JPH0234471B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a solder melting device for electronic components, and particularly for melting solder on leads of electronic components soldered to a printed circuit board using hot air without adversely affecting adjacent electronic components. The present invention relates to an apparatus for removing electronic components from printed circuit boards by melting them.

Prior Art Conventionally, a failed electronic component was removed from a printed circuit board by melting the solder on its lead portion with hot air. There was a fatal drawback in that the hot air used in the work would hit the solder of another electronic component adjacent to the electronic component and melt it as well. Furthermore, since the work of melting the solder of the electronic component and the work of removing the electronic component from the printed circuit board are performed separately, there is a drawback that the work efficiency is low. Furthermore, since this device could only be used for electronic components of a specific shape or size, it had the disadvantage that multiple devices having hot air outlets matching the shapes of electronic components of various shapes were required. Furthermore, due to its structure, the flow velocity of the hot air is not uniform throughout, resulting in temperature differences in the hot air, and the solubility of the solder of electronic components becomes uneven depending on the location, making it difficult to remove the electronic components from the printed circuit board. There was a drawback. Furthermore, in the conventional example, the electronic components were not removed in conjunction with the rise of the duct, so melting the solder and removing the electronic components had to be done manually using tweezers or the like. First, there was a drawback that the solder might solidify again during that time.

Furthermore, Japanese Patent Application Laid-Open No. 59-8342 discloses a method and apparatus for removing soldered semiconductor elements, but this conventional example uses an inert gas as a heating medium. First, the structure is completely different from the present invention in that gas is introduced from the center and released to the surroundings.If gas is introduced from the center and released to the surroundings in this way, gas may adhere to the leads around the electronic components. It is impossible to melt the solder that is present. Further, the conventional example is characterized in that the gas is not brought into direct contact with the solder, and the configuration is different from the present invention in this point as well. Furthermore, the conventional example is a technique of leaving 10% of the solder on the board and removing 90% of the solder along with the element, and is a different invention whose purpose, structure, and operation and effect are completely different from the present invention. .

Furthermore, Japanese Patent Application Laid-Open No. 74096/1983 discloses the structure of a hot air nozzle unit for an automatic electronic component removal device, but in this conventional example, the nozzle unit can be easily installed and removed using a single-action chuck that is provided in the work head. The invention is aimed at standardizing the invention, and does not disclose a structure in which hot air is introduced from the periphery and released upward from the center. Therefore, its purpose, structure, and operation and effect are completely different from the claimed invention. It is an invention.

In addition, Japanese Utility Model Application No. 57-166378 discloses an element replacement jig, but in this conventional example, hot air enters from the outer flow path and melts the solder, then enters the inner flow path and rises. Although it is similar to the present invention in that it has a structure in which the present invention has a structure that The disadvantage was that it was difficult.

Purpose The present invention was made to eliminate the drawbacks of the prior art described above, and its purpose is to apply hot air only to the lead portions located around specific electronic components on a printed circuit board. By guiding the hot air to the central part surrounded by the leads and discharging it to the outside while melting the solder in that part, the hot air can prevent the hot air from hitting other electronic parts adjacent to the electronic part. The purpose is to make it possible to melt only the solder of a specific electronic component. Another purpose is to provide this device with a suction mechanism so that when the solder of the electronic component melts, the electronic component can be suctioned and automatically removed from the printed circuit board in conjunction with the rise of the duct. The aim is to improve the efficiency of work. Another purpose is to make the hot air blowing part of this device replaceable, and by replacing it with a hot air blowing part having a hot air blowing outlet of the same shape and size as the electronic parts, it can be used in various shapes. The purpose is to make it applicable to electronic components. Another object of the present invention is to configure the main part of the duct with a main flow path for hot air and a sub flow path outside the main flow path in order to guide hot air to electronic components on a printed circuit board.
and by providing a heater over a predetermined range in the main flow path, the air sent by the fan is rapidly heated to a predetermined temperature, and a portion of the heated hot air is released to the outside via the sub flow path. By doing so, the hot air is guided to the electronic components on the printed circuit board with a uniform flow rate and uniform temperature distribution, so that the solder of the electronic components is melted with uniform solubility in a predetermined time. It is to do so. Another purpose is to provide this device with a duct lifting mechanism so that the hot air blowing part of the duct can be manually moved toward and away from the electronic components on the printed circuit board. This makes it easier to remove the electronic components from the printed circuit board.
Moreover, the next positioning of the printed circuit board is facilitated.

