Kimes, Katerina
(2021)
Methods for Increasing Density of Binder Jet 3D Printed Tungsten Carbide-Cobalt.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Tungsten-carbide cobalt (WC-Co) is a hard, tough, and wear resistant ceramic-metal composite that is commonly used in tooling applications and is produced using traditional powder metallurgy (PM) techniques. This production method causes limitations in part quantity, and complexity. As a result, binder jet 3D printing (BJ3DP) has been considered as an alternative to the traditional PM methods. Benefits of BJ3DP include decreased manufacturing time for complex parts, greater flexibility in part complexity and quantity, ease of use, and avoidance of thermally induced stresses common in other additive manufacturing methods. To feasibly implement BJ3DP into the current production process, there must be a greater understanding of the effects of printing parameters on the final material properties of WC-Co parts. This study addresses the optimization of BJ3DP parameters to achieve green and sintered densities comparable to traditionally manufactured WC-Co parts. The design of experiments method for process optimization was implemented to study first, the effects of powder spreading parameters on the powder packing rate, and second, the effects of binder printing parameters on green and sintered part densities. Mechanical and magnetic properties were also evaluated to gain an understanding of how parts produced via BJ3DP compare to parts produced using traditional methods. It was found that layer thickness and feed ratio are the most effective parameters in changing the density of the powder in the powder bed. Effects of printing parameters were difficult to conclude due to high standard deviations of green and sintered densities. However, certain parameter sets produced clearly better results than others. Additionally, it was found that the current BJ3DP process has the capability of producing parts within acceptable density, hardness, and toughness limits for industry. Limitations of the process included poor green part strength and surface finish and is an area for further study.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
13 June 2021 |
| Date Type: |
Publication |
| Defense Date: |
31 March 2021 |
| Approval Date: |
13 June 2021 |
| Submission Date: |
12 April 2021 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
87 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Materials Science and Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Optimization, Hardmetals, Design of Experiments, Additive Manufacturing |
| Date Deposited: |
13 Jun 2021 18:47 |
| Last Modified: |
13 Jun 2023 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/40604 |
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