FMEA analysis: example and application

Periodically, defects occur in the development and manufacture of various equipment. What's the result? The manufacturer incurs significant losses associated with additional tests, inspections and project changes. However, this is not an uncontrolled process. Assess possible threats and vulnerabilities, and analyze potential defects that may interfere with the operation of the equipment, using the FMEA analysis.

This method of analysis was first used in the USA in 1949. Then it was used exclusively in the military industry when designing new weapons. However, already in the 70's the ideas of FMEA were in sight of large corporations. One of the first technology introduced by Ford (at that time - the largest car manufacturer).

Nowadays FMEA-analysis is used by almost all machine-building enterprises. The main principles of risk management and analysis of the causes of failures are described in GOST R 51901.12-2007.

Definition and essence of the method

FMEA is an abbreviation for Failure Mode and Effect Analysis. This is a technology for analyzing the varieties and consequences of possible failures (defects, due to which the object loses the ability to perform its functions). What is good about this method? It gives the enterprise the opportunity to foresee possible problems and problems at the design stage. During the analysis, the manufacturer receives the following information:

• List of potential defects and malfunctions;
• Analysis of the causes of their occurrence, severity and consequences;
• Recommendations on risk reduction in order of priority;
• General assessment of the safety and reliability of products and the system as a whole.

Data obtained as a result of the analysis are documented. All detected and studied failures are classified according to the degree of criticality, ease of detection, maintainability and frequency of occurrence. The main task is to identify problems before they arise and begin to influence the clients of the company.

Scope of FMEA analysis

This method of research is actively used in almost all technical sectors, such as:

• Car and shipbuilding;
• Aviation and space industry;
• Chemical and oil refining;
• building;
• Manufacturing of industrial equipment and mechanisms.

In recent years, this method of assessing risks is increasingly being used in the non-productive sphere - for example, in management and marketing.

FMEA can be conducted at all stages of the product life cycle. However, most often the analysis is carried out at the stage of product development and modification, as well as when using existing structures in a new environment.

Kinds

With the help of FMEA technology, not only various mechanisms and devices are being studied, but also the processes of company management, production and operation of products. In each case, the method has its own specific features. The object of analysis can be:

• Technical systems;
• Designs and products;
• Processes of production, assembly, installation and maintenance of products.

When examining the mechanisms determine the risk of non-compliance with standards, the occurrence of malfunctions in the process of work, as well as breakdowns and a reduction in service life. This takes into account the properties of materials, the geometry of the structure, its characteristics, interfaces with other systems.

FMEA-analysis of the process allows to detect inconsistencies that affect the quality and safety of products. Also, customer satisfaction and environmental risks are taken into account. Here, problems can arise from the person (in particular, employees of the enterprise), production technology, raw materials and equipment used, measuring systems, and environmental impact.

The study uses different approaches:

• "From top to bottom" (from large systems to small details and elements);
• "From the bottom up" (from individual products and their parts to the production system).

The choice depends on the purpose of the analysis. It can be part of a comprehensive study in addition to other methods or used as an independent tool.

Stages of holding

Regardless of specific tasks, the FMEA analysis of the causes and consequences of failures is carried out using a universal algorithm. Let's consider this process in more detail.

Training of the expert group

First of all, you need to decide who will conduct the research. Teamwork is one of the key principles of FMEA. Only this format ensures the quality and objectivity of the examination, and also creates space for non-standard ideas. As a rule, the team consists of 5-9 people. It includes:

• Project Manager;
• Engineer-technologist, performing the development of the technological process;
• The engineer-designer;
• Representative of the production or quality control service;
• Employee of the department of work with consumers.

If necessary, qualified experts from outside organizations can be involved in the analysis of structures and processes. Discussion of possible problems and ways to solve them takes place on a series of meetings lasting up to 1.5 hours. They can be conducted in full or in part (if the presence of certain experts is not needed to solve current issues).

Study of the project

To conduct FMEA analysis, it is necessary to clearly identify the object of research and its boundaries. If we are talking about the technological process, we should indicate the initial and final events. For equipment and structures everything is easier - you can consider them as integrated systems or focus on specific mechanisms and elements. Nonconformities can be considered taking into account the needs of the consumer, the stage of the product's life cycle, the geography of use, and so on.