Summary In summary, the present invention provides an apparatus for melting the solder on the leads of electronic components soldered to a printed circuit board with hot air and removing the electronic components from the circuit board, in which a fan of a blower and air blown by the fan are heated. and a duct that guides hot air heated by the heater to the electronic components of the printed circuit board, the duct includes an outer flow path through which the hot air flows downward, and a duct that guides the hot air from the outer flow path to the electronic components of the printed circuit board. A hot air blowing section consisting of an inner flow path through which hot air flowing toward the lead portion of the component flows in, rises, and is discharged to the outside, and a main body provided between the hot air blowing section and the fan. The main body is composed of a main channel that guides the air sent by the fan to the hot air blowing section, and a sub-channel that allows a part of the air flowing through the main channel to escape to the outside. The heater is arranged in the main flow channel over a predetermined range, and the air sent by the fan is rapidly heated to a predetermined temperature by the heater, and the heated hot air is heated to a predetermined temperature. The present invention is characterized in that a portion of the hot air escapes to the outside from the sub-flow path, thereby uniformizing the overall flow velocity of the hot air and thereby uniformizing the temperature distribution of the hot air.

Configuration The present invention will be described below based on embodiments shown in the drawings. In FIGS. 1 to 4, a solder melting apparatus 1 for electronic components includes a base 2, a support 3 provided upright on the base, and a lifting mechanism 4 connected to the support in the vertical direction. The duct 5 is movably supported by the duct 5.

The duct 5 includes an air introduction section 6, a main section 7 that heats the air introduced from the air introduction section, and a hot air blowing section 8 that discharges hot air heated by the main section. An air introduction port 6 is provided on the top surface 6a of the air introduction portion 6.
b is formed, and a support plate 10 is mounted above the air inlet 6b across the support plate 10, and on the support plate is a ring-shaped ring concentric with the air inlet 6b adjacent to the air inlet 6b. An air introduction member 11 is arranged, and a fan 12 is arranged inside thereof. A motor 13 is fixed to the lower surface of the support plate 10, and a rotating shaft 13a of the motor passes through the supporting plate and extends above the supporting plate, and the fan 12 is attached to the rotating shaft at its center. The fan and motor are fixedly connected to the blower 1.
6. The main body 7 of the duct 5 includes a rectangular vertical conduit 9 and a rectangular auxiliary conduit 9a extending laterally from the conduit below the conduit, and an outer conduit 90.
The top of the vertical conduit has a flange 9.
b is formed so that the vertical conduit 9 is connected to the lower end of the air inlet 6 and forms the bottom part 6c of the air inlet.

The main body 7 of the duct 5 further comprises an inner conduit 91 arranged in and in combination with the outer conduit 90 . The inner conduit has a cylindrical vertical conduit 92, the top of which is formed with a rectangular flange 92a, the lower end of which is cut laterally to form a pair of wings 9.
2b is formed. The inner conduit 91 is inserted into the outer conduit 90, and the pair of wings fit into both inner surfaces of the auxiliary conduit 9a of the outer conduit to function as a stopper to prevent the inner conduit from coming out of the outer conduit. I'm starting to do that. In this case, the flange 92a of the inner conduit 91 rests on the flange 9b of the outer conduit 90, with its top opening 92c constricting the top opening 9c of the outer conduit 90.

In this way, the main section 7 of the duct 5 is the outer conduit 90.
and an inner conduit 91, and this double structure has an inner main flow path 20 and an outer sub flow path 21 for the air introduced from the air introduction part 6.
forming a vertical conduit 9 of the outer conduit 90;
It is electrically connected to the outside through a hole 9d formed on one side of the board. The sub-flow path is such that air flows from the upstream side 6d of the air introduction section 6 through the main flow path 20 to the downstream side 23 of the air below the main flow path. It is designed to allow escape to the outside through a road. Furthermore, within the main flow path 20, there is a motor support shaft 1 fixed to the lower end of the motor 13 provided in the air introduction part 6 so as to extend downward concentrically with the rotating shaft 13a of the motor.
4 is inserted to form a heater mounting portion 14a, and a nichrome wire is wound around the heater mounting portion a predetermined number of times over a predetermined range to form a heater 15. Note that the diameter of the heater mounting portion 14a of the heater support shaft 14 is the same as that of the main flow path 20.
, that is, the diameter of the inner conduit 91, so that the air flowing through the main flow path flows close to the heater 15 and the air introduced into the heater rapidly rises to a predetermined temperature. It's getting old.

