Project examples - Quality

Numerical simulation of powder spreading in powder-bed systems

© Photo Fraunhofer IWM

Final surface roughness and porosity is influenced by the homogeneity of the individual powder-bed layers.

Discrete-element-simulations enable in-depth analyses the powder spreading process.

Influencing values like powder properties and processing parameters on part properties can be investigated.

Numerical simulations can replace cumbersome experimental test series to determine optimal processing parameters.

Simulations are performed using the comprehensive software package SimPARTIX.

Link: 

www.simpartix.de

Contact: 

Dr. Claas Bierwisch, claas.bierwisch@iwm.fraunhofer.de, +49 761 5142 347

Optimization of shape distortions during additive manufacturing of graded and multi-material parts

© Photo Fraunhofer IWM

Graded or multi-material parts made out of ceramic and/or metal exhibit inhomogeneous shrinkage during final sintering

Depending on material and part geometry this results in an unwanted distortion and leads to deviations from the desired final part shape

By using detailed sinter models the necessary geometric adjustments can be predicted in advance and thus compensated in the AM building process

The printed green part will then shrink exactly to the desired target shape

By numerical simulation extensive experimental test series to determine the optimal printing geometry and process parameters will be avoided

In the calculations self-developed material routines are used in combination with commercial finite element programs

Contact: 

Dr. Torsten Kraft, torsten.kraft@iwm.fraunhofer.de, +49 761 5142 248

Quality control of powder

© Photo Fraunhofer IFAM

Materials: Ti and Al alloys

Development of powder specifications for Laser Beam Melting

Development of a quality control strategy for ABM powders

Examination of applicability of new in-line powder testing methods
(i.e.: Revolution Powder Analyser)

Project:

ALM2Air (BMWi LuFo V.2, 20W1501F)

Publication:

Zibelius, Daniela: Vergleich von Analyseansätzen zur Bestimmung der Fließeigenschaften metallischer Pulver für die additive Fertigung von Medizinprodukten. Masterarbeit, Fachbereich 1, Studiengang Medizintechnik, Hochschule Bremerhaven (FH), 2016

Uhlirsch, Markus: Charakterisierung von Aluminium-Legierungspulver für Pulverbett-basierte Additive Manufacturing Prozesse. Bachelorarbeit, Studiengang Oberflächen- und Werkstofftechnik, Hochschule Aalen, 2016

Contact:

Claus Aumund-Kopp, claus.aumund-kopp@ifam.fraunhofer.de

Local properties of additive manufactured parts

© Photo Fraunhofer IWM

In the completed EU-project »SIMCHAIN« a simulation chain was developed that allows to study the influence of process parameter on the local mechanical properties of additive manufactured parts.

The material strength and stiffness are calculated based on the local microstructure

In the project the simulation chain was applied to the SEBM-process (Selective Electron Beam Melting )

Project: 

»SIMCHAIN« (Clean Sky Joint Undertaken, Grant No. 326020)

Contact: 

Dr. Dirk Helm, dirk.helm@iwm.fraunhofer.de, +49 761 5142 158

SafetyAM - work safety in additive manufacturing

© Photo Fraunhofer IGCV

In the case of laser beam melting, metallic components from powder material are generated by layered construction and a selective powder melting by means of a laser. Due to the processing of metallic powder materials, however, there are also hazards in the production environment, which are to be classified with regard to compliance with applicable regulations in the area of ​​occupational health and safety.

The application of additive manufacturing processes creates new challenges in the process of factory planning to the companies. These requirements result from the required process components and the materials used for the individual production processes. From the resultant instructions for work safety, practical guidelines have been derived for factory planning regarding handling, storage, constructional conditions and processing of the materials.

Project:

SafetyAM

Publication:

VDI guideline in progress

Contact:

Dr.-Ing. Georg Schlick, georg.schlick@igcv.fraunhofer.de, +49 821 90678-179

Simulation of residual stresses and warpage in stereolithography

© Photo Fraunhofer IWM

Resins for stereolithography shrink during polymerization. During the layer wise curing this leads to residual stresses and warpage.

The amount of residual stress depends on a complex interplay of shrinking, increasing stiffness, decreasing flowability and the shape of the component during polymerization.

The mechanical properties of curing resins can be analyzed at the Fraunhofer IWM experimentally. The results can be conveyed into a material model that help to predict the residual stresses and the warpage.

As the model takes the kinetics into account different types of resins as well as different process parameters can be assessed and optimized.

Projects: 

SimGen (FhG)

Publication: 

C. Koplin, M. Gurr, R. Kübler, R. Mülhaupt, R. Jaeger, Formgenauigkeit in der Stereolithographie, Konstruktion, (2009), 11/12,  p. IW11-IW12

Contact:  

Dr. Raimund Jaeger, raimund.jaeger@iwm.fraunhofer.de, +49 761 5142 284

Strain rate dependent material behavior for dynamic loads in car crash

Additively manufactured materials are analyzed in experiment and simulation. In particular, the strain rate dependence of the material behavior is investigated which is of high relevance for special load cases like car crash.

© Photo Fraunhofer EMI

The material and component behavior of additively manufactured materials is investigated. In particular, the strain rate dependent behavior is analyzed in dynamic experiments and simulations.

The objective is the development of material charts and simulation models able to forecast material behavior, as well as an enhanced understanding of correlations of process parameters and post-treatment of materials.

Dynamic experiments at testing machines and impact tests at accelerator facilities are conducted.

Dynamic experiments with bionically optimized components are conducted at a component crash system.

A scientific material analysis by means of microscopic investigations of metallographic specimens; CT and SEM investigations in the material laboratory support the modeling.

§An evaluation concept expected to allow reliable statements concerning the behavior of additively manufactured components in service is developed.

The results shall be used for the development of application-specific design rules.

Contact:

Prof. Werner Riedel, werner.riedel@emi.fraunhofer.de, +49 761 2714 515