Metal fusion bonding – Process – Applying or distributing fused filler
Reexamination Certificate
2000-10-31
2003-01-28
Elve, M. Alexandra (Department: 1725)
Metal fusion bonding
Process
Applying or distributing fused filler
C228S037000, C228S260000
Reexamination Certificate
active
06510978
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a solder jet machine for soldering electronic parts already mounted on a substrate with their leads inserted thereinto by receiving a substrate subject to soldering carried in from its substrate-carrying-in side and ejecting molten solder from its solder ejecting ports to the pattern side of the substrate subject to soldering while conveying the substrate subject to soldering keeping a pattern side facing down and to a method of soldering used in the above machine.
BACKGROUND OF THE INVENTION
Solder jet machines are already known for soldering surface mount devices and discrete parts (parts having lead legs) mounted on a substrate in a mixed state by supplying the substrate subject to soldering with molten solder ejected from their jet nozzles while conveying the substrate subject to soldering.
Solder jet machines of this type includes a first jet nozzle
1
for satisfactorily supplying molten solder to a substrate P subject to soldering on which electronic parts have been mounted and a second jet nozzle
2
for removing excess molten solder from the substrate P subject to soldering to which solder has been already supplied, as shown in
FIGS. 7 and 8
.
In the above solder jet machine, the first jet nozzle
1
and the second jet nozzle
2
are connected to a duct
3
for the first nozzle and a duct
4
for the second nozzle, respectively, and both of the ducts are soaked in a solder bath
5
in which molten solder is stored.
This solder jet machine is configured by ejecting molten solder from the first jet nozzle
1
and the second jet nozzle
2
toward a path
10
for conveying a substrate subject to soldering by rotationally driving jet impellers
6
and
7
arranged to face each of the openings at one end of the duct
3
and at one end of the duct
4
, respectively.
On the upper end portion of the first jet nozzle
1
mounted is a solder wave forming plate
9
having multiple solder ejecting ports
8
provided thereon. As shown in
FIGS. 9
a
and
9
b
, the ejecting ports
8
are designed to have the same bore diameter and the same round shape and they form three rows relative to a direction A in which the substrate P subject to soldering is conveyed: a first ejecting-port row
8
A, a second ejecting-port row
8
B and a third ejecting-port row
8
C. In this solder jet machine, the wall portion surrounding each solder ejecting port
8
on the solder wave forming plate
9
is flat.
The substrate P subject to soldering have warps of various sizes caused therein when it is heated by molten solder. And in the solder jet machine of the prior art which has the above-described configuration, when the height of the pile of the molten solder ejected from the solder ejecting ports
8
A is low, there are produced some places in the pattern side of the substrate P subject to soldering and in the portions of electronic parts subject to soldering which molten solder does not touch, which means causing non-wetting.
As one of the prior art methods to deal with the problem of non-wetting, it is possible to heighten the pile of the molten solder by increasing the rpm of the jet impellers
6
and
7
. However, at the time of increasing the rpm of the jet impellers
6
and
7
, the average height of the pile of the molten solder over a time is increased, but on the other hand, the height varies with time and is likely to be unstable. And when the height of the pile of the molten solder ejected from the solder ejecting ports
8
becomes low temporarily, there may be produced some places in the pattern side of the substrate P subject to soldering and in the portions of electronic parts subject to soldering which the molten solder does not touch, which means causing non-wetting in some parts.
Alternatively, it is possible to provide a configuration which enables heightening the pile of the molten solder without increasing the rpm of the jet impellers
6
and
7
by forming each solder ejecting port
8
on the solder wave forming plate
9
in such a manner as to be allowed to project from the surface of the solder wave forming plate
9
by coining, as shown in
FIGS. 10 and 11
.
However, although the pile of the molten solder can be heightened without increasing the rpm of the jet impellers
6
and
7
, there still arises a problem that a satisfactorily stable height of molten solder wave cannot be obtained only by forming each solder ejecting port
8
in such a manner as to be allowed to project upwardly. Specifically, the wave of the molten solder ejected from the first ejecting-port row
8
A is disturbed by the molten solder ejected from the third and the second ejecting-port rows
8
C and
8
B and becomes unstable, which causes the soldering defect that permits the molten solder to run onto the component side of the substrate P subject to soldering which has been carried in the solder jet machine.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a solder jet machine and a method for soldering which enable obtaining a molten solder wave of stable height.
In order to attain the above object, the solder jet machines according to the present invention is characterized by: forming a wall portion surrounding each solder ejecting port in such a manner as to be allowed to project upwardly from the surface of the solder wave forming plate; and forming a groove portion on the surface of the solder wave forming plate around each solder ejecting port for introducing the ejected molten solder in such a direction as to be allowed to flow down.
And the method of soldering according to the present invention is characterized by: forming a wall portion surrounding each of the solder ejecting ports formed in multiple rows relative to the direction in which a substrate subject to soldering is conveyed, in such a manner as to be allowed to project upwardly from the surface of the solder wave forming plate; forming a stable solder wave by allowing the molten solder ejected from the solder ejecting ports on the downstream side relative to the substrate-conveying direction to flow down between the adjacent solder ejecting ports on the upstream side relative to the substrate-conveying direction and by introducing the molten solder ejected from the above solder ejecting ports in such a direction as to be allowed to flow down via groove portions formed around the above solder ejecting ports; and soldering the substrate subject to soldering using the above wave.
A solder jet machine according to the first aspect of the invention as set forth in claims is characterized by: forming the above-described solder ejecting ports in multiple rows relative to the direction in which the substrate subject to soldering is conveyed; forming the above-described solder ejecting ports in such a manner that an imaginary line which links a solder ejecting port in the row on the upstream side relative to the substrate-conveying direction and a solder ejecting port in the row on the downstream side relative to the substrate-conveying direction is sloped so that the molten solder ejected from the solder ejecting ports on the upstream side can flow down between the adjacent solder ejecting ports on the upstream side; and forming groove portions on the surface of the solder wave forming plate around at least part of the above-described solder ejecting ports for introducing the ejected molten solder in such a direction as to be allowed to flow down.
A solder jet machine according to the second aspect of the invention is characterized by: forming solder ejecting ports on the solder wave forming plate in three rows: a first electing-port row, a second electing-port row and a third ejecting-port row, in this order, from the upstream side to the downstream side relative to the direction in which a substrate subject to soldering is conveyed; configuring the solder ejecting ports and the solder wave forming plate in such a manner that at least part of the molten solder ejected from the solder ejecting ports in the third row flows down between the adjacent so
Koshi Masuo
Sugimoto Tadahiko
Todoroki Kenichirou
Elve M. Alexandra
Matsushita Electric - Industrial Co., Ltd.
Parkhurst & Wendel L.L.P.
Tran Len
LandOfFree
Solder jet machine and soldering method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Solder jet machine and soldering method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solder jet machine and soldering method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3002429