TWI556901B - Apparatus for providing an inerting gas during soldering - Google Patents

Description

Equipment for supplying inert gas during soldering

Described herein are apparatus and methods for providing an inert gas during soldering. More specifically, what is described herein is an apparatus and method for providing an inert gas when using nitrogen and/or other inert gas waves.

Workpieces such as printed wiring boards or circuit boards have increasingly smaller wettable surfaces that must be coated and bonded with solder. Typical wave soldering operations involve solder baths that can be soldered through the solder bath during transport. Conventional automatic wave soldering equipment includes fluxing devices, preheaters, and solder stations that are provided to handle printed circuit boards. The printed circuit boards are transported along a moving track or conveyor belt and their side edges are supported by grip fingers. A glidant can contact the plate with a foam or spray of a glidant. The board is then passed through a preheating zone to enable the flow aid to reduce oxides on the metal surface to be soldered. The board is then contacted with a single or multiple wave of molten solder in air or in an inerting atmosphere.

The inerting atmosphere is typically nitrogen (N ₂ ) and/or other inert gases and is often referred to as N ₂ inertization. Soft soldering in an inert gas and/or nitrogen atmosphere minimizes the formation of scum or oxide on the surface of the solder. It is known that the presence of a scum or oxide layer can cause jumps, bridges or other defects in the solder joint. The solder wave is generated by the wave soldering device during operation - the proximal end is a porous tube that runs parallel to the solder wave and is used to deliver the inert gas and/or N ₂ gas to provide relative Low oxygen atmosphere, especially under the workpiece to be soldered.

Regarding lead-free wave soldering, the value of the inerting atmosphere containing N ₂ is further improved for the following reasons. The processing temperatures using conventional lead-free solders are significantly higher than the processing temperatures of conventional tin-lead solders due to the increased melting point of conventional lead-free solders. This increase in processing temperature contributes to the formation of scum. Moreover, the cost of lead-free solder is generally much higher than the cost of conventional tin-lead solder, and the economic loss associated with solder waste due to scum formation is more pronounced than that of lead-free wave soldering. In addition, the wettability of lead-free solders is inherently inferior to conventional tin-lead solders. Therefore, the quality of the solder joint formed is more sensitive to the oxidation state on the surface of the lead-free solder.

It is well known that inertization during wave soldering significantly reduces scum formation on the surface of the molten solder. Reducing scum formation not only saves solder and reduces maintenance requirements, but also improves solder wetting and ensures the quality of the solder joints formed. In order to apply an inerting atmosphere to current wave soldering machines, a common method is to insert a cage-like protective housing with an internally mounted diffuser into the molten solder reservoir. An inert gas cladding can be formed across the solder reservoir, thus reducing the tendency of the solder to oxidize.

These diffusers are often made of a perforated tube to introduce an inert gas such as N ₂ and/or other inert gas into the soldering station. However, the porous tubes become susceptible to blockage by solder splashing or flux vapor condensation during the wave soldering process. Once the diffuser is blocked, the efficiency of inertization will be greatly reduced. Modern cleaning of such diffusing tubes, for example, using an ultrasonic bath filled with a cleaning solution, is extremely difficult and time consuming. The cleaning of these tubes must be carried out regularly and can cause physical damage to the tubes. To avoid these problems, the diffusers are typically replaced once they are blocked rather than being cleaned. This increases the overall cost of the end user.

Accordingly, in order to facilitate the application of inertization by N ₂ and/or other inert gases during wave soldering, we desire at least one or more of the following devices, methods, or both. First, we intend to reduce the consumption of N ₂ or other inert gases used to inertize the production scale solder sump to, for example, but not limited to, 12 cubic meters per hour (m ³ /hr) for the inerting apparatus and method. Or smaller to meet the cost benefits of applying this technology. Secondly, it is desirable for the inerting apparatus and method to reduce the O ₂ concentration above the surface of the molten solder to, for example, but not limited to, 2500 parts per million (ppm) or less, or 2000 ppm or less. This is equivalent to the case where no board is mounted above the solder bath. Thirdly, we intend to use equipment that is easy to set up and that still minimizes the cost of trimming for the inerting equipment and method. Furthermore, it is desirable for the apparatus or method to reduce or avoid clogging of the porous diffuser to ensure stable and long lasting inertization performance.

The apparatus and method described herein can accomplish at least one or more of the purposes of inerting with nitrogen and/or other inert gases, which may be Similar methods and equipment used before are more cost effective and more user friendly.

In a particular embodiment of the invention, an envelope contains one or more diffuser tubes. In other embodiments of the invention, one or more diffuser tubes are supported over an envelope to provide an inert gas over the waves of a solder bath. In a particular embodiment, the encapsulation is in the form of a bottle and defines an internal volume. In operation, at least a portion of the envelope, such as, for example, the base and the lower portion of the neck, is immersed in a solder reservoir. The envelope additionally has a neck extending to an opening and a cover adjacent the opening. A diffuser tube contained within the envelope, for example within the base of the envelope, has an inert gas flowing therethrough. The inert gas passes through the opening of the diffuser tube and into the inner volume of the envelope. The inert gas then passes through the neck and exits the opening in the atmosphere that causes the inert gas to be directed to above the solder reservoir. In some embodiments, at least a portion of the envelope, the neck, the lid, or a combination thereof can comprise a non-stick coating or material. In a particular embodiment, the at least one diffusion tube that is enclosed comprises the central diffusion tube or a diffusion tube that is stored between the solder waves. In an alternative embodiment, three diffuser tubes are used in the solder reservoir and all three diffuser tubes are closed. In other embodiments, one or more diffusion tubes are supported above an envelope that is attached or substituted for those contained within the enclosure. In such embodiments, the inert gas flows into the envelope and up through a hollow leg or tube for supporting a diffuser (gas distribution tube) above the solder bath. The inert gas then flows from the hollow leg or tube into the diffusion tube (gas distribution tube), and then through the diffusion tube (gas distribution tube) and flows out through the perforations to enter the space above the solder bath. These embodiments are particularly suitable for use in solder waves There is a narrow space between them or a situation where solder waves overlap. In some such other or other embodiments, the encapsulated material comprises titanium to prevent the encapsulating material from being dissolved by the molten solder.

In some embodiments of the invention, an envelope is provided for supplying an inert gas during soldering of the workpiece, the encapsulation comprising: a base comprising an interior volume in fluid communication with the source of inert gas, comprising a portion with the base An internal volume in fluid communication with the interior volume and a neck of an opening, a cover adjacent the opening, and a tubular member including one or more openings for the inert gas to flow through, wherein the tubular member is present in the base and is inert to the gas The source is in fluid communication; wherein the inert gas passes through the tube into the internal volume of the base and exits through the opening.

