The significant importance of product reliability
In the grand landscape of total quality management, product reliability occupies a crucial position. It is like a solid cornerstone, supporting the product's foothold and development in the market. A truly reliable product is like a loyal partner, capable of steadfastly performing the functions assigned by the design throughout its entire service life. Reliability is no ordinary attribute; it is a unique quality characteristic that profoundly reflects the core demands of today's consumers for products.
In essence, reliability is a comprehensive technology. When considering it, one cannot be isolated and one-sided, but needs to make a comprehensive trade - off among multiple aspects. Cost - performance is a factor that cannot be ignored. Enterprises need to reasonably control costs while ensuring product reliability to maximize benefits. Customers' requirements are the compass. Enterprises must accurately grasp customers' expectations for product reliability and conduct product R & D guided by these expectations. At the same time, the company's own level is also an important reference. It is necessary to determine the product reliability based on the actual situation such as the company's own technical strength and production capacity. After determining the reliability goals and plans, it is also necessary to evaluate the plans through rigorous tests, just like adding a precise ruler to the product quality to ensure that the products can meet customers' needs.
As a key performance of products, product reliability has a unique way of measurement. Simply put, it measures the ability of a product or equipment to work continuously in terms of probability. Its clear - cut definition is: the ability to complete the required functions within a specified period and under specified conditions. The corresponding reliability is the probability that a unit product continuously completes the required functions within the specified period and under the specified conditions. Product reliability contains four important elements, namely probability, performance, time, and conditions. These four elements are interrelated and mutually influential, jointly forming a complete system of product reliability.
The development history of product reliability requirements
To gain a deep understanding of the reliability activities in total quality management, it is crucial to recognize the four basic stages in the development of modern product reliability.
Product reliability prediction and demonstration stage
Decades ago, the development of product reliability took its first step - predicting and demonstrating product reliability. The core goal of this stage was to predict the reliability of products and demonstrate whether they could meet the expected standards. Determining the failure rate of components became one of the key technologies at that time, just like finding a guiding lighthouse in the vast ocean. Meanwhile, mathematical and statistical models began to emerge in product reliability control, providing scientific methods and tools for the prediction and demonstration of product reliability.
The evaluation stage of product reliability
When the design, manufacturing, and use of products become complex, or when there are high requirements for the long - term reliable and fault - free operation of products, evaluating product reliability becomes inevitable. Thus, the development of product reliability has entered a new stage. In the production process, a series of important reliability technologies have emerged.In terms of design, technologies such as design margin, derating, and redundant reserve are like layers of protective clothing for products, which improve product reliability. Environmental stress control technology ensures that products can operate stably in various complex environments. Technologies such as fault model and its effects and criticality analysis, and physical research on failures help enterprises understand potential product failures in depth and prepare countermeasures in advance. Ergonomic design and packaging and transportation design further enhance product reliability from the perspectives of user experience and product protection.In terms of manufacturing, multiple areas of incoming material control and product control provide a solid guarantee for ensuring product reliability.
Determination and implementation of the reliability stage
With the continuous emergence of a series of reliability technologies, the development of product reliability has entered the third important stage - determining and achieving reliability. In this stage, it is necessary to effectively coordinate all activities aimed at determining and achieving reliability with the ongoing maintenance management activities. The so - called reliability "planning" is actually an organic integration of a series of reliability work and its implementation requirements. It is like a precise map, guiding enterprises to steadily move towards the goal of product reliability.
Implementation stage of mathematical statistics technology and reliability work
The development of product reliability involves the full, effective, and economical utilization and implementation of mathematical statistics techniques and reliability work. This is not the end of reliability work but an important part of the company-wide quality program. These reliability activities are key links in an enterprise's modern quality system and can ensure that the enterprise fully meets users' quality requirements.
How to formulate a product reliability plan
The control of product reliability is a systematic project that requires comprehensive consideration of multiple aspects, including customer requirements, reliability costs, reliability measurement, and reliability management activities. These factors interact with each other and jointly influence the formulation of product reliability plans.
Customers' needs
Like all quality characteristics, the requirements for product reliability are ultimately determined by the customer's usage conditions. Product reliability needs to reach a level that can not only meet customer needs but also be economically reasonable. If the reliability level is set too low, the product may malfunction frequently, resulting in excessive repair and maintenance costs and situations where the product cannot be used normally, thus increasing the customer's total usage cost. Conversely, if the reliability level is set too high, the requirements for parts and other components will increase accordingly, and the product price will also rise, which will also make the customer spend too much in total. Therefore, enterprises need to accurately grasp the customer's needs and find the optimal balance point for product reliability.
