U.S. patent application number 09/881783 was filed with the patent office on 2002-02-21 for reflow soldering apparatus.
This patent application is currently assigned to Yokota Technica Limited Company. Invention is credited to Yokota, Yatsuharu.
Application Number | 20020020695 09/881783 |
Document ID | / |
Family ID | 26597921 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020020695 |
Kind Code |
A1 |
Yokota, Yatsuharu |
February 21, 2002 |
Reflow soldering apparatus
Abstract
A reflow soldering apparatus uses circulated heated gas to
solder electronic components to a printed circuit board while
transporting the printed circuit board mounted with electronic
components on a conveyor chain. A plurality of gas passages for
inflow of heated gas which have openings facing the circuit board,
are provided at intervals in the transport direction of the
conveyor chain. A first passage is provided for the flow of heated
gas into the fan from an opening different from the opening for
inflow and formed in the intermediate portion of the gas passage,
and a second passage is provided for the flow of heated gas into
the fan from openings formed on both ends of the gas passage.
Inventors: |
Yokota, Yatsuharu; (Tokyo,
JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
Yokota Technica Limited
Company
Hachioji-shi
JP
|
Family ID: |
26597921 |
Appl. No.: |
09/881783 |
Filed: |
June 18, 2001 |
Current U.S.
Class: |
219/388 ;
219/400 |
Current CPC
Class: |
B23K 2101/40 20180801;
B23K 1/012 20130101; B23K 1/008 20130101 |
Class at
Publication: |
219/388 ;
219/400 |
International
Class: |
B23K 001/008; B23K
001/012; F27B 009/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 14, 2000 |
JP |
2000-245501 |
Sep 14, 2000 |
JP |
2000-279533 |
Claims
1. A reflow soldering apparatus using circulated heated gas to
solder electronic components to a circuit board while transporting
said circuit board mounted with electronic components on a conveyor
through a heating chamber, said reflow soldering apparatus
comprising a plurality of gas passages formed at intervals along
the transport direction of said conveyor, said gas passage having
an opening for inflow of heated gas on the side facing said circuit
board, and a first passage for the flow of heated gas into a
blowing means from an opening different from said opening for
inflow and formed in an intermediate portion of said gas
passage.
2. A reflow soldering apparatus according to claim 1, wherein said
reflow soldering apparatus has a second passage for the flow of
heated gas into said blowing means from an opening formed in an end
portion of said gas passage.
3. A reflow soldering apparatus according to claim 1, wherein said
gas passage is a long, narrow passage intersecting the conveyor
transport direction.
4. A reflow soldering apparatus according to claim 1, wherein a gas
passage for blowing heated gas onto said circuit board is formed
between said gas passages for inflow of heated gas.
5. A reflow soldering apparatus according to claim 1, wherein a gas
passage for blowing heated gas onto said circuit board is formed
between each of said gas passages for inflow of heated gas.
6. A reflow soldering apparatus according to claim 4, wherein said
gas passage for blowing heated gas is a long, narrow passage
intersecting the conveyor transport direction.
7. A reflow soldering apparatus according to claim 2, wherein said
blowing means has intake openings on both opposite sides, and the
heated gas flowing through said first passage is drawn into one of
said intake openings, and the heated gas flowing through said
second passage is drawn into the other intake opening.
8. A reflow soldering apparatus according to claim 2, wherein said
blowing means has intake openings on said circuit board side and on
the opposite side, and the heated gas flowing through said first
passage from said opening formed in the intermediate portion of
said gas passage is drawn into said intake opening provided on the
circuit board side of said blowing means, and the heated gas
passing through said second passage from said opening formed in the
end portion of said gas passage is drawn into said intake opening
provided on the opposite side from the circuit board.
9. A reflow soldering apparatus according to claim 1, wherein said
blowing means has an intake opening on one side.
10. A reflow soldering apparatus according to claim 1, wherein said
blowing means has an intake opening on said circuit board side, and
the heated gas flowing through said first passage from said opening
formed in the intermediate portion of said gas passage is drawn
into said intake opening of said blowing means.
11. A reflow soldering apparatus according to claim 2, wherein said
blowing means has an intake opening on said circuit board side, and
the heated gas flowing through said first passage from said opening
formed in the intermediate portion of said gas passage is drawn
into said intake opening of said blowing means, and the heated gas
passing through said second passage from said opening formed in the
end portion of said gas passage is drawn into said intake opening
of said blowing means.
