There are a series of initiatives worldwide that outline targets for electronic equipment re-use and recycling. Legislation potentially affecting the solder and electronic assembly industries is now being proposed by the European Commission via the Waste Electrical and Electronic Equipment (WEEE) directive and by Japan with the Ministry of Trade and Industry (MITI) outlining targets for electronic equipment re-use and recycling. This proposed legislation will impact not only solder alloy issues but also issues concerning component finishes, component temperature ratings, board finishes, and flame retardancy. Additionally, the EPA is mandating more public reporting by industry on lead emissions. The EPA has lowered the threshold for reporting on lead under its Toxic Release Inventory because lead remains in the environment for long periods of time and is toxic to humans. Previously, manufacturing facilities were not required to report their lead usage. Under current regulations, the reporting threshold is 100 pounds of lead per facility per year and a substantial increase in the amount of information made available to the public.

In order to reduce lead waste, the EMPF utilizes the EVS International/Sono-Tek Solder Recovery System (Figure 6-1). This system processes dross into usable solder that is as free from impurities as the initial solder used. The solder recovery process is initiated by raising the temperature of the solder dross to 310°C and then applying external pressure of approximately 80 PSI while maintaining constant pressure and heat. The spirally-wound heater bands create a small magnetic field of energy. This encourages the iron oxide in the dross to adhere to a matrix, while allowing the molten solder to flow into the ingot tray.

The model EVS 3000 can handle up to 20 pounds of dross per 6-minute cycle, while the model EVS 4000 can process up to 40 pounds of dross per 10-minute cycle. This size is adequate for the de-drossing of even the largest wave-soldering machine in one operation. With recovery rates averaging 75% of the dross by weight being converted to usable solder, the potential cost savings with the EVS systems are significant in addition to realizing environmental and waste handling benefits.

The EVS System provides a closed environment (when used with its ancillary equipment and options) for the recovery of solder from the solder dross produced during the wave soldering process. The EVS 3000 system includes a mobile support cart, dross delivery system, and a stand-alone filter, which consists of a four-stage filter and a high-speed centrifugal fan. The system is designed to be a stand-alone unit, which can operate at the convenience of the user without the need for external extraction.

The solder recovery systems are optimized for use with hot solder dross. The patented process uses pneumatic pressure to extract the solder from the dross at temperature. The solder collected from the process may be stored or returned immediately to the solder bath. This process enables the majority of retained solder in the dross to be extracted. The spent dross is deposited from the operating chamber in the dross bucket via the dross chute. No operator involvement is required other than pressing the start button.
The EVS System saves money by reducing the amount of solder that needs to be purchased and by decreasing the amount of dross that needs to be disposed, making solder recovery a crucial part of all circuit board production. SRS machines of all types will be able to process lead free solder without modification.

This system helps the EMPF comply with local and EPA safety regulations on the safe disposal of lead. If you would like a demonstration of the EVS International/Sono-Tek Solder recovery system, please contact Jeff Stong at 610-362-1200 x224 or jstong@aciusa.org.