**2.3 Research about the FMEA-Process implementation at First Article Inspection (FAI) for materials composites pieces**

Another study focused on some aspects of quality control at the First Inspection Article (FAI) for composite parts used in the railway sector.

An FAI is performed in a planned manner for each first piece or first set of parts made in a project. In many industrial areas, including the railway sector, in the prototyping phase of composite products, this requires strict quality control. The last step in the reproducibility of the validation process is to check that the parts made comply with the technical drawings and specifications of the requirements [22]. Quality control for a prototype, FAI is performed in a planned manner for each first part or first set of parts made in a project. Process performance must be measured by a performance indicator [23].

The FAI will include all details and subassemblies that make up the final product manufactured or ordered. All requirements must be verified by documentation and also all characteristics will be inspected and verified [24]. Approval in the first article is done to demonstrate that the manufacturing process and quality control methods of the products used are appropriate to make a product that meets customer requirements [25].

One of the most important steps in the application of product design FAI is the implementation of the method of efficient process error analysis (PFMEA) for product and process validation [26]. The method of organization and performance is the responsibility of the production department [27]. **Figure 32** shows a detail of the technical drawing of the composite part under study for FAI.

The materials used to obtain the product were [28]:


**Figure 32.** *Details from the technical drawing of the composite piece subjected to FAI study.*

Giralithe® Ditra GL 2109-10 XP is a self-extinguishing, self-extinguishing resin made of low-viscosity, low-viscosity polyester resins. It has been specially obtained for applications in public transport engines and vehicles.

NUVOPOL® Gelcoat 37-03 TGP is a specially designed, intumescent, white gelcoat polyester system, based on an isophthalic unsaturated polyester resin.

3M Scotch-WeldTM 7260 B/A Series is a two-component adhesive product that is used at room temperature. These adhesives are designed for bonding hard durable surfaces, elastic hard steel materials, aluminum or composite fibers, and other materials.

**Figure 33a** and **b** show the appearance of the final composite part used in the outer front area of the locomotive.

The analysis of product requirements in order to implement FAI for the final composite product is described in the diagram in **Figure 34** [28].

Next, **Figure 35** shows the process diagram for making the composite product.

In order to eliminate the risks of errors and defects during the development of the technological process for the obtaining of the composite part for the railway industry, it was considered absolutely necessary to apply the PFMEA-Process method.

The steps required to develop the PFMEA method were performed according to [29].

**Figure 33.** *The final piece obtained by composite materials.*

**Figure 34.**

*Logical diagram of the analysis of product requirements [27].*

**Table 7** shows the important aspects of the PFMEA analysis when making the part, respectively the operations in which the RPN value was higher than 70.

**Table 7** shows that, for each operation in which the value of the RPN index was higher than 70 (yellow and red areas), measures were proposed to improve the value of the RPN, finding that, after their application, the value of the criticality index has been greatly diminished.

In **Figure 36**, the distribution of the RPN index for each phase of the technological process is presented [28].

**Figure 35.** *Diagram of the technological process for the obtaining of the composite product.*


*Failure Analysis – Structural Health Monitoring of Structure and Infrastructure Components*

> **Table 7.** *Aspectsofthe*

*FMEA-process*

 *analysis performed*

 *for the FAI.*

#### **Figure 36.**

*The RPN index distribution for each phase of the echnological process [28].*

In **Figure 36**, the numbers in the circles represent the steps of the technological process: 1 is for the material preparation; 2 is for mold preparation; 3 is the mold treatment; 4 is materials preparation; 5 is the gel-coat applying; 6 is for rolling; 7 is labeling; 8 is for drying; 9 is the finishing; and 10 is the final inspection.

After applying the PFMEA method, the value of the RPN index was reduced below 20 due to the application of the recommended measures. Some of them are presented in **Table 7**.

In conclusion, by applying the FAI, both the product quality and the process were monitored according to customer requirements. Also, during the implementation of the FAI procedures, the risks of errors and defects occurrence were analyzed by applying the PFMEA method and technical and control procedures were developed: Process Diagram, Control Plan, Execution and Control Technology.

The quality of the product is certified by a protocol resulting from the First Article Inspection (FAI) signed between the parties

## **3. Conclusions**

Modern methods of systemic quality design are answers to new quality requirements, they must allow the analysis and elimination of potential defects from the design and implementation stage [7], so that more and more often the notion of "quality design" is encountered.

One of these methods that has become increasingly used in recent decades is the FMEA. Failure modes, effects and analysis (FMEA) is a systematic method of determining and preventing errors, defects, and risks that may occur, applicable to a process, product, or machine used in the process [30].

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. FMEA method is regarded as a basic instrument in project management, the maintenance, and the total quality and could be considered mainly a qualitative analysis.

FMEA is a systematic technique that identifies and prevents product process and system problems (defects) before they occur. It is a method that focuses on preventing problems, therefore increasing safety for improving customer satisfaction.

FMEA can be used in the following situations [31]:


By applying this method, the risk of failures in the design and manufacturing of products is reduced

On this basis, it ensures reduced costs in all stages of quality spiral: the design through a better reflection of customer requirements in quality design, supply, to avoid problems caused by improper selection of suppliers, production by preventing critical points in the service door, reducing customer complaints, etc.

The method is applied in two main variants [32]: in the product design or process development stage product and process.

FMEA design product to the design of products (components) or their redesign to prevent errors in design and implementation of future product failures is applied. Responsibility for FMEA design product implementation is the responsibility of design department.

After presenting the methodology of FMEA, the application and implementation of some proper research in this area were presented.

The studies developed on the implementation of quality methods in manufacturing processes in automotive engineering focused on the following directions:


For the FMEA-Process analysis (PFMEA), it was considered of interest to approach several studies on the application of the method for:


After applying the FMEA method, it was found that for both elements studied, after applying the necessary measures, considered after the analysis, in order to

execute the recommendations for each operation with a high RPN, it decreased to zero, which led to some finished products with "zero defects."

Another research carried out was the study of aspects on quality control at the inspection of the first article (FAI) for parts obtained from composite materials used in the railway sector. By applying FAI, both product quality and process were monitored in accordance with customer requirements.

Also, during the implementation of the FAI procedures, the risks of errors and defects were analyzed by applying the FMEA process method, and technical and control techniques were developed: Process diagram, control plan, execution, and control technology.

After applying the PFMEA method, the value of the RPN index was reduced below 20 due to the application of the recommended measures, and the product quality was confirmed by the elaboration and signing by the parties (manufacturer and beneficiary) of the protocol resulting from the inspection of the first article.

## **Acknowledgements**

The authors are grateful to the University of Craiova, Faculty of Mechanics, for advice and support. This research was funded by University of Craiova, Faculty of Mechanics, 13 A.I. Cuza Street, RO-200585, Craiova.

## **Author details**

Cristina-Ileana Pascu\*, Raluca Malciu and Ilie Dumitru Faculty of Mechanics, University of Craiova, Craiova, Romania

\*Address all correspondence to: ileana.pascu@edu.ucv.ro

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