TEST ENGINEERING
Patrick OíConnor
Testing is usually the most expensive, time-consuming and difficult activity during the development of engineering products and systems. Development testing must be performed to ensure that designs meet requirements for performance, safety, durability, reliability, statutory aspects, etc. Most manufactured items must be tested to ensure that they are correctly made. However, much of the testing that is performed in industry is based upon traditions, standards and procedures that do not provide the optimum balance of assurance versus cost and time. There is often pressure to reduce testing because of the high costs involved, without appreciation of the effects on performance, reliability. etc. Misperceptions are commonplace, particularly the idea that tests should not stress products in excess of their operating levels.
The main reason for this situation seems to be that engineers have not developed a consistent philosophy and methodology for testing. Testing is seldom taught as part of engineering curricula, and there are no books on the subject. Specialist areas are taught, for example fatigue testing to mechanical engineers and digital device testing to electronics engineers. However, a wide range is untaught, particularly multidisciplinary and systems aspects. Testing is not just an engineering issue. Because of the importance and magnitude of the economic and business aspects testing is an issue for management. Testing is perceived as a high cost activity, when it should be considered as a value-adding process.
The objective of this seminar is, therefore, to propose a philosophy of engineering test and to describe the necessary technologies and methods that will provide a foundation for all plans, methods and decisions related to testing of engineered products and systems. It will help those who must manage and conduct this most difficult and uncertain task.
The seminar is based upon Pat OíConnorís new book, "Test Engineering", John Wiley (2001). Copies will be provided to seminar attendees.
For details of the book, and to buy it, visit Test Engineering.
SEMINAR OUTLINE
1. INTRODUCTION
Why test?
How to test? Test to succeed, or test to fail?
Analysis and simulation
Good and bad testing
Test economics
Managing the test programme
2. STRESS, STRENGTH AND FAILURE OF MATERIALS
Introduction
Mechanical stress and fracture
Fatigue
Vibration and shock
Creep
Temperature effects
Wear
Corrosion
Humidity and condensation
Materials and components selection
3. ELECTRICAL AND ELECTRONICS STRESS, STRENGTH AND FAILURE
Stress effects
Component types and failure mechanisms
Circuit and system aspects
4. VARIATION AND RELIABILITY
Variation in engineering
Load-strength interference
Time-dependent variation
Multiple variations and statistical experiments, Taguchi method
Confidence and significance
Reliability
Quality function deployment
Design analysis methods
Mathematical
Mechanical
Electrical/electronic
Systems, general
Monte Carlo simulation
Other system simulation methods
Analysis methods for reliability and safety
Load and strength analysis
Failure modes and effects analysis
Sneak analysis
Fault tree analysis
HAZOPS
Design analysis for processes
Process FMEA
"Poka yoke"
Testability analysis
Test yield analysis
Maintainability analysis
Software for design analysis
Limitations of design analysis
Using analysis results for test planning
6. DEVELOPMENT TESTING PRINCIPLES
Functional testing
Testing for reliability and durability; accelerated test
Test approach for accelerated test
HALT and production testing
Common questions on HALT
Overall benefits of HALT and HASS
Testing for variation: Taguchi method
DoE or HALT?
Process testing
Process capability studies
"Beta" testing
Materials
Assemblies and systems
Data collection and analysis
Standard test methods
Test centres
8. ELECTRONICS
Circuit test principles
Analogue
Digital
Test equipment
Manual test equipment
Automatic test equipment
Test data acquisition
Design for test
Test capability
Test software
Scan design
Built-in self-test (BIST)
Electronic component test
Discretes
Integrated circuits
IC design for test
EMI/EMC testing
9. SOFTWARE
Software in engineering systems
Software errors
Preventing errors
Analysis of software system design
Data reliability
Software testing
10. MANUFACTURING TEST
Manufacturing test principles
Value added testing
Test capability
Test criteria
Test stresses
Manufacturing test economics
Inspection and measurement
Test methods
Mechanical and systems test
Electronics
Stress screening
Highly accelerated stress screening
Electronics manufacturing test options and economics
Circuit board test
Assembly test
Integrating stress screening
Post-production savings
Conclusions
Testing electronic components
Integrated circuits
Statistical process control and acceptance sampling
In-service test economics
Test schedules
Mechanical and systems
Electronic and electrical
Built in test
"No fault found"
Software
Reliability centred maintenance
Stress screening of repaired items
Calibration
12. DATA COLLECTION AND ANALYSIS
Introduction
Failure reporting, analysis, and corrective action system (FRACAS)
Procedure for FRACAS
Failure reporting forms
Failure data analysis: the "7 tools"
Acceptance sampling
Probability and hazard plotting
Time series analysis
Software for data collection and analysis
Reliability demonstration and growth measurement
Reliability demonstration
Reliability growth monitoring
General comment on data analysis
Sources of data
13. LAWS, REGULATIONS AND STANDARDS
Laws and regulations
Main regulatory agencies
Standards (International, USA, Europe, etc.)
"Generic" standards
ISO 9000 (Quality Systems)
IEC 300 ("Dependability")
IEC 61508 (Functional Safety of Electrical/Electronic Safety-related Systems)
Industry/technology standards
Aviation and aerospace
Automotive
Other industries
14. TEST MANAGEMENT
Organisation and responsibilities
Procedures for test
The development test programme
What to test?
How many to test?
System levels for test
Testing purchased items
Hardware allocations to test
Test methods
Development test economics
Use of external test facilities
The project test plan
Manufacturing and maintenance
Training and education for test
The future of test
Virtual testing
Intelligent CAE
The internet
Test hardware
Teaching testing
Conclusions