JPH10126050A - Heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device which can uniformly blow hot blasts upon a work to be heated by arranging a plurality of bar-like infrared heater units in a line and forming slit-like nozzle sections and horn sections which are successively provided from the nozzle sections between each heater unit. SOLUTION: Heat-conductive cement 15 is applied to heater units 11 and, at the same time, a hot blast flowing-in route, namely, a slit-like nozzle section 12 and a hot blast flowing-out route, namely, a slit-like horn section 14 are housed in each casing 17. The lower surfaces, namely, infrared radiating surfaces 18 of the units 11 which are not housed in the casings 17 are constituted so that the surfaces can efficiently radiate far infrared rays. The far infrared rays radiated from the units 11 uniformly irradiate a work to be heated, such as the printed wiring board, etc. Since the hot blasts blown from the nozzle sections 12 are spread by means of the horn sections 13, the hot blasts are uniformly blown upon the work to be heated over a wide extent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating apparatus for irradiating a workpiece to be heated, for example, a printed wiring board with infrared rays and blowing hot air to heat the workpiece.

[0002]

2. Description of the Related Art Workpieces to be heated have different infrared absorptivity and thermal conductivity from hot air to the work to be heated depending on their material and color tone. It is known that infrared irradiation and hot air blowing may be used in combination.

For example, when reflow soldering is performed on a portion to be soldered of a printed wiring board on which various electronic components are mounted as a work to be heated at once, the material and color tone of each electronic component are different. Infrared heating and hot air heating are used in combination to uniformly heat them and improve solderability.

FIG. 7 shows a conventional "reflow soldering apparatus".
3 is a cross-sectional view showing a main part of the present invention, which is an excerpt from Japanese Utility Model Publication No. 3-15254.

That is, in this figure, 1 indicates a printed wiring board, and 2 indicates a part of a body (furnace body). Reference numeral 3 denotes a housing, 4 denotes a conveyor, and 5 denotes a rectifying frame having a U-shaped cross section. These rectifying frames 5 are arranged to form slit-shaped nozzles 6 between the rectifying frames 5, respectively. This is a configuration in which a far-infrared heater 7 is provided in the rectification frame 5. The atmosphere blown from the fan 9 driven by the motor 8 is heated by the fin heater 10 and then blown out from the slit-shaped nozzle 6 and blown onto the printed wiring board 1 conveyed by the conveyor 4. Further, the printed wiring board 1 is also irradiated with far infrared rays radiated from the respective far infrared heaters 7 provided in each rectification frame 5.

As a result, the irradiation of the infrared rays and the blowing of the hot air onto the printed wiring board 1 are performed simultaneously.

[0007]

However, in the above-mentioned prior art, the hot air blown out from the slit-shaped nozzle 6 concentrates only on a partial area of the printed wiring board 1, that is, on a part located below the nozzle 6. It is blown at a high flow rate, and only the very slow hot air is blown to other parts. Therefore, when the heating profile of the printed wiring board 1 is measured, there is a problem that the heating temperature has a ripple, that is, a small temperature fluctuation (pulsation), and the temperature of the printed wiring board 1 rises unstablely.

That is, while infrared rays radiated from the infrared heater 7 are radiated in a wide range, hot air blows only downward of the slit-shaped nozzle 6 and the lower part of the slit-shaped nozzle 6 is This is because the temperature rise due to the hot air appears only when the air passes.

[0009] It is an object of the present invention to provide a heating apparatus capable of uniformly blowing hot air to a work to be heated and further improving the efficiency of infrared heating even when both infrared heating and hot air heating are used. It is to realize.

[0010]

That is, a plurality of rod-shaped infrared heater units are arranged and arranged, and a slit-shaped nozzle portion is provided between each rod-shaped infrared heater unit and connected to the nozzle portion. This is a heating device configured to form a horn portion. Thereby, the hot air blown out from the nozzle portion is diffused in the horn portion, and the hot air blows out over a wide range not defined by the width of the slit-shaped nozzle portion. In addition, infrared rays are radiated from the respective rod-shaped infrared heater units over a wide range, so that it is possible to irradiate the infrared rays while uniformly blowing hot air onto the work to be heated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be implemented in the following modes.

(1) A device for heating a work to be heated by blowing hot air together with the irradiation of infrared rays, wherein rod-shaped infrared heater units are arranged and arranged, and an atmosphere is provided between the rod-shaped infrared heater units. To form a slit-shaped nozzle part in which the flow path of the atmosphere narrows in the flow direction of the air, and a slit-shaped horn part connected to the nozzle part of the slit and in which the flow path of the atmosphere spreads in the flow direction of the atmosphere. Configure.

