Nozzle structure for air flow soldering/desoldering

Nozzle structure suitable for bringing heated fluid into contact with a plurality of terminals of a modular electronic component to facilitate attachment of the component to a substrate or removal therefrom. The nozzle structure comprises a conduit forming member engageable with the component and with the substrate to form a heated fluid conduit extending around the periphery of the component, and a heated fluid delivery conduit coupled to the conduit forming member for delivering heated fluid to the heated fluid conduit to effect melting of solder or the like at the terminals of the component.

The present invention relates to nozzles, and in particular to improved 
nozzle structures suitable for bringing heated fluid into contact with the 
terminals of modular components to facilitate attachment of the components 
to a substrate or removal therefrom. 
BACKGROUND OF THE INVENTION 
Devices for attaching modular electronic components to or removing them 
from a substrate, such as a printed circuit board, are well known. Present 
day devices for removing or installing modular eletronic components from a 
substrate such as a printed circuit board generally fall into two 
categories, namely those which use a heated head which contacts each 
terminal to melt the solder thereon, or those which use a blast of hot air 
to melt the solder. In the latter devices, the blast of hot air is 
directed towards the terminals from a source above the components to 
simultaneously melt the solder on each of the terminals. An example of 
such a device is set forth in U.S. Pat. No. 4,366,925. Such a device may 
function satisfactorily if there is a large spacing between the components 
on the printed circuit board, such that the blast of hot air directed at 
one component from above will not flow over and melt the solder on the 
terminals of adjacent components. However, as the printed circuit board 
art advances, not only are the components themselves becoming increasingly 
smaller, but their proximity on the printed circuit board is also 
increasing. Thus, there is a need for a device which not only can provide 
a closely controlled and evenly distributed source of heat effective to 
melt the solder associated with the component terminals or printed 
substrate conductors during installation or removal of the electronic 
component relative thereto, but also one which can rapidly and precisely 
direct this controlled heat where desired, thereby minimizing the 
likelihood of melting the solder on the terminals of adjacent components 
or otherwise damaging the printed conductors on the substrate. 
It is therefore a primary object of the present invention to provide a 
superior device for insulation and removal of electronic components from 
circuits printed on a substrate. 
It is another object of the present invention to provide an improved nozzle 
structure for bringing heated fluid more directly into contact with the 
terminals of modular electronic components to facilitate their attachment 
or removal from a substrate. 
It is a further object of the present invention to provide an improved 
nozzle structure having means for forming a conduit extending around the 
edge of the component for accurately directing heated fluid around the 
edge of the component to effect melting of the solder at the terminals of 
the component. 
It is yet another object of the present invention to provide an improved 
nozzle structure in which the means for forming the conduit extending 
around the edge of the components is fabricated from a flexible material 
to facilitate sealing of the conduit forming means against the component 
and the substrate. 
BRIEF DESCRIPTION OF THE INVENTION 
According to one aspect of the present invention, there is provided a 
nozzle structure suitable for bringing heated fluid into contact with a 
plurality of terminals of a modular electronic component to facilitate 
attachment of the component to a substrate or removal therefrom. The 
nozzle structure comprises a conduit forming means engageable with the 
component and with the substrate to form a heated fluid conduit extending 
around the component. A heated fluid delivery means is coupled to the 
conduit forming means for delivering heated fluid to the conduit to 
thereby effect melting of solder or the like at the terminals of the 
component. 
In a preferred embodiment, the conduit forming means comprises a frame 
having a top plate and side members attached to the top plate. The top 
plate is engageable with an external surface of the component, and the 
side members are engageable with the substrate to form the heated fluid 
conduit. 
In another preferred embodiment, the conduit forming means includes a 
flexible sealing member having a first end engageable with the component 
and a second end engageable with the substrate to form the heated fluid 
conduit.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention describes alternative nozzle structures which may be 
used in the inventions described and claimed in co-pending patent 
application Ser. No. 649,065 filed Sept. 10, 1984, co-pending patent 
application Ser. No. 742,702, filed June 7, 1985, and an application 
executed by William J. Siegel and Vincent P. Barkley on Aug. 2, 1985 
entitled "HEATER DEVICE" U.S. patent application Ser. No. 762,869 filed 
Aug. 6, 1986. These applications relate to devices for attaching modular 
electronic components to or removing them from a substrate, and in view of 
the fact that the nozzle structure of the present invention may be 
utilized in those devices, the entire disclosures of those three 
applications are hereby specifically incorporated by reference into the 
present application. 
In the following description, reference may be made to air as the fluid 
being heated. However, it will be appreciated that the invention is not 
limited to the use of air, and other fluids such as inert gases, including 
nitrogen, oxygen and carbon dioxide, may be used, if desired. 
