JP5121590B2 - Surface mount equipment - Google Patents

Description

  The present invention relates to a surface mounting apparatus, and more particularly to a surface mounting apparatus suitable for application to load control when a component such as an electronic component is mounted on a substrate.

  Usually, as shown in FIG. 1, the surface mounting apparatus 1 mounts an electronic component that is transported by a substrate transport path 2 extending in the left-right direction and supplied to the component supply unit 3 on a positioned substrate S. A mounting head 10 included in the head unit, and an X-axis moving mechanism 12 and a Y-axis moving mechanism 14 for moving the mounting head 10 in the X direction and the Y direction, respectively.

  The X-axis moving mechanism 12 moves the mounting head 10 provided with the suction nozzle 10 </ b> A for sucking parts in the X-axis direction, and the Y-axis moving mechanism 14 is integrated with the X-axis moving mechanism 12 to move the mounting head 10 to the Y-axis. Move in the direction. In addition, the mounting head 10 includes a Z-axis moving mechanism that moves the suction nozzle 10A up and down in the Z-axis direction, and a θ-axis rotation mechanism that rotates the suction nozzle 10A around the nozzle axis (suction axis). I have. A substrate recognition camera 16 that captures an image of a substrate mark formed on the substrate S is attached to the mounting head 10 via a support member. In addition, a component recognition camera 18 that images a component sucked by the suction nozzle 10 </ b> A from below is disposed on the side of the component supply unit 3.

  In the electronic component mounting apparatus as described above, an electronic component such as a chip is sucked and held by a suction nozzle included in a mounting head, and then mounted on a substrate such as a positioned printed board.

  In order to mount various electronic components on the substrate in this way, a plurality of component supply devices such as a tape feeder are provided in the component supply unit 3 so that the corresponding electronic components can be sucked and held by the suction nozzle. A method is adopted in which an electronic component is mounted on each pickup and an electronic component is supplied to each pickup position. Hereinafter, the mounting head, the suction nozzle, and the electronic component are also simply referred to as a head, a nozzle, and a component, respectively.

  In recent years, miniaturization of parts has progressed, and reduction of the load applied to the parts by the nozzle when adsorbed from a part supply apparatus or mounted on a board is required. On the other hand, it is required to control the load applied to the component by the nozzle when the flip chip fluxer (flux) is transferred or mounted on the substrate (the component is pressed by the nozzle for a certain time under a certain load). In addition, the market demands tact-up (increase in the number of parts mounted per hour), and there is a tendency to increase the number of nozzles to be mounted on the head. In addition, the head itself is one machine for tact-up purposes. There is also a tendency to increase the number of heads per head.

  As an example of load control technology applied to parts by nozzles, load sensors are placed on each nozzle, the load applied to the parts by the nozzles is measured for each nozzle, and the operation of the nozzle lifting mechanism (Z-axis) is controlled from the results. A method of controlling the load is disclosed in Patent Document 1.

  As another example of the load control technology that the nozzle gives to the component, a load sensor is arranged on the side supporting the substrate on which the component is mounted, and the load applied by the nozzle to the component is measured via the substrate. Discloses a method for controlling the load by controlling the operation of the nozzle lifting mechanism (Z-axis).

JP-A-2005-19957 Japanese Patent No. 3128354

  However, in the load control technique of Patent Document 1, a load sensor is arranged for each nozzle, and the load applied to the component by the nozzle is measured for each nozzle. Therefore, it is necessary to arrange the load sensors as many as the number of nozzles. Therefore, in the case of a multi-nozzle head, the structure is complicated, the weight of the head is reduced and the size is reduced, and the probability of failure is also increased, so the maintainability such as head replacement also deteriorates. It will be.

  In the case of the load control technique of Patent Document 2, since the load sensor is arranged on the substrate support side, it is sufficient that the number of load sensors is at least three. Since the load applied to the component can be measured only when the component is mounted on the board, other load control cannot be performed. For example, since the load at the time of component adsorption or fluxer transfer cannot be measured, the load control at that time becomes impossible. However, if load sensors are arranged on the support side of the component suction part and the support side of the fluxer, it is possible to control the load at the time of component suction and fluxer transfer, but it is not possible to attach a load sensor to each support side. In general, it is not practical because the number of components used is large and the component supply device needs to be frequently attached to and detached from the surface mounter.

  In order to solve the above-described conventional problems, the present invention includes a head unit that does not obstruct the weight reduction or reduction of the head without complicating the structure even in the case of a multi-nozzle head. It is an object to provide a surface mounting apparatus.