In a further embodiment of the invention, there is provided an encapsulation for providing an inert gas during soldering of a workpiece, comprising: a base comprising an internal volume in fluid communication with a source of inert gas, one or more support legs, The support foot has an internal volume in fluid communication with the base, and a diffuser tube in fluid communication with the one or more support feet having an internal volume and including one or more perforations through which the inert gas flows Wherein the diffusion tube (gas distribution tube) is supported by the one or more support legs, and wherein the inert gas flows through the internal volume of the base, through the internal volume of the one or more support legs, into the diffusion tube The internal volume of the gas distribution tube and one or more perforations that exit the diffusion tube.

In another embodiment of the present invention, there is provided an apparatus for providing an inert gas during soldering of a workpiece, the apparatus comprising: at least one recess in the bottom of the apparatus, the at least one recess for placing in a solder reservoir At least one An edge, wherein the solder reservoir contains molten solder and at least one sidewall of the recess and at least one wall of the device defines a pod outside the solder reservoir; at least one opening in the top surface of the device, from the solder reservoir Transmitting at least one solder wave through the at least one opening and touching the workpiece; and one or more tubes including one or more openings, the one or more tubes being in fluid communication with an inert gas source, wherein at least one of the tubes The device is stored in the chamber; wherein the device is placed above the solder storage tank and under the workpiece to be soldered to form an atmosphere.

In another embodiment of the present invention, a method for providing an inerting atmosphere for workpiece wave soldering is provided, the method comprising: providing a wave soldering machine comprising: a solder storage tank containing molten solder, at least a nozzle and at least one pump that passes at least one solder wave from the molten solder bath upwardly; placing a device on top of at least one edge of the solder reservoir, wherein the device includes at least one opening on the top surface, The solder sump has at least one groove on top of at least one edge and a plurality of tubes including one or more openings, the plurality of tubes being in fluid communication with an inert gas source, wherein the workpiece and the top surface of the molten solder define an atmosphere; Passing the workpiece along a path such that at least a portion of the workpiece touches at least one solder wave emitted through the opening of the device; and introducing inert gas into the atmosphere through the one or more tubes, wherein at least one tube is stored in the envelope Where the envelope comprises: a base comprising an internal volume in fluid communication with the source of inert gas; comprising an internal volume and a base a neck of the fluidly connected opening; and a cover adjacent the opening, wherein the tubular member stored in the envelope is encased within the base; and wherein the inert gas passes through the tubular member into the inner volume of the envelope and passes through Neck and lid defined The opening enters the atmosphere.

In another embodiment of the present invention, a method for providing an inerting atmosphere for workpiece wave soldering is provided, the method comprising: providing a wave soldering machine comprising: a solder storage tank containing molten solder, at least a nozzle and at least one pump that passes at least one solder wave from the molten solder bath upwardly; placing a device on top of at least one edge of the solder reservoir, wherein the device includes at least one opening on the top surface, The solder sump has at least one groove on top of at least one edge and a plurality of tubes including one or more openings, the plurality of tubes being in fluid communication with an inert gas source, wherein the workpiece and the top surface of the molten solder define an atmosphere; The workpiece travels along a path such that at least a portion of the workpiece touches at least one solder wave emitted through the opening of the device; and the inert gas is introduced into the atmosphere through the one or more tubes, wherein at least one of the tubes is Supported above the solder wave; the base comprising an internal volume in fluid communication with the source of inert gas, and one or more attached thereto Supporting feet, each of the support legs including an internal volume in fluid communication with the base, wherein the tubular member has an internal volume in fluid communication with the one or more support feet and one or more of the inert gas flow therethrough Perforation, wherein the inert gas flows through the interior volume of the base, the internal volume passing through the one or more support legs, the internal volume entering the tubular member, and one or more perforations exiting the tubular member into the solder wave Atmosphere.

10‧‧‧Perforated tube

10’‧‧‧Diffuse tube

15‧‧‧ internal volume

20‧‧‧ hole

20’‧‧‧Perforation

30‧‧‧ Equipment

33‧‧‧ front wall of the groove

35‧‧‧ top surface

37‧‧‧The back wall of the groove

40‧‧‧ openings

43‧‧‧ side wall

45‧‧‧ Groove

47‧‧‧ side wall

65‧‧‧Inert gas source

69‧‧‧ internal volume

70‧‧‧Wave welding equipment

75‧‧‧ solder storage tank

80‧‧‧Solid solder

90‧‧‧ cover

95‧‧‧glass window

97‧‧‧ vents

100‧‧‧Workpiece

105‧‧‧Working direction

115‧‧‧ solder wave

120‧‧‧Under the workpiece

155‧‧‧Diffuser

185‧‧‧ nozzle

530‧‧‧ Equipment

555‧‧‧Perforated tube

555’‧‧‧Poly tube

555”‧‧‧Perforated tube

567‧‧‧ finger

575‧‧‧ solder storage tank

580‧‧‧Solid solder

830‧‧‧ Equipment

870‧‧‧ solder storage tank

880‧‧‧ solder storage tank

890‧‧‧ cover

895‧‧‧Inert gas inlet

897‧‧‧Ventilation exhaust line

900‧‧‧Mobile track

920‧‧‧ atmosphere above the solder tank

923‧‧‧Workpiece

925‧‧‧Workpiece orientation

930‧‧‧ Equipment

950‧‧‧ cabin

955‧‧‧Perforated tube

955'‧‧‧Perforated tube

967‧‧‧ finger

969‧‧‧Internal volume

975‧‧‧ solder storage tank

985‧‧‧ nozzle

2000‧‧‧Encapsulation

2010‧‧‧ Base

2015‧‧‧ internal volume

2017‧‧‧Inert gas source flow direction

2020‧‧‧ neck

2020" ‧ ‧ encapsulation

2025‧‧‧ internal volume

2027‧‧‧ openings

2029‧‧‧Inert gas flow direction

2030‧‧‧ cover

1040‧‧‧Diffuser tube

1050‧‧‧ solder wave

1020‧‧‧ gas supply pipeline

1010‧‧‧ base

1030‧‧‧Support feet

1060‧‧‧Perforation

Figure 1 provides an isometric view of one embodiment of a diffuser tube, the diffuser tube Contains pores or porous tubes as described herein.

Figure 2a provides an exploded isometric view of one embodiment of a diffuser tube comprising pores or a porous tube as described herein and additionally comprising an envelope and a lid.

Figure 2a' provides an exploded isometric view of one embodiment of a diffuser tube comprising pores or a porous tube as described herein and comprising an envelope and a lid, and the neck portion of the envelope additionally comprises One or more holes.

Figure 2b provides an assembled isometric view of the embodiment shown in Figure 2a.

Figure 2c provides a side exploded view of the embodiment of Figure 2a.

Figure 2d provides a side exploded view of the embodiment shown in Figure 2a'.

Figure 3a provides a top view of one embodiment of the envelope or protective outer cover containing a central diffuser tube enclosed in a bottleneck enclosure with a top cover.

Figure 3b provides an isometric view of a particular embodiment of the apparatus described herein and illustrated in Figure 3a.

