JPH0216855Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is applicable to conductors such as ceramic substrates, glass epoxy substrates, phenol substrates, polyamide substrates, etc., which are the base of electronic components, or rectangular chip parts.
This relates to a soldering furnace for manufacturing electronic components, in which components are mounted on the electrodes of chip coils, flat ICs, etc. via preliminary solder, and then passed through the furnace via a conveyance path to melt and solder the preliminary solder. be.

(Prior art) In an electronic parts manufacturing line, in order to solder other parts to the electrodes of the base, the heated object, on which the parts are mounted on the base via preliminary solder, is passed from the inlet to the outlet of the furnace body. Soldering is carried out by placing the solder on the conveyance path facing the other side and melting the preliminary solder while passing through the furnace body.This soldering furnace has a furnace body equipped with a conveyance path from the inlet to the exit. A conventional heating furnace is used in which a large number of rod-shaped or elongated plate-shaped infrared radiant heaters are arranged in the furnace width direction at required intervals on the ceiling and bottom of the furnace.

(Problem that the invention aims to solve) However, such a heating furnace cannot control the temperature division in the length direction, and as a result, it is not only impossible to achieve uniform heating, but also the temperature at both ends decreases. The effective length of a radiant heater must be larger than the width of the object to be heated, which makes the furnace larger and is uneconomical.Also, when large substrates that serve as bases pass through the furnace body successively, the first substrate Since a large amount of heat is absorbed, a temperature difference occurs between the second and subsequent substrates, and as well as temperature non-uniformity within the substrate, the temperature difference between the substrates becomes large, and the heating characteristics become unstable. Therefore, the present applicant provided a heating section consisting of an infrared heating surface and an air supply device in the upper and lower parts of the furnace body, and separated each heating section into a side heating section on both sides along the furnace side wall and an intermediate heating section. By further dividing this into a preheating zone on the inlet side, a second preheating zone with an air supply device, and a high temperature heating zone with an air supply device on the outlet side, He first devised a soldering furnace that solved these problems, and published Utility Application No. 32272 (1983).
-146569), but even in this earlier application, the second preheating zone is easily affected by the heat of the inlet side preheating zone and the outlet side high temperature heating zone, making temperature control complicated. was left behind.

(Means for Solving the Problems) The present invention was completed with the aim of creating a soldering furnace for manufacturing electronic components that solved the above-mentioned problems, and the components are mounted on the base via preliminary solder. For the manufacture of electronic components, infrared heating surfaces with a large number of infrared radiant heaters arranged vertically and horizontally are installed in the upper and lower parts of the furnace body, which has a conveyance path for transporting heated objects from the inlet to the outlet. In a soldering furnace, each heating surface is formed by a side heating section on both sides along the furnace side wall, an intermediate heating section located between the side heating sections and held at the same temperature as these, and the upper end is connected to the ceiling surface. The furnace is partitioned into a preheating zone on the inlet side, a second preheating zone, and a high temperature heating zone on the outlet side, with an inlet side partition wall and an outlet side partition wall located slightly lower and stretched between the furnace side walls. Furthermore, an air supply device for promoting heating, which has a number of air injection ports arranged on the infrared heating surface above the second preheating zone, is attached to the infrared heating section above the high temperature heating zone. is equipped with an air supply device for promoting heating that supplies less air than the air supply device having a large number of air injection ports, and also connects the upper ends of the inlet side partition wall and the outlet side partition wall with the ceiling surface. The upper space formed in between is characterized by communicating with the outside through an exhaust port provided in the ceiling of the furnace body.

(Function) This kind of soldering furnace for manufacturing electronic parts is
Each infrared radiant heater is energized to heat the inside of the furnace using the upper and lower infrared heating surfaces, and at the same time drive the air supply device for heating aid that is attached only above the second preheating zone and the high temperature heating zone on the exit side. The heating aiding air is ejected from each air injection port, and a group of objects to be heated, in which parts are mounted on the base via pre-soldering, is sent from the entrance side of the conveyance path by a conveyor (not shown), and then from the exit side. A primary preheating is carried out in a preheating zone on the inlet side, in which no temperature difference occurs between the side heating section and the intermediate heating section during exit from the
After secondary preliminary heating is performed in the preheating zone, the preliminary solder is melted in a higher temperature heating zone, and the soldering is completed before being sent to the next process from the exit.