Referring now to the drawings, and in particular to FIGS. 1 through 3, 
there is shown a nozzle structure, generally referenced 2, having a 
conduit forming means 4 engageable with a component 6, and with a 
substrate 8 to form a heated fluid conduit 10 extending around the 
periphery 12 of the component 6. The nozzle structure 2 also includes a 
heated fluid delivery means 14 for delivering heated fluid from a source 
of heated fluid 16 into the heated fluid conduit 10 for effecting melting 
of solder, or the like, 18 at the terminals 20 of the component 6. 
Conduit forming means 4 is engageable with an upper surface 22 of the 
component 6, and/or with an upper surface 24 of the substrate to seal the 
conduit forming means 4 against the component 6 and the substrate 8 to 
form the heated fluid conduit 10 extending around the component 6. In the 
embodiment shown in FIGS. 1 through 3, conduit forming means 4 comprises a 
frame 26 including a top plate 28 and side members 30 attached to the top 
plate 28. As can be seen from FIG. 3, the top plate 28 is engageable with 
the upper surface 22 of the component 6 and the side members 30 are 
engageable with the upper surface 24 of the substrate to form the heated 
fluid conduit 10. 
If the conduit forming means 4 does contact the upper surface 22 of the 
component 6 and/or the upper surface 24 of the substrate, it is desirable 
to provide a heat resistant compliant coating 27 on at least a lower 
surface 29 of the top plate 28 and at a lower edge 31 of side member 30 to 
render the conduit forming means 4 more conformable with the component and 
the substrate. Any suitable heat resistant compliant material may be used, 
for example teflon or silicon. Alternatively, the conduit forming means 4 
may be designed so that it does not contact the upper surface 22 and/or 
the upper surface 24, so that a small gap (not shown) is provided between 
the conduit forming means 4 and the upper surface 22 of the component 6 
and/or the upper surface 24 of the substrate 8. In this way, heated fluid 
may flow through the conduit 10 and out through these gaps. 
The heated fluid delivery means 14 comprises at least one heated fluid 
delivery conduit 32 which is connected to the frame 26 at a location 34 
such that when the frame 26 is engaged with the component 6 to form the 
heated fluid conduit 10, heated fluid is delivered adjacent the component 
6 into the heated fluid conduit 10 so as to effect melting of solder 18 of 
the terminals 20. In the embodiment shown in FIG. 1, the top plate 28 has 
four corner areas 36, 38, 40 and 42, and two delivery conduits 32 are 
connected to the top plate 28 at alternate corner areas 36, 40. The other 
alternate corner areas 38, 42 have fluid exit means 44 which may be an 
aperture 46 or a tubular member 48 to permit exiting of heated fluid from 
the conduit 10. 
The direction of flow of heated fluid in the embodiment of FIG. 1 is 
illustrated by the arrows A, B, C and D in FIG. 2 which shows heated fluid 
entering through delivery conduit 32 and for dividing into two separate 
flows A, B, C and D respectively through the conduit 10 along the 
recpective sides of the component 6. 
The source of heated fluid 16 may be any suitable source of heated fluid, 
for example a device for producing heated air. As indicated earlier, the 
heating devices described and claimed in U.S. patent application Ser. Nos. 
649,065 filed Sept. 10, 1984, 742,702 filed June 7, 1985 and the 
application entitled "Heater Device" executed by William J. Siegel and 
Vincent P. Barkley on Aug. 2, 1985 (all incorporated by reference) may be 
used with the nozzle structure of the present invention. In light of this, 
no further discussion is provided with respect to the nature of the source 
of heated fluid 16. 
FIG. 4 shows how the nozzle structure of the present invention may be 
connected to a source of heated fluid 16, when the separation between the 
delivery conduits 32 is less than the separation between the exit means 50 
of the source 16. A flexible connecting tube 52 may be employed to connect 
the exit means 50 and the delivery conduit 32. However, it will be 
appreciated any appropriate connection means may be used to effect this 
connection. 
FIG. 5 shows an alternative configuration wherein two heat sources 16 are 
employed. An advantage arising from this configuration is that the user's 
observation of the component 6 is not obscured by the heat source 16, 
which can occur in the arrangement shown in FIG. 4. It will also be noted 
that the nozzle structure may be provided with an aperture 54 in order to 
facilitate centering of the structure over the component, as well as the 
accommodation of other pieces of apertures, e.g. a source of vacuum 53. 
Flexible sealing member 56 has a first end 58 and a second end 60, with the 
first end 58 being engageable with the component 6 and the second end 
being engageable with the substrate 8. A flexible sealing member 56 is 
provided with an anchor means 52, and this is preferably integrally molded 
with the remainder of the flexible sealing member as shown in FIG. 7. A 
clamping means 64 is provided for clamping the anchor means 62 to hold the 
flexible sealing member in the frame 66, and the clamping means preferably 
includes a master plate 68 and a holding plate 70 which are adjustably 
spaced with respect to each other by means of an adjustment means 72 which 
may be a bolt 74 threadably received in a tapped hole 76 as shown in FIG. 
