**1.1 Method definition**

Worldwide, due to customer expectations coupled with the continuing increase in the complexity of products, declining design and launch periods have necessitated systematic quality planning [1]. In the last decade, quality control and improvement have become a priority in the development strategy of companies in all fields: industry, distribution, transport companies, health, government agencies, financial organizations, etc. Achieving and maintaining a high level of quality of products or services offer a

competitive advantage that allows a company to dominate its competitors in the field in which it operates. Thus, a company can dominate its competitors by continuously improving processes and applying quality control [2]. The application of quality control at all stages of product process fabrication is considered a zero priority in the automotive field [3]. The premise of traditional quality assurance, based on the detection and elimination of defective products, is no longer relevant, the argument being extremely simple and intuitive: defects that can be avoided before launching the product do not need to be corrected later [4]. Modern methods of systemic quality design are the answer to new quality requirements. They must allow the analysis and elimination of potential defects from the design and implementation stage [5], so that more and more often the notion of "quality design" is encountered [6]. One of these methods that has become increasingly used in recent decades is the failure modes, effects, and analysis (FMEA) [7, 8].

One of the most widely used methods in the field of quality engineering is failure modes, effects, and analysis (FMEA), with applicability from the manufacturing design stage to the prototyping and zero series production stage [9].

The FMEA is a systematic method of determining and preventing errors, defects and risks that may occur, applicable to a process, product or equipment used in the process. This method consists of detecting possible defects, inventorying the causes that could produce these defects, the effects of defects on users, in order to plan the necessary measures to prevent their occurrence [10]. The English name of the method has a correspondent both in Romanian and in French, where it is called L'Analise des Modes de Defaillance, de leur Effet et de leur Criticite (AMDEC), or in German DAMUK [11]. This method consists of detecting possible defects, inventorying the causes that could cause these failures, demerits effects on users, in order to plan the necessary measures to prevent their occurrence.

The method was originally developed by the US military, as evidenced by the 1949 MIL-P-1829 military procedure entitled "Procedures for Failure, Effects and Critical Analysis" applicable to projects aimed at ensuring the maximum availability of strategic military equipment [12, 13].

The first notable applications of AMDEC techniques are related to NASA (1960s), and later, in the 1990s, by the top three US automakers: GM, Ford, and Chrysler by including them in the prescriptions of the QS 9000 quality standard [14], **Figure 1**.

**Figure 1.** *Time evolution of the FMEA workability.*

From **Figure 1** it can be seen that since the 1970s, the FMEA method has been used in the aerospace and nuclear industry. Since 1977, the American company Ford has been widely applying the FMEA method for solving car projects, and since 1986, with the launch of 6Sigma (6σ) technique, the method has become one of the basic tools used in the US automotive industry [14].

According to ref. [15], the French claim the discovery of this method in 1995, by applying a previous AMDEC method to shorten the production time of the prototypes for the mirage fight planes.

In 1980, Renault adopted the AMDEC method to make the Clio car, which became the first feasible project obtained by applying the method to both the process and the assembly, and since 1984, the French car manufacturer has adapted and improved the method using various other names: AMDEC CONNECTIQUE, DELTA 2, etc.

The correct use of the method allows the analysis and minimization of potential risks. By applying it, all types of defects and/or potential defects in terms of causation and effects are predicted.

Once the appropriate and correct actions have been implemented, the causes of the defects can be hampered or even avoided. The FMEA is considered to be an effective tool for quality assurance prevention.

#### **1.2 The purpose and objectives of FMEA**

The purpose of the FMEA is to ensure the development of high-quality products from the design and prototyping phases, before the transition to series production.

The FMEA provides the necessary preconditions for early detection of quality problems and the prevention of their occurrence through appropriate measures.

This makes it possible to meet product quality requirements and, at the same time, reduce the costs of errors and the consequences of errors. The objectives of the FMEA are shown in **Figure 2**.

Fault analysis and effects analysis (FMEA) is a systemic analysis of potential failures of a product, process, or machine used during the process, with the goal of developing an action plan to prevent their occurrence and to improve the quality of the products, work processes, and production environments.

**Figure 2.** *FMEA objectives.*

#### **Figure 3.**

*The relationship between the origin of defects and their detection during the manufacturing cycle of a product.*

We start from the elements to determine the triplet Cause – Mode – Effect. **Figure 3** shows the relationship between the origin of the defects occurring and their detection during the manufacturing process of a product [16].

It is mentioned that the FMEA method highlights possible risks, but does not solve the problem. However, the correct approach of the FMEA can result in "zero defects" but not "zero errors."

#### **1.3 FMEA types**

There are two main types of FMEA [17]: product design, DFMEA, and process development, PFMEA, **Figure 4**.

**Figure 5.** *DFMEA and PFMEA.*

Accordingly to the AIAG, VDA manuals [18, 19], in addition to the two types of FMEA listed above (DFMEA and PFMEA), explained in **Figure 5**, the following are also known and used:


However, the FMEA method must be performed whenever errors or malfunctions may occur that could cause potential harm to the user (customer) for whom the product is intended.

The scope of the FMEA method is wide and diverse. This method can be implemented not only in industry but also in the field of services.

The FMEA is aimed at [13, 18]:


The product-design FMEA is applied immediately after the elaboration of the constructive design documentation (design) in order to follow and analyze the products from the conception and design stage.

The product-process FMEA is performed after the preparation of the technological documentation of the process necessary to make the product. It also allows the validation of the technological process of making a product in accordance with the desired quality and efficiency expectations.

FMEA machine/work equipment is executed after the system of machines, machines, and technological equipment is established. Based on that, the technological process consists of the analysis of the means of production aiming to reduce the number of scrap, failure rate and increase availability and reliability of the product. The development of the FMEA lies in the inventory of the way of detecting errors, component problems, analyzing the causes of occurrence, and evaluating their effects on the set of functions of the system.