Figure 3c provides a side view of a particular embodiment of the apparatus described herein and illustrated in Figure 3a, wherein the enveloping portion of the central diffuser is immersed in the molten solder.

Figure 4a provides a side view of a particular embodiment in which the central diffuser is closed and at least a portion is immersed in a solder reservoir.

Figure 4b provides a top view of a particular embodiment of the apparatus described herein and illustrated in Figure 4a.

Figure 5a provides a side view of a particular embodiment in which the central diffuser tube and the two side diffuser tubes are closed and at least a portion is immersed in a solder sump.

Figure 5b provides a specific embodiment of the apparatus described herein and illustrated in Figure 5a top view.

Figure 6 provides an isometric view of any of the covers that can be used in conjunction with the apparatus and methods described herein.

Figure 7 provides an end view of any of the covers that can be set up on the moving track, in the particular embodiment the workpiece travels through the moving track.

FIG. 8 provides a picture demonstrating the position of the O ₂ concentration of Comparative Example 1.

Figure 9 provides a picture demonstrating the position of the O ₂ concentration used to measure Example 2.

Figure 10 provides a side view of an embodiment 1000 in which a diffuser tube is supported above a base by one or more support legs to provide an inert gas over a solder bath having a solder wave or overlap A narrow space for solder waves.

Figures 11a, 11c, and 11e show bottom views of the diffusion holes of Figure 10. Figures 11b, 11d, and 11f show end view of the diffuser tubes of Figures 11a, 11c, and 11e.

At least one or more of the objects of the art can be accomplished by the methods and apparatus described herein for inertial protection during soldering. The apparatus and method described herein provide inertial protection during soldering, particularly those that may occur when soldering significant movements and rotations of workpieces, such as printed circuit boards, and increased oxidation of the surface of such workpieces. . It is contemplated that the apparatus and methods described herein can be used, for example, to trim existing wave soldering machines. In operation, in some embodiments, the apparatus is placed over the solder sump and below the moving track or other transport mechanism for transporting the workpiece to be soldered. One or more diffuser pipes smuggled into the apparatus are in fluid communication with an inert gas source such as nitrogen, an inert gas (eg, helium, neon, argon, neon, xenon, and combinations thereof), generating gas ( For example, a mixture of nitrogen and hydrogen comprising up to 5% by weight of hydrogen, or a combination thereof, to provide an inerting atmosphere. One of the devices and methods described herein is for reducing the concentration of oxygen (O ₂ ) in the atmosphere defined by the surface of the workpiece to be soldered and the surface of the molten solder contained in the solder reservoir, for example, but not limited to, per million 2500 parts (ppm) or less (measured when no board is mounted over the solder tank).

The apparatus and method described herein are intended to be placed on top of a solder bath containing molten solder that is maintained at or above the melting point of the solder (e.g., at most 50 ° C above the melting point of the solder). The apparatus described herein has an internal volume disposed on top of the solder reservoir for defining a workpiece to be soldered (which is transported in a direction from a moving track above the solder reservoir) and a surface of the molten solder Atmosphere. In some embodiments, the workpieces support the side edges of the device by moving the track or belt fingers and passing the fingers through the solder waves. In other embodiments, the workpieces are supported on pallets, locators or shelves when the workpieces are transported through the wave soldering machine. The solder reservoir has one or more nozzles that discharge one or more solder waves generated by the solder pump. The solder pump is typically a variable speed pump that allows the end user to control the flow of solder from the solder wave and increase or decrease the apex or peak of the solder wave to suit the processing conditions. In one or more embodiments herein, a housing or other enclosure may also be placed around the solder pump or a portion of the solder pump, and an inert gas may be supplied. The inert atmosphere that surrounds at least a portion of the pump can be created, thereby minimizing the formation of scum.

The one or more solder waves impinge on the surface of the workpiece to be soldered through one or more openings in the top surface of the apparatus described herein. During this process, the apparatus is provided with one or more diffuser tubes that include one or more openings, orifices, slots, perforations or pores, and are in fluid communication with an inert source of gas, such as N ₂ , such that The inert gas exits the atmosphere through the internal volume of the tubular member and through the openings or pores of the tubular members. In doing so, the lower surface, the leading edge, the back edge, and the side edges of the workpiece are uniformly covered by the inert gas as the workpiece passes the solder wave.

In a particular embodiment of the apparatus and method described herein, the size of the device placed on top of the solder reservoir is minimized to enhance inerting efficiency around the moving solder waves. In various embodiments, the static molten solder surface, or regions outside of the device path in the solder reservoir, may be covered by a high temperature material that can withstand the temperature of the molten solder contained in the solder reservoir.

The apparatus and method described herein include one or more diffusing tubes having an internal volume and one or more openings, which may be, but are not limited to, pores, holes, slots, vents, orifices, Perforations or other means for allowing nitrogen and/or other inert gases to pass through the internal volume of the tubular member and exit through the opening of the tubular member. In a particular embodiment, the tubes are porous and comprise an average pore size of about 0.2 micrometers (μm) or less to provide a laminar flow of inerting or N ₂ gas exiting the porous tube. In various embodiments, the tubes are in fluid communication with an inert gas source that supplies the inert gas through the internal volume of the tube, such as, for example, N ₂ and exits through the openings or pores of the tubes Enter the molten solder surface of the sump and the area defined by the transfer operation.

By enclosing at least one of the porous diffusion tubes, the apparatus described herein satisfies one or more of the art by preventing the openings or pores of the diffusion tubes from being clogged by solder splatters and flux vapor condensation. More demand. In this regard, solving the problem of the diffusion tube at the center is a difficult task because the center diffusion tube is often present between the two solder waves. Often, the distance between the two waves is about the same as the diameter of the diffuser, so that there is not enough space to accommodate an open narrow hole surrounding the protective shell of the central diffuser. One embodiment of this device solves this problem by mounting the central diffuser in an envelope. The envelope comprises a "bottleneck" profile having a lid at the top end of the neck, wherein the enveloped base is at least partially immersed in the molten solder sump and the neck portion exposes the molten solder surface, as shown in Figure 3c. The same as the embodiment. An inert gas blanket on the solder waves can be created from the opening at the top end of the enveloping neck.

In one or more specific embodiments herein, the neck of the envelope described herein includes one or more holes or other openings. The one or more holes are designed to allow solder to pass through the encapsulated neck, thereby improving solder flow in the solder reservoir, particularly when the envelope is placed between two solder waves. The holes may be circular, elliptical, square, rectangular or any other shape with the proviso that the solder can flow therethrough. Similarly, when more than one hole is used, the holes can be arranged in any arrangement, for example by horizontal lines along the length of the neck or staggered. The one or more holes can be of any size such that the goal of improving solder flow can be accomplished and depends on the overall size of the envelope. In some embodiments, the one or more holes in the enveloping neck may be between about 1/4" to about 1" in diameter, or from about 3/8" to about 7/8" in diameter. , or about 1/2" to A diameter of about 3/4".