At this stage, the members of the expert group should receive a detailed description of the object, its functions and principles of operation. Explanations should be accessible and understandable to all team members. Usually presentations are held at the first session, experts study the instructions for the manufacture and operation of structures, planned parameters, regulatory documentation, drawings.

# 3: Compiling a list of potential defects

After the theoretical part, the team proceeds to assess possible failures. A complete list of all possible inconsistencies and defects that may arise at the facility is compiled. They can be associated with the failure of individual elements or their improper functioning (insufficient power, inaccuracy, low productivity). When analyzing processes, it is necessary to list specific technological operations, in the performance of which there is a risk of errors - for example, failure to perform or improperly performing.

Description of causes and consequences

The next step is an in-depth analysis of such situations. The main task is to understand what can lead to the occurrence of those or other errors, as well as how the detected defects can affect workers, consumers and the company as a whole.

To determine the probable causes of defects, the team studies the descriptions of operations, approved requirements for their implementation, as well as statistical reports. In the FMEA analysis protocol, it is also possible to identify the risk factors that an enterprise can correct.

At the same time, the team is considering what can be done to exclude the possibility of defects, offers methods of control and the optimal frequency of inspections.

Expert assessments

What's next? Participants in the FMEA team begin to analyze each rejection by three main criteria:

1. S - Severity. Determines how severe the consequences of this defect will be to the consumer. It is estimated on a 10-point scale (1 - virtually unaffected, 10 - catastrophic, in which the manufacturer or supplier may suffer a criminal penalty).
2. O - Occurrence. Shows how often a certain violation occurs and whether the situation can repeat (1 - extremely unlikely, 10 - failure is observed in more than 10% of cases).
3. D - Detection. The parameter for assessing the methods of control: will they help in a timely manner to identify the discrepancy (1 - almost guaranteed to detect, 10 - hidden defect, which can not be identified before the consequences).

Based on these estimates, the priority number of risks (PCRs) for each type of failure is determined. This is a generalized indicator that allows you to find out which breakdowns and violations are the most threatening for the firm and its customers. Calculated by the formula:

PCR = S × O × D

The higher the PCR - the more dangerous the violation and the more destructive its consequences. First of all, it is necessary to eliminate or reduce the risk of defects and malfunctions, for which this value exceeds 100-125. From 40 to 100 points, violations with an average level of threat are accumulated, and a PCR of less than 40 indicates that the failure is insignificant, occurs rarely and can be detected without problems.

Development of proposals and recommendations

After assessing the deviations and their consequences, the FMEA working group determines the priority areas of work. The primary task is to draw up a plan of corrective actions for bottlenecks - the elements and operations with the highest HR indicators. To reduce the level of threat, it is necessary to influence one or several parameters:

• Eliminate the original cause of the failure by modifying the design or process (score O);
• Prevent the appearance of a defect with the help of statistical regulation methods (O score);
• Mitigate negative consequences for customers and customers - for example, reduce prices for defective products (S rating);
• Implement new tools for the timely detection of malfunctions and subsequent repairs (score D).

In order for the enterprise to immediately proceed with the implementation of the recommendations, the FMEA team simultaneously develops a plan for their implementation, indicating the sequence and timing of each type of work. The same document contains information about the executors and those responsible for corrective actions, sources of funding.

Summarizing

The final stage is the preparation of a report for the company's managers. What sections should it contain?

1. Review and detailed notes on the progress of the study.
2. Potential causes of defects in the manufacture / operation of equipment and the performance of technological operations.
3. A list of likely consequences for employees and consumers - separately for each violation.
4. Assessment of the level of risk (how dangerous are possible violations, which of them can lead to serious consequences).
5. List of recommendations for the maintenance department, planners and specialists in the field of planning.
6. Schedule and reports on the implementation of corrective actions based on the results of the analysis.
7. A list of potential threats and consequences that could be eliminated by changing the project.

To the report, all tables, graphs and diagrams that serve to visualize information about the main problems are attached. Also, the working group should provide used schemes for assessing inconsistencies in importance, frequency and probability of detection with a detailed interpretation of the scale (which means a certain number of points).

