Innovative Methods for Small Mixed Batches Production System Improvement: The Case of a Bakery Machine Manufacturer

Round 1

Reviewer 1 Report

improve the quality of figure 6

Author Response

Dear Reviewer,

thank you for your proposals to improve the manuscript. The following revision was done according to comments:

Introduction

Line 143: "Despite these possibilities, many non-automotive industry organizations still record their measurements in paper forms and underuse the power of data to reduce the material and energy consumption what is a necessary condition for sustainability on the organizational level [8]."

Line 159: "Nowadays, the necessity to modify production towards to more sustainable business and according to individual customer specifications and preferences, the "Lean" paradigm [13] [14] and Six Sigma philosophy is increasingly being applied, because organizations need to focus on process improvement [15] [16]."

Line 169: "The rest of the paper is structured as follows: Section 2 contains the literature survey of tools and methods used for SMB production system improvement with a focus on using intelligent technologies. Section 3 describes the problem in the bakery machine manufacturer and introduces the newly developed LSS-SMB method. This section also contains a detailed description of data collection and analysis during the two years of project duration. In Section 4, we continue by presenting the key results of our case study with the support of tables and figures. Section 5 discusses our findings, and Section 6 presents the key conclusions from the entire paper."

Figure 6: It is re-draw, and now it is Figure 5 (a) (b) (it was a mistake in numbering). 

If the language adjustments are not sufficient, we will ask for the MDPI  professional English editing service.

Reviewer 2 Report

This paper examines the application of historical and real-time data for prediction of future manufacturing data and quality characteristics in the context of the Lean Six Sigma methodology.  It incorporates ANN, machine learning and Quality 4.0 concepts to LSS methodology.  The feedback from the prior peer review was incorporated and greatly improved the paper.  Literature review is stronger.  The details surrounding the procedure are clearer, especially for the non-LSS-practitioner.  I think this paper will fit well within the special issue for Actual Trends in Logistics and Industrial Engineering.

Author Response

Dear reviewer,

thank you for your proposals to improve the manuscript. Manuscript is revised according to Reviewer 3 comments, and if the language adjustments are not sufficient, we will ask for the MDPI professional English editing service.

Reviewer 3 Report

I have reviewed the manuscript "Innovative methods for Small Mixed Batches Production System Improvement: Case of a Bakery Machine Manufacturer", Manuscript ID: sustainability-872379 that has been submitted for publication in the MDPI Sustainability Journal and I have identified a series of aspects that in my opinion must be addressed in order to bring a benefit to the manuscript.

In this paper (of Case Report type), the authors present the Lean Six Sigma (LSS) methodology for Small Mixed Batch (SMB) production system. The authors extend the standard set of LSS tools by making use of artificial neural networks and a machine learning approach. The LSS-SMB methodology is illustrated in the case study of a bakery machine turning process.

I consider that the article will benefit if the authors take into account the following remarks and address within the manuscript the signaled issues:

Overall comments regarding the manuscript.

The Manuscript ID: sustainability-872379 is interesting, but it still remains an aspect that must be clarified by the authors, namely the fact that they must assume more clearly their own results. I consider that the authors must assume more clearly in the paper their original contribution by specifying this fact and by highlighting the fact that starting from a certain point there are presented the original and novel aspects of their paper. The authors must state more clearly their original methods, their original results and conclusions, the novelty of their study. In the current form of the paper, this aspect is unclear.

Specific comments regarding the manuscript.

Remark 1 – lines 20-32, the "Abstract" of the paper. In the "Abstract" of the paper, the authors must present in a clearer manner the following aspects: the background, the methods, the main findings, the conclusions, as in the actual form of the manuscript, the abstract offers information related only to some of these aspects and even so, their delimitation is unclear.

Remark 2 – line 87, the "Introduction" section. "Our research started with a literary survey in Emerald Insight and MDPI databases…" I do not contradict the value of this approach, or its relevance in this context, but I consider that the article under review will benefit if the authors explain in the paper what was the criteria in their research methodology based on which they have decided to analyze only papers from the two above-mentioned sources.

