As long as the electronics industry is soldering in manual or automated production processes, it will also need spot extraction systems to extract the fumes produced. This serves to protect both people and products and thus contributes to production efficiency. But it is not only during soldering that harmful fumes are generated. The increasingly frequently used adhesive technology also "produces" substances that should be quickly removed at the point of origin and then cleaned. In this context, the list of "air-polluting" production techniques can be extended almost indefinitely today. One example is 3D printing technology. While not new, it has been used more and more widely in industry in recent years. As new materials become available, the challenge of cleaning and preventing production air from becoming contaminated with pollutants in gaseous or solid form has increased.
In principle, the most effective solution is to collect the vapors and pollutants at the point of origin. The air is extracted, fed to the filter unit, cleaned and discharged into the working room. So much for the theory. In practice, it leads to the question: "How do you find the optimal extraction and filtering system for the respective task? There is a lot of good literature on this subject. In this context, we would like to refer to DGUV 209-200 - a publication of the German Social Accident Insurance with the title: Extraction systems - conception, planning, realization and operation. Alternatively, you can seek the advice of experts, because each area of application has different requirements for the effective suction of production air. One aspect, for example, is the required extraction capacity. For the extraction of soldering fumes at manual workstations, for example, you need an air speed of approx. 8 m/s in the intake pipe. Here a suction arm with 50 mm diameter is suitable. The most effective performance is achieved with an air volume of 50 to 75 m³/h and a pressure drop of 180 to 300 Pa. For soldering machines, the manufacturers specify the required air capacity, e.g. for a reflow oven 1000 m³/h. In addition, the quantity of materials to be processed and the duration of use must also be taken into account.
"In order to consider all relevant aspects when specifying an extraction system, our demand determination concept has proven itself in practice". If the points listed here are clarified, the selection of the optimal filter plant is usually fast settled."
For example, the filter system for soldering systems shown in Fig. 1 includes a pre-filter, a hepa filter in filter class H13 (separation efficiency 99.95%) or H14 (separation efficiency 99.995%) for the visible dust particles. An activated carbon filter is used as the final stage to remove the vapors. The cleaned air then flows back into the working chamber.
A challenge today is to adapt to the control technology requirements in modern production facilities. The goals here are to meet increasing quality requirements and the increasing effectiveness of the systems. This leads to new developments, such as the Airflow switch AFS (Fig. 2), for which a patent is pending, which regulates the air flow by actuating a throttle valve already in the extraction arm, thus further improving the performance of an extraction system.
Lead picture: Klepp Absauganlagen GmbH/Adobe Stock_ tilialucida
11 December 2020
- Occupational safety