JPH07115173B2 - Cream solder applicator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for applying a fixed amount of cream solder used when surface mounting an electronic component on a printed circuit board.

(Prior Art) When surface mounting an electronic component on a printed circuit board,
BACKGROUND ART Cream solder is applied to a pattern on a printed circuit board formed in accordance with a lead arrangement of an electronic component, and the cream solder is heated and melted while the electronic component is placed on the pattern.

In this case, if the lead-to-lead spacing is extremely narrow, around 0.5 mm, such as in flat-packed ICs, if the amount of cream solder applied is too large, the leads will short-circuit by bridging the leads. If the amount is too small, poor connection may occur, so it is necessary to accurately control the coating amount.

Therefore, as shown in FIG. 4, a mask plate M, which is generally a plate material having a certain thickness and a through hole H formed in accordance with the lead pattern P, is overlaid on the printed circuit board K (see FIG. I), squeegee S cream cream R from above
Has been applied (II). According to this, it becomes possible to apply a certain amount of cream solder R ′ depending on the area and thickness of the through hole H of the mask plate M (II
I), because extra cream solder R ″ (II) is attached to the mask plate M and is wasted due to the fact that a large amount of cream solder is prepared at the time of application. Even if solder is collected, it is exposed to air,
Since the dust on the surface of the mask plate is adsorbed, there is a problem that deterioration is likely to occur.

In order to solve such a problem, there is also an apparatus for quantitatively applying each pattern point by using a dispenser such as a syringe, but there is a problem that the application takes time and labor.

(Purpose) The present invention has been made in view of such a problem, and an object of the present invention is to discharge only a necessary and sufficient amount of cream solder from a storage container and apply it at one time according to a pattern. It is to provide a device capable of doing.

(Summary of the Invention) That is, a feature of the present invention is that a discharge port matched with a circuit pattern is formed at the other end of a cylinder member into which a piston member that is axially advanced and retracted by an external operation is fitted The elastic member is attached in the vicinity of the discharge port so as to slightly project from the tip of the discharge port.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 is a cylinder forming a container for cream solder, and a piston 2 which is hermetically fitted into the cylinder 1 at one end thereof.
A lid member 4 formed around a screw hole 4a to be screwed with a screw 3 fixed to is detachably attached, and at the other end, discharge ports 6, 6, 6, which match the lead pattern of the circuit board,
6 is formed. The discharge port 6 is formed by forming a rectangular through hole in the outer peripheral portion of the substrate 7 in accordance with the pattern to be applied, as shown in FIG. A non-slip plate 8 such as a rubber plate is projected and fixed so as to secure the coating thickness d from the tip.

In the figure, reference numeral 5 is a knob fixed to a screw, 10 is an air vent, and 11 is an O-ring fitted to the piston 2.

In this embodiment, the cylinder 1 is filled with cream solder R, the piston 2 is inserted, and the knob 5 is rotated until the cream solder is discharged from the discharge ports 6, 6, 6 ,. (Fig. 2I).

At the stage of completing such preparation, the discharge ports 6, 6, 6 ...
When the cylinder 1 is pressed against the board K so that the pattern matches the pattern P on the printed circuit board K, the cylinder 1 comes into contact with the circuit board K through the anti-slip plate 8 and is fixed to the circuit board K without slipping. A constant gap d is formed between the surface of the circuit board and the tip of the discharge port (II).

When the knob is rotated in this state, the piston 2
Are discharge ports 6, 6, 6 relatively in the cylinder 1 in the axial direction.
Move to the side and push out the cream solder R in the cylinder 1 (III). As a result, the cream solder R has a shape corresponding to the shape from the discharge ports 6, 6, 6 ...
It is discharged by an amount determined by the amount of rotation of the knob 5, and is applied onto the pattern of the printed circuit board P with a thickness that substantially matches the gap length d (IV).

In this state, when the electronic components to be mounted are arranged according to the pattern of the circuit board and heated, the adjacent two
The cream solder adhered so as to bridge the two lead putters is attracted to the pattern P by the surface tension due to melting and separated, and after the leads and the pattern of the electronic component are wetted, they are fixed during cooling. .

FIG. 3 shows an embodiment of a stand suitable for mounting the above-mentioned applicator, in which a plurality of ridges 21, 21, 21 ... Are provided on the surface of the synthetic resin plate 20. Along with the formation, the concave portion 24 is formed in conformity with the bottom shape of the applicator 23 described above.

According to this embodiment, when not in use, the applicator 23 can be placed in the recess 24 to prevent contact with air as much as possible to prevent deterioration of the cream solder, and at the start of use. The residue can be easily removed by pressing the bottom surface of the applicator 23 against the ridges 21, 21, 21 ...

In this embodiment, the discharge port on each side is made continuous by positively utilizing the separation due to the surface tension of the cream solder at the time of melting, but an independent hole is provided according to the circuit pattern, or a long hole is formed. It is clear that the same effect can be obtained by dividing the same into a plurality of parts.

Further, in this embodiment, the piston is moved in the axial direction by the turning operation of the knob. However, the driving screw may be turned by a trigger mechanism or a push button, and a click that restricts a constant rotation amount By providing the mechanism, the applied amount can be controlled more accurately.

Further, although the knob is manually moved in this embodiment, it is apparent that the same effect can be obtained even if the knob is connected to a power source such as a pulse motor or a pressure air limit. Further, in this embodiment, the screw member is integrally formed with the piston, but the screw member may be rotatably fixed between them, and further, the screw is provided on the outer circumference of the piston and the inner circumference of the cylinder. It is clear that the same effect can be obtained even if the two are relatively rotated.

(Effect) As described above, the discharge port is formed at one end of the cylinder according to the lead pattern of the electronic component, and the piston that moves forward and backward by the screw is provided, so the cream solder is stocked as tightly as possible. On the other hand, not only the cream solder can be reliably supplied by exerting a strong pressure by the screw thread, but also the stroke length can be precisely adjusted and the application amount can be accurately adjusted.

Also, since the anti-slip plate is provided on the bottom so that the surface slightly protrudes from the discharge port, not only can it be securely fixed at a predetermined position on the circuit board at the time of contact, but it can also be formed between the surface and the circuit board surface. The coating thickness can be controlled to a constant value with the constant gap length.

[Brief description of drawings]

1 (a) and (b) are a cross-sectional view and a bottom view of an apparatus showing an embodiment of the present invention, FIG. 2 is an explanatory view showing the operation of the same apparatus, and FIG. 3 is another view of the present invention. A perspective view showing an embodiment,
FIG. 4 and FIG. 4 are explanatory views showing a conventional cream solder applying method. 1 ... Cylinder, 2 ... Piston 3 ... Screw, 4 ... Lid member 6, 6 ... Discharge port, 7 ... Substrate 8 ... Anti-slip plate

Claims (1)

[Claims] 1. A discharge port matching the lead pattern of an electronic component is formed at the other end of a cylinder member into which a piston member that is axially advanced and retracted by an operation from the outside is formed, and slightly from the tip of the discharge port. A cream solder applicator in which an elastic member is attached in the vicinity of the discharge port so as to project.