12. A reflow soldering apparatus according to claim 1, wherein said
blowing means is a fan or a blower.
13. A reflow soldering apparatus according to claim 12, wherein
said fan is a turbofan or a multiblade fan.
14. A reflow soldering apparatus according to claim 1, wherein
nitrogen gas is employed as said gas.
15. A reflow soldering apparatus according to claim 1, wherein air
is employed as said gas.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a reflow soldering
apparatus using circulated heated gas to solder electronic
components to a circuit board while transporting the circuit board
mounted with electronic components on a conveyor through a heating
chamber.
[0003] 2. Description of the Related Art
[0004] The reflow soldering apparatus is a device for heating a
circuit board mounted with electronic components, melting the
soldering paste and soldering the electronic components to the
circuit board while the circuit board mounted with electronic
components is transported by conveyor chain within a heated
chamber.
[0005] A fan and a heater are installed in the reflow soldering
apparatus to perform reflow soldering of the electronic components
by heated gas. A reflow soldering apparatus of this type generally
has a plurality of preheating chambers and one reflow soldering
chamber arrayed along the transport direction of the conveyor
chain. Each preheating chamber and reflow soldering chamber is
installed with a fan and a heater. The fan and the heater are
arranged above and below the conveyor chain. The gas heated through
the heater is guided by a blow guidance means formed inside each
chamber and blown onto the printed circuit board mounted with
electronic components placed on the conveyor chain. The blow
guidance means has a nozzle plate arranged horizontally and spaced
apart from the printed circuit board on the conveyor chain. Heated
gas from a plurality of nozzle holes formed in the nozzle plate is
blown onto the printed circuit board mounted with electronic
components.
[0006] The heated gas blown onto the edge section of the printed
circuit board through the nozzle holes in the nozzle plate, heats
edge section of the printed circuit board and then flows to open
spaces on the sides, so that gas heated to a specific temperature
is constantly blown onto the edge section of the printed circuit
board. However, after the heated gas blown onto the center section
of the printed circuit board through the nozzle holes in the nozzle
plate, heats the center section of the printed circuit board, this
heated gas is not prone to flow to the open spaces on the sides,
and tends to remain in that vicinity. As a result, a temperature
difference occurs between the edge section of the printed circuit
board and the center section of the printed circuit board, causing
the problem of uneven distribution of heating temperatures.
SUMMARY OF THE INVENTION
[0007] In view of the above problems with the related art, the
present invention has the object of providing a reflow soldering
apparatus to render a smooth flow of heated gas so that the
distribution of heating temperatures on the circuit board mounted
with electronic components can be uniform.
[0008] To resolve the above mentioned problem with the related art,
the present invention employs the following means. Namely, a reflow
soldering apparatus using circulated heated gas to solder
electronic components to a circuit board while transporting the
circuit board mounted with electronic components on a conveyor
through a heating chamber, comprises a plurality of gas passages
formed at intervals along the transport direction of the conveyor,
said gas passage having an opening for inflow of heated gas on the
side facing the circuit board, and a first passage for the flow of
heated gas into a blowing means from an opening different from the
opening for inflow and formed in an intermediate portion of the gas
passage.
[0009] The heated gas blown onto the circuit board mounted with
electronic components, flows into the gas passage from the opening
facing the circuit board side, and flows smoothly into the blowing
means from the opening formed in the intermediate portion of the
gas passage.
[0010] The present invention preferably has a second passage
besides the first passage. In other words, the present invention
preferably has a second passage for the flow of heated gas into the
blowing means from an opening formed in an end portion of the gas
passage.
[0011] In the present invention, after the heated gas blown onto
the circuit board mounted with electronic components, flows into
the gas passage from the opening facing the circuit board, besides
flowing into the blowing means by way of the first passage, the
heated gas also flows into the blowing means from the opening
formed in the end portion of the gas passage, so that the heated
gas is thus smoothly circulated.
[0012] The gas passage is for instance formed as a long, narrow
passage intersecting the conveyor transport direction. The gas
passage for blowing heated gas onto the circuit board is preferably
provided between gas passages for inflow of heated gas and more
preferably is formed between each of the gas passages for inflow of
heated gas. In such cases, the gas passage for blowing heated gas
onto the circuit board is for instance formed as a long, narrow
passage intersecting the conveyor transport direction.
