GB2125437A - Soldering process - Google Patents

Soldering process Download PDF

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Publication number
GB2125437A
GB2125437A GB08223588A GB8223588A GB2125437A GB 2125437 A GB2125437 A GB 2125437A GB 08223588 A GB08223588 A GB 08223588A GB 8223588 A GB8223588 A GB 8223588A GB 2125437 A GB2125437 A GB 2125437A
Authority
GB
United Kingdom
Prior art keywords
solder
vapour
inert
soldering
melting point
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08223588A
Other versions
GB2125437B (en
Inventor
Wilbert Ridd George
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB08223588A priority Critical patent/GB2125437B/en
Publication of GB2125437A publication Critical patent/GB2125437A/en
Application granted granted Critical
Publication of GB2125437B publication Critical patent/GB2125437B/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B23K1/012—Soldering with the use of hot gas
    • B23K1/015—Vapour-condensation soldering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B23K1/08—Soldering by means of dipping in molten solder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/38—Selection of media, e.g. special atmospheres for surrounding the working area
    • B23K35/386—Selection of media, e.g. special atmospheres for surrounding the working area for condensation soldering
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/003—Apparatus
    • C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/3457—Solder materials or compositions; Methods of application thereof
    • H05K3/3468—Applying molten solder
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/04—Soldering or other types of metallurgic bonding
    • H05K2203/044—Solder dip coating, i.e. coating printed conductors, e.g. pads by dipping in molten solder or by wave soldering
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/08—Treatments involving gases
    • H05K2203/088—Using a vapour or mist, e.g. cleaning using water vapor

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Molten Solder (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
  • Coating With Molten Metal (AREA)

Abstract

A process for soldering components to a printed circuit board (12) includes heating the printed circuit board by thermal transfer from an inert vapour in a tank (11) so as to exclude oxygen and the board is dipped in a solder bath (16) in the inert atmosphere. This enables dip soldering without the need for pre- solder coating or solder preforms. The inert vapour is produced from an inert organic liquid, e.g. fluorinated hydrocarbons, having a boiling point above the melting point of the solder, e.g. tin/lead. <IMAGE>