Thus, the hot air blown out from the nozzle portion is radiated in the horn portion, and the hot air can be blown out over a wide range which is not limited by the slit width of the nozzle. In addition, infrared rays are radiated from the rod-shaped infrared heater unit over a wide range.

(2) In the above (1), the rod-shaped infrared heater unit is configured such that a heat-conductive cement is applied to the surface of the heater, and a casing is applied to the slit-shaped nozzle portion and the slit-shaped horn portion. I do.

The heat-conductive cement is made of a hardening inorganic material, and its component is known to be made of sodium silicate and graphite. It is extremely easy to freely form the heater shape due to its self-curing property, the thermal conductivity is large, and the responsiveness of a temperature change to a temperature change of the heater is extremely excellent. In addition, its component graphites are very good infrared emitting materials which emit abundant infrared over a wide wavelength range when heated, and emit a very large amount of far infrared from a thick layer of thermally conductive cement.

By providing a casing on the slit-shaped nozzle portion and the slit-shaped horn portion, far-infrared rays radiated from the heat-conducting cement emit an atmosphere blown from the nozzle portion and the horn portion, that is, a blowing direction of hot air. That is, the radiation is efficiently radiated toward the workpiece to be heated.

Thus, hot air is blown over a wide range not defined by the slit width of the slit-shaped nozzle portion, and a large amount of far-infrared rays over a wide wavelength range are radiated from the rod-shaped infrared heater unit, and the work to be heated is irradiated with infrared rays. The combined use of the hot air enables uniform and efficient heating.

(3) In the above (1) and (2),
The surface of the rod-shaped infrared heater unit with respect to the workpiece to be heated is configured such that the cross-sectional shape is formed in an arc shape.

Thus, the infrared rays radiated from the rod-shaped infrared heater unit are radially radiated to a wider area, and the infrared rays can be uniformly irradiated over a wide area. That is, heating by infrared rays can be performed more uniformly.

[0020]

Next, specific examples of the heating device according to the present invention will be described with reference to examples.

<Heater Array Constituting Heating Device> FIG. 1
1 is a perspective view showing one embodiment of the present invention, and shows a configuration of a rod-shaped infrared heater unit (hereinafter, simply referred to as a heater unit) 11 constituting a heating device and an arrangement structure thereof. That is, the heater units 11 are arranged in a line, and a slit-shaped nozzle portion 12 and a slit-shaped horn portion 13 are formed between these heater units 11.

The heater unit 11 includes a sheath heater 14
A heat conductive cement 15 is applied to the surface of the heater unit 11 and hardened, and the shape thereof is formed into a pentagonal cross section by an apex angle 16 on an upper side and a side side of the heater unit 11 as shown in FIG. It is configured to be.

The inventor of the present invention has filed a Japanese Patent Application No. Hei 8-1472, which has been filed.
As described in No. 1, a technique has been developed in which a heater is made of heat-conductive cement to obtain excellent heating characteristics and easy manufacturing.

That is, the heat-conductive cement 15 is made of a hardening inorganic material, and its component is known to be 32% of sodium silicate and 68% of graphites. The thermal conductivity is 7-1.
It is about 2 kcal / mh ° C, and the thermal conductivity of stainless steel used as the sheath of the sheathed heater is 14 kcal.
/ Mh ° C or more, which is about the same as that of the metal material.

The heat-conductive cement 15 is very easy to freely form a heater shape due to its self-hardening property, has a high thermal conductivity, and has extremely excellent response to a temperature change with respect to a temperature change of the heater. (By the way, the thermal conductivity of ceramics, which is a far-infrared radiation material, is a value of about 1 kcal / mh ° C., depending on the material, and is small). The component graphite is a very good far-infrared ray radiating material which is not inferior to that of far-infrared ray radiating ceramic material.

That is, far infrared rays can be radiated extremely favorably by the heater unit 11. Incidentally, in the present embodiment, the heat conductive cement 1 described above is used.
In addition to 5, alumina was used by mixing at a ratio of 1: 1. As a result, far-infrared radiation characteristics (characteristics in a radiation wavelength spectrum) of the alumina itself are added, and further consideration is added so that the overall radiation characteristics match the infrared absorptance of the work to be heated.

