GB2357258A - A wave soldering machine with means for heating liquid flux - Google Patents
A wave soldering machine with means for heating liquid flux Download PDFInfo
- Publication number
- GB2357258A GB2357258A GB9929507A GB9929507A GB2357258A GB 2357258 A GB2357258 A GB 2357258A GB 9929507 A GB9929507 A GB 9929507A GB 9929507 A GB9929507 A GB 9929507A GB 2357258 A GB2357258 A GB 2357258A
- Authority
- GB
- United Kingdom
- Prior art keywords
- circuit board
- flux
- liquid flux
- wave
- wave soldering
- 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.)
- Withdrawn
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
- B23K1/20—Preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating
- B23K1/203—Fluxing, i.e. applying flux onto surfaces
-
- 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
- B23K3/00—Tools, devices, or special appurtenances for soldering, e.g. brazing, or unsoldering, not specially adapted for particular methods
- B23K3/06—Solder feeding devices; Solder melting pans
- B23K3/0646—Solder baths
- B23K3/0653—Solder baths with wave generating means, e.g. nozzles, jets, fountains
-
- 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
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/36—Electric or electronic devices
- B23K2101/42—Printed circuits
-
- 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
- H05K3/3489—Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
A wave soldering machine comprises means for applying a liquid flux 15 to a circuit board 10 to be soldered, which includes means for heating the liquid flux, eg via a heater 16, prior to its application to the circuit board. The machine also includes means for preheating the circuit board (22, 23, fig 2), and means for applying solder to the joints to be soldered on the circuit board by passing the circuit board over a solder wave. The means for applying the liquid flux may comprise spray nozzles 12 or a flux wave. Preferably the machine is for use with flux materials that are water based or otherwise free of volatile organic compounds (VOC).
Description
1 2357258 VOLATILE ORGANIC COMPOUND FREE PLUXING APPARATUS
Field of the invention
The present invention relates to apparatus for fluxing printed circuit boards prior to wave soldering and in particular to such apparatus intended for use with flux materials that are water based or otherwise free of volatile organic compounds (VOC).
Background of the invention
In a wave soldering process, liquid flux is applied to de-oxidise the printed circuit boards and components to prepare the metallic surfaces for application of molten solder, to effect the solder joint. The liquid fluxes are proprietary blends containing acidic activators carried in a liquid flux vehicle. Conventionally, a vehicle comprising a volatile organic compound (VOC), such as isopropyl alcohol, has been chosen for its ability to perform the mobilising function, allowing the flux to be applied evenly to the circuit board, but thereafter to be very easily driven from the board by the application of heat to evaporate the VOC's.
This leaves the temperature activated 'active' components in place, while removing the liquid vehicle which would otherwise hinder the soldering process.
Conventional mobilising vehicles using VOC's have recently become a cause of environmental concern and this has driven flux suppliers and users to change to VOC free alternatives. One such alternative is water, which can adequately fulfil the mobilisation role. However, water presents the problem that it is very difficult to evaporate sufficiently prior to wave soldering. Inadequate drying prevents the temperature activated components from reaching activity and creates 'spitting' in the solder waves.
2 Current wave soldering machines typically employ three sequential process stages; namely 1. a first stage in which liquid flux is applied by foam, wave or spray; 2. a second stage in which the circuit board is preheated; the length of this stage being governed by conveyor speed in order to effect adequate drying; and 3. a third stage in which solder is applied by passing the circuit board over a wave of solder.
When using water based fluxes, it has been found that the preheating stage has needed substantial modification in order to secure adequate drying. Typically this has involved increasing the length of the preheating stage and/or introducing varying degrees of forced convection. Such modifications affect cost as well as production floor space.
Object of the invention Accordingly, the present invention seeks to provide an alternative solution to drying VOC free (typically water based) fluxes prior to solder application.
Summary of the invention
In accordance with the present invention there is provided a wave soldering machine comprising means for applying a liquid flux to a circuit board to be soldered, means for preheating the circuit board, and means for applying solder to the joints to be soldered on the circuit board by passing the circuit board over a wave of solder, characterised in that the means for applying a liquid flux to the circuit board comprise means for heating the liquid flux prior to its application to the circuit board.
3 The action of heating the liquid flux before it is applied to the circuit board minimises the amount of heat that needs to be applied to the circuit board during the preheating stage. This allows the active components to reach -5 optimum activity rapidly and enhances the spreading of the flux on the surface of the circuit board.
The incorporation of means of heating the liquid flux before it is applied to the circuit board may be used to enhance the operation of currently available spray fluxers, such as the "EconoSpray" manufactured and marketed by the present applicant. This machine provides variable frequency and duration pulses of atomised flux which is sprayed onto the board.
Brief description of the drawings
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic section representing the part of a wave soldering machine in which flux is applied to a circuit board, and Figure 2 is a schematic representation of the three stages of a wave soldering machine embodying the invention.
Detailed description of the preferred embodiments
In Figure 1, there is shown a printed circuit board 10 to which flux is to be applied. A sealed manifold assembly 14 located below the circuit board 10 is supplied with flux under pressure. The flux 15 is preheated by means of a heater 16 which is fixed to the outside of the manifold 14.
