JP2005079358A - Component mounting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a component mounting apparatus capable of preventing a detected load value of a load cell from being influenced by an influence of a piping cable and of hereby improving the accuracy of load control. <P>SOLUTION: The component mounting apparatus 20 consists of a first movable part 22 including a load cell 2 driven vertically with a directly movable actuator 1 and of a second movable part 23 suspended from the load cell 2 and including a mounting head 6 mounted thereon, and controls the pressing force of the mounting head 6 by feeding back a detected load of the load cell 2. In the apparatus, an intermediate part of a cable or the like connected to the second movable part 23 is held by a cable holding part 12 mounted on the first movable part 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a component mounting apparatus, and particularly includes a first movable part including a load cell and a second movable part to which a mounting head is attached, and controls a pressing force of the mounting head by feeding back a detected load of the load cell. It is related with what made it possible to improve the accuracy of load control in the case of doing so.

As a conventional component mounting apparatus of this type, a force is preliminarily applied to the bonding tool by an air cylinder so that the load detection value by the load cell decreases when the component is pressed (see, for example, Patent Document 1), The load pressure when the bare chip is placed on the substrate is detected by a load cell, the detected value is compared with a reference pressure, a trigger signal is output, and the vertical movement of the suction nozzle unit is controlled (for example, Patent Document 2).
JP-A-9-064119 JP-A-8-330790

In the conventional component mounting apparatus described above, there is a concern that the load value detected by the load cell is affected by the influence of the piping cable connected to the bonding tool or the suction nozzle, which may hinder the improvement of load control accuracy. The

The present invention has been made in view of the above-described conventional situation, and provides a component mounting apparatus that can prevent the detection load value of a load cell from being affected by the influence of a piping cable and can improve the accuracy of load control. Is an issue.

According to a first aspect of the present invention, the load cell includes a first movable portion including a load cell driven in the vertical direction by a direct acting actuator, and a second movable portion suspended from the load cell and having a mounting head attached thereto. In the component mounting apparatus configured to feed back the detected load and control the pressing force of the mounting head, the middle part of the cables connected to the second movable part is attached to the first movable part. It is characterized by being held by the cable holder.

According to a second aspect of the present invention, in the first aspect, when the detected load of the load cell is fed back to control the pressing force of the mounting head, the detected load of the load cell and the pressing load applied to the component by the mounting head A correction unit is provided that corrects the load detected by the load cell or the target pressing load applied to the component by the mounting head based on correction data acquired from the difference.

The invention of claim 3 is the piping tube for supplying fluid or fluid pressure to the mounting head among the cables connected to the second movable part in claim 1 or 2, wherein the mounting head In the case where the state of the internal fluid changes during the mounting operation, there is a margin in length between the cable holding part attached to the first movable part and the connection to the second movable part. It is characterized in that at least one bent portion is provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects, among the cables connected to the second movable portion, the material of the piping tube that supplies fluid or fluid pressure to the mounting head is rubber. It is characterized by being.

According to the first aspect of the present invention, since the intermediate portion of the cables connected to the second movable portion is held by the cable holding portion attached to the first movable portion, the workpiece (component) and the mounted substrate are When not in contact, the static detected load of the load cell does not change depending on the positions of the first and second movable parts. Therefore, contact detection by load cell load is easy and reliable, and accurate load control can be performed regardless of the contact position between the workpiece and the substrate to be mounted.

According to the second aspect of the present invention, when the detected load of the load cell is fed back and the pressing force of the mounting head is controlled, the correction data acquired in advance is taken into account, so that accurate load control is performed. be able to. For example, due to deformation of the load cell during load control or deformation of the cable holding part caused by the force received from the cables located on the opposite side of the second movable part across the cable holding part, the second movable part across the cable holding part Even if the cables located on the side are deformed and the load detected by the load cell fluctuates, the load fluctuation due to these effects is reproducible both in principle and experimentally, and is acquired as correction data in advance. It is possible to perform accurate load control by taking this correction data into consideration.