As shown in FIG. 1, a heat-conductive cement 15 is applied to the heater unit 11, and
The casing 17 is provided on the hot air inflow channel, that is, the slit-shaped nozzle section 12 and the outflow path, that is, the slit-shaped horn section 13, and the lower surface in the drawing, that is, the lower side where the casing 17 is not provided. The surface, that is, the infrared radiation surface 18 is configured to efficiently emit far infrared rays. The far infrared rays radiated from the aligned heater units 11 are shown in FIG.
In this example, a work to be heated such as a printed wiring board (not shown) is uniformly irradiated.

Further, the casing 17 improves the mechanical strength of the heater unit 11 and makes the heat conductive cement 1
5 also contributes to improving the retention.

By forming the infrared radiating surface 18 on the arc-shaped radiating surface 18A as shown by a two-dot chain line, the radiating range of the infrared rays is further increased, and the infrared rays are radiated more uniformly over a wide range, so that a large area is obtained. The work to be heated, such as a printed wiring board, can be more uniformly heated.

The flow of the atmosphere, that is, the hot air is radiated by the horn portion 13 when blowing out from the nozzle portion 12,
Hot air is blown over a wide range that is not defined by the slit width of the nozzle portion 12, and is uniformly blown on a work to be heated (not shown).

FIG. 2 is a perspective view showing the entire heater array in which the heater unit 11 shown in FIG. 1 is formed in a panel shape, in which the heater units 11 are arranged in an array.

The heater array 21 includes an array frame 22
Insertion hole 23 for inserting and holding sheath heater 14
Is provided. The casing 17 constituting each heater unit 11 is fixed to the array frame 22 from the beginning by welding or the like, and a slit-shaped nozzle portion 12 and a slit-shaped horn portion 13 are formed between the casings 17 of the heater unit 11. ing. After the sheath heater 14 is inserted into the heater insertion hole 23, the heat-conductive cement 15 is filled in the casing 17 and then self-hardened.

On the upper side of the array frame 22 in the drawing, that is, on the side where the hot air atmosphere flows, a number of holes 2 are provided.
5 is provided. That is, the flow of the hot air atmosphere is made uniform over the entire heater array 21 by the rectifying plate 24.

With this configuration, abundant far-infrared rays are uniformly applied to a work to be heated (not shown) arranged below the heater array 21 configured in a panel as described above, as shown in the drawing. Hot air is evenly blown at the same time as irradiation, so that heating using far infrared rays and hot air simultaneously can be performed.

<Other Shapes of Infrared Heater Unit>
FIG. 3 is a perspective view showing another shape of the heater unit 11 of FIG.

In FIGS. 1 and 2, the heater unit 11 has a pentagonal pole shape, but may have a shape as shown in FIG.

That is, the slit-shaped nozzle portion 12 and the slit-shaped horn portion 13 are formed between each rod-shaped infrared heater unit (hereinafter simply referred to as a heater unit) 31 and the apex angle 16. ing. The apex angle 16 on the upper side in the figure, that is, on the side where the hot air flows, is for guiding the hot air to each slit-shaped nozzle portion 12, and is configured to reduce the flow resistance of the atmosphere.

In this example, the heater unit 31 has only one apex angle 16, but the horn portion 13 can be constituted by a curved surface to improve the hot air radiating action.

By forming the infrared radiation surface 18 on the arc-shaped radiation surface 18A in the same manner as in FIG. 1, the radiation range of the infrared radiation can be further widened. Will be able to do it.

FIGS. 4A and 4B are front views showing still another shape of the heater unit 11 of FIG. FIG.
4A shows a case where the shape of the heater unit viewed from the front is circular, and FIG.

FIG. 4A shows a case where the rod-shaped infrared heater unit 32 does not have the apex angle 16 shown in FIG. 3 and is formed in a circular shape when viewed from the front, and FIG. The infrared heater unit 33 does not have the apex angle 16 shown in FIG. 3 and is formed in an oval shape when viewed from the front.
7 without being applied. Further, the infrared radiation surface 18 may be formed on an arc-shaped radiation surface 18A as shown by a two-dot chain line.

The other operations are the same as those in FIG.

<Configuration as Reflow Soldering Apparatus>
FIG. 5 is a side sectional view showing a reflow soldering apparatus as an example of a heating apparatus using the heater array 21 of FIG. The reflow soldering device is a heating device used when soldering the printed wiring board 1 and the like on which electronic components are mounted. Solder is supplied in advance to a portion of the printed wiring board 1 to be soldered. 1 is a device for heating an electronic component 1 by infrared rays, hot air or the like to melt the solder and solder the electronic component to the printed wiring board 1.

