JP2003101212A - Reflow unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein the inside of a heating furnace of a reflow unit is normally 200 to 300 deg.C, a housing covering the reflow unit to eliminate the danger of a worker is desired to be small size and light weight particularly at an upper side for easy handling, but when an interval from the furnace is narrow, its surface temperature is raised, and using of a large quantity of heat insulators inside the housing, to avoid this, raises cost and increases weight. SOLUTION: The reflowing unit comprises the housing section (upper housing 4) of an upper side constituted of a reinforcing fiber plastic. Thus, the surface temperature rise of the housing 3 can be suppressed due to the heat insulation effect of the plastic with the small size and the light weight while its strength is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus for heating a work to be soldered such as a printed wiring board in a heating furnace for soldering.

The inside of the heating furnace of the reflow apparatus is usually 200 ° C.
It is heated to a temperature of about 300 ° C. Therefore, it is necessary to cover the heating furnace with a housing so that the high temperature does not pose a danger to workers.

[0003]

2. Description of the Related Art A reflow apparatus is used for soldering electronic parts on a printed wiring board. The reflow device is a device that heats an area to be soldered to which solder has been supplied in advance or the entire printed wiring board to melt the solder, and solders a circuit pattern formed on the printed wiring board and an electronic component. .

As a method of performing this heating, there are methods such as heating with infrared rays or the like, heating with hot air, heating with steam, heating with heat transfer, and heating using these in combination. Normally, calorific heating is performed in a calorie furnace. Be seen.

The heating temperature is determined mainly by the type of solder used, but is usually about 200 ° C to 300 ° C. As a result, the heating furnace itself becomes hot, and there is a risk of injury such as burns if the human body touches the heating furnace directly.Therefore, the heating furnace is covered with a housing so that the heating furnace is not exposed to the working environment. Has been done.

A metal member such as an iron member is generally used as a material for the casing, and a gap between the heating furnace and the casing is also set to about 20 to 30 cm, and ventilation is performed by exhaust air in this gap. Therefore, the surface temperature of the casing is not excessively increased, and there is no danger to workers. Also,
Insulating member and heat reflecting member etc. are provided inside this iron case,
There is also a reflow device configured so as to suppress an increase in the housing surface temperature.

[0007]

It is desirable that the surface temperature of the housing has an upper limit of about 40 ° C. at the highest, in consideration of safety for workers who work around the reflow device. However, this seems to be a simple and difficult problem. For this reason, in a company with thorough safety management, there is an example in which a shielding wall is further provided outside the housing surface when the temperature of the housing surface on the side where the worker works exceeds a specified value.

On the other hand, since it is necessary to reduce the area occupied by the reflow apparatus, it is necessary to narrow the gap between the heating furnace and the housing in order to reduce the size of the reflow apparatus. However, this has a problem of increasing the surface temperature of the housing.

Further, the surface temperature of the housing is lowered by increasing the amount of ventilation in the gap between the heating furnace and the housing by increasing the forced exhaust flow rate or by providing a large number of heat insulating members inside the housing. However, it requires a special exhaust device or a large amount of heat insulating members, which increases the price of the reflow device and its running cost.

Further, in order to maintain the heating furnace, there is also a reflow device in which the upper part of the housing is formed in a hatch structure so that it can be opened and closed. However, the upper part of the housing and hence the maintenance hatch part are Since it is composed of iron members, it is necessary to make the load capacity of the opening / closing drive actuator that bears its weight and the opening / closing force balancing means such as gas springs and dampers that facilitate opening and closing to be large in proportion to it. is there.

An object of the present invention is to make it possible to maintain the surface temperature of the housing at a lower temperature than ever before, and to make the reflow apparatus compact without increasing the surface temperature of the housing. The purpose of this is to make it possible to reduce the occupied floor area, to make the means for opening and closing the maintenance hatch part smaller and cheaper, and to make the weight of the reflow device lighter.

[0012]

The reflow device of the present invention is characterized in that it is constructed such that a lightweight fiber reinforced plastic having a small thermal conductivity is used in a region where the temperature distribution of the housing is high.

(1) In a reflow apparatus which has a housing for covering a heating furnace and which carries a printed wiring board into the heating furnace by a carrying conveyor for soldering, the housing is above the carrying conveyor. Is a reflow device in which at least the upper casing part of the heating furnace is made of a fiber reinforced plastic member.