In some embodiments of the invention, a lid is placed over the neck of the envelope to form an open space between the neck and the lid and when the inert gas exits the top of the neck It can guide its flow when opening. The lid can be detached from or detached from the neck or it can be secured to one or more points of the neck to hold the lid in place. When the cover is detached from and detached from the neck, one or more points of the cover, such as the outer cover or wall of the device, can be secured by any suitable attachment The method of holding the lid in place. For example, the cover can be attached to the neck, the wall of the device, or another surface. By one or more screws, bolts, clips, by welding or by another mechanism.

Advantages of the apparatus and method described herein include one or more of the following: 1) closing the diffuser to avoid the possibility that the tube openings are blocked by the splash solder; 2) the neck of the envelope is narrow and contains heat conduction a material that will heat up and eliminate the chance of flux vulcanization and coagulation solder solidification; 3) the encapsulated neck can, in some embodiments, be a non-stick coating or The material is coated to minimize coating caused by flux residue when in contact with the liquid flux; and 4) the neck of the envelope may be made of a diameter narrower than the base containing the diffusion tube to conform to the second solder The narrow space between the waves does not interfere with or interfere with the dynamic motion of the waves. In some embodiments, lower oxygen readings, such as, for example, less than 2000 parts per million, can be achieved by mounting at least one or more diffusion tubes in the encapsulation described herein. Wherein the oxygen measurement is performed in conjunction with the absence of a circuit board mounted over the solder bath.

In a specific embodiment, at least one of the diffusion tubes is The device is housed in a protective encapsulating base and immerses at least a portion of the encapsulant in molten solder maintained at a high temperature. In various embodiments, the portion of the enveloping neck that is closest to the base can also function like a thermal conductor to maintain the upper portion of the neck at a high temperature. In various embodiments, the encapsulated inert gas is hot due to preheating or due to heat transfer from the encapsulated base and neck, such as, for example, from about 160 ° C to about 220 ° C, or about 170 ° C to about 210 ° C, or about 180 ° C to about 200 ° C. In some embodiments, the inert gas (eg, nitrogen) is supplied to the diffusion tube at ambient temperature and heated as it passes through the envelope such that it exits the encapsulated neck at about 180 ° C to 200 ° C. . In other embodiments, the gas can be preheated. The use of hot inert gases in the wave soldering apparatus is useful for reducing solder weld defects, such as incomplete or inconsistent barrel fills. Bucket defects are caused by temperature gradients, and thermal inert gases can be used to minimize temperature gradients across the X-Y and Z directions.

In a particular embodiment, the apparatus and method described herein address the space limitations between a pair of solder balls. In this regard, the neck and lid may be reduced in size and cross-section to between about 5 and about 8 mm. The encapsulating base can have a diameter of from about 13 to about 20 mm or about 15 mm. It is understood that these dimensions can vary depending on the configuration of the wave soldering apparatus and can be enlarged or reduced. In particular, what we desire is that the height of the neck portion of the envelope can be varied depending on the size of the soldering apparatus used.

In certain embodiments comprising a central diffuser tube and one or more side diffuser tubes, only the central diffuser tube is included in the encapsulation described herein. In an alternative embodiment, the central diffuser and one or more side diffusers Installed in the envelope described in the text.

As previously mentioned, the apparatus described herein includes a housing containing one or more diffuser tubes and an internal volume. In some embodiments, the tubes can be disposed between a plurality of solder waves, on a plate inlet side of the solder sump, on a workpiece exit side of the solder sump, or a combination thereof. In some embodiments, one or more of the tubular members may additionally comprise a bottle-like envelope having an internal volume to allow inert gas to flow into and out of the diffuser, wherein at least a portion of the envelope Touched or immersed in the molten solder. The envelope further includes a neck having an opening; and a cover that allows the inert gas to flow through the neck away from the opening defined by the mouth and the cover into the atmosphere. In some embodiments, the cross-section of the lid over the opening of the enveloping neck is inverted U, V or C-shaped. In other embodiments, such as where one or more of the side diffusers (see, for example, Figure 5a) are sealed, the envelope has no lid because the inside of the apparatus provides the inert gas Enter the direction of the atmosphere defined by the device and the surface of the molten solder.

In some embodiments, at least a portion of the envelope can be a portion of a vertical wall of the device (eg, for example, an envelope for one or more of the side diffusers). One or more diffusion tubes are placed in an envelope and in the solder bath to avoid previous problems associated with prior art techniques of immersing the porous tube in the solder bath and/or directly in contact with the solder bath because the diffusion tube is Installed within the envelope, the encapsulation prevents molten solder from clogging the opening of the porous tube.

In a particular embodiment of the apparatus and method described herein, at least a portion of the base envelope, the neck, the lid, or a combination thereof comprises a non-stick coating or material. An example of a non-stick coating is a polytetrafluoroethylene (PTFE) coating, which can be found as a non-stick coating of the registered trademark Teflon® (Teflon is limited by DuPont, Delaware State, DuPont) Made by the company). In one embodiment of the apparatus described herein, the envelope comprises a base, a neck and a cover. In various embodiments, the selected non-stick coating should be maintained at or above the molten solder temperature typically used in lead-free wave soldering methods (e.g., up to about 260 ° C). In another particular embodiment, the coating comprises a non-adhesive coating Thermolon ^TM cohesionless, an inorganic (mineral based in) a coating, which system, manufactured by South Korea Co. Thermolon, and can Keep it as a whole at 450 ° C and avoid creating toxic vapors at elevated temperatures.

In the particular embodiment in which the central diffuser is stored in a bottle-like envelope having a C-shaped, U-shaped or V-shaped cover and further stored between one or more pairs of solder waves, due to the melting The continuous dynamic movement of the solder allows the flux dissolved in the solder reservoir to be in direct contact with the enveloping neck, cover or both disposed between the first and second waves. When the liquid flux on the surface of the enveloping neck and/or cover is vaporized or thermally decomposed, the solid flux residue may remain behind the surface of the enveloping neck and/or behind the lid. Thus, a non-stick coating can be applied to the encapsulating base, neck, lid or any combination thereof to reduce the time and expense of routine maintenance of the device. The non-stick coating can also be applied to at least a portion of the inner surface of the device or the inner surface of the cap for ease of cleaning.

