JPH10151402A - Sealant discharge amount control method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To control the discharge amount of a sealant to a circuit board so as to be constant. SOLUTION: A first control data obtained from a relationship between a use elapsed time of a sealant A and a discharge pressure by a discharge pressure determination unit 21 of a control unit 20 and a remaining amount of the sealant A in a syringe 8 are determined. The pressure (discharge pressure) data to be applied to the upper part of the syringe 8 is determined based on the second control data obtained from the relationship with the discharge pressure, and the discharge pressure calculator 22 determines the pressure (discharge pressure) data based on the pressure data from the discharge pressure determiner 21. Then, the pressure value applied to the actual syringe 8 is calculated. The pressure application unit 23 applies a pressure P for discharging the sealant A to the syringe 8 based on the pressure value calculated by the discharge pressure calculation unit 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting an electronic component, such as a bare chip, on a circuit board, the amount of a sealant used for sealing the electronic component to the circuit board being constant. And a method for controlling the amount of discharge of the sealant.

[0002]

2. Description of the Related Art Conventionally, a sealant used for sealing an electronic component to a circuit board is formed from a lower part of the syringe by a constant pressure applied from an upper part of a syringe for storing the sealant. Is controlled so that a certain amount is discharged.

[0003]

In the prior art, when a sealant having a relatively low viscosity is used, the change in the discharge pressure at the lower portion of the syringe during actual operation is small, and the pressure applied from the upper portion of the syringe is small. Since the discharge amount of the sealant corresponds to the given constant pressure, it is easy to make the discharge amount fall within an allowable range as a good product condition.

However, in the case of a sealant having a relatively high viscosity, even if a constant pressure is applied from the upper part of the syringe due to a change over time due to the use time or the remaining amount in the syringe, the discharge pressure at the lower part of the syringe during actual operation. Gradually changes, and the change is large. As shown in FIG. 6, the actual discharge amount may be out of the allowable range set based on the target discharge amount as a non-defective condition.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for controlling a discharge amount of a sealant which can control the discharge amount of the sealant to a circuit board so as to be constant.

[0006]

According to the present invention, there is provided a sealant for controlling a discharge amount of a sealant discharged from a syringe for sealing an electronic component to a circuit board. In the discharge amount control method, control data for controlling the discharge amount of the sealant is generated based on the remaining amount of the sealant in the syringe and the elapsed time when the sealant has been used, and the control data Controlling the discharge amount of the sealant from the syringe, thereby controlling the discharge amount of the sealant according to the characteristics of the sealant, the state of use, and the like. And the discharge amount can be prevented from changing during operation.

The present invention also provides control data for measuring the discharge amount of the sealant during the discharge operation of the sealant and controlling the discharge amount of the sealant based on the measured value. Is corrected, so that the ejection amount can be controlled with higher accuracy so as to be a constant amount.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing an outline of a sealant applying apparatus for explaining an embodiment of a control method according to the present invention, wherein 1 is an apparatus main body, and 2 is a plurality of circuit boards 3 housed. A magazine section 4 provided in the magazine section 2 for moving the circuit board 3 to a predetermined transport line;
Reference numeral 5 denotes a substrate transport guide unit, and reference numeral 6 denotes an application stage movably installed on the substrate transport guide unit 5 and receiving the circuit board 3. Reference numeral 7 denotes a coating head, which is a syringe 8 for discharging a sealing agent contained therein to apply it to the circuit board 3, a camera 9 for board recognition, and sealing from the syringe 8 as described later. A control unit and the like for controlling the amount of the agent discharged are provided.

[0010] Further, reference numeral 10 denotes a position for moving the coating stage 6 in the X-Y direction with respect to the coating head 7 and positioning the sealing agent to be discharged and applied to a predetermined portion of the circuit board 3. A driving unit, 11 is a cleaning unit of the coating stage 6, 12 is a pushing unit for removing the circuit board 3 coated with the sealing agent from the coating stage 6 and moving it to the substrate guide unit 5, and 13 is a sealing agent. Reference numeral 14 denotes a stock camera for temporarily stocking the circuit board 3 on which is coated and moving the board to the next step, and a TV camera 14 for projecting a board image based on an image signal from the camera 9.

FIG. 1 is a block diagram showing a schematic configuration of a control section of the coating head 7. The control section 20 discharges the sealing agent A stored in the syringe 8 from the syringe 8 by a fixed amount. A discharge pressure determining unit 21 for determining pressure (discharge pressure) data to be applied to the upper part of the syringe 8, and a discharge pressure calculation for calculating an actual pressure value to be applied to the syringe 8 based on the pressure data from the discharge pressure determining unit 21. Unit 22 and a discharge pressure calculation unit
Based on the pressure value calculated by 22, the pressure applying unit 23 applies a pressure P for discharging the sealant A to the syringe 8.

Further, the control unit 20 includes a discharge amount measuring unit 25 including a sensor for measuring the discharge amount of the sealant A actually discharged from the syringe 8, and a target value of the discharge amount and measurement as described later. A discharge amount difference calculating unit 26 for calculating a difference from the calculated actual discharge amount, and a correction value calculation for calculating a correction value of the pressure applied to the syringe 8 from the obtained discharge amount difference and outputting the correction value to the discharge pressure determining unit 21. A part 27 is provided.

