Mechanical and Thermal Properties of Multilayer-Coated 3D-Printed Carbon Fiber Reinforced Nylon Composites

Round 1

Reviewer 1 Report

The article presents topical issues of creating multilayer composites on a substrate obtained by the additive method. The embedding of copper mesh is widely used in aeronautical composites obtained by the autoclave method. The use of additive technologies does not allow obtaining such products in one technological transition. As an object of research, the authors consider the details of the nodes of robotic manipulators, from which it is necessary to remove heat. The article presents the results of experimental and theoretical studies of multilayer composite materials. However, according to the results of studying the materials presented in the article, several questions arose (materials in the file). Solving them will improve the quality of the presented work.

Due to overall comments I suggest major revision.

Comments for author File: Comments.pdf

Author Response

The article presents topical issues of creating multilayer composites on a substrate obtained by the additive method. The embedding of copper mesh is widely used in aeronautical composites obtained by the autoclave method. The use of additive technologies does not allow obtaining such products in one technological transition. As an object of research, the authors consider the details of the nodes of robotic manipulators, from which it is necessary to remove heat. The article presents the results of experimental and theoretical studies of multilayer composite materials. However, according to the results of studying the materials presented in the article, several questions arose (materials in the file). Solving them will improve the quality of the presented work.

Due to overall comments I suggest major revision.

Reply: Thank you for the constructive comments. It is true that embedding copper mesh and carbon fabric is an augmented process after 3D printing. The advantages of 3D printing of carbon fibre composites are apparent owing to the possibility of making complex shapes and smart structures. The enhancement in thermal and mechanical resistance outweighs the cost of embedding copper mesh and fabric. The questions marked in the file have been addressed.

1. In the introduction, the authors do not use links to articles from highly rated journals of the composite industry, which significantly reduces the value of the presented material ( Composite Part A , B , Composites and Advanced Materials, Journal of Composites，Polymers Science This fact significantly reduces the value of the presented material. , etc ) . The list of sources should be expanded

>>More recent references are added [7-9;12-14;30-31]

2. What kind of the fabric did the authors use (plane, twill, unidirectional, etc.). will help to reproduce the experiment with other analog materials.

>>It is twill carbon fabric that was used. This is clarified in the paper page 2 Materials section.

3. In the section “Sample preparation” there are several questions: It is unclear what kind of film the authors cut out and for what. If it's for a vacuum bag, then write about it that way. There is no mention of this object in the materials authors like the curing time of the glue to be specified. Also write “Once the base adhesive was completely cured…”, section. I would also it is necessary to specify the curing time. How was the thickness of the adhesive layer controlled? In my opinion, this section should be written in more details.

>>The paragraph is revised as suggested. The plastic film is a common PE film. A PE/PA copolymer vacuum bag is used. The adhesive used is epoxy based resin as described in page 2, Materials section. The curing time is described in the now Composite sample preparation section in page 3, i.e. 1h at 60°C plus 12 h at room temperature.

4. In section 3.1 Microstructural Analysis, the authors write "The pore size of the copper mesh directly affects the structure of this composite material, which is because the pores of the slightly larger copper mesh can make more carbon fiber fabric interwoven in the larger copper mesh surface and pores, forming a composite material with a complex reinforced phase structure". The figure shows only 1 structure of 1 composite. Snapshots of the structures of all composites allow us to obtain a more complete evidence base. Images taken with a larger magnification, for example using SEM, would provide more information about the areas of adhesion between the layers.

>> Images are added in page 5, section 3.1.

5. The evidence base of the obtained phenomena is presented in the discussions, but there is no comparison with the results of other authors. It is necessary to add links to this part and show how the authors' results differ from the existing ones.

>> Results of exactly the same materials have not been reported. However, enhancement of flexural properties by fiber wrapping on plastic components has been reported [31] as described in page 3, section 3.1.2.

6. The erroneous abbreviation SCFRP is used in page 11, line 7.

>>Corrected as sCFRP.

Reviewer 2 Report

This manuscript studied the mechanical and thermal properties of hybrid composites. The copper mesh and carbon fiber can improve the thermal conductivity and strength of the printed composites. Several points need to be further explained in the context.

1.     The major advantage of the 3D printed composite is its ability to form complicated shape component. In this study, can the coating method be extended to the complicated shape component. The authors should commend on this point.

2.     In page 1, “However, the moderate mechanical performance and poor thermal conductivity…and heat resistance requirements [14]”. Should the “heat resistance” be heat conduction?

3.  In page 2, five line, should the ”thermal electrical” be misprint of “electrical”?

Minor modification is required.

Author Response

This manuscript studied the mechanical and thermal properties of hybrid composites. The copper mesh and carbon fiber can improve the thermal conductivity and strength of the printed composites. Several points need to be further explained in the context.

1. The major advantage of the 3D printed composite is its ability to form complicated shape component. In this study, can the coating method be extended to the complicated shape component. The authors should commend on this point.

Reply: Yes, it has been applied to a 3D printed tubular robotic arm which has been reported previously.

2. In page 1, “However, the moderate mechanical performance and poor thermal conductivity…and heat resistance requirements [14]”. Should the “heat resistance” be heat conduction?

Reply: Yes, corrected.

3. In page 2, five line, should the ”thermal electrical” be misprint of “electrical”?

Reply: Thank you. This is corrected.

Round 2

Reviewer 1 Report

Accept in present form

Reviewer 2 Report

I have no further question.