In other embodiments, the central diffuser (gas distribution tube) is raised above the solder wave of the solder reservoir, especially when the space between the solder waves is relatively narrow, when the solder waves overlap, or when In the case of a change in the height of the solder wave. In this embodiment, one has an inert gas supply A base of an internal volume that flows through is provided. Optionally, the base may include an additional diffuser tube therein to allow the inert gas to flow through the additional diffuser tube and out into the internal volume of the base. When an additional diffusion tube is contained within the base, the inert gas may be supplied to the additional diffusion tube by either or both ends of the additional diffusion tube. When an additional diffuser tube is not included in the base, the inert gas is preferably supplied to the base at equidistant positions from both ends of the base to allow for an average flow distribution of the gas. The base includes one or more support feet or tubes attached thereto and extending vertically therethrough. The one or more support feet also include an internal volume through which the inert gas flows, the internal volume of the one or more support feet being in fluid communication with the internal volume of the base. At least a portion of the base and optionally at least a portion of the one or more support legs are immersed in molten solder contained within the solder reservoir. The central diffuser is secured to the one or more support legs and has an internal volume in fluid communication with the one or more support feet, such that the diffuser (gas distribution tube) is above the wave position of the solder wave and The solder wave passes between and surrounds the one or more support legs between the diffusion tube (gas distribution tube). In this manner, the solder can flow more freely within the solder sump and can more easily reach the outer edge of the sump. The base, the support legs, and the diffusion tube (gas distribution tube) can have various variations and a variety of varying cross-sectional shapes. For example, each may be circular, elliptical, square, square, triangular or other geometric shape, and the shape may be symmetrical, asymmetrical or irregular. The base, the support legs, and the diffuser tubes may each have the same or different cross-sectional shapes. When the cross-sectional shape of the base and the diffuser tube is circular, the base may have a diameter of, for example, about 0.25 to about 1.25 inches, or about 0.5. Up to about 1.0 inch, or about 0.5 to about 0.75 inches. Similarly, the diffuser tube can have a diameter of, for example, from about 0.125 to about 1.0 inch, or from about 0.125 to about 0.5 inches, or from about 0.125 to about 0.375 inches. The dimensions mentioned herein are for exemplary purposes only, and those skilled in the art will recognize that the dimensions of the base, support legs, and diffuser can vary widely and, among other things, the size of the solder reservoir containing them and The height of the solder wave in the sump depends on the height.

In this particular embodiment, each end of the central diffuser tube is capped or encapsulated and may include perforations, holes, slits or other openings sufficient for the passage of inert gas. The openings may be arranged in one or more rows or may have any other regular or irregular arrangement. In a particular embodiment, the openings are arranged in a single row along the bottom of the tubular member such that the inert gas flowing out of the openings is directed downwardly toward the top surface of the solder of the solder reservoir. In another embodiment, the openings are arranged in two parallel rows offset from the bottom centerline of the tubular member, each offset from about 0 to 45°, or each offset from about 30°, so that the diffuser (gas) The inert gas of the atmosphere flowing out of the molten solder entering the solder sump is guided outward and downward. In this particular embodiment, the rows of openings, such as a diagnosis, may be separated from each other by about 30 to 120 degrees, or about 60 to 90 degrees. In some embodiments, the openings may be a plurality of slits, each having a length of 3.0 to about 1.5 mm, preferably about 0.5 to about 1.0 mm long. The slits are separated by between about 0.5 and about 5 mm, preferably about 1.0 mm. The gas flow described herein through the base, the support feet, and the elevated diffuser (gas distribution tube) can vary, but is typically in the range of from about 0.5 to about 8.0 cubic meters per hour.

In still another embodiment of the apparatus and method described herein, the apparatus additionally includes a cover mounted to the moving track to form a tunnel for passage of the workpieces. The optional cover additionally includes a venting opening in fluid communication with the venting line of the soft welder to collect flux vapor from the atmosphere below the cover. In one embodiment, the optional cover is formed from a single layer of metal cover having a central bore to the mechanical venting vent line. In another embodiment, the optional cover is formed from a double layer of sheet metal and the double layer space is attached to the venting line of the furnace thereby forming a boundary gas trap. In a particular embodiment, the distance between the two metal sheets can be between about 1/8" and about 1⁄4". When a workpiece or circuit board passes under the cover, flux vapor generated in the soldering zone can be collected through the boundary well, and air surrounding the solder storage tank can also be trapped in the double layer space to ensure Good inerting properties. With respect to the absence of a workpiece or circuit board on the top of the solder reservoir, inert gas generated from one or more diffusers enclosed in the inerting apparatus as described herein can be drawn below the double layer space of the lid. Within the volume, a boundary inert gas curtain is formed to minimize the entry of air into the volume.

Figure 1 provides a specific embodiment of a porous tube or diffuser of the apparatus and method described herein. The perforated tube 10 is depicted as a cylindrical tube having an internal volume 15 that allows an inert gas such as nitrogen and/or other gases such as, but not limited to, another inert gas (eg, argon, helium, neon, etc. The hydrogen, or a combination thereof, flows through and is in communication with an inert gas source fluid (not shown). In one embodiment, the perforated tube 10 is made of stainless steel. However, materials for other porous tubes 10 are also applicable as long as the materials are not for the solder. Reactivity. The perforated tube 10 is in fluid communication with the source of inert gas through a gas conduit or other means (not shown). The perforated tube 10 additionally includes a plurality of perforations, pores or holes 20 (generally referred to herein as "perforations") that allow gas to flow from the interior volume 15 into the solder bath, the internal volume of the envelope (not shown). The surface of the molten solder (not shown) and the atmosphere defined by the workpiece to be soldered (not shown) or a combination thereof. While the porous tube 10 is shown to be cylindrical and has a circular cross section, other geometries are contemplated, such as, but not limited to, circular, square, rectangular, elliptical, and the like.

The perforations 20 are designed such that the gas flow energy, for example, is guided in a narrow manner by the circular aperture shown in the embodiment of Figure 1 and fills the full length of the solder reservoir (not shown). In another embodiment, the perforations 20 can be elongated holes or slits. In various embodiments, the perforations 20 can be truncated or angled to further introduce gas flow from the interior volume 15 into the solder bath (not shown) and/or the gap between the solder bath and the workpiece. The perforations 20 may have an average pore size of from 0.05 microns to 100 microns, or from 0.1 to 10 microns, or from 0.2 to 5.0 microns. In a particular embodiment, the perforations 20 have an average pore size of about 0.2 microns or less. The porous tube size and number of perforations 10 on the optimized, to seek to leave the porous tube of the gaseous stream in the _second N layer. In various embodiments, the layer of N ₂ and/or other inert gases is preferably minimized in order to minimize intrusion of air from the boundary of the inerted solder zone (e.g., workpiece, conveyor belt, etc.). flow.