Reliability cost control
To correctly determine the reliability level of a product, in addition to considering customer needs, attention also needs to be paid to the availability of the product or service. The optimal reliability value of the product determined by the total cost enables both the manufacturer and the purchaser to obtain the best reliability. The purchaser hopes to obtain a product with the required reliability without the manufacturer having to pay excessive costs. In this case, subdividing the quality cost by item helps the enterprise to eliminate unreasonable cost items and clarify the real focus. Regarding the reliability cost, the following aspects need to be considered for control: To ensure that the product meets the required reliability, some reliability - related costs will be incurred, and these costs are part of the prevention and appraisal costs. The enterprise needs to balance these costs with the failure costs to achieve a specific product reliability. At the same time, it is necessary to optimize the total quality cost to meet the company's quality goals, including other reliability factors.
Measurement of reliability
In statistical research, it is found that a variety of reliability analysis methods can be used to identify the relationship pattern between the failure of products and components and time during the life cycle. In terms of reliability prediction, when components cannot be economically or practically repaired, they are usually regarded as prediction items. General products have a common life pattern, including the early failure period, the normal operation period, and the wear - out period. By judging the different periods that a product is in, the magnitude of the failure rate can be predicted, and then the reliability of the product can be predicted.
The measurement of reliability usually considers the following aspects: mean time between failures, operating time before wear-out, mean time between maintenance, mean time between repairs, mean time to repair, etc. The longer the mean time between failures and the mean time between maintenance are, the higher the reliability of the product is.
Reliability management activities
In the total quality management program, the activities related to product failure rate, namely the determination and control of elements such as probability, time, performance, and conditions, are highly consistent with the activities of the total quality management program and are important components of the four tasks of total quality management. The control and management activities of reliability run through the entire process of product planning, design, trial production, production, and use, and are continuous activities throughout the entire service life cycle of the product. Only when the three aspects of design, production, and use cooperate closely and continuously improve the reliability indicators of products can good economic benefits be achieved.
Develop reliability requirements
The initial work of the new design control includes setting reliability targets suitable for the product requirements. The cost of increasing reliability needs to be balanced against the relevant costs when it is not increased. Selecting reliability standards is a practical issue rather than a purely theoretical discussion. When choosing the standards, the current state of technology should be fully considered, and the cost required to push the technology beyond the current limits should be understood, so as to select the standards within the economic affordability.
Before achieving the reliability specified in detail, further technological progress may be required. To promote technological progress, the greatest efforts should be made in the most critical areas. Carefully analyzing the recommended products can identify the components with the highest failure rates, providing directions for further research and development.
Develop a reliability plan
The solutions for achieving product reliability requirements cover multiple aspects: determining the product technical specifications of equipment systems, components, and structures; clarifying the process specifications for manufacturing products; adopting reliability assurance technologies; formulating packaging and transportation specifications for product protection; selecting appropriate transportation methods to deliver products to customers; and ensuring the maintenance and repair functions to keep the product functioning as designed.
The idea of formulating the plan is to first confirm the average working time before failure through tests, and then set different reliability targets for different products. Increasing reliability will inevitably increase costs. This part of the cost is part of the preventive cost and appraisal cost, and the overall budget and balance of costs need to be considered. By determining the reliability standards for costs and conducting cost budget analysis, both the reliability and quality of products can be ensured, and product costs can be controlled, so as to meet customer needs with the optimal economic strategy and enhance the competitiveness and reputation of the enterprise.
The evaluation of reliability schemes needs to be carried out through tests. Whether it is the reliability scheme for products, manufacturing processes or packaging designs, tests should be conducted at appropriate stages of the planning. The initial design proposals can be checked through tests on mock - up boards (models), and the proposed manufacturing processes can be verified through trial production and small - batch trial production. To obtain a large amount of information from reliability tests, it is usually necessary to let the equipment run until failure. Since such tests are destructive and costly, accelerated tests are often used, which are carried out under increased loads and environmental stresses and ended before failure. When using accelerated tests, it is necessary to combine them with on - site actual operation experience. Some companies adopt the general life test method for new large - capacity products, including design maturity tests, process maturity tests and life tests. The purpose of the design maturity test is to discover and correct design problems and demonstrate whether the design meets the reliability requirements of the product. If it does not meet the requirements, the design needs to be improved during the test until the specified requirements are met.
II. Product testing helps improve reliability
Process maturity test: Identify the inconsistencies between design and production
The process maturity test plays a crucial role in the product R & D and production process. Its core objective is to accurately measure the early failure situation, and then discover and correct any inconsistencies between the design and the product production process. At the same time, through a series of test work, determine the amount of test work required to achieve the specified operational reliability.