(Embodiment) Next, the present invention will be described in detail with reference to the illustrated embodiment. Reference numeral 1 is a tunnel furnace-like furnace body made of a heat insulating material, etc. A circulating conveyance path 2 such as a net conveyor is provided for transporting an object to be heated, on which parts are mounted via solder, from an inlet 3 with a shield plate to an outlet 4 with a shield plate. 5, 5 are upper and lower infrared heating surfaces provided in the upper and lower parts of the furnace body 1,
The infrared heating surface 5 has a large number of infrared radiant heaters 6, each having an electrothermal resistor embedded in a ceramic board, arranged uniformly in the vertical and horizontal directions. And furnace body 1
Each infrared heating surface 5 is an inlet side bulkhead for preventing thermal interference, which is stretched between the furnace side walls with the upper end positioned slightly below the ceiling surface in order to correspond to the temperature profile necessary for heating the object to be heated. The heating length is divided in the furnace length direction by the partition wall 9 and the exit side partition wall 10 to form a preheating zone 11 on the inlet side, a second preheating zone 12, and a high temperature heating zone 13 on the exit side. 15,1
Reference numeral 6 denotes an exhaust port provided in the ceiling of the furnace body 1 above the inlet side partition wall 9 and the outlet side partition wall 10, and the exhaust ports 15 and 16 are equipped with an exhaust blower, a jet injector, etc. (not shown). Following the forced exhaust mechanism, the space above the inlet-side partition wall 9 and the outlet-side partition wall 10 is communicated with the outside so that solder vapor can be exhausted. Note that the arrangement of the infrared radiant heaters 6 on each infrared heating surface 5 is not particularly limited, but in the illustrated embodiment, the preheating zone 11 on the inlet side is arranged in 3 rows x 5 pieces, and the infrared radiant heaters 6 are arranged at 150°C from room temperature.
℃, and the second preheating zone 12 is arranged in 4 rows x 5 so as to be maintained at a temperature of about 150°C. Next, the high temperature heating zone 13 on the exit side is arranged in 2 rows x 5. Individual pieces are heated up to a maximum of 210 to 240 degrees Celsius here. The infrared heating surface 5 above the second preheating zone 12 is provided with an air supply device 8a for promoting heating, which is provided with a large number of air injection ports 7a. The air supply amount is 1/2 that of the air supply device 8a in which a large number of air injection ports 7b are also provided on the heating surface 5.
An air supply device 8b for promoting heating of about 1/3 is attached. Note that it is preferable that the air injection pressure of the air supply device 8a is set to about 20 to 30 m/s at the injection source because this will prevent the mount component from shifting. Furthermore, each of the infrared heating surfaces 5 is located between the side heating parts 5a, 5a on both sides along the furnace side wall so as to extend in the longitudinal direction of the furnace body 1, and is isothermal with these side heating parts 5a, 5a. intermediate heating section 5 held in
The temperature of each heating section is controlled individually so that the temperature near the furnace side wall inside the furnace does not drop compared to the temperature in the middle. Any means can be used to maintain the temperature of the side heating portions 5a to be equal to the temperature of the intermediate heating 5b, but as in the illustrated embodiment, each side heating portion 5a is connected to the inlet side partition wall 9 and the outlet side partition wall 10. Either partition walls 14 and 14 for preventing thermal interference provided orthogonally parallel to each other are used to partition each heating section so that the temperature can be controlled for each heating section, or an infrared radiant heater is installed in the side heating section 5a where the temperature tends to drop. The temperature may be controlled by, for example, making the watt density of the infrared radiation heater 6 higher than that of the infrared radiation heater 6 in the intermediate heating section 5b. In this embodiment, each infrared heating surface 5 is divided into nine sections by making the partition walls 14, 14 orthogonal to the inlet side partition wall 9 and the exit side partition wall 10, and a plurality of infrared rays in the three sections constituting the intermediate heating section 5b are Heater 6
at least one of them, and side heating parts 5a, 5a.
A plurality of infrared radiant heaters 6 in each of three compartments of
At least one of each of them is equipped with a temperature detection thermocouple on the radiation surface side of which is insulated with a thermoelectric material such as a known chromel-alumel wire, and is used as a controller etc. for temperature setting. Temperature control is now possible as a result of the connection. In addition, it is preferable that the upper and lower heating parts are provided facing each other in the upper and lower directions in order to achieve uniform heating, and the shape of the radiation surface of each infrared radiant heater 6 is not limited to a flat shape but may be curved. It may be.
Furthermore, the air injection ports 7a and 7b are not limited to those provided toward the conveyance path 2,
A counter blow may be used to spray in the direction opposite to the conveyance path 2, or the spray may be directed in the same direction as the conveyance path 2, and the injection angle is not particularly limited as long as it matches the base shape of the object to be heated and the furnace configuration.
The branch pipes of the air supply devices 8a and 8b are connected to a high-pressure blower through valved conduits passing through both side walls of the furnace body 1, and a cooling device 17 such as a Sirotskov fan is attached to the outlet. .
Incidentally, a valve may be provided for each heating region in order to adjust the speed of injection from the air injection ports 7a and 7b according to the properties of the reflow component so as not to cause displacement of the mounted component. Further, each infrared radiant heater 6 in the furnace may have an orifice-shaped air supply port provided in a hollow mounting base having a large number of air injection ports in the radiation surface shell.

