*Article* **Optimization of the Sustainable Distribution Supply Chain Using the Lean Value Stream Mapping 4.0 Tool: A Case Study of the Automotive Wiring Industry**

**Yousra El Kihel 1, \*, Ali El Kihel <sup>2</sup> and Soufiane Embarki 3**


**Abstract:** The transformation to Supply Chain (SC) 4.0 promises new opportunities for companies to gain competitiveness. The Lean Value Stream Mapping (VSM) tool allows the supervision of all the processes of the entire SC, from which we can identify the different types of waste that hinder the competitiveness of the SC. Following the existing problems detected with the help of a diagnostic, we will propose a new process design by integrating 4.0 technologies to modernize the company. For our case study, we treat the multinational SC of Automotive Wiring Equipment Morocco, where we will focus on the downstream part of the SC composed of the warehouse and the different stages of road and sea transport until the final delivery in Austria. Then, we will consider the opportunities offered by each country in terms of logistics competitiveness. In this research work, we will show how Lean VSM4.0 will contribute to sustainable development by integrating the three pillars economic, environmental, and social. With the Lean VSM 4.0 tool, all logistic processes will be visualized, from which improvements could be obtained, especially the optimization of the lead-time, the cost, the energy consumed, and the follow-up of the products during the whole SC while reducing accidents.

**Keywords:** VSM; durability; logistics 4.0; methodology; automobile; wiring

#### **1. Introduction**

Currently, there is increased competition between companies in the automotive industry. The automotive equipment manufacturers, cabling, and others are characterized by very high competitiveness and diversity of products and distribution on an international scale. Morocco has become the first construction hub on the African continent, ahead of South Africa and Egypt, with distribution on an international scale [1]. Therefore, it is necessary for each company to adapt to new technological changes to increase production and find solutions for improving the flexibility of its distribution system by delivering to customers at a low cost with a deadline and optimal quality [2].

Enterprise 4.0 refers to a new generation of connected and intelligent factories. It is a digital transformation characterized mainly by intelligent automation and the integration of new technologies into the enterprise value chain, giving life to an interconnected enterprise 4.0 where machines, products, and people interact [3]. The digitization of the SC, according to Industry 4.0, therefore, promises new opportunities to develop more efficient supply, production, and distribution lines, while supervising the entire supply line.

Digital twins play a crucial role in supporting and improving industrial manufacturing processes [4,5]. Traditional value stream mapping (VSM) methods are suitable for planningbased production process reengineering. Some studies introduce the methodological contribution to integrating digital twins and VSM for SMEs. This approach is based on a simulation to improve quantitative analysis in the production process by reengineering tasks and logistics [6] and provides a framework based on the digital twin to use physical

**Citation:** Kihel, Y.E.; Kihel, A.E.; Embarki, S. Optimization of the Sustainable Distribution Supply Chain Using the Lean Value Stream Mapping 4.0 Tool: A Case Study of the Automotive Wiring Industry. *Processes* **2022**, *10*, 1671. https:// doi.org/10.3390/pr10091671

Academic Editor: Zhiwei Gao

Received: 20 July 2022 Accepted: 16 August 2022 Published: 23 August 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

product data, virtual product data, and connected data that link physical and virtual products for product design, manufacturing, and service. It is possible to design digitized views of the different actors in the chain and simulate their reactions. The digital twins involve partners, suppliers, customers, etc., and all actors in the company's supply chain.

VSM 4.0 is one of the effective tools to analyze, optimize the process, and eliminate waste [7].

The VSM 4.0 method, which is easy to implement, makes it possible to identify, with the help of a diagnostic, classic waste as well as information wastes and to design lean value flows in terms of products and, above all, of information flows [8]. Thanks to the VSM 4.0 application, it is now possible to perform a value stream analysis, to create a new value stream design based on new digital technologies [9].