According to a third aspect of the present invention, there is provided a piping tube for supplying fluid or fluid pressure to the mounting head, wherein the state of the internal fluid changes during the mounting operation of the mounting head. Since the bent portion is provided between the cable holding portion attached to the movable portion and the connection point to the second movable portion, the force transmitted to the second movable portion due to the change in the state of the internal fluid (hereinafter, The influence of the relative transmission force) can be absorbed by the bent portion, and precise positioning and precise load control can be continued.

According to the invention of claim 4, among the cables connected to the second movable part, the material of the piping tube that supplies fluid or fluid pressure to the mounting head is made of rubber. By connecting to the movable part, it is possible to absorb the influence caused by the force (hereinafter referred to as absolute transmission force) received by the second movable part, and it is possible to continue precise positioning and precise load control. That is, in the case of a tube made of silicone rubber or the like, if it is bent to some extent, even if it is further bent, the absolute transmission force hardly changes, so even if the correction data according to claim 2 is not taken into consideration. The load can be controlled with high accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a front view schematically showing a component mounting apparatus according to an embodiment of the present invention. In the figure, in the component mounting apparatus 20 of the present embodiment, the voice coil motor 1 is disposed as a linear motion actuator comprising a yoke 1A and a bobbin 1B on a support arm portion 21a of a frame 21 fixed to an installation surface or the like. . A load feedback load cell 2 is connected to the bobbin 1 </ b> B of the voice coil motor 1, and these constitute a first movable portion 22. The first movable portion 22 is guided in the vertical direction by the linear guide 3 and is urged by the retracting spring 4 to return upward.

Further, the load feedback load cell 2 suspends a second movable part 23 provided with the scale 5B of the linear scale 5 and the mounting heater tool 6, and the second movable part 23 is a static pressure gas without friction. Guided by the bearing 7. Reference numeral 5A denotes a measurement head fixed to the frame 21 side. The static pressure gas bearing 7 includes a bearing pad 7B fixed to the frame 21 side and a movable shaft 7A supported by the bearing pad 7B so as to be movable up and down. The scale 5B and the mounting heater tool 6 are connected.

Since the second movable part 23 is guided by the static pressure gas bearing 7 having no friction as described above, the load feedback load cell 2 that lifts the second movable part 23 is adsorbed by the attachment 8 at the tip of the mounting heater tool 6. Further, the force that the workpiece (component) 9 receives from the mounted substrate 10 can be accurately detected, and therefore, the pressing force generated between the workpiece 9 and the mounted substrate 10 can be accurately detected. .

A controller (not shown) to which the detected load value is input can realize an arbitrary pressing force by controlling a current flowing through the voice coil motor 1. Further, since the position of the second movable portion 23 is held by the static pressure gas bearing 7, it can slide with high accuracy in the vertical direction (Z-axis direction) and during mounting. The position can be accurately held.

Here, the heater tool 6 is connected with cables 11 including a number of cables such as an attachment suction air tube, a workpiece suction air tube, a cooling air tube, a nitrogen purge tube, a power line, and a thermocouple wire. . Conventionally, precise contact detection and load control have been difficult due to the force generated by these cables 11.

Therefore, in the present embodiment, since the cable holding portion 12 is provided in the first movable portion 22 and the cables 11 are held by the cable holding portion 12, the conventional problems can be solved. That is, the first movable portion 22 and the second movable portion 23 move up and down substantially without changing the distance from each other, and therefore the cable holding portion 12 of the first movable portion 22 to the cable of the second movable portion 23. The shape of the cable reaching the holding portion 14 is not substantially changed by the vertical movement of the first and second movable portions 22 and 23. Therefore, the load applied to the load feedback load cell 2 by the cables 11 does not substantially change during operation. Therefore, the load feedback load cell 2 is not affected by the force of the cables 11 and the work 9 and the load. The pressing force generated between the mounting substrates 10 can be detected almost accurately.

