JP2590613B2 - Local soldering method using light beam etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local soldering method using a non-contact heat source such as a light beam when a small chip component or a component with leads is soldered to a printed circuit board.

[0002]

2. Description of the Related Art Most of the conventional local soldering,
It was performed manually using a soldering iron and thread solder.

[0003]

SUMMARY OF THE INVENTION In order to automate the work of soldering small chip parts and parts with leads to a printed circuit board, a robot uses a soldering iron and a thread solder supply nozzle used in conventional manual soldering. Attempts have been made to automate the local soldering by controlling the position of the soldering iron and the feed of the thread solder by holding it in such a way, but in such a method, as the parts to be soldered become smaller, Parts of the soldering iron move or deform due to contact with the tip, and due to instability of heat conduction due to contact from the tip due to wear and deformation of the tip, uniform quality soldering is performed. Was difficult.

[0004] It is an object of the present invention to solve the above-mentioned problems, to enable automation, to improve the efficiency of the soldering operation, and to provide a method of performing uniform and stable quality soldering.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for detecting a non-contact heat source such as a light beam.
Irradiate the applied cream solder locally at least in two steps
Irradiation is performed continuously with changing energy, and the first irradiation energy
Energy value within the irradiation time.
The solder does not boil and the solder does not melt.
Value of the second irradiation energy
The solder melts within the irradiation time and
Minimum value where the part is covered with molten solder and near the soldered part
Is set between the maximum value that does not burn out the member .

Further, in the heating, the first irradiation energy is set to a maximum value within a range in which the flux in the cream solder does not boil and the solder does not melt within the irradiation time, and the irradiation energy in the subsequent second stage is set. The value is set between the minimum value at which the cream solder melts during the irradiation time and the soldered portion is wetted by the solder and the maximum value at which the nearby members are not burned.

[0007]

According to the above means, the non-contact heat source such as a light beam can accurately control the light energy from the light-emitting lamp by controlling the current supplied to the lamp. Therefore, a non-contact heat source such as a light beam can be applied to the soldering iron without affecting the heating method depending on the wear of the soldering tip or the contact of the soldering tip with the soldered portion, as with a soldering iron. Stable and accurate heating can be performed without any displacement or deformation of the parts due to contact with. In addition, since the cream solder is heated at a desired temperature rising rate without being excessively heated by the multi-stage heating, scattering of the cream solder and generation of solder balls due to the rapid heating can be prevented. Further, by optimizing the heating energy, that is, the irradiation energy, good soldering can be performed without wasting energy and time and without burning the printed circuit board.

[0008]

FIG. 1 is a view showing one embodiment of a local soldering method. FIG. 1 (a) is a plan view and FIG. 1 (b) is a front view. 1 (a) and 1 (b), 1 is a printed board, 2 is a conductor formed on the printed board 1, 3 is a chip component, 4 is cream solder, 5 is a light energy irradiation area, and 6 is irradiation. It is a light beam.

FIG. 2 is a schematic configuration diagram of a light beam generating device. In FIG. 2, reference numeral 7 denotes a light emitting lens, and reference numeral 8 denotes a member to be soldered to which light is radiated. Have been. Reference numeral 9 denotes an optical fiber for guiding light to the exit lens 7, and the exit lens 7 is held at a desired position by a robot.
It has flexibility so that it can be positioned in a posture. 1
Reference numeral 0 denotes a lamp house including a light emitting lamp, a mirror, a shutter, an optical fiber light receiving end, and the like, and a light beam 6 emitted from the light emitting lamp is incident on the optical fiber light receiving end. A power supply 11 supplies power to the lamp house 10.

