Effect of Printing Direction and Post-Printing Conditions on Bending Properties of ULTEM 9085

Round 1

Reviewer 1 Report (Previous Reviewer 1)

All of my concerns from the original submission have been addressed. The revised submission is an improved version of the paper.

Reviewer 2 Report (Previous Reviewer 2)

no further comments.

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This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Abstract

The authors provide a concise abstract that provides a good summary of the objectives, procedures and results of the research.

1 Introduction

Good literature review of the relevant mechanical characteristics of 3D Printed materials, Fatigue properties of 3D printed and composite materials, and the effect of print orientation and processing conditions on mechanical performance.

2 Materials and Methods

2.1 Material and Manufacturing of the Test Samples

The material and manufacturing process of the test samples are described in this section. Figure 1 shows the cross-sections of fractured samples after cooling for the three different print orientations. It is not clear if these ‘fractured’ samples are fractured during the manufacturing process or are these images taken after mechanical testing. Please clarify. If they are images taken after testing, it may be less confusing to put this figure in one of the results sections and show pre-testing images in this section.

2.2.2 Morphological Analysis

Line 132  Instead of stating “The specimens were used…”, should this be “The specimens were imaged…” ‘Used’ seems out of place here.

2.2.3 Static Bending Tests

Equations 1 and 2: (Editor Question?) Is the comma necessary after equations 1 and 2? It looks like a ‘prime’ symbol, especially in equation 2, which was initially a bit confusing.

3 Results

3.1 Morphological Analysis

Line 190-191 The authors state that the cooling history of the Ultem samples did not lead to large differences in morphology. However, the morphology in Figure 3a looks significantly different when compared to Figures 3b and 3c. The voids in figure 3a look like they are collapsed or is this an effect of the image/specimen orientation? Please explain.

Line 202-203 Add a reference to Figures 5a-c in the text.

3.3 Fatigue Tests

Lines 302-304 The authors mention that the “samples printed in the Z direction were printed with minimal side walls which were cut before the tests but still could affect the testing results”.  However, in Section 2.1, the authors stated that the samples were printed without walls. If machining was required to remove side walls for the z-printed samples, this should be mentioned in Section 2.1.

Reviewer 2 Report

Authors present the experimental characterization of the mechanical properties under bending of FFF-structures made out of Ultime 9085. In general, the work has limited scientific contribution, as various similar works have been previously published. The following issues should be attended before this can be further considered.

-          the review of literature is limited. Several works on the flexural properties of FFF-structures have been published and these are not cited.

-          Also, authors didn’t discuss what the most relevant references have done both in fatigue and static loading conditions, they merely (and superficially) mention that these have been done previously.

-          Line 98: the word filaments is often used for the raw material (prior printing), i think here the word "rasters" suits better

-          Line 99: what about the dimensions for the static tests?

-          Authors must extend their discussions, as they only mention what we have already saw in the figures. For example Lines 217-218.

-          From figure 6, we can see that there’s no significant effect of the temperature on the mechanical response. Why? Please elaborate.

-          Lines 223-229: shallow and limited discussion. not in the level of a scientific paper. authors are not saying anything relevant.

-          Figures 8 and 9: why not presenting it in a loglog scale as many SN curves.

English is readble, no major issues detected.

Reviewer 3 Report

see attached pdf

Comments for author File: Comments.pdf