The hot air blowing part 8 of the duct 5 has an outer wall 8a extending in the vertical direction and an outer wall 8b extending in the horizontal direction to form a vertical part 80 having an air outlet 20 at the upper end and an overall opening 21 at the lower end. An outer wall 8b extending laterally at the upper side of the vertical portion has an opening 22 at its lateral end.
A mounting portion 81 is formed as a protrusion. Further, in the hot air blowing part 8, an inner wall 8c extending in the vertical direction passes through the vertical part 80 and opens at the lower end thereof, and forms an inner flow path 82 for hot air that communicates with the outside via the main flow path 20 at the upper end. , an outer flow path 83 of hot air is formed around the inner flow path and communicates with the opening 22 of the mounting portion 81 projecting laterally, so that the hot air flowing through the outer flow path can be connected to the leads 30 around the electronic component 30.
After it hits the solder 31 of a, it is guided to the center of the electronic component, flows into the inner flow path 82, and is discharged above the center. The hot air blowing section 8 can be removably attached to the auxiliary conduit 9c of the main body 7 by fitting its attachment section 81 into the auxiliary conduit 9c of the main body 7. Therefore, the hot air blowing section 8 can be attached in various ways depending on the shape or size of the electronic component. It is designed so that it can be attached to the main body 7.

A suction mechanism 40 for suctioning the electronic component 30 is provided within the inner flow path 82 of the vertical portion 80 of the hot air blowing section 8 . The suction mechanism includes a rod 40a,
a suspension member 40b fixed to the upper end of the rod;
A magnet 40c is fixed to the lower end of the rod, and the length of the rod is slightly longer than the length of the vertical portion 80 of the hot air blowing portion 8 in the axial direction. Moreover, the suspension member 40b crosses the upper air outlet 20 of the inner flow path 82 of the hot air blowing part 8 without sealing it, and is placed on the upper end of the vertical part 80, and the magnet 40c is connected to the vertical part 80 through the rod 40a. It is suspended at a position slightly below the lower opening 21.

Instead of the suction mechanism 40, another suction mechanism 50 shown in FIG. 5 may be used. The suction mechanism includes a conduit 50a disposed in the inner flow path 82 of the vertical part 80 of the hot air blowing part 8, an air suction type suction cup 50b fixed to the lower end of the conduit, and an inner flow path of the vertical part. Road 82
and a vacuum source 50c such as a vacuum pump provided at the upper end of a conduit 50a projecting upwardly to the outside.
As in the case of the suction mechanism 40, the suction cup 50b is capable of vertical movement along the inner flow path 82 via the conduit 50a, and is adapted to suction or release the electronic component 30 by the operation of the vacuum pump 50c. It's getting old.

Further, the duct 5 is supported by the support body 3 at its air introduction portion 6 via a duct lifting mechanism 4. The duct elevating mechanism 4 includes a slide plate 42 fixed to one side of the air introduction section 6 via a pair of brackets 41, a guide plate 43 fixed to the support 3, a vertical portion 44a and a horizontal portion at the top thereof. a positioning member 44 formed of a portion 44b and fixed to the support body at the vertical portion; one side of the air introduction portion 6 and the slide plate 4;
Block 45 welded and fixed to the inner surface of 2
and a positioning screw 46 that passes through the horizontal portion 44b of the positioning member 44 and is screwed onto the block. The positioning screw has a head 46a, so that by properly screwing the screw into the block 45, the head cooperates with the horizontal part 44b of the positioning member 44, and the lower position of the duct 5 in use is adjusted. It's starting to be decided. Further, a protruding race 42a is formed on the outer surface of the slide plate 42 over the entire length in the longitudinal direction, and the race engages with a guide groove (not shown) formed in the guide plate 43 to guide the duct. 5 can be slid up and down along the support 3 in the directions of arrows A and B. Duct 5 in this case
As described above, the lower position of the duct 5 is determined by the cooperation between the upper surface of the horizontal part 44b of the positioning member 44 and the head 46a of the screw 46, and the upper position of the duct 5 is determined by the cooperation between the lower surface of the horizontal part and the upper end 42b of the slide plate 42. Decisions are now being made through collaboration between the parties. A pair of handles 49 are provided on both sides of the air inlet 6 of the duct for manually moving the duct 5 between the upper and lower positions.
is provided. The duct in this embodiment consists of an air introduction section 6, a main section 7, and a hot air blowout section 8, which are formed at right angles. The hot air may be provided so that the hot air flows downward through the outer flow path, is guided from the lower end to the inner flow path in the center, and is discharged upward.