The present invention relates to a surface mounting apparatus having a head unit having a head plate guided and moved in one horizontal axis and a mounting head fixed to the head plate, and a vertical direction between the mounting head and the head plate. A linear sensor guided by a pair of rails extending in the direction of the one axis is opposed to the back surface of the head plate, and a load sensor for measuring the load of the head plate is provided. The mounting head is fixed to the front surface with the load sensor interposed therebetween, thereby solving the problem.

  In the present invention, the mounting head may be fixed to the head plate at at least three locations, and a load sensor may be interposed at each fixed location.

  According to the present invention, the mounting head is fixed to the head plate so as to be movable in a vertical direction via linear guides arranged opposite to each other, and a load sensor is provided at a central position between the linear guides. Good.

  According to the present invention, since the mounting head is fixed to the head plate guided and moved in the horizontal direction via the load sensor capable of detecting the load in the vertical direction, the suction nozzle mounted on the mounting head is fixed. Regardless of the number, it is possible to accurately control the load not only when the electronic component is mounted but also when attracted, without complicating the structure.

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

  The surface mounting apparatus according to the first embodiment of the present invention has the same basic configuration as that shown in FIG. 1 except for the head unit.

  In general, the head unit 30 is composed of a head plate 32, a mounting head 10 and the like, as shown in FIG. 3 where the relationship between the X axis and the Y axis viewed from above is shown in FIG. .

  The head plate 32 is fixed to the rail 12A of the X-axis moving mechanism 12 via a linear guide 36 so as to be movable in the X-axis direction, and is also unillustrated by the Y-axis moving mechanism 14 in the Y-axis direction. It is driven by a ball screw or a linear motor.

  In the present embodiment, a load sensor capable of measuring a load in the vertical direction is interposed between the head 10 and the head plate 32, and the head is fixed to the head plate 32 so that the entire load of the head 10 is applied thereto.

  Here, a quartz piezoelectric force sensor is used as the load sensor 40 as shown in FIG. In the figure, the state in which the head 10 is fixed with the fixing screw 42 is shown only at one location, but as a whole, four locations are fixed, and the load sensor 40 is attached to each fixing position. Therefore, when the loads applied to the load sensors 40 are added up, the mass of the head 10 + the load applied by the head 10 can be measured.

  If the head mass is measured in advance and the head mass is subtracted from the total value of the load sensor 40, the load applied by the head can be calculated. For example, when the total value of all load sensors is 5.1 kg and the head mass is 5 kg, the load applied by the head 10 is 0.1 kg.

  As the load sensor (quartz piezoelectric force sensor) 40, in addition to the quartz element sensitive to the axial compression force Fz of the fixing screw 42, two quartz crystals sensitive to the surface shearing force (Fx, Fy) are used. A three-component force sensor combining elements can be used effectively.

  In general, the head 10 has a nozzle 10A arranged in parallel with the X-axis (or Y-axis) in parallel with a parallel head (six nozzles 10A in FIG. 3 are arranged in parallel), for example, JP-A-2005-26723. It is divided into two types of rotary heads in which nozzles are arranged on a circular arc centering on a rotation axis as disclosed in Japanese Patent Publication. In this embodiment, a parallel head is employed, but the present invention can also be applied to a rotary head.

  Normally, in the parallel head, when picking up the components, the nozzles pick up the components at the same time for tact UP, and the component mounting can be performed for each nozzle individually. Also, in the rotary head, component suction and component mounting are usually performed for each nozzle individually.

  If each nozzle individually operates and applies a load to a component, the load applied to the component can be controlled by controlling the operation of the lifting mechanism (Z axis) of the nozzle. However, when using a parallel head where multiple nozzles apply load at the same time, when simultaneously picking up each nozzle component, the individual load applied by each nozzle cannot be calculated, and only the sum of the loads cannot be calculated, so load control cannot be performed. .

  In the case of a flip chip, it is only necessary that the component suction can be performed without damaging the component, and in order to mount the component with a certain load, load control is often required. Therefore, there is no problem even if the load control cannot be performed as in the simultaneous suction of each nozzle of the parallel head.

  In this case, the nozzle employs a structure that uses a spring S for the purpose of reducing the impact force by the suction portion N as shown in FIG. 5, and further controls the nozzle lowering speed during component suction. Thus, measures may be taken so as not to damage the nozzle when it hits the part.

  If there is a part that needs load control at the time of picking up a part in the parallel head, the load by lifting and lowering the nozzle that picks up the part is not performed at the same time as the lifting and lowering action of another nozzle. Load control of only the parts that need to be controlled is also possible.

