The Fraunhofer Laser Technology Research Institute (ILT) in Germany, together with its industrial partners, has developed a new system for the production of high-resolution micro-parts through optical crosslinking. Following the work of the team in the project "High productivity and detail precision of additive manufacturing through combination of UV polymerization and multi-photon polymerization - HoPro-3D", the polymer microstructure can now be produced and customized economically on one machine.
ILT cooperated with LightFab, Bartels Mikrotechnik and Miltenyi Biotec to carry out the "HoPro-3D" project. They have developed a new type of 3D printer, which combines fast two-dimensional exposure - rolling digital light processing (DLP) - with high-resolution laser technology - multi-photon polymerization (MPP), and uses photopolymer to produce micro-parts.
The HoPro-3D 3D printer has two optional exposure systems for high build rate or high accuracy. The DLP module emits light at 365 nm and exposes the basic structure of the micro-parts at 10 micron pixel resolution. As a supplement, femtosecond laser and MPP module can be used to write contour lines with a resolution of about 2 μ m。
The layer-by-layer method makes it possible to build a fine MPP structure on the printed DLP structure, thus creating an extension component with complex structure and high resolution details. The laboratory model built allows the production of components covering an area of 60 x 100 mm2.
Fast and accurate
The control software of the HoPro-3D system enables users to switch between two exposure modules smoothly. In addition, they can use CAD data to decide when to switch during the printing process. In the layer-by-layer stacking process of parts, it is possible to switch between the two processes for many times.
Laboratory equipment used to test the combined process.
Dr. Martin Wehner, head of the biological processing team of ILT, said: "The concept has been put in place, the corresponding machine has been built, and extensive testing has been carried out. After the completion in the spring of 2022, the laboratory prototype has been tested and optimized in an application-oriented way as part of the Fraunhofer SiCellNet network.
The SiCellNet cluster constitutes the central point of contact for the research of new tools and manufacturing technologies for the analysis, sorting and supply of living cells. Therefore, the performance and process control of the combined plant can be optimized.
In the follow-up project "Accurate assembly through high-resolution seamless 3D printing - PANDA" funded by the SME Innovation Program, the ILT team has been expanding the performance based on DLP process since January 2022. The knowledge gained there will be applied to the HoPro-3D system to continuously improve the economic benefits of 3D printing process.
ILT said that there are many potential applications of this technology: microfluidic chips for laboratory diagnosis and rapid testing, micro-mechanical components and complete microfluidic systems for efficient medical point diagnosis can be used for on-site diagnosis around patients without further laboratory testing.
Optical security technology reduces warehouse transportation accidents
There is always a lot of traffic in the warehouse, such as trucks or forklifts passing through the corridor. In this case, especially when people are still working in the workshop, the risk of accidents is high. The optical sensors on these vehicles can provide better protection for warehouse staff and avoid collision.
Dangerous area: In the warehouse, vehicles often cause accidents.
The joint project of BASF, Kinotex Sensor and Fraunhofer Optical Metrology and Surface Technology Application Center (AZOM) has developed prototypes to improve the safety of workers in daily warehouse activities.
AZOM, located in Zwikau, Germany, is a branch laboratory of the Fraunhofer Institute of Materials and Beam Technology (IWS). AZOM's specially designed optical sensors are designed to reduce transport accidents involving industrial trucks. To this end, the partner BASF provided two pallet trucks.
Dr. Christian Fischmann, who is responsible for BASF vehicle engineering in Ludwigshafen, commented: "Every day, hundreds of industrial trucks are driving around our factories and warehouses. In cooperation with AZOM, we are eager to integrate safety technology into our vehicles to provide better protection for our employees."
"Our system is designed to protect users from mechanical extrusion, especially in the area around their feet." Professor Peter Hartman, director of Fraunhofer AZOM, said: "To achieve this goal, our research team developed a special proximity sensor, which can detect when the operator is too close to the dangerous area in front of the vehicle, and then apply the brake."
The laser pulse is emitted with a defined length and the distance between them, and then reflected from the obstacle. This process will generate information about how far away the object is. The real innovation of this system is that it can combine information from multiple directions in space and continuously monitor the sector area around the pallet truck, which is provided by BASF.
The signal from the second optical sensor that responds to the pressure is processed using the distance information from the object - thanks to the cooperation with Kinotex. The tactile sensor can stop the vehicle and automatically move it back slightly to prevent the operator from being crushed.
BASF has shown these two prototypes at professional conferences and trade fairs - users and manufacturers have shown strong interest. "This technology can be used for almost any transport vehicle, but it is a particularly interesting prospect for self-driving vehicles," said Dr. Christopher Taudt, manager of AZOM Surface Measurement Group.
"At present, we are studying the idea of integrating sensors into a modifiable sensor belt, rather than making them a fixed part of the vehicle. This will enable them to be added to any type of vehicle of all manufacturers," he said.
