JPH09326553A - Operation control method of reflow soldering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a reflow soldering operation of high quality to be carried out by a method wherein the inside of a treating oven provided to a reflow soldering device can be observed always. SOLUTION: A window 10 is provided to an oven 4 so as to observe the inside of the oven 4 provided to a reflow soldering device, and a see-through window 31 and a window holder 22 which holds the see-through window 31 in a detachable, openable, and airtight manner are provided to the window 10, whereby the operating see-through window 31 is replaced with a new one to observe the inside of the oven 4 when it gets stained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a solder such as a printed wiring board on which electronic parts are mounted, which has been previously supplied to a soldered portion of a workpiece to be soldered in a furnace body such as a chamber. The present invention relates to a method of operating a reflow soldering apparatus that heats and melts a portion to be soldered by a heating means, and particularly relates to a method of facilitating the operation.

[0002]

2. Description of the Related Art A reflow soldering apparatus heats a printed wiring board with a heating medium such as infrared rays or hot air to melt the solder previously supplied to a soldered portion on which an electronic component is mounted, thereby performing soldering. It is a device to perform. In a device for collectively reflow soldering the parts to be soldered, heating means for discharging the heating medium is generally provided in the furnace body such as a chamber to heat the printed wiring board. .

FIG. 6 is a perspective view showing the entire contents of a heating furnace in a conventional reflow soldering apparatus, and FIG. 7 is a line I- of FIG.
It is sectional drawing by the I line.

In these drawings, the heating furnace 3 of the reflow soldering apparatus generally has a structure in which a plurality of heating chambers 5, 6, 7 formed by a furnace body 4 are provided along a transfer path of a transfer conveyor 2. With such a configuration, the printed wiring board 1 can be continuously soldered and the controllability of the heating profile is improved. The example of FIGS. 6 and 7 is an example of a reflow soldering apparatus including a temperature raising part heating chamber 5, a temperature equalizing part heating chamber 6 and a reflow part heating chamber 7. The wall forming the furnace body 4 has a layered structure in which a heat insulating member (not shown) is interposed inside to suppress an increase in thermal efficiency and an increase in the outer wall temperature of the furnace body 4.

As the heating means 8, an infrared heater, a hot air supply device (composed of an atmosphere heating heater and a blower fan), or a combination of an infrared heater and a hot air supply device is used. Although FIG. 7 shows a configuration example in which heating means 8 are provided above and below the conveyer conveyor 2 and both sides of the printed wiring board 1 can be collectively reflow-soldered, the heating means 8 is provided only above the conveyer conveyor 2. There is also an apparatus in which only the upper surface side of the printed wiring board 1 is provided by reflow soldering.

The printed wiring board 1 is sequentially conveyed by the conveyor 2 from the temperature raising section heating chamber 5 through the temperature equalizing section heating chamber 6 to the reflow section heating chamber 7 in the direction of arrow A, and the reflow section heating chamber In step 7, the solder supplied to the part to be soldered is melted and soldering is performed.

In the reflow soldering apparatus, what heating profile the printed wiring board 1 is heated is important. That is, the heating profile serves as an important index in order to prevent the flux from losing its activity before the solder is melted and to prevent soldering defects such as the occurrence of solder balls and tombstones and poor wetting. Therefore, a temperature sensor is attached to each part of the printed wiring board 1 to measure the transition and history of the temperature rise in the heating furnace 3.

[0008]

Since the heating profile is measured by providing temperature sensors at several places, the heating profile is supplied to each soldered portion of a large number of components mounted on the printed wiring board 1. There is no way to know how the solder melts, or how. This is because the furnace body 4 of the reflow soldering device is composed of a metal wall.

It is desirable for uniform soldering that all the solders of the parts to be soldered on the printed wiring board 1 are melted, but in reality, the printed wiring board 1 is sequentially reflow heated by being transported. Since the heating and heating rate is slightly different depending on the entering into the chamber 7, the type and size of the parts, the material and the color tone, etc., the moment of melting of the solder is also slightly different. Then, the soldering quality is deteriorated due to such a thing. This is a matter that cannot be known by measuring the heating profile, but is a very important matter for obtaining good solderability.

