JPH04367758A - Spray type flux coating apparatus - Google Patents

Abstract

PURPOSE:To prevent flux from remaining on the tip of a flux spray nozzle in a spray type flux coating apparatus. CONSTITUTION:A spray controller 4 sprays flux on the basis of the signals showing the width and length of a substrate and the position of a nozzle from a signal delay device 3 and a nozzle reciprocating motion apparatus 5. At the start time of spraying, the spray controller 4 sends a signal starting the injection of air to an air jet part 6 at first and also sends a signal showing the emission of flux to a flux emitting part 7 after a predetermined time is elapsed. At the time of the completion of spraying, contrarily, the spray controller 4 sends a signal stopping the emission of flux to the flux emitting part 7 and subsequently sends a signal stopping the injection of air to the air jet part 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray-type flux coating device, and more particularly to a flux coating device that prevents a flux spray nozzle from being clogged with flux.

0002

2. Description of the Related Art A flux coating device is a device that applies flux to the back side of a printed circuit board with components mounted thereon, which is transported by a conveyor or the like. There are different types of flux application equipment depending on the application method, such as foaming type and spraying type.
The present invention is directed to a spray type flux coating device. A spray type flux coating device is a device that supplies flux and air to a spray type nozzle to atomize and coat the flux. FIG. 5 shows a cross-sectional view of the spray nozzle. The nozzle includes a flux nozzle 23 forming a flux flow path 20 to which flux is supplied, and an air nozzle 22 and a needle 24 formed outside the flux nozzle 23. A flux discharge port 19 is provided at the tip of the flux nozzle 23, and a needle 2 is movable vertically upward and downward relative to the center of the flux discharge port 19.
4 are provided. An air passage 21 is formed between the flux nozzle 23 and the air nozzle 22 to which high-pressure air is supplied from an air compressor (not shown). Further, a portion of the high pressure air is used to control the needle 24. When flux is not sprayed, high-pressure air is not supplied, so the needle 24 moves to a position that blocks the flux discharge port 19, and no flux is sprayed. On the other hand, when spraying flux, the needle 24 moves downward at the same time as the spraying air is supplied, and the flux discharge port 19 is opened.

Conventionally, spray type flux applicators using this type of nozzle have not been able to independently control the supply of flux and air to the nozzle. That is, the supply of air and flux was started and ended at the same time.

0004

[Problems to be Solved by the Invention] In this conventional spray type flux applicator, the supply of air and flux cannot be controlled independently, so when the spray is stopped, flux remains at the tip of the nozzle, and when this dries, The flux discharge port 19 and the air passage 21 become clogged. For this reason,
Stable flux spraying becomes impossible. In addition, there is a problem in that the nozzle tip must be kept clean at all times during daily work, which deteriorates workability. Furthermore, since coarse spray particles are sprayed from the nozzle at the start of flux spraying, uniform flux application is not possible, and there is also the problem that the soldering state of the printed circuit board, which is a post-processing process, is not stable.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the spray type flux applicator of the present invention has a configuration in which flux discharge and air injection can be independently controlled, and also has a structure in which flux discharge and air injection can be controlled independently. Control is performed by shifting the start timing of discharge and air injection and the stop timing of flux discharge and air injection at the end of flux application.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 1 shows a spray type flux applicator with a fixed spray nozzle according to the present invention. In FIG. 1, a board detector 1 is composed of a plurality of transmissive or reflective sensors installed in the width direction of a conveyor (not shown), and each sensor sends a detection signal corresponding to a printed circuit board conveyed by the conveyor. Generates 8. The signal converter 2 generates a substrate presence/absence signal 9 representing the presence or absence of a substrate from the detection signal 8 . Since this substrate presence/absence signal 9 is a signal indicating the presence or absence of a substrate at the position of the substrate detector 1, correction is required to make it a signal representing the presence or absence of a substrate at the position of the spray nozzle. The signal delayer 3 delays the substrate presence signal 9 by the time required for the substrate to reach the spray nozzle position from the detection position of the substrate detector 1, and outputs it as a corrected substrate presence signal 11 indicating the presence or absence of the substrate at the spray nozzle position. do. Spray controller 4
is composed of, for example, a CPU, and the correction board presence/absence signal 1
1, the air injection section 6 and the flux discharge section 7 are controlled by the air supply control signal 13 and the flux supply control signal 14. The air injection section 6 and the flux discharge section 7 supply air and flux to spray nozzles (not shown) according to air and flux supply control signals 13 and 14.