In Figures 1 to 3 and 6, the base 2
A work plate 25 is provided on the top of the work plate, and on the work plate, a plurality of electronic components 30 are connected to the hot air blowing part 8 of the duct 5, and a printed circuit board 32 to which the lead parts 30a around the electronic parts 30 are fixed with solder 31 is attached to the work plate 25. In this case, one specific electronic component on the printed circuit board is positioned directly below the opening 21 at the lower end of the hot air blowing section.

Furthermore, an electronic control section (not shown) using a microcomputer is provided inside the base 2.
The front panel 26 of the base is provided with an operation section, a display section, and the like. That is, the electronic control unit is powered on by operating the power switch 60, and at the same time a blue indicator lamp 61 lights up to indicate that the power has been switched on, and then the start switch 62 is operated. The electronic control unit then starts repeating a predetermined routine,
At the same time, a red indicator lamp 63 lights up to indicate that the electronic control section has started. Next, when the temperature setting dial 64 is rotated to a desired position, the temperature obtained at that position is digitally displayed on the temperature display section 65, and when the set switch 66 is then operated, the temperature displayed on the temperature display section 65 is electronically controlled. The timer 70 is latched at the
operates, and the temperature display section 65 is displayed on the time display section 71.
The temperature displayed is designed to digitally display the specific time required to melt the solder 31 of the electronic component 30. Also, the count display section 72 of the timer 70
, a counter (not shown) that operates during the melting operation of the solder 31 of the electronic component 30 counts the time displayed on the time display section 71 and displays this digitally. Also, the core section 7 of the duct 5
A temperature sensor (not shown) constituting a part of the electronic control unit is provided inside the auxiliary conduit 9a extending laterally, and detects the temperature of the hot air flowing through the auxiliary conduit. If there is an error in the temperature compared to the temperature displayed on the display section 65, an error signal is sent to a microcomputer in the electronic control section to correct the temperature of the heater 15.

Effects The present invention is configured as described above, and its effects will be explained below. In FIGS. 1 to 3 and 6, first, a hot air blowing section 8 suitable for the shape and size of a specific electronic component 30 on a printed circuit board 32 is selected and attached to the main section 7 of the duct 5. After installation, the screws 46 for positioning the duct elevator 4 are set appropriately, and the uppermost position of the duct 5 shown in FIG. 1 and the lowermost position shown in FIG. Next, a plurality of electronic components 30 each take a printed circuit board 32 with lead portions 30a around it fixed with solder 31, and one particular electronic component is connected to the hot air of the duct 5. The work plate 25 of the base 2 is positioned directly below the opening 21 at the lower end of the blowout part 8.
position on top.

Next, when the power switch 60 of the electronic control section (not shown) by the microcomputer is operated from the off side to the on side, the power is turned on to the electronic control section.
At the same time, the blue indicator lamp 61 lights up to indicate that the electronic control section is powered on. Next, when the start switch 62 is pressed, the electronic control section starts repeating a predetermined routine, and at the same time, the red indicator lamp 63 lights up to indicate that the electronic control section has started. Next, turn the temperature setting dial to any position to specify the temperature, for example 250°C, and this value will be digitally displayed on the temperature display section 65. Next, when you operate the set switch 66 from the OFF side to the ON side, the temperature will be displayed. At the same time, the timer 70 operates and the temperature (250°C) displayed on the temperature display section 65 of the time display section 71 is latched in the electronic control section. The time required for dissolution, ie, the number of seconds, is displayed digitally.