Therefore, there is a technique in which a furnace window of a reflow soldering apparatus is provided with a see-through window for observing a printed wiring board. FIG. 8 is a perspective view showing another example of the conventional reflow soldering device extracted from Japanese Utility Model Laid-Open No. 63-25258. That is, transparent material (for example, heat-resistant glass)
This is a technique in which an observation window 12 is provided at 11, and a state of a printed wiring board (not shown in FIG. 8) that is transported by the transport conveyor 13 and soldered in the furnace body 14 can be observed.

However, in this technique, the flux fumes existing in the high temperature atmosphere inside the furnace body 14 adhere to the transparent material 11, and eventually the printed wiring board (not shown) inside the furnace body 14 cannot be observed. Therefore, periodical cleaning work is required, but this cleaning work needs to be performed after the operation of the reflow soldering device is stopped. You cannot observe the inside of 14.

Further, when this work is performed at times other than the time when the reflow soldering apparatus is normally operated, that is, before or after the start time of the factory, the worker who performs the cleaning work is far before the start time. It is necessary to go to work early or to work overtime until the end of the working hours.

FIG. 9 is a time chart for explaining an example of the operating state of the normal reflow soldering device shown in FIG. That is, for example, if the factory start time is 9 o'clock, the reflow soldering apparatus is programmed by a timer to automatically start about 1 hour before the start time, that is, at 8 o'clock. This is because it is necessary to raise the temperature inside the furnace body 14 of the reflow soldering apparatus to a normal operating state in order to start production without delay at the same time as 9:00 of the start of work. Then, the operation of the reflow soldering apparatus is stopped at 17:00 at the end of work.

Therefore, in order to perform the cleaning work of the window portion 12 made of the transparent material 11 as described above without soldering work, that is, without delaying or stopping the production, at least two hours before the start time, for example, 7 o'clock. Around that time, I will come to work early or do the cleaning work, or after the operation of the reflow soldering equipment is stopped at 17:00, the furnace body 14 etc. will cool naturally and the temperature will drop to a temperature at which the cleaning work can be carried out safely. After that, it is necessary to work overtime and perform cleaning work after 18:00, for example.

That is, in addition to imposing a great burden on the worker who carries out the cleaning work, the manager must bear the economic burden of increasing the production cost of paying wages due to early work or overtime work.

Even if the high-temperature furnace body 14 can be temporarily opened to perform the cleaning operation during the operation of the reflow soldering apparatus, it poses a great risk and is not preferable from the viewpoint of occupational health and safety. It is work. Further, in an apparatus for supplying an inert gas such as nitrogen gas into the furnace body 14 to perform reflow soldering in a low oxygen concentration atmosphere, the furnace body 1
By temporarily opening No. 4, the atmosphere enters the furnace body 14, and a large amount of time is required until the atmosphere in the furnace body 14 is restored to a predetermined oxygen concentration, and nitrogen gas is wasted.

An object of the present invention is to constantly observe the inside of the furnace of the reflow soldering apparatus, so that high quality reflow soldering work can be performed without lowering productivity and increasing production cost. Is to be able to do.

[0018]

SUMMARY OF THE INVENTION The present invention provides a plurality of removable plugs for observing the inside of a furnace of a reflow soldering apparatus by observing the inside of the furnace while hermetically sealing the window. Prepare a transparent window body and attach one of them to the window to observe the inside of the furnace, and remove the transparent window body that became difficult to see through by transparent observation due to dirt accumulation. It is characterized in that it can be replaced with a window body in an extremely short time. As a result, the reflow soldering device can always observe the inside of the furnace while operating normally. Further, the see-through window body removed due to being dirty can be separately cleaned.

