Reliability: Refers to the probability that a group will work correctly during a certain period of time, this under the
specific optimal scenarios that may exist, some examples of these scenarios are: temperature, tension, speed or pressure condition…
reliability-engineering-martin-railingIntroduction
Since Henry Ford created the series production system with his famous Model T, most of the products that we acquire on a daily basis are created or formed in a similar way, of course we cannot say that it is the same as how Ford did in the past, since the production systems have evolved in an incredible way, they are usually of a large size with dimensions that cover kilometers, they also have a large number of collaborators who are in their care and we cannot forget the price of the facilities they use and of the equipment itself.
Like the stages of life that we humans have, the systems have a similar one, which covers different stages. It can be said that the first is the assembly and put it to work, until it reaches its optimal working regime. The second phase, normally known as the operation phase, which is the really productive one, where the system will be affected by failures or problems that reduce its production capacity, causing it to have to be stopped for some time or terminate its operation. useful life.
There must always be a maintenance (in its different stages), to avoid reducing as many as possible the failures that may arise.
We could say that the purpose of reliability engineering is to study the life time and possible failures that may occur in systems (although it can also be applied to products). Reliability engineering will make use of various tools and will be based on mathematical principles to determine why an equipment fails.
So, for obvious reasons, for many organizations it is necessary to use these tools, in order to have a better understanding of the failures of their systems, they will be able to identify some improvements for their systems in order to extend their useful life or at least decrease the consequences that these failures entail.
Key concepts
To facilitate the reading process on the topic "Reliability Engineering", some definitions that are considered important for the reader to know are cited:
Engineering.
"It is the set of scientific and technological knowledge for the innovation, invention, development and improvement of techniques and tools to satisfy the needs and solve the problems of companies and society." (Wikipedia, 2018)
Reliability.
"The ability of a product to perform its function as intended. Otherwise, reliability can also be defined as the probability that a product will perform its intended function without incident for a specified period of time and under stated conditions. ” (Ipando, 2010)
Reliability engineering.
"It focuses on technical tools and methods that together help to determine that a component, system or product works safely, providing adequate quality, under optimal conditions and under a given time." (García, 2014)
Origin of reliability engineering
The very concept of reliability, like many methodologies or tools that have to do with quality or productivity, had its beginning and apogee during World War II, the warlike conflict in which various countries of the world were immersed, since all the primary goal of the countries was to achieve a high level of reliability in all their materials and products that they used in battle, in order to reduce as much as possible the probability that these would fail.
materials
Over the years, this concept has acquired different meanings, until it is molded into what we know today, being a very important area of research for people who are dedicated to reliability engineering, having a wide variety of mathematical concepts.
Reliability
As it could be read in the key concepts, reliability can be interpreted as the trust or reliability that a production system, some process, a machine, products, among others, carry out their routine functions in a certain period of time already established. In other words, reliability refers to the stability of certain acceptable results that the elements mentioned above must have during their useful life.
In the reliability analyzes it is expected that the results of the analysis of processes, machines, systems, will be the same or even greater than the results obtained in past analyzes. If this is true, it means that the degree of reliability you have is high.
(Morales, 2017) He mentions how we can calculate the reliability of a product, system or machine can be expressed through the following mathematical formula:
? (?) =? ??
Where:
R (t) = Reliability of a product, system, machine, among others, in a set time. e = Neperian constant (e = 2.303…). t = established time.
Reliability is the probability that a failure of any kind will not happen, during the period in which the systems, equipment or processes are working, which already have a fixed goal and established level of confidence.
Reliability is a process that is becoming increasingly relevant within organizations, as technologies grow by leaps and bounds, this leads to products becoming increasingly complex, consumers are more have more sophisticated specifications to meet and the market it is very saturated. It is for all these factors that it is of utmost importance that all processes, systems and products must have high reliability, so that organizations can remain competitive and float in the market.
The data necessary to carry out the relevant reliability studies come from different places and stages of the processes, such as:
- The set life time The duration of the faults that have been taken Data on the level of wear The time of the fault that has been located within the process; among others.
Within the study of reliability, it is important to know the life cycle of the different elements that we are going to study, whether they are systems, processes, products, among others, since it will allow us to build reliability parameters so that the client is satisfied with what is being delivered
Reliability Block Diagram
The purpose of the reliability block diagram is to be able to find the% reliability of a system, where the reliability of the parts that make up said system has already been calculated.
Serial configuration
When the system has a serial configuration, all its components are considered to be critical, since all the components should work for the system to work correctly. We must bear in mind that the reliability of the system will not be greater than the reliability of the component that has the least reliability.
(Córdova, 2014) It indicates that we can calculate the reliability of the system with the following formula, it can also be defined taking as a foundation the probability of failure (F).
Rs = R1 x R2 x R3; Fs = 1- (1-F1) x (1-F2) x (1-F3).
Serial block diagram (Córdova, 2014)
Parallel configuration
When the system is in a parallel configuration, the components will have the mission of performing the same function and it will be enough if at least one of the components works so that the rest of the system does it too. It can be calculated with the following formulas, likewise, as in the previous configuration, it can be interpreted based on the probability of Failures (F).
Rs = 1 - (1-R1) x (1-R2) x (1-R3); Fs = F1 x F2 x F3.
Parallel block diagram (Córdova, 2014)
Other settings
Also within the diagrams, we can find one that is the combination of the two previously mentioned. It could be the case of finding a parallel diagram - series or a series diagram - parallel.
Bathtub bend
Within the study of reliability, something that will help us better understand all this is the idea of the curve of the bathtub. In most products, systems, devices, among others, the function of the failure rate has a shape that closely resembles that of a bathtub.
The idea of the bathtub curve is that the risk function for systems, devices, among others is developed as in the following image:
As can be seen in the graph, at the beginning of the useful life of the elements mentioned above, the weakest ones do not work properly at a relatively high rate, as a result of a phenomenon called “infant mortality”, this could be due to a bad manufacturing process. As a result of the first failures, defective products or items are removed, the risk rate will be reduced.
As can be seen on the far right of the graph, something similar happens, when the useful life of the products is ending, those that are still working tend to fail more frequently, this due to all the wear they have suffered as a result. throughout all the time that they have been working, so that the risk rate will grow.
In the part that is in the middle of the graph, a low risk level is appreciated and it remains relatively constant. This interval is normally recognized as the "functional life of the element".
Youth (Infant Mortality Zone).
The problem occurs immediately or in a very short time after it was launched, some of the probable consequences may be:
- Errors in its design. Manufacturing or assembly defects. Complicated adjustment, which is necessary to inspect the true operating conditions until we find what is the point we want.
To prevent this part of the graphic of the bathtub, when possible it will be subjected to the elements to an initial “burning” eliminating the parts that turn out to have some defect or problem. This "burning" or also known as initial filming is done by subjecting these elements to situations we could say "exaggerated", which will make the failure mechanisms rush. The elements that exceed this part are those that will be put up for sale or those that can start their real work, already in the useful life zone.
Maturity (shelf life)
Right in the middle of the graph is the maturity (what we could consider the useful life) having a more or less constant number of failures. It is the period that takes the longest time, in which the systems are studied, since it is considered that it is where they have to change before they reach the aging part and begin to generate more problems than satisfactions to the organization.
Aging
This part presents what is called "exhaustion" of the system. The number of breakdowns suffered by the system begins to increase more and more, as the components fail due to degradation of their characteristics due to the passage of time. Even with corrective maintenance and certain composures, failures will continue to increase in number, making it increasingly expensive to maintain that system.
Reliability and maintenance
The concepts of reliability and maintenance have a great similarity to each other. Below is the definition of these two concepts:
- Reliability: Refers to the probability that a group works correctly during a certain period of time, this under the specific optimal scenarios that may exist, some examples of these scenarios are: temperature, tension, speed or pressure condition. It includes all the methodologies used to ensure adequate and continuous use of facilities, products and equipment in order to avoid breakage, that is, that their reliability is increasing.
This is why both concepts are analyzed together.
Types of maintenance
Normally, 5 maintenance classes are considered, which differ from each other by the activities carried out by each one, according to (Renovetec, 2016) these are the 5 classes:
- Corrective maintenance: Includes each of the tasks predestined to correct the defects and failures that arise from different equipment and that are notified to the maintenance sector by the consumers of the same, in the case of the systems they will be when the equipment stops work in optimal conditions. Preventive maintenance: The objective of this maintenance is to maintain a certain level of service in the equipment, scheduling the mediations of its weakest points at the most opportune moments. The type of character that this maintenance has is systematic, that is, it intercedes even if the team has not indicated the existence of a problem. Predictive Maintenance:This is responsible for invariably informing and knowing the conditions, in addition to operating the facilities through the understanding of the values of fixed variables, representative of such state and operation. The identification of physical variables whose differentiation is indicative of complications that may be arising in the equipment, such as energy consumption, vibration or energy are essential to be able to apply this maintenance. This maintenance is the most technological of all since it requires advanced technical means and sometimes, important knowledge in the mathematical, physical and / or technical area. Zero Hour Maintenance (Overhaul):It is made up of tasks whose purpose is to examine the equipment at scheduled intervals either before a failure arises, or when the reliability of the equipment has decreased significantly, so it is risky to make forecasts of its productive capacity. This review is about leaving the team at Zero working hours, that is, as if all the equipment was new. The purpose of this review is to replace or repair all items subject to wear. An attempt is made to ensure a good shelf life. Maintenance In Use:This is considered as the basic maintenance of a piece of equipment, prepared by its users. It is a series of elementary works (visual inspections, data collection, cleaning and / or retightening of screws) for which a great training is not essential, with a good previous training it is enough. Maintenance In Use is the basis of the TPM (Total Productive Maintenance).
Causes for which to use reliability engineering.
One of the characteristics with the greatest importance in a process, equipment or product is the performance that it achieves over time, that is, a correct operation with optimal conditions that it must have for a given period of time. If the performance of the products is lacking or poor, it results in considerable losses to the companies due to the concept of guarantee claims. Reliability that products maintain their conditions and continue to work correctly is essential for buyers to be satisfied with the products they have purchased, as well as it is important for organizations to avoid losses in this way. On the other hand,the low reliability in the techniques and in the equipment that the companies manage implies losses in the quality of their products as well as losses due to the constant repair of equipment and the stoppage of production techniques. The products offered in the market must adequately fulfill the function for which they were created. It is often evident how certain products are disappearing due to failures or accidents, which have caused fatal consequences. Reliability engineering goes a long way in improving the reliability of each product performing each of its functions. No organization is able to survive if the main reliability problems of its services or products are not addressed, as well as its equipment and techniques.
Thesis proposal.
Improve the reliability processes of the Combustlan SA de CV gas station through Reliability Engineering.
Objective.
Reduce the failures that the pumps have to dispatch the fuel and that they receive the different types of maintenance, in order to avoid economic losses.
Thanks.
I thank my family, for giving me all the support and the drive to continue day by day, to the Technological Institute of Orizaba for opening its doors to me and allowing me to continue my studies with the Master in Administrative Engineering and Doctor Fernando Aguirre y Hernández for motivating me with their Knowledge in the Administrative Engineering Foundations seminar to carry out each of the assigned articles.
Conclusion.
As you could read in the article, reliability engineering is something that every organization (regardless of its turn) must take into account, since it is something that if practiced all the time, it will be possible to avoid economic losses, taking our equipment and systems working optimally all the time, this will ensure we have quality products and our consumers will remain loyal to us.
On the other hand, it is a field that deserves to be studied further, since it represents an important form of specialization for many people who are interested in the quality of the different elements that make up an organization.
Bibliography.
Acuña, JA (2003). Reliability Engineering. Costa Rica: Technological Publishing House of Costa Rica.
Castela, F. (June 14, 2016). Industrial web maintenance. Obtained from
Córdova, M. (April 14, 2014). Relying on Engineering. Obtained from
García, LG (November 12, 2014). Gestiopolis. Obtained from
Going. (August 10, 2010). Scribd. Obtained from
Morales, EH (November 17, 2017). Gestiopolis. Obtained from
Renovetec. (2016). Renovetec. Obtained from
Wikipedia. (April 16, 2018). Wikipedia, The Free Encyclopedia. Obtained from
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