JPH037073Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a laser soldering device that uses a laser as a heat source, and in particular a solder feeding device that controls the feeding speed of solder thread to an optimal state in relation to the temperature of the soldering target. Pertains to.

Prior Art A laser beam is used as a heat source for soldering equipment. In a laser soldering device, a laser beam continuously heats a soldering point during soldering, and when the soldering point reaches a predetermined temperature, thread solder is supplied to the soldering point. When this solder thread is supplied to a soldering point, the temperature of the soldering point is temporarily lowered due to the heat absorption of the solder thread. If thread solder is continuously supplied even after the temperature at the soldering point has decreased, thermally good soldering becomes impossible.

Purpose of the invention Therefore, the purpose of the invention is to prevent a temporary drop in the temperature of the soldering point when supplying thread solder while maintaining the heat source of the laser beam almost constant. To automatically perform thermally good soldering despite changes in heat capacity and degree of thermal diffusion.

Therefore, the present invention continuously measures the temperature of the soldering point using a temperature sensor while supplying thread solder to the soldering point, and adjusts the feeding speed of the thread solder according to the temperature change. The temperature of the soldering point and the molten solder surface is controlled proportionally so that the temperature of the soldering point and the molten solder surface is always kept within the target temperature, regardless of changes in heat capacity or degree of heat diffusion.

Configuration of the invention FIG. 1 shows a laser soldering device 1 and
1 shows a solder feeding device 2 of the present invention.

The laser soldering apparatus 1 includes a laser oscillation/controller 3, and sends a laser beam to a condensing irradiator 5 through an optical fiber 4. The condensing irradiator 5 irradiates the soldering points 7 of the printed circuit board 7a and the electronic component 7b while appropriately focusing the laser beam 6.

On the other hand, the solder feeding device 2 includes a temperature sensor 8 for measuring the temperature of the soldering point 7 and the temperature of the molten solder surface, a feeding device 10 for feeding the solder thread 9 toward the soldering point 7, and a laser oscillation device. - In order to comprehensively control the controller 3 and the supply device 10, a main control device 11 such as a computer is provided.

The supplying device 10 stores the solder thread 9 to be supplied, draws out the solder thread 9 while sandwiching it between a pair of feed rollers 12, and supplies the solder thread 9 to the nozzle 13. Note that the position of the tip of the solder wire 9 within the nozzle 13 is detected by a position sensor 14 and sent to the main controller 11 as control information. Then, one feed roller 12
is driven by, for example, a stepping type motor 15. Rotation control of this motor 15 is performed by a drive controller 16. That is, this drive controller 16 is bidirectionally connected to the main control device 11, and is also connected to a rotation detector 17 connected to the motor 15 and a V-F oscillator 18. Note that the temperature sensor 8
-F oscillator 18 as well as main controller 11 .

Effect of the invention The main controller 11 stores a soldering program in a predetermined order in advance, and sequentially executes the following soldering processes based on the soldering program.

First, at the beginning of soldering, the laser oscillation
The controller 3 is operated, and the laser beam 6 with a constant energy is applied to the soldering point 7 by the condensing irradiator 5.
irradiate. As a result, the temperature T at the soldering point 7 gradually increases at a constant gradient as time t passes.

FIG. 2 shows the changes in time t and temperature T. Of course, the gradient of this temperature rise is
It varies depending on the soldering target depending on the heat capacity of the soldering point 7 and the degree of heat diffusion.

When the temperature of the soldering point 7 reaches the target temperature T ₀ , the main controller 11 confirms this with the temperature sensor 8 , gives a start command to the drive controller 16 , and sets the standard for the thread solder 9 . At the same time, commands for the supply rate and amount of supply are given. Therefore, the drive controller 16 first rotates the motor 15 in the feeding direction of the solder thread 9 at a standard feeding speed.
The solder thread 9 is fed out toward the soldering point 7 while being sandwiched between a pair of feed rollers 12. The amount of solder wire 9 supplied at this time is detected by the rotation detector 17 as the amount of rotation of the motor 15, and is sent to the main control device 11 as well as the drive controller 16.

In this way, the thread solder 9 is connected to the soldering point 7.
When the solder thread 9 is fed into the soldering point 7, it melts at the soldering point 7 and temporarily absorbs the heat of the laser beam 6, so the temperature at the soldering point 7 temporarily decreases as shown in Figure 2. to descend. During this time, the temperature sensor 8 is also connected to its soldering point 7.
The surface temperature of the solder wire 9 in a molten state is detected, a voltage signal proportional to the temperature T is generated, and this is sent to the main controller 11 and the V-F oscillator 18 as temperature information. Therefore, the V-F oscillator 18 receives the temperature information, generates a command pulse F with a frequency proportional to the voltage value, and sends this to the drive controller 16. As a result,
The drive controller 16 excites the motor 15 in a predetermined order while distributing the command pulse F, and the motor 15 is driven. That is, as shown in FIG. 3, the frequency of the command pulse F increases proportionally when the temperature is high and decreases when the temperature is low. As a result, the feeding speed of the solder wire 9 becomes faster or slower in proportion to the temperature T of the soldering point 7 and the molten solder surface at that position. Therefore, even though the energy of the laser beam 6 is constant, the temperature T of the soldering point 7 remains within the target temperature range ΔT as shown in FIG. I will do it.

