Variable Layer Heights in Wire Arc Additive Manufacturing and WAAM Information Models

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Article focuses on an important area metal products manufacturing technology based on 3D printing, in particular the WAAM technique, which in the nearest future has a real chance to be one of the main processes for producing difficult products with special functional properties for various industries. The article discusses important aspects related to the improvement of 3D printing techniques i.e. for products made out of steel.

 Proposed correction of the article:

- add the chemical composition of AWS A5.18 ER70S-6 MIG Welding Wire

 -invisible scale in Figure 10e - please enlarge it (it should be ok if you could enlarge entire picture)

Author Response

Thank you to the reviewers for helping to refine our research.

Please find our replies and revisions noted below.

Editorial changes to be more technical include the removal of extraneous words, making sentences more clear and concise, and responding to specific reviewer comments. A comparison of original text and revised changes is attached. 

Reviewers comment:

Add the chemical composition of AWS A5.18 ER70S-6 MIG Welding Wire 

Authors response:

We have added: The welding filler wire used was EN ISO 14341-A G 3Si1 with a diameter of 1.0 mm, which leads to all-weld metal chemical composition of 0.08% C, 1,2 % Mn, 0,8% Si.

Reviewers comment:

invisible scale in Figure 10e - please enlarge it (it should be ok if you could enlarge entire picture)

Authors response:

The image has been improved with a newly sized scale. The detailing of the distance representing 100,000 µm has been made larger.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for inviting me to evaluate the article titled “Variable Layer Heights in Wire Arc Additive Manufacturing and WAAM Information Models”. In this paper, a WAAM Information Model (WIM) created to collect process information into queryable databases during testing and production was pointed out. Different from the traditional wire arc additive manufacturing process for the regular shape, variable layer heights and WAAM information models have been undertaken to improve the ability to print unsupported overhanging structures in steel. The model is of great significance for preparing the unsupported overhanging structures. However, this manuscript needs careful editing by someone with expertise in technical English editing. So I strongly propose that this paper should be accepted after revision.

Comments on the Quality of English Language

Thank you for inviting me to evaluate the article titled “Variable Layer Heights in Wire Arc Additive Manufacturing and WAAM Information Models”. In this paper, a WAAM Information Model (WIM) created to collect process information into queryable databases during testing and production was pointed out. Different from the traditional wire arc additive manufacturing process for the regular shape, variable layer heights and WAAM information models have been undertaken to improve the ability to print unsupported overhanging structures in steel. The model is of great significance for preparing the unsupported overhanging structures. However, this manuscript needs careful editing by someone with expertise in technical English editing. So I strongly propose that this paper should be accepted after revision.

Author Response

Thank you to the reviewers for helping to refine our research.

Reviewer comment:

this manuscript needs careful editing by someone with expertise in technical English editing.

Authors response:

Significant revisions have been undertaken. A comparison of original text in blue and revised text in green is included in the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have conducted a comprehensive study on the development of variable layer heights in Wire Arc Additive Manufacturing (WAAM) and the creation of an Information Model. The manuscript is well-written and structured effectively. However, there are several areas that could benefit from further clarification and revision:

1.     The language throughout the manuscript should be improved.

2.     In the Introduction section, the research gap is not clear.

3.     The manuscript should provide a more detailed explanation for the selection of process parameters such as robot speed, wire feed rate, and arc length.

4.     The authors should address any potential delays associated with using the cloud-based protocol. Additionally, it would be better to present the advantages of employing this protocol in the study.

5.     The deposition rate is also influenced by the heat input. How do the authors account for this factor in their analysis?

6.     Please add a scale bar to Figure 4

7.     What was the heat input when conducting experiments with different wire feed speeds and robot speeds?

8.     The process is not solely affected by individual process parameters. Have the authors considered the interactions between multiple processing parameters?

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Thank you to the reviewers for helping to refine our research.

Please find our replies and revisions noted below.

Reviewer comments:

The language throughout the manuscript should be improved.

Authors response:

Significant revisions have been undertaken. A comparison of original text in blue and revised text in green is attached

Editorial changes to be more technical include the removal of extraneous words, making sentences more clear and concise, and responding to specific reviewer comments.

Reviewer comments:

In the Introduction section, the research gap is not clear.

Authors response:

We have added the statements:

To improve the production, systematic methods are required to control parameters and document the process. In the case of this research, an ideal method for customization of process control and recording of real time data needs to be modular to enable extension and correlated with regards to collection of data between robot, welding power source and sensors. Modular extension of the parameter control system enables access to the data model so new devices are easily integrated. Correlated collection of data enables the synchronization of information according to timestamp and tool position, so the state of the production can be analyzed at any given point in the process. An accessible, extendable, synchronized solution to this challenge, tailored for WAAM production, was created during this research.

Reviewer comments:

The manuscript should provide a more detailed explanation for the selection of process parameters such as robot speed, wire feed rate, and arc length. 

Authors response:

In section 3. Reference Geometry the following text was added

After reviewing the state of the art in WAAM research it was determined that Robot Speed and Wire Feed Speed would be tested as they combine to determine the rate of material deposition. To apply an additional factor of control to the resulting weld bead, Arc Length parameters were also selected for testing. In combination, these parameters determine the height and width of the resulting weld geometry. To test the impact of each factor, a series of plates were welded with incremental changes to each of individual parameters.

Reviewer comments:

The authors should address any potential delays associated with using the cloud-based protocol. Additionally, it would be better to present the advantages of employing this protocol in the study.

Authors response:

We have added:

4.1 Device Synchronization

Prc.IoT leverages the MxAutomation libraries to establish a connection between the command source (MCU) and the robot with data sent at 4~ms intervals. The prc.IoT framework leverages control loops through a local intranet as delays caused by the data streams being processed through the internet are variable based on location. The processing of MQTT messages does not add significantly to the 4~ms time frame of the MxAutomation data exchange. This fast reliable connection between design source and robot allows for distributed communication between machines including robot, welder, line scanner and sensors. This integration brings advantages to the WAAM process as a greater level of real world data can be ensure quality control and process optimization. 

Reviewer comments:

The deposition rate is also influenced by the heat input. How do the authors account for this factor in their analysis?

Authors response:

We have added:

3. Reference Geometry

The calculation of heat input when conducting experiments with different wire feed speeds and robot speeds is as follows: image of equation included

Reviewer comments:

The process is not solely affected by individual process parameters. Have the authors considered the interactions between multiple processing parameters?

Authors response:

The process is not solely affected by individual process parameters. Have the authors considered the interactions between multiple processing parameters?

We have added:

3. Reference Geometry

The interactions between multiple processing parameters was investigated through iterative tests of various parameter ranges. A selection of these tests are presented in this paper.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for your effort and dedication to address the comments and suggestions.