Choosing a suitable fume extraction system
Whether you’re looking for a one- or two- solder tip workstation solution, or a larger system for a production cell, there are a number of key elements to consider. These can help to identify the most suitable choice of manufacturer and model for your application.
For all systems, the highest priority is naturally the effectiveness of the extraction and filtration performance in protecting workers from harm and their employers from non-compliance issues or compensation claims. Features such as high volume extraction, and a wide range of easily-fitted extraction arms, nozzles and accessories to optimise workstation configuration are important. However, each different system also has other considerations of its own. For volume extraction, economy and convenience of set-up and use can be important. Volume extraction systems should be mobile to maximise utility and minimise installation costs.
Maintenance costs are also reduced if the arms and nozzles do not need daily cleaning, and energy costs are saved if the cleaned air is recirculated back into the work area rather than using external air that needs heating or cooling – note however that an exhaust to atmosphere option may be needed for situations where recirculation is not allowed. Using highly reliable, maintenance-free turbines and motors, and generally investing in products with high-quality components also reduces maintenance costs as well as possible downtime. Filter exchange should be as easy as possible too.
Remote control and automation also improves efficiency; cost savings can be made through automatic air flow control which intelligently regulates the airflow at each workstation, regardless of how many workstations are connected. This increases filter lifetime and saves energy. Filter condition monitoring ensures that clogged filters are noted and exchanged before they can excessively degrade the extractor’s operation. An RS232 serial port on the extraction unit provides an opportunity to integrate the extractor’s software with a plantwide management system or other process equipment.
There are other issues that relate to the utility of the systems. If the extraction unit is centralised, what is the maximum bridging distance in metres to the work areas, and how many work stations will it support? If the extraction units are on wheels they can be re-deployed with minimal effort as production requirements change. The acoustic noise generated should be checked if the extraction unit is to be sited near workers.
Multiple hand soldering work stations with tip extraction can be set up. The Weller ZS 20T, for example, is a mobile unit that can drive up to 20 irons. Weller FE (Fume Extraction) soldering irons feature a smoke tube integrated into the handle. The tube is positioned directly above the joint, collects any fumes produced during soldering and connects directly into some Zero-Smog systems. Some of these systems also support a safety rest with Stop + Go function; this switches the extraction system on when the FE soldering iron is removed from the safety rest and off after a short delay when the iron is replaced. Fume extraction attachments can be retro-fitted to non-fume extraction Weller soldering irons.
Additionally, Weller tip extraction units support maximum bridging distances to 200 m, and electronically controlled variable pump speeds adjustable at the unit, by RS232 remote control and for the WFE 20D system, by PC. Vacuum and extraction performance can also be regulated. Tip extraction units can also feature control electronics that ease maintenance and improve performance. Differential pressure across a filter can be checked and revealed with LEDs, and the unit can be switched off automatically if a preset contamination level is exceeded. Filter operational lifetime in hours can be set; the need for filter change can be shown, allowing sufficient time for filter procurement and replacement.
Tip extraction and volume extraction systems differ in terms of vacuum requirements. Tip extraction calls for high quality, constant levels of vacuum across the installation, which is achieved by using pipe systems with a relatively small diameter. Volume extraction systems require a large volume of air to be extracted and the level of vacuum is of lesser importance. This means that a relatively large diameter pipe system is required. If the pipe diameter is too small the flow resistance is increased and extraction capacity reduced.
Conclusions
Soldering activities, whether on a large scale unit such as a wave soldering machine or with a soldering iron at an individual work station, create fumes due mainly to the rosin flux within the solder. These fumes present a health hazard to workers if inhaled, as they can trigger asthma and cause other health problems. Accordingly legislation exists to guide employers and protect workers from this risk.
Companies such as Weller offer comprehensive solutions for all types of soldering applications, including both solder tip and volume extraction. Such organisations can advise on the best configuration for any given situation as well as offering the components needed to fulfil the configuration as specified.
Managing Solder Fume Extraction. Date published: 24th July 2015 by Farnell