1. Introduction
Market demands have changed in recent decades, forcing companies to quickly adapt to new production paradigms [
1]. The growing competitiveness between companies in the same sector increased the need for companies to look for differentiating factors to act in the market. This induced the improvement of the quality and diversity of products and a reduction in the waste that usually exists throughout the production processes. Companies tried to increase as much as possible their effectiveness and efficiency [
2]. The later are pivotal factors for the permanence of any industrial company in the current market. In this context, Lean tools have shown to be a valuable aid. Initially developed in Japan to adapt automobile production to market needs after World War II, Lean methodologies were adopted in the 1970s and 1980s by the American industry, having gained particular prominence worldwide with the launch of the book, The Machine That Changed the World [
3]. Currently, Lean thinking has literally invaded both industry and service sectors, eager to eliminate waste and make companies economically healthier. One of the factors that has strongly contributed to this vast dissemination is the diversified set of tools that fall under the Lean thinking, which can be applied individually or together, depending on the specific needs of each company [
4]. From the most basic tools such as the 5S (Sort, Set in order, Shine, Standardize, Sustain), to more complex tools like VSM (Value Stream Mapping), among others, they allow for the identification and analysis of problems, enabling them to be later overcome. However, the success of its application implies that top management makes the entire structure of the company aware, and that everyone has the objective of properly applying these tools and contributing to the company’s improvement [
5]. There are many successful stories, though this success is not global. Winning stories are found through case studies in several sectors, from the health care services to the industry.
Moreover, Lean methodologies have been associated in recent decades with other equally powerful and necessary tools, such as Six Sigma and Sustainability [
6,
7,
8]. In fact, the purposes of these concepts can be perfectly coherent. The Six Sigma methodology provides a set of five steps that essentially aim to analyze a quality problem in a process and find solutions for it, implementing and creating the necessary cycle to solidify the problem’s resolution through constant monitoring [
9]. This methodology contributes to the reduction of quality problems, i.e., reduction in the generation of non-conforming products, which is in line with Lean thinking, and reducing waste. On the other hand, when Lean is associated with Sustainability, it has commonly assumed the name Lean-Green, and it also aims to reduce waste, especially that which impacts the environment, such as reducing energy consumption [
10]. Lean thinking has also been increasingly associated with ergonomics at work. In fact, there have been studies that prove the connection between a better positioning in the workstation and the performance that a worker can perform on his workstation [
11,
12]. Thus, there has been a growing interest in improving workstations in order to make the workers’ work easier, which translates into greater productivity, that is, the reduction of wasted time and greater satisfaction in performing functions. More recently, Lean thinking has also been strongly linked to the concept of Smart Manufacturing, or Industry 4.0, as this concept aims to make production as flexible as possible, which strongly reduces waste both in terms of the process and throughout the logistics involving the different stages of production [
13]. In [
14], the authors perform a systematic review of the integration of four continuous improvement tools (CI), namely Lean, Len Six Sigma (LSS), Kaizen, and Sustainability, and of frameworks of Industry 4.0, from 1989 until 2015. A general framework is then proposed to combine CI strategies and technologies supporting Industry 4.0, to be applied to a wide range of industries. Are incorporated the essential differentiators of the four CI above, namely waste elimination and process optimization from Lean, the excellence of product quality from LSS, production upgrade through CI from Kaizen, and ecofriendly products and minimization of environmental waste from Sustainability. The realization of the Internet of Things and Cyber-Physical Systems aids in connecting the real world with virtual setups, which boosts monitoring and control of manufacturing systems and product development. It is thus possible to see that extremely positive developments have been carried out on several fronts and using different methodologies, so that the effectiveness and efficiency of processes could be vastly improved, both in the industry and in the services sector. Automotive assembly lines and companies that produce components for the automotive industry are in a sector that has consistently applied Lean methodologies as well as its most diverse developments, as it is a highly competitive industry where it is necessary to be constantly thinking of reducing waste and applying the most diverse Lean tools for this purpose. Next, some examples of theoretical and practical developments related to the application of Lean methodologies in various sectors of industry and services are reviewed. Rosa et al. [
15] investigated Bowden cables production lines usually applied in automotive vehicles, with a view to increasing their efficiency, allowing these lines to meet the new levels of demand required by the market. In a first phase, they applied the VSM tool to identify the places where it was most urgent to act, then applied a PDCA (Plan-Do-Check-Act) cycle to implement the solutions identified as likely to be applied to improve processes. Through this study, it was possible to increase productivity by 41%, requiring a low investment, which had a return in 4 months of activity. The lines thus came to comply with the new demand requirements, with no need to replicate the line to match that demand. Also based on similar production lines for Bowden cables, Rosa et al. [
16] applied the SMED tool in order to minimize setup time in the production of different references for those cables, as there is a tendency to reduce the quantity of cables associated with each reference and order and there is a growing number of references to be produced. The study allowed saving around 58.3% in the weekly time consumed in setups, which was time that reverted to productive time, thus increasing production. Also, in a company that produces pipes for air conditioning systems for automobiles, Antoniolli et al. [