How to fill in the FMEA protocol?

During the study, all data should be recorded in a special document. This is the "Protocol for the Analysis of the Causes and Consequences of FMEA". It is a universal table, where all information about possible defects is entered. This form is suitable for the study of any systems, objects and processes in any industry.

The first part is filled on the basis of personal observations of team members, study of enterprise statistics, work instructions and other documentation. The main task is to understand what can hinder the operation of the mechanism or the performance of a task. At the meetings, the working group should assess the consequences of these violations, answer how dangerous they are to workers and consumers, and what is the probability that the defect will be detected at the production stage.

Analysis of potential risks
Element / Process	Possible defect / Problems in implementation	Possible causes	Consequences of potential non-compliance	S	O	D	PCR

The second part of the protocol describes options for preventing and eliminating inconsistencies, a list of activities developed by the FMEA team. A separate graph is provided for assigning those responsible for the implementation of certain tasks, and after making adjustments to the design or organization of the business process, the manager indicates in the protocol a list of completed work. The final step is the re-rating, taking into account all the changes. Comparing the initial and final indicators, we can conclude on the effectiveness of the chosen strategy.

results
Correction methods	FULL NAME. Performer	Conducted events	нов S new	нов O new	нов D new	нов PCR is new

A separate protocol is created for each object. At the very top is the title of the document - "Analysis of types and consequences of potential defects". Below is the model of the equipment or the name of the process, the dates of the previous and next (scheduled) inspections, the current date, as well as the signatures of all participants in the working group and its leader.

Example FMEA-analysis ("Tulinovsky Instrument-Making Plant")

Consider how the process of assessing potential risks on the experience of a large Russian industrial company is taking place. At one time, the management of the Tulinovsky Instrument-Making Plant (JSC TVES) was faced with the problem of calibrating electronic scales. The enterprise produced a large percentage of incorrectly operating equipment, which the technical control department had to send back.

After studying the sequence of actions and the requirements for the calibration procedure, the FMEA team identified four subprocesses that influenced the quality and accuracy of the calibration most strongly.

• Moving and installing the device on the table;
• Check position by level (the balance must be 100% horizontal);
• Placement of cargo in the reference points of the platform;
• Recording of frequency signals.

What types of failures and malfunctions were recorded during these operations? The working group identified the main risks, analyzed the causes of their occurrence and possible consequences. Based on expert assessments , PCR indicators were calculated, which made it possible to identify the main problems - the lack of clear control over the performance of works and the state of equipment (stand, weights).

Stage	Failure scenario	Causes	Effects	S	O	D	PCR
Moving and installation of scales on the stand.	The risk of falling scales due to the large weight of the structure.	There is no specialized transport.	Damage or damage to the device.	8	2	1	16
Checking the horizontal position by the level (the device should stand absolutely straight).	Incorrect calibration.	The table top was not level-adjusted.	OTK returns the marriage because of metrological inconsistencies.	6th	3	1	18
		Employees do not follow working instructions.		6th	4	3	72
Arrangement of cargo in the reference points of the platform.	Use of goods of inappropriate size.	Maintenance of old, worn out weights.	OTK returns the marriage because of metrological inconsistencies.	9	2	3	54
		Lack of control over the alignment process.		6th	7th	7th	252
	The mechanism or the sensors of the stand went out of order.	The combs of the movable skeleton are skewed.	From constant friction, weights quickly wear out.	6th	2	8	96
		The cable broke.	Suspension of production.	10	1	1	10
		The motor-reducer has failed.		2	1	1	2
		The schedule of scheduled inspections and repairs is not observed.		6th	1	2	12
Registration of the frequency signals of the sensor. Programming.	Loss of data that was recorded in the storage device.	Interruptions with electricity.	You need to re-calibrate.	4	2	3	24

To eliminate the risk factors, recommendations were developed for additional training of employees, modification of the table top and purchase of a special roller container for the transport of scales. The purchase of an uninterruptible power supply unit solved the problem with data loss. And in order to prevent problems with graduation in the future, the working group proposed new maintenance schedules and routine calibration of weights - checks were started more often, so that damage and failures can be detected much earlier.