JPH0234666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for attaching adhesive to predetermined locations on a printed circuit board when temporarily fixing electronic components, particularly chip-type electronic components, to a printed circuit board. This invention relates to an adhesive coating device.

Adhesive applicators for temporarily fixing electronic components to printed circuit boards are available using the transfer method, dispenser method, and screen printing method. Consisting of a pin and an adhesive pool,
The adhesive was applied to the printed circuit board by placing the tip of the applicator pin in the adhesive pool. Therefore, there are problems such as stringy adhesive, unstable amount of adhesion to the tip of the applicator pin, and unstable amount of adhesion due to fluctuations in the liquid level of the adhesive pool. The adhesive may spread to the lands that are electrically connected to the parts, causing poor continuity or poor adhesion.
The problem is that it is difficult to switch types.

As shown in Japanese Utility Model Application Publication No. 55-145330, a roller whose lower part is housed in a case containing adhesive is provided, and by rotating this roller, the adhesive is held on the outer circumferential surface of the roller. If the adhesive is transferred to the applicator pin by bringing the applicator pin into contact with the outer peripheral surface of the roller, the amount of adhesive that adheres to the applicator pin will be much more stable than in the conventional example described above. No, because the amount of adhesive retained on the outer peripheral surface of the roller is greatly affected by the viscosity of the adhesive, it is not possible to control the amount of adhesive attached to the applicator pin with high precision, and even though it is adhered, It is not possible to adjust the amount of adhesive depending on the size etc.

The present invention has been developed in view of these points, and its purpose is to stabilize the amount of adhesive that adheres to the applicator pin and to ensure that the required amount of adhesive is applied only to the required locations on the printed circuit board. An object of the present invention is to provide an adhesive applicator that can not only apply adhesive to the adhesive but also easily adjust the amount of adhesive applied.

The present invention will be described below.The present invention includes a case in which the lower part of a roller that is driven to rotate around a substantially horizontal axis is housed in a case filled with adhesive, and a doctor knife is opposed to the circumferential surface of the roller with a gap therebetween. It consists of an adhesive supply unit and an applicator pin whose tip contacts the circumferential surface of the roller, and the roller has a groove extending all the way around the outer circumferential surface of the roller, and the applicator pin can selectively contact the outer circumferential surface of the roller and the groove. It is characterized by the fact that a constant amount of adhesive is always kept on the circumferential surface of the roller using a doctor knife, and the adhesive that adheres to the tip of the applicator pin that is in contact with the circumferential surface of the roller is The amount of adhesive is stabilized, and the amount of adhesive applied to the applicator pin can be controlled by bringing the applicator pin into contact with the outer peripheral surface of the roller or by contacting the groove that extends all the way around the outer peripheral surface of the roller. The amount of adhesion can be adjusted. Next, the present invention will be described in detail based on the illustrated embodiment. FIG.
This mounting machine, which applies adhesive and mounts electronic components, has a movable head 1 whose rotation in the three axes of XYZ and around the Z axis is controlled, and a control for programming the control of the movable head 1. In addition, multiple inline parts feeders 3 for supplying electronic components are installed, and a replacement tool holder 6 and an adhesive are placed next to a holding table 5 that fixes a printed circuit board 4 on the top surface. A supply unit 7 is installed. The exchange tool holder 6 has a plurality of tools set on its upper surface, such as a coating pin 10 and an electronic component suction pin 9, and these tools are automatically exchanged and attached to the movable head 1. It is becoming more and more common. Set the printed circuit board 4 on the holding stand 5,
Next, when the operation is started, the applicator pin 10 is first glued to the movable head 1 from the exchange tool holder 6, and the applicator pin 10 is glued to the movable head 1 by reciprocating between the adhesive supply unit 7 of the movable head 1 and the printed circuit board 4. At step 10, adhesive is applied to the required parts of the printed circuit board 4, and then the tool attached to the movable head 1 is replaced with an electronic component suction pin 9 to connect the in-line parts feeder 3 and the printed circuit board 4. The reciprocating movement of the movable head 1 places the electronic component on the adhesive-adhered portion of the printed circuit board 4.

Now, as shown in FIG. 2, the adhesive supply unit 7 consists of a case 11 which has a double structure of an outer case 12 and an inner case 13, and a geared motor 15 that rotates the adhesive at a very low speed around a substantially horizontal axis. It is composed of a rotationally driven roller 14 and a doctor knife 16, and a geared motor 15, a block of rollers 14, and an inner case 13 are detachably attached to an outer case 12. This is so that the adhesive placed in the inner case 13 can be changed by replacing the inner case 13, and the adhesive can be easily replenished. The roller 14 is housed in the case 11 so that its lower part is immersed in the adhesive in the inner case 13.
A doctor knife 16 fixed to the roller 14 is arranged to face the circumferential surface of the roller 14 with a small gap therebetween.