In a reflow device for a printed wiring board which is a work to be heated and which is provided with a conveyor for carrying the printed wiring board, heat convection occurs in a casing portion located above the carrying conveyor where the printed wiring board is located. The temperature rises easily and becomes the highest temperature.

On the other hand, fiber reinforced plastic (FRP: f
The iber reinforced plastics is strong, yet lighter than the iron member, and has a small thermal conductivity of 1/100 or less that of the iron member.

Therefore, by using the fiber reinforced plastic in the housing portion above the transport conveyor,
It is possible to suppress the rise of the surface temperature of the housing while maintaining the strength of the housing, and to realize a reflow device having a lower housing surface temperature than ever before, so that a safe working environment can be formed.

Further, it is not necessary to provide a heat insulating member or the like inside the housing or to increase the exhaust air flow rate. Further, the reflow device can be made smaller than the conventional one, and the exclusive floor area can be reduced.

(2) In a reflow apparatus which has a housing for covering a heating furnace and which carries a printed wiring board into the heating furnace by a carrying conveyor for soldering, the housing is above the carrying conveyor. Side housing portion, at least the maintenance hatch portion for opening and closing the upper portion of the heating furnace is formed of a fiber reinforced plastic member, and the maintenance hatch portion is an actuator for driving the opening or closing or an opening and closing force for assisting the opening and closing. It is a reflow apparatus provided with a balancing means.

With this structure, the fiber-reinforced plastic is strong and lightweight, and therefore, the above (1)
In addition to the above action, a small-sized device with a small withstand load is used for fluid pressure actuators and electric motors that open and close the maintenance hatch of the housing, and for opening and closing force balancing means that assist opening and closing of gas springs and dampers. You will be able to use it. Further, the weight of the maintenance hatch portion of the housing is reduced, so that the safety thereof is also improved.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reflow apparatus according to the present invention is
It can be realized in the following example embodiments.

(1) First Embodiment Example-1 A first embodiment example of the reflow soldering apparatus according to the present invention will be described with reference to FIG. 1A and 1B are views for explaining an embodiment example-1 of the reflow apparatus, FIG. 1A is a perspective view showing the whole, and FIG. 1B is a view for explaining a relationship between a heating furnace and a housing. It is the figure which cut | disconnected the housing | casing vertically and was shown.

The reflow apparatus is provided with a casing 3 composed of an upper casing 4 and a lower casing 5 for covering the heating furnace 1. Although not shown, the heating furnace 1 is fixed to a frame, and the housing 3 is usually arranged outside the frame. Further, the inside of the heating furnace 1 is divided into several heating chambers 2, and each heating chamber 2 is provided with, for example, an infrared heater or a hot air supply means corresponding to the heating system, and is provided with a temperature adjusting means. The heating temperature in each heating chamber 2 can be adjusted to a desired value.

The work to be heated, that is, the printed wiring board 6 to be soldered, has solder adhered to the soldering points, and the inside of the heating chamber 2 is moved by the conveyor 7 provided so as to run in the heating chamber 2 in the vertical direction. It is conveyed in the direction of arrow A and heated to a target temperature in each heating chamber 2, that is, heated in a target temperature profile, and the solder is melted and soldering is performed. Although details of the conveyer 7 are not shown, there are many examples of configurations in which both ends of the printed wiring board 6 are held and conveyed by a parallel two-piece conveyer chain.

The inside of the heating furnace 1 is usually at a high temperature of about 200 ° C. to 300 ° C., and there is also a reflow apparatus in which an inert gas such as nitrogen gas is supplied into the heating furnace 1. Inlet 8 of heating furnace 1
The carry-in section 9 provided in the and the carry-out section 11 provided in the carry-out port 10 are means for making it difficult for the atmosphere in the heating furnace 1 to leak. The heating temperature of the printed wiring board 6 and its profile are selected depending on the type of solder used for soldering, the type of electronic components mounted, and the like.

There are many heating furnaces 1 having a double structure in which a heat insulating material is interposed so as to improve heating efficiency, but the surface temperature of the heating furnace 1 is still more than 100 ° C. It has become.