[0013] When the first passage and the second passage are provided,
a structure in which the blowing means has intake openings on both
opposite sides, and the heated gas flowing through the first
passage is drawn into one of the intake openings, and the heated
gas flowing through the second passage is drawn into the other
intake opening, can provide smooth circulation of heated gas.
[0014] In that case, preferably a structure is provided where the
blowing means has intake openings on the circuit board side and on
the opposite side, and the heated gas flowing through the first
passage from the opening formed in the intermediate portion of the
gas passage is drawn into the intake opening provided on the
circuit board side of the blowing means, and the heated gas passing
through the second passage from the opening formed in the end
portion of the gas passage is drawn into the intake opening
provided on the opposite side from the circuit board.
[0015] The blowing means having intake openings in both opposite
sides, besides being constituted by one fan or blower, may also be
constituted by combining two fans or two blowers.
[0016] The blowing means preferably has intake openings on two
sides as described above, but may also have an intake opening on
one side.
[0017] In that case, when the first passage is present, a structure
is preferably provided where the blowing means has an intake
opening on the circuit board side, and the heated gas flowing
through the first passage from the opening formed in the
intermediate portion of the gas passage is drawn into the intake
opening of the blowing means.
[0018] Further, when the first passage and the second passage are
present, a structure is preferably provided where the blowing means
has an intake opening on the circuit board side, and the heated gas
flowing through the first passage from the opening formed in the
intermediate portion of the gas passage is drawn into the intake
opening of the blowing means, and the heated gas passing through
the second passage from the opening formed in the end portion of
the gas passage is drawn into the intake opening of the blowing
means.
[0019] A fan or a blower is employed as the blowing means. A
turbofan or a multiblade fan is for instance employed for the fan.
When the fan has intake openings in both sides, the turbofan is
preferable since the thickness of the fan can be decreased.
[0020] Air or nitrogen gas and the like is employed as the gas,
however, nitrogen gas is preferable since oxidation is
prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Preferred embodiments of the present invention will be
described in detail based on the followings, wherein:
[0022] FIG. 1 is a vertical cross sectional view of the reflow
soldering apparatus showing one preferred embodiment of the present
invention;
[0023] FIG. 2 is a vertical cross sectional view showing a portion
of FIG. 1 cut at a right angle in the direction of transport;
[0024] FIG. 3 is a vertical cross sectional view showing a portion
of FIG. 1 cut along the direction of transport;
[0025] FIG. 4 is a perspective view showing the second casing
portion as seen from the opposite side from the nozzle holes;
[0026] FIG. 5 is a perspective view showing the second casing
portion as seen from the nozzle holes side;
[0027] FIG. 6A is a plan view showing the second casing
portion;
[0028] FIG. 6B is a front view showing the second casing
portion;
[0029] FIG. 7 is an enlarged view showing a portion of the end
surface of the nozzle holes side of the gas passage * forming
member;
[0030] FIG. 8 is a view corresponding to FIG. 2, showing another
preferred embodiment of the present invention; and
[0031] FIG. 9 is a view corresponding to FIG. 3, showing still
another preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] One preferred embodiment of the present invention is next
described while referring to FIG. 1 through FIG. 7.
[0033] A reflow soldering apparatus contains a long, narrow heating
oven 1. The heating chamber inside the heating oven 1 is supplied
with nitrogen gas to prevent oxidation of the solder and the
electronic components. A printed circuit board 2 mounted with
electronic components is transported into the heating chamber by a
conveyor chain 3.
[0034] The heating chamber is divided by partition walls 4 into
eight compartments, comprised of seven preheating chambers 5 and
one reflow soldering chamber 6 arranged along the direction of
transport. The preheating chambers 5 are compartments for gradually
heating the printed circuit board 2 mounted with electronic
components. The printed circuit board 2 mounted with electronic
components is heated to approximately 150 degrees centigrade in
these preheating chambers 5. The reflow soldering chamber 6 is a
compartment for melting the soldering paste and soldering the
electronic components. The printed circuit board 2 mounted with
electronic components is heated to approximately 230 degrees
centigrade in the reflow soldering chamber 6. Further, a cooling
section 7 cools the printed circuit board 2 mounted with electronic
components that have reached a high temperature after being
soldered. The cooling section 7 is arranged to adjoin the heating
oven 1.