Next, a method for controlling the discharge amount of the sealant according to the present invention, which is applied to the sealant applying apparatus having the above-described configuration, will be described.

In the discharge amount determining section 21, a sealant used (for example, Epo. Tek K5022 manufactured by Epoxy Technology) is used.
-11D or Epo. Tek U300), the relationship between the elapsed time of use and the discharge pressure as shown in FIG. 3 was measured in advance (the actual values are shown in Table 1). (1) While the control data is input, the relationship between the remaining amount of the sealant in the syringe 8 and the discharge pressure is measured in advance as shown in FIG. Is input, and pressure data for a fixed amount of the sealant actually discharged from the syringe 8 is determined based on both of the control data.

[0015]

[Table 1]

[0016]

[Table 2]

On the basis of the pressure data, the discharge pressure calculating section 22 in FIG. 1 sets the time-discharge time in FIG. 5 so that the discharge amount falls within an allowable range set based on the target discharge amount shown in FIG. An actual pressure value applied to the syringe 8 is calculated as shown in a diagram showing a relationship example of the pressure (P). Based on the pressure value data output from the discharge pressure calculation unit 22, the pressure application unit 23 applies a pressure P for discharging the sealant A to the syringe 8.

Further, the discharge amount measuring unit 25 measures an actual discharge amount from the syringe 8 at a timing of measurement appropriately set in actual operation, and calculates a difference between the actual discharge amount and the target discharge amount. The correction value is calculated by the correction value calculation unit 27 so that the difference is within the allowable range, the correction value data is output to the discharge pressure determination unit 21, and the correction value data is output to the actual syringe 8 by the discharge pressure calculation unit 22. Correct the applied pressure value. Then, based on the corrected pressure value data, a pressure applying unit
23 applies a pressure P for discharging the sealant A to the syringe 8.

More specifically, for example, when the target discharge amount is 10.0 mg, the actual discharge amount is 9.2 mg, and the allowable range of the discharge amount is ± 10% of the target discharge amount, the correction is performed. The target error is obtained by calculating 1/2 of the difference between the actual ejection amounts as a correction coefficient. The reason why 1/2 of the difference is used as the correction coefficient is that the difference between the actual ejection amount and the target ejection amount may exceed the allowable range if used as the correction value as it is, and is within the allowable range. This is because it is sufficient to set a coefficient of correction sufficient for the correction.

Therefore, the correction value of the pressure is as shown in (Equation 1).

[0021]

## EQU1 ## Correction value = (10.0−9.2) × 1/2 = 0.4 (mg) Then, a correction pressure for canceling this correction value is added, and the control pressure from the next is added as in (Expression 2). The value is determined.

[0022]

## EQU2 ## Correction pressure = control pressure × (0.4 / 10.0) By performing pressure control in this way, a discharge process that matches the characteristics of the sealant used is performed.
If the properties of the sealant are similar, the same algorithm can be used to control the constant discharge amount.

Further, the discharge amount of the sealant can be controlled within the range of the non-defective product condition, and as a result, the operation of applying the sealant can be stabilized. In addition, an expensive sealant can be used without waste, which is advantageous in terms of cost.

Further, it is possible to cope with the fact that the viscosity characteristic changes depending on the kind of the sealing agent or even the lot of the same sealing agent.

[0025]

As described above, according to the method for controlling the discharge amount of the sealant of the present invention, the discharge amount of the sealant is controlled in accordance with the characteristics of the sealant, the state of use, and the like. In addition, it is possible to prevent the discharge amount from changing during operation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a control unit in a coating head of FIG. 2 for explaining an embodiment of the present invention.

FIG. 2 is a perspective view showing an outline of a sealant application device for explaining an embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a use elapsed time of a coating agent and a discharge pressure.

FIG. 4 is a diagram showing a relationship between the remaining amount of a sealant in a syringe 8 and a discharge pressure.

FIG. 5 is a diagram exemplifying a relationship between pressure applied to the syringe and time set by the method according to the embodiment;

FIG. 6 is an explanatory diagram of a discharge amount allowable range of a coating material.

[Explanation of symbols]

8: syringe, 20: control unit, 21: discharge pressure determination unit,
22: discharge pressure calculation section, 23: pressure addition section, 25: discharge amount measurement section, 26: discharge amount difference calculation section, 27: correction value calculation section.

Claims (2)

[Claims] 1. A method for controlling an amount of a sealant discharged from a syringe to seal an electronic component to a circuit board, the method comprising the steps of: And generating control data for controlling the discharge amount of the sealant based on the elapsed time when the sealant has been used, and controlling the discharge amount of the sealant from the syringe by the control data. A method for controlling a discharge amount of a sealant. 2. A method for measuring a discharge amount of a sealant during a discharge operation of the sealant and correcting control data for controlling the discharge amount of the sealant based on the measured value of the discharge amount. The method for controlling a discharge amount of a sealant according to claim 1, wherein: