KR101229069B1 - Infrared reflow soldering system - Google Patents

Abstract

The IR reflow soldering system of the present invention is a multi-wavelength infrared light while being transported along the transfer line by the edge conveyor (12) installed so that the component-mounted PC (1) is connected from the input end of the workstation 10 to the discharge end By performing the soldering operation, the main work station 10 is a pre-heating zone 20 for emitting a multi-wavelength infrared ray for preheating through the heating unit 60 toward the PC 1 mounted on the upper surface And a reflow zone 30 installed to extend to the next stage of the pre-heating zone 20 and emitting multi-wavelength infrared rays through the heating unit 60 to solder the component to the PC1. The heating unit 60 constituting the pre-heating zone 20 and the reflow zone 30 includes a heater housing 64 disposed so as to face a PCB 1 on which components are mounted; The heater how to face And an infrared external heater 66 that is exposed to 64 and emits multi-wavelength infrared rays for soldering the component to the PC1, wherein the upper heating unit 60A thermal heater 66 is the PCB. (1) It emits multi-wavelength infrared light on the upper surface and the heater 66 of the lower heating unit (60B) row is characterized in that it emits multi-wavelength infrared radiation on the lower surface of the PC (1).

Description

Eye reflow soldering system {Infrared reflow soldering system}

The present invention relates to an eye reflow soldering system, and more particularly, to completely block the generation of voids present in solder balls, solder creams, and the like, and to use the radiation function of a multi-wavelength infrared heater. The aim is to provide an eye reflow soldering system designed to minimize the occurrence of cold solder due to the temperature variation of the standard and to completely solder the main component materials to the PC.

Portable devices such as cell phones, notebooks, electronic notebooks, digital cameras, MP3, navigation, etc. contain soldered PCBs of electronic components such as ICs. In order to mount and fix components on the PCB, a soldering process is indispensable.

Hot air convection reflow ovens, which are currently used by most electronics companies, use air that is significantly lower in both thermal conductivity and ratio in the heat transfer medium. Therefore, it is necessary to supply a large amount of heating air per unit time, requiring high power consumption. It is impossible to compensate for the temperature loss according to the specification of the printed circuit, which is inevitable in the generation of cold solder.

This is because the conventional hot air heating method only conducts and reflects thoroughly, so the preheating of the PCB pad, the PCB inner layer, the inside of the ball grid array (BGA) body, and the solder cream is not sufficient, and the exposed part is exposed. Since the solder is melted from the inside of the solder ball (Void), as well as oxygen and gas in the solder cream 102 is soldered in an isolated state from the outside, it has a large and a large number of voids, due to the contact resistance due to these voids And a circuit malfunction such as disconnection.

Therefore, automotive electronics PCB manufacturers or aerospace, telecommunications, and defense PCB makers, which must withstand various adverse conditions and high heat, adopt a method of sufficiently preheating by increasing the size of the refolw system to reduce such voids. In this case, due to the nature of the solder lead can not be lengthened indefinitely) or using nitrogen gas, but this also can only reduce the void by 20-30% than in hot air heating, so complete void removal Is structurally and theoretically impossible.

The present invention was developed to solve the above problems, an object of the present invention is to radiate heat to penetrate the inside of each material having different absorption wavelengths in a unique multi-wavelength of the preheater and the reflow unit. By using this function, the inside of the parts and the component mounting body as well as the solder balls printed on the PCB and the inside of the solder cream printed on the PCB are heated at the same time, causing a kind of firecracker that melts lead, present inside the solder balls and the solder cream. Unlike the hot air reflow system, which completely blocks the generation of voids and also prevents the generation of cold solder due to the temperature loss according to the part specifications, the hot air reflow system generates cold air with sufficient preheating. Eye reflow soldering to produce printed boards that can be fully soldered with the dual effect of eliminating the occurrence of cold solder Intended to provide a system.

According to the present invention for solving the above problems, the workstation 10 having a transfer line leading from the inlet to the discharge end, and is continuously installed along the transfer line of the workstation 10, the components are mounted on the upper surface It includes an edge conveyor (10) to be transported mounted on the PCB 1, the workstation 10 is a multi-wavelength infrared for preheating through the heating unit 60 toward the PC (1) mounted parts A reflow that emits a multi-wavelength infrared ray through the heating unit 60 to be soldered to the PC1 and is installed so as to be connected to the next stage of the pre-heating zone 20 and the pre-heating zone 20 to emit. The heating unit 60 including the zone 30 and constituting the pre-heating zone 20 and the reflow zone 30 is disposed so as to face the PCB 1 on which the component is mounted. ) And facing the PC (1) It is installed in the heater housing 64 so that the IR reflow soldering system, characterized in that it comprises an infrared external heater 66 for radiating multi-wavelength infrared rays for soldering the component to the PC1 (1). do.

According to the present invention, an eye reflow soldering system having the following effects may be provided.

(1) The radiation function that penetrates the material by inherent multi-wavelength infrared rays and transfers heat to all the electronic parts such as PCB, BGA body, PCB pad, PCB, etc. The perfect soldering effect of eliminating voids inside the solder cream, etc., and eliminating cold soldering parts can be obtained. Various serious problems such as malfunctions are prevented in advance. In other words, due to the generation of multi-wavelength infrared rays in the near-infrared and mid-infrared bands, it penetrates into the inside of the PCB or the electronic component and heats the radiation at the same temperature. You will get a perfect soldering effect that eliminates voids).

(2) High speed control is possible which can be immediately responded to on / off control after heating temperature rises to a certain temperature. That is, since the conventional infrared heater is exposed to an external type and directly radiates infrared rays, it is possible to perform high-speed control that can be immediately responded to during heating temperature on / off control.

(3) Infrared generation of plate type It is manufactured by inserting the coil type infrared heater into the ceramic heater housing made of special material, so that the phenomenon of voids in the solder ball or the solder cream can be more reliably prevented, and furthermore, the reflow system There is an effect that can be properly adjusted to the standard.

(4) While supplying sufficient infrared rays to the area of the component to melt the solder, it is possible to prevent the heat dissipation of the heated components to the surroundings, and at the same time selectively supply infrared rays to the extent that does not damage the PCB. , To prevent damage to the target parts, etc., and because there is no wind pressure acting on the parts, as in the case of heating by hot air, due to parts missing due to flying of light or small and high parts or changing the position of the pad Defects, cold solder due to heat absorption of the nearby metal parts, cold solder due to the heat loss of the heat sink of the source is removed, there is an effect that can be a stable soldering. In addition, it is also possible to produce mixed parts PCBs of insert parts and surface mount devices (SMDs) that cannot be soldered when heated by hot air.

(5) Due to the characteristics of the hot air reflow oven, the part specifications (up to and including 25mm in the upper and lower sides) when heating the PCB must be observed (because each zone must independently maintain the amount, speed, and temperature of the hot air, it must be 25mm or more. If possible, it is impossible to maintain temperature control stably due to interference due to air vortex between the zones), and the IR reflow soldering system of the present invention applies a heat wave heating method of a frequency concept without hot air, It is possible to increase the separation distance between the upper heater and the lower heater of the unit and the workpiece, the PCB, to be larger than before, so that there is no interference between the zones. Even the height standard has the effect of making soldering work perfect and easy.

