Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List

ETD Abstract Container

Abstract Header

Modeling and Optimization of Powder Based Additive Manufacturing (AM) Processes

Paul, Ratnadeep

Abstract Details

, PhD, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
Metal powder based Additive Manufacturing (AM) processes are increasingly being accepted across several industries such as aerospace, automobile, medical, consumer products and electronics systems. However, the most pressing issues faced by AM technology today are concerns in achieving part accuracy and excessive material and energy utilization. Therefore, a comprehensive part-level approach analyzing the relation between the different physical phenomena occurring during the manufacturing of a metal AM part is required. A comprehensive virtual manufacturing model has been developed for simulating the surface of parts manufactured using metal powder based AM processes. The virtual manufacturing model simulates the geometry of the AM part using computational geometry techniques. Points are sampled from the surface of the simulated parts simulated and used for calculating the Geometric Dimensioning and Tolerancing (GD&T) errors and also for correlating these errors to the input parameters. The geometric virtual manufacturing model is further augmented by material shrinkage and thermal deformation error models. The shrinkage model estimates the effect of material shrinkage in AM part errors while the thermal deformation model analyzes the combined effect of shrinkage and thermal deformation on part errors. The Stereolithography (STL) file format approximates part surfaces with planar triangular facets resulting in errors in the manufactured part. Another file format, called Additive Manufacturing File (AMF) format uses recursive sub-division of curved triangles into planar triangles which however, leads to the same approximation error. This research introduces a new format which uses curved Steiner patches for approximating part surfaces and generating the different slices. Several test surfaces and parts are virtually manufactured using the Steiner format and the GD&T errors of the manufactured parts are calculated and compared with those parts manufactured using the STL and AMF representations. Support structures are additional material sintered during the manufacturing of an AM part for supporting internal cavities and overhangs. This study presents a voxel based algorithm for calculating the location and the volume of support structures used in AM processes and correlating them to the process parameters. Two parametric energy models have also been developed in this research: one for calculating the total process energy in AM processes which do not use supports and another for those processes which require supports for overhangs and holes. The first energy model uses a convex hull approach while the second model applies the voxel algorithm to develop a predictive model for calculating the total energy expended in AM processes. Finally, optimization models have been developed which minimize part errors, part strength, material utilization and energy expenditure in metal powder AM process by varying the process parameters and calculating their optimal values. The optimization algorithms will assist AM practitioners in producing error free parts the first time ("first part right"), thereby eliminating the trial and error process currently associated with manufacturing an AM part. They will also reduce the material utilization and the energy footprint of powder based AM processes, thereby driving down the costs associated with producing parts by metal powder based AM processes.
Sundararaman Anand, Ph.D. (Committee Chair)
Todd J. Rockstroh, Ph.D. (Committee Member)
Hongdao Huang, Ph.D. (Committee Member)
Sundaram Murali Meenakshi, Ph.D. (Committee Member)
David Thompson, Ph.D. (Committee Member)
202 p.

Recommended Citations

Citations

  • Paul, R. (n.d.). Modeling and Optimization of Powder Based Additive Manufacturing (AM) Processes [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378113813

    APA Style (7th edition)

  • Paul, Ratnadeep. Modeling and Optimization of Powder Based Additive Manufacturing (AM) Processes. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378113813.

    MLA Style (8th edition)

  • Paul, Ratnadeep. "Modeling and Optimization of Powder Based Additive Manufacturing (AM) Processes." Doctoral dissertation, University of Cincinnati. Accessed MARCH 29, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378113813

    Chicago Manual of Style (17th edition)