JP2008205339A - Measuring method of flatness of board mounting table - Google Patents

Abstract

A flatness measurement method that facilitates measurement of flatness of a substrate mounting table and readjustment when the flatness deteriorates is provided.
In a component mounting apparatus that performs a pressure control operation with a component mounting head while detecting the amount of pressure applied to a component or a substrate when mounting the component, on a lower portion of a substrate mounting table on which a substrate on which the component is mounted is placed. A load detector (pressure sensor) for detecting a load applied to the substrate is provided, and a jig nozzle 52 is mounted on the component mounting head 4 so as to contact the substrate mounting table at a predetermined three or more plane positions. The distance from the origin of the jig nozzle 52 to the substrate mounting table when the output of the load detector reaches a predetermined value is detected at the three or more planar positions.
[Selection] Figure 3

Description

  The present invention relates to a method for measuring the flatness of a substrate mounting table in a component mounting apparatus, and in particular, a component mounting apparatus that performs a pressure control operation with a component mounting head while detecting the amount of pressurization applied to the component and the substrate during component mounting. The present invention relates to a method for measuring the flatness of a substrate mounting table, which can be used for measuring the flatness of the substrate mounting table with a simple configuration and for readjustment when the flatness deteriorates.

  Controls the pressing force acting on components when mounting various electronic components that are vulnerable to the pressing force, such as semiconductor chips, in a component mounting device for mounting various electronic components at predetermined positions on a printed circuit board. As a technique for doing this, Patent Document 1 is proposed.

  In this component mounting apparatus, as shown in FIG. 1, a substrate mounting table (also “elevating plate”) in a transfer unit (also “substrate transfer mechanism”) 7 of the component mounting apparatus (“electronic component mounting apparatus” in Patent Document 1) is used. ”) A pressure sensor (also“ force sensor ”) 6 is provided inside the substrate support pin 87 of the substrate elevating mechanism 8 to support the wiring board (also“ printed circuit board ”) 31 on the 85. Based on this signal, the microcomputer controls the lifting mechanism of the head so that the electronic component 3 is mounted on the wiring board 31 with a predetermined pressure.

  In the figure, 32 and 33 are guide rails, 32a and 32b are stoppers, 4 is a suction head mechanism disposed on the component mounting head, 41 is a suction nozzle, and 71 is for driving the roller 72 of the transport unit 7. A motor 81 is a column of the substrate lifting mechanism 8, 82 is a base fixed at a fixed height by the column 81, 83 is a guide member provided at the four corners of the base 82, and 84 is a shaft. , 88 are air cylinders.

Japanese Patent No. 3128354 (FIG. 9)

  In recent years, components to be mounted have been miniaturized, and in order to mount small components with high accuracy, it is necessary to detect and maintain the flatness of the substrate mounting table 85 on which the wiring substrate 31 is mounted. There is a problem in that the flatness deteriorates with time due to a shift in mechanical adjustment, thereby deteriorating the mounting accuracy of components. Therefore, it is necessary to readjust the flatness of this board mounting table on a regular basis. However, a special measuring instrument such as a dial gauge is used to readjust the flatness. Need.

  In Patent Document 1, the pressure sensor 6 is provided inside the substrate support pin 87, but the mounting accuracy and perpendicularity between the substrate support pin 87 and the substrate mounting table 85 cannot be obtained. It was necessary to readjust the flatness of the substrate mounting table 85 with a gauge or the like.

  The present invention was made to solve the above-mentioned conventional problems, and by using a load detector that was conventionally used only for load control, the flatness of the substrate mounting table can be measured with a simple configuration, An object is to enable readjustment when flatness deteriorates.

  The present invention provides a component mounting apparatus that performs a pressure control operation with a component mounting head while detecting the amount of pressure applied to a component and a substrate when mounting the component. A load detector for detecting the load applied to the substrate is provided, a jig nozzle is mounted on the component mounting head, and the substrate mounting table is brought into contact with the substrate mounting table at a predetermined three or more plane positions. The above-mentioned problem is solved by the method for measuring the flatness of the substrate mounting table, wherein the distance from the origin of the jig nozzle to the substrate mounting table when the value reaches a predetermined value is detected at the three or more planar positions. It is a thing.

  The flatness measurement by the above-described method can be performed again at a later time, and the change with time of the flatness of the substrate mounting table can be detected.