When the first product starts to operate (pre-burn) within a given period, it's like embarking on a meticulous observation journey. We need to closely monitor its performance, not overlooking any subtle changes. Because during the early operation of the product, the failure rate may change dynamically. By continuously monitoring the performance, we can capture the trend of the decreasing failure rate, so as to conduct in - depth analysis of various potential factors leading to early failures. This may involve multiple aspects such as the rationality of the design, the quality of raw materials, and the stability of the production process. For example, an unreasonable parameter setting in the design may cause the product to bear excessive pressure during the initial operation, thus accelerating the failure; a deviation in a certain link of the production process may also affect the overall performance of the product. Through the process maturity test, we can identify these problems and provide a strong basis for subsequent improvements.
Life test: Eliminate potential failure mechanisms
The main task of the life test is to determine the wear-out failure distribution of components, so as to eliminate those failure mechanisms that may cause the expected life to drop below the acceptable point. We select several samples for testing and record their failure times. Through the analysis of these failure times, we can determine the mean time between failures (MTBF) and distribution of each observed failure model.
This is like when we want to understand the lifespan pattern of a group of people. We select a part of them for long-term observation and record their lifespan situations. Through statistical analysis of these data, we can roughly understand the lifespan distribution characteristics of this group. In product lifespan testing, by studying the failure times of samples, we can gain in-depth understanding of the failure probabilities and modes of products at different stages. Lifespan testing must ensure that the wear and tear of products exceeds the expected minimum lifespan cycle. Only in this way can we guarantee that products can meet the basic needs of users in the actual use process and avoid causing inconvenience and losses to users due to premature failure.
Through various testing methods such as process maturity tests and life tests, we can gradually identify the key factors that affect and control product reliability during the measurement process. Once these factors are clearly identified, we can take targeted measures to maintain the product's reliability at an acceptable level. Without such control, it is difficult to guarantee product quality, which may lead to the product losing its competitiveness in the market and, in turn, losing the main factor of product profitability. For consumers, product reliability is one of the important considerations when choosing a product. If a product often malfunctions, consumers will lose confidence in it and switch to other more reliable products, and the enterprise's market share and profits will decline accordingly.
III. Sustainable growth and control
Sustainable growth: Adapting to product and process changes
When a newly designed product is first put into production, we must fully consider a series of factors that vary with the complexity of the product and the process, as well as the experience and training level of the employees. An increase in the complexity of the product and the process means that there may be more uncertainties and potential problems in the production process. Moreover, different levels of employees' experience and training will also have an impact on the production quality of the product.
Within a certain period of time, the factory needs to continuously improve the proficiency required to achieve and maintain the reliability target level. This is like a novice driver. When first starting to drive, they may be in a panic and prone to various minor problems. However, as driving experience accumulates, their driving skills will become more and more proficient, and they will be able to better handle various road conditions. The same goes for the factory. As production progresses, employees will gradually become familiar with the products and processes, discover and solve problems that arise during the production process, thereby improving production reliability. Accurately predicting this reliability growth period is a basic activity in the reliability planning of factories and companies. Through the analysis of products and processes, combined with employees' training plans and experience accumulation, we can roughly estimate the time and stages required for reliability growth. This helps enterprises reasonably arrange production plans and make preparations for resource allocation and risk response in advance.
Reliability control: Comprehensive management ensures quality
The next important activity in reliability planning is continuous control. The product control work in total quality management covers all aspects that affect product reliability, including the quality of incoming components, process control, and product transportation. Incoming components are like the cornerstones of a high - rise building. If the quality of the components is substandard, the reliability of the entire product will be seriously affected. Therefore, we need to conduct strict inspections and screenings on incoming components to ensure that they meet the product's quality requirements.
Process control is the key link to ensure product quality. In the production process, each process may have an impact on the reliability of the product. We need to establish a complete process control system, strictly monitor and manage the parameters and operations of each process to ensure that the product can meet the quality standards at every stage. Factors such as bumps and vibrations during product transportation may also damage the reliability of the product. Therefore, we need to adopt appropriate packaging and transportation methods to protect the safety of the product during transportation.
After we have improved a manufacturing process and established new reliability standards, we must ensure that these improvements are consolidated, and it is not allowed for the product quality to revert to the original standard. This requires us to establish effective supervision and evaluation mechanisms to regularly inspect and evaluate the reliability of products. The reliability control of products is not only limited to the products themselves, but also includes multiple aspects such as the reliability control of new product design, the reliability control of incoming materials, and the reliability control of product production. There are complex scientific methods embedded in all aspects of product reliability control. The deeper managers study these methods, the easier it is for them to do a good job in product reliability control, thereby improving the product quality and market competitiveness.