Next, the operation of the spray type flux applicator shown in FIG. 1 will be explained with reference to FIG. 2, which is a flowchart showing the operation of the spray controller 4. If there is no correction board presence/absence signal 11, the printed circuit board is not located at the nozzle position, so the spray controller 4 does not perform any control (step 3).
1). When the correction board presence/absence signal 11 is detected, the air injection unit 6 is first controlled by the air supply control signal 13 to start supplying air to the spray nozzle (step 32). That is, high-pressure air is supplied from a compressor (not shown) to the air flow path of the spray nozzle. After a predetermined time (t), the flux discharge section 7 is controlled by the flux supply control signal 14 to start supplying flux to the spray nozzle (step 33). That is, the needle of the spray nozzle is lowered and the discharge port is opened. At this point, flux application to the printed circuit board begins. When flux application begins, the spray controller 4 detects the disconnection of the correction substrate presence/absence signal 11 (step 34). When the correction substrate presence/absence signal 11 disappears, first, the flux discharge section 7 is controlled by the flux supply control signal 14 to stop the flux supply to the spray nozzle (step 35). After a predetermined time t, the air injection unit 6 is controlled by the air supply control signal 13 to stop the air supply to the spray nozzle (step 36). In this way, clogging of the spray nozzle can be prevented by starting the supply from air when spraying starts and stopping the supply from flux when spraying stops. In addition,
Since the predetermined time t may be sufficiently short with respect to the conveyance speed of the printed circuit board, the delay in starting flux application to the printed circuit board due to the time difference of the predetermined time t is negligible. Moreover, even if there is some unevenness in coating at the edges of the printed circuit board, there are usually no mounted components at the edges of the printed circuit board, and the soldering characteristics are not substantially affected. nevertheless,
If more precise application is required, reduce the delay amount of the signal delay device 3 to hasten the flux discharge start time, and correct the flux discharge stop control using the substrate presence/absence signal 11.
It is better to delay the decision.

FIG. 3 is a block diagram showing a second embodiment of the present invention, which is a spray type flux applicator with a reciprocating spray nozzle. In FIG. 3, the same components as in FIG. 1 are given the same reference numerals. In FIG. 3, signal converter 2
' generates, from the detection signal 8 from the board detector 1, a board presence/absence signal 9 indicating the presence or absence of a printed board, as well as a width signal 10 representing the width of the printed board. The nozzle reciprocating device 5 receives the correction substrate presence/absence signal 11 from the signal delay device 3, controls the reciprocating movement of a spray nozzle (not shown), and generates a nozzle position signal 12 representing the position of the spray nozzle. The spray controller 4' generates an air supply control signal 13 and a flux supply control signal 14 according to the correction board presence/absence signal 11, the width signal 10, and the nozzle position signal 12, and controls the air spray section 6 and the flux discharge section 7. control each.

