Keywords

powder bed fusion, polyamide-12, sintering, mechanical properties, polymer sintering, porosity, laser sintering

Abstract

In powder bed fusion additive manufacturing (AM), the fusing process is temperature and time dependent. However, little work has been done to understand how different processing temperatures and times might impact the mechanical properties at longer sintering times than are typical in laser sintering (LS) systems. Prior results with projection sintering have shown that heating for longer times (>1s) improves part toughness compared to laser sintering. In this work, Large Area Projection Sintering (LAPS) is used to sinter entire layers of material simultaneously over the course of a few seconds with spatial control of layer temperature. This work evaluates the effect of time and temperature on the mechanical properties of parts sintered from PA 2202 (Polyamide 12) powder. Toughness is shown to increase significantly with longer sintering times (5-8 s) and higher temperatures (195-205 °C) with elongations at break (EaB) over 100% and strengths of up to 51.7 MPa. This represents a small increase in strength and an order of magnitude increase in elongation at break relative to LS datasheet values for the material. Peak mechanical properties are achieved sintering at lower temperature (195 °C) and longer times (5-8 s). The density of the samples that maximize toughness and strength is greater than 1.02 g/cm3 compared to datasheet values of 0.98 g/cm3. Porosity elimination could be a mechanism for improved performance though it does not fully explain the improvements in strength and ductility.

Original Publication Citation

Justin Nussbaum, Taranjot Kaur, Julie Harmon, and Nathan B. Crane, “Impact of Sintering Time and Temperature on Mechanical Properties in Projection Sintering of Polyamide-12,” Additive Manufacturing, Published 10/09/2020, DOI: 10.1016/j.addma.2020.101652.

Document Type

Peer-Reviewed Article

Publication Date

2020-10-09

Publisher

Additive Manufacturing

Language

English

College

Ira A. Fulton College of Engineering and Technology

Department

Mechanical Engineering

University Standing at Time of Publication

Full Professor

Available for download on Wednesday, June 14, 2023

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