Focused convection reflow soldering method and apparatus
AssigneeHollis Automation, Inc.
InventorsKarl E. Bahr, Arthur V. Sedrick, Jr.
Life of this patent
Estimating the term…
Abstract
An improved solder reflow system for mass joining with solder electrical and electronic components affixed on a circuit board is provided. The system employs a combination of IR heating, recirculating forced hot air heating, and focused forced hot air heating to achieve solder reflow at throughput speeds and soldering quality not heretofore achievable.
Claims24
A solder reflow apparatus for mass joining with solder electrical and electronic components positioned on a circuit board, and comprising in combination:
- (a) a preheating zone consisting of a combination of IR heating means and convective heating means for heating said board and components to just below the solder reflow temperature, said IR heating means and said convective heat means being arranged to provide temperature ramping and stabilization thereby avoiding overheating of individual components while equalizing the temperature differences among said board and individual components;
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- (b) a solder reflow zone comprising convective heating means for directing heated gas stream across said board and components to raise the temperature of said board and components sufficient to reflow solder preforms and/or solder paste or cream thereon.
A method for mass reflow soldering electrical and electronic components positioned on the top side surface of a circuit board by heating the board and components sufficiently to reflow solder preforms, solder paste or cream thereon to electrically and mechanically join any components thereon to the board comprising the steps of:
- (a) subjecting said board and components to a combination of IR heating and convective heating whereby to raise the temperature of said board and components to just below the solder reflow temperature;
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- (b) directing a heated gas stream across said preheated board and components whereby to raise the temperature of said board and components sufficient to reflow any solder preforms, solder paste or solder cream thereon.
Solder reflow apparatus for mass joining with solder electrical and electronic components positioned on a circuit board by heating the board and components sufficiently to reflow solder preforms and/or solder paste or cream thereon to electrically and mechanically join any components thereon to the board comprising:
- (a) A preheating station consisting of:
- (i) infrared heating means for directing infra-red energy onto the components and board;
- and
- (ii) convective heating means for directing relativley low velocity heated gas stream onto the components and board to aid in levelling component temperature to prevent large differences in temperature of different sized/colored components which could arise due to radiant heat transfer only, whereby to preheat the circuit board and components to a substantially uniform temperature just below the reflow temperature of the solder;
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- (b) A reflow station comprising means for directing a relatively high velocity focused heated gas stream from at least one gas knife to raise the temperature of the board and components to above the reflow temperature of the solder whereby the reflow of the solder is accomplished.
A mass reflow soldering method for mass joining with solder electrical and electronic components populating the top side surface of a circuit board along with solder preforms and/or solder paste or cream thereon comprising the steps of:
- (a) Preheating said circuit board, solder and components by
- (i) directing radiant heat onto the board, solder and components to raise the temperature thereof towards a temperature approaching the solder reflow temperature;
- and
- (ii) directing a first, relatively low velocity heated gas stream across and around said board, components and solder whereby cooler components are heated and hotter components are cooled thereby to stabilize the components at a substantially uniform temperature slightly below the reflow temperature of solder;
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- (b) Reflowing said solder by directing a second, relatively high velocity heated gas stream as a narrow knife-edged stream against the components and board to additionally heat the top side surface of the board, solder and components to a temperature above the reflow temperature of solder, whereby to electrically and mechanically join any components thereon to the top side surface of the board.
Solder reflow apparatus for mass joining with solder electrical and electronic components positioned on a circuit board and populating the top side surface of the board by heating the top side surface of the board sufficiently with infra-red energy and hot gas to reflow solder preforms and/or solder paste or cream thereon to electrically and mechanically join any components thereon to the top side surface of the board, wherein said apparatus includes an entrance, an exit, and means for transporting a circuit board to be soldered between said entrance and said exit and comprising in combination:
- (a) a preheating zone consisting of a combination of IR heating means and convection heating means for heating said board and components to a first, substantially uniform temperature just below the reflow temperature of said solder preforms, paste or cream, said IR heating means and said convective heating means being arranged to provide temperature ramping and stabilization thereby avoiding overheating and underheating of individual components while equalizing the temperature differences among said board and said individual components;
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- (b) a solder reflow zone comprising at least one knife-edged hot gas nozzle for directing a heated gas stream onto said board and components so as to heat said board and components to above the reflow temperature of said solder.
Dependencies are inferred from the claim text.