7. The master plate 68 and holding plate 70 define a clamping space 78 
therebetween, and this receives and clamps the anchor means 62 of the 
flexible sealing member 56. As can be seen from FIG. 7, the anchor means 
62 is a lug 80 spaced from the first end 58 so that the master plate 68 
can be accommodated between the first end 58 and the lug 80. The lug 80 is 
clamped tightly between the master plate 68 and the holding plate 70 by 
tightening the bolt 74. Even tension can be applied to the flexible 
sealing member 56 by carefully tightening the bolts 74 spaced equally 
around the nozzle structure, shown in FIG. 6. 
FIG. 8 shows, in cross-section a view taken along the line 8--8 shown in 
FIG. 6. As can be seen, a delivery conduit 82 is connected through the lug 
80 and the first end 58 to provide access for heated fluid into the 
conduit 10. In order to accommodate delivery conduit 82, corner sections 
84 are cut away from the holding plate 70 as shown in FIG. 6. 
It will be appreciated that the nozzle structure of the present invention 
may be used for heating any type of terminals associated with modular 
electronic components. Thus, for example, FIG. 7 shows the nozzle 
structure in engagement with a leadless oomponent 6, and FIG. 8 shows the 
nozzle structure in engagement with a leaded component 7. 
FIG. 9 shows the master plate 68 and holding plate 70 as they appear in 
plan view when the flexible sealing member 56 is removed. In order to 
facilitate observation by the user of the component being removed or 
installed, and also to aid in centralizing the nozzle structure over the 
component, an aperture 86 is provided as shown in FIG. 9. 
Referring again to FIG. 7, there is shown in dotted outline the 
configuration of the flexible sealing member 56 in an unflexed 
configuration, i.e when the end 58 is not in engagement with a component 
6. In the unflexed configuration, the end 58 is disposed a distance X 
above the second end 60, whereas in the flexed condition, the first end 58 
is disposed a distance Y above the second end 60. From this, it will be 
appreciated that the flexible sealing member 56 should be capable of 
undergoing flexing to accommodate components of different thicknesses and 
components which are mounted at different heights on the substrate. In 
order to achieve a satisfactory seal between the component and the 
substrate, the flexible sealing member 56 should be flexed at least so 
that the end 58 is at a distance which is greater than X shown in FIG. 7. 
If the distance X is greater than the thickness of the component, then it 
is necessary to deform the entire flexible sealing member 56 downwards, 
which may give rise to an incomplete seal around the component. In the 
arrangement shown in FIG. 7, the end 58 comes into contact with the upper 
surface 22 of the component 6 before the second end 60 contacts the upper 
surface 24 of the substrate, and this ensures the formation of a good seal 
between the flexible sealing device and the component around the entire 
periphery of the component. Generally, the thinnest components are 
leadless components 6, such as that shown in FIG. 7, and the thickest 
components are leaded components 7, such as that shown in FIG. 8. 
FIG. 10 shows a further embodiment, which eliminates exit conduits at the 
corners 88 not occupied by the delivery conduit 32. This arrangement 
comprising two diametrically opposed delivery conduit 32 is generally 
utilized with larger components where more heated fluid is required for 
melting of the solder at the terminals. However, with smaller components 
where the same amount of heated fluid is not required, it may be possible 
to eliminate one of the delivery conduits 32, such as in the embodiment 
shown in FIG. 11. In this embodiment, heated air enters the delivery 
conduit 32 and travels in the direction of the arrows E and F around the 
periphery of the component 6 and exits in the opposite corner 90. 
The conduit 32 should be long enough to permit access of the nozzle 
structure between components without physically interfering with adjacent 
components. Thus, as can be seen in FIG. 3, it is clear that the delivery 
conduit 32 should be at least as long as the distance Z in order to enable 
the nozzle structure to be placed on the surface of the substrate without 
interfering with the component 7. 
In order to improve the rigidity of the nozzle structure 2 when attached to 
the heated fluid source 16, the upstanding tubular members 48 may be 
attached to the heated fluid source to serve as support means for the 
nozzle structure. This is illustrated with dotted lines in FIG. 3. 
From the above, it will be appreciated that the nozzle structure of the 
present invention enjoys certain advantages over the nozzle structures 
described and claimed in the applications referred to earlier and 
incorporated into the present application. In particular, the delivery 
conduits 32 facilitate direct delivery of heated fluid from the source of 
heated fluid to the area around the terminals of the component, without 
heated air being wasted in occupying the space above the component and 
away from the terminals. Thus, the nozzle structures of the present 
invention are more efficient, result in quicker melting of solder at the 
terminals, and therefore are more convenient and less costly to operate.