Description

SPECIFICATION Soldering process This invention relates to soldering processes, and in particular to techniques wherein piece parts are soldered in an inert atmosphere.
According to one aspect of the invention there is provided a process for applying solder to a body, the process including heating the body by thermal transfer from an inert vapour to a temperature above the melting point of the solder, and dipping the body into a bath of the molten solder whilst surrounded by said inert vapour.
According to another aspect of the invention there is provided a solder coating apparatus, including a bath for receiving a quantity of solder, means for refluxing adjacent the solder a dense organic vapour having a boiling point higher than the melting point of the solder whereby the solder is maintained in a molten state.
An embodiment of the invention will now be described with reference to the accompanying drawing in which the single figure is a schematic sectional view of a solder coating apparatus.
Referring to the drawing, the apparatus includes a tank 11 for containing a dense inert vapour whereby a piece part 12, e.g. a circuit board, to be soldered is protected from the ambient atmosphere during soldering. The inert vapour is produced from an inert organic liquid having a boiling point somewhat above the melting point of the solder to be applied to the piece part.
Typically we employ fluorinated hydrocarbons having a boiling point above 2000C in conjunction with a tin/lead solder having a melting point of about 1 800C. Vaporisation of the liquid 13 is effected by a heater 14 mounted adjacent the base of the tank, a cooling element 1 5 adjacent the upper region of the tank provides a refluxing action.
The tank 1 1 also contains an inner tank or bath 16 for receiving a quality of solder 17. We prefer to employ a 60/40 tin/lead alloy but other alloy compositions can of course be used. The solder 17 placed in the bath is heated above its melting point by thermal transfer from the vapour in contact with the solder.
Soldering of a piece part, e.g. a printed circuit board, is effected by immersing the piece part in the inert vapour whereby the part is heated to the vapour temperature. The piece part; or the relevant portion thereof, is dipped into the molten solder to effect deposition. The soldered part is then removed via the inert vapour blanket and is allowed to cool.
As the piece part is degreaced by the vapour prior to soldering the use of a flux is not essential.
Preferably however an organic acid flux such as succinic acid (Butanedioic acid) is added to the fluorinated hydrocarbon. This organic acid preferably has a boiling point above 2000C and an example of a suitable organic acid is succinic acid (Butanedioic acid) which has a boiling point of 2350C. In those applications where the use of a flux is desirable we have found that the vapour is effective in the removal of post soldering flux resides thus obviating the need for a separate washing process.
The portions of the piece parts to be soldered may be pre-tinned or they may simply comprise a clean metal surface. In some applications, e.g in the fabrication of printed circuits, solder preforms may be applied to the piece part prior to soldering. But the advantage of the present invention is that by excluding oxygen in the use of the inert vapour, in many instances pre-soldered parts and solder preforms are not necessary, thus removing a process stage from the overall process.
Claims
1. A process for applying solder to a body, the process including heating the body by thermal transfer from an inert vapour to a temperature above the melting point of the solder, and dipping the body into a bath of the molten solder whilst surrounded by said inert vapour.
2. A process as claimed in claim 1, wherein said insert vapour is protected by a blanket of a second, less dense, inert vapour.
3. A process as claimed in claim 1, wherein the inert vapour includes a fluorinated hydrocarbon.
4. A process as claimed in claim 3, wherein an organic acid flux is added to the fluorinated hydrocarbon.
5. A process as claimed in claim 4, wherein the organic acid has a boiling point above 2000C.
6. A process as claimed in claim 4 or claim 5, wherein the organic acid is succinic acid.
7. A process for applying solder to a body substantially as described herein with reference to the accompanying drawing.
8. A solder coating apparatus, including a bath for receiving a quantity of solder, means for refluxing adjacent the solder a dense organic vapour having a boiling point higher than the melting point of the solder whereby the solder is maintained in a molten state.
9. An apparatus as claimed in claim 1, and which further includes means for providing said organic vapour with a protective blanket of a further, less dense, inert vapour.
10. A solder coating apparatus substantially as described herein with reference to the accompanying drawing.
11. A body such as a printed circuit board soldered by a method or apparatus according to any preceding claim.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Soldering process This invention relates to soldering processes, and in particular to techniques wherein piece parts are soldered in an inert atmosphere. According to one aspect of the invention there is provided a process for applying solder to a body, the process including heating the body by thermal transfer from an inert vapour to a temperature above the melting point of the solder, and dipping the body into a bath of the molten solder whilst surrounded by said inert vapour. According to another aspect of the invention there is provided a solder coating apparatus, including a bath for receiving a quantity of solder, means for refluxing adjacent the solder a dense organic vapour having a boiling point higher than the melting point of the solder whereby the solder is maintained in a molten state. An embodiment of the invention will now be described with reference to the accompanying drawing in which the single figure is a schematic sectional view of a solder coating apparatus. Referring to the drawing, the apparatus includes a tank 11 for containing a dense inert vapour whereby a piece part 12, e.g. a circuit board, to be soldered is protected from the ambient atmosphere during soldering. The inert vapour is produced from an inert organic liquid having a boiling point somewhat above the melting point of the solder to be applied to the piece part. Typically we employ fluorinated hydrocarbons having a boiling point above 2000C in conjunction with a tin/lead solder having a melting point of about 1 800C. Vaporisation of the liquid 13 is effected by a heater 14 mounted adjacent the base of the tank, a cooling element 1 5 adjacent the upper region of the tank provides a refluxing action. The tank 1 1 also contains an inner tank or bath 16 for receiving a quality of solder 17. We prefer to employ a 60/40 tin/lead alloy but other alloy compositions can of course be used. The solder 17 placed in the bath is heated above its melting point by thermal transfer from the vapour in contact with the solder. Soldering of a piece part, e.g. a printed circuit board, is effected by immersing the piece part in the inert vapour whereby the part is heated to the vapour temperature. The piece part; or the relevant portion thereof, is dipped into the molten solder to effect deposition. The soldered part is then removed via the inert vapour blanket and is allowed to cool. As the piece part is degreaced by the vapour prior to soldering the use of a flux is not essential. Preferably however an organic acid flux such as succinic acid (Butanedioic acid) is added to the fluorinated hydrocarbon. This organic acid preferably has a boiling point above 2000C and an example of a suitable organic acid is succinic acid (Butanedioic acid) which has a boiling point of 2350C. In those applications where the use of a flux is desirable we have found that the vapour is effective in the removal of post soldering flux resides thus obviating the need for a separate washing process. The portions of the piece parts to be soldered may be pre-tinned or they may simply comprise a clean metal surface. In some applications, e.g in the fabrication of printed circuits, solder preforms may be applied to the piece part prior to soldering. But the advantage of the present invention is that by excluding oxygen in the use of the inert vapour, in many instances pre-soldered parts and solder preforms are not necessary, thus removing a process stage from the overall process. Claims
1. A process for applying solder to a body, the process including heating the body by thermal transfer from an inert vapour to a temperature above the melting point of the solder, and dipping the body into a bath of the molten solder whilst surrounded by said inert vapour.
2. A process as claimed in claim 1, wherein said insert vapour is protected by a blanket of a second, less dense, inert vapour.
3. A process as claimed in claim 1, wherein the inert vapour includes a fluorinated hydrocarbon.
4. A process as claimed in claim 3, wherein an organic acid flux is added to the fluorinated hydrocarbon.
5. A process as claimed in claim 4, wherein the organic acid has a boiling point above 2000C.
6. A process as claimed in claim 4 or claim 5, wherein the organic acid is succinic acid.
7. A process for applying solder to a body substantially as described herein with reference to the accompanying drawing.
8. A solder coating apparatus, including a bath for receiving a quantity of solder, means for refluxing adjacent the solder a dense organic vapour having a boiling point higher than the melting point of the solder whereby the solder is maintained in a molten state.
9. An apparatus as claimed in claim 1, and which further includes means for providing said organic vapour with a protective blanket of a further, less dense, inert vapour.
10. A solder coating apparatus substantially as described herein with reference to the accompanying drawing.
11. A body such as a printed circuit board soldered by a method or apparatus according to any preceding claim.
GB08223588A 1982-08-17 1982-08-17 Soldering process Expired GB2125437B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08223588A GB2125437B (en) 1982-08-17 1982-08-17 Soldering process