FIG. 3 shows the relationship between the irradiation energy and the irradiation time of the two-stage irradiation of the present invention, and FIGS. 4 and 5 show the relationship between the irradiation energy and the irradiation time in the single-stage irradiation. . In FIG. 3, W1 is equal to t1 from time t1.
The energy is applied during a time T1 up to 2, and is applied to an irradiation area 5 indicated by a broken line in FIG. W
The value of 1 is set to be equal to or less than the maximum value of the energy at which the flux in the cream solder does not boil and the solder does not melt from time t1 to t2. W2 is set to a value at which heating is performed such that the cream solder melts from time t2 to time t3 and the soldered component is wetted by the solder, and the printed circuit board is not burned. Since the time T1 is set to a value at which most of the volatile components of the flux in the cream solder volatilizes and the solder does not melt, the flux in the cream solder can be rapidly heated with a large energy W2 after time t2. Does not boil, so that there is no scattering of the cream solder and no solder balls are generated. If the value of W2 is increased, the time T2 can be reduced. However, if the value is too large, the cream solder is melted and the surface of the nearby printed circuit board is burnt out until the soldered portion is completely wetted by the solder. Must be set to a value that does not cause burnout.

On the other hand, as shown in FIG. 4, when heating is performed in one step from the beginning with energy W3 larger than W1, the time T3 required for melting the cream solder and causing the soldered portion to be wetted by the solder is shown in FIG. Although it is smaller than T1 + T2, the flux in the cream solder boils and solder balls are easily generated, and good soldering is not performed.

When the value of W4 is set to be substantially equal to or smaller than W1 as shown in FIG. 5, the time T4 required for soldering becomes too long, or the solder does not melt and the soldering itself cannot be performed.

As described above, since a non-contact heat source such as a light beam is used, variations in contact heat conduction due to abrasion deformation of the soldering tip in a soldering iron system and a problem due to contact of the soldering iron tip. There is no displacement or deformation of parts,
Further, since ideal heat input control is performed by the two-stage heating, and uniform high-quality soldering without generation of solder balls is possible, automation of soldering can be easily realized.

That is, as described above, the output lens 7 connected to the lamp house 10 of the light source and the optical fiber 9 is mounted on the robot, and a plurality of portions to be soldered are sequentially heated by the above-described method, whereby local soldering is performed. Automation can be realized. In addition, the member 8 to be soldered is mounted on the XY table, and the member to be soldered is moved by the XY table under the fixed exit lens 7 to sequentially move a plurality of soldered portions under the exit lens 7. However, automatic soldering can also be performed by performing irradiation.

[0015]

As is apparent from the above description, according to the present invention, by using a non-contact heat source such as a light beam , abrasion deformation of a soldering tip such as soldering of a soldering iron method and a soldering iron tip can be achieved. To ensure stable soldering by preventing variations in contact heat conduction due to contact with the parts to be soldered and the displacement and deformation of parts due to contact with the soldering iron.
Can be. In addition, since the cream solder is heated at a desired temperature rising rate without being excessively heated by multi-stage heating, it is possible to prevent the cream solder from scattering or generating solder balls due to the rapid heating . Furthermore, by optimizing the heating energy or radiation energy, local areas of the substrate
Since only the temperature can be raised and soldering can be done in a short time,
No waste of energy and time, and printed circuit boards
Not only the parts of the soldered part but also the parts other than the soldered part
The product can be prevented from being burnt and good soldering can be performed , and local soldering can be easily automated.
Wear.

[Brief description of the drawings]

FIG. 1A is a plan view of one embodiment to which a local soldering method of the present invention is applied, and FIG. 1B is a front view of the same embodiment.

FIG. 2 is a configuration diagram showing an example of an apparatus for realizing the local soldering method of the present invention.

FIG. 3 is a diagram showing a heating pattern according to the present invention.

FIG. 4 is a diagram showing an example of a one-step heating pattern.

FIG. 5 is a diagram showing another one-step heating pattern.

[Explanation of symbols]

 4 cream solder 6 light beam

Continuation of front page (56) References JP-A-63-160297 (JP, A) JP-A-1-262069 (JP, A) JP-A-1-225195 (JP, A)

Claims (1)

(57) [Claims] 1. A by changing the irradiation energy in at least two stages from the non-contact heat source to pre-coated cream solder of a local light beam such as irradiated continuously, cream the value of the start of the irradiation energy, within the irradiation time The flux in the solder does not boil and is set to a substantially maximum value within a range where the solder does not melt. The value of the second irradiation energy is set within the irradiation time so that the solder melts and 3. A method of local soldering using a light beam or the like, wherein the value is set between a minimum value covered with molten solder and a maximum value that does not burn out members near the soldered portion.