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Reliability Engineering and Management

Table of Contents - Detailed Version 

Reliability engineering management 

Early warning devices – reliability concepts, techniques and tools

Evaluating designs by test (test programs, integrated test programs) 

Establishment of reliability data systems / programs

Statistical concepts, tools, standards, software used in reliability data analysis

Acting in an advisory, problem-solving support and training capacity  

§       Reliability engineering management 

×   Spanning all reliability tasks and management actions taken, including the following:

›      Requirements / goals definition, program planning / implementation for the entire development cycle, design standards / criteria.

›      Numerical analyses, e.g. reliability prediction and analysis, reliability assessment / growth.

›      Design analyses, e.g. electrical / optical / thermal analyses, failure mode and effect analysis (FMEA), electrostatic discharge (ESD), latch-up sensitivity analysis, risk analysis, functional / design / program reviews, change analysis / review.

›      Parts, materials, processes (PMP) control, to minimize the potential negative impact of critical reliability issues, e.g. PMP selection, process controls, process baseline definition / controls, PMP specification controls, part qualification program, material and process qualification.

›      Testing, e.g. qualification / acceptance testing, life / accelerated life testing, step-stress / robustness testing.

›      Environmental stress screening, e.g. incoming tests / screens, burn-in, highly accelerated stress screening.

›      Failure reporting, analysis and corrective action, e.g. data collection, yield analysis, field data analysis, failure review board, failure reporting and corrective action system (FRACAS), failure analysis laboratory.

§       Early warning devices – reliability concepts, techniques and tools

×   Reliability quantification, prediction and analysis processes, in conjunction with statistical concepts / methods. Reliability figures of merit, e.g. mean time to failure (MTTF).

×   Design review along with reliability evaluation techniques.

×   Concept of growth curves to predict future performance from test / early field data.

×   Parts, materials and processes control programs.

×   Failure modes and effects analysis (FMEA) for product / process design. Fault tree analysis.

§       Evaluating designs by test (test programs, integrated test programs)  

Focus on three elements – performance requirements, environmental conditions during use, and time requirements.

×   Environmental stress screening (ESS).

›      Conducted at lower levels of the product to identify early failures due to weak parts, workmanship defects and other reasons for non-conformance.

›      ESS combined with life testing to help identify weak points in new designs.

×   Reliability development / growth tests / program.

›      Performed before final release of the design to improve product reliability through identification, analysis and correction of failures, and verification.

×   Reliability qualification tests / program.

›      Conducted on product, representative of the approved production configuration, to provide assurance that the product meets the formal reliability requirements.

×   Production reliability acceptance tests / program.

›      Periodic evaluations of reliability of production hardware, particularly when any changes have been made in design, tooling, processes, parts or other characteristics.

×   Integrated test programs.

›      With a number of tests integrated so that one type of test can serve several purposes, e.g. evaluation of both performance and environmental capabilities.

§       Establishment of reliability data systems / programs

×   Reliability data systems, to serve important purposes, such as 

›      To detect current reliability problems and assist in their solution.

›      To provide quantitative information on product performance and the status of problems.

›      To assist in reliability improvement programs.

›      To provide failure history and other reference data for use in product changes and in future products.

×   Reliability improvement programs, identified through

›      Reliability prediction, design review, FMEA, and other reliability evaluation techniques.

×   Manufacturing reliability improvement program, based on improvement actions to be identified, such as:

›      Increased operator training, process stabilisation test, increased product audit, dedicated corrective action support.                     

×   Failure reporting and integrated corrective action system (FRACAS).

×   Reliability engineering program, based on customer usage profiling and reliability specifications, comprising the building blocks of

›      Reliability testing during product progression, manufacturing through to customer use.

›      Master database including test log, failure log, service log.

›      Data analysis, reporting and FRACAS.   

×   Reliability assurance program spanning reliability planning through to field operation.  

§       Statistical concepts, tools, standards, software used in reliability data analysis

×   Life or failure distributions: Normal. Lognormal. Exponential. Weibull.

›      Mathematical functions, including

-      Probability density function. Cumulative density function. Reliability function. Hazard rate.

›      Significant parameters, including

-      t₅₀, t₇₅, for example, are the times by which 50%, 75% of the items in a sample will have failed.

-      Location parameter of a distribution locates it in time; for a normal distribution location parameter is the mean.

-      Shape parameter provides a quantitative measure of the shape, or spread. For a normal distribution it is the standard deviation.

×   Reliability data evaluation by graphical methods (cumulative distribution function plotting).

›      Normal, lognormal, exponential, Weibull probability plotting.

›      Mean time between failures (MTBF) calculations (failure- / time-terminated tests with and without replacements).

›      Confidence limits on MTBF estimates.

×   System reliability calculations.

×   Risk analysis (failure modes, effects and criticality analysis (FMECA)).

×   Reliability growth monitoring.

›      Plotting of cumulative MTBF versus time throughout development stage.

×   Reliability tests performed according to industry standards, such as

›      ISO/TS, JEDEC, AEC-Q100, Telcordia GR-468 Core, military standards MIL-STD.

×   Software.

›      Reliability Analysis Software™ (Relest and Accelife modules) and

›      Diverse packages from ReliaSoft Corp.

§       Acting in an advisory, problem-solving support and training capacity

×   Reliability engineering management, including basic reliability engineering tasks and management actions.

×   Appropriate controls to minimize the potential negative impact of critical reliability issues

×   Development of a reliability engineering program with high problem-solving potential and associated benefits.

×   Establishment of a supplier reliability program.

×   Conduct of FMEA sessions to identify and document potential failure modes early in an NPI project.

×   Establishment of a reliability test / failure analysis laboratory.

×   Root-cause analysis of failed devices: Establishment of effect-cause relationships.

×   Establishment of a quality assurance failure analysis system.

×   Establishment of models on the physics of device degradation modes.

×   Training in reliability engineering concepts, techniques and tools.

×   Collection and analysis of inspection, stress screening, test, and other failure data to the degree necessary

›      To identify failure trends, and to serve as a basis for problem investigation, corrective action and feedback for future designs.

 

 

 

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