Our problem involves studying, analyzing, and optimizing the efficiency and effectiveness of a logistic chain of the multinational Automotive Equipment Manufacturer EAKM located in Kenitra, which knows is in hard competition with other companies. We will first focus on the downstream part of the SC which concerns the shipping area, preparation of orders, and loading into trucks in the factory. Then, we will investigate the different stages of road and sea transport from Kenitra to Vienna according to the following route: Morocco, Spain, France, Italy until delivery to the EAVA warehouse in Austria. Following the different types of existing waste identified, we will propose modern technologies to be integrated into the logistic line as solutions for a better performance of the whole SC. The SC functions will be connected by 4.0 technologies, with a visualization of all the tasks with the VSM 4.0 tool. The results obtained are very satisfactory, particularly the collection of data, the optimization of the functions of the operators in Morocco and Vienna, automation of several workstations, tracking of products throughout the supply chain, and optimization of transport time between the two countries.

For the working methodology, we present a literature review on VSM 4.0, its usefulness in Lean Logistics, and the different modern 4.0 technologies compatible with VSM with their advantages. Next, we perform a VSM mapping of the current state and define the different tasks of the process. Finally, by analyzing the current state, we will propose improvements for establishing the future state of our VSM 4.0. The results obtained are also part of a sustainable development framework through improving the economic, social, and environmental components.

#### **2. Literature Review**

#### *2.1. Lean Production System*

In manufacturing systems, research is focused on reducing process variability, increasing productivity, and developing new processing methods to reduce costs, implement predictive models, increase quality, and adopt intelligent automation and robotics solutions by adopting lean manufacturing [10].

The Lean concept is a solution to reduce the complexity of automated production systems. One of the latest developments of the adaptive production system is Lean Automation, which allows the system to adapt to future market requirements by achieving high flexibility and short-flow information. This new theory offers the perspective of integrating the Industry 4.0 concept into a Lean production system [11].

According to Lean theory, there is a set of tools and applications through which waste is identified and eliminated or reduced. Also, a set of Industry 4.0 fundamental technologies has been identified through which losses are identified, managed, or eliminated [12].

In this research work, we are interested in the lean VSM tool and how the new technologies of Industry 4.0 can contribute to it. In addition, VSM 4.0 eliminates redundant steps in information logistics along the value chain.

In the following paragraph, we conduct a literature review on SCOPUS to further our research on this topic.

#### *2.2. Research in VSM 4.0 Published between 2016 and 2021*

We used Scopus, a scientific research platform, to determine the number of publications on VSM 4.0 between the years 2016 and 2021 (Figure 1).

**Figure 1.** Number of publications from 2016 to 2021 on VSM 4.0.

According to the results of the bibliographic research, the total number of articles remains low, showing that the VSM 4.0 is a new and very interesting topic, which researchers and industrialists are developing more and more.

#### 2.2.1. Publications of the Theme in Relation to New Technologies between 2016 and 2021

We conducted a more in-depth bibliographic study on the SCOPUS search engine only for scientific articles that were published between the years (2016–2021).

The objective of this study was to show the relationship between 4.0 technologies and the VSM tool used in the literature or in the industry. The results obtained are presented in Figure 2. We noticed that IoT technologies and Big Data are the most frequently cited. In addition, the rest of the technologies, such as cloud computing, robots, artificial intelligence, etc., remain useful for the VSM 4.0. These results can be explained by the large amount of information to manage, the physical flow of products, the number of stakeholders, and the SC.

**Figure 2.** Number of publications of 4.0 technologies used in VSM4.0.

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#### 2.2.2. Publications sur VSM Classique et VSM 4.0

Table 1 presents the research work (17 articles) on the VSM tool with the integration of new technologies for the last few years and, particularly, the benefits it can offer to logistics activities.


**Table 1.** Literature review from 2015 to 2022.


#### **Table 1.** *Cont.*

We find that the new VSM 4.0 method creates a digital and collaborative work environment for management teams and stakeholders in the Industry 4.0 era. It offers logistics production companies a huge benefit in the planning and optimization processes by digitizing the value to make improvements and more accurate decisions.

The objective of our research is to introduce digital and automatic tools to collect data, intelligent means of information processing, data storage medium, and key performance indicators (KPIs) so that the monitoring of the logistics activity and the information management system (IMS) are accurate and consistent and within the framework of sustainable development. The information collected can be visually represented in real-time to logistics managers.

In conclusion, the approach of VSM is very effective and often used in the literature for production with possible extensions to transport, quality, environment, etc. we want to use VSM as a model to support the analysis process of the downstream SC.

According to the literature review, this method is more applied to the automotive industry, especially to the procurement and production process, and very little work has begun to apply it to the downstream supply chain.