1 is a front view schematically showing the structure of an eye reflow soldering system of the present invention;
2 is a plan view of FIG. 1
Fig. 3 is a side view of Fig. 1
Figure 4 is a side view schematically showing the structure of the heating unit of the present invention
Figure 5 is a perspective view showing the structure of the heating unit which is the main part of the present invention
Figure 6 is a view showing a comparison between the conventional soldering method and the soldering method by the eye reflow soldering system of the present invention
7 is a view showing a comparison between temperature and time in the conventional soldering method and the soldering method using the present invention
8 is a view schematically showing an arrangement structure of a lower heating unit which is a main part of the present invention;
9 is a view showing a change in the heating temperature of the pre-heating zone and the reflow zone in the soldering system of the present invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is a front view schematically showing the structure of the eye reflow soldering system of the present invention, Figure 2 is a plan view of Figure 1, Figure 3 is a side view of Figure 1, Figure 4 is a structure of the heating unit of the main part of the present invention Figure 5 schematically shows a side view, Figure 5 is a perspective view showing the structure of the heating unit which is the main part of the present invention, Figure 6 is a view showing a comparison between the conventional soldering method and the soldering method by the eye reflow soldering system of the present invention, Figure 7 FIG. 8 is a view illustrating a comparison between temperature and time in a conventional soldering method and a soldering method using the present invention. FIG. 8 is a view schematically showing an arrangement structure of a lower heating unit, which is a main part of the present invention, and FIG. 9 is a soldering method of the present invention. A diagram showing the heating temperature change of the pre-heating zone and the reflow zone in the system. Referring to this, according to the present invention, the edge conveyor 12 supporting the component-mounted PC 1 so as to be properly transported has a work station 10 having a structure in which the outlet is continuously installed along the direction of the outlet from the inlet. 10) is installed in a continuous direction from the inlet to the discharge unit to the pre-heating zone 20 for emitting a multi-wavelength infrared for preheating by the heating unit 60, and following the next stage of the pre-heating zone (20) It is installed so as to include a reflow zone 30 for emitting a multi-wavelength infrared rays through the heating unit 60 to solder the components to the PCB (1).

The work station 10 has a structure having a long rectangular chamber-shaped station body having a transfer space therein, and a box-shaped door that opens and closes an upper end of the station body. A pair of edge conveyors 12 facing each other are installed at both positions of the transfer line of the work station 10, and the PCB is mounted on the pair of edge conveyors 12 with the parts mounted thereon. do. At this time, the edge conveyor 12 has a structure in which the edge pin is coupled to the chain (orbital motion by the drive motor, etc.) in the endless track movement along the discharge direction from the input of the workstation (10). In the edge conveyor 12 having such a structure, the preheating zone 20, the reflow zone 30, and the chiller zone 40 are sequentially disposed along the direction of the discharge portion at the input portion. In addition to the edge conveyor 12, the transfer line of the work station 10 may be installed as long as the transfer means capable of transferring the PCB 1 mounted thereon.

The heating unit 60 constituting the pre-heating zone 20 and the reflow zone 30 of the edge conveyor 12 includes a heater housing 64 disposed to face the PCB 1, and such a heater housing 64. It has an infrared exterior heater 66 which is exposed on the side facing the PC1 of the C) and directly radiates the multi-wavelength infrared rays for soldering the component to the PC1.

The heater housing 64 is manufactured in a substantially rectangular block shape using a ceramic capable of emitting infrared rays, and is installed in a metal case with an open bottom. At this time, the metal case is installed on the horizontal frame of the upright support provided in the pre-heating zone 20 and the reflow zone 30, respectively, the ceramic heater housing 64 embedded in the metal case is the PCB (1) It is arranged to face.

In addition, the heater housing 64 is provided with a concave accommodating groove which is opened downward on the surface facing the PC1, and the infrared external heater 66 is accommodated in the concave accommodating groove of the heater housing 64 and at the same time infrared A part of the exterior heater 66 is exposed to the exterior and disposed so as to face the PC1. In this case, the heater 66 is configured in the form of a coil heater 66 for radiating multi-wavelength infrared rays.

