Metal fusion bonding – Including means to apply flux or filler to work or applicator – By partial or total immersion of work or applicator into liquid
Reexamination Certificate
2002-10-01
2004-11-16
Stoner, Kiley (Department: 1725)
Metal fusion bonding
Including means to apply flux or filler to work or applicator
By partial or total immersion of work or applicator into liquid
C228S260000
Reexamination Certificate
active
06817510
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a solder bath of wave soldering systems, and more specifically, to an apparatus applied to the wave former for increasing the wave height of molten solder.
BACKGROUND OF THE INVENTION
With the continuing advances and developments of electrical manufactures, the electrical products in new generation have more developed and complicated capability to provide peoples more convenient and comfortable life. For instance, in computer industry, because the manufacture and packaging techniques of integrated circuits are promoted and matured, the high quality multimedia personal computers are widely used. The expenditure enhancement for computers and peripheral products cause the popularization and more vigorous development thereof. However, when the performances of chips are promoted, the amounts of leads to package components on the printed circuit boards (PCBs) also are continuously enhanced. Thus the layout of printed circuit boards becomes more fine and complex. And the difficulties to mount and solder components thereon are also enhanced.
In general, the key factor of the yields of mounting assembly parts onto printed circuit boards is the leads soldering procedure of components. Especially when the amounts of leads for packaging are increased and the arrangement thereof become highly concentrated, the effective reductions of defects such as bridge, dewetting, blow hole, and etc. can promote the yields of PCBs productions and reduce the failure opportunities of components. In prior art the wave soldering procedures are mainly applied to assembly printed circuit boards for furthering mass productions. And in wave soldering process, the molten solder is driven by a motor pump and forced upward into the through holes beneath the printed circuit boards which are transported obliquely to pass the soldering wave.
Please refer to
FIG. 1
, the current wave soldering system
10
is illustrated. In the wave soldering system
10
, a solder bath
12
is applied to contain molten solder, and a motor pump
14
mounted beside the solder bath
12
can rotate its fan blades to drive the molten solder. The molten solder gushed upwards from a wave former
16
disposed in the solder bath
12
forms the rising solder wave. And printed circuit boards
20
can be transferred above the solder bath
12
through inclined transport rails
18
. Thus the rising solder wave can fill into the through holes beneath the printed circuit boards to solder the leads of components. It is noted that in the wave soldering procedure the printed circuit board
20
is disposed onto a carrier formed of aluminum alloy or fiberglass wherein the carrier has some hollows for exposing the soldering areas of the printed circuit board. Then the finger
22
chained beneath the transport rails
18
can grab two side of the carrier to transfer the printed circuit board
20
via the transport rails
18
.
In general, the printed circuit board
20
is coated flux and preheated first in the front part
24
of the transport rails
18
. The flux is applied to clean the surfaces of the soldering metal and to avoid rustiness in atmosphere at high temperature. Besides, the flux is also applied to spread thermal energy uniformly for enhancing the performance of the soldering points. The typical flux coating procedures include foaming type, spraying type, and soaking type. As to the subsequent preheat procedure is applied to dispel the volatility parts of the flux for promoting the temperatures of the printed circuit boards to enhance the flux activity and to prove the capability of filling molten solder into through holes. The typical preheating procedure is to apply infrared tubes beneath the carriers to illuminate the printed circuit boards for getting the predetermined temperature.
Please refer to
FIG. 2
, the lateral view of the solder bath
12
in wave soldering procedure is shown. The molten solder gushed upwards from the wave former
16
reflows downward along the sidewalls of the solder bath
12
, and then is retrieved in the recycled trough around the solder bath
12
. As to the carrier
26
containing the printed circuit board
20
can pass the solder wave of molten solder
24
via the inclined transport rails. Thus the molten solder can fill the through holes beneath the printed circuit board
20
to form solder points.
It is noted that in the typical wave soldering system the height of solder wave can not exceed 12 mm, so when this type of system is applied to soldering the printed circuit board with components mounted on both sides thereof, the rising molten solder is incapable of full filling the through holes of the printed circuit boards. Especially this type of printed circuit board
20
with components both sides usually has a large thickness, so the through holes formed therein also have large depths. And relatively, the carrier
26
applied to contain this type of printed circuit board
20
also has a large depth to effective protect the components thereon.
Therefore the yields of wave soldering procedures will be reduced amplitudely. Especially when the component
21
mounted on the first side of the printed circuit board
20
has a large height, the total height of the component
21
and carrier
26
is too large to effective fill the through hole from the second side of the printed circuit board
20
. Thus the defects such as voids and broken circuits usually occur at the soldering points.
In prior art the rotation rate of the motor is increased to have higher soldering wave for the thick printed circuit board in wave soldering procedure. However in practical manufacturing process, the motor pump operated at high rotation rate is unstable and usually make turbulence in the molten solder. Thus the yield of wave soldering is becoming unstable. For solving this issue, the soldering furnace
30
as shown in
FIG. 3
is introduced to soldering the thick printed circuit boards. The overflow of molten solder in solder bath
34
of the soldering furnace
30
can be controlled via adjusting the buttons on the control planet
32
. The operators then put the printed circuit boards by hands on the solder bath
34
to perform the soldering procedure.
However due to the solder bath
34
is exposed out of soldering furnace
30
, the air pollution is serious in soldering procedures and easy injure the operators. Beside when the numerous component leads are highly concentrated arranged, short circuits usually occur and reduce the quality of soldering points. Further, it is necessary to transfer the printed circuit board with large height out of the wave soldering production line first; and then to have the soldering procedures with soldering furnaces. Therefore the throughput is decreased and much cost and man effects are required to measure the printed circuit boards. So how to increase height of soldering wave and to keep the stability of soldering wave is a momentous issue for the integrated circuit packaging industry.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide a block board mounted onto the enclosing walls of the wave former to increase the height of enclosing walls and to make higher solder wave.
Another purpose of the present invention in to provide a gland mounted on the wave former to press the molten solder for increasing wave height of the molten solder.
Further a purpose of the present invention in to provide an apparatus applied to the wave soldering system for providing higher and stable molten solder wave.
The present invention discloses an apparatus applied to the wave soldering system for increasing wave height of molten solder. The wave soldering system comprises the following elements. A solder bath is applied to contain molten solder. A motor pump is disposed besides the solder bath having fan blades extended into the solder bath for driving the molten solders upwardly. A wave former is disposed in the solder bath to gush the molten solder upwardly to form solder wave. A block board is mounted along top edges of enclosing walls of
Chen Yo-Chang
Wang Po-Hung
AsusTek Computer Inc.
Birch & Stewart Kolasch & Birch, LLP
Stoner Kiley
LandOfFree
Apparatus for increasing wave height of molten solder in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for increasing wave height of molten solder in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for increasing wave height of molten solder in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3303249