Setup Time Reduction of an Automotive Parts Assembly Line Using Lean Tools and Quality Tools

Round 1

Reviewer 1 Report

The paper is interesting in terms of the application of lean production concepts in productive practice. However, in order to give it the quality of a scientific paper, I think some aspects must be clarified:

- The abstract must provide clearer details with reference to the research carried out;

- I think it would be interesting for the result of the studied problem, for the authors to couple the methods approached with other specific lean production methods, such as: JEMBA with KAIZEN; standardized work with PDCA or Takt Time;

- I believe that Figures 1 and 2 must contain more details (in correlation with Apendix), in order to easily identify the places of action and intervention;

- Lines 190-196 – the authors must provide details to characterize the activities and interventions for optimizing the process. Otherwise, it can be considered a general application, without identifying the authors' contribution. Likewise, in figures 3, 4, 5;

- The authors must highlight the scientific nature of the research. I believe that, in its current form, the paper has more characteristics of an application than of a scientific research. What does the work bring?

Author Response

First of all, the authors would like to thank you for your comments and suggestions. All of them have been taken into consideration during this review.

Reviewer 1

- The abstract must provide clearer details with reference to the research carried out;

It has added more information about the results obtained with the Spaghetti Diagram and the time in every category. 

- I think it would be interesting for the result of the studied problem, for the authors to couple the methods approached with other specific lean production methods, such as: JEMBA with KAIZEN; standardized work with PDCA or Takt Time;

An analysis of standardized work with takt-time was added in the results section.  This explains how standardized work can influence Takt-Time.

- I believe that Figures 1 and 2 must contain more details (in correlation with Apendix), in order to easily identify the places of action and intervention;

For reasons of confidentiality, Figures 1 and 2 details cannot be disclosed.

- Lines 190-196 – the authors must provide details to characterize the activities and interventions for optimizing the process. Otherwise, it can be considered a general application, without identifying the authors' contribution. Likewise, in figures 3, 4, 5;

The internal tasks converted into external ones were all inserted.

- The authors must highlight the scientific nature of the research. I believe that, in its current form, the paper has more characteristics of an application than of a scientific research. What does the work bring?

In this case study SMED was supported by ERCS Analysis, Gemba Walk, Spaghetti Diagram, and Pareto Diagram. Taking into account the research done, it has not found any study that related all these tools to boost SMED implementation.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors, I congratulate you on the work you have done in practice. However, the document has opportunities for improvement that need to be carried out before it can be published. Some of these opportunities for improvement are mentioned below:

Title: I suggest changing the title in a way that you implicitly include all the lean tools, not only SMED. As you mention

“This study is further than a SMED implementation to reduce setup time. It was developed involving several Lean and Quality tools to optimize the setup time as much as possible”.

Now, as you do not develop and apply a mathematical model, how can you show that the solution you got is the optimal solution? Then, if you can not demonstrate that it is the optimal solution, remove the word “optimization”, and its derivatives, from the text.

Abstract

Line 12: You say “The main goal of this case study…”. However, you have not talked about a case study before. So, the reader does not know what case you refer to when you say “this case study”. Then I suggest you write something like this: “This paper presents a case study….”

Lines 14-16: You say “Single Minute Exchange of Die (SMED) was implemented, using other tools…”. It can be understood that SMED implementation was carried out through the use of other tools. Is this true? Or were these other tools implemented in parallel with SMED? Review and correct.

Introduction

Lines 41-42: In these lines, you say “For all the reasons above mentioned the main goal of this paper is to optimize the setup time of two welding robots”. However, the reasons you mentioned above are general reasons for any production process. You have not mentioned the specific case of the production process where the two welding robots are used. Then, you need to introduce the specific case of the production process you are improving, mention the current situation in a detailed way, and then, mention the objective.

Lines 43-44: You mention “The line chosen to develop this research was the line that represented more time wasted in changeover process”. How many lines there are? What are the times wasted in the changeover process in any line? Are these times significantly different? Include a representative sample for the times in any line.

