Vitronics Corporation

Walter J Hall

Russell G Shaw

J Robert Maxwell

Phillip D Bourgelais

Albert Chanasyk

Roy J Palhof

Apparatus for soldering surface mounted devices to printed circuit boards utilizing a combination of forced convection and infrared radiation. Fans are disposed in each heating zone which force gas through a heating plate which heats the air, emits infrared radiation for heating of printed circuit boards, and establishes a flow pattern for the gas. Flows are controlled in each zone by selectively introducing unheated gas into each zone, and by selectively exhausting gas from each zone. The volume of gas introduced and exhausted from each zone can be controlled. Closures are provided in the return channels to the low pressure side of the fan for controlling the volume of gas recirculated from the conveyor. Flow is controlled such that cooler air is always introduced into the zones which have a lower temperature and is exhausted from zones which have higher temperatures. As a consequence, the gas flow between zones can be controlled to maintain desired zone definition, to decouple zones from one another and to prevent overheating in any one zone. In this manner, the temperatures within each zone, and thus the temperatures of the printed circuit boards can be carefully controlled.

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Waltham, MA, United States of America

Walter J Hall