#### **3. Lean Value Stream Mapping VSM Implementation Method**

#### *3.1. Value Stream Mapping*

Value Stream Mapping was developed by engineer Taiichi Ohno at Toyota to identify and eliminate waste sources [27]. Value Stream Mapping (VSM) is a type of flowchart used to analyze, model, and propose improvements to the processes leading to the delivery of a good or service. It is one of the most frequently used formalisms in companies. Indeed, it is a key element of the Lean methodology to detect and eliminate waste. By grouping all the activities that make up the supply chain, the VSM tool aims to identify non-value-added processes that are considered wasteful. Following this teamwork, improvement solutions are developed to correct these bottlenecks to optimize the production flow [28]. The VSM tool takes into consideration physical flows, but especially information flows [29].

#### *3.2. Advantages of the Lean VSM Tool in Logistics*

According to our bibliographic study, several authors have shown that the VSM method is an essential tool in Lean Manufacturing and Supply Chains [2,28] for several reasons:


The VSM integrates three components: material flow, information flow, and scheduling. Building a VSM is often the first step in the transformation to lean. The VSM tool identifies problems and provides suggestions on how to transform the process to lean. In other words, the VSM can be used to identify where loss occurs and where value is added. It can also help a company understand what value it is actually providing to its customers [30].

#### *3.3. VSM Map Design Process*

To analyze the current process of the downstream SC, we have chosen the lean tool of VSM to map the value chain. This tool allows us to analyze all the tasks of the SC with the objective of optimizing the tasks that have a non-added value. This approach offers the possibility of federating human capital around common objectives focused on economic, social, and environmental performance. In this study, we present the development of this VSM project in 6 steps, as shown in Figure 3:

**Figure 3.** VSM design process.

#### **4. Contribution of 4.0 Technologies in Logistics**

Before approaching the case study of downstream logistics, it is fundamental to conduct a study that establishes the relationship between 4.0 technologies and logistics processes. This work is of great necessity and considered a decision support tool for the implementation of our approach

Table 2 presents a study of the most recent technologies and their impact on the different SC processes in different industries and modern logistics companies.

It is clear that there is a multitude of Industry 4.0 technologies and the disparity of their uses in the industrial world (Table 2). Each of the technologies mentioned can be used according to the needs of the company, the specificities of the sector, and the amount of investment that can be made by the companies. Negotiating the digital shift is imperative for companies today. Knowing the technological building blocks of Industry4.0 will allow decision-makers to ask themselves the right questions about their uses in accordance with the needs and priorities to be defined very early on.


**Table 2.** The different 4.0 technologies used in the industry.


Table 2, presents a study of the most recent technologies used in different industries and modern logistics companies.

We note that 4.0 technologies clearly contribute to the improvement of the supply chain and provide efficient solutions for forecasting the flow of supplies, sales, distribution, and location of products in the warehouse.

#### **5. Case Study of an International Supply Chain in the Automotive Industry**

#### *5.1. Presentation of the Study*

Our case study was carried out in a company of Automotive Equipment Manufacturers located in Morocco (EAKM) to deliver to its warehouse in Vienna (EAVA) and distribute products throughout Europe. Its official headquarters is in Austria. The group specializes in designing and realizing electrical cables for the automotive sector, whose production is done in Kenitra, Morocco. The production of electrical and electronic components is entirely intended for export and, more particularly, for the large car manufacturers in Europe.

The circuit through which the product passes is three stages and presented on Figure 4:


Our work focuses on the downstream supply chain of the distribution process that transports the finished product to the company's warehouse in Vienna, Austria.

#### **Table 2.** *Cont.*

**Figure 4.** Road and sea transport route.

#### *5.2. Analysis of the Current State*

To analyze the current state of our value stream mapping, we will proceed through three steps:


**Table 3.** The tasks of the distribution process.


The different steps of the downstream process in the company are identified and projected on the VSM map. The objective is to visualize in a clearer way the positions that require the most attention, for example time management, number of operators, cycle time, and non-value-added time (see Figure 5). Following this first mapping of the current state, the company wants to improve its competitiveness. In this framework, we will propose an improvement by introducing new technologies of industry 4.0, whose objective is to optimize this downstream supply chain. Therefore, we will first propose the most used 4.0 technologies in modern companies and the most suitable technologies for each workstation; this leads us to obtain a new future state mapping called VSM 4.0 (future map), which will receive new data and information from the whole SC, rationalizing both the management of information flows and product flows.