In the example of the reflow soldering apparatus shown in FIG.
A furnace body 41 is provided along a conveyor 47 that holds the printed wiring board 1 and conveys the printed circuit board 1 in the direction of arrow A.
Inside is a heating device 46 in which a preheating section 44 having one heating section 42 and one temperature equalizing section 43 and a reflow section 45 are connected. Although not shown, the transport conveyor 47 is configured to place and hold and transport the side end of the printed wiring board 1 on the pins of two parallel transport chains, and is generally used. Things.

In the heating section heating chamber 48 of the heating section 42 and the equalizing section heating chamber 49 of the temperature equalizing section 43, two panel heaters 50 are provided above and below the transport conveyor 47, respectively. The upper surface and the lower surface of the printed wiring board 1 conveyed by the conveyor 47 can be heated independently. The heating by the panel heater 50 is mainly performed by infrared rays.

Subsequently, the reflow section heating chamber 51 of the reflow section 45 has a heating chamber structure of a hot air circulation system, and a blower 52.
Is heated to a predetermined temperature by a heater 54 in a hot air heating chamber 53, is blown out from an outlet 55 into the heater array 21, and is blown through the heater unit 11 to the printed wiring board 1. Then, the hot air blown to the printed wiring board 1 is sucked into the blower 52 from the suction port 56 through the recirculation path 57 and supplied to the hot air heating chamber 53 again to circulate. In addition,
The structure of the reflow section heating chamber 51 is the same as that of the conveyor 47.
The upper side and the lower side are the same.

The heater array 21 illustrated in FIG.
Is provided at an outlet 55 of the reflow section heating chamber 51, and hot air is radially blown from the slit-shaped nozzle portion 12 through the slit-shaped horn portion 13 to be uniformly blown to the printed wiring board 1. Also, the heater unit 1
The far-infrared rays emitted from the printed wiring board 1 are also uniformly applied to the printed wiring board 1.

As a result, the printed wiring board 1 being conveyed can be simultaneously and simultaneously heated by infrared rays and hot air, and the printed wiring board 1 can be stably and uniformly heated to a desired level without pulsation of the heating temperature. It becomes possible to heat with a profile.

That is, the printed wiring board 1 carried in from the carry-in entrance 58 and uniformly heated by the panel heater 50 in the preheating section 44 is heated in the reflow section 45 by uniformly applying infrared rays and hot air to heat the solder. It becomes possible to melt uniformly. Thereafter, the printed wiring board 1 is carried out from the carry-out port 59.

Although not shown, each panel heater 50 of the preheating unit 44 has a temperature sensor on its surface, and the power applied to the panel heater 50 is adjusted and controlled based on the temperature detection result to control the panel heater. A temperature control device (not shown) for adjusting the surface temperature of 50 to a desired temperature is provided.

The heater array 21 of the reflow unit 45
A temperature sensor 61 is also provided on the surface of the heater unit 11, and is similarly configured so that the surface temperature of the heater unit 11 can be adjusted and controlled to a desired temperature by a temperature control device (not shown). . Hot air outlet 55
Is provided with a temperature sensor 62 for detecting hot air temperature,
A temperature controller (not shown) for adjusting and controlling the power applied to the heater 54 of the hot air heating chamber 53 to adjust the hot air temperature to a desired temperature is provided.

FIG. 6 is also a side sectional view showing a reflow soldering device as a heating device, and the same reference numerals as those in FIG. 5 denote the same parts.

The reflow soldering apparatus includes a heating section heating chamber 48 of the heating section 42 of the pre-heating section 44 and a temperature equalizing section 4.
Each of the temperature equalizing section heating chamber 49 and the reflow section heating chamber 51 of the reflow section 45 constitutes a heating chamber having a similar structure. As shown in FIG. There is no heater for direct control.

That is, the atmosphere supplied from the fan 72 driven by the motor 71 is blown out from the heater array 21 illustrated in FIG. 2, and the blown-out atmosphere is blown onto the printed wiring board 1 conveyed by the conveyor 47. The structure is such that the atmosphere is circulated to the fan through the atmosphere return path 73 between the furnace body 41 and the heater array 21. Since this atmosphere is heated by the heater array 21, it is hot air. In this example,
A hood portion 74 for allowing the fan 72 to face the heater array 21 is provided.

