Metal fusion bonding – Process – Plural joints
Reexamination Certificate
2002-02-19
2003-04-15
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Plural joints
C228S180210, C228S180220
Reexamination Certificate
active
06547122
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a method of mounting components on a plurality of abutted circuit boards, and more particularly, to a method of mounting components on a plurality of abutted circuit boards that requires less steel plates, components mounters, and bills of material (BOM), and artworks.
2. Description of the Prior Art
Electronic products have proven to be indispensable tools in modern life and become popular with consumers, particularly gadgets that are made extra compact and mobile such as notebooks, personal digital assistants (PDA), cellular phones, and compact disc (CD) walkmans. As a result of the reduced volume of electronic products, circuit boards used in the electronic product must also have their volume reduced. In order to reduce the volume and encompass the same components on the circuit boards, manufacturers of circuit boards mount components on a front side and a rear side of a plurality of abutted circuit boards with two component mounters. Please refer to
FIG. 1
a
and
FIG. 1
b
.
FIG. 1
a
and
FIG. 1
b
are diagrams of a prior art method for mounting components on a dual circuit board
102
. The dual circuit board
102
has a first circuit board
104
and a second circuit board
106
. The first circuit board
104
and the second circuit board
106
are abutted along a separating line L. Each of the circuit boards
102
,
104
,
106
has a front side
102
a
,
104
a
,
106
a
and a rear side
102
b
,
104
b
,
106
b.
The front side
104
a
of the first circuit board
104
abuts on the front side
106
a
of the second circuit board
106
. The first step of the method is to dispose the dual circuit board
102
in a component mounter
108
a
for mounting a plurality of components
110
a
on the front side
104
a
of the first circuit board
104
and mounting a plurality of components
110
b
on the front side
106
a
of the second circuit board
106
.
For example, 300 components
110
a
are mounted on the front side
104
a
of the first circuit board
104
, and 300 components
110
b
are mounted on the front side
106
a
of the second circuit board
106
. Therefore, the front side
102
a
of the dual circuit board
102
has a total of 600 components. Before the dual circuit board
102
is disposed in the component mounter
108
a
, a first steel plate is positioned on the front side
104
a
of the first circuit board
104
and on the front side
106
a
of the second circuit board
106
.
The first steel plate has a plurality of holes. Then, solder is applied onto the first steel plate so as to fill the holes with solder. After that, the first steel plate is removed so that a plurality of solder pads is mounted on the front side
104
a
of the first circuit board
104
and on the front side
106
a
of the second circuit board
106
. Then, the dual circuit board
102
is placed in the component mounter
108
a
and infrared rays of high temperature is used to melt the solder pads such that the components
110
a
on the front side
104
a
of the first circuit board
104
and the components
110
b
on the front side
106
a
of the second circuit board
106
are soldered.
After finishing mounting components on the front side
102
a
of the dual circuit board
102
, the dual circuit board
102
is turned over and then placed in another component mounter
108
b
for mounting a plurality of components
112
a
on the rear side
104
b
of the first circuit board
104
and mounting a plurality of components
112
b
on the rear side
106
b
of the second circuit board
106
. For example, 40 components
112
a
are mounted on the rear side
104
b
of the first circuit board
104
, and 40 components
112
b
are mounted on the rear side
106
b
of the second circuit board
106
. Therefore, a rear side
102
b
of the dual circuit board
102
has a total of 80 components. Two separate circuit boards are formed after the separating dual circuit board
102
along the separating line L.
Before the dual circuit board
102
is placed in the component mounter
108
b
, a second steel plate is positioned on the rear side
104
b
of the first circuit board
104
and on the rear side
106
b
of the second circuit board
106
. The second steel plate has a plurality of holes. Then, solder is applied onto the second steel plate so as to fill the holes with solder. The second steel plate is removed so that a plurality of solder pads is mounted on the rear side
104
b
of the first circuit board
104
and on the rear side
106
b
of the second circuit board
106
. The dual circuit board
102
is placed in the component mounter
108
b
and the high temperature of infrared rays is used to melt down the solder pads so as to solder the components
112
a
on the rear side
104
b
of the first circuit board
104
and solder the components
112
b
on the rear side
106
b
of the second circuit board
106
.
Please notice that the prior art method of mounting components on a dual circuit board
102
requires two bills of material (BOM) and two artworks corresponding to the component mounters
108
a
and
108
b
respectively. One bill of material is required when the component mounter
108
a
mounting the components
110
a
on the front side
104
a
of the first circuit board
104
and mounting the components
110
b
on the front side
106
a
of the second circuit board
106
. The other bill of material is required when the component mounter
108
b
mounting the components
112
a
on the rear side
104
b
of the first circuit board
104
and mounting the components
112
b
on the rear side
106
b
of the second circuit board
106
.
Similarly, one artwork is provided to operators for quality checking whether the components
110
a
on the front side
104
a
of the first circuit board
104
and the components
110
b
on the front side
106
a
of the second circuit board
106
are mounted in accordance with the artwork. The other artwork is provided to operators for checking whether the components
112
a
on the rear side
104
b
of the first circuit board
104
and the components
112
b
on the rear side
106
b
of the second circuit board
106
are mounted in accordance with the artwork.
However, the use of two sets of each production part increases the manufacturing cost considerably. The design of two component mounters, two steel plates, two bills of material, and two artworks increases the preparation required and also lengthens the production line.
Assume that the component mounters
108
a
and
108
b
can mount a component in one second. If the component mounters
108
a
and
108
b
work 86400 seconds each day, an expected number of products that the component mounters
108
a
and
108
b
within two days is:(1) The front side
102
a
of the dual circuit board
102
has a total of 600 components, so the component mounter
108
a
can finish 86400/600=144 semi-finished products per day.
(2) The rear side
102
b
of the dual circuit board
102
has a total of 80 components, so the component mounter
108
b
can finish 86400/80=1080 semi-finished products per day.
(3) Combined the counts from item (1) and (2), itindicates that 144*2=288 circuit boards can be finished within two days.
As mentioned above, during same given interval, the component mounting counts are significantly different between the front side and the rear side of the dual circuit board. In other words, the production rate of one side will always lag behind the other side of the dual circuit board. As a result, the prior art method has a limited maximum throughput of the circuit boards. Additionally, if there are four circuit boards, the difference between the front side and the rear side of the dual circuit board will become more significant.
SUMMARY OF INVENTION
It is therefore a primary objective of the claimed invention to provide a method for mounting components on a plurality of abutted circuit boards. The method requires less steel plates, components mounters, and bills of material (BOM), and artworks.
The numbers of components on the front side of
Acer Incorporated
Dunn Tom
Edmondson L.
Hsu Winston
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