JPH06170522A - Optical beam soldering device using jointly gas flow - Google Patents

Abstract

PURPOSE:To prevent the burning in the periphery of a land and the contamina tion of a lens due to the beam irradiation by holding a nozzle blowing gas whose temp. is higher than the room temp. and lower than the burning temp. onto a part to be soldered with a holding mechanism. CONSTITUTION:The temp. of the gas flow 5 blown from a gas nozzle 4 is made to be higher than the room temp. and lower than the burning temp. of a solder resist film on a board surface, and for example, in the case of using a glass epoxy board 3b, the suitable range of the gas temp. is made at 100-200 deg.C. The gas nozzle 4 is held with a gas nozzle holding tool 8 so as to blow the gas in the constant angle theta to a guide tube 10 of a thread solder 9. Then the optical beam irradiates in the beam irradiating range 6 larger than the land 3c and the board part is cooled in the gas flow blowing range 7 larger than the range 6. Further, the contamination of the lens caused by fume and the scattering of flux generated from the soldering part is blown off by blowing the gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic local soldering of leaded parts, connectors, etc. to a printed circuit board, and automatic electronic soldering of electronic devices and electronic parts for automatic local soldering in the manufacturing process of electronic parts. The present invention relates to a gas flow combined light beam soldering device used in the field of soldering.

[0002]

2. Description of the Related Art Conventionally, as a means for automating local soldering, there is a method by a "soldering iron robot" in which a trowel is used by a robot, and a cream solder or a thread solder which is heated non-contact by light energy. There was a "light beam" method for automatic soldering.

[0003]

However, when a soldering iron robot is used, the iron contacts the part to be soldered and heats it. Therefore, the heating method is uniform depending on the surface condition and contact condition of the soldering iron. Not only that, but it had the drawback of being stable and difficult to automate. On the other hand, the light beam makes it easier to control the light irradiation energy by irradiating the soldered part with the light energy through the optical fiber and the lens, limiting the light irradiation range to prevent damage to the adjacent parts, and being small and lightweight. There is an advantage that automation can be facilitated by holding the lens in a robot etc., but when the light irradiation range is projected from the land made of copper foil of the printed board and is irradiated on the solder resist film without copper foil, This solder resist film has a drawback that it is easily burnt out. If the light irradiation energy density is reduced to eliminate this burnout, it will take a long time for soldering, or if fumes or flux generated by soldering adhere to the lens that emits light, There is a problem in that the amount of light energy applied to the soldering portion is reduced due to the dirt, and good soldering cannot be performed.

The present invention solves the above-mentioned conventional problems, and there is no burnout around the land due to the soldering due to light irradiation, the soldering time is short, and the light energy amount is not reduced due to lens contamination. The purpose is to provide a device.

[0005]

In order to achieve the above object, a gas flow combined light beam soldering device of the present invention holds a lens for emitting light energy in a positioning mechanism such as a robot or simply a mechanical holding mechanism. Then, position the lens so that the light near the focal point of the light emitted from the lens irradiates the soldered part, and this soldered part is higher than room temperature, and the soldered part or its vicinity can be burnt out. A nozzle for blowing a gas at a temperature lower than the burning temperature of the material is held by a position calibrating mechanism such as the robot or a simple mechanical holding mechanism.

In the case of using the thread solder, the guide tube of the thread solder to be fed to the portion to be soldered is held by the holding / positioning mechanism of the lens for irradiating light or a simple holding mechanism, and the guide tube into which the thread solder is fed. The gas spray nozzle is attached, and the angle between the guide tube for feeding the solder wire and the gas nozzle is 90 ° or less, preferably 60 ° or less, and this angle can be set at any position with the gaz nozzle centered on the center axis of the guide tube. And

Further, a gas temperature detector is provided in the vicinity of the gas outlet of the gas nozzle to detect the gas temperature, a feedback control device for keeping the outflow gas temperature constant, and means for arbitrarily setting the temperature of the gas are provided. .

In order to reduce the oxidation of the solder and the material in the vicinity thereof, a gas having a relatively low activity such as air or CO ₂ gas or an inert gas such as N ₂ gas or argon gas is used. Then, the gas flow velocity is set to the maximum value in the flow velocity range that does not blow off the molten solder / molten flux or cream solder.

Further, in order to prevent abnormal temperature rise of the gas or heater and the occurrence of defective soldering,
A gas pressure detector or gas flow rate detector is installed in the gas flow path, and when the gas pressure or gas flow rate falls below a certain value, it is equipped with means for stopping heating of the gas and stopping soldering. In order to reliably cool the excessive temperature rise of the solder resist film by the gas, the center of the gas flow that flows out from the gas nozzle is almost the same as the center of the light irradiation to the soldered part and In addition, the gas flow hits a wide range, and the outflow direction of the gas flow is directed to the direction in which the gas flow hits the next soldering point.