[0035] The forward path of the conveyor chain 3 is arranged from
the entrance side of the heating oven 1 through the heating oven 1,
and extends horizontally to the cooling section 7 disposed adjacent
to the exit of the heating oven 1, and the return path of the
conveyor chain 3 is arranged below the heating oven 1. The
reference numeral 1a denotes an opening formed in the entrance wall
and exit wall of the heating oven 1. The reference number 4a
denotes an opening formed in the partition wall 4. The printed
circuit board 2 mounted with electronic components is loaded on the
conveyor chain 3 at the entrance side of the heating oven 1, and
after passing through the heating chamber, pass through the cooling
section 7 and is withdrawn afterwards.
[0036] Heated gas circulating systems of the same structure are
provided above and below the conveyor chain 3 in each chamber 5 and
6 of the heating oven 1. The following is explained on the heated
gas circulating system on the upper side.
[0037] Fans 8 are respectively installed in the upper ends of the
chambers 5 and 6 of the heating oven 1, and connected to motors 9
installed in the upper section outside of the heating oven 1. The
fan 8 has vanes above and below a steel plate 10, and has an intake
opening 11 in the upper surface and a discharge opening 12 in the
outer circumference, an intake opening 13 in the lower surface and
a discharge opening 14 in the outer circumference. A multiblade fan
or a turbofan is employed for the fan 8. In this embodiment, a
turbofan is employed and is housed in a first casing 15.
[0038] The first casing 15 is comprised of a fan storage section
15a and a gas guide section 15b. The fan storage section 15a houses
the fan 8, and has intake openings 16 and 17 in the upper and lower
surfaces facing the intake openings 11 and 13 of the fan 8. The gas
guide section 15b projects outwards on the left and right from the
left and right openings of the fan storage section 15a, and curves
downwards and has connecting openings 18 and 19 facing downwards.
The first casing 15 is a rectangle as seen from a plan view and has
almost no gap with the partition wall 4, but spaces 20 are present
between the first casing 15 and the left and right sides of each
chamber 5 and 6, and further, since the first casing 15 is located
below the upper surface of each chamber 5 and 6, a space 21 is
present between the first casing 15 and the upper surface of each
chamber 5 and 6. A heater 23 is installed in the space 20 on the
side of the first casing 15 and a space 22 below. There are no
particular restrictions on the type of heater 23 but a sheath
heater is used in this embodiment.
[0039] A second casing 24 is installed below the first casing 15.
The second casing 24 stores the gas passage forming member. In this
embodiment, the second casing 24 is comprised of a storage section
24 of a gas passage forming member and a gas guide section 24b. The
storage section 24a of a gas passage forming member is a
rectangular case as seen from a plan view and is open on the
bottom. The gas guide section 24b extends upwards from the openings
formed in the upper surface on the right and left ends of the
storage section 24a of a gas passage forming member, and has
connecting openings 25 and 26 facing upwards. The connecting
openings 18 and 19 of the first casing 15 connect to the connecting
openings 25 and 26. The second casing 24 has almost no gap with the
partition wall 4, but the spaces 22 are present between the second
casing 24 and the right and left sides of each chamber 5 and 6.
[0040] The gas passage forming member 28 is stored in the second
casing 24. The gas passage forming member 28 is formed of plate
member in a corrugated shape. The gas passage forming member 28 is
comprised of an array of a plurality of vertical walls 28a placed
at intervals in the direction of transport of the conveyor chain 3,
and roof walls 28b with generally inverse V-shaped cross section
which connect to the upper edges of the adjoining vertical walls
28a, and nozzle forming walls 28c with generally V-shaped cross
section which connect to the lower edges of the adjoining vertical
walls 28a. The roof wall 28b and nozzle forming wall 28c are
alternately formed in the transport direction of the conveyor chain
3. The gas passage forming member 28 is stored and fixed inside the
second casing 24 in such a way that the upper edge is positioned
slightly upward from a level upper surface 29 of the intermediate
portion of the second casing 24. The intermediate portion of the
gas passage forming member 28 is therefore notched from the roof
wall 28b to the upper edge of the vertical wall 28a, to match the
level upper surface 29 of the intermediate portion of the second
casing 24 and tilted surfaces 30 of the gas guide section 24b, and
the gas passage forming member 28 is formed with a plurality of
long, narrow openings 31. The second casing 24 is also formed with
a plurality of long, narrow openings 32 of the same shape adjoining
the plurality of long, narrow openings 31.
