11:15am - 11:30am
RECILS: high resolution and high-speed SLA 3D printer using a plane building platform and a cylindrical glass window
The University of Tokyo, Japan
We propose a novel stereolithography 3D printer configuration, called RECILS, achieved by combining a plane building platform (BP) and a cylindrical glass window (CW). The BP is deployed above the sidewall of the CW placed horizontally with a gap of 10 micrometer to 40 micrometer. UV curable resin is supplied into the gap and cured by the UV laser light passing through the CW. The UV laser light with a spot size of 10 micrometer is scanned lineally along the gap by a polygon mirror. The UV light is modulated by the STL data, and the BP is translated in a direction perpendicular to the laser-scan direction, synchronized exactly with the laser scan. This operation is equivalent to a raster scan. The subsequent layers are formed below the previous layer and accurate 3D-modeling is enabled. Additionally, the use of a CW eliminates peeling process and greatly reduces the manufacturing time.
11:30am - 11:45am
Additive manufacturing & the need to get the laser beam right
MKS Instruments - Ophir Brand, Germany
Is additive manufacturing ready for mass-production? The answer really boils down to reproducibility. When it comes to selective laser melting, the constancy of the laser parameters is of great importance. Both, the manufacturers of the laser systems and the users thereof should be aware of the quality of the focused beam. As measuring a (high power) laser beam in the limited space of a production chamber is a challenge, new measurement technology had to be developed. Today, different technologies are available to measure the focused beam quickly and cost-effectively within the process.
Nicolas Meunier, Business Development Manager High Power und Automotive Products Ophir, introduces key measurement techniques, outlines their impact on the way to mass production and explains how to achieve reproducibility in laser-based additive manufacturing.
11:45am - 12:00pm
Arrangement for the benchmarking of in situ process monitoring of topographical process signatures within the laser powder bed fusion process
1Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, 91052 Erlangen, Germany; 2Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052 Erlangen, Germany
Additive manufacturing technologies such as powder bed fusion of metals by a laser beam (PBF-LB/M) offer great potential for production of geometrically complex components. Yet, physical defect mechanisms lack fundamental understanding. Crucial for broadening process knowledge is in-situ monitoring of observable process signatures related to the powder heating, melting, and solidification processes. Whereas the geometry and temperature profile of the melt pool have been intensively examined, little is known about topographical process signatures occurring in PBF-LB/M. In this paper we (i) identify topographical process signatures within PBF-LB/M, (ii) relate them to physical defect mechanisms and (iii) evaluate monitoring approaches proposed in literature to access them. Based on that, we present an experimental set-up with high spatial and temporal resolution consisting of a high-speed imaging (HSI) camera and a low coherence imaging (LCI) system. The coaxial arrangement enables simultaneous observation of the melt pool behavior and topographical process features within PBF‑LB/M.
12:00pm - 12:15pm
Spatially resolved melt pool monitoring for process characterization in laser powder bed fusion (LPBF)
BIAS - Bremer Institut für angewandte Strahltechnik GmbH, Germany
Laser powder bed fusion (LPBF) is a frequently used manufacturing process for complex shaped geometries, e.g. bionic structures. The part quality often depends not only on process parameters but also on geometrically induced changes in thermal conditions. Thus, already identified parameters may need to be adjusted to the geometry. Here, a temperature measurement provides information about the current process state due to its recognition of heat input, accumulation and flux during build-up and thus assists the parameter development.
The present work applies a spatially resolved temperature measurement for process monitoring in LPBF using 2-channel-pyrometry. A lateral resolution of 10 µm is achieved within the complete build-up volume of 250x250x250 mm³ by the coaxial integration of the pyrometric camera system into the beam path of a LPBF machine. The melt pool area was identified as a suitable indicator which enables the prediction of part density during build-up process.
12:15pm - 12:30pm
The final steps towards guaranteed quality and first-time-right - 3D printing with powder and wire enabled by OCT sensor technology
1Precitec GmbH & Co. KG, Germany; 2Institut für Strahlwerkzeuge (IFSW), University of Stuttgart, Germany
Today’s manufacturing processes, especially 3D printing with powder or wire, presuppose Industry 4.0 solutions, which require supervision of every single production step. Transforming machine elements into intelligent cyber physical systems involves the integration of smart sensors for condition and process monitoring. As photonic solutions are by nature contact free processes it would be advantageous if the sensor is based on light as well, if the light could be coupled into the beam path of the processing laser and if the sensor can really measure surface topography in micrometer resolution. In this case the production process can be directly connected to the CAD data set, the process could be controlled to eliminate geometrical deviations to the desired geometry and first-time-right is not a pious hope anymore. We talk about controlled individualized lot size 1 production based on OCT sensor technology.