UpNano
UpNano GmbH has co-developed a novel manufacturing process for 3D printed fused quartz objects, enabling the production of high-precision shaped parts in the mm and cm-range.
The process is based on Glassomer GmbH's glass production technology and has been modified for two-photon polymerisation (2PP) 3D-printing using UpNano’s NanoOne high-resolution printing system.
Manufacturing minuscule and complex 3D objects in glass is considered a challenging process, especially if the required material is high-quality fused silica (SiO₂) glass, which has a high melting point. Fused silica is said to offer superior optical properties, biocompatibility, high chemical inertness and exceptional heat resistance, making it an ideal material for a vast range of applications. The only useable methods for manufacturing small and complex fused silica parts, however, are said to be based on non-commercially available equipment and include melting glass fibres using laser beams or fused deposition modelling to produce soda lime glass. These methods, according to UpNano, often produce parts with undesirable rough surfaces.
To address this, upNano has worked with Glassomer to develop a rapid 3D printing process capable of producing smooth fused silica parts in the mm and cm range with features in the μm range.
“It’s a three-step process,” explained Markus Lunzer, team lead of Materials & Application at UpNano. “The first step is to design and print the desired structure using all the advantages 2PP 3D-printing offers. The second step is to remove organic binder material followed by a high temperature sintering process, the third step.”
At the core of this new technology is a newly developed nanocomposite “UpQuartz”. In addition to SiO2 nanoparticles, it contains a specially designed polymer matrix that allows the composite to be 2PP 3D-printed. The printing process produces a 'green part' that already has the shape of the final and desired structure with the polymer matrix being removed to obtain the fused silica product in the end. Heating the green part to 600°C then effectively removes the polymer matrix, leaving behind the 'brown part'. The structure is sintered and fused after exposure to 1,300°C before the object undergoes isotropic shrinkage of approximately 30% in the post-processing phase. This can easily be compensated for by an appropriate upscale of the green part using UpNano’s software.
"This innovative production process we developed," added Lunzer, "is ideally suited for larger 3D-printed glass parts that require high-resolution and high-precision, in the fields of engineering, and chemical, medical or research applications."
UpNano believes this new development marks a significant advancement in the potential of 2PP 3D printing, following its recent success in advancing the material testing of 2PP 3D-printed parts using UpNano printers and resins for macroscopic test specimens. In addition, the company’s printers have recently been used to achieve a significant milestone in 2PP 3D-printing by producing holistic embedded microfluidic chips as well as tungsten and platinum microstructures with (sub-)μm resolution.