In summary, the heating unit 60 includes a heater housing 64 embedded in a metal case and an infrared external heater 66 installed in a concave accommodating groove formed on a surface facing the PCB 1 of the heater housing 64. The heating unit 60 having such a structure is installed at a position facing up and down the pre-heating zone 20 and the reflow zone 30, and thus, the pre-heating zone 20 and the reflow zone 30. When the parts on which the PCB 1 is mounted pass, the external heater 66 of the upper heating unit 60A and the external heater 66 of the lower heating unit 60B are separated by the upper infrared rays between the parts and the PC 1. The safety glass is provided so that it may be safe from falling of the heater 66 and falling of the PCB or components on the lower infrared heater 66. At this time, the safety glass is made of a heat-resistant glass capable of withstanding a high temperature of indirect heat 800 ℃ or more. The multi-wavelength infrared light emitted directly from the upper and lower sheath heaters 66 can be supplied directly to the PC1 surface through the safety glass.

The present invention is composed of eight zones (16 by vertical heating) using an infrared plate heater 66 (IR plate heater) in which the pre-heating zone 20 generates infrared rays. On the other hand, the reflow zone 30, which is a soldered part, is composed of the same external infrared heater 66 as two (up and down four zones), so that the soldering equipment using the 100% infrared heater 66 is used. to be.

Meanwhile, at least the lower heating unit 60B of the upper and lower heating units 60 includes a plurality of infrared external heaters 66 that are separately heated and driven, and each of the infrared external heaters 66 is a heater housing 64. It is coupled to the concave receiving groove formed on the surface facing the PCB 1 of the, consisting of a plurality of divided heating area partitioned into at least two lower heating unit (60B) by a plurality of the infrared external heater 66 do.

In addition, a chiller zone 40 is further provided at the next stage of the reflow zone 30 to cool the solder soldered to the PC 1. The chiller zone 40 may include a nozzle for injecting cold air toward the PC1 by the cold air device.

According to the present invention having such a configuration, the PCB 1 on which the component is mounted is placed on the edge conveyor 12 and passes through the preheating portion through the input portion of the edge conveyor 12, and the heat of the heater 66 radiated from the preheating portion. By this, the PCB 1 and the mounted parts are preheated to an appropriate temperature without difficulty, and the PCB 1 and the components having passed through this preheating part pass through the reflow zone 30 from the heater 66 of the heating unit 60. The solder is melted by the radiated heat and the component is soldered to the PCB 1 and then properly cooled while passing through the chiller zone 40, thereby soldering the component to the PCB 1 in a continuous process. It can be used for soldering operations such as PCB, PCB pad, and ball grid array (BGA).

At this time, in the present invention, the heater 66 of the heating unit 60, which is a main part, is exposed to the external type so as to face the PCB 1 and the safety glass therebetween, so that the parts are not directly soldered by indirect heat caused by hot air. The components are soldered by radiated multi-wavelength infrared rays, which prevents voids and cold solders, which are the most important defects.

In other words, in the conventional hot air method as shown in (a) of FIG. 3, since only the conduction and reflection of the hot air are made (indicated by the arrows), the PCB pad, the PCB inner layer, the inside of the ball grid array (BGA) body, and the solder cream (102) The internal preheating is not enough, and the solder is melted from the exposed part, so that the oxygen in the solder cream 102 as well as the bubbles inside the solder ball 100 are soldered in an isolated state from the outside. In addition, large and many voids are caused, and these voids cause contact resistance and cause a problem in circuits such as disconnection.

On the contrary, in the present invention, the infrared heater 66 constituting the heating unit 60, which is the main part, is installed to be exposed externally with the safety glass interposed so as to face the PC1, and the dotted arrow in FIG. As indicated by, the radiation function that penetrates the material by inherent multi-wavelength infrared radiation and transfers heat to the PCB (1), BGA body, PCB pads, etc., as well as all the layers inside the solder ball 100 at the same time to provide sufficient preheating By doing so, it is possible to obtain a perfect soldering effect that eliminates voids present in the solder balls 100 and solder cream 102, and the like. It has an advantage of preventing various serious problems such as causing a malfunction.

Manufacturers of automotive electronics PCBs and aerospace, telecommunications, and defense PCB manufacturers that have to withstand a variety of adverse conditions and high temperatures have made various efforts to reduce voids and cold solders. The application is sufficient to meet the needs of those who want to achieve complete soldering without voids and cold solders.

