Reliability Integration across the Product Life Cycle

Mike Silverman
Ops a la Carte

Reliability is no longer a separate activity performed by a distinct group within the organization. Product reliability goals, concerns and activities are integrated into nearly every function and process of an organization. Senior management’s role is to foster an environment where the team keeps reliability and quality as defined by the customer clearly in mind. Engineering teams, whether in-house or contracted with design firms such as Nuvation, balance cost, time-to-market, performance and reliability to achieve optimal product designs. The organization structure encourages all members of the team to apply appropriate reliability methods and principles.


Reliability Integration for the Organization

To achieve the desired reliability levels customers demand, an organization must understand the reliability process and manage it as a process. Establishing clear Reliability Policies, Goals and resources, the reliability process guides product design and delivery. Periodically, you should examine your current situation by performing a Reliability Program Assessment. Competitive Analysis and careful examination of the customer expectations around reliability help you gage your expectations. Along the way, a suite of Reliability Metrics provide the dashboard to monitor the reliability process. And occasionally, new standards such as Removal of Hazardous Substances (RoHS)/Lead Free Solder provide new reliability challenges and an entire program must be recalibrated.

Reliability Integration in the Concept Phase

Reliability Goal Setting and establishing a plan to achieve the goals characterize this phase. Reliability goals are part business decision, part technology capability and part customer driven. Benchmarking provides an external view of industry reliability programs, processes and standards in use, plus a view of customer expectations. Gap Analysis highlights deficiencies between your current situation and goals. A Technology Risk Assessment examines the product concept to identify high reliability risk elements. Armed with this information you can then develop a realistic Reliability Program and Integration Plan. This plan is the critical roadmap to guide product development to meet reliability goals.

Reliability Integration in the Design Phase

Key to a reliable product is the many design decisions, and for each decision, designers balance reliability with cost, time-to-market and performance objectives. Reliability Models and Predictions provide prioritization and feedback for each decision. Analysis of the system reliability or availability connections to key modules or components through Reliability Block Diagramming or Fault Tree Analysis help establish realistic sub-system goals and identify high risk areas in the design. Failure Modes and Effects Analysis provides a structured method to identify potential risks, their impact, and mitigation effectiveness.

A wide range of methods are available to the design engineer to make decisions.  Heat is a common accelerant of failure mechanisms; therefore, Thermal Analysis techniques provide feedback to minimize this.  Proper Derating Analysis minimizes a wider range of stresses for electronic components.  For mechanical components Tolerance or Worst Case Analysis performs a similar function.  For complex design issues, statistical methods including Design of Experiments can quickly optimize reliable solutions.  On early designs a Sneak Circuit Analysis provides a check for unintended product behavior (hardware/software design defects).  Software also has reliability concerns; therefore, Software Reliability techniques can establish well documented methods to produce nearly bug free code.

As the design evolves, key elements of information provide other parts of the organization critical information. Warranty Prediction assists in key business decisions.  The expected product failure rate over time feeds into Preventive Maintenance and Supportability & Maintainability considerations in the design.  Plus, effective Design Reviews and Retrospective Events help the organization identify, remove, and avoid reliability issues.


Reliability Integration in the Prototype Phase

Discovering design weaknesses and verifying achievement of reliability goals becomes possible with prototypes. The Reliability Test Plan tailors the suite of evaluations to each development project for an effective and efficient product assessment. A very rapid way to discover design weaknesses is with the Highly Accelerated Life Testing (HALT) approach.  The elimination of electrical and mechanical flaws pushes the design margins as wide as possible.

Design Verification Testing and Environmental Testing confirm that a product will meet established reliability goals in the customer’s environment.  Thermal Testing can reveal heat-related issues.  Accelerated Life Testing is often used at this stage on select high risk modules or key components to develop reliability life models.  In some circumstances you may need to conduct a formal Reliability Demonstration Test - these are often statistically based and built on the design and testing knowledge leaned throughout the development process.

We must also perform Package Design and Testing to assure our shipping containers will withstand our shipping environment. And in parallel, we must prove product compliance to safety and emissions standards around the world with our Regulatory Compliance Testing and Certification. And prior to releasing to manufacturing, we must design and fabricate the appropriate Test Fixtures.

Each failure is fully analyzed to root cause using the Closed-Loop Corrective Action process. It is the combination of rapid discovery of flaws, careful analysis of expected failure mechanisms and thorough root cause analysis that permits the best set of final design decisions before product launch.


Reliability Integration in the Manufacturing Phase

As the product transitions to manufacturing, the reliability goals, models and test results become the basis for refining reliability screening, monitoring and reporting.  Establishing a Highly Accelerated Stress Screen (HASS) identifies and eliminates infant mortalities.  To protect from time dependant failure mechanism and to monitor the projected life estimates, conduct an On-Going Reliability Test.

Vendors also play an important role in achieving the product reliability goals.  Critical components or key vendors may need assistance getting their reliability program started or improved.  A Vendor Reliability Program Assessment is a quick way to identify and work to improve vendor reliability.

Record field performance and compare to Reliability Demonstration Test and On-Going Reliability Test results, as well as to the Reliability Predictions.  Perform root cause analysis on any deviations.  The field performance also feeds into the Field Failure Tracking System which monitors progress toward resolution of each issue.

A Warranty Performance Analysis monitors and compares against goals, plus provides a method to detect and track class defects that have escaped to the field.  The tracking system also permits periodic Reliability Performance Reporting which compares field results to the metrics first established in the Reliability Program and Integration Plan.

After the product has been in the field for a period of time, perform a product End-of-Life Assessment to determine when the product starts approaching end-of-life.  The Reliability Prediction and Failure Modes and Effects Analysis predict end-of-life and the Reliability Demonstration Test measures end-of-life (for susceptible components).  Based on these analyses and tests, as well as the trend of data from the field, you can determine when to alter repair policy and when to start offering upgrades and trade-ins.
Throughout the product life cycle, many decisions are made, some of which will later prove to be incorrect or less than optimal.  Establishing a Lessons Learned Process will help to collect the key information so that you learn from each product you develop, thereby increasing the reliability of each successive product.

About Ops A La Carte
Ops A La Carte is a professional consulting firm focused on Reliability Engineering Services, Reliability Management, and Reliability Education to assist companies in developing and executing any and all elements of reliability throughout an organization and product life cycle.  We continue to offer all of our services "a la carte".  However, many customers prefer for us to recommend which services are appropriate for their situation, and our Reliability Program Assessment service is perfectly geared to do this..  Ops A La Carte and Nuvation frequently collaborate on new product developments where we leverage eachother’s strengths to not only accelerate time-to-market but ensure that the product reliability goals are set, measured, and attained. 
For more information about incorporating Reliability Engineering and Reliability Management into your programs, please contact your Nuvation account manager or contact Ops A La Carte directly.  www.opsalacarte.com   

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