**Figure 5.** Mapping of the current state.

#### *5.3. Implementation of the Methodology*

In order to implement the research work, a methodology of implementation in 4.0 was implemented. It was divided into three phases:

First, according to the previous approach Figure 3, the first phase is to study and analyze the existing process in order to obtain the objectives, identify the process, and understand the industrial context of the company, then determine the sources of waste in the process and finally propose solutions.

The second phase consists in implementing 4.0 technologies in the supply chain. Study the compatibility of these technologies with each process and establish a VSM 4.0 mapping, where each process will be connected to this mapping (Future Map).

Finally, phase III corresponds to the collection and processing of data by the WMS, ERP, and intermediate communication tools and their connectivity. We present in Figure 6 below the results of the methodology implementation.

**Figure 6.** VSM 4.0 implementation methodology.

#### *5.4. Implementation of Technologies*

We have established the relationship between the 4.0 technologies and the different tasks of the downstream logistics process (see Table 4). The company has selected the technologies according to the following criteria:



**Table 4.** Assignment and adaptability of technologies to process functions.

The 4.0 technologies chosen by the company are implemented in the different functions of the logistic process. A training of the personnel took place for a mastery of these technologies to accompany this digital transformation. After six months of work the results were very satisfactory (see Table 5).

**Table 5.** Contribution of technologies for each process.



#### **Table 5.** *Cont.*

#### *5.5. Future State Mapping VSM 4.0*

Figure 7 shows the future state 4.0 mapping of the downstream supply chain. Our value stream mapping is optimized with fewer tasks. The total number of workstations within the company is reduced to 9. In summary, after implementing this new mapping along the supply chain we obtained the following improvement results by implementing VSM 4.0 within the international supply chain:


Processes 2022, 10, x FOR PEER REVIEW 15 of 21

Figure 7. Future State 4.0 Mapping. **Figure 7.** Future State 4.0 Mapping.

#### 6. Analysis of the Results **6. Analysis of the Results**

#### 6.1. Implementation of the Technologies (Future State) in the SC *6.1. Implementation of the Technologies (Future State) in the SC*

After implementing the previously proposed solutions, Table 6 presents the various improvements on the downstream part of the logistic chain from Kenitra-Morocco to Vienna-Austria. We merged the collection and grouping using stacker cranes and the verification with the edition of the file. This action allowed us to optimize the process cycle time, the information flow in the company, as well as the role of the operators. By using new 4.0 technologies, automation, and connectivity, we have managed to optimize these processes reducing time, risks, and energy consumption. After implementing the previously proposed solutions, Table 6 presents the various improvements on the downstream part of the logistic chain from Kenitra-Morocco to Vienna-Austria. We merged the collection and grouping using stacker cranes and the verification with the edition of the file. This action allowed us to optimize the process cycle time, the information flow in the company, as well as the role of the operators. By using new 4.0 technologies, automation, and connectivity, we have managed to optimize these processes reducing time, risks, and energy consumption.


Table 6. Comparison table between current state and future state 4.0 in warehouses. **Table 6.** Comparison table between current state and future state 4.0 in warehouses.

#### *6.2. SC Performance after Integration of New Technologies*

Currently, an SC's design must consider the interests of all integrated actors. Logistics is part of a "sustainable" movement, and Sustainable Development (SD) is becoming increasingly important within companies. According to this vision, companies are obliged to think about the extended economic, environmental, and social/societal performance. In this context, we present the improvement of the company's performance after the integration of new technologies.

6.2.1. Economic Performance

We have seen a strong benefit in time saving such as:


Table 7, we compare some indicators after the implementation of this new card, and we note the improvements and efficiency introduced.


**Table 7.** Gain between current state and future state 4.0.

These results are obtained thanks to the technologies introduced in this supply chain Table 6. For transportation, the value-added time and the non-value-added time is presented in Table 8.


**Table 8.** Transportation Comparison Table between Current State and Future State 4.0.

Finally, the Lead Time and the time between the order and final delivery of the product to the customer are compared.

