Preventing Thermal & Vibration Failures

Instructor: Steve Carlson - 2 Day Seminar

SEMINAR OBJECTIVE

This 2-day seminar will focus on:

1. To understand how variations in coefficients of thermal expansion (CTE) can affect the magnitude of the displacements, forces, and stresses that are developed in electronic assemblies during thermal cycling environments, and how these factors affect fatigue life.

2. To understand how resonant conditions can affect dynamic displacements, forces and stresses in electronic assemblies during different sine and random vibration environments.

3. To understand the concept of “damage accumulation” and how it can be used to determine the approximate fatigue life of various electronic assemblies due to different combinations of fatigue accumulated in thermal cycling and vibration environments.

This course is based upon the popular book Preventing Thermal and Vibration Failures in Electronic Equipment by Mr. Dave Steinberg.

Questions are encouraged during the Seminar, to make sure each participant understands the design techniques and applications presented.

WHO SHOULD ATTEND

R&D Electronic Engineers and Managers
Packaging Engineers
Quality & Reliability Engineers
Test Engineers
Manufacturing Engineers
Mechanical Engineers
Application & Sale Engineers

COURSE OUTLINE

PHYSICS OF FAILURE IN ELECTRONIC SYSTEMS

Areas That Require Analysis And Evaluation
How Thermal Cycling Environments Affect Fatigue Life
How Vibration Environments Affect Fatigue Life
Creep and Stress Relaxation in Solder
Combining Fatigue Damage From Many Different Environments

MOUNTING METHODS FOR VARIOUS TYPES OF ELECTRONIC COMPONENTS

· Different Types Of Electronic Components And PCB Mountings

· Fatigue Life Due To Various Component Geometry and Materials

· Package Types that Yield Rapid Fatigue Failure

Areas Where Minor Structural Changes Can Produce Large Increases In Fatigue Life

· Tips To Improve Heat Dissipation.

ESTIMATING FATIGUE LIFE – THERMAL AND VIBRATION ENVIRONMENTS

· Solder Thermal Cycle And Vibration S-N Fatigue Curves

· Solder Creep With Constant Stress And With Constant Displacement

· Solder Creep And Stress Relaxation

· Solder Creep Stress Relaxation As A Function Of Time

· Fatigue Damage In Structures Using Miner’s Cumulative Damage Criteria

· Relating Fatigue Properties To The Slope Of The Fatigue Curve

THERMAL EXPANSION DISPLACEMENTS, FORCES, AND STRESSES

· Reducing Forces And Stresses In Lead Wires And Solder Joints

· Coefficient Of Thermal Expansion Differences Leads To Relative Displacement

· Evaluate Axial And Bending Forces On Lead Wires and Solder Joints

Sample Problem: Solder Joint Shear Tear-out Stress and Lead Wire Bending Stress of Through-Hole Mounted Component during Thermal Cycling

THERMAL CYCLING STRESS FAILURES IN SURFACE MOUNTED COMPONENTS

Solder Shear Strain In Surface Mounted Components
Equilibrium Equation For Evaluating Thermal Expansion Forces and Stresses In The Solder Joints Of A Small LCCC

VIBRATIONS OF SIMPLE STRUCTURES AND PRINTED CIRCUIT BOARDS

· Determining The Natural Frequency of Beams and Flat Plates

· Effective Spring Rate For Springs In Series and Parallel

· Displacement, Forces, And Stress Due To Input Acceleration

· Damping And Transmissibility of PCBs And Other Electronic Structures

· PCB and Support Structure Dynamic Coupling

DESIGNING ELECTRONIC EQUIPMENT FOR SINUSOIDAL VIBRATION

How PCB Component Size, Location, And Orientation Effect The Fatigue Life
Sample Problem: TO-5 Transistor Lead Wire And Solder Joint Fatigue Life During Sine Vibration
Maximum allowable PCB Dynamic Displacement For Component Fatigue Life Of 10 Million Stress Cycles
Desired PCB Resonant Frequency For 10 Million Stress Cycles In Sine Vibration

ASSESSMENT OF RANDOM VIBRATION ON ELECTRONIC DESIGN

How Random Vibration Differs From Sinusoidal Vibration
Random Vibration Analysis Using The Three-Band Technique
Sample Problem: Estimating the Fatigue Life Using The Three-Band Technique With Miner’s Cumulative Fatigue Damage Ratio
Maximum allowable 3σ PCB Dynamic Displacement For Component Fatigue Life of 20 Million Cycles
Desired PCB Resonant Frequency For 20 Million Stress Cycles in Random Vibration

COMBINING THERMAL CYCLING AND VIBRATION FATIGUE DAMAGE

· Alternating Stress Superimposed Upon A Steady Stress

· Vibration Test Data Failures In Pin Grid Array Wires At Low Temperatures

· Combining Thermal Cycling And Vibration Damage

· Miner’s Combined Cumulative Fatigue Damage Criteria

FINITE ELEMENT ANALYSIS METHODS AND TECHNIQUES

· Finite Element Analysis (FEA) Methods To Determine Resonant Frequency, Forces, and Stresses

· Utilize Displacement, Forces, Stresses, And Temperatures From FEA To Determine Total Damage Due To Various Environments

CASE HISTORIES OF FAILURES AND FAILURE ANALYSIS

· Small Ceramic Chip Resistors And Capacitors

· Failures In Small Axial Leaded Through‑Hole Components

· Surface Mounted Transformer Lead Wire Failures

· Microprocessor Lead Wire Solder Joint Failures

· Relay Vibration Failures And Possible Screening Methods

· Hybrid Shock Failure Of Internal Die Bond Wires

· Cracked Casting Failure Analysis

INSTRUCTOR

Steve Carlson is a Mechanical Engineer Analyst at Northrop Grumman Navigation Systems Division in Woodland Hills, CA. He received his BSME at Arizona State University and MSME at California State University Northridge and has expanded the classical techniques developed by Mr. Dave Steinberg to include Solid Modeling and Finite Element Analysis to reduce analysis time, improve accuracy, and decrease product development time.

He has worked on the mechanical design, analysis, testing and packaging of cost effective sophisticated electronic equipment that must work with a high degree of reliability in harsh thermal, thermal cycling, vibration and shock environments. He has been involved in these areas related to commercial, industrial and military applications for many years. He is the Principal Engineer at Carlson Mechanical Engineering and has provided consultant services to multiple companies in the area of heat transfer, sine/random vibration, and computational fluid dynamics.

Mr. Carlson has worked on many aircraft, missile, and space programs for Litton G&CS, Northrop Grumman, and the Jet Propulsion Laboratory. These include the F-14, F-15, F-16, F-22, cruise missile, AMRAAM, Mars Science Laboratory (MSL), Gravity Recovery and Interior Laboratory (GRAIL), and Juno.

COST

2-day Seminar: $1,195 (U.S. Dollars) – Payment is due by seminar date. We accept VISA, MasterCard or American Express.

Register through our website or via e-mail: [email protected]