Finished Internal projects

Internal projects are initiated, controlled and carried out in very close cooperation with the industrial partners of the DMRC. The industrial partners of the DMRC finance the internal projects and benefit significantly from the results. Industrial companies benefited in particular from special support from the state of North Rhine-Westphalia.

The project deals with the recycling optimized material PA 2221, especially its ageing behavior and resulting powder and part properties. Another focus is on the cooling process of the powder cake, which is currently not known well. Therefore, a temperature measurement system is implemented within a laser sintering system. In addition, the cooling process is simulated as basis for future process optimizations.

Integration of damping functions into existing components via additive manufacturing processes.

To enable the use of AM in broad industrial practice, specific tools are required. Function-oriented active principles are a proven tool in the design process to find solutions. Within the project corresponding active principles are developed, especially for AM, and verified on demonstrators and applications. The potential of a function-orientated AM-design is illustrated and examined on industrial applications. In 2017, the focus was on the topics “heat transfer” and “structural optimization”.

The aim of this project is to establish a database that is necessary for the direct manufacturing of parts via the Fused Deposition Modeling in the toy industry with the material ABS. For this, not only the strength properties and the influencing parameters on the strengths have to be worked out, but a knowledge of possible surface finishing methods is also needed in order to create a component that meets the given requirements. Another very important topic is the dimensional accuracy of the parts. A very high fitting accuracy is necessary in some applications. This research project is divided into three work packages. First the mechanical strengths are analyzed, then the surface characteristics in combination with the dimensional accuracy of FDM components manufactured with the material ABS are investigated experimentally.

The project DynAMiCS aims at developing an adaptive check system in order to check for (1) broad potentials, (2) products and services and (3) business models related to Additive Manufacturing. The goal is enabling the DMRC to convey its competences to the industry in a pragmatic fashion. In the context of this project, the fifth sequel of the study “Thinking Ahead the Future of Additive Manufacturing” is going to be composed.

Goal of the project is a strategy allowing the DMRC to become a leading institution in Additive Manufacturing. A strategy is a guideline for daily operations along the way towards a visionary future. It contains a mission statement, core competencies and strategic positions. Defined measures and consequences will help the DMRC to implement the strategy. In the context of this project, the fourth sequel of the study “Thinking Ahead the Future of Additive Manufacturing” is going to be released.

The project “Dimensional Tolerances for Additive Manufacturing” (DT-AM) has two different aims. The first aim is the systematically determination of dimensional tolerances that can be stated if the processes Laser Sintering, Laser Melting and Fused Deposition Modeling are workshop-commonly used. Secondly, relevant process parameters and manufacturing influences will be optimized in order to reduce dimensional deviations.

Additive manufacturing processes create parts layer by layer without using formative tools. Hence, they have a great potential to provide new design freedoms to their users. To publish these freedoms and to support a suitable design for manufacturing, design rules for additive manufacturing are required. However, profound knowledge about such rules is not completely given at time. Thus, the Direct Manufacturing Design Rules (DMDR) project had the objective to develop design rules for additive manufacturing.

The project Direct Manufacturing Design Rules 2.0 (DMDR2.0) has the aim to extend the range of validity for design rules that have been developed previously. Therefore, it will be investigated if and how far the design rules are applicable for different boundary conditions given by different materials, parameters and machines. The additive manufacturing processes laser sintering, laser melting and fused deposition modeling will be considered.

The application of additive manufactured end-use parts requires detailed information regarding mechanical properties, e.g., static strength properties. In many applications, changing load conditions occur, so components burdened not only static but increasingly dynamic. In this project, dynamical values of LS parts build with PA 12 as well as FDM parts build with Ultem 1010 and Ultem 9085 will be carried out. Additionally, the creep behavior of FDM parts will be analyzed.

The main goal of the project “Fatigue Life Manipulation” is to extend the total life time of components. Using intrinsic advantages of additive manufacturing processes, notched parts will be produced in order to manipulate the fatigue life. It is expected that due to changes in stress distribution caused by the notch forms, notch sizes and notch orientations the crack growth behavior will be influenced.

The aim of this project is to reduce the high residual stresses and the shrinking of the material caused by the high cooling rate during the building process, which leads to crack formation. In this project, a heated building platform helped to reduce the temperature gradient, which leads to certain microstructural changes that made these materials processable with selective laser melting.

Information about the mechanical properties are essential for designers in order to design products for application. Particularly for a dynamical application, like in the automotive industry or aircraft, the fatigue and creep behavior of the parts has to be known, so that the parts fulfill the calculated product life cycle.

A robust Finite Element Analysis (FEA) model for complex loaded cellular light-weight structures will be the aim of the present project. Based on the findings of a preliminary linear elastic simulation the examinations will be extended to linear-plastic deformation behavior including several materials e.g. 316L stainless steel (ductile) and Ti-6Al-4V alloy (brittle). The cellular structures tested will be manufactured by Laser Sintering (LS) in order to verify the developed FEA model.

The availability of high performance LS materials is still limited to mainly polyamide 11 and polyamide 12 powder. However, these materials do not match to requirements of some advanced applications, for example in the electronics or automotive industry where higher material strengths and temperature resistance is required.

Ti6Al4V is the most commonly used alloy, because of its well-balanced property profile. Different heat treatments allow to tune microstructure and properties for different requirements and applications. During the use phase of powder, effects like out-washing of fine fractions, pick up of oxygen as well as enrichment of splashes change powder characteristics.

To quantitatively assess the surface quality of laser sintered parts a reliable characterization method will be developed. This method serves as analyzing tool for the surface quality of laser sintered parts depending on different machine parameters in order to describe the correlation between machine settings and surface quality. Further work will cover post processing methods to improve the surface finish with reasonable effort in terms of costs and labor.

This project examines PrimePart ST, a polyamide-based thermoplastic elastomer (TPE-A). Unlike established laser sintering materials, this new material is very elastic. This project aims at examining various material and part properties to help with its qualification for future application.