For the measurement of the air-suspended particle mass concentration and sampling of particles for offline‑analysis, aerosol samplers like impactors, or cyclones are common tools. Usually, these are made from stainless steel by precision machining and some commercial samplers are available. However, for specific use cases, adapted geometries are needed. For that, 3D-printing can be used as a quick and easy way to produce prototypes.

We designed a simple round-nozzle impactor with a cut‑off diameter of 1 µm. The impactor and nozzle plates were printed on a stereolithography 3D-printer (see Figure left). A 1 mm nozzle was achieved with sufficient print quality. The repeatability of the printing procedure and the nozzle diameters were evaluated by microscopy and ImageJ. The printing accuracy between 6 repeated prints was within 5% of the desired nozzle diameter. For testing of the printed impactor, a monodisperse test‑aerosol produced in a Sinclair-La-Mer-type particle generator with particle sizes ranging from 0.2 to 3 µm was used. The particle size distribution was monitored with a PALAS welas 1200. As shown in the right figure above, a 50% cut-off diameter of 1.01, 1.51 and 1.65 µm could be determined experimentally using three repeated prints of the 1 mm impactor nozzle. The large deviation in comparison with the predicted cut‑off might be due to softening of the printing material during the experiments, the deviation of the print from the design parameters and improper sealing of the printed parts. 

Different other devices, such as isokinetic sampling pieces, virtfual impactors and cyclones are also printed and currently be evaluated.