DESIGN AND ANALYSIS OF EXPERIMENTAL TEST RIG TO STUDY METAL ADDITIVE MANUFACTURING

Open Access
Author:
Austin, Morgan Elizabeth
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
December 10, 2018
Committee Members:
  • Rui Ni, Thesis Advisor
Keywords:
  • Metal Additive Manufacturing
  • Shields Number
  • Saltation
  • Metal Powder
Abstract:
Additive manufacturing is a layer-by-layer rapid manufacturing method that utilizes user-created computer aided design to build parts [1]. Metal additive manufacturing allows for optimization of geometries that is not usually possible by traditional manufacturing, especially in biomedical, aerospace, and other sectors [2]. One drawback to metal additive manufacturing is a rough surface finish [3], which is caused by metal powder being blown onto the part. The onset of particle motion, or metal powder blown onto a part, is characterized by the critical Shields number [4]. The critical Shields number for metal powders are unknown. To eventually study critical Shields numbers of metal powders, beyond this Thesis, a facility was designed, built, and optimized. This work endeavored to characterize the test section of the facility. Characterization involved optimizing different parameters including the baffle plate orientation, the use of a pressure pipe, the inlet pipe length, the lighting, and the amount of data taken. After optimization was complete, different inlet conditions (percentages of valve opening), which changes the flow rate of mean velocity in the test section, were studied. Increasing the valve opening, increased the maximum mean velocity from 3.87 to 5.39 to 5.98 to 6.65 m/s for valve openings of 25%, 50%, 75%, and 100%, respectively. Confidence intervals were constructed for mean velocities of the upstream, middle of observation plane, and downstream x locations for the four valve settings. Future work is needed to calculate the critical Shields number for these and other metal powders. This work has the potential to reduce the need for extensive post processing of metal additive manufactured parts.