JP2020092245A - Automatic soldering device for surface mounting component - Google Patents

Abstract

To achieve easy soldering of a fine surface mounting component even with a difficult-to-solder size in soldering work using a soldering iron, such as hand work and capable of executing processing with high reproductivity.SOLUTION: By partially irradiating with the light condensed to obtain a temperature suitable for soldering, cream solder or preliminary solder prepared before light irradiation, a component to be processed and a print-circuit board are concurrently heated for soldering, thereby executing processing with high reproductivity, using the system and structure in which heating time and irradiation distance are specified.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for mounting a fine surface mount component on a printed circuit board offline.

Due to the recent trend toward miniaturization of electronic components, electronic components having a length of 1 mm or less have appeared on the market. Mounting of these parts is carried out by soldering in a reflow process after being transported to a designated place by a dedicated chuck of an automatic machine such as a chip mounter, but in the post process and correction process, it is done manually. It is necessary to perform soldering.

A soldering iron is a typical tool for manual soldering, but in general soldering with a soldering iron, apply a small hand at the same time to both the component soldering terminal and the PCB mounting round. It is necessary to heat, melt the solder, and weld both the component and the printed circuit board mounting round with solder.
Therefore, it is necessary to simultaneously replenish the solder while grasping the component with tweezers, holding the component in the designated place, and applying the tip of the soldering iron to both the component and the board at the same time. In this state, the tip of the soldering iron is hard to hit the terminal portion or the round, or the holding of the parts is insufficient, which is a work situation.

Further, since a soldering iron is applied to a component, it is necessary to hold down the component with a force capable of counteracting the applied force. For example, a component called 0603 size has a length of 0.6 mm in the long side direction of the component. The size is small, and the size of the part that can be used for pressing is less than 0.5 mm, and it is difficult to even grasp a part so that the soldering iron can easily hit.
Furthermore, if you try to manually fill and melt the solder while pinching a small size component, holding down the component, and applying the soldering iron, the target area to be machined is tweezers or solder. It is difficult to work while visually checking the situation due to the shadow of the trowel, which makes the work even more difficult.

Alternatively, a soldering iron specialized for chip components has been proposed in the past, but the shape and size of the component are limited, and there is a problem that it is not general-purpose with respect to diversifying component shapes and sizes. ..
Another example is proposed in which heated hot air is blown onto the target component and the printed circuit board to heat and solder the component and the printed circuit board.However, in this method, the target component is very light There is a problem that the components may scatter due to the blown warm air and the mounting may fail.

Actual exploitation 57-065771 58-16968

The problem to be solved is that even for minute parts, both the terminals to which the parts are soldered and the mounting round of the printed circuit board are heated so that the solder can be melted and soldered. However, this is to eliminate the difficulty in workability due to the simultaneous replenishment work of the solder while pressing the part at the designated place and applying the tip of the soldering iron to both the part and the board.
Another point is that by automating, uneven heating time and temperature transmission due to manual work can be eliminated and uniform processing can be repeated.

In the present invention, as a heat source for heating for soldering, a heat source using light obtained by condensing light from a light source such as a halogen lamp in a range of a diameter of 10 mm or less is used.
Pre-solder or cream solder is applied to the mounting round of the printed circuit board where components are to be mounted in advance, and the printed circuit board is placed so that the component to be soldered will come to the specified irradiation position with the component placed at that location. After the installation, the work is started to emit light under the set conditions, and the heat is used to perform soldering. While applying the tip of the soldering iron to both the component and the board, the work of replenishing the solder at the same time can be done by applying cream solder, pre-soldering, placing parts, setting the board. Achieves highly reproducible partial soldering by three independent manual operations and automated light irradiation.

The setting conditions set the irradiation distance and irradiation time, but the irradiation distance sets the height for condensing the light that will be the heat source so that the temperature is suitable for solder welding within a few seconds from the start of irradiation, Allows detailed settings to be set by the irradiation time of light.

According to the present invention, the conventional work of simultaneously performing the work of replenishing the solder while gripping the component, holding the component at a designated place, and applying the tip of the soldering iron to both the component and the board is performed simultaneously. By applying solder or pre-soldering, placing parts, and setting the board, it is possible to simplify each work by simplifying the work individually and automatically turning on the light. Since the irradiation is performed on the workpiece, it is possible to realize a highly reproducible process without depending on the skill of the operator.
In addition, since the light irradiation area is heated in a range, it is less likely that a soldering failure will occur due to non-uniform heating such as heating only the terminals or only the rounds due to damage to the soldering iron. There is an effect, and a centering effect is generated due to the balance of the surface tension of the solder melted by area heating, and there is also an effect of naturally correcting the position of the component.
Further, in the conventional solder, the pattern on the printed circuit board may be damaged due to the mechanical pressing of the soldering iron, but in the present invention, such a mechanical load is eliminated, so that the printed circuit board is It has the effect of reducing the risk of damaging the above pattern.
Note that the present invention has an effect that not only minute components but also surface-mounted components having the same extent as the area of condensed light can be diverted.

