1 is a top view of a schematic configuration of a chip mounter in Embodiment 1. FIG. Drive stage command and vibration time history response diagram. FIG. 4 is a time history response diagram of commands and vibrations adjusted by the drive stage. FIG. 3 is a diagram for explaining control of the first embodiment. FIG. 6 is a diagram for explaining the control of the second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 are schematic configuration diagrams of the chip mounter according to the first embodiment. FIG. 1 is a front view and FIG. 2 is a top view. As shown in FIGS. 1 and 2, the chip mounter includes a gantry 32 on which a substrate 31 is disposed, a Y-axis drive stage moving means 33 that is provided on the gantry and supports the beam 16 and moves in the Y-axis direction, X-axis driving stage moving means 10 is provided on the beam 16 and supports the moving body 17 and moves in the X-axis direction.

  The Y-axis drive stage moving means 33 includes a pair of Y-axis guide rails 34 arranged in parallel to each other with a substrate sandwiched on a gantry, and a beam support that slides along the guide rails and supports both ends of the beam. A slider 35 and a Y-axis actuator 36 for driving the beam support slider are provided.

  The X-axis drive stage moving means 10 has a beam 16 that is long enough to bridge between a pair of Y-axis guide rails, and a pair of beams provided on the beam 16 along the beam longitudinal direction. An X-axis guide rail 19, a slider slidable along the guide rail, a moving body 17 fixed to the slider, and an X-axis actuator 18 that drives the moving body are provided. The moving body 17 is mounted with a mount mechanism 37 for storing a nozzle for mounting the chip on the substrate.

  Linear motors are used for the X-axis actuator 18 and the Y-axis actuator 36, respectively. The X-axis drive stage moving unit 10 and the Y-axis drive stage moving unit 33 are controlled by command signals output from a control unit of the chip mounter. This control unit performs various operations and processes described later.

  The X-axis drive stage moving means 10 includes a first motor for counting signals from the linear motor stator and a first optical system to be described later along the longitudinal direction of the beam 16 (another expression is the stationary side). The scale 21 is arranged. On the other hand, the linear motor movable element and the first optical system are arranged on the moving body 17 (movable side as another expression) that moves relative to the beam. The first optical system has a first light emitting element and a first light receiving element.

  A second scale for counting signals from a second optical system, which will be described later, is disposed below the Y-axis drive stage moving unit 33. The beam 16 is provided with a second optical system. The second optical system has a second light emitting element and a second light receiving element.

  The position of the mount mechanism 37 in the X-axis direction of the moving body 17 can be recognized by the first scale 21 and the first optical system. In addition, the position of the mount mechanism 37 in the Y-axis direction by the second scale and the second optical system can be recognized. That is, the first scale and the first optical system are a first position recognition system for recognizing the position of the mount mechanism 37 in the X-axis direction, and the second scale and the second optical system are Y It can be expressed as a second position recognition system for recognizing the position of the mount mechanism 37 in the axial direction.

The first position recognition system recognizes the position of the mount mechanism 37 in the X-axis direction continuously in time. Therefore, the vibration of the moving body 17 in the X-axis direction (this can also be expressed as the vibration of the entire apparatus) and the vibration of the mount mechanism 37 can be obtained from the time history response at this position. The second position recognition system recognizes the position of the mount mechanism 37 in the Y-axis direction continuously in time. Therefore, the vibration of the moving body 17 and the vibration of the mount mechanism 37 in the Y-axis direction can be obtained from the time history response at this position. That is, the first and second position recognition systems in the present embodiment can be expressed as being vibration recognition systems at the same time. In this embodiment, Tn ₍₁₎ and Tn ₍₂₎ described later are obtained from the time history response at this position.

In the present embodiment, it is desirable that the first and second position recognition systems are arranged so as to obtain a vibration of H _high -H _low within the operating range of the mount mechanism 37. This is because the residual vibration at the nozzle tip of the mount mechanism 37 can be obtained more accurately.