This section may be divided by subheadings. It should provide a concise and precise description of the experimental results, their interpretation, and the experimental conclusions that can be drawn.

In order to analyze the current state of our value stream mapping, we will proceed by:


With the integration of these technologies, we witness a performance in time, distance travelled, truck fill rate, control of the distance travelled, and stop management.

The reactivity and flexibility led to improved logistics services, customer satisfaction, and increased turnover.

#### 6.2.2. Social Performance

With the introduction of the Lean VSM method combined with 4.0 technologies, automated handling, and the motivation and development of the staff through the number of trainings, the number of conferences/seminars on sustainability, and the level of effort and communication to understand all stakeholders of the company and the concept of sustainability, it has been noted for a duration of the year 2021:

A space-saving in the warehouse of 20% is due to the use of modern handling equipment such as stacker cranes. The new organization and the space-saving have significantly reduced the travel circuit in the warehouse. The use of augmented reality has facilitated the location and inventory of products. The movement of products is reduced by the AGVs and the number of staff too. All these technologies had a very positive impact on the logistics staff. We have identified three indicators to show this impact on the social environment of the company as presented in Table 9.


**Table 9.** Social indicators.

We noticed that the number of accidents and the rate of absenteeism was very low after one year. With the introduction of a preventive maintenance of the material, the number of hours of intervention on the machines was much reduced.

As a result of these changes, we noticed a climate of trust, team spirit, motivation, employee satisfaction, and a collective intelligence that developed.

6.2.3. Environmental Performance

We noticed a positive impact on the management of resources in particular:


#### **7. Discussion**

There was a gap of 5336.6 min, equivalent to three days and some hours in Lead Time. This was the result of optimization of the supply chain by modifications to the transport process and implementation of new 4.0 technologies in the warehouse of Kenitra and Vienna.

First of all, in EAKM Kenitra-Morocco, by using 4.0 technologies such as automatic handling equipment: stacker cranes, AGVs, and ATLS, we facilitated the role of the operators, and, as a result, these tasks will no longer be carried out manually but by machines and more quickly than before. This means that the number of operators in the process can be optimized, especially in the receiving area of the EAVA warehouse in Austria.

Secondly, through connectivity technologies, such as augmented reality, RFID, and Smart pack, connected to the WMS of the warehouse and the ERP of the company to follow the quantity, location, and state of the product at every moment in the warehouses of Kenitra and Vienna and the transport are tracked.

For the existing means of transport, the container was transported by a truck to Tangier, unloaded at the port, and loaded on a commercial ship. Then, in Algeciras, again, it is loaded in a truck which transports the goods to Vienna.

The proposed solution is to transport the goods and store them in a truck that makes the whole trip from EAVA to Vienna. This will avoid the costs of loading and unloading operations in both ports, which are very expensive.

Finally, at the transport level, we add a second transport staff to reduce the non-valueadded time at this level for the journey to Europe.

#### **8. Conclusions**

The objective of our study was to provide a methodology based on Value Stream Mapping 4.0 for the continuous improvement of the downstream SC distribution process.

We established a VSM map to analyze the current state, then the design of the future state with optimization of some tasks considered competitive for the country of origin and the integration of 4.0 technologies accepted by the company from the point of view of implementation time and budget. Through this work, we were able to improve economic, social, and environmental performance. With the Lean Value Stream Mapping 4.0 tool, all products and information flow in a value chain from suppliers to customers are analyzed and optimized.

The integration of 4.0 technologies makes the VSM tool capable of monitoring value streams in real time to resolve potential waste quickly. This new intelligent organization provides a fully integrated logistics environment where data is transmitted in real time between warehouses in the countries concerned and the customers. The results obtained are encouraging and have an impact on economic and social performance. The introduction of new technologies in a company requires a significant investment cost but is quickly paid back by the improvements offered.

**Author Contributions:** Conceptualization; methodology, software, formal analysis, investigation, data curation, writing—original draft preparation, Y.E.K.; writing—review and editing, A.E.K. and S.E. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We would like to thank the EAKM distribution team for allowing us to collaborate with our research team by providing us with the downstream logistics process data. We would like to thank the engineers and managers of the logistics distribution chain for the time they devoted to us, and for agreeing to implement the methodology developed within their international distribution chain.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

