Selective laser etching (SLE) - GMP SA

3D Nozzle

A technique called selective laser etching (SLE) makes it possible to produce 3D structures out of glass. Micronozzles are just one possible use for this technology. The great accuracy and potential for complex geometries that an SLE-made nozzle can achieve, which cannot be done with other technologies, are what make it special. The nozzle size can reach a few centimeters while the smallest channel may have a diameter of only a few micrometers. The nozzle could be used to deliver high-pressure gases and liquids to variable diameter outputs. Fluid dispensing and various printing techniques are examples of potential nozzle usage.

Geneva Gear

The Geneva gear is an arbitrary-shaped micromechanical component and is one of the most used devices for producing intermittent rotary motion. The Geneva mechanism contains two intermeshing elements. By rotating one gear through 360°, another gear is moved by fixed 90° increments. Using SLE technology, these mechanisms can be fabricated out of a single piece of glass without the need for an assembly step. Being assembly-free, the structure can be produced on a small scale (down to hundreds of µm) without extremely complex micromanipulation. Moreover, by attaching a small magnet to the mechanism and placing it over a rotating magnet, we show that smooth continuous movement of the structure can be implemented. This is made possible by the exceptionally fine gaps between the different moving parts of the structure (less than 10 µm) and particularly good surface roughness (~ 200 nm RMS), which allows for minimizing excessive friction.

Threads for Screw

Selective laser etching (SLE) is a femtosecond laser-based technology that enables 3D printing of complex glass microparts in two technological steps: direct laser writing inside the volume of glass and subsequent etching. The SLE technology permits straightforward conversion of the desired CAD design to a 3D micropart. Even mm-size structures with a few micrometers of precision can be printed in this way. One example is threads for screws in glass. Sub-mm size thread structure is hard to fabricate in glass due to its spiral shape and the need for high precision and low surface roughness. These requirements must be met for the screw to be inserted inside the structure without damaging the thread.

Telsa Valve

One of the most promising applications for SLE is microfluidics. SLE-made surfaces can have relatively low surface roughness (~200 nm RMS). SLE technology far exceeds ablation in terms of flexibility and enables the production of 3D free-form structures, such as channels with integrated functional elements, or 3D channel systems embedded inside the volume of glass, bringing new capabilities and flexibility to the field. These properties make it possible to avoid other supplementary processes such as sealing ablated channels or the need to use other manufacturing techniques for integrating some more trivial structures. In this way, Tesla valve microfluidic channels can be fabricated inside the volume of glass. This microchannel design allows the liquid to flow in only one direction.

3D Glass Structures

Selective laser etching (SLE) technology enables the fabrication of true 3D glass structures with complex architecture, for instance, fullerene molecule‑like structures. By using the SLE technique, high selectivity and low surface roughness can be achieved, both of which create the possibility of complex architecture high-aspect ratio structure production. With this technology, the surface roughness of the etched surfaces is typically around 200 nm (RMS). A fullerene molecule-like structure demonstration proves that SLE is suitable for fabricating high-aspect ratio porous complex structures.

Micro Channels Formation

Selective laser etching (SLE) technology permits the microfabrication of complex-shaped microfluidic channels out of fused silica glass. The process consists of two technological steps. First, the desired part of the CAD design is directly written into the volume of the glass, which is subsequently etched away in the second processing step. The SLE technique makes it possible to produce taper-free micron precision channels with a low surface roughness of ~200 nm RMS. Because fused silica glass is transparent in the visible range, biocompatible and inert to most chemicals, SLE‑made microfluidics perfectly suit many science applications such as biochemical research.