Lines 56-69: Make complete sentences. For instance, instead of saying

“Overproduction: the offer (quantity of products manufactured) is higher than demand by customers”,

say

“Overproduction: it occurs when the offer (quantity of products manufactured) is higher than demand by customers”

Make the same for all the wastes, for all the Lean tools, and for the seven quality tools.

Line 95: In the sentence “According to Djekic and Tomasevic (2018),….”, write the citations in number style: “According to Djekic and Tomasevic [24],…”.

Line 113: You mention “…this case study…”. Remember, the word “this” refers to something that is near in distance or in time. When the reader is in line 113, you have not recently talked about the case study. Then you have to say “…..the case study presented in this paper…”.

Case study

Line 136: Instead of just saying “line”, say “production line”. Be sure to do it in all the text.

Line 137: You mention “Following, it can be observed all the steps…”. However, the reader cannot observe the steps, there are no pictures that allow to observe the steps. The steps are described, not observed.

Lines 139-174: You mention the steps you perform to achieve the goal of your project. However, you do not describe the case study in detail and what is the problem. How many production lines are running? What are the times in each of them? You must describe the process, mention the operations and their sequence; provide a sample of the times in each production line, and justify why you selected only one of them.

In this section, you have to describe the specific problem you are addressing.

3. Results

Section 3.1: You mention you have reduced the number of motions and transports. How many motions and transports there were at the beginning? How many motions and transports there are now? By what percentage were they reduced? A figure is not enough to know this information.

Section 3.3: Here, you mention that you analyzed four categories. However, you had to describe these categories before, in the case study, so that by the time the reader gets to section 3.3, he/she already knows what each category is about. For instance, I do not know what do you mean by the categories of “Main” and “Other”.

General comments

I suggest changing “Lean philosophy” to “Lean manufacturing philosophy” in the complete document. Make the same changing “line” to “production line”.

English must be improved.

More literature review is needed on quality tools, lean manufacturing tools, and wastes.

Include a Materials and methods section, so that if someone has a problem similar to the one raised in the article (which really needs to be raised), he/she will know how you carried out your project to obtain those results.

Define internal and external activities.

The writing and content should be improved, as much is left to the reader's imagination.

In the title the word "optimization" is mentioned, however, there is no proof that the result obtained is optimal.

More context is needed to provide the reader with more information about the case study.

Best wishes

English must be improved, some sentences are confusing.

Author Response

First of all, the authors would like to thank you for your comments and suggestions. All of them have been taken into consideration during this review.

Reviewer 2

Title: I suggest changing the title in a way that you implicitly include all the lean tools, not only SMED. As you mention

“This study is further than a SMED implementation to reduce setup time. It was developed involving several Lean and Quality tools to optimize the setup time as much as possible”.

Now, as you do not develop and apply a mathematical model, how can you show that the solution you got is the optimal solution? Then, if you can not demonstrate that it is the optimal solution, remove the word “optimization”, and its derivatives, from the text.

A mathematical model was not used, so the word «optimization» and its derivates were removed. 

Abstract

Line 12: You say “The main goal of this case study…”. However, you have not talked about a case study before. So, the reader does not know what case you refer to when you say “this case study”. Then I suggest you write something like this: “This paper presents a case study….”

The text has been changed according to your suggestion. 

Lines 14-16: You say “Single Minute Exchange of Die (SMED) was implemented, using other tools…”. It can be understood that SMED implementation was carried out through the use of other tools. Is this true? Or were these other tools implemented in parallel with SMED? Review and correct.

Other tools have been used to support the implementation of SMED. 

 Introduction

Lines 41-42: In these lines, you say “For all the reasons above mentioned the main goal of this paper is to optimize the setup time of two welding robots”. However, the reasons you mentioned above are general reasons for any production process. You have not mentioned the specific case of the production process where the two welding robots are used. Then, you need to introduce the specific case of the production process you are improving, mention the current situation in a detailed way, and then, mention the objective.

More specific information has been added, but it will be difficult to obtain more information for confidentiality reasons.

Lines 43-44: You mention “The line chosen to develop this research was the line that represented more time wasted in changeover process”. How many lines there are? What are the times wasted in the changeover process in any line? Are these times significantly different? Include a representative sample for the times in any line.