Then, the heat convection inside the housing 3 generated from the high-temperature heating furnace 1 promotes heat collection to the upper part of the housing 3, and the high temperature part is formed in the upper part of the housing 3. Form. Therefore, a fiber reinforced plastic (FRP) is provided in the upper housing 4 of the housing 3 that covers the heating furnace 1.
The housing 3 is constructed by using an n-forced plastics member and an iron member for the lower housing 5.

As the resin material used for the fiber reinforced plastic, a silicone resin or a polyimide resin can be used in addition to the commonly used phenol resin, unsaturated polyester resin, epoxy resin. Further, as the fiber material, glass fiber, carbon fiber or the like can be used. These are examples, and the present invention is not limited to these.

That is, since the printed wiring board 6 which is the work to be heated has the structure of the heating furnace 1 which is carried into the heating furnace 1 by the carrying conveyor 7, the casing above the carrying conveyor 7 which serves as the heating point. The heat collection by the heat convection is easily promoted in the body part. However, since the casing portion above the transport conveyor 7 (upper casing 4) and at least the casing portion above the heating furnace 1 is made of fiber reinforced plastic, the casing surface temperature is increased. Will be able to lower.

That is, the thermal conductivity of steel is 49 to 37 W.
The thermal conductivity of fiber reinforced plastic is about 0.15 to 0.3 W / (m · K), while that of fiber reinforced plastic is 1/10 of that of steel.
It is 0 or less. As a result, it becomes possible to maintain the surface temperature of the housing portion, which becomes high in the reflow device, at a temperature significantly lower than the conventional temperature.

As a result, it is possible to improve the safety of the reflow apparatus for the operating worker and to form a safe working environment. Further, since the gap between the heating furnace 1 and the housing 3 can be made small, the reflow device can be made smaller than the conventional one, and its exclusive floor area can be made small. The housing 3
Since it becomes possible to reduce the heat radiation from
Although it is extremely small, the heating efficiency of the heating furnace 1 can be improved.

(2) Embodiment Example-2 With reference to FIG. 2, an embodiment example-2 of the reflow apparatus according to the present invention will be described. FIG. 2 is a perspective view showing the whole of Embodiment 2 of the reflow apparatus of the present invention. That is,
The reflow device described with reference to FIG. 1 is a reflow device configured to open and close an upper housing 4 made of fiber reinforced plastic.
Is a reflow device configured as a maintenance hatch unit 13.

The maintenance hatch portion 13 has its tension and the maintenance hatch portion 1 by means of an opening / closing force balancing means for assisting the opening / closing of the gas spring 14, the damper and the like.
This maintenance hatch part 13 is balanced with the weight of 3
It is configured so that the operator can easily perform the opening and closing work. That is, the gas spring 14, the damper and the like expand and contract in the direction of arrow B to assist the opening and closing by the worker, and the maintenance hatch portion 13 can be easily moved in the direction of arrow C using a pivoting means such as a hinge (not shown) as a pivot. It is configured to open and close.

Since the maintenance hatch portion 13 is made of fiber reinforced plastic as described in the first embodiment shown in FIG. 1, the maintenance hatch portion 13 is light in weight while sufficiently satisfying the strength of the housing 3. be able to. Therefore, it becomes possible to reduce the design pressure of the opening / closing force balancing means such as the gas spring 14 and the damper, and thus it becomes possible to use the small opening / closing force balancing means such as the gas spring 14 and the damper. The cost of the device can be reduced, and the weight of the opening / closing force balancing means can be reduced.

Further, since the maintenance hatch portion 13 can be made lighter than the conventional one, the maintenance hatch portion 13 is
The safety associated with opening and closing can be improved. Of course, similar to the operation of the first embodiment of the above (1), the casing 1
The surface temperature of the reflow device can be lowered, and the reflow device can be made smaller than the conventional one.

(3) Embodiment Example-3 With reference to FIG. 3, an embodiment example-3 of the reflow apparatus according to the present invention will be described. FIG. 3 is a view showing a cross section of the reflow apparatus of the present invention. That is, in the reflow apparatus described with reference to FIG. 1, the upper housing 4 made of fiber reinforced plastic, which is the maintenance hatch portion 13 in FIG. 17 is a reflow device configured to be opened / closed in accordance with the opening / closing of 17, and corresponds to a view showing a cross section of the reflow device shown in FIGS. 1 and 2. An example in which the lid 17 is provided with a heating unit is common.