The temperature of the flux 15 is monitored by a sensor 17, such as a thermocouple, and the output of the sensor 17 is used to control the heater 16 in order to maintain the flux at a desired temperature.
4 As the printed circuit board 10 is conveyed over the manifold 14, solenoid valves 13 are opened to spray the heated flux through spray nozzles 12 onto the underside of the circuit board 10.
Spraying the heated flux 15 onto cold circuit boards 10 would negate the advantages of heating the flux 15, as the thermal mass of the boards greatly exceeds that of the relatively small amount of applied flux and the flux spray temperature would drop immediately on contact with the circuit boards 10.
To mitigate this problem the preheating stages may be arranged in different sections, with some of the sections serving to bring the circuit boards up to temperature prior to flux application. This also promotes the wetting and spreading of the flux.
In Figure 2, the circuit boards 10 are transported by a conveyor 26 past a flux spraying station 24 as shown in Figure 1. The circuit boards are heated before reaching the spraying station 24 by a first preheating section 22 and they are further heated by a second preheating section 23 after they have been sprayed with flux. Once dried by the two preheating sections 22 and 23, the circuit boards 10 are passed over a solder wave to effect soldering of the joints of the various components mounted on the circuit boards.
It should also be noted that the hot flux could be applied in a different manner, for example by a wave instead of a spray. In this case the thermal mass of the circuit boards may not pose a serious a problem and it may be possible to dispense with the preheating section 22 that precedes the flux application stage.
Claims (4)
1. A wave soldering machine comprising means for applying a liquid flux to a circuit board to be soldered, means for preheating the circuit board, and means for applying solder to the joints to be soldered on the circuit board by passing the circuit board over a wave of solder, characterised in that the means for applying a liquid flux to the circuit board comprise means for heating the liquid flux prior to its application to the circuit board.
2. A wave soldering machine as claimed in claim 1, wherein the means for applying a liquid flux to the circuit board comprises means for spraying the flux and wherein the means for preheating the circuit board comprises a first section for heating the circuit board prior to application of the flux spray and a second section for further preheating the circuit board after application of the flux spray.
3. A wave soldering machine as claimed in claim 1, wherein the means for application a liquid flux operates by means of a flux wave.
4. A wave soldering machine constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9929507A GB2357258A (en) | 1999-12-15 | 1999-12-15 | A wave soldering machine with means for heating liquid flux |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9929507A GB2357258A (en) | 1999-12-15 | 1999-12-15 | A wave soldering machine with means for heating liquid flux |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9929507D0 GB9929507D0 (en) | 2000-02-09 |
| GB2357258A true GB2357258A (en) | 2001-06-20 |
Family
ID=10866269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9929507A Withdrawn GB2357258A (en) | 1999-12-15 | 1999-12-15 | A wave soldering machine with means for heating liquid flux |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2357258A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10138555A1 (en) * | 2001-08-06 | 2003-02-20 | Seho Systemtechnik Gmbh | Soldering circuit boards involves heating flux material in flux zone to temperature corresponding to final temperature of pre-heating zone but below boiling point of flux material |
| EP2302988A3 (en) * | 2009-09-29 | 2011-05-25 | Fujitsu Limited | Method of soldering an electronic component |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5884673A (en) * | 1981-11-12 | 1983-05-20 | Tamura Kaken Kk | Soldering method |
| JPS5884672A (en) * | 1981-11-12 | 1983-05-20 | Tamura Kaken Kk | Soldering method |
| JPH01231396A (en) * | 1988-03-11 | 1989-09-14 | Senju Metal Ind Co Ltd | Soldering method for printed wiring board |
| EP0513522A2 (en) * | 1991-05-09 | 1992-11-19 | Aldo Castoldi | Process and apparatus for welding components on printed circuit plates by means of a solder bath |
| JPH11284325A (en) * | 1998-03-31 | 1999-10-15 | Aiwa Co Ltd | Method and device for soldering printed board |
-
1999
- 1999-12-15 GB GB9929507A patent/GB2357258A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5884673A (en) * | 1981-11-12 | 1983-05-20 | Tamura Kaken Kk | Soldering method |
| JPS5884672A (en) * | 1981-11-12 | 1983-05-20 | Tamura Kaken Kk | Soldering method |
| JPH01231396A (en) * | 1988-03-11 | 1989-09-14 | Senju Metal Ind Co Ltd | Soldering method for printed wiring board |
| EP0513522A2 (en) * | 1991-05-09 | 1992-11-19 | Aldo Castoldi | Process and apparatus for welding components on printed circuit plates by means of a solder bath |
| JPH11284325A (en) * | 1998-03-31 | 1999-10-15 | Aiwa Co Ltd | Method and device for soldering printed board |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10138555A1 (en) * | 2001-08-06 | 2003-02-20 | Seho Systemtechnik Gmbh | Soldering circuit boards involves heating flux material in flux zone to temperature corresponding to final temperature of pre-heating zone but below boiling point of flux material |
| EP2302988A3 (en) * | 2009-09-29 | 2011-05-25 | Fujitsu Limited | Method of soldering an electronic component |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9929507D0 (en) | 2000-02-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |