Reliability is commonly perceived as the ability of a product or service to provide long periods of satisfactory performance without failure during use. In qualitative terms, reliability is related to the success or failure of performance, and a lack of reliability undermines the value or usefulness of a product or service.
Reliability itself is an essential performance feature. The importance of reliability as a fundamental design feature is widely recognized today by a large number of specialists. The high reliability of the components of a production system, together with a fault tolerant design, is important if the high levels of availability demanded by modern industrial processes are to be achieved.
Reliability is also vital for the success of a company or organization, especially since a good application of it leads customers to product or service loyalty. However, mismanagement of reliability can create a series of tragic events that lead the company to its final closure.
For this reason, what is known as Reliability Engineering has emerged, whose purpose is precisely to avoid and prevent problems for the company in several of its areas.
Throughout this article, the different concepts involved in this field of engineering will be studied and analyzed.
Reliability engineering
Reliability engineering can be defined as the branch of engineering that studies the physical and random characteristics of the phenomenon known as failure.
It provides the theoretical and practical tools to predict, design, test and demonstrate the reliability of parts, components and systems and ensure their requirements and optimize their safety, availability and quality levels.
Figure 1 shows how reliability engineering is applied.
Figure 1: Reliability Engineering
Reliability
Reliability is the ability of an item to perform a required function, under established conditions for a specified period of time. In other words, we will have achieved the required reliability when the "item" does what we want it to do and when we want it to do it. By saying "item" we can refer to a product, a process, a machine, an industrial plant, a system and even a person. (Sueiro, 2012)
Reliability has a direct impact on the results of the company, and must be applied not only to isolated machines or equipment, but to all the processes that make up the organization's value chain.
Reasons to design or establish products or services with reliability:
- In the near future (or today), only businesses or companies that know and are able to control the reliability of their products will remain. Complexity of products necessitates more reliable components. Customers and the public will be more reliability conscious.The industrial world is introducing reliability engineering practices, to stay ahead of the competition, all industries need reliability programs. All companies have started to advertise that their products are reliable to increase their sales. (Rivera)
Failure
It is the effect that originates when a product, component, equipment, system or process stops fulfilling the function it is expected to perform. That is, a fault arises when:
- The component or system partially or fully fails to fulfill its function There is an unacceptable difference between the expected and the observed performance.
Failures can occur due to:
- Technical or physical defects: Includes design, materials, manufacturing, construction, assembly and maintenance Operational or procedural errors: Administration and quality control, which are related to human factors. (Zapata, 2011)
goals
Reliability engineering aims to achieve the following goals:
- Apply engineering knowledge to prevent or reduce the frequency of failures Identify and correct causes of catastrophic or repetitive failures Define methods to mitigate failures if their causes have not been identified and corrected Apply techniques to estimate reliability in new designs and analyze reliability data. (O'Connor, 1991)
Reasons
The reasons why reliability engineering came about are:
- One of the most important characteristics of a product is its performance over time. There are many cases of large economic losses due to reliability problems. Complaints are common in the performance of products. Products frequently disappear due to fatal accidents. Products must adequately fulfill the function for which they were designed. No industry can survive without addressing the reliability problems of its products or services.
Benefits
- The main benefits of applying Reliability engineering within organizations at a global level are: Meeting customer expectations on the functionality and useful life of equipment Reducing the foreseeable risks inherent in the operation of equipment and health hazards. Improve Reliability and Availability of systems (reduce failure rates and decrease downtime) Improve product marketing and guarantees Increase profit through:
-Less operating / operating costs
-Lower chances of accidents
-Optimum parts replacement time
-Optimization of warehouse inventory
- Provide solutions to the needs of the industry such as:
-Identify faulty equipment that gives loss
-Make teams more lucrative
-Identify equipment readjustment and replacement
Phases
The reliability of a product or process can be estimated through a study that is carried out in four phases:
Figure 2 Phases of the reliability study
1) Definition of objectives and reliability requirement of the product or process.
This phase is executed by a multidisciplinary team in which the voice of the customer captured by marketing and the voice of the process captured by engineering intervene, in which the technological and engineering limitations of materials and machines are considered.
2) Disaggregation of the product or process into components and estimation of reliability for each of these components.
The product or process is divided into its components and these, in turn, into its parts, in order to determine at a micro level the value of the reliability of each one of them.
3) Prediction of product reliability based on the reliability of its components.
The combination of the reliabilities of all the components gives rise to the reliability value of the product or process as a whole. Macro-level reliability estimation is complicated and can cause errors.
4) Analysis of the product or process in order to determine strengths and weaknesses and take advantage of new opportunities for improvement.
Once the reliability of the product or process has been determined during its design, the failures of the product are studied during manufacturing and throughout its life, since these are excellent agents to detect weaknesses that lead to improving the performance of the products. (Acuña, 2003)
Product and process life cycle
In reliability analysis, it is important to consider the product life cycle, as it is the clearest way to establish reliability values that meet customer expectations. This cycle is defined by four stages:
Definition and conceptual design
This is a team task, where the client's requirements are studied in depth and together with the characteristics of the process and product, a conceptual design is developed that is manufacturable.
Detailed design and development
Once the conceptual design has been tested and proven adequate, the detailed design proceeds, which considers details about the required production resources and makes improvements based on the results of the tests performed on the conceptual design.
Construction, manufacturing, or both
This is the mass production of the product, where some failures are generated that must be corrected on the fly. It must be remembered that failures that occur in the laboratory are not the same as those that occur in the field, when the product is exposed to the true shelf-life environment.
Operation
The product is already in the hands of the customer and has been put to the test. A strategy should be established to collect customer complaints, which can be valuable to improve the engineering and functional characteristics of the product.
Product failure can occur at any of these stages; however, its incidence depends on the type of product or service. It is different if it is a bridge, a building, a soft drink, a machine or an electronic device, because its incidence and effects are different. (Acuña, 2003)
Process quality control
It is defined as the process of controlling the quality characteristics of manufactured products and raw materials in order to prevent defects or inconsistencies that do not allow meeting customer expectations. Its contribution to reliability is related to the prevention of defects that can originate essentially during the manufacture of the product and that become failures during the putting into use or during the useful life of the product. (Acuña, 2003)
Weibull distribution
The Weibull distribution is the most widely used distribution for modeling reliability data. This layout is easy to interpret and very versatile. In reliability analysis, this distribution can be used to answer questions such as:
What percentage of the items are expected to fail during the burnout period? For example, what percentage of the fuses are expected to fail during the 8 hour burn period?
How many warranty claims can be expected during the life phase? For example, how many warranty claims are expected to be received during the 50,000 mile life of this tire?
When is rapid wear expected to occur? For example, when should regular maintenance be scheduled to prevent engines from entering a wear phase?
The Weibull distribution can model data that are skewed to the right, skewed to the left, or symmetric. Therefore, the distribution is used to evaluate reliability in various applications, including vacuum tubes, condensers, ball bearings, relays, and material strength. The Weibull distribution can also model a risk function that is decreasing, increasing, or constant, allowing you to describe any phase of an item's life.
Samsung Galaxy Note 7 Case
One of the clearest examples of the importance of reliability engineering is the case of the Samsung company and its mobile phone Galaxy Note 7, which runs the risk of exploding or burning and in fact there are already registered cases of these events, for which the company has been in serious problems. Here is a brief review of this controversial case:
Explosion cases
To date, Samsung has confirmed 35 cases of phone fire explosions out of the 2.5 million phones sold. Samsung Electronics Co Ltd recalled all Galaxy Note 7 devices in 10 markets, including the United States.
Explosions or fires
Since September, there have been cases of explosions of the Galaxy Note
7 such as a phone that exploded in a hotel room in Australia or another that allegedly caused a car fire in the United States, a case with much media coverage, after a man in Florida claimed that his vehicle caught fire after having left a Galaxy Note 7 charging inside. The images that were released show an SUV on fire. Most recently, a 6-year-old boy from Nueva Yoyk was taken to the hospital after his Galaxy Note 7 phone caught fire while watching videos and burned his hands.
They suggest turning them off
The US Consumer Product Safety Commission has suggested that Galaxy Note 7 smartphone owners turn them off and stop using them due to the risk of the battery exploding. In addition, the agency assured users that it was already working together with the company to remove the phones, two weeks after they made their debut on the market. Following the Commission's suggestion, the company also suggested turning off the devices, but noted that there will be no new Note 7s until the Consumer Product Safety Commission completes its review "process", while owners can change Note 7s. for a different model.
Airline ban
Several airlines have banned the use of Galaxy Note 7 phones on their planes, and the US Federal Aviation Administration (FAA) asked airlines to take the step of requiring passengers not to turn on or charge their phones during flights and do not put them in checked baggage American Airlines, Delta Airlines and United Airlines joined the measure as well as the world's leading airlines such as Singapore Airlines Ltd, the Directorate General of Civil Aviation of India, as well as the European Aviation Safety Agency and airport authorities of Australia, Canada, Japan and Indonesia.
The measure is replicated in trains or buses
The directors of New Jersey Transit (NJT), the agency that groups public transportation services in the State, joined the preventive measures of not getting on trains, buses or light trains with Galaxy Note 7 phones turned on and avoiding the charging at stations.
Incident Costs
Samsung will recall the 2.5 million Galaxy Note 7 smartphones, at a cost the company estimates at up to $ 1 billion. But added to the first estimates of the South Korean company, the losses in the value of Samsung shares are added that, in just two days, Samsung Electronic lost 22,000 million of its market value. In addition, the case can seriously affect the image of the brand, while it is in the fight of fierce competition with the iPhone 7 and with the low-priced Chinese phones.
Replacement of the Galaxy Note 7
Samsung plans to update the software of the Galaxy Note 7 phones. The new version will prevent the devices from overheating but will limit battery recharge to 60%, the AP reported, citing South Korean newspaper Seoul Shinmun. (Rebolledo, 2016)
As can be seen, in this case a correct application of reliability engineering was not carried out, which had serious consequences for the company that manufactures the device, although recently it has been said that the batteries for the phones are not manufactured by the same company, the responsibility fell entirely on Samsung, since they had the obligation to avoid and prevent such failures.
The sequels still continue, customers now distrust the quality of the brand, a large percentage of them had loyalty to that company and now they have lost confidence due to the serious failure that this device presented.
The monetary losses have also hit this company, however, what will affect it the most, will be that people now go with their competitors.
As a measure to try to avoid the massive flight of customers, the company decided to make a 50% discount for people who decide to buy the next version of the phone, the Galaxy Note 8, in which they work hard to get it to the market as soon as possible. possible. However, the damage is done, the reliability engineering was not applied well and the effort of the company to try to clean up its image will be seen when the next version of the phone comes out and it can be seen if customers return to the market. brand or definitely stay with the competition.
conclusion
Reliability engineering has gained a lot of interest in recent years due to the great competition in the market, in which customers demand better product performance and better service in line with the price they pay for it, that is, customers seek that there are no failures in what they buy or consume. This has led companies to seek a way to avoid these failures and leave customers satisfied by providing better quality products to earn their loyalty and ensure income, for which they are based on reliability engineering.
References
Acuña, J. (2003). Reliability Engineering. Technological Publishing House of Costa Rica. O'Connor, P. (1991). Practical Reliability Engineering.
Rebolledo, A. (2016). The Economist. Obtained from
eleconomista.com.mx/tecnociencia/2016/09/13/7-consequences-las-explosiones- galaxy-note-7
Rivera, J. (sf). itchihuahua. Obtained from
Sueiro, G. (2012). wordpress. Retrieved from https://avdiaz.files.wordpress.com/2012/06/calidad-y- confidencebialidad.pdf
Zapata, C. (2011). unesp. Obtained from http://www.feis.unesp.br/Home/departamentos/engenhariaeletrica/lapsee/curso_2011_ zapata_1.pdf
Table of Illustrations
Figure 1 Reliability Engineering …………………………………………………………………………………………. 4
Figure 2 Phases of the reliability study ……………………………………………………………………………. 8
This Article was prepared by Ing. Josué Pacheco Ortiz, under the auspices of Master Fernando Aguirre y Hernández, from the subject Fundamentals of Administrative Engineering, from the Master's Degree in Administrative Engineering, from the National Technological Institute of Mexico, Campus Orizaba. And supported by a Conacyt grant.
Download the original file