In addition, in the present invention, the heater housing 64, which is the main part, is made of a ceramic material capable of emitting far-infrared rays, but the far-infrared rays which are developed in-house so as to enable radiation of the base material and all material parts necessary for soldering are available. It can be said that a ceramic heater is used.

The present invention of such a structure has the following comparison characteristics compared with the PCB soldering equipment (Hot Air convection Reflow soldering equipment) that is used in the majority of the existing PCB production line.

<Comparison Table> Existing Hot Air Reflow oven Invention Soldering area
Inside
Oxygen residual
(void) The outside of the solder cream and the solder ball (in case of BGA) are melted from the outside, and voids (oxygen bubbles) are present in the soldering area. The perfect preheating causes soldering firecrackers in which each solder ball in the solder cream on the PCB melts all at once, minimizing voids by allowing oxygen bubbles inside the lead to escape naturally. (Wetting and spreading perfection for the adhesion characteristic of the lead,) Solderability With the micro parts (0402: 0.2X0.4mm)
Ultra Large Parts (50X50mm) or BGA
(Ball Grid Array) The temperature variation of soldered parts between parts causes cold soldering in large parts and overheating in very small parts (even if the same temperature is applied to the PCB by hot air, if the parts are large, Absorption causes cold solder due to the loss of temperature applied to the soldering site) Complete preheating ensures that solder temperature variations between very small and very large components are not significant, ensuring complete soldering of all components.
Radiation / Penetration method using pre-heating or soldering zone-specific temperature transfer method. The temperature loss in large parts is not sensitive to IR method.) Consumption Thermal conductivity of 0.0000574
Use Air 4 times more thermal efficiency than air due to direct heating and spinning noise Heating zone: 20 pieces, high noise.
Conveyor: 1
Cooling /: 2 ~ 4
Forced Convection Method No need / no noise.
Left east
Left east
(Natural Convection Method) Equipment battlefield
Of same production 5 ~ 6.5m based on Heating 10 zone:
Due to the characteristics of air, a certain standard space is required, and hot air is forced to convection using 20 motors, thus it is difficult to solder parts with light or large air resistance. Heating 10 zone 3.5m:
It is a natural convection method using multi-wavelength of IR, which does not use a motor and improves thermal efficiency with the Penetration / Radiation function.
Perfect heating possible power 12 ~ 35 Kw / hour 5 ~ 6 Kw / hour Flux
Management

Filter replacement method
No function Automatic cleaning system
Creating an N2 atmosphere in the reflow zone
Super steam device installation features

In the present invention, preheating is first performed through the preheating zone 20 and the reflow zone 30, and the soldering operation is completed in the reflow zone 30. FIG. 8 illustrates heating heat conditions in the pre-heating zone 20 and the reflow zone 30. In the reflow zone 30, the maximum heating temperature is maintained at about 270 ° C. or less, and the chiller portion 40 is shown. After cooling in, it is shown to be maintained at about 70 ℃.

In addition, as shown in FIG. 5, at least the lower heating unit 60B of the heating unit 60 includes a plurality of divided heating regions H1, H2, and H3. In FIG. 5, three divided heating regions ( H1, H2, H3).

Therefore, the heater 66 of the center heating area H2 is turned on for a small PCB operation such as a mobile phone or an MP3, and the heaters of other heating areas H1 and H3 are turned on for a relatively large PCB operation such as a notebook. 66) also turns on (on) as a worker to solve all the difficulties due to the high temperature work, and also has the effect of reducing the amount of power consumption.

On the other hand, Figure 5 is a view showing a comparison of the temperature and time relationship in the conventional soldering method and the soldering method using the present invention, conventionally, as shown in Fig. 5 (a) relatively until the heating temperature rise required for soldering On the other hand, the present invention takes much less time until the heating temperature required for soldering, as shown in FIG.

