Department of Mechanical and Aerospace Engineering - PG Seminar - The importance of the processing history on the quality of plastic parts printed using Fused Filament Fabrication (FFF)
In fused filament fabrication with plastics, components are produced by depositing a continuously extruded molten strand along pre-planned paths. The component is therefore not subjected to the same process conditions in its overall volume, particularly during cooling, or crystallization or solidification. Rather, the local deformation and solidification processes during strand deposition, comparable to welding, lead to local gradients in the morphology and ultimately to an anisotropy of the properties. Consequently, the properties of the component transverse to the strand deposition direction are ultimately determined by the quality of the weld between the strands (and layers), which is usually a flaw. For this reason, the so-called z-strength, i.e. the strength between the layers, i.e. perpendicular to the strand deposition direction, is of particular interest for describing component quality in industrial applications.
The presentation will show how the weld seam quality between the strands and layers and thus the anisotropy can be characterized and controlled by intelligent process control. The basis for this is the modeling, in particular of the thermal process behavior, and a derived intelligent printing path specification by a slicer, in which not only the printing time but also the mechanical property profile is implemented as a target variable. Conversely, process control, especially in the case of filled plastics, enables the targeted setting of direction-dependent properties and thus the targeted, material- and energy-efficient use of materials following nature's example.
Professor Alois K. Schlarb currently serves as Senior Research Professor at the Rheinland- Pfälzische Technische Universität (RPTU), is a member of the State Research Center OPTIMAS at RPTU and a visiting professor at Qingdao University of Science and Technology (QUST), PR China. He studied mechanical engineering at the University of Kaiserslautern, specializing in production engineering and company organization.
After his graduation in 1984 he relocated to the University of Kassel, working as scientific assistant to Prof. Dr.-Ing. Dr. e.h. Ehrenstein. He was awarded a doctorate in 1989 for his thesis on polymer processing. From 1988 until 1989 he was also head engineer at the university’s Institut fuer Werkstofftechnik. In the following 13 years Professor Schlarb held different positions in the industry, e.g. the polymer laboratory of BASF SE as material scientist and project manager researching composites, last as Vice President and head of marketing, research and development with B. Braun Medical AG, Emmenbrücke, Switzerland. In November 2002 Alois Schlarb was appointed to a full professorship for "Composite Materials" at the Technische Universität Kaiserslautern (now RPTU Kaiserslautern-Landau) and held this position until March 31, 2022. From 2002 to 2008 he served in parallel as Chief Executive Officer of the Institut für Verbundwerkstoffe GmbH. Since 2018 Professor Schlarb also holds a visiting professorship at Qingdao University of Science and Technology, Qingdao, PR China.
Professor Schlarb served as Spokesman of the Scientific Alliance of Polymer Technology (WAK) from 2009 - 2015 and as President of the Society for the Advancement of Materials and Processing Engineering SAMPE Deutschland e.V. from 2003 - 2015.
He is on the editorial board or scientific advisory board of several journals and has more than 100 publications in peer-reviewed journals. He is also the editor/author/co-author of several books and book chapters.
The focus of his research activities is on process-structure-property-relations and tribology of polymer based hybrid materials.