That is, since the dirty see-through window body and the clean see-through window body can be exchanged in an extremely short time, the atmosphere inside the furnace body flows out from the window portion of the furnace body, or conversely, the atmosphere outside the furnace body enters the furnace body. This is because there is no inflow and there is no effect on the furnace atmosphere temperature or oxygen concentration that regulates the reflow soldering conditions.

In addition, when observing the state of soldering inside the furnace body as necessary, it is not necessary to observe the inside of the furnace body at all times, so a lid body having the same size as the transparent window body is attached. Only when observing the inside of the furnace, it may be used by replacing it with the transparent window body. As a result, the adhesion of the flow to the see-through window body is extremely reduced, and good observation can be performed for a long period of time.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a description will be given of how the operation method of the reflow soldering apparatus according to the present invention can be practically implemented.

An observation window is provided in the heating chamber of the heating furnace of the reflow soldering apparatus so that the process of melting the solder in the soldered portion of the printed wiring board can be observed.

That is, an observation window portion is formed on the wall of the furnace body, and a transparent window body for observing the inside of the furnace body is formed in the window portion, and the transparent window body can be opened / closed / removed and kept airtight. A holding body is provided.

The see-through window body can be opened and closed with a hinge as a fulcrum, and can be inserted into and withdrawn from the slot of the holding body in which the window portion is formed. Then, after inserting the transparent window body into the slot, the holding body is pressed against the furnace body, and the pressing plate portion is pressed by the pressing piece of the fixing tool and fixed.

The transparent window body is made of heat-resistant glass on both sides of the frame body, and is hermetically sealed to the furnace body by a sealing member.

When it is not always necessary to observe the inside of the furnace, a lid without a window is used in place of the transparent window body to prevent the transparent window body from being contaminated.

[0027]

FIG. 1 is a perspective view showing an example of a reflow soldering apparatus for carrying out the present invention. The same reference numerals as those in FIG. 6 indicate the same parts, and the entire heating furnace 3 of the reflow soldering apparatus will be described. FIG. That is, the reflow part heating chamber 7 is provided with the observation window 21 so that the process of melting the solder in the soldered part of the printed wiring board 1 can be observed. The present invention is characterized by the structure of the observation window 21 and its operation method.

FIG. 2 shows the entire view of the observation window 21 and the furnace body 4 of FIG.
Fig. 2 is an enlarged perspective view of a part of the
The detachment mechanism is shown. That is, in the furnace body 4, a window portion 10 is formed as a hole for observation in a wall in which the heat insulating member 9 is interposed, and in the window portion 10, a transparent window body 31 for observing the inside of the furnace body 4,
The transparent window body 31 is provided with a holding body 22 that can be opened / closed / removably attached and is airtightly held.

The see-through window body 31 is opened and closed with the hinge 24 as a fulcrum, and is inserted and removed by inserting it into the slot 25 of the holder 22 having the window portion 23 and pulling it out.
After inserting the transparent window body 31 into the slot 25, the holding body 22
Is pressed against the furnace body 4 and the pressing plate portion 26 is pressed by the pressing piece 42 of the fixture 41 to be fixed. The pressing piece 42 is provided on a knob 43 that rotates, and the fixing operation can be performed by rotating the knob 43. Further, 44 is a pedestal having the same thickness as the pressing plate portion 26, and is fixed to the furnace body 4.

The window portion 23 of the holding body 22, the window portion 32 of the transparent window body 31 and the window portion 10 of the furnace body 4 are provided so as to be aligned with each other, and when the holding body 22 is fixed by the fixture 41, the furnace body 4 is obtained.
A sealing member (silicon rubber) (not shown) provided on the outer wall of the above-mentioned structure abuts on the frame body 33 of the transparent window body 31.
Further, 34 is a heat-resistant glass forming the window portion 32 of the transparent window body 31, and 35 is a handle.