Due to the characteristics of the hot air reflow oven, the part specifications (up to and including 25mm in the upper and lower sides) when heating the PCB must be observed (each zone must maintain the amount, speed, and temperature of the hot air independently. It is impossible to maintain the temperature control stably due to the interference due to the air vortex between the zones), the IAL reflow soldering system of the present invention is applied to the heat wave heating method of the frequency concept without hot air, the upper side of the heating unit, the main part The separation distance between the heater and the lower heater and the workpiece, the PCB, can be increased more than before. Thus, there is no interference between the zones. Even if the soldering work is perfect and easy to have an effect.

In addition, according to the present invention, while supplying sufficient infrared rays to the region of the component to melt the solder, it is possible to prevent heat dissipation of the heated components in the region of the workpiece around the work component, and at the same time to generate infrared rays that do not damage the PCB Each can be selectively supplied to prevent damage to the target parts, and there is no wind pressure acting on the parts as in the case of heating by hot air. It prevents defects due to missing, and removes cold solder due to heat absorption of nearby metal parts and heat loss of its own heat sink, so it is possible to perform a very stable soldering process. . In addition, it is also possible to produce mixed parts PCBs of insert parts and surface mount devices (SMDs) that could not be soldered when heated by hot air.

The present invention is not limited to the above-described embodiments and the accompanying drawings, and those skilled in the art that various substitutions, modifications, and changes are possible without departing from the technical spirit of the present invention. Will be obvious to you.

1: PC 10: work station
12: work table 20: pre-heating zone
30: reflow zone 40: chiller zone
60: heating unit 64: heater housing
66: infrared external heater

Claims (6)

And a work station 10 configured to perform soldering by radiating multi-wavelength infrared rays toward the PC 1 by the heating unit 60 while transferring the parts 1 mounted thereon, along the transfer line. Station 10 is provided with a transfer line for the transfer of the PC 1 mounted on the upper surface and the pre-heating zone 20 for emitting a multi-wavelength infrared for preheating toward the PC 1 by the heating unit 60 And a reflow zone 30 which is installed to continue to the next stage of the pre-heating zone 20 and emits multi-wavelength infrared rays through the heating unit 60 to solder the component to the PC1. The heater unit constituting the pre-heating zone 20 and the reflow zone 30 may include a heater housing disposed so as to face a work table 12 on which the PC 1 mounted thereon is loaded. 64) and the heater so as to face the PC1. Is exposed to the installation housing (64) includes the external infrared heater 66 for emitting infrared wavelengths for soldering the component to the PCB (1),
The heating unit 60 is composed of an upper heating unit 60A disposed to face the upper surface of the PCB 1 mounted thereon, and a lower heating unit 60b disposed to face the lower surface of the PC1. The upper heating unit 60A heat heater 66 radiates multi-wavelength infrared rays to the upper surface of the PC1, and the heater 66 of the lower heating unit 60B row has multiple wavelengths to the lower surface of the PC1. Configured to emit infrared light,
At least the lower heating unit 60B of the upper heating unit 60A and the lower heating unit 60B constituting the heating unit 60 includes a plurality of infrared external heaters 66 which are separately heated and driven. Each of the infrared external heaters 66 is coupled to a concave receiving groove facing the PCB 1 of the heater housing 64 so that the lower heating unit 60B is connected by the plurality of infrared external heaters 66. Eye reflow soldering system comprising a plurality of divided heating regions (H1, H2, H3) divided into at least two or more. According to claim 1, wherein the heater housing 64 is provided with a recess receiving groove which is opened downward on the surface facing the PCB 1, the infrared exterior heater in the recess receiving groove of the heater housing (64). At the same time as the (66) is installed, a portion of the infrared external heater (66) is exposed to the external type and disposed to face the PCB (1) characterized in that the eye reflow soldering system. delete delete 2. The eye reflow soldering system of claim 1, wherein the heater housing is comprised of ceramic for far-infrared radiation. The eye reflow soldering system according to claim 1, further comprising a chiller zone (40) for cooling the solder having soldered parts to the PC (1) at the next stage of the reflow zone (30).

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