Closed-Loop Control Applied to the Injection Moulding Process—An Industry 4.0 Refurbishment Case Study
Round 1
Reviewer 1 Report
The article describes the Closed-loop control applied to the injection moulding process – an Industry 4.0 refurbishment case-study. Although authors have covered all the aspects and explain them appropriately, the following need to be consider for the modification and possible publication of the proposed work.
1. Line 27 - 28: Industrial Internet of Things (IIoT) and Industry 4.0 are the different things. IIoT is the subset or crucial component in Industry 4.0. Kindly restructure the sentence accordingly.
2. Line 112-113: Blank?
3. PVT nomenclature is missing.
4. The article needs an English grammar and spell check.
5. The conclusion should briefly explains the results obtained (numerically). Reframe the conclusion accordingly.
Author Response
Dear Reviewer,
Many thanks for your comments.
Concerning item 1, you’re absolutely right. The sentence will be restructured to reflect what is IIoT within the Industry 4.0 context.
Line 112-113 will be deleted (item 2).
On item 3, PVT stands for Pressure, Volume and Temperature and it designates a typical laboratory trial applied to thermoplastic materials. The behaviour of the thermoplastic material, in particular, specific volume and temperature are monitored at constant pressure. Typically, this essay is performed for several pressure values, ranging from ambient pressure to service pressures used on the injection moulding process.
Concerning item 4, please kindly explain which sentences are confusing. Maybe the technical language is correct but further explaining is required.
On your last item (5), we are experiencing some problems since the company where we made the implementation was bought by another company. Nevertheless, we’ll do our best to improve the conclusions.
Best regards,
The authors
Reviewer 2 Report
According to the main content, the main novelty of this work is unclear. However, authors can improve some weaknesses of this research based on following comments:
A) Introduction Section should be extended with details to show main novelty of the proposed method, adding some existing and relevant references and finally adding main organization of the paper.
B) Please discuss more clearly some new relevant case studies in the literature review:
- The role of additive manufacturing in industry 4.0: An exploration of different business models
- Towards decision support systems for energy management in the smart industry and Internet of Things
- Ultrasound sensors for process monitoring in injection moulding
C) in Some cases authors have written "molding" but in other parts they have written "moulding". Please justify corrections for this issue.
D) Based on Figure 5 as Local or remote services management through a web-based platform, please explain exactly each component of this figure with details.
Author Response
Dear Reviewer,
Many thanks for your comments.
Concerning item A and since it relates to your prior observation, we will highlight the main novelty of the paper. Therefore, Introduction will be extended and the structure of the paper will be inserted.
For item B, the reference related to the paper entitled “The role of additive manufacturing in industry 4.0: An exploration of different business models” discusses the different business models for plastic or plastic-like parts. The cost per part is different for each approach but the time-to-market is also important.
The reference “Towards decision support systems for energy management in the smart industry and Internet of Things” is used to support the purpose of the proposed algorithm to optimize the injection moulding process and improve the energy usage.
Finally, the reference “Ultrasound sensors for process monitoring in injection moulding” is relevant to present other solutions for mould sensoring. In our case-study, the sensors used are contact sensors, meaning that it needs to be assembled on the mould cavity to retrieve data. Ultrasound sensors provide additional flexibility that contact sensors cannot.
The issue on item C is clearly a mistake from the authors. The term “moulding” is the intended one, since we are Portuguese and, therefore, British English should be used.
Concerning item D, the explaining of Figure 5 will be improved.
Best regards,
The authors
Reviewer 3 Report
The ABSTRACT section is well–structured, is informative, can stand alone and covers the content. The aims and objectives of the research are well-presented. The conceptual approach on this research is focused on the pressure loss control inside the mould cavity and melt temperature by means of injection speed control.
The paper is structured properly. The structure of paper is good, and the additions bring improvements. The basic structure of a typical research paper is the sequence of Introduction, Methods, Results, and Discussion. The paper present preliminary results on this case-study proved that this solution provides suitable response to the processing variations imposed, resulting on optimized plastic parts. External factors such as processing equipment malfunctions, environmental variations or tools mis-use require qualified professionals to handle these issues or diagnosing systems to detect them on an early stage to avoid part production on unsuitable processing conditions.
The INTRODUCTION section provide the necessary background information. The section is well–documented. Also, the aims and objectives of the research are well defined. It is comprehensive with the state of research in the field, relevant for this subject in area of current research on the injection of thermoplastics, providing access to a broad range of products for several industries such as automotive, electronics or medical. Literature review provides comprehensive information about the current state of research.
The METHODOLOGY / MATERIALS & METHODS section is relatively well described and include detailed information about the implementation details. This section include all the technical details of the experimental setup, measurement procedure, and details of how the methods were validated. Overall, this section is technically and fairly detailed. The experimental approach carried out in this research work was based on the interpretation of internal cavity pressure to determine the most suitable injection speed profile to impose on the injection cycles. Prior research introduced a new process methodology based on the PVT behavior of polymer for injection molding. The injection trials conducted on the setup phase were initiated using an injection speed profile originated from numerical simulations that provided suitable responses to the local pressures drops caused by material flow on specific locations.
The body of paper describe the important RESULTS of the research on polyester waste from the garment industry as reinforcement in cementitious composites with non-structural uses. For this study, the Process Control System (PCS) developed for this research work consists on a cyber-physical system that fully integrates the assets existent on the injection moulding cell and generates and manages the processing data retrieved from mould sensors, injection equipment and other peripheral equipment, specially focused on injection moulding process optimisation. The principle of interoperability is applied inside the injection moulding cell. Therefore, this injection moulding cell is flexible and it can be rapidly reconfigured to comply with future product changes. The interaction with all the assets on the injection moulding cell is ensured by a communication layer that constitutes the management interface applied to the injection machine. The PCS evaluation was performed by injection experiments and assessment of the overall quality of the plastic parts produced under the processing conditions generated by the PPU, consisting on the part defect analysis and dimensional analysis of part’s key features.
The CONCLUSION section succinctly summarize the major points of the paper, presented concisely and to the point. The authors fairly concludes in just a few sentences given the rich discussion in the body of the paper. Overall, this section is well-concluded.
The Tables are representative and the Figures & Graphs have good qualities.
The list of REFERENCES is long and relatively well chosen. The entire bibliography is current.
I have not detected any mistakes.
Author Response
Dear Reviewer,
Many thanks for your comments.
Best regards,
The Authors
Round 2
Reviewer 2 Report
Authors answered my comments in the revised version.