  According to the present invention, it is possible to measure the flatness of the substrate mounting table without increasing the cost by using a pressure sensor installed for pressure control during component mounting. As a result, the quality of the mounting position at the time of component mounting can be maintained, and further, when the flatness of the board mounting table exceeds the set specified range, the user can be urged to readjust. .

  In addition, when the flatness of the substrate mounting table deteriorates and readjustment is required, readjustment of flatness can be easily performed without the need for a special measuring instrument such as a dial gauge. .

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

  FIG. 2 shows the overall configuration of an embodiment of a component mounting apparatus according to the present invention. In FIG. 2, a component mounting head (also simply referred to as a mounting head or a head) 4 includes a pressurizing device that sucks and holds components and pressurizes, and a recognition device (not shown) that corrects the position of the mounting head 4. . The mounting head 4 is provided on an X-axis gantry 2X that moves the component mounting apparatus in the X-axis direction. The mounting head 4 and the X-axis gantry 2X are attached to a Y-axis gantry 2Y for moving in the Y-axis direction of the component mounting apparatus. Below the X-axis gantry 2 </ b> X is a transport unit 7, and a substrate mounting table 85 is installed in the transport unit 7.

  A detailed configuration of the mounting head 4 is shown in FIG. The mounting head 4 has a head base 42 that is connected and fixed to the X-axis gantry 2X. An upper portion of the head base 42 includes a θ-axis motor 43 for rotating the components, a vertical rotation drive unit bearing 44 composed of a spline bearing and a bearing, and a vertical rotation drive shaft 45. Further, a belt 46 for transmitting the power of the θ-axis motor 43 to the vertical rotation drive shaft 45 and a Z-axis motor 48 for vertically moving the vertical Z drive unit 47 are attached. The screw 49 is connected to a screw portion 49 a of the screw 49. A nut portion 49b of a ball screw 49 is fixed to the vertical Z drive portion 47. When the Z-axis motor 48 is rotated, the vertical Z drive portion 47 is moved up and down by the nut portion 49b of the ball screw 49. It has a possible structure.

  A nozzle shaft 50 is connected below the vertical rotation drive shaft 45. A nozzle chuck mechanism 51 is provided at the lower end of the nozzle shaft 50, and the jig nozzle 52 can be held and replaced in place of the suction nozzle 41 (see FIG. 1) similar to the conventional example. The jig nozzle 52 is a nozzle for use in the present invention, which does not have a function of sucking and holding components, unlike a suction nozzle used in a normal component mounting apparatus. The size of the jig nozzle 52 is compatible with that of the suction nozzle, and can be placed on the nozzle exchange base for the suction nozzle and can be chucked by the nozzle chuck mechanism 51.

  Next, the structure of the transport unit 7 according to the present invention is shown in FIG. FIG. 4 is a perspective view of the substrate mounting table 85 (for the sake of explanation, the substrate mounting table 85 is transparent). Under the substrate mounting table 85, pressure sensors 76 are arranged and fixed at the four corners. The outputs of the four pressure sensors 76 are input to the amplifier 78 via the adder 77.

  The configuration of the control system of the component mounting apparatus is shown in FIG. On the head 4, there are a Z-axis motor 48, a θ-axis motor 43, drivers 53 and 54, a Z-axis encoder 55, and a θ-axis encoder 56. On the main body, the pressure sensor 76, an adder 77, a pressure sensor amplifier 78, and a CPU 1 for controlling the operation are mounted.

  The drivers 53 and 54 of each motor are connected to the CPU 1 and operate in response to a command from the CPU 1. The output of the pressure sensor amplifier 78 is connected to the CPU 1, and the CPU 1 reads the output value of the pressure sensor amplifier 78.

  A method for detecting the flatness of the substrate mounting table 85 and adjusting the flatness in the above configuration will be described below.

  First, the flatness of the substrate mounting table 85 in FIGS. 2 and 4 is adjusted in advance using a dial gauge or the like. 2 is moved above the substrate mounting table 85 by operating the X-axis gantry 2X and the Y-axis gantry 2Y.

  Next, the operation of the mounting head 4 in the Z-axis direction will be described with reference to FIG.

  The mounting head 4 is driven at a specific position on the substrate mounting table 85 by driving the Z-axis motor 48 to lower the vertical Z driving unit 47 and the jig nozzle 52.

