Additive manufacturing is a key technology to providing innovative solutions for optimized optical instruments, meeting the growing demand for lightweight optical instrumentation aboard space and unmanned aerial vehicle (UAV) platforms. To prove the feasibility of its ceramic 3DOPTIC service, 3DCeram produced a plane mirror for front-end laser engine (galvo-mirror for high-energy laser application) and optical applications, applying additive manufacturing to the design and manufacturing of the optical substrate.
In general, an optical system needs to satisfy requirements for high stiffness to guarantee the stability of the line of sight, and high strength to withstand the harsh mechanical and thermal environment. It also needs to show high stability to ensure optical performance as a mission component. Traditional manufacturing of optical components, even at the highest technological levels is a lengthy multi-step process that includes labor-intensive (even if the workflow is partly automated) procedures for obtaining a starting block of material, milling, grinding, polishing, coating and integrating within the system.
On the other hand, the use of AM presents a number of clear benefits, including weight reduction through a complex geometry, reduction of lead time and much lower material consumption. In addition, the increased freedom in geometry translates in much greatest and easier system integration.
Eye on the prize
3DCERAM’s process allows the production of “custom made” ceramic optical substrates resulting in decreased risk during the manufacturing process. The process developed by 3DCERAM relies on the ability to directly 3D print the 10% of material that is required to make the part, rather than milling away 90% of the ceramic to create a net-shape mirror.
AM enables optical system designers to explore new mirror geometries, including semi-closed back structures, integrated interfaces, and conformal ribs, opening up new perspectives for the next generation of instruments. These will increasingly include increasingly compact solutions with integrated functions (thermal insulation, cooling channels), a limitation of mechanical & thermal interfaces and integration of the optical function as part of the device’s own structure
By implementing the 3DOPTIC solution, manufacturing steps are dramatically reduced from 6 to 3.5: 3D printing, polishing, and coating. The integration of the interface can be done by simple gluing as the device is designed with system integration in mind from the very start.
Consequently, users decrease the risk of issues occurring during manufacturing, while opening up a new way of developing cooled optical systems, active optical systems or freeform optical surfaces. The net shape capabilities AM also improves the quality of the integration/bonding process with increased accuracy.
The choice of ceramic used for the production of optical parts is also a very important part of the 3D process. Elements to consider are the required mechanical and thermal properties, stiffness and density and the coefficient of thermal expansion (CTE).
3DCERAM’s 3DMix materials for the CERAMAKER line of additive manufacturing systems include a range of pastes (slurries) and suspensions to achieve optimal printing results of optical devices. These pastes have been developed to guarantee a quality equal to traditional methods. 3DCERAM has optimized its paste with the customers’ criteria in many cases as an on-demand formulation of ceramic paste to adhere to the machine’s parameters. This has permitted clients to use their ‘own’ ceramic powders while using the breakthrough technology of ceramic 3D printing.
Commercially available materials used for 3DOPTIC include Alumina (AI2O3), Cordierite and Silicon Nitride. 3DCERAM also provides on-demand services, with a team experts able to take into consideration the specific material needs and requirements of any interested party. In this case the powder supplied by a client is analyzed, tested and benchmarked.
While industrial 3D printing of foundry cores is expected to represent one of the larger revenue opportunities, technical ceramic applications (such as aerospace applications) are expected to experience the fastest growth in the near future. Aerospace applications, which are currently the existing applications of ceramics additive manufacturing, remain the most significant revenue opportunity and are expected to grow to represent up to $289 million in revenues by 2027.