Remark 3 – the gap in the scientific literature. After having performed a critical survey of what has been done up to this point in the scientific literature, the authors must identify and state more clearly in the paper a gap in the current state of knowledge that needs to be filled, a gap that is being addressed by their manuscript. This gap must also be used afterwards, in the "Discussion" section of the manuscript as well, where the authors should justify why their approach fills the identified gap in rapport with previous studies from the literature.

Remark 4 – the "Introduction" section. At the end of the "Introduction" section, the authors should present the structure of their paper, under the form: "The rest of the paper is structured as follows: Section 2 contains…".

Remark 5 – subsection "3.4. Data analysis", lines 317-320. "The second model uses feedforward ANN described in section 2.3 trained with Levenberg-Marquardt backpropagation algorithm. The network has one hidden layer with ten neurons with a hyperbolic tangent sigmoid activation function. The output layer has one neuron with a linear activation function." As the authors have used an Artificial Neural Network approach, I consider that the paper will benefit if the authors present more details regarding the results obtained during various tests, for different training algorithms, for all the different number of neurons and epochs tested and especially the training time for each test, until they have obtained the configuration that has provided the best results. The information can be summarized in a table and if it becomes too long, the authors can restrict it in the paper to ten main experimental runs, and a complete table with all the experimental runs must be inserted in the Supplementary Materials file of the article. The authors must specify in the paper how often does the network need to be retrained/updated and how did the authors tackle the need of retraining/updating the network. How is the data encountered stored for subsequent updates of the network?

Remark 6 – subsection "3.4. Data analysis", issue regarding the dataset. The authors must provide more details regarding the way in which they have solved the problems related to missing data or abnormal values if they have occurred.

Remark 7 – the "Discussion" section. In the actual form of the paper, the "Discussion" section is rather a "Results" one, as in this section the authors have provided a table containing the results of their study. Actually, this section contains a large table, spreading along page 12 and a half of page 13, table through which the authors have presented a large amount of information, without analyzing it. In fact, the table is not used in order to synthesize the information but rather to present it. The authors must explain and analyze in detail all the tables and figures that have been inserted within the manuscript, it is not suitable to put the reader in the situation of interpreting, analyzing, continuing or refining the study from the manuscript under review.

Remark 8 – the "Discussion" section. In order to validate the usefulness of their research, in the "Discussion" section, the authors should make a comparison between their study from the manuscript and other ones that have been developed and used in the literature for the same or similar purposes. There are a lot of valuable studies in the scientific literature related to the subject of the manuscript to which the authors can compare to and this comparison will highlight even more the insights that their paper has brought in contrast to the existing studies. This comparison is mandatory in order to highlight the clear contribution to the current state of knowledge that the authors have brought.

Remark 9 – the "Discussion" section. In the "Discussion" section the authors should also highlight current limitations of their study and briefly mention some precise directions that they intend to follow in their future research work. The authors should highlight whether, or to what extent they have managed to address the necessity identified within the "Introduction" section. In this section the authors must present in a clearer manner the learnings and insights of their research.

Remark 10 – the "Discussion " section. The paper will benefit if the authors make a step further, beyond their approach and provide an insight at the end of the "Discussion" section regarding what they consider to be, based on the obtained results, the most important, appropriate and concrete actions that the decisional factors and all the involved parties should take in order to benefit from the results of the research conducted within the manuscript as to attain the ultimate goal of sustainability.