[0041] A plurality of nozzle holes 33 are formed at intervals in
the longitudinal direction in the bottom surface of the nozzle
forming wall 28c. A long, narrow space which is formed by the
vertical walls 28a and the nozzle forming wall 28c of the gas
passage forming member 28 forms a gas passage 34 for blowing heated
gas onto the printed circuit board 2 mounted with electronic
components. A long, narrow space which is formed by the vertical
walls 28a and the roof wall 28b of the gas passage forming member
28 forms a gas passage 35 for inflow of the heated gas. The gas
passage forming member 28 extends to the left and right sides of
the second casing 24 and forms the lower fringe of the side surface
of the second casing 24, the left and right ends of the gas passage
34 for blowing the heated gas onto the printed circuit board 2 are
sealed off, and the left and right ends of the gas passage 35 for
inflow of the heated gas are open.
[0042] The heated gas circulating system above the conveyor chain 3
was described, however, the heated gas circulating system below the
conveyor chain 3 is configured in the same way.
[0043] The function of the invention is described next.
[0044] The printed circuit board 2 mounted with electronic
components is loaded onto the conveyor chain 3 at the entrance to
the heating oven 1, and transported into the heating chamber by the
conveyor chain 3. In the reflow soldering chamber 6 and the
preheating chamber 5, each fan 8 is rotated by the motor 9.
[0045] The following is explained based on the heated gas
circulating system in the upper portion.
[0046] The heated gas from the fan 8 flows through the gas guide
section 15b of the first casing 15 and enters the second casing 24
from the left and right connecting openings 18 and 19. The heated
gas which entered the second casing 24 through the gas guide
section 24 is blown onto the printed circuit board 2 mounted with
electronic components on the conveyor chain 3, from the nozzle
holes 33 of the gas passages 34.
[0047] After the heated gas blown onto the printed circuit board 2
mounted with electronic components has heated the printed circuit
board 2 with electronic components, the heated gas flows into the
gas passages 35 from the openings 35a facing the printed circuit
board 2. The heated gas that has flown into the gas passages 35,
besides passing through the first passage and being drawn into the
intake opening 13 on the lower surface of the fan 8, passes through
the second passage and is drawn into the intake opening 11 on the
upper surface of the fan 8. In other words, in this embodiment, the
heated gas that flowed into the gas passages 35, passes through the
openings 31 formed in the intermediate portion longitudinally in
the gas passages 35 and the openings 32 of the second casing 24,
and flows out into the space 27 below the fan 8, and is drawn into
the intake opening 13 on the lower side of the fan 8. The heated
gas flowing into the gas passages 35 on the other hand, flows out
to the spaces 22 from the openings 35b formed on both ends of the
gas passages 35, passes through the spaces 20 while being heated by
the heater 23 and enters the space 21 above the first casing 15,
and is drawn into the intake opening 11 on the upper side of the
fan 8.
[0048] The heated gas from the fan 8 then enters the second casing
24 through the gas guide section 15 of the first casing 15, and is
blown from the nozzle holes 33 onto the printed circuit board 2
mounted with electronic components to heat the printed circuit
board 2 mounted with electronic components.
[0049] The heated gas circulating system on the upper side was
described above, however the heated gas circulating system on the
lower side has the same effect.
[0050] The heated gas as described above can heat the printed
circuit board 2 mounted with electronic components without the
heated gas remaining at a point and can circulate smoothly, so that
the heating temperatures are uniformly distributed on the printed
circuit board 2 mounted with electronic components.
[0051] The printed circuit board 2 mounted with electronic
components is in this way gradually heated in the preheating
chambers 5, the soldering paste is melted in the reflow soldering
chamber 6 and the electronic components on the printed circuit
board 2 is soldered satisfactorily. The printed circuit board 2
mounted with electronic components is then transported out of the
heating oven 1, its temperature gradually is lowered in the cooling
section 7, and the printed circuit board 2 mounted with electronic
components is then withdrawn.
[0052] Another preferred embodiment of the present invention is
shown in FIG. 8. The structures of the fan and heater are different
from the above embodiment, however other sections have the same as
the structure of the above embodiment.
[0053] The fan 8 of this embodiment is a multiblade fan having an
intake opening 13 only in the lower surface and a discharge opening
14a in the outer circumference. The heater 23 is installed in the
space 27 below the fan 8.
