High-Throughput Fused Filament Fabrication of PLA: Effects of Melting Zone Length and Filament Diameter on Extrusion Force and Volumetric Flow Rate

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper presents a comprehensive examination of the relationship of melting zone length and filament diameter on extrusion force and volumetric flow rate for high-throughput FFF of PLA, and develops a numerical model that substantially confirms the experimentally observed trends.

The arguments are well presented, the data are numerous and the paper is ready for publication. Some few notes could be focused:

• Line 64-75: the period should be simplified to be more comprehensible;
• Line 89: “is” instead of “as”;
• Line 97-100: please refer the description of L to a figure of the paper;
• Figure 7: could it be possible to turn it in a colored figure?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This document presents a study of the effect of the Melting Zone Length and Filament Diameter on Extrusion Force and Volumetric Flow Rate. Document is well written, uses a proper methodology, and presents results using good supporting material. 

The study is a good reference for those interested in improving the printing parameters, in particular with a novel approach of changing the length of the nozzle. The study analyzes two of the most common printing diameters (1.75 and 2.85). 

Author Response

We sincerely thank the reviewer for the time and effort devoted to evaluating our manuscript. We greatly appreciate the favorable assessment and are glad that no further revisions were considered necessary.

Reviewer 3 Report

Comments and Suggestions for Authors

This article combines simulation and experiment to study the FFF process parameters. I have the following questions and suggestions:
1. The melt deposition molding of PLA has become mature and widely commercialized. The purpose of this article is to increase the volumetric flow rate and improve printing speed? What is the current printing efficiency of mature commercial printers? Can you make a comparison?
2. The commonly used filament diameter is 1.75, why choose 2.85 in this article? Are there any other diameters available for selection?
3. Besides temperature, length, and force, does nozzle diameter affect volumetric flow rate?Does the nozzle diameter have a greater impact? Please explain.
4. The figures in this article are mostly schematic diagrams and experimental result curves. Can you add photos of the experimental equipment during on-site printing, that is, how the force sensor is installed? How is force measured?  How is volumetric flow rate measured? and so on.
5. What software platform is used for simulation? Specific modeling parameters can be described in more detail.
6. It is recommended to use color for Figures 7, 8, and 9, consistent with others.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript is acceptable.