  With the above-described configuration, in the chip mounter of the present embodiment, the X axis drive stage moving means 10 and the Y axis drive stage moving means 33 can be used to mount any mount plane 37 on the XY axis on the substrate. It can be moved to the upper position, and the chip can be mounted at a predetermined position on the substrate. The mount mechanism 37 is movable in a direction including the normal line of the substrate.

  As described above, the mount mechanism 37 is moved by the X-axis drive stage moving means 10 and the X-axis drive stage moving means 33. The mount mechanism 37 is moved by the vibration accompanying this movement. Some kind of vibration occurs.

  This vibration will be described.

  FIG. 3 shows the speed command response v of the actuator, the acceleration command response α corresponding to the first-order derivative, and the time of the forced vibration x generated in the mount mechanism 37 when the operation distance d during operation of the drive stage is 1 mm. An example of a time history response at t is shown.

  FIG. 3A shows the relationship between the time t and the operating distance d of the mount mechanism 37. FIG. 3A shows that the mount mechanism 37 has moved by the distance d1 at time s1, and then stopped at the position of the distance d1.

  FIG. 3B shows the relationship between the time t and the speed command response v in the case of FIG. In FIG. 3B, the mount mechanism 37 reaches the distance d1 through a stage of performing an acceleration operation, a stage of performing a constant speed operation, and a stage of performing a deceleration operation during a time T until reaching the distance d1. Will do.

  FIG. 3C shows the relationship between the time t and the acceleration command response α in the case of FIG. In FIG. 3C, the acceleration at the stage of performing the acceleration operation is a1, the acceleration at the stage of performing the constant speed stage is zero, and the acceleration −a1 at the stage of deceleration.

  FIG. 3D is a diagram for explaining the relationship between time t and vibration displacement Δx in the case of FIG. The mount mechanism 37 is forced to vibrate by inertial force excitation while the time-speed command is output (during time T). On the other hand, after the positioning of the drive stage is completed, that is, immediately after the output of the speed command signal is completed, residual vibration due to natural vibration occurs in the mount mechanism 37. This residual vibration affects the mounting accuracy when the mount mechanism 37 mounts a component on the board. Therefore, it is preferable to reduce the influence of this residual vibration.

  Next, a method for reducing the influence of this residual vibration will be described.

  Now, it is assumed that the mount mechanism 37 moves at a distance d2 at time T (FIG. 4A).

  The mount mechanism 37 reaches the distance d1 through a stage of performing an acceleration operation, a stage of performing a constant speed operation, and a stage of performing a deceleration operation during a time T until reaching the distance d2. FIG. 4 (b)).

  Here, for example, the natural vibration of the mount mechanism 37 is modeled by one mass point and one degree of freedom spring (hereinafter, one degree of freedom model). In this case, the natural frequency [Hz] is expressed by the theoretical formula of Formula (1). The natural frequency Fn [Hz] is the reciprocal of the natural vibration period Tn [sec], k is the spring stiffness of the one-degree-of-freedom model, m is the mass of the one-degree-of-freedom model, and ωn [rad / sec] is the natural angle. Represents the frequency.

Considering the acceleration command response of the drive stage as the excitation condition of the one-degree-of-freedom model by multiplying the acceleration by the mass of the mount mechanism 37, the theoretical solution x (t) of the vibration response with respect to time t of the one-degree-of-freedom model is (2) to (5) are obtained by superposition. In the equation, α represents acceleration [m / sec ² ], ζ represents a damping ratio, Ta represents acceleration time [sec], and Tc represents constant speed time [sec]. In such a one-degree-of-freedom model, when calculation is performed using these theoretical solutions, the residual vibration of the mount mechanism 37 is minimized when the acceleration / deceleration time Ta is matched with the natural vibration period Tn (FIG. 4C). be able to. That is, if the acceleration / deceleration time Ta is matched with the natural vibration period Tn, the influence of the residual vibration of the mount mechanism 37 can be reduced (FIG. 4D).

