The University of Sheffield spin-out FaraPack Polymers ‘FACTUM’ project aims to bring Additive Manufacturing up-to-speed with injection moulding with a revolutionary new process involving infrared light and inkjet technology that has been christened High-Speed Sintering or HSS.
HSS has been Professor Neil Hopkinson’s baby for some time and has the like of Unilever with a vested interest. The latest development takes a significant step forward in making HSS a more sustainable, affordable and feasible technology that could replace many manufacturing process particular in the FMCG industry.
Until now the HSS process has worked by laying down a full layer of the Carbon Black ink and building up from there but what recent studies have found is that by using less ink parts can have greater tensile properties.
By printing in full black ink the team discovered that this was actually in excess of the traditional tensile properties needed for Nylon 12. However, by laying down dots of black ink in each cross-section the team have found they can alter strengths and density of parts at differing levels.
This “greyscaling” of a part means that each part can have differing properties using one material. A part can be stiff on the outside and light on the inside, which, according to Hopkinson, could have significant use in the aerospace and automotive industries.
Gradients in sintering has been explored previously by netfabb whose CEO Alexander Oster explored the idea of using nature’s structures in the design process before printing could give different hardnesses to single prints in relevant areas. This was demonstrated with the SLS printed chair, which was printed as one and features hard legs and a spongy seat.
This HSS process however, could save both time and money, by printing multi-feel parts in one material not only will this be more cost-effective but recycling will be a lot easier. Pr Hopkinson says that this dithering process will be improved in upcoming versions to use true greyscale.