Research and development of additive manufactured bladed disks

Abstract

The contemporary manufacturing methods for bladed disks, also known as \blisks", cause a great deal of material waste. To reduce the material waste and increase the freedom of design, GKN Aerospace requested this project to evaluate additive manufacturing (AM) as a manufacturing method for blisks. Additive manufacturing methods were researched and evaluated based on mechanical properties, freedom of design, material use, and production times. Finite Element Analyses with respective rotation and pressures have been performed and reviewed. All researched methods have been found to have the ability to fulfill the requirements by GKN Aerospace: Power Bed Fusion (PBF) methods and Direct Energy Deposition (DED) methods. This bachelor thesis is a collaboration between GKN Aerospace and students from Chalmers University of Technology and Pennsylvania State University. GKN Aerospace provided the project with CAD models on the current blisk design as well as data about loads and temperatures for the simulations. They also provided a list of parameters for the design including restrictive safety standards and production times. GKN Aerospace stated that Titanium-64 (TiAl6V4) is the preferred metal alloy for production. A large part of the project was to examine and study different methods of additive manufacturing in consideration for the production of blisks. The best method was identified and specified to fit the needs of GKN Aerospace. The team had access to a running Gantt Chart scheduling tool to remain on task and ensure that all parameters of the project were met throughout the semester long project. The team also stayed within the outlined budget, only spending $260.56 on travel and prototyping expenses. The main problem with contemporary additive manufacturing machines utilizing PBF are their relatively small size which led to researching joining techniques. For the DED methods researched, the main problem faced were geometric restrictions in printing complex structures. After reviewing the objectives and comparing them using a Pugh matrix, it was determined what concept would work best for GKN Aerospace. Electron Beam Melting (EBM), a PFB method, should first be used to print the blisk in sections. Then, the pieces should be joined together using Electron Beam Welding (EBW). After this the blisk should be heat treated using HIP and finally machined to reach desirable surface textures. Further evaluation of the mechanical properties of EBM TiAl6V4 and EBW will need to be done by GKN Aerospace to ensure this design will work for this particular aerospace application should they choose to move forward with this concept. Keywords: Additive Manufacturing, TiAl6V4, bladed disk, blisk, EBM, EBW