  Next, the residual vibration will be described in more detail.

  In the chip mounter, the driving stage is operated, and the acceleration operation is performed from the stopped state. Thereafter, a deceleration operation for stopping at a predetermined position on the substrate is performed. During the acceleration / deceleration operation, an inertial force corresponding to the product of its own mass and acceleration acts on the mount mechanism 37. The direction of action of the inertia force in the acceleration operation and the deceleration operation is opposite to each other. The mount mechanism 37 is subjected to forced vibration with the time required for the acceleration / deceleration operation as an excitation cycle. The mount mechanism 37 vibrates in the X-axis direction when the drive stage is operated in the X-axis direction, and vibrates in the Y-axis direction when operated in the Y-axis direction. Then, after the operation of the drive stage is completed and the positioning of the XY axes is completed, residual vibration due to the natural vibration of the mount mechanism 37 occurs.

  Further, due to the operation of the drive stage, not only residual vibration of the mount mechanism 37 but also residual vibration caused by natural vibration that vibrates so that the entire apparatus rotates rigidly around the center of gravity of the apparatus is generated. In the mount mechanism, residual vibration is generated in a state where both natural vibrations are superimposed. Since both residual vibrations cause a deviation in the positioning of the XY axes, it is an important issue to reduce the residual vibrations for the control of the drive stage. In addition, since the entire apparatus vibrates, the floor provided with the apparatus vibrates greatly, which leads to environmental vibration noise. Therefore, it is important to reduce the residual vibration.

  That is, the residual vibration is roughly divided into two types. One is residual vibration due to vibration of the mount mechanism 37, and the other is residual vibration due to vibration of the entire apparatus. The two residual vibrations are generated in the X-axis direction and the Y-axis direction, respectively.

  This will be described in more detail.

When the mount mechanism 37 is moved in the X-axis direction (this can also be expressed as the first mode), the acceleration / deceleration time Ta of the speed command is a natural vibration period in which the mount mechanism 37 vibrates in the X-axis direction. (Hereinafter referred to as Tn _(1X) ) or the natural vibration period (hereinafter referred to as Tn _(2X) ) in which the entire apparatus vibrates in the X-axis direction can reduce the residual vibration of the mount mechanism 37.

When the mount mechanism 37 is operated in the Y-axis direction (this can also be expressed as a second mode), the speed command acceleration / deceleration time Ta is inherent to the mount mechanism 37 vibrating in the Y-axis direction. If the vibration period (hereinafter, Tn _(1Y) ) or the natural vibration period in which the entire apparatus vibrates in the Y-axis direction (hereinafter, Tn _(2Y) ) is matched, the residual vibration of the mount mechanism 37 can be reduced ( In the following, when the X axis and the Y axis are not distinguished, the natural vibration periods are denoted as Tn ₍₁₎ and Tn ₍₂ ).

However, the residual vibration of the mount mechanism 37 is a superposition of the residual vibrations of the respective periods of Tn ₍₁₎ and Tn ₍₂₎ . In other words, if the acceleration / deceleration time Ta is adjusted to one natural vibration period regardless of the operating distance of the drive stage, the residual vibration due to the other natural vibration period cannot be reduced depending on the operating distance of the drive stage. Depending on the case, it is conceivable that the chip mounting deviation cannot be reduced.

Therefore, in the chip mounter of the present embodiment, first, attention is paid to the fact that the mass of the mount mechanism 37 is smaller than the mass of the entire apparatus. Second, the residual vibration of the mount mechanism 37 is expressed as a superposition of the residual vibrations of the respective periods of Tn ₍₁₎ and Tn ₍₂₎ . It was noted that the influence of residual vibration of the mount mechanism 37 may be dominant. Third, the chip mounter is dominated by the residual vibration of the entire device in coarse motions that move over a relatively large distance, and the residual vibration of the mount mechanism in fine motions that travel a smaller distance than the coarse motion. We focused on the fact that the influence is dominant.

