Internship LPBF Slicing and downskin improvement

Functieomschrijving

Development of an advanced Laser Powder Bed Fusion build file generation tool for producing homogeneous and predictable material.

Graduation project or internship.

Background

Additive Manufacturing (AM) technologies build products layer by layer using data directly from 3D CAD models. AM has high potential for improving the performance and reducing the weight of parts, which is especially beneficial for aerospace applications. Reliable and predictable behaviour is essential for safety in aerospace applications.

This internship project focuses on Laser Powder Bed Fusion (L-PBF) technology. With L-PBF, complex products are constructed layer-by-layer within a powder bed. The metal powder is selectively molten by a laser beam. Dedicated software tools are used to generate a build file in which the applied process parameters and the laser scan pattern for each layer are defined.

The complex design can easily cause large temperature variations during LPBF production, which can result in variation of material properties, for example in overhanging structures and sharp corners trapping heat. Currently available software tools do not offer the required flexibility in generating dedicated scan patterns with variation of process parameters to produce homogeneous material with predictable properties.

Assignment

The goal of this project is to develop a software tool for creating toolpaths for the laser and implementing appropriate laser scanning strategies for bulk and overhanging regions. Currently, the creation of laser toolpaths is done using licensed software, limiting the flexibility in customising the toolpath and scan parameters.

Open source python libraries such as the PySLM library can be used to build a software tool that generates the scan vectors and identifies regions where different scanning strategies should be applied. This increases control over the toolpaths and allows for more advanced optimisation of the LPBF process.

Once the basic structure of the software tool is operational, more complex scanning strategies can be implemented to improve material quality and homogeneity in complex geometries. Some examples of these geometries are overhanging regions that either require significant amounts of supporting structures or advanced scanning strategies to prevent large temperature variations and deformations.

As complex geometry can significantly increase the time required for the generation of the toolpaths, it is essential to keep in mind the efficiency of the software tool and possible optimization through rewriting in a lower-level language such as C++.

Activities

• Set up a project plan
• Literature study into LPBF in general
• Slicing of CAD geometries for Additive Manufacturing
• Methods of down-skin identification
• Enable application of dedicated scan strategies in down skin areas
• Enable application of variable process parameters in scan strategy
• Design a test geometry for validation of slicer
• Fabrication and investigation of processed structures
• Analysis of experimental results
• Writing the report

Profile

For this internship, we are looking for a curious, enthusiastic, academic-level thinking and independent student who has affinity with Python and Additive Manufacturing.

What we offer

• A challenging graduation project/internship in a high-tech, result-orientated work environment
• Weekly supervision and availability of the technical staff for support
• An internship allowance
• Working on an actual R&D project as part of our team
• Internship results to be used in current and future projects

About NLR

Royal NLR is a research organisation focused on innovation in transportation, working to make the world of transportation safer, more sustainable, more efficient and more effective. Over 1000 professionals work on research and innovation.

This assignment is hosted by the Metal Additive Manufacturing Technology Centre (MAMTeC) within the Aerospace Vehicles Metal Additive Manufacturing and Computational Mechanics (AVMC) department.