[0010]

According to the above structure, the gas acts on the soldered portion both for heating and cooling due to the temperature difference between the gas and the soldered portion. The part to be soldered is at room temperature at the start of light irradiation, and if the gas temperature is set near the melting point of the solder, the gas also serves as a heating means until the part to be soldered rises to the gas temperature. When the soldered portion rises above the gas temperature, the gas has a function of cooling the soldered portion.

The melting point of commonly used solder is 180-
Most of them are about 200 ° C, and the temperature at which the solder resist film coated on the surface of the printed circuit board and the base material thereunder is burnt out in a short time (1 to 3 seconds) is 260 to 350 ° C.
In many cases, the temperature of the gas is 160 ° C, for example.
When the temperature is set to 160 ° C., the temperature of the soldered portion is heated by irradiating the light and blowing the gas to accelerate the temperature rise.
However, when the temperature of the resist film or the like is raised to 160 ° C. or higher due to the irradiation of light, the temperature of the gas to be sprayed becomes relatively low, and the temperature rises relatively easily, and the temperature difference between the resist film and the gas becomes large. As the temperature difference increases, the heat is taken away more effectively and the part is cooled, and the burnout is prevented.

Even if the fume or flux generated from the soldered portion is contaminated by the lens, the fumes or flux can reach the lens by blowing the gas so that the heat exchange between the gas and the soldered portion is improved. Since it is blown by gas, it is almost completely prevented.

[0013]

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

In FIG. 1, 1 is a lens that emits light, and 2 is light that is emitted. Reference numeral 3 is a soldered portion, 3a is a lead, 3b is a substrate, 3c is a land made of copper foil provided on the substrate, and the leads 3a and the land 3c are soldered. 4 is a gas nozzle, 5
Is a gas flow flowing out of the gas nozzle 4. 6 is a light irradiation range, and 7 is a gas flow spraying range, which is wider than the light irradiation range 6. 8 holds the gas nozzle 4,
A fixed angle θ with respect to the guide tube 10 of the solder 9
It is a gas nozzle holding fixture that is fixed by. Reference numeral 11 is a screw for tightening the holding metal fitting 10. When the comb solder is used instead of the thread solder 9, the guide tube 10 is used.
Need not be fixed to the holding metal fitting 8. Reference numeral 12 is a thermocouple that detects the temperature of the gas, and 13 is a temperature detection unit at the tip of the thermocouple 12.

In FIG. 2, 14 is a gas temperature detecting means installed near the gas nozzle, which is composed of a thermocouple 12, and the detected temperature signal is sent to the gas temperature control means 15. The gas temperature control means 15 includes a gas temperature setting means, and controls the gas heating means 16 so that the difference between the set gas temperature and the detected gas temperature becomes small.
The gas heating means 16 is composed of a heating element provided in the gas flow path, and the heated gas is sent to the gas temperature detecting means 14.

Reference numeral 17 denotes a gas flow rate control means, which is composed of a gas flow rate controller and a gas flow meter, and the gas whose flow rate is controlled to be constant is sent to the gas heating means 16. Reference numeral 18 denotes a gas pressure or gas flow rate detecting means, which is composed of a pressure switch that operates when the gas pressure reaches a constant value or a flow rate switch that operates when the gas flow rate reaches a constant value. A signal is sent to the gas heating stopping means 19 and the soldering stopping means 20 when the value becomes equal to or lower than the value, and the heating of the gas and the soldering are stopped. The gas heating stopping means 19 includes at least one electric contact, and opens the contact according to a signal from the gas pressure or the gas flow rate detecting means 18 to stop the supply of electric power to the gas heating means. The solder stop 20 comprises at least one electrical contact,
The signal from the gas pressure or the gas flow rate detection means 18 is received, and the operation of stopping the irradiation of the light of the soldering device is performed by the contact, preventing the abnormal temperature rise of the gas heating means when the gas flow is stopped, and soldering. Prevents defective soldering due to changing conditions.

In the gas flow combined light beam soldering device having the above-described structure, even if the light beam is irradiated in the light irradiation range 6 larger than the land 3c, it is burnt out in the gas flow spraying range 7 larger than that. Since the easy-to-use substrate portion is cooled, it is possible to prevent the substrate from burning.

Further, as for the dirt of the lens due to the scattering of fumes and flux generated from the soldering portion, the fumes and flux reach the lens by blowing the gas so that the heat exchange between the gas and the soldered portion is improved. It is almost completely prevented because it is blown with gas before.

The temperature of the gas to be blown is higher than room temperature and lower than the burning temperature of the solder resist film on the surface of the substrate which is easily burned, and the melting point of the solder, the material of the substrate 3b,
An appropriate gas temperature is determined by the size of the land 3c and the leads 3a, the irradiation density of light energy, and the like. Melting point 183 °
When using C eutectic solder and glass epoxy substrate,
A suitable range of gas temperature is 100-200 ° C, 1
A temperature slightly lower than the melting temperature of the solder at about 40 to 160 ° C. is preferable.