17] applied the standard work tool and obtained significant productivity gains, which translated into an increase of 16% in the OEE, going from 70% to 86%, thereby reaching the world reference standard established by Nakajima (85%) [
18]. Sivaraman et al. [
19] also used Lean tools, this time in conjunction with the DMAIC (Six Sigma) methodology to improve the efficiency of an assembly line of engines for motor vehicles. After identifying the problems, measuring waste, seeking and implementing solutions, and correspondingly monitoring the improvements introduced, it was possible to register an increase in the efficiency of the assembly line of 7%. In turn, Yuik and Puvanasvaran [
20] sought to develop a framework for using Lean tools, which could be applied generically in the metalworking industry. The framework was also based on a Lean tool, PDCA. The framework essentially aimed to help SME practitioners to implement Lean tools quickly and effectively, trying to take full advantage of them in terms of efficiency of the production process. Also in the metalworking sector, Pinto et al. [
21] applied some pillars of the TPM (Total Productive Maintenance) methodology in a machining sector consisting of CNC lathes and CNC milling machines, having achieved a 23% decrease in breakdowns for CNC lathes and 38% for CNC milling machines. Thus, it was possible to induce a 5% increase in the OEE of this sector of the company due to the increase in equipment availability. Using the Level Scheduling and Takt-time tools, Klašnja et al. [
22] promoted a detailed analysis of a harness production line, using those tools and developing a redefinition of the line. It was possible to obtain a better balance of the different tasks performed along the line, showing that it is perfectly possible to use Lean tools to increase the productivity of manufacturing lines. Correia et al. [
23] promoted an in-depth study of an assembly line of complex electronic products (surveillance cameras) subject to low order volumes and high model variability, with a view to increasing ergonomics and productivity. Initially applying VSM to identify all tasks and corresponding times and sequence, they then applied Lean Line Balancing (LLB), also known as Lean Line Design (LLD), which promoted a significant improvement in line efficiency through a better balance of activities on the line. It was also registered that after this phase, other Lean tools should be applied, namely Standard Work, SMED, 5S, and TPM, with a view to eliminating some of the wasted time identified in the production line. Based on the textile sector, which is normally highly pressured in terms of competitiveness and produces many components with low added value, Neves et al. [
24] carried out a multifaceted study that aimed to increase the efficiency of trimming production lines. Applying tools such as the PDCA cycle, 5S, and 5W2H, together with other tools normally linked to quality improvement such as Pareto’s Diagrams and Ishikawa’s Diagram, it was possible to reduce the time allocated to certain tasks and increase the availability of equipment, achieving a 10% increase in worker availability, which translates into very high productivity gains for the sector. On the other hand, Martins et al. [
25] used only the SMED tool to increase the efficiency of a set of three electron beam welding equipment. After a very exhaustive study of the internal and external tasks, it was possible to verify that the tasks that could be external were already external, and thus, to improve the efficiency of the process it would be necessary to make some slight modifications to the equipment, which induced a decrease of 50% in the time needed to perform the setup. In addition, the application of the SMED methodology also allowed for the identification of the causes responsible for the generation of some quality problems, eliminating them almost entirely through actions taken to reduce setup time. It was, thus, a successful work on two different fronts.
SWOT analysis has been a widely used tool in the assessment of situations intended to be improved, or in which there has already been an intervention and the aim is to verify the implemented improvements. However, having already been used in completely different situations, such as those reported below, the tool has shown its multifaceted character. In fact, Zhou et al. [
26] successfully used the SWOT analysis to develop a selection model for the suitable strategy of prefabrication implementation in rural areas, proving the versatility of the tool in decision models. Indeed, facing four different strategies with different grades of aggressivity and describing the positive and negative factors regarding the four fields of the SWOT analysis, it was possible to define and select the best strategy regarding the faced objectives. However, Rocha and Caldeira-Pires [
27] also used this tool, but to analyze how the Environmental Product Declaration promotion could be carried out. The objective is different, but the principle used to carry out the analysis is exactly the same: a brainstorming is carried out where all the strengths, weaknesses, opportunities, and threats are listed, allowing them to consider the best solution or situation among the different sets listed, or just become aware of the situation or state of a particular process or system. In this regard, it is important that all ideas are extremely objective and perfectly accepted as consensual by the group that is preparing this SWOT analysis, and the constitution of the group and the mentality that should preside over the brainstorming are very important to the final result. Cui et al. [
28] used SWOT analysis to assess which key factors are taken into account in terms of need, location, and requirements when planning to build new underground pedestrian systems. The consistent analysis of the different ideas that resulted from the respective brainstorming allowed a greater discussion to be established around what is important when such a system starts to be planned and gave rise to guidelines that will allow for assessment of when such a system is really necessary and what its requirements are. In order to eliminate ambiguities, Phadermrod et al. [
29] applied an Importance-Performance Analysis (IPA) to identify SWOT based on customer satisfaction surveys. This analysis was later applied in a case study in a higher education institutions in Thailand, revealing a high reliability of results in the assessment of the institution’s situation, thus validating the application of the IPA to SWOT analyses and drastically reducing the subjectivity that is often related to ideas resulting from brainstorming.
