By Nick Allen, Managing Director, 3DPRINTUK
3D printed parts are now commonplace in end-use applications, but not all are used in as exacting an environment like the ones used by Planet Ocean, based in Camberley, UK.
Planet Ocean is a specialist in the provision of high-quality, marine scientific instruments for research, survey, naval, and operations support. The company represents some of the world’s foremost manufacturers of oceanographic and marine meteorological equipment covering a wide spectrum of disciplines from radar wave measuring systems, to seabed assessment systems, and autonomous underwater and surface vehicles. ecoSUB Robotics — a company spun out of Planet Ocean to engage in the design and manufacture of underwater vehicles — regularly uses 3DPPRINTUK as a supplier for a number of key 3D printed parts. These 3D printed components have to operate in saltwater, in very low temperatures, and under extreme pressure some 2,500 m below sea level, while at the same time remaining water-tight and intact.
Notes Jeremy Sitbon, Chief Robotics Engineer – Marine Robotics Systems at ecoSUB Robotics, “The parts that we use in our underwater vehicles have to be strong and robust, and absolutely conform to design intent. 3D printing is preferred over injection molding as we find the technology more versatile, and the design freedom allows us to innovate great parts. Also, our volumes are low (maybe 10 parts per month) so injection molding would not be economical. Add in the fact that with 3D printing we can customize designs for individual clients, and the choice is clear. We use 3D printing for prototyping and production applications. For us, it is vital that the prototype and production parts that we order are competitively priced, high quality, and speedily delivered, and in 3DPRINTUK we find all of this and more. Key to the success of our relationship is the inherent knowledge and experience that resides within the 3DPRINTUK team. They have a ‘can do’ attitude, and their understanding of Design for AM (DfAM), and the management of the 3D printing process to maximize efficiencies and therefore reduce costs per part are of vital importance to us.”
All the 3D printed parts used by ecoSUB Robotics for production are trialed in small prototype batches and integrated into the marine vehicles before production quantities are ordered. The reason that cost is important to the company’s design team is that they see enormous potential for their underwater vehicles not just to be used by professionals within the military and oil and gas sectors, but also research scientists gathering important information about climate change. Price is key to making this advanced technology available to a wide user group. ecoSUB Robotics takes advantage of both the MultiJet Fusion (MJF) and Selective Laser Sintering (SLS) services offered by 3DPRINTUK to maximize the benefits of the different polymer powder bed fusion (PBF) processes.
Sitbon continues, “We are constantly on the lookout for the most cost-effective 3D printing solution for our underwater vehicles, but we cannot compromise on quality at all. There are two different kinds of parts and components in the vehicles, external parts that can be seen, and internal parts that cannot. The external parts need to be yellow for the sake of visibility, and we use SLS for these as the technology produces whiter parts than MJF, and in our opinion, this makes the addition of a color that much more definite and striking. MJF parts are somewhat greyer, and this makes the processed color less vivid. For parts used internally, which do not need to be colored and do not need to be aesthetic, we use MJF parts as they are typically less expensive. So, I guess we have the perception that SLS as a process is more versatile when finishing and dyeing are required, but as we are convinced over time that MJF improves in this respect, we will most likely shift all parts to MJF due to price considerations and the fact that more exacting tolerances can be made repeatably with this 3D printing process meaning improved detailing on parts..”
ecoSUB Robotics sees pros and cons with both SLS and MJF, but finds that MJF parts seem to have a better finish before post-processing, and this would be an advantage for external colored parts which when made via SLS tend to get dirty and look worn over time and under heavy usage.
Sitbon concludes, “The assessment of SLS and MJF will continue, and we are happy to be guided as to which process to use for internal and external applications. Because of the harsh environments that some of our vehicles are used in, the integrity of the material chosen is everything, and we are amazed by both processes, which can withstand intense cold, high pressure, and the corrosive nature of saltwater, and still pass rigorous water-tightness tests.”