Abstract: Volatile organic components are controlled in electronic component assembly processes to prevent deposits on finished circuit boards and the like. The method of controlling the components in a machine having a plurality of enclosed heating zones followed by at least one cooling zone containing gas, and a conveyor for passing circuit boards therethrough on a conveyor path, comprises the steps of removing a portion of gas from at least one of the heating zones, cooling and filtering the portion of gas remote from the heating zones and the cooling zone to condense at least some of the volatile components in the portion of gas, and returning the cooled and filtered portion of gas to at least one other zone of the heating zones and the cooling zone.

Abstract: A gas knife cooling system for reflow soldering cools soldered articles by impinging a gas flow directly on the articles and as a result uses less cooling gas. A heater is associated with the cooling system to remove flux deposits. The cooling system is installed in the cooling section of a reflow soldering apparatus and comprises at least one gas knife to direct a gas stream at soldered products passing through the cooling section on a conveyor. A heater is associated with the gas knife which is activated for predetermined cleaning cycles to heat the gas knife to a temperature above flux vaporization temperature of flux deposits from the soldered products.

Abstract: A multi stage heater heats items on a conveyor so that they follow a predetermined temperature profile. The heater is used for printed circuit boards or the like when heated for soldering and avoids thermal gradients that can occur with heating different materials. The heater has a first heater for applying a first quantity of heat to items on the conveyor, a temperature sensing device for determining temperature of items leaving the first heater, a second heater downstream of the first heater and a control system which compares signals from the temperature sensing device with a predetermined temperataure profile to produce a first control output to control the first heater and a second control output to control the second heater so that items passing through the heater follow the predetermined temperature profile.