The gas to be used is used for many general soldering in terms of quality and cost, but an inert gas such as nitrogen gas or argon gas and a flux with low activity should be used. Thus, cleaning after soldering can be made unnecessary. Further, by using a gas having a relatively low activity such as the above-mentioned inert gas or CO ₂ gas, it is possible to minimize the oxidation of the solder and the material in the vicinity thereof.

When the flow velocity of the gas is set to the maximum velocity at which the cream solder or the molten solder is not blown off, the heat transfer between the gas and the substrate surface becomes effective. This maximum flow velocity is affected by the shape and size of the soldered portion, but is 5 to 15 m / s.

When a large number of soldering points are adjacent to each other, such as in a connector, when the sprayed gas flows toward the next soldering point, it can be effectively preheated and the soldering time and quality can be improved. Is advantageous in terms of.

[0023]

As is apparent from the above description, according to the present invention, the light irradiation energy is precisely controlled by irradiating the soldered portion with the light energy through the optical fiber and the lens, and the light irradiation range is increased. Limiting the damage to adjacent parts and taking advantage of easy automation by holding a small and lightweight lens in a robot etc., the light irradiation range is beyond the land made of copper foil of the printed circuit board. Even if the solder resist film without the copper foil is irradiated, the solder resist film can be prevented from being burnt. Since this burnout can be prevented, the irradiation energy density of light can be increased and the soldering time can be shortened. Further, by preventing the fumes and fluxes generated by soldering from adhering to the lens that emits light, there is no reduction in the amount of light energy applied to the soldered part due to dirt on the lens, and therefore the solder High-quality automatic soldering can be performed for a long period without the risk of defective soldering.

[Brief description of drawings]

FIG. 1A is a diagram showing a main part of a gas flow combined light beam soldering device according to an embodiment of the present invention. FIG. 1B is a view taken along the line AA of FIG.

FIG. 2 is a block diagram diagram of gas control of a light beam soldering apparatus combined with gas flow according to an embodiment of the present invention.

[Explanation of symbols]

 1 lens 2 light 3a lead 3b substrate 3c land 4 gas nozzle 5 gas flow 6 light irradiation range 7 gas flow spraying range 8 holding metal fitting 9 thread solder 10 guide tube 11 screw 12 thermocouple 13 temperature detector 14 gas temperature detector 15 gas temperature Control means 16 Gas heating means 17 Gas flow rate control means 18 Gas pressure or gas flow rate detection means 19 Gas heating stop means 20 Soldering stop means

Claims (10)

[Claims] 1. A lens for emitting light energy is held by a positioning mechanism such as a robot or simply a mechanical holding mechanism so that light near the focus of light emitted from the lens irradiates a soldered portion. The lens is positioned, and a nozzle that blows a gas at a temperature higher than room temperature and lower than the burning temperature of the burnable material in or near the soldered portion to the soldered portion is used as a positioning mechanism for the robot or the like. A gas flow combined light beam soldering device characterized in that a mechanical holding mechanism holds the nozzle in a fixed positional relationship with the nozzle. 2. The light beam soldering apparatus with a gas flow according to claim 1, further comprising means for arbitrarily setting the temperature of the gas. 3. The light beam soldering apparatus with gas flow according to claim 1, further comprising means for adjusting a position of a nozzle for blowing gas. 4. A nozzle for blowing gas to a guide tube for feeding the solder solder held by a holding / positioning mechanism of a lens for irradiating light or a simple holding mechanism so that a gas can be set at an arbitrary position around its central axis. The light beam soldering device with a gas flow according to claim 1, wherein the light beam soldering device is attached. 5. The gas according to claim 1, wherein an inert gas such as air or CO ₂ gas or the like having a relatively low activity or N ₂ gas or argon gas is used. Flow combined light beam soldering equipment. 6. The light beam soldering device for gas flow combined use according to claim 1, wherein the gas flow rate is set to a maximum value of a flow rate at which molten solder, molten flux or cream solder is not blown off. . 7. A gas temperature detecting means provided near a gas outlet of a gas nozzle, a gas heating means, a gas flow rate controlling means, and an outflowing gas temperature as means for controlling the gas temperature to an arbitrarily set value. Claims 1 to 6 comprising control means
2. A light beam soldering device combined with a gas flow according to any one of 1. 8. A gas pressure detecting means or a gas flow rate detecting means is installed in the gas flow path, and means for stopping the heating of the gas and stopping the soldering when the gas pressure or the gas flow rate falls below a certain value. 8. The method according to claim 1, further comprising:
2. A light beam soldering device combined with a gas flow according to any one of 1. 9. The center of the gas flow flowing out from the gas nozzle substantially coincides with the center of light irradiation to the soldered portion,
The gas flow combined optical beam soldering device according to any one of claims 1 to 8, characterized in that the gas flow is made to hit a wider range than the range to which the light is applied. 10. The gas flow combined light beam soldering according to claim 1, wherein the outflow direction of the gas flow is directed so that the gas flow strikes the point of next soldering. apparatus.