3 (a) to 3 (d) are side sectional views showing examples of the constitution of the transparent window body 31 and the lid body, and FIG. 3 (a) shows an example using only the heat-resistant glass 34. (B) is heat-resistant glass 3
4 and a convex lens are used, FIG. 3 (c) shows an example in which a heater for heating the heat-resistant glass 34 on the inner side of the furnace body 4 is provided, and FIG. 3 (d) shows the furnace body 4. An example of a lid for closing the window 10 is shown. The same reference numerals as those in FIG. 2 indicate the same parts.

That is, in the example of FIG. 3A, the frame 33
The window portions 32 are provided on both surfaces of the above, and heat resistant glass 34 such as quartz glass is attached to both window portions 32 and fixed by bushing members 36. As a result, the amount of heat that escapes from the transparent window body 31 can be reduced while ensuring the transparency. The handle 35 is for gripping when the transparent window body 31 is inserted into or removed from the slot 25 of FIG.

Next, in the example of FIG. 3 (b), a convex lens 37 for enlargement is provided on the observer side, and the basic structure is the same as that of FIG. 3 (a). The focal length of the convex lens 37 is determined by the position of the printed wiring board (not shown) to be observed. That is, the focal length is suitable for magnifying observation of the printed wiring board.

Further, the example of FIG. 3C is a structural example provided with a heater wire 38 for heating the heat resistant glass 34 facing the inside of the furnace body 4, and the heater wire 38 includes two heat resistant glass 34.
The structure is interposed between the heat-resistant glass and the heat-resistant glass so that the heat-resistant glass can be heated uniformly within a range that does not hinder observation. Specifically, it is desirable that the wires are arranged in a meandering shape.
The heater wire 38 is connected to the power source by the connector 39, and is connected in accordance with the attachment / detachment of the transparent window body 31.

The heat-resistant glass 3 facing the inside of the furnace body 4 in this way
By heating No. 4, flux fume will condense.
Adhesion is reduced and cleaning is unnecessary for a long period of time. This heating temperature is, for example, the temperature 240 in the furnace body 4.
A sufficient effect can be obtained at about 300 to 400 ° C with respect to ° C.

Further, the example of FIG. 3 (d) is shown in FIG.
A box-shaped lid 40 without the window 32 shown in (c) has a heat insulating member 9 enclosed therein. The lid 40 is used when it is unnecessary to observe the inside of the furnace body 4, and prevents the transparent window body 31 from being soiled.

FIG. 4 shows the furnace body 4 with the transparent window body 3 of FIG.
1 is a side sectional view showing a mode in which 1 is used, and shows a state in which the transparent window body 31 and the lid body 40 are actually inserted into the slots 25 of the holding body 22 and fixed to the furnace body 4 by the fixtures 41. .

The size of the window portion 10 of the furnace body 4 and the transparent window body 31
The window portions 32 of the holder 22 have the same size.
Is larger than these windows 23 and 32. A sealing member 27 made of a material such as silicon rubber is provided on the edge of the window portion 10 of the furnace body 4. The transparent window body 31 is inserted into the slot 25 and the slot 25 is pressed against the furnace body 4 to be fixed. When fixed with the tool 41, the sealing member 27 comes into contact with the frame 33 of the transparent window body 31 to hermetically seal the furnace body 4. The procedure for extracting the transparent window body 31 is the reverse of this.

As described above, the transparent window body 31 and the lid body 40 are detachable by inserting them into the slots 25 of the holding body 22 and pulling them out, and they can be attached and detached in an extremely short time. And the airtightness of the heating furnace 3 is also maintained. Further, the time required for attaching and detaching the transparent window body 31 and the lid body 40 is extremely short, and the atmosphere in the furnace body 4 is changed during the attachment and detachment.
There is almost no leakage to the outside or the atmosphere outside the furnace body 4 entering the furnace body 4.