More specifically, when the influence of the natural vibration period due to the mass ratio is calculated based on the one-degree-of-freedom model using Equation (1), Tn ₍₁₎ is calculated as Tn ₍₂ 1 changed from one quarter of 10 _min), towards Tn ₍₁₎ is focused in becoming always smaller than Tn _(2). In the present embodiment, by utilizing this fact, the target natural vibration period is selected according to the operating distance of the drive stage. In other words, in an operation mode in which the influence of the residual vibration of the entire apparatus is dominant, the acceleration / deceleration time is substantially matched with the natural vibration period of the entire apparatus, and the influence of the residual vibration of the mount mechanism 37 is reduced. In the dominant operation mode, the acceleration / deceleration time can be expressed as substantially matching the natural vibration period of the mount mechanism 37.

  This will be described more specifically with reference to FIG.

  FIG. 5A shows the relationship between the operating distance d [mm] of the drive stage and the acceleration / deceleration time Ta. FIG. 5B shows the relationship between the time width T [sec] of the speed command response and the acceleration / deceleration time Ta [sec].

In this embodiment, for example, the minimum value Tmin of T is set to twice Tn ₍₁₎ . Under a condition where T is twice or more than Tn ₍₁₎ and less than twice Tn _{(2) (} an operation mode in which the influence of the residual vibration of the mount mechanism 37 is dominant), the acceleration / deceleration time Ta of the speed command is set to Tn. Match ₍₁₎ .

Under the condition where T is twice or more than Tn _{(2) (} an operation mode in which the influence of residual vibration of the entire apparatus is dominant), the acceleration / deceleration time Ta of the speed command is made to coincide with Tn ₍₂₎ .

  In other words, in relation to the operating distance and the acceleration / deceleration time, this may be expressed as two sections having a constant acceleration / deceleration time regardless of the operating distance. It is desirable that the speed v and acceleration α of the actuator of the drive stage are set so as not to exceed the maximum speed vmax of equation (6) and the maximum acceleration αmax of equation (7) from the acceleration / deceleration time Ta. That is, it is desirable that the speed v is not more than the maximum speed vmax and the acceleration α is not more than the maximum acceleration αmax.

  In this embodiment, while the drive stage is operating at a constant speed, forced vibration does not occur as shown in the theoretical solution, so the constant speed operation time does not necessarily have to be zero.

  By doing so, the influence of the residual vibration in each of at least two operation modes such as the operation mode in which the influence of the residual vibration of the entire apparatus is dominant, the operation mode in which the influence of the residual vibration of the mount mechanism 37 is dominant, and the like are appropriately obtained. Can be suppressed.

  Note that how the acceleration / deceleration time Ta is set can be arbitrarily set by the operator, and can be operated using various input devices and output devices.

  In addition, as shown in FIG. 5A, this embodiment can be expressed as changing the acceleration / deceleration time Ta according to the operating distance. However, in this embodiment, the operating distance is relatively large. For example, a case where the mount mechanism 37 moves onto a component supply device for supplying components to the mount mechanism 37 (component supply operation) can be considered. Further, the operation distance may be relatively small when the mount mechanism 37 actually mounts a component on a substrate (component mounting operation). That is, this embodiment can be expressed as changing the acceleration / deceleration time according to the type of operation of the chip mounter as a different side from the above-described side. It can also be expressed that the type of residual vibration to be controlled is changed according to the type of operation of the chip mounter.

  As another expression, the present embodiment adjusts the time width of the acceleration / deceleration operation time according to the natural frequency of the mount mechanism 37, and the residual vibration of the mount mechanism even when the operation distance changes. It can also be expressed as reducing.

  In this embodiment, the type of residual vibration to be controlled in each of the X-axis direction and the Y-axis direction is changed.

In this embodiment, Tn ₍₁₎ and Tn ₍₂₎ may be measured by the first and second position recognition systems before the operation of mounting the component.