Therefore, the component mounting apparatus 20 of the present embodiment accurately detects a load change due to the contact between the work 9 and the mounted substrate 10 when the first and second movable parts 22 and 23 are lowered by position control. It can be determined that the workpiece 9 and the mounted substrate 10 are in contact with each other. The movable parts 22 and 23 descend at a high speed at first, but descend at a low speed when approaching the contact position. Since the contact is made at a low speed, there is no fear of applying an impact load to the workpiece 9 or the mounted substrate 10 at the time of contact, and contact detection is not hindered by the load fluctuation due to the inertial force of the second movable portion 23. Even after switching to load control after contact detection, the detected load is hardly affected by stress relaxation of the cables 11, and an arbitrary pressing force can be realized accurately.

Thus, in this embodiment apparatus 20, since the load detected by the load cell 2 does not change depending on the position of the movable part in the vertical (Z-axis) direction, the load value of the load cell 2 before starting to descend is also the load cell 2 at the position immediately before contact. There is also almost no difference in the load value. Accordingly, it is not necessary to record the load detection value immediately before the contact in the vicinity of the contact position and subtract from the load detection value during the pressing operation, and the height of the stage 15 on which the substrate 10 is mounted is high. In addition, there is no influence on the load value due to the change in the contact height due to the difference between the workpiece 9 and the mounted substrate 10.

More precisely, in actuality, the load feedback is influenced by the deformation of the load cell 2 during the load control or the deformation caused by the force that the cable holding portion 12 receives from the cables 11 ′ located above the load cell 12. The detected load of the load cell 2 is slightly affected. However, since this detected load fluctuation is reproducible both in principle and experimentally, as proposed in claim 2, it is obtained as correction data in a prior experiment, and correction is performed according to this correction data. Can be done. With this correction, the load feedback load cell 2 can accurately detect the pressing force generated between the workpiece 9 and the mounted substrate 10 at the same level as when the cable is present or not. Accordingly, the component mounting apparatus 20 can accurately realize an arbitrary pressing force at the same level as when the cables 11 are not provided.

The acquisition of the correction data will be described.
In FIG. 1, an evaluation load cell is arranged in place of the stage 15 to actually measure the load applied to the part. This measured value is compared with the output value of the load cell 2 provided in the component mounting apparatus, and if there is a difference, a correction value is set based on the difference. At this time, the output value of the load cell 2 may be corrected so as to be equal to the load actually applied to the component, or the target set load may be corrected so that a desired load is applied to the component. If differences are measured at a plurality of points, correction values at other points can be estimated from the relationship between the differences.

For example, when the target set load is 100 gf (the output value of the load cell 2 is 100 gf) and the output (measured load) of the evaluation load cell is 102 gf, the correction data is +2 gf, and this is the output value of the load cell 2 Application is detected as 102 gf when the output value is corrected. On the other hand, when the target set load is corrected, the correction data is −2 gf, and this is applied to the target set load to be 98 gf. In either case, the same effect can be obtained.

The error to be corrected in claim 2 is very small, and load control with sufficiently high accuracy can be achieved with the configuration of claim 1 alone. However, with the configuration of claim 2, load control with higher accuracy can be achieved. Here, the internal pressure and flow rate of the piping cables connected to the heater tool 6 change during the component mounting operation, which affects load control. That is, for example, load control may be affected by ON / OFF of cooling air, ON / OFF of nitrogen purge, and ON / OFF operation of vacuum suction accompanying the end of workpiece gripping. Therefore, as proposed in claim 3, between the cable holding part 12 attached to the first movable part 22 and the cable holding part 14 provided in the second movable part 23 of the cables 11. It is preferable to provide a bent portion 11a having a deflection D of, for example, 5 to 6 times the cable diameter. By doing in this way, the influence of the force that the internal fluid exerts on the second movable part with the ON / OFF operation of the air can be offset by the force generated in the structure of the cables itself. The force due to the internal fluid of the cables does not act on the second movable part 23.

Moreover, the 2nd movable part 23 receives force by the influence of the connected cables 11 itself. This force is defined as absolute transmission force. On the other hand, the force transmitted to the second movable part changes with a change in the state of the internal fluid, such as a change in supply flow rate or ON / OFF of pressure supply. This change is defined as relative transmission force.