Next, the operation of the spray type flux applicator shown in FIG. 3 will be explained with reference to FIG. 4, which is an operation flowchart of the spray controller 4'. The board detector 1 generates a printed circuit board detection signal 8, similar to the first embodiment shown in FIG. The signal converter 2' converts the detection signal 8 into a board presence/absence signal 9 indicating the presence or absence of a printed circuit board at the board detection position.
, a width signal 10 representing the width of the printed circuit board is generated. Assuming that the substrate detector 1 is composed of a plurality of sensors as described above, the width of the substrate can be determined based on the number and location of the sensors that generate the detection signal 8. Similar to the first embodiment, the signal delay device 3 delays the substrate presence/absence signal 9 and generates a corrected substrate presence/absence signal 11. When the nozzle reciprocating device 5 detects the correction substrate presence/absence signal 11, it starts reciprocating the spray nozzle. For example, the spray nozzle reciprocates in a direction perpendicular to the direction in which the printed circuit board is conveyed. The nozzle reciprocating device 5 further generates a nozzle position signal 12 indicating the position of the spray nozzle and supplies it to the spray controller 4'. The spray controller 4' controls the supply of air and flux in the following manner in response to the correction substrate presence/absence signal 11, the width signal 10, and the nozzle position signal 12. At the start of operation, the correction board presence/absence signal 11 is detected and waits until it is detected (FIG. 3, step 41). When the presence/absence signal 11 is detected, it is determined from the nozzle position signal 12 and the width signal 10 whether the spray nozzle is within the flux application range (usually the range where the printed circuit board is located) (step 42). As a result, if the spray nozzle is within the application range, the air injection section 6 is first controlled by the air supply control signal 13 to start supplying air to the spray nozzle (step 43). Then, after a predetermined time t, the flux discharge section 7 is controlled by the flux supply control signal 14 to start supplying flux to the spray nozzle (step 44). At this point spraying and application of flux begins. Spraying of flux continues until the spray nozzle leaves the application area (step 45). When the spray nozzle goes out of the application range, the flux discharge part 7 is controlled by the flux supply control signal 14,
Flux supply to the spray nozzle is stopped (step 46). After the predetermined time t, the air injection unit 6 is controlled by the air supply control signal 13 to stop the air supply to the spray nozzle (step 47). At this point, the presence or absence of the correction board presence/absence signal 11 is detected (step 48), and if it is not detected, this indicates that the printed circuit board has passed, and the spraying is then terminated. On the other hand, if the detection continues, steps 42 to 47 are repeated. As a result,
As in the first embodiment, it is possible to realize a spray type flux applicator in which the spray nozzle does not become clogged. Spray control section 4
' can also be realized using a CPU, similar to the spray control section 4 of the first embodiment.

[0011]

[Effects of the Invention] As explained above, the spray type flux applicator of the present invention has a configuration in which flux discharge and air injection are independently controlled by a spray controller, and the timings of air injection and flux discharge are staggered. When starting and stopping spraying, the flux remaining at the tip of the spray nozzle can be blown away with air. This eliminates flux residue at the tip of the spray nozzle, prevents clogging, and eliminates the need for maintenance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

[Figure 2]
Flowchart showing the operation of the spray controller 4 in FIG. 1

[Fig. 3] Block diagram showing a second embodiment of the present invention

[Figure 4]
Flowchart showing the operation of the spray controller 4' in FIG. 3

[Figure 5] Cross-sectional view of the spray nozzle

[Explanation of symbols]

1 Board detector 2,2' Signal converter 3 Signal delay device 4,4' Spray controller 5 Nozzle reciprocating device 6 Air injection part 7 Flux discharge part 8 Detection signal 9 Board presence/absence signal 10 Width signal 11 Correction board presence/absence signal 12 Nozzle position signal 13 Air supply control signal 14 Flux supply control signal 19 Flux discharge port 20 Flux flow path 21 Air flow path 22 Air nozzle 23 Flux nozzle 24 Needle

Claims (2)

[Claims] 1. In a spray type flux application device that applies atomized flux using a spray nozzle to a printed circuit board transported by a transport device, the presence or absence of the printed board at a predetermined position of the transport device is detected. and a printed board detection means for generating a printed board detection signal when the printed board is detected, an air injection means for controlling air supply to the spray nozzle in accordance with an air supply control signal, and a flux supply control. a flux discharge means for controlling flux supply to the spray nozzle in response to a signal; and a spray control means for independently generating the air supply control signal and the flux supply signal in response to the printed board detection signal. A spray type flux application device characterized by comprising: 2. The spray control means generates a first air supply control signal for starting air supply to the spray nozzle after a first predetermined time from the detection of the printed board detection signal; After a second predetermined time after the first predetermined time, a first flux supply control signal is generated to start supplying flux to the spray nozzle, and a third After a predetermined time period, a second flux supply control signal is generated to stop the flux supply to the spray nozzle, and after a fourth predetermined time period after the third predetermined time period, the air supply to the spray nozzle is stopped. 2. The spray type flux applicator according to claim 1, further comprising generating a second air supply control signal for stopping said air supply.