Characterization and Design of Additively Manufactured Components for Predictability and Materials Integrity - PEI-001

Preferred Disciplines: Engineering Master’s
Project length: 8 months
Desired start date: As soon as possible. 
Location: Charlottetown, PEI
No. of Positions: 1
Preferences: This collaborative project with MDS Coatings Technologies is seeking to recruit a Master’s Student to join Dr. Hsaio’s research lab  in the Department of Sustainable Design Engineering at the University of PEI.
Company: MDS Coatings Technologies

About Company:

MDS Coating Technologies Corporation (MCT) designs and produces metallic-ceramic protective coatings for aerospace and industrial components, including erosion and corrosion resistant coatings for gas turbine compressor parts. MCT has delivered millions of coated airfoils to their customers who are enjoying cost effective, successful and safe operations.

 

Project Description:

Rapid prototyping, or 3D printing, has inspired the imagination of the general public, from simple build-it-yourself “hobby” machines using polymer-based binder material with inkjet functionality, to portable printers that can fashion components in zero gravity on the International Space Station.   The functionality is user-friendly, in that printed material is dropped onto a substrate in viscous plastic form, which solidifies to take on the designed shape.  The resulting piece is a plastic prototype that may be used as-is, for some applications, or as scaled models to assist the product development process.  This work focuses on 3D metal printing, specifically, direct metal laser sintering (DMLS), to build three-dimensional, complex parts using metallic powders.  We integrate materials science, design of experiments, and engineering design for the purpose of manufacturing components with complex geometries and lightweight, high-strength metallic-alloy properties for aircraft applications.  By investigating how process parameters affect the properties of materials, we expect to reduce run-to-run variations in the DMLS process, reduce production and post-production time and costs, and contribute to innovation in using an additive approach to the engineering design of complex components. 

Background and required skills

Research Objectives/Sub-Objectives:

The Master of Science in Sustainable Design Engineering student (MSc-SDE) will work to address the specific objective of optimizing process parameters on the EOS M290 (at MCT) and EOSM100 (at UPEI SSDE) to reduce run-to-run variation, as validated by materials characterization and Design of Experiments analysis.  The MSc-SDE student will participate in the initial commissioning, setup and testing of both DMLS machines, integrating research and design on the EOS M100 with production and testing on the EOS M290.  Specific objectives include:

  • Improved surface finish
  • Reduction of residual stresses from the DMLS process
  • Understanding of component distortion due to residual stresses
  • Understanding of load bearing capacity or deflection limits on thin sections ≤600°C.

Methodology:

Components will be designed using CAD and directly built on the DMLS machines.  In consultation with MCT, the dimensional specifications and mechanical/materials requirements of the desired components will be identified, and using DoE, the effect and interaction between experimental factors will be analyzed and associated with an appropriate range in which to evaluate the dimensional accuracy and performance of the resulting components.  The main process parameters of the EOSM290 and EOSM100 equipment are:  laser power (W), energy density (J/mm2), and source, beam wavelength, beam spot size (mm), scanning exposure area (mm), scan speed (mm/s), z-axis stroke (mm), scan line spacing (mm), temperature (K), layer thickness (mm), all of which are control factors that can impact the resulting material properties of the components.  The materials properties of interest in the DMLS process are: heat capacity (J/kg-K), latent heat of fusion (J/kg), densification coefficient and sintering rate [14], particle size (m) and distribution, density (%), porosity (%), and surface roughness (RA average of surface hills and valleys), stiffness (E, Young’s Modulus), strength (MPa), fatigue (S-N, number of cycles), and hardness.

For the understanding of residual stresses, DoE and finite element analysis will be used to model, simulate, and understand the conditions, geometric features and locations on the build platform that create residual stresses.  The heat treatment, as controlled by various process parameters, of the DMLS process will be optimized to minimize thermal stresses that may form due to non-uniform cooling and incongruent phase transformations that lead to warping, microcracks, and post-processing defects.  Post-processing steps will be evaluated closely, and experimental determination of mechanical properties of as-built components, and components after exposure to controlled annealing temperatures and times will be compared.  Post-processing has the potential to decrease porosity, remove residual stresses, and homogenize the microstructure through recrystallization and grain growth [7], however, it lengthens the production time and costs of the DMLS process.

Surface finish experiments will include optimizing the build speed and resolution at near surface regions.  Surface finish will be characterized by SEM, atomic force microscopy (AFM), and mechanical profilometry.  Mechanical property testing for stiffness, yield strength, and elastic modulus will be conducted on a custom-built, electrically-driven load frame for small samples at UPEI SSDE.  Thin sections exposed to high temperatures will be tested for three-point bending measurements of strain and strain to determine load bearing capacity and deflection limits.

The methodology is focused on optimizing the process parameters that deliver the best energy to the powder bed to facilitate densification and microstructural evolution, minimize residual stresses, and achieve mechanical, tribological, and materials integrity. 

Expertise and Skills Needed:

The intern/MSc student will have the first applied, graduate research project on both DMLS printers and be the first researcher and user of both DMLS printers.  The intern/MSc student will experience the use of DMLS in industry and academic R&D.  The intern/MSc student will actively participate in the setting of a small-medium Canadian enterprise (SME) and appreciate the use of technology in advancing the innovation and business strategy of a multinational company.  

 

For more info or to apply to this applied research position, please

  1. Check your eligibility and find more information about open projects.
  2. Complete this webform. You will be asked to upload your CV. Remember to indicate the title of the project(s) you are interested in and obtain your professor’s approval to proceed!
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