  In this embodiment, it is determined which residual vibration is currently dominant according to the result obtained by at least one of the first and second position recognition systems during the actual component mounting operation, and the acceleration / deceleration time described above. May be determined.

  Next, Example 2 will be described. In the second embodiment, parts different from the first embodiment will be mainly described.

  As described with reference to FIG. 5, the effects of residual vibration in each of at least two operation modes, such as the operation mode in which the influence of the residual vibration of the entire apparatus is dominant and the operation mode in which the influence of the residual vibration of the mount mechanism 37 is dominant, are appropriate. Can be suppressed. Here, if the performance of the actuator is sufficient with respect to the acceleration / deceleration time Ta, the ideal acceleration / deceleration time is ideal as shown in FIG. However, although the first embodiment is not denied, there may be a case where the set acceleration / deceleration time Ta cannot be followed depending on the performance of the actuator. In that case, as shown in FIG. 6B, a section in which the actuator cannot follow occurs. Thus, the present embodiment suppresses the influence of residual vibration even when the actuator cannot follow.

  This will be described more specifically. In the present embodiment, a section in which the actuator cannot follow is a combination of a step function and a ramp function as shown in FIG. In this way, even when the actuator cannot follow, the operation mode in which the influence of the residual vibration of the entire apparatus is dominant, the operation mode in which the influence of the residual vibration of the mount mechanism 37 is dominant, and the like in each of at least two operation modes. The influence of residual vibration can be suppressed as much as possible. It should be noted that the operator can arbitrarily set the waveform in the section that the actuator cannot follow, and can be operated using various input devices and output devices.

  The first and second embodiments have been described above. Although not intended to be limited, other effects of the first and second embodiments will be described.

  In the first and second embodiments, since the vibration of the entire apparatus can be reduced, there is an effect of improving environmental vibration noise, such as reduction of vibration of the floor provided with the apparatus.

  In the first and second embodiments, since notch filters including S-shaped drive control and moving average processing are not used, there is no operation delay with respect to the command signal.

  In the first and second embodiments, since the position recognition system also has the function of the vibration recognition system, it is not necessary to newly provide a position recognition system, and it is only necessary to adjust the time width of the command signal response, thus increasing the cost. This makes it possible to reduce the size of the apparatus and save space.

  Note that the present invention is not limited to this embodiment, and in each of at least two operation modes such as an operation mode in which the influence of the residual vibration of the entire apparatus is dominant and an operation mode in which the influence of the residual vibration of the mount mechanism 37 is dominant. What substantially suppresses the influence of residual vibration is within the scope of the idea of the present invention.

10 X-axis drive stage moving means 16 Beam 17 Moving body 18 X-axis actuator 19 X-axis guide rail 20 Slider 21 First scale

Claims (1)

In a component mounting device that mounts components on a board,
A component mounting unit for holding the component and mounting the component on the substrate;
A moving unit that moves the component mounting unit relative to the substrate;
A control unit that changes an acceleration / deceleration time of the component mounting unit between a first operation in which residual vibration of the component mounting apparatus is dominant and a second operation in which residual vibration of the component mounting unit is dominant; And the control unit causes the acceleration / deceleration time to coincide with the natural vibration period of the component mounting apparatus in the first operation, and the acceleration / deceleration in the second operation. A component mounting apparatus characterized in that time is matched with the natural vibration period of the component mounting unit ,
A first system for obtaining vibration in a first direction of the component mounting portion;
A second system for obtaining vibration in a second direction of the component mounting portion,
The control unit changes the acceleration / deceleration time using a result obtained by at least one of the first system and the second system,
The first system is a system for obtaining vibration in the first direction of the component mounting unit from a time history response of the position in the first direction of the component mounting unit.
The component mounting apparatus, wherein the second system is a system that obtains vibration in the second direction of the component mounting unit from a time history response of the position of the component mounting unit in the second direction.