  When the tip of the jig nozzle 52 comes into contact with the substrate mounting table 85, pressure is generated on the substrate mounting table 85, and the force is transmitted to the pressure sensor 76, and the contact timing of the jig nozzle 52 is detected. Then, after the contact of the jig nozzle 52 is detected, the lowering of the jig nozzle 52 is stopped. At this time, the CPU 1 in FIG. 5 controls the lowering of the jig nozzle 52, and determines the movement distance of the jig nozzle 52 in the Z-axis direction, that is, the distance from the origin of the jig nozzle 52 to the substrate mounting table 85. Can be measured.

  After the measurement is completed, the X-axis gantry 2X and the Y-axis gantry 2Y in FIG. 2 are operated again, and the mounting head 4 is moved to a position different from the previous position. Similarly, from the origin of the jig nozzle 52 to the substrate mounting table 85. Measure the distance.

  In this way, the distance from the origin of the jig nozzle 52 to the substrate mounting table 85 is measured at three or more planar positions on the substrate mounting table 85, and recorded in a recording device (not shown) in the CPU 1 in FIG. Keep it.

  After using this component mounting apparatus for a certain period, the distance from the origin of the jig nozzle 52 to the substrate mounting table 85 is measured again at the same position as that previously recorded in the recording apparatus by the method described above. . Then, it is possible to detect how much the flatness of the substrate mounting table 85 has deteriorated by comparing the distance value recorded immediately after the adjustment of the flatness with the distance value measured after this period of use. It becomes possible. In addition, an allowable range of flatness is set in advance, and when the deterioration of flatness exceeds the allowable range, it is possible to prompt the user to readjust the surface degree.

  Furthermore, when performing readjustment of flatness, it has conventionally been necessary to use a special measuring instrument such as a dial gauge, which requires specialized knowledge and technology. The value of how much the flatness deteriorated is recorded in the CPU 1 of 5. Therefore, the flatness adjuster can readjust the flatness with reference to the value recorded in the CPU 1, so that a special measuring instrument such as a dial gauge is not required. After the adjustment of the flatness, the distance from the origin of the jig nozzle 52 to the substrate mounting table 85 is again measured at the same position as that previously recorded in the recording apparatus by the method described above. Can be confirmed to be within the allowable range.

  If the present invention is applied to a component mounting apparatus in which the pressure sensor 76 is disposed below the board mounting table 85, a separate pressure sensor is not necessary. As shown in FIG. 1, when the pressure sensor 6 is provided on the substrate mounting table 85, the present invention is similarly applied by moving the pressure sensor 6 below the substrate mounting table 85. it can.

  In this embodiment, since the adder 77 is provided on the output side of the pressure sensor 76, the configuration is simple. It is also possible to omit the adder 77 and determine contact based on the output of each pressure sensor 76. The arrangement positions of the pressure sensors 76 are not limited to the four corners of the substrate mounting table 85, and the arrangement number is not limited to four.

Sectional drawing which shows the structure of the prior art described in patent document 1 The perspective view which shows the principal part of the whole structure of the components mounting apparatus which concerns on this invention Sectional view showing the configuration of the component mounting head The perspective view which similarly shows the arrangement of the pressure sensor Block diagram showing the configuration of the control system

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 ... Adsorption head 7 ... Conveyance unit 47 ... Vertical Z drive part 48 ... Z-axis motor 50 ... Nozzle shaft 51 ... Nozzle chuck mechanism 52 ... Jig nozzle 76 ... Pressure sensor 85 ... Substrate mounting table

Claims (2)

In the component mounting device that performs pressure control operation with the component mounting head while detecting the amount of pressure applied to the component and board at the time of component mounting,
A load detector for detecting the load applied to the board is provided at the bottom of the board mounting table on which the board on which the components are mounted is placed.
A jig nozzle is mounted on the component mounting head, and is brought into contact with the substrate mounting table at a predetermined three or more plane positions,
A method for measuring the flatness of a substrate mounting table, wherein the distance from the origin of the jig nozzle to the substrate mounting table when the output of the load detector reaches a predetermined value is detected at the three or more planar positions. .   A flatness measurement method for a substrate mounting table, wherein the flatness measurement by the method according to claim 1 is performed again after a while, and a change with time of the flatness of the substrate mounting table is detected.

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