Furthermore, the flux fume which is likely to adhere to the heat-resistant glass 34 of the window 32 can be easily cleaned by opening the holder 22. Further, it can be removed from the slot 25 of the holder 22 for cleaning. Also, FIG.
If the transparent window member 31 heated by the heater shown in FIG. 3C is used, the adhesion of flux fumes is extremely reduced. That is, with these configurations, it is possible to constantly observe the process of melting the solder in the soldered portion of the printed wiring board 1, and the influence on the operating state of the reflow soldering apparatus (the temperature inside the furnace and the atmosphere inside the furnace). Effect on oxygen concentration, etc.) is eliminated.

As a result, it becomes possible to constantly observe the moment of the process of melting the solder supplied to the soldered portion without affecting the operating state of the reflow soldering apparatus, and to improve the heating profile. It is possible to observe parameters that cannot be obtained by the measurement of. As a result, the soldering quality can be improved. Moreover, by such a driving operation method, the cleaning work of the transparent window body 31 which is conventionally required to be performed outside the working hours of the worker, that is, outside the normal operating time of the reflow soldering apparatus, is eliminated, and It becomes possible to carry out the cleaning work. Therefore, the burden on the operator is significantly reduced and the production cost is not increased.

Further, by using the transparent window body 31 having the convex lens 37 shown in FIG. 3B, the soldered portion of the printed wiring board 1 can be magnified and observed, and the observation is extremely easy. You will be able to.

For example, it becomes possible to visually grasp the solder melting process when the tombstone phenomenon, which is likely to occur due to the difference in solder melting timing, occurs.
As a countermeasure against this, it becomes possible to prevent the occurrence of the tombstone phenomenon by adjusting the irradiation amount of infrared rays and the wind speed of hot air so that the solder melting timings are aligned.
Further, it is also possible to find a portion having a slow melting timing, which is one of the causes of the non-wetting failure, and adjust the irradiation amount of infrared rays or the wind speed of hot air so as to improve the melting delay of the portion. Furthermore, it becomes possible to discover the factors that are responsible for the pattern design of the printed wiring board.

That is, it is possible to always directly visually observe an event that was previously inferred based on the data obtained from the heating profile and the defect occurrence information (solder quality information) obtained from the soldering result. As a result, it becomes possible to improve the soldering quality, facilitate process control and quality control of the soldering process, and manufacture a high-quality printed wiring board.

When it is not necessary to observe the printed wiring board 1, a cover 40 as shown in FIG.
By inserting it into the slot 25 of the transparent window body 3
There is no need to consider the dirt of 1 at all, opening and closing of the above-mentioned
Coupled with the fact that it can be freely attached and detached in a very short time, the operability is extremely good.

Next, another embodiment of the opening / closing / attaching / detaching mechanism of the observation window 21 will be described. FIG. 5 is a perspective view showing another embodiment of the present invention, which is an example configured so that the time for replacing the transparent window member 31 can be further shortened. That is, the configuration is such that the slot 52 is formed in the lateral direction of the holding body 51, and the saucer portion 53 is provided so that the transparent window body 31 can be slid and inserted. Further, 54 is a holding plate portion, and 55 is the holding body 5.
It is the window part of 1. In addition, the same reference numerals as those in FIG. 2 indicate the same parts.

The replacement work of the transparent window body 31 is performed in the following procedure, for example. First, a new clean transparent window body 3 to be replaced.
1 is placed on the right side of the saucer portion 53 in the figure, and then the knob 43 of the fixture 41 is turned in the direction of the arrow to open the holding body 51 in the direction of the arrow. Subsequently, at least the front end portion of the transparent window body 31 to be inserted is placed on the saucer portion 53, and then the transparent window body 3 is inserted first while sliding in the direction of the arrow.
Push 1 in the direction of the arrow. Then, after closing the holding body 51 in the arrow direction, the knob 43 of the fixture 41 is turned in the arrow direction to fix the pressing plate portion 54 of the holding body 51, and the operation is completed. That is, the holding body 51 is open for a very short time.