Figures 2a, 2a', 2b, 2c and 2d provide an envelope 2000 comprising a diffuser 10' comprising two exploding isosceles views of the one or more perforations 20', an assembled equiangular angle View and two explosion side views. Such as As described herein, the closed diffuser can be used in the form of a central diffuser, one or more side diffusers, or any combination thereof. The diffuser 10' has one or more perforations 20' and is mounted to the encapsulated base 2010. The base 2010 is in fluid communication with an inert gas source (not shown) and houses the diffuser 10' and includes an internal volume 2015 that allows the source of inert gas to flow into the internal volume 2015 and into the diffuser 10' as indicated by arrow 2017. It is believed that the installation of the porous tube in the envelope minimizes the chance of the diffuser opening being blocked by the flux and solder. While the diffuser 10' and its surrounding base 2010 are shown to be cylindrical and have a circular cross section, other geometries are contemplated, such as, but not limited to, loops, squares, rectangles, ellipses, and the like. The enclosure 2000 additionally includes a neck 2020 adjacent the base 2010 and an interior volume 2025 in fluid communication with the interior volume of the base. The enclosure 2000 additionally includes a cover 2030 adjacent the mouth of the neck 2020 that defines an opening 2027 through which the inert gas flows outwardly as indicated by arrow 2029. In operation, the inert gas is passed from a source (not shown) into the internal volume 2015 of the base 2010, through the diffuser 10', through the perforations 20', and into the interior volume 2025 of the neck 2020 in the direction indicated by arrow 2029. (See Figures 2a, 2a', 2c and 2d). In some embodiments, as shown in Figures 2a' and 2d, the neck 2020 of the encapsulation 2000 can include one or more holes 2023 through which the solder can pass, thereby improving solder flow within the soldering apparatus.

Figures 3a, 3b and 3c provide top, isometric and side views, respectively, of one embodiment of the encapsulation described herein. Referring to Figures 3a and 3c, the apparatus 30 is placed on the wave soldering apparatus 70 to provide an inert gas atmosphere during the wave soldering operation. The wave soldering apparatus 70 includes a solder tank 75 containing molten solder 80, and One or more nozzles 185 that emit one or more solder waves (not shown) that are generated by a solder pump (not shown). Referring to Figures 3a through 3c, the device 30 has a top surface 35 that is removable from the remainder of the device, thereby making it easier for the end user to remove the dross. The top surface 35 additionally includes at least one opening 40 through which at least one solder wave emitted from the molten solder 80 contained in the solder reservoir 75 through the at least one opening 40 passes through the nozzle 185 and touches a workpiece that passes along a moving track (not shown). . Referring to Figures 3a through 3c, the apparatus 30 additionally includes at least one recess 45 on the bottom of the device 30 that is placed atop the edge of the solder reservoir 75. In some embodiments, device 30 can include more than one recess to allow device 30 to be placed on top of solder reservoir 75 and to place front and rear diffusers 155 outside of the solder bath regions shown in Figures 3a and 3c. Other embodiments of the apparatus described herein may only have a recess to position the front diffuser 155 outside of the solder bath area. Yet another embodiment of the apparatus described herein does not have one or more grooves but a plurality of fingers that allow the device to be placed on the solder reservoir and to place all of the diffusers in the solder bath region, for example The inside of the embodiment depicted in Figures 4a and 4b and Figures 5a and 5b. Referring again to Figures 3a through 3c, the side walls of the recess 45 and the front or rear wall 33 or rear wall 37 define a compartment in which the perforated tube 10' can be placed within the apparatus 30. The perforated tube 10' is in fluid communication with an inert gas source 65 via a pipe (shown in phantom in Figure 3a). As previously mentioned, the inert gas used in conjunction with the apparatus and methods described herein may comprise nitrogen, hydrogen, another inert gas (eg, helium, argon, neon, xenon, krypton, etc.) or a combination thereof. In some embodiments, the inert gas is preheated prior to introduction into the porous tube 10'. It is understood that the specific embodiment shown in Figures 3a to 3c can vary depending on the configuration of the soldering machine.

Referring now to Figures 3b and 3c, apparatus 30 additionally includes the melting The inner surface 69 defined by the solder surface (not shown), the workpiece (not shown), the front wall 33, the rear wall 37, and the side walls 43 and 47. Apparatus 30 further includes a diffuser tube 10' having at least one perforation (not shown) that is smuggled into the enclosure, wherein at least a portion of the base 2010 is immersed in the molten solder sump and used to The neck 2020 at the center is heated to a temperature above the melting point of the molten solder.

Figure 3b provides an isometric view of a particular embodiment of the apparatus 30 described herein. Referring to Figures 3b and 3c, the apparatus 30 is placed on the wave soldering apparatus 70 to provide an inert gas atmosphere during the wave soldering operation. The wave soldering apparatus 70 includes a solder reservoir 75 containing molten solder 80, and one or more nozzles 185 that emit one or more solder waves 115 that are generated by a solder pump (not shown). The device 30 has a top surface 35 that is removable from the remainder of the device, thereby making it easier for the end user to remove the dross. The top surface 35 additionally includes at least one opening 40 through which at least one solder wave emitted from the molten solder 80 contained in the solder reservoir 75 through the at least one opening 40 passes through the nozzle 185 and touches a workpiece that passes along a moving track (not shown). 100. Most fingers (not shown) allow the device to be placed on the solder reservoir. The perforated tube 10' is in fluid communication via a conduit to an inert gas source (not shown). As previously mentioned, the inert gas used in conjunction with the apparatus and methods described herein may comprise nitrogen, hydrogen, another inert gas (eg, helium, argon, neon, xenon, krypton, etc.) or a combination thereof. In some embodiments, the inert gas is preheated prior to introduction into the porous tube 10'. It is understood that the specific embodiment shown in Figures 3a to 3c can vary depending on the configuration of the soldering machine.

Referring to Figure 3c, or a side view of a particular embodiment of apparatus 30 as defined herein, apparatus 30 is constructed by placing grooves 45 in the illustrated solder reservoir. At least one edge of the slot 75 is placed atop the wave soldering device 70. The solder sump 75 has molten solder 80 therein. The moving track (not shown) conveys the workpiece 100 to be welded in the upward direction indicated by the arrow 105 shown. At least one or more solder pumps (not shown) are used to generate a plurality of solder waves 115 through the nozzles 185. The majority of the solder wave 115 penetrates the underside of the workpiece 100 through the opening of the device 30. The inert gas introduced into the closed porous diffusion tube is left in a chamber (not shown) outside the solder storage tank 75. In the embodiment illustrated in Figure 3c, a diffuser 155 is disposed at the inlet and outlet of the solder reservoir 75. In yet another embodiment, one or more of the diffuser tubes 10' can be oriented in a direction that is perpendicular to the direction of the solder waves (not shown). At least one of the diffuser tubes 10' is smuggled into an envelope comprising a base 2010 having an internal volume, a neck 2020 having an internal volume, and an opening 2027, and at the neck 2027 Cover 2030 near the opening. At least a portion of the envelope, such as the base 2010 and neck 2020, is immersed in the solder 80. The inert gas fills the area 120 below the surface of the workpiece 100 and the area or atmosphere shown above the surface of the molten solder 80.