Furthermore, as is clear from FIG. 3, the roller 14 is provided with a groove 17 extending over the entire circumference at one axial end of its circumferential surface. The applicator pin 10, which attaches the adhesive held on the circumferential surface of the roller 14 to its tip by contacting the circumferential surface of the roller 14 or inserting it into the groove 17, is shown in FIG. A hole 18 in the axial direction is provided at the tip, and a notch 19 is formed on the side surface of the tip.
A hole 18 communicates with the.

Therefore, in the adhesive supply unit 7,
The adhesive is held on the circumferential surface of the roller 14 rotating at a slow speed, and the amount of adhesive held is always kept constant by a doctor knife 16. Z of
Due to the movement in the axial direction, that is, the vertical direction, the amount of adhesive that adheres to the tip of the application pin 10 that is brought into contact with the circumferential surface of the roller 14 is also stabilized. Therefore, by bringing the applicator pin 10 to which the adhesive is adhered into contact with the surface of the printed circuit board 4, the adhesive 20 is transferred onto the printed circuit board 4.
The contact area with the printed circuit board 4 is stable, and there is no protrusion into the land. Moreover, since the applicator pin 10 has a hole 18 at its tip and communicates with the notch 19, a portion of the adhesive adhered to the applicator pin 10 is absorbed into the central hole.
When the adhesive 20 enters into the hole 8 and is transferred to the printed circuit board 4, the adhesive in this hole 18 is pulled out.
As shown in FIG. 5, the height h is higher than the contact area with the printed circuit board 4, and even when the electronic component is a cylindrical chip as shown in FIG. The contact area is large, and the adhesive strength is high. FIG. 7 shows a case where the contact area is large and the height is low, and as is clear from the figure, in this case, the bonding area between the electronic component 21 and the adhesive 20 becomes small.

The groove 17 provided in the roller 14 is also filled with adhesive by the doctor knife 16.
Therefore, a constant amount is always maintained.
Here, if the applicator pin 10 is inserted into this groove 17, the amount of adhesive that can be attached to the applicator pin 10 can be increased, and the gap between the hole 18 and the notch 19 in the applicator pin 10 can be increased. The existence is
Since it is possible to increase the amount of adhesive that adheres to the applicator pin 10, it is suitable for use with relatively large electronic components, such as flat pack ICs.
Even in such cases, a sufficient amount of adhesive can be applied. In particular, by controlling the downward movement of the movable head 1 when applying adhesive to the applicator pin 10 and controlling the amount of insertion of the applicator pin 10 into the groove 17, The amount of adhesive applied to the applicator pin 10 can be adjusted over a wide range depending on whether the applicator pin 10 contacts the circumferential surface of the roller 14. It can be applied to the printed circuit board 4.

As described above, in the present invention, the amount of adhesive that adheres to the application pin is stable, and the amount of stringiness is extremely small, making it possible to apply the adhesive to the desired location on the printed circuit board. The application pin can selectively contact the outer circumferential surface of the roller and the groove, so when the amount of adhesive required is small, it can be applied to the outer circumference of the roller. When a large amount of adhesive is applied to a surface, the amount of adhesive can be controlled by touching the applicator pin to the groove, and the amount of adhesive applied can be controlled according to the size of the object to be adhered. can be easily performed. Furthermore, since the adhesive held by the roller is attached to the applicator pin, it is not affected by fluctuations in the liquid level of the adhesive. Furthermore, since the required amount is applied one by one to the required location, it is easy to change the product type.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a mounting machine using an embodiment of the present invention, FIG. 2 is a perspective view of the same as above, FIG. 3 is a front view of a roller, FIG. 4 is an enlarged front view of a coating pin, and
The figure is a front view showing the state of the adhesive on the printed circuit board, and FIGS. 6 and 7 are front views showing the state where electronic components are bonded. FIG. 6 is a front view showing the state of the adhesive on the printed circuit board. , FIG. 7 shows the conventional case. 4 is a printed circuit board, 7 is an adhesive supply unit,
10 is an applicator pin, 11 is a case, 14 is a roller, 16 is a doctor knife, and 20 is an adhesive.

Claims (1)

[Claims] 1 The lower part of a roller that is driven to rotate around a substantially horizontal axis is housed in a case that stores adhesive, and an adhesive supply unit that has a doctor knife facing the circumferential surface of the roller with a gap in between; It consists of an applicator pin whose tip touches the circumferential surface.
An adhesive application device characterized in that the roller is provided with a groove covering the entire circumference on its outer peripheral surface, and the application pin is able to selectively come into contact with the outer peripheral surface of the roller and the groove.