Improved filtration using additive manufacturing

Burns, Neil and Geekie, Louise and Travis, Darren and Burns, Mark and Weston, David P and Rennie, Allan (2014) Improved filtration using additive manufacturing. In: 9th International Conference on Additive Manufacturing and 3D Printing, 2014-07-08 - 2014-07-09, The Nottingham Belfry.

Abstract

Industrial processes that involve fluid usually have filters which create resistance and require more energy for pumping. Desirable characteristics of an efficient filter include maximising the open area, but this decreases overall strength. Traditionally, metal filters have been manufactured using perforated plate and mesh. We successfully used additive manufacturing (AM) to create filter designs, that cannot be manufactured using conventional methods, These filters were designed around the apertures in the filter. This filter delivers decreased resistance, therefore reduces end-users energy costs and decreases their carbon footprint. 3D filter designs were created to deliver effective filtration by using the AM capabilities to maximise the open area (aperture size) whilst retaining strength in the filter. In effect we combined the filter portion and the support portion of a conventional filter into a single part. During the design process we had to develop new approaches in our CAD techniques to accommodate the high percentage of space compared to the relatively low percentage of material in our lattice design. Low density per unit volume also increased the slicing time for the layers to be defined for uploading to the machine. The integrated AM filter was created with incremental increases in aperture size, and the series of filters printed using the same material files. We then analysed the strands and aperture sizes within the lattice of the integrated filter using the optical techniques of SEM and X-Ray CT. Manipulation of the material files used in subsequent builds led to increased control of the quality and consistency of the lattice strands which in turn has led to increased consistency in the aperture sizes in the filters produced. We have therefore refined the AM process used to manufacture our filters to an effective process. Metal AM was used to develop a wedge wire filter that can be manufactured in a single step process. This eliminates the significant costs and time for conventional tooling requirements as well as reducing the overall lead time to delivery. The AM filter design to reflect wedge wire overcomes conventional fabrication issues. Filtration efficiency will be investigated by comparing the flow rates of a conventional and of an AM wedge wire filter. AM technology has enabled the production of innovative 3D designed filters that have design elements which significantly increase filtration efficiency. Industrial use of these 3D filters may reduce the end users carbon footprint.