When the new clean transparent window body 31 is inserted as described above, the transparent window body 31 extruded on the left side of the drawing may be taken out from the tray 53 and the necessary cleaning work may be performed.

The replacement work of the transparent window body 31 is shown in FIG. 3 (d).
The same can be done with the lid 40. That is, normally, the transparent window body 31 is used only when it is necessary to use the lid body 40.
It can be exchanged, attached and detached, and the state of the printed wiring board 1 can be observed.

[0050]

As described above, according to the operation method of the reflow soldering apparatus of the present invention, the operation state of the reflow soldering apparatus is not restricted and the operation state of the reflow soldering apparatus is affected. Without giving
It is possible to constantly observe the reflow soldering process and further perform the cleaning operation of the see-through window body within the normal operation time. Further, the burden on the worker is not given and the cost for the driving operation is not increased.

If a lid having the same size as the transparent window is used, the transparent window can be replaced with the transparent window only when the reflow soldering process needs to be observed. Can be kept to a minimum.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example in which an observation window is attached to a reflow soldering device for carrying out the present invention.

FIG. 2 is a perspective view showing an entire view of an observation window of FIG. 1 and a part of a furnace body in an enlarged manner.

3A and 3B are side sectional views showing a configuration example of a see-through window body and a lid body, FIG. 3A is an example using only heat-resistant glass, FIG. 3B is an example using heat-resistant glass and a convex lens, and FIG. 3 (c) shows an example provided with a heater for heating the heat-resistant glass on the side in contact with the inside of the furnace body, and FIG. 3 (d) shows an example of a lid body for closing the window portion of the furnace body. .

FIG. 4 is a side sectional view showing a mode in which the transparent window body of FIG. 3 (a) is used for the furnace body.

FIG. 5 is a perspective view showing another embodiment of the observation window of the present invention.

FIG. 6 is a perspective view showing the entire contents of a heating furnace of a conventional reflow soldering device.

FIG. 7 is a sectional view taken along line II of FIG. 6;

FIG. 8 is a perspective view showing another example of a conventional reflow soldering device.

FIG. 9 is a time chart explaining an operating state of the normal reflow soldering device shown in FIG. 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Conveyor 3 Heating furnace 4 Furnace body 5 Heating part heating chamber 6 Temperature equalizing part heating chamber 7 Reflow part heating chamber 10 Window part 21 Observation window 22 Holding body 23 Window part 24 Hinge 25 Slot 26 Holding plate part 31 Transparent Window Body 32 Window Section 33 Frame Body 34 Heat-Resistant Glass 37 Convex Lens 38 Heater Wire 40 Lid Body 41 Fixing Tool 51 Holding Body 52 Slot 53 Sauce Plate Section 54 Holding Plate Section 55 Window Section

Claims (2)

[Claims] 1. A method for operating a reflow soldering apparatus, comprising: melting a solder, which is previously supplied to a soldered portion of a soldered work, in a furnace by a heating means; and soldering the soldered portion. A window portion for observing the soldered work in the furnace body is provided in the furnace body, and a plurality of detachable transparent window bodies for observing the furnace body while hermetically sealing the window portion are prepared in advance. , One of the plurality of transparent window bodies is attached to the window portion to observe the inside of the furnace, and when the transparent window body is soiled, the transparent window body is removed to provide another transparent body. A method of operating a reflow soldering device, characterized in that a window is attached. 2. A method of operating a reflow soldering device, wherein the solder supplied in advance to a soldered portion of a work to be soldered is melted in a furnace by a heating means, and the soldered portion is soldered. A window portion for observing the soldered work in the furnace body is provided in the furnace body, and the detachable transparent window body and the transparent window body for observing the furnace body while hermetically sealing the window portion are the same. Prepare a lid of a size, attach the lid to the window when observation inside the furnace is unnecessary, and remove the lid only when observation inside the furnace is necessary. The operation method in a reflow soldering device, characterized in that the transparent window body is attached.