[0054] Therefore, in explaining the function of this embodiment
based on the heated gas circulating system on the upper side, the
fan 8 draws in heated gas from the intake opening 13 on the lower
surface, and as described in the above embodiment, the heated gas
enters the second casing 24 from the first casing 15, and heated
gas is blown onto the printed circuit board 2 mounted with
electronic components, from the nozzle holes 33 of the gas passages
34.
[0055] After the heated gas has been blown onto and heated the
printed circuit board 2 mounted with electronic components, the
heated gas flows into the gas passages 35 from the openings 35a
facing the printed circuit board 2. The heated gas that flowed into
the gas passages 35, then passes through the first passage and is
drawn into the intake opening 13 on the lower surface of the fan 8.
In other words, the heated gas that has flowed into the gas
passages 35, then passes through the openings 31 provided in the
intermediate portion longitudinally in the gas passages 35 and the
openings 32 of the second casing 24, flows out to the space 27
below the fan 8, and is drawn into the intake opening 13 on the
lower surface of the fan 8.
[0056] The heated gas from the fan 8 then enters the second casing
24 through the gas guide section 15b of the first casing 15, and
blown onto the printed circuit board 2 mounted with electronic
components from the nozzle holes 33 to heat the printed circuit
board 2 mounted with electronic components.
[0057] The heated gas circulating system on the upper side was
described above, however the heated gas circulating system on the
lower side has the same effect.
[0058] In the above embodiment, the heated gas as described above
can heat the printed circuit board 2 without the heated gas
remaining at certain points and can circulate smoothly, so that the
heating temperatures are uniformly distributed on the printed
circuit board 2 mounted with electronic components.
[0059] Still another preferred embodiment of the present invention
is shown in FIG. 9. This embodiment differs from the embodiment
described in FIG. 8 in the point that after heating the circuit
board, the heated gas is drawn into the fan 8 by the second
passage, as well as the first passage. Other sections have the same
as the structure of the embodiment described in FIG. 8.
[0060] In this embodiment, spaces 36 and 37 are respectively formed
between the first casing 15, second casing 24, and the left and
right sides of each chamber 5 and 6.
[0061] Therefore, in explaining the function of this embodiment
based on the heated gas circulating system on the upper side, the
fan 8 draws the heated gas from the intake opening 13 on the lower
side, as described in the above embodiment, the heated gas enters
the second casing 24 from the first casing 15, and is blown from
the nozzle holes 33 of the gas passages 34 onto the printed circuit
board 2 mounted with electronic components, loaded onto the
conveyor chain 3.
[0062] After the heated gas has been blown onto and heated the
printed circuit board 2 mounted with electronic components, the
heated gas flows into the gas passages 35 from the openings 35a
facing the printed circuit board 2. The heated gas that flowed into
the gas passages 35, as described above, then passes through the
first passage and is drawn into the intake opening 13 on the lower
surface of the fan 8. Then, in this embodiment, the heated gas that
has flowed into the gas passages 35, further flows through the
second passage and is drawn into the intake opening 13 on the lower
surface of the fan 8. In other words, the heated gas that flowed
into the gas passages 35, flows out into the spaces 22 from the
openings 35b formed on both ends of the gas passages 35, and enters
the space 27 below the fan 8 from the spaces 36 and 37 formed
between the first casing 15, the second casing 24, and the left and
right side surfaces of each chamber 5 and 6, and is drawn into the
intake opening 13 on the lower surface of the fan 8.
[0063] The heated gas from the fan 8 then enters the second casing
24 from the gas guide section 15b of the first casing 15, and is
blown onto the printed circuit board 2 mounted with electronic
components from the nozzle holes 33 to heat the printed circuit
board 2 mounted with electronic components.
[0064] The above description was based on the heated gas
circulating system on the upper side, however the heated gas
circulating system on the lower side also has the same effect.
[0065] In this embodiment, the heated gas as described above can
heat the printed circuit board 2 mounted with electronic components
without the heated gas remaining at certain points and can
circulate smoothly, so that the heating temperatures are uniformly
distributed on the printed circuit board 2 mounted with electronic
components.
[0066] The above embodiments described a reflow soldering apparatus
that performed soldering by means of circulated heated gas,
needless to say however, the present invention war can also be
applied to a reflow soldering apparatus that uses heated gas and a
far-infrared heater besides.
[0067] Although the present invention has been described with
reference to the preferred embodiments, it is apparent that the
present invention is not limited to the aforesaid preferred
embodiments, but various modifications can be attained without
departing from its scope.
* * * * *