Other remarks:

• Figure 5 and its reference are missing from the manuscript. After Figure 4 comes Figure 6.
• The credentials of the last but one author contain its own name along with the details regarding the school, university, location, and e-mail address.
• The authors must take into account the recommendations from the MDPI Sustainability Journal's website regarding the format of the papers, by using the Microsoft Word template or LaTeX template to prepare their manuscript. In the actual form of the paper, a part of these recommendations has not been taken into account and therefore, the reading of the manuscript is affected, for instance: in the text of the paper, the parenthesis containing the references should be of the forms [1–3] or [1,3], instead of the actual form (for example, the authors have written [4] [5] at line 45, [9] [10] at line 59, [35] [40] [41]  at line 198 and the same situation in many other places along the paper).

Author Response

Dear Reviewer,

thank you for the chance to improve the manuscript and your valuable comments. The following revision was done:

Remark 1: Abstract. The background, methods, main findings and conclusions was added.

Remark 2 – line 87, the "Introduction" section: "... survey in Emerald Insight and MDPI databases" was omitted as literature reviews were done also from other databases. More literary sources were added.

Remark 3 – Gaps are described in:

Section 2.1 "Intelligent technologies and real-time quality control and improvement are not yet an integral part of LSS practice."

Section 2.2 "The concept of intelligent SPC uses gathered data, artificial neural networks, and machine learning to improve the automatic detection of the out of control state of the process, or to estimate the process mean value and variance [32] [33] [34]. Authors use intelligent technologies only for the detection of an adverse condition, but not for its prediction or prevention."

Section 2.3 "Authors in [29, 37-45, 47-49] use prediction models for dimensional deviation and surface roughness prediction only. They do not deal with the integration of models into the process of quality control."

The critical survey in sub-chapters 2.1, 2.2. and 2.3 implies that intelligent technologies are not fully integrated into traditional methods of Lean Six Sigma and process quality control. Therefore our research is going to address this issue to further move on industrial processes towards business sustainability.

Remark 4: Added to the 1. Introduction. "The rest of the paper is structured as follows: Section 2 contains the literature survey of tools and methods used for SMB production system improvement with a focus on using intelligent technologies. Section 3 describes the problem in the bakery machine manufacturer and introduces the newly developed LSS-SMB method. This section also contains a detailed description of data collection and analysis during the two years of project duration. In Section 4, we continue by presenting the key results of our case study with the support of tables and figures. Section 5 discusses our findings, and Section 6 presents the key conclusions from the entire paper."

Remark 5: 3.4. Data analysis. Explanation is added to this section: "Statistical results for three training algorithms Levenberg-Marquardt, Scaled Conjugate Gradient, and BFGS Quasi-Newton, are summarized in the new Table 5. The network showed very similar results for 4 to 10 neurons in the hidden layer. Data is in Appendix B, Table 4. Each row summarizes results from 30 individual runs. The complete table contains 1440 rows, therefore is not included."

Remark 6:  3.4. Data analysis, issue regarding the dataset. It was concluded that the operator and the measuring device influence measured data from the year 2017 significantly. Therefore, no more in-depth data analysis was conducted for these measurements.

Remark 7: The original section Disscussion was renamed to Results and re-structuralized. The original Table 5 is divided to three separate tables, which are explained in detail. A New "Discussion" section was added.  

Remark 8: Discussion. A comparison of literature sources and newly developed LSS-SMB method is added to the Discussion section.

Remark 9: Discussion – Limitation: “The limitation of the LSS-SMB method is that the prediction models are based on data from the past, and the real future may be different. Therefore, intelligent SPC will also have to be used. The diagram in Figure 6 is incomplete because it does not directly determine the lathe machine set-up”. The future direction of our research is described on line 703.

Remark 10: Discussion. Concrete action that involved parties should take to benefit from results are in line 706. 

If the language adjustments are not sufficient, we will ask for MDPI professional English editing service. 

Round 2

Reviewer 3 Report

I have reviewed the revised version of the manuscript "Innovative methods for Small Mixed Batches Production System Improvement: Case of a Bakery Machine Manufacturer", Manuscript ID: sustainability-872379 that has been submitted for publication in the MDPI Sustainability Journal and I can conclude that the authors have addressed the most important signaled issues, therefore improving the manuscript.