Senju Metal Industry Co., Ltd.

Tetsuya Okuno

Takashi Nauchi

A solder reflow furnace includes piping to supply an inert gas into the furnace to maintain an inert gas atmosphere within the furnace and a cooling zone provided next to a main heating zone. The cooling zone is provided with a gas cooling device in which printed circuit boards after soldering are cooled by an inert cooling gas which is in turn cooled indirectly by air outside the furnace so that air is prevented from flowing into the furnace.

Solder reflow furnace

A reflow furnace has a tunnel through which a conveyor for printed circuit boards passes. A plurality of pairs of panel-type blowers capable of blowing hot gas are disposed in the tunnel. The two panel-type blowers in each pair are disposed opposite one another above and below the conveyor. Each panel-type blower has an inlet and a discharge port. The discharge ports of opposing panel-type blowers partially overlap one another in the longitudinal direction of the furnace. When a printed circuit board is present between a pair of panel-type blowers, gas discharged from the discharge ports simultaneously heats both sides of the printed circuit board.

An infrared panel heater includes a housing having a gas inlet and a gas discharge opening covered by a porous metal panel. An electric heating element is disposed in the housing between the panel and the gas inlet for heating the panel for emission of infrared radiation therefrom. A plurality of spaced, parallel gas stream distributor plates are disposed in the housing between the heating element and gas inlet and are each provided with a plurality of openings forming the sole flow path for gas from the inlet to the discharge opening. The openings in each plate are uniform in diameter with the diameter of the openings in the respective plates decreasing as the plate is situated closer to the heating element so that a uniform gas distribution is achieved across the entire panel area. The outer surface of the panel may be coated with a porous ceramic infrared emitting layer. The center of the openings in adjacent plates are unaligned in the direction of gas flow and the total area of the openings in any one plate is equal to that of any other plate. The heating element may be in contact with the metal panel.

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Souka, Japan

Tetsuya Okuno