Fume extraction system avoids thermal shock in reflow and wave soldering

Fume extraction system avoids thermal shock in reflow and wave soldering

Purex International has incorporated a unique vacuum control capability in its Purex Powerflow fume extraction systems...

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Purex International has incorporated a unique vacuum control capability in its Purex Powerflow fume extraction systems. By automatically keeping air flow constant, accurate temperature profiles can be maintained in reflow ovens and wave soldering machines. The risk of thermal shock is therefore minimised, which improves product quality and reduces reject rates.

Fume extraction system avoids thermal shock in reflow and wave soldering

Using conventional fume extraction systems, the air flow will vary as filters fill up with solder particles through their life and become partially blocked. With the Purex system, Purex International's microprocessor-controlled IPCP (Intelligent Purification Control Program) monitors the vacuum in the system and automatically varies the pump's motor speed to keep a constant vacuum. The air flow rate is therefore kept constant, to within a variance of less than 1% throughout the filter life.

Due to the cooling effect of the extraction air flow, conventional extraction systems require frequent and time-consuming manual adjustments to the heating elements of the reflow oven or wave solder machine. These adjustments, with the resultant potential for operator error, are necessary to maintain the required temperature profile. The Purex system avoids this problem completely, with automatic control taking the place of operator modifications.

With a new, unblocked filter, the IPCP's motor control capability allows the motor to be run at a lower speed. This saves power, leading to lower running costs, and extended motor life. The flexibility of the IPCP also means that the motor can be driven at higher speeds when required, enabling higher pressure extraction to overcome the increased resistance as a filter blocks.

Control panel of a Purex Fume Extractor

The Purex system also solves the problem of fume build-up in the reflow oven caused by extraction speeds dropping. The fume build-up leaves debris on the products, the heating elements and the inside surface of the oven. This debris makes the oven less efficient, and leads to higher product reject rates. It also requires maintenance to remove it, leading to down-time and lost production.

The IPCP allows the Purex extraction system to be easily linked to the reflow oven control system via an industry-standard RS423 interface. The Purex system can then automatically switch off the oven if extraction is insufficient, and the oven can automatically switch on the Purex system at start-up. An optional feature is the Intelligent Purification Network (IPN) which allows remote diagnostics and adjustment of a group of extraction systems from an office PC.

For further information please call Purex International on 00 44 (0)1709 763000.