Next, the operator grasps the handle 49 of the duct 5 and moves the duct downward from the upper position shown in FIG. lower it until it touches the In this case, the lower end of the outer wall 8a forming the opening 21 at the lower end of the hot air blowing part 8 of the duct 5 is connected to the lead around the electronic component ₃₀ with a predetermined gap C1 from the upper surface of the printed board 32, as shown in FIG. The lower end of the inner wall 8c of the hot air blowing part 8 surrounds the outer periphery of the part 30a, and the lower end of the inner wall 8c of the hot air blowing part 8 is connected to the lead part 3 of the electronic component 30.
The electronic component 30 is surrounded by a predetermined gap C ₂ along the base of the electronic component 30 from the top surface of the electronic component 30 . Then, the suction mechanism 40 in the hot air blowing section 8 contacts the electronic component with the magnet 40c at its lower end and adsorbs it, and at the same time the rod 40a is lifted upwards, so that the suspension member 40b at the top of the rod is suspended from the hot air blowing section. 8 and away from the hot air outlet 20 to completely open the outlet.

When the duct 5 reaches the predetermined lowermost position shown in FIG. The temperature value displayed on the temperature display section 65 and latched in the electronic control section is sent to the microcomputer, which processes this value and outputs the value via the electronic control section. A current corresponding to the current is applied to the heater in the main section 7 of the duct 5 to heat it. At the same time, a counter (not shown) operates to start counting the value displayed on the time display section 71, and digitally displays this on the count display section 72 until the counted value reaches a predetermined value.

While the counter is counting the predetermined value, the motor 13 rotates to rotate the fan 12, and as shown by arrow E, outside air is supplied to the air inlet 6 of the duct 5.
b is introduced into the air introduction part 6 through the air introduction member 11, and the air is introduced into the air introduction part 6 from the upstream side 6 in the air introduction part.
d at a constant speed and flows into the main channel 20 of the main body 7, where it is rapidly heated to a predetermined temperature by the heater 15. When the heated hot air reaches the downstream side 23 leading to the hot air blowing part 8 of the main channel, the flow velocity on the outside of the flow curved at right angles is high and low pressure, and the flow velocity on the inside is low and pressure is high, so that the flow curves at right angles. The hot air inside the curved flow flows into the sub-flow path 21 as shown by arrow F and escapes to the outside through the hole 9d provided in the outer conduit 9 of the main body 7. As a result, the flow velocity of the hot air is made uniform throughout the downstream side 23, and the temperature distribution is also made uniform.

In this way, the hot air flows into the outer flow path 83 of the hot air blowing part 8 at an overall uniform flow rate, flows downward, and hits the solder 31 of the lead part 30a around the electronic component 30 at a predetermined speed. dissolve. In this case, the hot air flows between the lower end of the hot air blowing section 8 and the printed circuit board 3.
2 leaks to the outside from the small gap C ₁ between the upper surface 32a of the hot air and the upper surface 32a of the hot air, but since the inflow resistance into the inner flow path 82 of the hot air blowing part 8 is significantly lower than the outflow resistance to the outside, the hot air flows through the outer flow path 83. Almost all of the hot air that hits the lead portion 30a around the electronic component 30 is guided to the center of the electronic component, flows into the inner flow path 82, and flows above the center to the hot air outlet 20.
From there, it is discharged to the outside as shown by arrow G. Therefore, this hot air will not leak to the outside from the lower end of the hot air blowing section 8 and melt the solder on the leads of other electronic components adjacent to the specific electronic component 30.

During this time, if for some reason an error occurs in the temperature of the hot air compared to a predetermined set temperature, the temperature sensor in the main section 7 of the duct 5 detects this error and transmits an error signal to the microcomputer in the electronic control section. The microcomputer receives the error signal and operates the electronic control unit to adjust the current to the heater 15 to adjust the temperature of the heater and maintain the hot air at a predetermined temperature.

During this time, when the counter counts a predetermined time, it is reset, and at the same time, the electronic control section stops supplying current to the motor 13 and heater 15.

Therefore, when the operator grasps the handle 49 of the duct 5 and raises the duct through the lifting mechanism 4, the suction mechanism 40 in the hot air blowing part 8 of the duct also rises, and the magnet 40c of the suction mechanism The electronic component 30 is suctioned and removed from the printed circuit board 32. When the duct 5 is moved to the lower position again after removing the electronic component from the magnet, the micro switch operates again and operates the electronic control section to supply current to the motor 13 and heater 15, and the electronic control The section operates the counter of the timer 70 to melt the solder on the lead section of the next electronic component.