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08223588A GB2125437B (en) 1982-08-17 1982-08-17 Soldering process

Publications (2)

Publication Number Publication Date
GB2125437A true GB2125437A (en) 1984-03-07
GB2125437B GB2125437B (en) 1985-12-04

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103817062A (en) * 2013-12-28 2014-05-28 刘惠玲 Method for coating preformed welding piece with coating

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1183975A (en) * 1966-06-07 1970-03-11 Metallurg D Esperance Longdoz Method and apparatus for Continuous Galvanising
GB1496398A (en) * 1974-05-24 1977-12-30 Armco Steel Corp Method of preparing a low alloy steel surface for hot dip metallic coating
GB1598570A (en) * 1977-12-23 1981-09-23 Bethlehem Steel Corp Method of treating ferrous strand by hot dip coating procedure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1183975A (en) * 1966-06-07 1970-03-11 Metallurg D Esperance Longdoz Method and apparatus for Continuous Galvanising
GB1496398A (en) * 1974-05-24 1977-12-30 Armco Steel Corp Method of preparing a low alloy steel surface for hot dip metallic coating
GB1598570A (en) * 1977-12-23 1981-09-23 Bethlehem Steel Corp Method of treating ferrous strand by hot dip coating procedure

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103817062A (en) * 2013-12-28 2014-05-28 刘惠玲 Method for coating preformed welding piece with coating
CN103817062B (en) * 2013-12-28 2015-07-08 深圳市福摩索金属制品有限公司 Method for coating preformed welding piece with coating

Also Published As

Publication number Publication date
GB2125437B (en) 1985-12-04

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19930817