  The control method will be described below. In this embodiment, the control configuration is as shown in FIG. 6, and as described above, the six nozzles 10A of No. 1 to No. 6 are arranged in the head 10, and the head 10 is a head. A plate (in the figure, a head fixing portion) 32 is fixed at four positions, and No. 1 to No. Four load sensors 40 are interposed. The load summing device 50 sums up the measured values of the four load sensors 40 and sends the summed value to the control device 60.

  Next, the flow of control will be described with reference to the flowchart of FIG.

  The nozzle is moved to a load control execution position such as a suction position, a mounting position, and a fluxer transfer position (step 1). After the movement is completed and set, the head mass is measured by the load adding device 50 (step 2). The target load that the nozzle applies to the component and the time for which the load is applied are read from the storage device (step 3). The nozzle 10 </ b> A is lowered until the measured value of the load summing device 50 reaches the target load + head mass by the nozzle lifting device (step 4). When the target load is reached, the descent of the nozzle 10A is stopped (step 6), and the load is held for a time to apply the load (step 7). Thereafter, the nozzle is raised by the nozzle lifting mechanism to end the load control (step 8).

  According to the present embodiment described in detail above, the head structure is complicated and maintainable only by fixing the head by sandwiching the load sensor (quartz piezoelectric force sensor) 40 between the head 10 and the head plate 32. There is no deterioration, and it is possible to control the load applied to the component by the nozzle 10A without hindering the weight reduction or size reduction of the head 10. At the same time, the nozzle 10A can control the load on the component at any time such as component suction, fluxer transfer, and component mounting. Furthermore, if the head mass does not change, the nozzle load can be controlled in any head regardless of the arrangement and number of nozzles. Therefore, the degree of freedom is extremely high. By controlling the number of expensive load sensors used, load control is easily realized, and there is almost no impact on tact-up requirements.

  FIG. 8 shows the characteristics of the main part of the second embodiment, which corresponds to a structure in which a load cell 44 is provided instead of the quartz piezoelectric force sensor as the load sensor 40 of the first embodiment shown in FIG. The rest is the same. Here, for convenience, two upper and lower load cells 44 are shown. As the load cells 44, a shear-sensitive type (beam type) can be used.

  FIG. 9 is a perspective view corresponding to FIG. 3 and showing the features of the head unit 30 of the third embodiment.

  As shown in this figure, in this embodiment, a linear guide 36 that allows the head 10 to be guided and moved in the vertical direction (up and down direction) is disposed on the head plate 32 so as to oppose left and right, and the central position between the two. One load cell 44 is fixed as a load sensor. Then, with the head 10 in contact with the load cell 44, the left and right positions thereof are fixed to the left and right linear guides 36 with screws (not shown) to form the head unit 30.

  By doing so, since the movement of the head 10 when a load is applied to the nozzle 10 </ b> A is restricted in the vertical direction, the load of the entire head can be measured by one load cell (load sensor) 44.

  In the first and second embodiments, the case where the head 10 is fixed to the head plate 32 in four places has been described. However, it is sufficient if the vertical plane of the head 10 can be defined. Further, the load sensor may be other than a load cell or a piezoelectric element, and any type can be used as long as it can be used.

The perspective view which shows the principal part of a surface mounting apparatus Main part plan view showing the relationship between the head unit and the XY axes Exploded perspective view showing the characteristics of the head unit Partial sectional view showing features of the first embodiment Sectional drawing showing an example of a suction nozzle Block diagram showing the outline of the control configuration of the surface mount device Flow chart showing the operation of the embodiment Partial sectional view showing features of the second embodiment Exploded perspective view showing features of the third embodiment

Explanation of symbols

10 ... Mounting head (head)
10A ... Suction nozzle (nozzle)
30 ... Head unit 32 ... Head plate 36 ... Linear guide 40 ... Load sensor (crystal piezoelectric force sensor)
44 ... Load cell

Claims (3)

In a surface mount device having a head unit having a head plate guided and moved in a horizontal axis and a mounting head fixed to the head plate, a vertical load is measured between the mounting head and the head plate. A load sensor is installed ,
On the back surface of the head plate, linear guides respectively guided by a pair of rails extending in the uniaxial direction are opposed to each other, and
The surface mounting apparatus , wherein the mounting head is fixed to a front surface of the head plate with the load sensor interposed therebetween .   The surface mounting apparatus according to claim 1, wherein the mounting head is fixed to the head plate at at least three locations, and a load sensor is interposed at each fixing location.   2. The mounting head is fixed to the head plate so as to be movable in a vertical direction via linear guides arranged opposite to each other, and a load sensor is provided at a central position between the linear guides. Surface mount equipment.

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