Note that when a suction mechanism 50 according to another embodiment shown in FIG. When the duct 5 is lowered and the electronic control unit operates, the electronic control unit operates the motor 13 and the heater 1.
5, the vacuum source 50c of the suction mechanism 50 is operated, and the suction cup 50b is activated via the conduit 50a to suction the electronic component 30 on the printed circuit board 32. When the duct 5 rises, the suction mechanism 50 also rises, and the suction cup 50b removes the electronic component 30 from the printed board 32. and the suction cup 5
When the electronic component is removed from 0b, the vacuum source 50
c stops operating, and at the same time all related parts of the electronic control section are reset.

Effects Since the present invention is configured and operates as described above, hot air is applied only to the lead portion located around a specific electronic component on a printed circuit board, and the hot air is used to melt the solder in that portion. Since the hot air is guided to the central part surrounded by the lead part and discharged to the outside, the hot air does not hit other electronic components adjacent to the electronic component. The effect is that only the solder can be melted. Furthermore, since this device is equipped with an electronic component suction mechanism, it is possible to suction the electronic component and automatically remove it from the printed circuit board once the solder of the electronic component has melted, thereby improving work efficiency. This has the effect of being able to. In addition, since the hot air outlet is replaceable, it can be used for electronic components of various shapes by replacing the hot air outlet with a hot air outlet of the same shape and size as the electronic component. Effects can be obtained. In addition, the main part of the duct is made up of a main flow path for hot air and a sub flow path outside the main flow path to guide the hot air to the electronic components on the printed circuit board, and a heater is provided in the main flow path over a predetermined range. The air sent by the fan is rapidly heated to a predetermined temperature, and a portion of the heated hot air is released to the outside through the sub-flow path, so that the hot air has a uniform flow rate and uniformity throughout. The solder of the electronic component is guided to the electronic component on the printed circuit board with a temperature distribution of , and the solder of the electronic component is melted with uniform solubility in a predetermined time. In addition, a duct lifting/lowering mechanism was installed to allow the hot air blowing part of the duct to be manually moved toward and away from the electronic components on the printed circuit board, so that once the solder melted, the electronic components could be removed from the printed circuit board. The effect is that removal is facilitated and the next positioning of the printed circuit board is facilitated.

[Brief explanation of drawings]

The drawings relate to embodiments of the present invention, in which Fig. 1 is a partial vertical cross-sectional side view of a solder melting device for electronic components, Fig. 2 is a partially broken exploded perspective view of a duct in the direction of - arrow, and Fig. 3 is a lead of an electronic component. FIG. 4 is an exploded partial vertical cross-sectional view showing the main part of the duct and the hot air blowing part, and FIG. 5 is another embodiment of the suction mechanism. A schematic diagram showing the
Figure 6 is a front view of the solder melting device for electronic components, Figure 7
The figure is a cross-sectional view taken along the - arrow in FIG. 6. 1 is a solder melting device for electronic components, 4 is a duct lifting mechanism, 5 is a duct, 7 is a main body, 8 is a hot air blowing section, 12 is a fan, 15 is a heater, 16 is a blower, 30 is an electronic component, 30a is a lead 31 is solder, 32 is a printed circuit board, 40 and 50 are suction mechanisms, 82 is an inner flow path, and 83 is an outer flow path.

Claims (1)

[Claims] 1. An apparatus for removing the electronic component from the circuit board by melting the solder on the lead part of an electronic component soldered to a printed circuit board with hot air, which comprises: a fan of a blower; a heater that heats the air blown by the fan; a duct that guides hot air heated by the above to the electronic components of the printed circuit board, the duct has an outer flow path through which the hot air flows downward, and a duct that directs the hot air toward the lead portion of the electronic component from the outer flow path. The hot air blowing section includes an inner flow path through which the hot air flows in, rises, and is discharged to the outside, and a main section provided between the hot air blowing section and the fan; The main body has a double structure including a main channel that guides the air sent by the fan to the hot air blowing part, and a sub-channel that allows a part of the air flowing through the main channel to escape to the outside, and the heater is disposed in the main flow path over a predetermined range, and the air sent by the fan is rapidly heated to a predetermined temperature by the heater,
Solder melting of electronic components, characterized in that a part of the heated hot air escapes to the outside from the auxiliary flow path, thereby uniformizing the flow velocity of the hot air as a whole and making the temperature distribution of the hot air uniform. Device.