Effect of Geometry and Size on Additively Manufactured Short-Fiber Carbon-Nylon Composite Under Tensile Loading

Area of Science:

• Materials Science
• Additive Manufacturing
• Mechanical Engineering

Background:

• 3D printing processes, particularly extrusion-based methods, create parts with inherent line structures.
• Variations in extrusion line shape and size raise questions about the comparability and repeatability of printed part properties.
• Tensile strength is a critical property for engineering materials, influencing their suitability for various applications.

Purpose of the Study:

• To investigate the influence of specimen geometry and size on the tensile strength of 3D printed parts.
• To determine if extrusion line size (nozzle diameter) affects tensile strength.
• To compare the tensile strength of 3D printed parts with different internal structures (walls vs. infill).

Main Methods:

• Utilized chopped carbon-fiber-reinforced nylon, a common engineering material.
• Printed four main specimen groups: solid walls only and infill only.
• Employed two nozzle sizes (0.4 mm and 0.8 mm) to create different extrusion line structures.
• Conducted tensile strength tests on all printed specimens.

Main Results:

• Specimen geometry and size did not significantly influence tensile strength across the tested groups.
• Specimens composed solely of walls demonstrated higher tensile strength compared to those with only infill.
• Parts printed with a 0.4 mm nozzle exhibited greater tensile strength than those printed with a 0.8 mm nozzle.

Conclusions:

• The geometry and size of specimens have a negligible impact on the tensile strength of 3D printed nylon parts.
• Internal structure (solid walls vs. infill) and extrusion line size (nozzle diameter) are key factors influencing tensile strength.
• Optimizing printing parameters, such as nozzle size and internal structure, is crucial for maximizing the mechanical performance of 3D printed components.