Figures 4a and 4b provide side and top views of a particular embodiment of the apparatus 930 described herein, wherein a first porous tube 955, a second porous tube 955', and a central diffuser 10' are inside the solder reservoir 975, Moreover, the central diffuser 10' is housed in an envelope wherein at least a portion of the envelope is immersed in the solder reservoir 975. The device 930 has no grooves to provide the front and rear or first and second diffusers outside of the solder reservoir 975, such as those depicted in Figures 3a through 3c. Rather, device 930 has a plurality of fingers 967 that enable the device 930 to be placed atop solder reservoir 975. The display device 930 is shown to be constructed of a double wall of material, such as metal, that defines at least one compartment 950 that tampers at least one of the illustrated porous tubes, such as 955 and 955'. The workpiece 923 travels over the device 930 in the direction indicated by arrow 925 and is in contact with most of the molten solder waves emitted from the nozzle 985. Most of the porous tube and N ₂ source such as an inert gas (not shown) in fluid communication with, the sources of inert gas or an inert gas atmosphere such a N ₂ atmosphere through a tube, into the chamber 950, 930 into the double volume of material as defined in and The interior volume 969 defined by the molten solder surface, the workpiece 923, and the walls of the apparatus 930 enters the solder reservoir 975.

Figures 5a and 5b provide side and top views of a particular embodiment in which a first porous tube 555, a second porous tube 555' and a third porous tube 555" are inside the solder reservoir 575, and each of the porous tubes Enclosed in an envelope wherein at least a portion of the base of the encapsulation 2020" is immersed in the molten solder 580 and the envelope is heated to a temperature above the melting point of the solder. The device 530 has no grooves to provide the first and second diffusers outside of the solder sump region 575. Device 530 has a plurality of fingers 567 that enable the device 530 to be placed atop solder reservoir 575.

Figure 6 provides an isometric view of any cover 90 placed over the apparatus 30 and the moving track (not shown) such that the workpiece can pass therethrough. It is shown that any cover 90 has a glazing 95 that can be viewed. Any cover 90 additionally has a vent 97 that is in fluid communication with the venting line (not shown) of the soldering machine to remove any flux within the atmosphere of the soldering station.

FIG. 7 provides an embodiment of apparatus 830 that additionally includes any cover 890 on top of the solder reservoir 880 to form a tunnel for passage of workpieces (not shown) retained on the moving track 900. FIG. 7 provides an end view of device 830. In some embodiments, any cover 890 It is in fluid communication with a venting line of a wave soldering machine (not shown). Any cover 890 is constructed of a double sheet of sheet metal or other suitable material and is attached to a venting vent 897 of the furnace which forms a boundary gas trap. In some embodiments, the distance between the two lamella layers can be between, but not limited to, 1/8" to 1/4". In the particular embodiment illustrated in Figure 7, any cover 890 can include an inert gas inlet 895 in fluid communication with an inert source of gas (not shown) to further assist in the flow of flux vapor and air out of the solder joint. In some embodiments, when a circuit board passes under the cover 890, the flux vapor generated in the solder pad can be controlled through the boundary well, and the air surrounding the solder reservoir 870 can also be trapped. In the double space below the lid 890, that helps ensure a good inerting atmosphere. In the example where the solder reservoir 870 is not covered by the workpiece, the inert gas generated by the plurality of porous tubes (not shown) can be drawn into the two-layer space of the cover 890 to form a boundary inert gas curtain to allow air to pass from the external environment. The atmosphere 920 entering the solder sump 870 is minimized.

FIG. 10 provides a side view of an embodiment 1000 in which the central diffuser 1040 is above the surface of the solder wave 1050. In this embodiment the inert gas system is supplied to the base 1010 via a gas supply line 1020. Both ends of the base are encapsulated and have an internal volume through which an inert gas flows. The inert gas then flows upward through the internal volume of the support foot 1030 and into the internal volume of the diffusion tube (or gas distribution tube) 1040. Finally, the inert gas flows out and passes through the perforations (not shown) of the diffuser (or gas distribution tube) 1040 to enter the atmosphere above the molten solder surface (not shown).

Figures 11a, b, c, d, e, and f further illustrate the diffusion in Figure 10 The architecture of the device is provided by viewing the view of the diffuser (or gas distribution tube) 1040 (Figs. 11a, 11c, and 11e) from the base (not shown), and The end looks at the view of the diffuser (or gas distribution tube) 1040 (Figs. 11b, 11d, and 11f). As shown in Figures 11a and b, the perforations 1060 are arranged in a straight line along the bottom centerline of the diffuser (or gas distribution tube) 1040. In an alternative embodiment as shown in Figures 11c and d, the perforations 1060 are arranged in two rows and at an angle of 60 to the bottom centerline of the diffuser (or gas distribution tube) 1040. In still another alternative embodiment as shown in Figures 11e and f, the perforations 1060 are configured in three rows and the bottom centerlines of the diffuser (or gas distribution tube) 1040 are equiangularly spaced from each other and the outermost two rows There is a 90° interval between them.

Although the device and method have been described in detail and by reference to the specific examples and embodiments thereof, it will be apparent to those skilled in the art

Example Comparative Example 1: Initial design of the center diffuser

As shown in Figure 8, oxygen (O ₂ ) concentration measurements around the headspace of the solder bath without the board loaded over the solder bath and without the top cover (shown in Figure 6) were obtained. Referring to Figure 8, measurements are taken at the following points: point a (close to the left edge of the first solder wave); point b (close to the middle surface of the first wave); point c (between the two solder waves); point d (close to the middle surface of the second wave); and point e (close to the right edge of the second solder wave).

Evaluate the center based on the oxygen concentration measurements shown in Tables 1 and 2. Two different designs of diffusers. Table 1 is the result of the first design. In the first design, the central diffuser is enclosed within a metal protective tube. The protective tube contains a plurality of rows of open elongated holes to allow inert gas to flow and is coated by a PTFE coating to provide the non-stick properties. In Table 2, the central diffuser tube is also enclosed in a slitted and coated protective tube, but without a plurality of rows of elongated holes on its surface, the diffuser tube has two longitudinally elongated slits facing downward.

In Tables 1 and 2 above, the flow rate is provided in cubic meters per hour (m ³ /hr) and the three flow rate readings are for the left/middle/right or front/middle/back diffusers. The measured oxygen concentration is expressed as a percentage. During the oxygen measurement, the solder sump temperature was maintained at 260 ° C and two solder waves were generated and the ventilator was fully opened. As shown in Tables 1 and 2, the target levels of oxygen concentrations above 2000 ppm or 0.2% in both cases were quite large. The reason for these high oxygen readings is that the space between the two waves is too tight, so that the position of the central diffuser cannot be optimized. Perform a short-term glidant test (1 to 2 hours). It has been found that a PTFE coated protective tube can effectively reduce contamination by fluxing and soldering, but may not completely eliminate contamination because the protective tube is not heated.