On the other hand, far infrared rays are radiated from the heater unit 11 of the heater array 21, and are uniformly irradiated on the printed wiring board 1 conveyed by the conveyor 42.

That is, the printed wiring board 1 is heated by the infrared rays emitted by the heater array 21 and is sprayed and heated on the printed wiring board 1 while circulating the atmosphere in the heating chamber.

The reflow soldering apparatus also has the same configuration on the upper and lower sides of the conveyer 47 as in the apparatus shown in FIG. Can be independently heated.

Of course, if only one surface of the printed wiring board 1 needs to be heated, the heater array 21 may be provided either above or below the conveyor 47.

As described above, in the heating device of the present invention, the hot air and the infrared rays are combined and made to act on the printed wiring board 1 uniformly.
Stable heating without fluctuations such as pulsation in the heating profile can be performed, and uniform and stable heating can be performed regardless of the material and color tone of the printed wiring board 1.

[0060]

As described above, the present invention has the following effects corresponding to each claim.

According to the first aspect of the present invention, hot air is blown out over a wide range without being limited to the shape of a slit-shaped nozzle. As a result, the workpiece can be heated stably and uniformly, and the workpiece to be heated can be accurately heated. For example, hundreds of soldered portions can be heated with a stable profile without pulsation (ripple), and uniform soldering can be performed. As a result, high-quality and stable products can be manufactured.

According to the second aspect of the invention, in addition to the effect of the first aspect, excellent infrared radiation characteristics, that is, abundant infrared energy is radiated over a wide wavelength range, and a desired heater shape can be easily formed. In addition to the above, it is possible to obtain more excellent and efficient heating properties.

According to the third aspect of the present invention, in addition to the effects of the first and second aspects, the infrared rays radiated from the rod-shaped infrared heater unit are radiated radially over a wider range. The work to be heated can be more uniformly heated. For example, as in the case of performing reflow soldering of a printed wiring board, even hundreds of soldered portions can be uniformly heated over a large area to perform uniform soldering.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an entire heater array in which the rod-shaped infrared heater unit of FIG. 1 is formed in a panel shape.

FIG. 3 is a perspective view showing another shape of the rod-shaped infrared heater unit of FIG. 1;

4A and 4B are front views showing still another shape of the rod-shaped infrared heater unit. FIG. 4A is a front view of the rod-shaped infrared heater unit when viewed from the front, and FIG. The case of a circle is shown.

FIG. 5 is a side sectional view showing a reflow soldering device as an example of a heating device using the heater array of FIG. 2;

FIG. 6 is a side sectional view showing a reflow soldering device as a heating device.

FIG. 7 is a sectional view showing a main part of a conventional reflow soldering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 11 Rod-shaped infrared heater unit 12 Nozzle part 13 Horn part 14 Sheath heater 15 Heat conductive cement 16 Apex angle 17 Casing 18 Infrared radiation surface 18A Arc radiation surface 21 Heater array 22 Array frame 24 Straightening plate 25 Hole 31 Rod shape Infrared heater unit 32 Rod-shaped infrared heater unit 33 Rod-shaped infrared heater unit 41 Furnace body 42 Heating unit 43 Temperature equalizing unit 44 Preheating unit 45 Reflow unit 46 Heating device 47 Conveyor 51 Reflow unit heating chamber 52 Blower 53 Hot air heating Chamber 54 Heater 55 Air outlet 56 Suction port 57 Return path

Claims (3)

[Claims] An apparatus for heating a work to be heated by blowing hot air in combination with irradiation of infrared rays, wherein a plurality of rod-shaped infrared heater units are arranged and arranged, and a plurality of rod-shaped infrared heater units are arranged between the infrared heater units. A slit-shaped nozzle portion in which the flow path of the atmosphere narrows in the flow direction of the atmosphere, and a slit-shaped horn portion connected to the slit-shaped nozzle portion and in which the flow path of the atmosphere spreads in the flow direction of the atmosphere. A heating device formed. 2. A rod-shaped infrared heater unit is characterized in that a heat-conductive cement is applied to the surface of the heater and formed, and a casing is provided on a slit-shaped nozzle portion and a slit-shaped horn portion. The heating device according to claim 1, wherein 3. The heating device according to claim 1, wherein a surface of the rod-shaped infrared heater unit facing the workpiece to be heated has a cross section formed in an arc shape.