Explanatory drawing of the example of a structure of the tool by this invention. (Example 1) Explanatory drawing of the example of a structure of the tool by this invention. (Example 2) Explanatory drawing of the example of a structure of the tool by this invention. (Example 3) Explanatory drawing of the example of a structure of the tool by this invention. (Example 4) Approximation formula obtained from experimental results. Example of characteristic diagram by approximate expression. Explanatory drawing of the characteristic regarding time control. The example of 11 board|substrate height adjustment parts in FIG.

By using light as a heat source for solder welding, while gripping the component accompanying the work with the soldering iron, holding the component in the designated place, and applying the tip of the soldering iron to both the component and the board, In order to be able to perform the work of performing the replenishment work in parallel with three independent steps of applying cream solder or pre-soldering, placing parts, and setting the board, and automated light irradiation. The structure is such that when the substrate to be processed is set, the distance from the light source to the processing target is in the set positional relationship, and the area where the light irradiated by this distance is focused by the lens is approximately 30 mm in diameter. By adopting a structure designed to have a temperature that is sufficient for solder welding within the following range, the temperature around the object to be processed increases with the elapse of irradiation time.

In addition, as a structure that can set the light irradiation time as a setting element, this structure assumes that the distance from the light source to the target component is within the range where the characteristics of temperature fluctuations are approximate to the irradiation time and the irradiation time is set. The lower limit of the irradiation time is the lower limit of the temperature for which the processing is assumed, and the upper limit of the irradiation time for which the setting of the irradiation time is the upper limit of the temperature for which the processing is assumed is the light source. The distance from the workpiece to the processing target is set so that the temperature can be adjusted proportionally with the irradiation time.

In addition, a dimmer that controls the amount of light from the light source and a control unit that can program the operation of these devices are provided, and by starting operation of the user, light is emitted for the set time, which stabilizes the operation. The processing conditions that were set can be reproduced for each processing.

FIG. 1 is an embodiment of the present invention. The light source 1 is a lamp of halogen, xenon, or the like, and has a shape capable of irradiating the condensed light of 4 by fixing the positional relationship with the concave lens 3 by the fixture of 2. In the fixture of 2, the diameter of the area of the condensed light whose distance between the light source of 1 and the component to be processed of 4 is 4 is 10 mm or less when the printed circuit board of 5 is placed, and the irradiation time set in advance is set. It is fixed to the body 10 so that the temperature of the area of the condensed light reaches a temperature at which it can be soldered when it is irradiated with light.

Power is supplied to the dimmer of 8 through the power cord of 9. The dimmer 8 has a function of adjusting the power supply to the light source 1 by PWM or PFM control, and can control the brightness of the light source 1, that is, the amount of heat to be emitted, according to the contents operated by the operation unit 7.
For example, by operating the operation unit of 7, the light source of 1 is caused to emit light by the dimmer of 8 to illuminate the irradiation position of the light with the weak light, and the component of 6 to be processed is placed. It is possible to easily align the processing target component of 6 with the light irradiation position when the printed circuit board of 5 is installed.

The body 10 is fixed to the pedestal 11, and the board height adjusting portion 12 is installed on the pedestal 11 so that the height at which the printed board 5 is placed can be arbitrarily set.
The distance from the light source of 1 to the component to be processed of 6 can be adjusted by the substrate height adjusting unit of 12.
The substrate height adjusting unit 12 does not have to be fixed to the apparatus, and may have a structure as shown in FIG.

FIG. 2 is an example of a case where four fixing portions of the structure shown in FIG. 1 have a function of moving up and down by 13 elevators.
The fixture of 4 is also connected by the connecting portion of the elevator of 13 and the connecting portion of 14, and the fixture of 4 can be moved from the processing position to the storage position of 15 by the lifting operation of the elevator of 13 and the printed board of 5 There is an effect that the fixing tool of 4 does not hinder the loading and unloading of the printed circuit board of 5 when placing the board.
An air cylinder, an electric actuator or the like can be used for the elevator of 13.

FIG. 3 is an example in which the structure shown in FIG. 1 is provided with 16 light shielding plates.
The shading plate 16 has a function of dimming the light emitted during the soldering operation and protecting the eyes of the operator.
The light shielding plate 16 may be opened and closed in association with the operation of the operation unit 7 so as not to obstruct the loading and unloading of the printed circuit board 5.