Example 2: Inventive Center Diffuser Design

This example demonstrates the result of stealing the central diffuser tube in an envelope in accordance with the present invention, which is similar to that depicted in Figures 2a through 2c and is designed to reduce oxygen concentration and prevent diffuser clogging. In this experiment, the central porous tube was smuggled into an envelope and placed between two solder waves. It is believed that this configuration can avoid clogging problems by solidification of solder splatters and flux vapor condensation on the diffuser surface. As in Example 1, no oxygen or gas concentration measurements were taken over the solder reservoir. The O ₂ concentration at nine locations around the solder reservoir was measured at the position specified in Figure 9 under different N ₂ flow configurations. In the second embodiment, the positions b ₀ and d ₀ of Fig. 9 correspond to the positions b and d of Fig. 8 . During this O ₂ measurement, the solder sump temperature was maintained at 260 ° C and two solder waves were generated and fully vented through the furnace line venting device. The flow rate is provided in cubic meters per hour (m ³ /hr) and the three flow rate readings are for the left/middle/right or front/middle/back diffusers. The measured data is expressed as a percentage of oxygen concentration. As shown in Table 3, in most cases, the oxygen concentration is below the target level, such as 2000 ppm or 0.2%. In addition, no diffuser blockage was observed based on the two-day test using the flux. The results regarding the oxygen concentration measurement are provided in Table 3 below.

Example 3: Inventive Center Diffuser Design with Holes in Enveloped Neck

The oxygen diffuser was also measured along a central diffuser design having a hole in the neck of the envelope, similar to that depicted in Figures 2a' and 2d. The results were measured with a top cover and with and without a workpiece. Oxygen concentration when no workpiece is loaded It is in the expected range of approximately 2000 ppm (0.20%) and approximately 500 to 600 ppm (0.05 to 0.06%) in the presence of the workpiece. In addition, good solder flow around the central diffuser was observed.

Example 4: Scum formation - inventive center diffuser design

This example demonstrates that scum formation is reduced as a result of the central diffuser being stolen in the envelope in accordance with the present invention. The equipment was operated at a nitrogen flow rate of 6 m ³ /hr left, center and right diffuser tubes and at a nitrogen pressure of 4.0 bar. Scum formation was determined by measuring the amount of scum collected per day (6 hours of run time) with and without the workpiece and with and without the lid above the solder reservoir. The workpiece used was a board having a size of 350 mm by 450 mm. The scum collection results are shown in Table 4 below and compared to the baseline for the inert gas provided by the equipment. As shown in Table 4, scum formation was significantly reduced in most cases.

Other benefits of the apparatus and method in accordance with the present invention include reduced manufacturing and material costs, improved solder joint quality, and simplified transition to lead-free soldering techniques. Regarding manufacturing and material costs, it has been observed that solder consumption is reduced by 20 to 40%, scum formation is reduced by 40 to 90%, flux consumption is reduced by 10 to 30%, equipment maintenance is reduced by 70 to 80%, and lower rear sections are observed. Assembly board cleaning costs, reduced board defects and repairs, and higher productivity available time. Another benefit of the device disclosed herein is that it can be easily enlarged or reduced. The mold can be constructed to match solder slots of varying sizes. In particular, the enveloping neck described herein is small enough to fit into a very narrow space between two solder waves, and the entire diffuser encapsulation design can be adjusted horizontally, vertically or in two dimensions to match the intended application. .

The above has been defined for a number of different wordings. As long as the wording used in the scope of the patent application is not defined below, the broadest definition of the wording of the published and approved patent expressions printed by the artist at the time of application should be given. Furthermore, all patents, test procedures, and other documents listed in this application are fully incorporated by reference, insofar as the disclosure of the disclosure is not inconsistent with the present disclosure.

Certain embodiments and features of the invention are described using a set of numerical upper limits and a set of numerical lower limits. For the sake of brevity, only certain ranges are explicitly disclosed in this article. However, it should be understood that the range from any lower limit to any upper limit is taken into account unless otherwise stated. Likewise, ranges from any lower limit can be combined with any other lower limit to the extent that is not explicitly recited, and the range from any of the upper limits can be combined with any other upper limit to the extent that is not explicitly recited. In addition, even if not explicitly stated, a range includes every point or individual value between the endpoints. Accordingly, each point or individual value may be considered as a lower or upper limit and combined with any other point or individual value or any other lower or upper limit to list the ranges not explicitly recited. All values are indicative of "about" or "approximately" and the experimental errors and variations that would be apparent to those skilled in the art are contemplated.

Although the foregoing is directed to specific embodiments of the invention, and alternative embodiments thereof, those skilled in the art can Modification, modification and replacement without digressing the spirit and scope of their desires. The invention is intended to be limited only by the wording of the scope of the appended claims.

1040‧‧‧Diffuser tube

1050‧‧‧ solder wave

1020‧‧‧ gas supply pipeline

1010‧‧‧ base

1030‧‧‧Support feet

1060‧‧‧Perforation

Claims (11)

An apparatus for providing an inert gas during soldering of a workpiece, comprising: a base comprising an internal volume in fluid communication with a source of inert gas, a tubular member having an internal volume and containing one or the inert gas flowing therethrough a plurality of perforations; and one or more support feet, the support leg including an internal volume in fluid communication with an interior volume of the base and an interior volume of the tubular member; wherein the one or more support legs are vertically upward from the base Extending and raising the tube over a surface of molten solder contained in a solder reservoir, and at least a portion of the one or more support legs are immersed below the surface of the molten solder; An inert gas flows through the base, through the one or more support legs, into an interior volume of the tubular member, and through one or more perforations exiting the tubular member. The apparatus of claim 1, further comprising a second tubular member having an internal volume and including one or more perforations through which the inert gas flows, wherein the second tubular member is located within the interior volume of the base . The apparatus of claim 1, wherein the inert gas source is supplied to the base from an equidistant position from both ends of the base. The apparatus of claim 1, wherein the apparatus includes two support legs, and the source of inert gas is supplied to the base from an equidistant position from the two support legs. The apparatus of claim 1, wherein the perforations of the tubular member are disposed along the bottom of the tubular member such that the inert gas flows downwardly through the perforations of the tubular member to the surface of the molten solder. The apparatus of claim 5, wherein the perforations are arranged in a single row along the bottom centerline of the tubular member. The apparatus of claim 5, wherein the perforations are disposed in two rows equidistant from a bottom centerline of the tubular member, and the two rows are spaced apart by an angle of from about 30[deg.] to about 90[deg.]. The apparatus of claim 5, wherein the perforations are disposed in three rows spaced apart along the bottom of the tubular member and are equally spaced from each other, and wherein the outermost two rows are at an angle of from about 60° to about 120° Interval. The apparatus of claim 1, wherein at least one of the base, the one or more support feet, and the tubular member comprises or is coated with a non-adhesive material. The apparatus of claim 1, wherein the inert gas passes through the apparatus at a flow rate of from about 0.5 to about 8.0 cubic meters per hour. The apparatus of claim 1, wherein at least a portion of the base is immersed below the surface of the molten solder.