Highly accelerated Life Testing HALT in Barco

Transcription

1 Highly accelerated Life Testing HALT in Barco 2007 Ivan Malfait

2 Topics HALT in Barco Situating HALT in Barco How it started Current situation: The HALT Installation itself Situating HALT in the Design Process? The HALT Procedure Practical Tips Operating Cost Other HALTs HASS

3 Situating HALT in Barco

4 How it started in with Long Term HALT Temperature cycling only on Qualified units Target 1: 500 hours before release of design Target 2: 3500 hours in total HIGH ACCELERATED LIFE TEST PROFILE 70 C C -10 C -20 C POWER ON POWER OFF manufacturing release if: -500 h It needs to be taken into account that condensation occurs after one hour at 25 C. -10ºC to 70ºC: 2cycles/day. 70ºC to -10ºC: 3 cycles/day. 21 hours operational/day. - If all malfunctions have a root cause analysis and a corrective action is implemented.

5 Current situation Short Term HALT The installation itself In the lab Chamber itself Pipes Inside..... Safety aspect Outside the lab Pipes External Thermal isolation by Vacuum Liquid Nitrogen Tank L (4500 L useful) Telemetry Neverempty

6 Situating HALT in the Design Process For new or derived products During the Design and before final qualification. To compare same product of different competitors For finalized products To simulate field failures Test objects 1. Board level assemblies 2. Electronic/ Electromechanical Equipment Business Case Evaluation BCR Preliminary Design PDR Prototype/ Alpha stage CDR Pre-series/ Beta stage FQR Series POR Pre-Study CLR SRR Phase-out EOL

7 Before HALT The HALT Procedure 1. Define a HALT team with multiple disciplines (Project Leader, Mech. resp, Elect. resp, Test executer) Mech. Resp. and Elect. Resp: looking for root causes and implement corrective actions 2. Define the EUT and how to test (closed, open, cabling, ), fixation 3. Get the Operating Temperature and Vibration specifications (from Marketing/Sales or Customer).. 4. Define the Target Operational Limits for Temperature and Vibration.. 5. Make an FMT (Functional Monitoring Test) and define the coverage (must cove at least the major functionality). 6. Check LN2-Volume left before extensive testing. 7. Fix the EUT in the chamber. Vibration Jig: stiff (transferring vibration energy at all frequencies) low thermal inertion (cooling and heating rate) open structure (air flow) low weight (G level) minimum number of resonances 8. Connect the accelerometers and the thermocouples. 9. Run at least one FMT cycle before start of HALT

8 During HALT The HALT Procedure 1. Continuously perform the FMT (it is not a humidity test!) 2. Monitor all HALT Parameters as a function of time (Temp, Vibr, FMT, ) 3. List the deviations, if any What should be corrected / what not (LCD clearance, Deformation of plastic housings, )? Perform root cause analysis Implement a corrective action Cost of corrective action (time and material)? Delay in product release? Risk of non-implementation? Benefit for other products? Fundamental limit of technology? Note: Do not explain issues away as this does not improve the reliability. It is a repeated Stress Fail Fix process. Perform a verification HALT

9 1. Thermal Step Stress Test LTOL The HALT Procedure FMT 45 C/min Start at ambient Temperature 10 C Decrements UTOL Minimum dwell time = 12 minutes

10 The HALT Procedure 2. Rapid Temperature Cycling Minimum 3 thermal cycles UTOL 5 C LTOL + 5 C Minimum dwell time = 10 minutes 3. Vibration Step Testing (VOL) Start at 5 g RMS 5 g RMS Increments FMT Minimum dwell time = 12 minutes

11 4. Combined Testing The HALT Procedure FMT 5 Temperature cycles UTOL 5 C LTOL + 5 C FMT Vibration step = (VOL 5 g RMS ) / 5 Target is 5 complete combined test cycles.

12 The HALT Procedure 5. Thermal Step Stress Test (if no Destructive Limits are encountered during previous testing) LTDL UTDL

13 The HALT Procedure After HALT 1. Make report (Report should be finished as Test is finished) Product identification Description of product fixture Location of response sensors Deviations from the standard HALT process FMT Detail of occurrences of unit degradation Root cause analysis + Corrective actions implemented (Resulting in Engineering Changes) Summary of reached levels 2. Store all HALT data (so that the test sequence can be reproduced afterwards). 3. Clean up. 4. Keep test unit (if possible).

14 The HALT Procedure HALT in Barco is considered as being successful when: target limits are reached, when failures occur, the failures are understood, corrective actions are taken, the product limits are clearly defined and pushed as far as possible.