FIG. 4 is an example in which the structure shown in FIG. 1 is provided with 17 laser pointers.
The seventeen laser pointer is installed so that the eighteen laser light emitted from the seventeen laser pointer is applied to a position corresponding to the light irradiation position.
When installing the printed circuit board of 5 on which the processing target component of 6 is placed, it is easy to align the processing target component of 6 with the irradiation position of the light by adjusting the processing target component of 6 to the point illuminated by the laser beam of 18 can do.

FIG. 5 shows the distance from the light source to the processing target and the irradiation time obtained from the temperature data with respect to the distance from the light source to the processing target and the irradiation time obtained in the experiment by the test apparatus simulating the structure shown in FIG. It is an example of an approximate expression for obtaining the temperature for.
FIG. 6 is an example of a characteristic graph simulated from the approximate expression of FIG. 5. For example, assuming that the distance from the light source to the processing target is 24 mm, the processing temperature is set to an arbitrary temperature in the range of 350° C. to 400° C. When trying to do so, it can be seen that the heating temperature, that is, the irradiation time is adjusted in the range from t1 to t2 to reach an arbitrary temperature.

FIG. 7 is an example of simulating the state of temperature change with respect to heating time obtained from the approximate expression of FIG. 5, and it can be seen that the relationship between temperature and time is not proportional.
However, the temperature from T1 to T2 shown in FIG. 7 is relatively proportional to the heating time from t3 to t4, and such a temperature band that approximates a straight line is suitable for soldering. The distance from the light source to the processing target is set so that the temperature is reached.
By setting this distance, the relationship between the temperature and the heating time, that is, the irradiation time becomes proportional, and the temperature at which the soldering process is performed can be set proportionally by controlling the irradiation time.
Incidentally, it is preferable that the variation amount of the linear approximation band with respect to the straight line is 20% or less.
Further, by providing an upper limit value in the setting range of the irradiation time, it is possible to perform temperature protection so that the processing target does not become an excessive temperature.

FIG. 8 is an example of the 12 board height adjusting section shown in FIG. 1, and has a structure in which the processing target printed board 21 is sandwiched between the fixed side height adjusting section 19 and the working side height adjusting section 20. Has become.
In this case, the height from the bottom surface to the substrate is fixed at an optimally adjusted height h.
In this state, the 12 board height adjusting sections are freely slid on the pedestal 11 shown in FIG. 1 so that the positional relationship between the irradiation position and the processing execution site on the printed circuit board 12 to be processed is optimal. You can match it while keeping the height.

It can be applied to the post-processing and repair processes of printed circuit boards that make extensive use of fine surface-mounted components.

1 Light Source 2 Fixing Tool 3 Concave Lens 4 Condensed Light 5 Printed Circuit Board 6 Parts to be Processed 7 Operation Section 8 Dimmer 9 Power Cord 10 Body 11 Pedestal 12 Board Height Adjusting Section 13 Elevator 14 Connecting Section 15 Storage Position 16 Shading Plate 17 Laser pointer 18 Laser light 19 Fixed side height adjustment unit 20 Working side height adjustment unit 21 Printed circuit board to be processed

Claims (4)

A processing device for soldering surface-mounted components to a printed circuit board, which uses a halogen lamp or xenon lamp as a heat source, a lens, a lens, and a fixture that fixes the positional relationship between the light source and the lens, and is operated by a worker. Control unit, a dimmer that can adjust the amount of light emitted from the light source, a pedestal that supports the entire device, and the installation height of the printed board when setting the printed board on which the parts to be processed are placed It consists of a board height adjustment part, a body that fixes the distance between the component to be processed and the light source placed on the printed board in a fixed positional relationship, and an electric circuit that connects the lamp, dimmer, operating part, etc. By condensing the light generated from the light source on the area where the diameter is 20 mm or less on the printed circuit board on which it is installed, the cream solder or the preliminary solder melted before the light irradiation melts the cream solder or the preliminary solder A device that heats cream solder or preliminary solder and a component to be processed by irradiating light from a light source for a preset time so that the temperature reaches a predetermined temperature to perform soldering processing on a printed circuit board. A fixture that fixes the light source and lens together with a mechanism that moves up and down is provided so that the fixture that fixes the positional relationship between the light source and the lens does not become an obstacle when the printed circuit board on which the parts to be processed are placed in and out of the device. The apparatus of claim 1 adapted to be moved into position. A semi-transparent or opaque plate is provided in an opening through which the light emitted from the light source body puts in and out the printed circuit board on which the component to be processed is placed, so that the light emitted from the light source body can be dimmed or blocked. Equipment. Equipped with a laser pointer installed so as to illuminate the position where the light emitted from the light source illuminates the printed circuit board, and when the printed circuit board on which the processed component is placed is installed, the processed component on the printed circuit board is illuminated. The device of claim 1 adapted for easy alignment.

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