No abstract

No abstract

In this paper we are exploring the possibilities of 3D printing in the fabrication of mirrors for astronomy. Taking the advantages of 3D printing to solve the existing problems caused by traditional manufacturing, two proof-ofconcept mirror fabrication strategies are investigated in this paper. The first concept is a deformable mirror with embedded actuator supports system to minimise errors caused by the bonding interfaces during mirror assembly. The second concept is the adaption of the Stress Mirror Polishing (SMP) technique to a variety of mirror shapes by implemented a printed thickness distribution on the back side of the mirror. Design investigations and prototypes plans are presented for both studies.

No abstract

Additive Manufacturing (AM) has several potential advantages for astronomical instrumentation: particularly the ability to create custom parts with optimised geometries that cannot be produced with traditional manufacturing. The goal of the EU H2020 funded OPTICON (Optical Infrared Coordination Network for Astronomy; grant agreement 730890) A2IM (Additive Astronomy Integrated-component Manufacturing; PI H. Schnetler) project completed in June 2021, was to develop prototypes demonstrating these benefits. This paper presents the design and additive manufacture of a piezoelectric stack actuator driven, monolithic flexure for the active array of the Freeform Active Mirror Experiment (FAME). Flexure geometry had previously proved difficult to repeatedly produce and AM was considered as a potential solution. Two AM processes were used: powder bed fusion where metal powder is bonded using a laser, and binder jetting where powder is bonded using a polymer adhesive. A topology optimised, flexure hinged frame was designed based on the minimum feature size of each AM machine. This geometry was produced in Aluminium (AlSi10Mg), Titanium (Ti64Al4V) and Stainless Steel 316L. Porosity is a known issue with AM and Hot Isostatic Pressing (HIP): a post process whereby parts are subject to increased temperature and pressure was identified as a way of reducing this, thereby increasing the predictability of flexure behaviour and suitability for vacuum applications. Conformity of AM parts to their original geometry was assessed using external dimensional metrology. X-ray Computed Tomography (XCT) was used to identify internal porosity.