15 Practical Tips have knowledge of the equipment LN2 Storage LN2 Pressure stabilization (how it works) Max cooling performance versus max efficiency Air pressure & Flow rate fixation of EUT & pipes

16 Operating Cost Renting of the LN2 tank LN2 Consumption Electricity / Compressed air Operator (Almost Full Time) LN2 Consumption LN2 Consumtion / day Refill Volume [L] /Dec/ 17/Feb/2 8/Apr/20 28/May/2 17/Jul/2 5/Sep/2 25/Oct/2 14/Dec/ 2/Feb/20 24/Mar/2 13/May/ time [-] Refill Quantity LN2 Consumption / day Linear (LN2 Consumption / day) Linear (Refill Quantity)

17 AVIONICS HALT Projects done 1. Unit 1: Underfill Simulation of BGA failure in the field. 2. Unit 2: Broken connections underneath QUASAR chip 3 Ethernet failures have occurred during the test: Abnormal flickering image on the display The unit reboots automatically when this failure occurs. Combo card is resetting at random (this reset is typically triggered by the main processor board) Front of the EUT appears to reboot at random. 3. Unit 3: The bottom plate of keyboard tablet has become loose during the Vibration Operation Limit (VOL) test Coil L6 (part of 3V3 switching regulator) has become loose from the plastic footprint with a broken inductor wire finally

18 DEFENCE Unit 1: HALT Projects done Light leak on top of the unit that has become worse during the Short Term HALT. Bad contact in the LCD connector (J5) on the PDB-Board of the Unit. Electrolytic capacitor C388 on the VPB-Board of the VCM-1102 that has shortened. Isolation of the VECTORLINK cable on the PM-side does become loose. Unit 2: one or more backlight lamps are not functioning anymore. Bad contacts electrolytic capacitors

19 HALT Projects done MEDICAL Unit 1: Backlight (test of cracks in Light Guide) Unit 2: (with witnessing) A vertical tab is broken after about 3 minutes light-leaks are visible at the bottom of the display 5 electrolytic capacitors have broken off Optical link does not function anymore USB link does not function anymore

20 Other HALTs Rapid Voltage variation (determination of the Voltage margin) Power (On/Off) cycling (5000 cycles and perform FMT after each 500 cycles)

21 Business Case Evaluation BCR Preliminary Design PDR Prototype/ Alpha stage CDR Pre-series/ Beta stage Pre-Study CLR SRR HASS During manufacturing, based on a finished design Replaces the current Temp. Screening (Burn-in) The limits discovered during HALT are used as the basis for setting the HASS parameters Detect weaknesses that are possibly introduced during manufacturing (done on a finished product). Shorter screening time (5 hours instead of 24 or 48 hours) Based on same equipment (with or without vibration). Check differences between chambers (T and Vibration capabilities). FQR Series POR Phase-out EOL

22 HASS Temperature [ C] Precipitation Phase Open EUT Detection Phase Closed EUT UTOL+20 C UTOL UTOL-10 C +45 C/min. -45 C/min. Steepness depends on UTOL and LTOL Ambient temperature Time [min.] LTOL+10 C LTOL Vibration [Grms] VOL 0.8 * VOL Time [min.] Power to EUT Power interruption of 2 min. On Off 72 Time [min.] Start of Screening End of Screening

23 End

24 Telemetry

25 Pipes Inside Exhaust LN2

26 Chamber itself Model Typhoon 3.0 Vibration 6 degree of freedom (3 translations and 3 rotations). 10 Hz 5 khz 50 GRMS min. (no load) Thermal -100 C +200 C Max. 70 C/min. Useful Volume (91 x 91 x 89) cm³

27 Liquid Nitrogen Tank

28 Pipes External

29 Pipe that blows underneath the panel module Mechanical Fixation Front LCD 2 pipes for the EUT PM 1131 VCM 1102 Both parts are not completely closed Back of the PM: electronics boards are not covered

30 EUT To increase thermal transition rate

31 Defining the Target Operational Limits No standard known, only guidelines, product dependent For Barco Defined Products, the specification is the basis. Target UTOL = Spec + 48 C Target LTOL = Spec 48 C Target VOL = 20 GRMS + 12 GRMS 35 GRMS

32 The Target Operational Limits Low margins indicate poor performance (short life), High margins indicate good performance (longer life). Typical Medical Products, Target UOL = +45 C + 48 C = + 95 C Target LOL = 0 C 48 C = - 48 C Target VOL = 20 g + 12 g => 35 g Typical Avionics Products, Target UOL = +55 C + 48 C = C Target LOL = -25 C 48 C = - 73 C Target VOL = 20 g + 12 g => 35 g Typical Defence Products, Target UOL = +63 C + 48 C = C Target LOL = -42 C 48 C = - 90 C Target VOL = 20 g + 12 g => 35

33 Position of accelero s Measured level differs a lot from setpoint Measured Level almost equal to setpoint