The relative transmission force generated with the change in the state of the internal fluid becomes an obstacle to load control. However, the relative transmission force can be eliminated by performing the piping connection as described above. Therefore, even when the second movable part is required to perform precise positioning and precise load control, the precise positioning and precise load control can be continued without being affected by the state change of the fluid in the pipe. This is due to the following reason.

(A) “Change in momentum per unit time given to the second movable part by the internal fluid (given by the fluid pressure) with changes in the state of the internal fluid, such as changes in the supply flow rate or pressure supply ON / OFF The momentum of the fluid flowing into the second movable part) ”changes, but at the same time, a stress change occurs in the tube cross section, and (b)“ the stress on the tube cross section gives the second movable part The power that can be changed. The change in (a) and the change in (b) are substantially equal in magnitude and opposite in direction, so they cancel each other. Therefore, the force transmitted to the second movable part does not change as a whole with the change in the state of the internal fluid.

The change in the force acting on the tube cross-section due to the change in the internal fluid state appears almost as a change in the axial force, and almost no shear force change occurs. , (A) and (b) can be shown to need to be offset.

When the first movable part and the second movable part move up and down substantially without changing the distance as in the embodiment of the present invention, it is not felt at first glance that the tube needs to be bent. However, as described in the third aspect of the present invention, it is possible to obtain the effect that the precise positioning and the precise load control can be continued without being affected by the change in the state of the fluid inside the pipe by being bent and bent. .

The piping tube of the cables 11 is preferably made of a soft material such as silicone rubber. The reason is that if a rigid tube is bent and connected, the absolute transmission force becomes extremely large. It is desirable that the absolute transmission force is not present if possible, and a rigid tube should not be used. Further, in the case of a highly rigid tube, the absolute transmission force greatly changes with respect to a minute position change. For example, in FIG. 1, the distance between the cable holding part 12 of the first movable part and the cable holding part 14 of the second movable part slightly changes due to the change in strain of the load cell 2 accompanying the fluctuation of the pressing force. For a minute change, the rigid transmission tube has a considerably large change in absolute transmission force. Therefore, even if the relative transmission force due to ON / OFF of the air can be eliminated, the change of the absolute transmission force with respect to the deformation becomes large, and even if the correction according to the method of claim 2 is performed, the error becomes large. End up. In the case of a tube made of silicone rubber, if it is bent to some extent, even if it is bent further, the absolute transmission force hardly changes, so even if correction is not performed by the method according to claim 2, it is high. Load control can be performed with accuracy. In the case of a plastic tube, there is a phenomenon such as stress relaxation peculiar to a viscoelastic body, which is difficult to handle when considering load control. From this point, it is better to use a soft rubber tube.

It is a front view which shows typically the component mounting apparatus by one Embodiment of this invention.

Explanation of symbols

1 Voice coil motor (direct acting actuator)
2 Load cell 6 Mounting head (Heater tool for mounting)
DESCRIPTION OF SYMBOLS 11 Cable 12 Cable holding part 11a Bending part 20 Component mounting apparatus 22 1st movable part 23 2nd movable part

Claims (4)

A first movable part including a load cell driven in the vertical direction by a linear actuator, and a second movable part suspended from the load cell and attached with a mounting head, and feeding back the detected load of the load cell In the component mounting apparatus configured to control the pressing force of the mounting head, the middle part of the cables connected to the second movable part is held by the cable holding part attached to the first movable part. A component mounting device characterized by The correction data acquired from the difference between the load detected by the load cell and the pressure applied to the component by the mounting head when the load detected by the load cell is fed back to control the pressing force of the mounting head. And a correction unit that corrects a load detected by the load cell or a target pressing load applied to the component by the mounting head. In Claim 1 or 2, it is a piping tube which supplies fluid or fluid pressure to the mounting head among the cables connected to the second movable part, and during the mounting operation of the mounting head, The fluid whose state changes is that at least one bend with a margin in length between the cable holding part attached to the first movable part and the connection to the second movable part. A component mounting apparatus comprising a part. 4. The pipe tube for supplying a fluid or fluid pressure to the mounting head among the cables connected to the second movable part according to claim 1, wherein the material of the piping tube is rubber. Component mounting device.

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