With this structure, when the object to be heated placed on the conveyance path 2 is sent into the furnace body 1 through the inlet 3, electric heating resistors are placed on the ceramic plate in the upper and lower parts of the furnace body 1. An infrared heating surface 5 consisting of a large number of infrared radiant heaters 6 embedded in the body is divided into an inlet side preheating zone 11, a second preheating zone 12, and a high temperature heating zone by an inlet side partition wall 9 and an outlet side partition wall 10. 13 and side heating parts 5a, 5a by partition walls 14, 14 along the furnace side wall.
and an intermediate heating section 5b, forming a uniform temperature heating surface without thermal interference between each heating section, so that the object to be heated transferred through the conveyance path 2 can be heated even if it has a large base. Even if the base is heated evenly, there is no difference between the center and both ends, and the large base is evenly heated by the radiant heat of the heater. Moreover, above the second preheating zone 12 and the high-temperature heating zone 13 on the outlet side, a compressed air flow generated from a high-pressure blower is heated by passing through branch pipes installed in the furnace body 1. Moreover, a large number of air injection ports 7a for promoting heating are provided in each branch pipe.
Since hot air is blown onto the surface of the object to be heated from 7b, the surface can be further uniformly heated by heating in combination with the radiant heat of each infrared radiant heater 6 forming a uniform temperature heating surface. If the object to be heated is large, a large amount of heat will be absorbed by the object to be heated at the beginning of the conveyance, and when the second and subsequent objects are transferred into the furnace body 1, the conveyance speed will be fast, so the inside of the furnace will be absorbed. Even if the temperature controller operates to raise the temperature of the heater to maintain a constant temperature, there is a temperature increase loss, so the temperature difference between the heated objects tends to become large. Since the hot air from the air injection ports 7a and 7b mentioned above always hits the base, the temperature difference not only inside the heated object but also between the heated objects becomes small, and the heated object that is continuously conveyed is uniformly heated. Can be heated. Moreover, the air supply device 8a in the second preheating zone 12 is connected to the high temperature heating zone 13 on the exit side.
Since the air supply amount is larger than that of the air supply device 8b located in Temperature control in each zone is made extremely easy.
are stretched with their upper ends positioned slightly below the ceiling surface, and exhaust ports 15 and 16 for forced exhaust are provided directly above the gap between the two, so that solder vapor is absorbed by this exhaust. To discharge smoothly from ports 15 and 16. Furthermore, the atmosphere near the ceiling walls of the preheating zone 11 on the inlet side, the second preheating zone 12 and the high temperature heating zone 13 on the outlet side does not stagnate due to the forced exhaust from the exhaust ports 15 and 16. , together with the thermal interference prevention effect of the inlet side partition wall 9 and the outlet side partition wall 10, the second preheating zone 12 is a highly accurate heater even at a lower temperature than the inlet side preheating zone 11 and the outlet side high temperature heating zone. Temperature control becomes possible.
Now, to give a concrete example of the effect, 380×507×1.6t
(Unit: mm) Glass epoxy plate with heater temperature of 44
The temperature is raised from room temperature to 150℃ in 25 seconds in the preheating zone 11 on the inlet side of ℃, and then held at the same temperature for another 35 seconds in the second preheating zone 12, where the heater temperature is 170℃, until the heater temperature reaches 460℃. °C high temperature heating zone 1
3, where the temperature is rapidly raised to 210-240℃ in 30 seconds and then cooled.
32272 (Utility Model Application Publication No. 62-146569), even if continuous heating is performed using a temperature profile with a faster conveyor speed than the specific effect example described in the specification, in the case of conventional rod-shaped heater heating, the temperature decreases in the peak temperature range. The temperature variation was approximately ±10°C, but with this invention, the temperature variation is ±2°C, and moreover, the temperature variation in the second
It was confirmed that the preheating zone had a flat temperature profile and could be heated uniformly. It should be noted that an air supply device for promoting heating with a smaller air supply amount than the air supply device 8a may be additionally attached to the preheating zone 11 on the inlet side.
In the case where the preheating zone 11 on the inlet side is not provided with an air supply device for promoting heating as in the embodiment, a second It is preferable to use an infrared radiant heater 6 having a higher watt density than the preheating zone 12. . Furthermore, since the air supply device utilizes radiant heat within the furnace, it does not require a separate heat source, resulting in an energy-saving furnace, and the air injection device does not require large equipment, making it economical to install.