During this time, the rotation amount of the motor 15 is subtracted inside the drive controller 16, so when the predetermined feed amount is reached, the motor 15 automatically stops. At this point, the main controller 11 causes the feed roller 12 to rotate again in the reverse direction, that is, in the direction in which the solder wire 9 is pulled back, by giving a command for the reverse direction to the drive controller 16. Pull it back into the nozzle 13. When the tip of the solder wire 9 is detected by the position sensor 14, the main controller 11 gives a command to the drive controller 16 to stop, and also gives a command to the laser oscillation/controller 3 to stop the oscillation operation. give instructions. In this way, the series of soldering steps for soldering point 7 is completed.

Thereafter, the main controller 11 accurately calculates the actual feed amount of the solder wire 9 by subtracting the amount of rotation in the reverse direction from the amount of rotation in the supply direction of the motor 15, and determines whether the amount of solder is excessive or insufficient. do.

Note that when the temperature of the soldering point 7 becomes extremely lower than the target temperature, the main controller 11 stops the supply of the thread solder 9 by giving a stop command to the drive controller 16 for a certain period of time. Stop temporarily. As a result, the temperature of the soldering point 7 quickly recovers to within the target temperature. At that point, the main controller 11 will start supplying the remaining solder wire 9 again.

Effects of the invention In this invention, even though the energy of the laser beam is constant, the supply speed of the solder thread is automatically controlled by the temperature of the soldering point and the temperature of the molten solder surface. Good soldering can be done automatically. In addition, since the temperature of the soldering point and the molten solder surface is controlled by the amount of solder thread supplied per unit time, that is, the speed, no control is required on the laser oscillator side, and complex control of laser energy is not required. No longer needed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a laser soldering device and a solder feeding device of the present invention, Fig. 2 is a graph of the time-temperature relationship at a soldering point, and Fig. 3 is a graph of the relationship between command pulse frequency and temperature. It is an explanatory diagram. 1... Laser soldering device, 2... Solder feeding device, 3... Laser oscillation/control device, 4...
Optical fiber, 5... Focusing irradiator, 6... Laser beam, 7... Soldering point, 8... Temperature sensor, 9... Thread solder, 10... Supply device, 11...
...Main controller, 12...Feed roller, 13...Nozzle, 14...Position sensor, 15...Motor,
16... Drive controller, 17... Rotation detector, 18
...V-F oscillator.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a laser soldering device that solders electronic components to a printed circuit board, etc. by emitting a laser beam as a heat source while focusing it on the soldering point, the soldering point and the molten solder surface. A nozzle that stores the solder wire to be supplied and accurately supplies the tip to the soldering point, and a position sensor that detects the stopping point of the solder. A supply device that sends out the solder intermittently, on/off control of the laser beam, temperature information from the above temperature sensor is used as input to command the supply speed and supply amount to the above supply device, and when the supply of thread solder is finished, the temperature information from the position sensor is sent out. It consists of a main control device that inputs information and stops the operation of the above-mentioned supply device, and the above-mentioned supply device has the following characteristic components:
A pair of rollers that sandwich and send out the solder thread, a variable speed motor that drives these rollers, a rotation detector that detects the amount of rotation of this motor, and a rotation amount of the motor that detects the amount of rotation of the motor based on commands from the main controller. , a drive controller that controls the rotational speed, and inputs temperature information from a temperature sensor to generate command pulses with a frequency proportional to the temperature.
and a V-F oscillator to send to the drive controller, a solder feeding device that supplies a large number of soldering points each having a different heat capacity and degree of thermal diffusion while automatically adjusting the temperature to a target temperature. (2) The above main control device has a function to calculate the actual amount of solder supplied from the difference between the amount of rotation in the feed direction from the rotation detector and the amount of rotation when pulling the solder wire back to its home position. A solder feeding device according to claim 1 of the patented utility model. (3) The main control device receives temperature information from the temperature sensor as input, and when the frequency of the command pulse falls below a certain limit, stops sending out the command pulse for a predetermined period of time, and when the temperature sensor reaches the predetermined temperature. The solder feeding device according to claim 1, wherein the solder feeding device resumes sending out the command pulse when detecting the solder feeding device.