Some studies resorted to SWOT analysis to identify the best Lean implementation practices. In particular, Sodhi and colleagues [
30] conducted a detailed SWOT analysis and identified LSS (Lean Six Sigma) as the best waste management technique in Indian manufacturing organizations. Abu et al. [
31] performed a systematic literature review on Lean manufacturing in wood and furniture SME and used a SWOT analysis to establish an extensive list of major factors influencing the strengths, weaknesses, opportunities, and threats, helping better decision making in organizations. Abu et al. [
31] found that although industrials are familiar with Lean concepts and methodologies, their implementation in the area of wood and furniture is still low. In line with this, Tomioka et al. [
32] revised publications over a period of 10 years and applied SWOT analysis to launch main conclusions about the implementation of Lean philosophy in Brazilian manufacturing. Several internal and external factors conditioning success in this emerging industry were identified.
Even though several gaps and problems concerning Lean deployments were found in Brazilian industry, these authors concluded that Lean tools contribute to the evolution, performance improvement, and competitiveness of the sector. In a different setting, De et al. [
33] investigated the combined effect of Lean and sustainability-oriented innovation (SOI) in SMEs. The SWOT tool was used to compare inefficient SMEs with the efficient ones and notice required improvements in less successful companies. Mishra and Chakraborty [
34] applied SWOT analysis to examine several possible frameworks for companies struggling to implement a Lean philosophy. This strategic decision-making tool can be used to help companies to choose the framework that provides competitive advantage in the sector.
This work intends to provide a global view of the implementation status of Lean thinking in Portuguese companies. A SWOT analysis is performed, supported by statistically worked data. A corresponding discussion is carried out over the results, trying to contribute to a better perception of the evolution of the Lean practices implementation in Portugal. The results can be further compared with other similar studies to be carried out in other countries, allowing for a comparison between the evolution of the implementation in different countries, dissecting the main reasons for different grades of evolution. A similar but very small study, involving fewer companies, was done in 2011 [
35].
The present study was guided by two research questions:
RQ1: What is the pathway of Lean implementation in the Portuguese industry, since 2011?
RQ2: What are the main ongoing challenges and disadvantages for Portuguese companies in the dawn of Industry 4.0 implementation?
This article is divided into five sections. In the first, the theoretical contextualization that supports the development of the work is performed. In the second, the adopted methodology is explained. This is followed in
Section 3 by the results and relevant discussion. In
Section 4, the SWOT analysis and main outcomes are described. This work ends with the conclusions in which the main ideas drawn from this study are highlighted, and future work is sketched.
5. Conclusions
Lean methodology is a management philosophy focused exclusively on process efficiency. The aim is to have better, cheaper, and more agile production or services systems. This methodology contains several frameworks, and each company is responsible for deciding which one is best suited to it and for making the respective adaptations according to the company’s reality. Having a leadership committed to the implementation of Lean is one of the most important factors for its success.
In this work, we performed a SWOT analysis of the Lean methodology implementation in national and international companies operating in Portugal. A questionnaire was prepared and sent to several companies. The questions raised relate to concepts about the application of Lean, the sectors of the company involved in the study, the size of the company, difficulties and threats found, results obtained in terms of products and services, and the implementation phase, among others. A total of 119 individual responses were received from employees from 98 companies, and from different sectors of activity.
The SWOT analysis provided a basis to characterize the companies that apply Lean, in terms of turnover, size, implementation status, and opinion on results obtained, among others. The results are summarized below.
The strengths identified in this study are “Support from the company’s management”, with the highest score (89.86%) being considered the most important factor for the successful implementation of the Lean philosophy. “Efficient communication between employees” (85.96%) is the second most relevant factor, according to respondents. The item “Highly competent employees” presented a lower score of 74%. Regarding causes that intensify these internal forces, the increase in productivity and improvement in the process were the ones that stood out the most in the study. They were given the highest rating by most participants (a mode of 6). The company’s evaluation, greater flexibility, increased company profit, and improvement in the decision-making process are other factors that also scored well, with a median and mode of 5.