(Effects of the invention) As is clear from the above description, the present invention consists of the upper and lower infrared heating surfaces in the furnace body consisting of side heating parts and intermediate heating parts on both sides along the furnace side wall, and an intermediate heating part on the inlet side. It is divided into a preheating zone, a second preheating zone, and a high-temperature heating zone on the outlet side, eliminating the temperature difference between the part near the furnace side wall and the middle part, and the temperature difference from preheating to main heating to cooling. The temperature distribution is divided to maintain the optimum conditions for soldering, and the heating sources of the second preheating zone and the high temperature heating zone are an infrared heating surface consisting of a large number of infrared radiant heaters, and Therefore, it is used in combination with an air injection device for promoting heating that injects heated air, and the air supply device for the second preheating zone has a larger air supply amount than that for the high temperature heating zone on the exit side. Moreover, the upper end is located slightly below the ceiling surface of the furnace body, and the upper space formed directly above the inlet side partition wall and outlet side partition wall stretched between the furnace side walls is exposed to the outside through the exhaust port provided in the furnace body. Since it is designed so that it can be vented through communication, the second heating section and the
It has the advantage of being able to efficiently heat the entire area, including the preheating zone, under accurate temperature control, and is of great practical value as it solves the problems of conventional soldering furnaces for manufacturing electronic components. It is.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention, FIG. 2 is a partially cutaway front view, and FIG. 3 is a view taken along the line A--A in FIG. 1. 1... Furnace body, 2... Conveyance path, 3... Inlet, 4...
...Outlet, 5...Infrared heating surface, 5a...Side heating section, 5b...Intermediate heating section, 6...Infrared radiation heater, 7a, 7b...Air injection port, 8a, 8b...
Air supply device, 9...Inlet side partition, 10...Outlet side partition, 11...Inlet side preheating zone, 12
... second preheating zone, 13 ... high temperature heating zone on the exit side, 15, 16 ... exhaust port.

Claims (1)

[Scope of utility model registration request] A large number of infrared radiant heaters 6 are installed vertically and horizontally in the upper and lower parts of the furnace body 1, which is provided with a conveyance path 2 for transporting the heated object with parts mounted on the base via preliminary solder from the inlet to the outlet. In a soldering furnace for manufacturing electronic components, each heating surface 5 is provided with infrared heating surfaces 5 arranged in a row.
The partition wall 9 on the inlet side and the outlet side are formed by an intermediate heating part 5b which is located between a and 5a and held isothermally with these, and is stretched between the furnace side walls with the upper end located slightly below the ceiling surface. It is divided into a preheating zone 11 on the entrance side, a second preheating zone 12, and a high temperature heating zone 13 on the exit side by a partition wall 10, and furthermore, the infrared rays above the second preheating zone 12 are divided into An air supply device 8a for promoting heating in which a large number of air injection ports 7a are arranged in the heating section 5.
At the same time, on the infrared heating surface 5 above the high-temperature heating zone 13, an air supply device 8b for promoting heating, which has a smaller air supply amount than the air supply device 8a and which is provided with a large number of air injection ports 7b, is attached. death,
Further, the upper space formed between the upper ends of the inlet side partition wall 9 and the outlet side partition wall 10 and the ceiling surface is the furnace body 1.
A soldering furnace for manufacturing electronic parts, characterized in that the furnace is connected to the outside through exhaust ports 15 and 16 provided in the ceiling of the furnace.