on Product Reliability

Quality: A Snapshot at Time Zero

Quality is a measure of how well a product meets specified requirements and standards at the beginning of its life. It’s a static measure that can be controlled and measured with accuracy. Quality engineers focus on designing and implementing quality control processes, conducting inspections and testing, and identifying and addressing defects or issues.

Given the reliability goal for a system, we often need to understand the reliaility goals for elements within the system. It is a balance between safety, cost, and performance. This short video discussed how to approach allocating reliability goals within a complex system.

Software reliability and hardware reliability are two distinct concepts within the field of engineering, each with its own unique characteristics and measurement challenges.

Software reliability is defined as the probability that software will operate without failure for a specified period of time in a specified environment. It is a reflection of the design perfection rather than manufacturing perfection, which is more associated with hardware reliability. The complexity of software is a major contributing factor to software reliability issues. Unlike hardware, software does not degrade over time or wear out, but it may have faults due to design defects that can cause failures.

Once a problem is clearly identified, the team must gather information concerning the problem, and identify potential solutons. After evaluating the potential solutions, the team can select the solution that will solve the problem effectively. It is then time to plan the details on the design change implementation.

Accelerated Life Testing (ALT) is a method used in reliability engineering to assess the lifespan and performance of a product under accelerated stress conditions. The goal is to uncover potential faults and failures in a shorter time frame than would be possible under normal operating conditions. ALT is particularly useful when the product’s expected lifespan is long, and waiting for failures to occur naturally is not feasible.

In the context of Design Verification (DV), ALT can help shorten the testing time by inducing failures more quickly than under normal conditions. This allows engineers to identify and address potential issues earlier in the product development process, thereby improving the product’s reliability and reducing the time to market. [Read more…]

The importance of failure repeatability lies in its role in understanding and improving systems, processes, and products. Failure repeatability refers to the consistency with which a system or device can reproduce an outcome under unchanged conditions. In the context of product design engineering and testing, being able to consistently replicate a failure means that the underlying cause can be more accurately identified and addressed.

Degradation testing for electromechanical components such as pumps, valves, and sensors involves a series of steps to identify wear and tear that could lead to system failure. The goal is to detect these signs of degradation early enough to replace the part and prevent system failure.

For pumps, degradation can be monitored by sensors. A study on gear pumps used an accelerated life test (ALT) to monitor the degradation state. The volumetric efficiency of the pumps was measured over time, and the wear clearances were recorded. As the wear gap increased, the flow rate gradually decreased, indicating wear degradation.

The 5-Whys approach in product development enhances reliability by understanding failure modes. The 5-wys technique is a powerful tool for root cause analysis. Originally developed by Sakichi Toyoda and later popularized by Keiichi Ono.

Preventive maintenance is a proactive approach used by industries to ensure the longevity and optimal performance of their assets. It involves regular maintenance tasks such as cleaning, lubrication, parts replacement, and equipment repairs to prevent unplanned downtime and costly breakdowns.

Software reliability and Hardware reliability are two distinct Concepts within the field of engineering each with its own unique characteristics and measurement challenges.

Understanding the different types of data and their respective uses is critical for product development, testing, and analysis. Each type of data plays a role in ensuring that products meet quality standards and fulfill user needs. As a mechanical engineer with a focus on R&D testing and data analysis, you would likely encounter and utilize these various data types throughout the product development and validation process.

Defining a proper product reliability goal is a critical step in ensuring that a product meets customer expectations and performs adequately throughout its intended lifespan. This also involves a careful balance between the required level of reliability and the associated costs and complexities of achieving that reliability.