The main weakness indicated by the respondents in the questionnaire was the employees’ resistance to the change process, with a score of 71.11%. Workers resist changing their behavioral patterns, which can be explained by the threat of unemployment. The lack of communication between employees and the delay in implementing the process were the second and third factors with a higher score. Another weakness is the commitment of managers, with a score of 62.89%. The good relationship between top management and its employees is relevant. “Choice of Tools” is considered an item of less difficulty in the implementation of the Lean philosophy (51.78%), preceded by the “Changing implementing teams”, with a score of 52.89%. The results of the non-parametric tests highlighted differences between LE and SMEs in terms of “Employee Resistance” and “Inexperience of the methodology implementation project team”, with SMEs being more negatively affected. Another factor in which differences were observed is management support. This is more relevant in companies that already have Lean implemented. The years of Lean practice are also revealed as one of the fundamental points for obtaining significant results. Finally, a realistic work plan and budget are essential factors for success, namely in the group of companies in which Lean has been practiced for the greatest number of years.
Opportunities—with the COVID-19 pandemic, companies were forced to restructure, making the necessary adaptations to leverage their core businesses. Sales companies became more digital to facilitate online shopping, with Amazon being the most distinguished. Other companies in the production sector, namely clothing, perfume, and wine manufacturing/processing companies, among others, changed their products in order to meet market needs (gloves, masks, etc.). There was an opportunity that was quickly recognized, and companies turned it into assets. The Lean application experience allows companies to turn detected weaknesses and threats into opportunities for improvement. The deeper the Lean philosophy is in an organization, the faster solutions to the problems are found [
54].
As threats are external factors, the company has little control over them. The accumulated experience resulting from the application of Lean makes it possible to transform the detected weaknesses and threats into opportunities for improvement. The effects of threats, such as the emergence of competition, changes in norms, or other unforeseen events can be diminished, increasing strengths (internal) and decreasing weaknesses (internal). It should be noted that flexibility and speed of response in an organization is essential to better help in times of need for change and in responding to threats [
52].
With the recent economic crisis already disclosed by the European Commission, due to the COVID-19 pandemic, with a forecast of a recession of the Portuguese GDP of 9.8% in 2020, with the eurozone as a whole to fall 8.7% [
72], it would make sense to study the effects of this same crisis on the implementation of Lean. Will companies strive to enter a new era of product development with Lean? Or will this opportunity be missed? Living in the Industry 4.0 era, the companies must be focused on the total digitization of physical assets and their integration into digital ecosystems with the various suppliers in the value chain. In [
73], a survey is conducted on the challenges of Industry 4.0 in the automotive sector. The authors identify 36 challenges, grouped into four dimensions, i.e., Manufacturing Management (MM), Manufacturing Technology (MT), Manufacturing Strategy (MS), and Workforce & Organizational Management (WOM). The authors identify two pivotal dimensions that need to be considered in Industry 4.0 implementation, namely MT and WOM. Thus, the perfect moment to start applying Lean and move to Industry 4.0 is now!
According to a survey promoted by CIP (Confederation of the Portuguese Industry) and ISCTE’s (High School for Enterprises Sciences and Technologies) Marketing Future Cast Lab, about two-thirds of companies that diversified products and services in response to the pandemic will maintain the changes made in the future. The survey indicates that 19% of companies diversified their offer, especially in the industrial sector, and in 87% of these cases, they did so without recourse to public funding [
69]. This flexibility that many companies are adopting may also be an indicator of the implementation of Lean Management.
The approach followed in the study may encourage Portuguese Industry practitioners who still have issues regarding the implementation of Lean or any other continuous improvement tool into their company, to be willing to take a step forward. This study also reviews the importance of the implementation of Industry 4.0 and how the continuous improvement methodologies, IoT, and CPS are crucial for a successful execution. The practitioners must to perform a SWOT analysis for their company and plan their steps towards continuous improvement tools and Industry 4.0 integrations according to their companies’ prioritized weaknesses and threats. Thus, the current study has practical relevance.
From an academic point of view, the methodology used in the current study may provide new insights to future researchers on how to design studies in applications of continuous improvements and Industry 4.0 adoption from other perspectives.
The main limitation is to be able to have a significant sample to study. The companies are somewhat reluctant to reply to questionnaires from academia. This was frustrating and proved fruitless. The next step was to try to select the target audience using the social network of 224 professionals and companies, LinkedIn. Here, we received some replies, but in a total of 1045 messages and emails sent, we only received 119 responses (11.4%). This was a big limitation and was time consuming. In our opinion, though there have been substantial improvements, the need for a tighter relationship between academia and companies is imperative.
Future research will consider assessing the reasons associated with the implementation of Lean in certain departments of the companies, thereby belittling others, shown empirically to be adequate for it. The performed analysis reveals that Lean is applied only in certain sectors, which irretrievably entails the loss of its potential as a whole. Other future research questions may consider the characterization of the implementation of Industry 4.0 in Portugal.