This reflow apparatus is constructed such that a lid 17 at an upper portion of the heating furnace 1 can be opened and closed centering on a hinge 19 by an air actuator 16 having a fixing portion 16a provided on a frame or the like (not shown). This is an example in which the inside of the heating furnace can be easily maintained. A roller 18 provided above the heating furnace 1 pushes up the maintenance hatch portion 13 to open and close the lid 17 of the heating furnace 1 and to perform maintenance hatching. In this example, the opening and closing of the portion 13 can be performed together. Note that FIG.
2 shows a configuration example using the air actuator 16 of FIG.
Alternatively, the gas spring 14 and the damper shown in FIG.

That is, by expanding and contracting the air actuator 16 in the direction of arrow D with the fixed portion 16a as a reference, the lid 17 of the heating furnace 1 opens and closes in the direction of arrow E, and the maintenance hatch portion 13 centers on the hinge 20. It is configured to open and close in the arrow F direction.

Also in this configuration example, in addition to the action of the first embodiment of the above (1) and the action of the second embodiment of the above (2), the upper housing 4 is made of fiber reinforced plastic. Since it is configured, it is possible to sufficiently satisfy the strength of the housing 3 and to make the housing lightweight, and to reduce the design expansion / contraction force of the air actuator 16, etc., and thus to use the small actuator 16. As a result, the device cost can be reduced and the opening / closing means, that is, the actuator 16
The weight of can also be reduced.

In the above embodiments, only the upper housing 4 which is the convex portion of the housing 3 of the reflow device is made of fiber reinforced plastic, but various housing designs of the reflow device are available. In the reflow apparatus configured as shown by the chain double-dashed line in FIG. 1 (b),
The upper housing 4 shown by the two-dot chain line can be made of fiber reinforced plastic.

[0040]

As described above, according to the reflow apparatus of the present invention, the case portion of the reflow apparatus, which is located above the transport conveyor having the highest temperature, is located at least above the heating furnace. By covering the housing portion with the housing made of the fiber reinforced plastic member, the surface temperature of the housing portion can be lowered and a safe working environment can be formed.

Further, even if the gap between the heating furnace and the case is narrowed, the surface temperature of the case does not rise so much, the reflow device is downsized while ensuring a safe working environment, and its own floor is used. It is also possible to reduce the area.

Further, by using the fiber reinforced plastic for the maintenance hatch portion of the housing, it is possible to reduce the weight while sufficiently satisfying the strength of the housing. The actuator for opening and closing the section and the opening and closing force balancing means can be downsized and can be constructed at low cost and light weight. Also,
By reducing the weight of the maintenance hatch, the safety associated with opening and closing work is also improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of a reflow device according to the present invention.

FIG. 2 is a perspective view showing the entire contents of Embodiment 2 of the reflow device of the present invention.

FIG. 3 is a view showing a cross section of Embodiment-3 of the reflow device of the present invention.

[Explanation of symbols]

1 heating furnace 2 heating chambers 3 housing 4 Upper case 5 Lower case 6 printed wiring board 7 Conveyor 8 entrance 9 carry-in section 10 carry-out exit 11 carry-out section 13 Maintenance hatch part 14 gas spring 16 actuators 16a Fixed part 17 Lid 18 Laura 19 hinge 20 hinges

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Claims (2)

[Claims] 1. A reflow apparatus having a housing for covering a heating furnace and carrying a printed wiring board into the heating furnace by a carrying conveyor for soldering, wherein the housing is located above the carrying conveyor. The reflow apparatus, wherein at least the upper casing part of the heating furnace is made of a fiber reinforced plastic member. 2. A reflow apparatus having a casing for covering a heating furnace, wherein a printed wiring board is carried into the heating furnace by a carrying conveyor for soldering, wherein the housing is above the carrying conveyor. And a maintenance hatch portion for opening and closing at least the upper side portion of the heating furnace is formed of a fiber reinforced plastic member, and the maintenance hatch portion is an actuator for driving the opening and closing or an opening and closing force balance for assisting the opening and closing. A reflow apparatus comprising means.