Lines 56-69: Make complete sentences. For instance, instead of saying

“Overproduction: the offer (quantity of products manufactured) is higher than demand by customers”,

say

“Overproduction: it occurs when the offer (quantity of products manufactured) is higher than demand by customers”

Make the same for all the wastes, for all the Lean tools, and for the seven quality tools.

The authors appreciate your comment and did the alterations that you have mentioned.

Line 95: In the sentence “According to Djekic and Tomasevic (2018),….”, write the citations in number style: “According to Djekic and Tomasevic [24],…”.

The citation has been changed according to your comment. 

Line 113: You mention “…this case study…”. Remember, the word “this” refers to something that is near in distance or in time. When the reader is in line 113, you have not recently talked about the case study. Then you have to say “…..the case study presented in this paper…”.

The text has been changed according to your suggestion. 

Case study

Line 136: Instead of just saying “line”, say “production line”. Be sure to do it in all the text.

All text has been changed according to your comment.

Line 137: You mention “Following, it can be observed all the steps…”. However, the reader cannot observe the steps, there are no pictures that allow to observe the steps. The steps are described, not observed.

The text has been changed according to your suggestion. 

Lines 139-174: You mention the steps you perform to achieve the goal of your project. However, you do not describe the case study in detail and what is the problem. How many production lines are running? What are the times in each of them? You must describe the process, mention the operations and their sequence; provide a sample of the times in each production line, and justify why you selected only one of them.

In this section, you have to describe the specific problem you are addressing.

Due to confidentiality issues, as much information as possible has been added.

3. Results

Section 3.1: You mention you have reduced the number of motions and transports. How many motions and transports there were at the beginning? How many motions and transports there are now? By what percentage were they reduced? A figure is not enough to know this information.

It was found a reduction from 54 motions to 31 and this information was added.

Section 3.3: Here, you mention that you analyzed four categories. However, you had to describe these categories before, in the case study, so that by the time the reader gets to section 3.3, he/she already knows what each category is about. For instance, I do not know what do you mean by the categories of “Main” and “Other”.

This information was added to explain the categories “Other” and “Main”.

General comments

I suggest changing “Lean philosophy” to “Lean manufacturing philosophy” in the complete document. Make the same changing “line” to “production line”.

This suggestion was accepted and implemented throughout the paper.

English must be improved.

The whole paper was reviewed by a fluent English speaker.

More literature review is needed on quality tools, lean manufacturing tools, and wastes.

This suggestion was accepted and implemented throughout the paper.

Include a Materials and methods section, so that if someone has a problem similar to the one raised in the article (which really needs to be raised), he/she will know how you carried out your project to obtain those results.

This suggestion was accepted and implemented throughout the paper.

Define internal and external activities.

This suggestion was accepted and implemented throughout the paper.

The writing and content should be improved, as much is left to the reader's imagination.

This suggestion was accepted and implemented throughout the paper, but due to confidentiality reasons, there are things that cannot be explained in a better way.

In the title the word "optimization" is mentioned, however, there is no proof that the result obtained is optimal.

This suggestion was accepted and implemented.

More context is needed to provide the reader with more information about the case study.

This suggestion was accepted and implemented.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Figures 1 and 2, but also figures 3, 4, 5, 7 represent some "black boxes". I believe that in order to understand the content of the work and to demonstrate that it is a real application, technical information is necessary that respects confidentiality. 

Author Response

Dear Reviewer,

Thank you for your comment. It has been taken into consideration during this review.

Figures 1 and 2, but also figures 3, 4, 5, 7 represent some "black boxes". We believe that in order to understand the content of the work and to demonstrate that it is a real application, technical information is necessary that respects confidentiality.

New information was added to the paper according to your commentary.

Reviewer 2 Report

Dear Authors,

Thank you for addressing the comments, your work has improved significantly and I am sure it will be of interest to readers.

In the hope that your work will be accepted for publication, I wish you success in this and future projects.

Sincerely,

The Reviewer

English has been improved.

Author Response

Dear Reviewer, 

Thank you for your review and all your comments and suggestions. Your contribution has been very important in improving our work.

Best regards,

The Authors