JP3945113B2 - Light beam soldering method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soldering method using a light beam heating device used as a non-contact heating source for soldering electronic components.
[0002]
[Prior art]
A configuration and a soldering method for soldering an electronic component using a light beam heating device and thread solder will be described.
[0003]
FIG. 3 shows the structure of a conventional soldering apparatus, where (a) shows an outline of the apparatus and (b) shows a soldering part. In FIG. 3, 1 is an optical fiber that transmits light energy output from a light emitting source (not shown), 2 is a condensing lens, 3 is a beam emitted from the condensing lens, and 4 is the highest beam energy density. High focus portion, 4a and 4b are defocus portions where the beam energy density is a little away from the just focus, 5 is a solder wire feeder, 6 is a solder wire, 7 is a printed circuit board, 8 is a lead of a discrete component, 9 is a land to be soldered on the printed circuit board, and 10 is a solder fillet formed after soldering.
[0004]
In this conventional soldering method, as a soldering procedure, first, the beam 9 emitted from the condenser lens 2 is used to bring the land 9 of the printed circuit board 7 and the lead 8 of the discrete component to a temperature at which the thread solder 6 melts. Then, the yarn solder 6 is supplied to the land 9 of the printed circuit board 7 by the yarn solder feeder 5 so that the solder fillet 10 is formed. Further, the solder supply of the yarn solder feeding device 5 is stopped and the beam 3 is heated only so as to obtain an optimum solder fillet 10.
[0005]
Note that the diameter of the just focus 4 of the beam 3 is the land 9 of the printed circuit board 7 so that the base material around the land 9 of the printed circuit board 7 is not burned by the beam 3 emitted from the condenser lens 2. It is necessary to make it slightly smaller than the diameter.
[0006]
[Problems to be solved by the invention]
In the conventional method of soldering an electronic component using a light beam heating device and thread solder, the diameter of the just focus 4 of the beam 3 needs to be slightly smaller than the diameter of the land 9 of the printed circuit board 7. Therefore, only the local part of the land 9 is heated and the oxidation is accelerated, so that the spread of the solder at the time of soldering is poor and a problem of soldering quality may occur.
[0007]
In particular, due to the recent increase in environmental awareness, the use of lead-free solder, which excludes lead contained in solder alloys, is increasing, so that the solder melting temperature is from the melting point of conventional lead-containing solder 183 ° C. By raising the lead-free solder to about 220 ° C., it takes a long time to heat only the local area of the land until the thread solder is supplied, and the oxidation is further accelerated.
[0008]
Still, because of lead-free, the land 9 of the printed circuit board 7 also has an increase in the land of the copper level without solder leveler or solder plating. In this case, the oxidation of the land surface becomes more intense and the quality deteriorates. Soldering becomes even more difficult.
[0009]
The present invention is for solving the above-mentioned problems. By using a light beam, the land 9 of the printed circuit board 7 is prevented from being oxidized, the soldering quality is improved, and lead-free soldering can be supported. An object is to provide a soldering method.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the first means of the present invention is necessary for heating the soldering portion and its surroundings in the defocused state of the light beam heater, and for forming the solder leveler. Supply soldering material, create a solder leveler, stop feeding the soldering material, and then heat the soldering part in the just-focused state, and at the same time, the soldering material can be formed to an amount that allows solder fillet formation After the supply is started, the solder fillet is formed by stopping the feeding of the solder material while keeping the just focused state .
[0011]
As a result , when the land of the printed circuit board is a copper cloth (commonly referred to as a red-eye state), the defocus position is used instead of the just focus of the beam emitted from the condenser lens in the heating until the thread solder is supplied. As a result, the periphery of the printed circuit board land is also heated to increase the overall temperature, and the thread solder that can form a solder leveler on the printed circuit board land is supplied by the thread solder feeder to oxidize the printed circuit board land. By completely preventing it, the soldering quality is further improved.
[0012]
The second means of the present invention heats the periphery of the land of the printed circuit board by using the defocus position instead of the just focus of the beam emitted again after supplying the solder material and soldering, By heating the flux residue spreading around the land and removing the excess flux component by heating, the insulation resistance between the conductors after soldering is further improved, and the quality of the entire printed circuit board is improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
By the soldering method, the present invention is the heating to supply the solder wire, even the periphery of printed circuit board lands by using the defocus position rather than just focus of the beam emitted from the condenser lens heating However, by increasing the overall temperature, it has the effect of preventing local oxidation of the land.
[0014]
And, when the land of the printed circuit board is a copper cloth , the present invention uses the defocus position instead of the just focus of the beam emitted from the condenser lens in the heating until supplying the thread solder. In addition to heating the surrounding area of the land to increase the overall temperature, the thread solder feeding device supplies as much solder as the solder leveler can form to the printed circuit board land to completely oxidize the printed circuit board land. It is possible to prevent this, and further, the soldering quality can be improved.
[0015]
Furthermore, the present invention heats the periphery of the land of the printed circuit board by using the defocus position instead of the just focus of the beam emitted again after supplying the thread solder and soldering. It is possible to improve the insulation resistance between the conductors after soldering by heating the flux residue that spreads around and removing excess flux components, thereby improving the quality of the entire printed circuit board. Has an effect.
[0016]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
(Embodiment 1)
FIG. 1 shows a main part of the first embodiment of the present invention. The schematic configuration diagram of the entire apparatus is the same as the schematic configuration diagram of the conventional yarn soldering apparatus shown in FIG.
[0018]
Hereinafter, the operation of the first embodiment will be described. 1A shows the state of the defocus position (4b) of the beam 3, and FIG. 1B shows the state of the just focus position 4 of the beam 3. FIG.
[0019]
First, in FIG. 1A, the position of the beam 3 coming from the condenser lens 2 on the printed circuit board 7 is first set to the defocus position 4b at an energy density that does not burn the printed circuit board 7, and the land of the printed circuit board 7 is set. 9 and the lead 8 of the discrete component are irradiated to heat the entire workpiece to a solderable state.
[0020]
Next, the position at which the beam 3 hits the printed circuit board 7 from the condenser lens 2 in FIG. 1B becomes the position of the just focus 4 of the beam 3 and at the same time, the yarn solder feeding device 5 causes the yarn solder. 6 is supplied to the land 9 of the printed circuit board 7 in such an amount that the solder fillet 10 is formed. Further, the solder supply of the yarn solder feeding device 5 is stopped and the beam 3 is heated only so as to obtain an optimum solder fillet 10.
[0021]
(Embodiment 2)
Next, FIG. 2 shows a main part of the second embodiment of the present invention. The schematic configuration diagram of the entire apparatus is the same as the schematic configuration diagram of the conventional yarn soldering apparatus shown in FIG.
[0022]
Hereinafter, the operation of the second embodiment will be described. 2A shows the state of the defocus position 4b of the beam 3, and FIG. 2B shows the state of the just focus position 4 of the beam 3. FIG.
[0023]
First, in FIG. 2A, the position of the beam 3 coming from the condenser lens 2 on the printed circuit board 7 is first set to the defocus position 4b at an energy density that does not burn the printed circuit board 7. 9 and the lead 8 of the discrete component are irradiated to heat the entire workpiece to a solderable state.
[0024]
In this state, the yarn solder feeder 5 supplies the solder solder 6 in an amount sufficient to form the solder leveler 11 on the land 9 of the printed circuit board 7 and stops the solder supply of the yarn solder feeder 5.
[0025]
Next, the position of the beam 3 coming from the condenser lens 2 shown in FIG. 2B on the printed circuit board 7 becomes the position of the just focus 4 of the beam 3, and at the same time, the yarn solder feeding device 5 performs yarn soldering. 6 is supplied to the land 9 of the printed circuit board 7 in such an amount that the solder fillet 10 is formed. Further, the solder supply of the yarn solder feeding device 5 is stopped and the beam 3 is heated only so as to obtain an optimum solder fillet 10.
[0026]
(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIG. The schematic configuration diagram of the entire apparatus is the same as the schematic configuration diagram of the conventional yarn soldering apparatus shown in FIG.
[0027]
First, in FIG. 1A, the position of the beam 3 coming from the condenser lens 2 on the printed circuit board 7 is first set to the defocus position 4b at an energy density that does not burn the printed circuit board 7, and the land of the printed circuit board 7 is set. 9 and the lead 8 of the discrete component are irradiated to heat the entire workpiece to a solderable state.
[0028]
Next, the position at which the beam 3 hits the printed circuit board 7 from the condenser lens 2 in FIG. 1B becomes the position of the just focus 4 of the beam 3 and at the same time, the yarn solder feeding device 5 causes the yarn solder. 6 is supplied to the land 9 of the printed circuit board 7 in such an amount that the solder fillet 10 is formed. Furthermore, the solder supply of the yarn solder feeder 5 is stopped so that the optimum solder fillet 10 is obtained. Then, returning to FIG. 1A again, the position where the beam 3 from the condenser lens 2 hits the printed circuit board 7 is first set to the defocus position 4b at an energy density that does not burn the printed circuit board 7, and the printed circuit board 7 The flux 12 spread around the land 9 is heated to remove unnecessary flux components by irradiating the periphery of the land 9 and the lead 8 of the discrete part.
[0029]
【The invention's effect】
As is apparent from the above description , according to the present invention , only the land of the land is heated by heating the entire printed circuit board around the land until the thread solder is supplied as in the conventional method. Since this does not accelerate the oxidation of the solder, it is possible to improve the spread of the solder, and the excellent effect of improving the soldering quality is obtained.
[0030]
Further , according to the present invention , by heating the entire printed circuit board around the land, only the local part of the land is heated and the oxidation of only the land is accelerated until the thread solder is supplied as in the conventional method. Therefore, it is possible not only to improve the spread of solder and improve the soldering quality but also to heat the entire printed circuit board around the land again after forming the solder fillet, so that the printed circuit board around the land Since the excess flux residue that spreads over can be removed by heating, the insulation resistance between the conductors after soldering is further improved, and the quality of the entire printed circuit board is improved.
[Brief description of the drawings]
FIG. 1 is a block diagram of the main part of a soldering apparatus according to Embodiments 1 and 3 of the present invention. FIG. 2 is a block diagram of the main part of a soldering apparatus according to Embodiment 2 of the present invention. Schematic configuration diagram of the soldering device (b) Configuration diagram of the main part of the device [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Condensing lens 3 Beam 4 Just focus 4a Defocus 4b Defocus 5 Yarn solder feeder 6 Yarn solder 7 Printed circuit board 8 Discrete component lead 9 Land 10 Fillet 11 Leveler 12 Flux

Claims (2)

In soldering using a light beam heater that can collect light and heat a certain part, the focus of the light beam heater is first defocused and the soldered part and its surroundings are heated. At the same time, supplying the solder material necessary to form the solder leveler, creating the solder leveler, stopping the feeding of the solder material, and then heating the soldering part at the same time as the just-focused state The soldering method by the light beam which starts supply of the solder material to an amount capable of forming a solder fillet, and then stops the feeding of the solder material in a just-focused state to form a solder fillet . The method of soldering with a light beam according to claim 1, wherein after forming the solder fillet, the soldering portion and its surroundings are heated again in a defocused state, and unnecessary flux residues are removed by light beam heating .

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