highly accelerated life testing halt in barco 2007

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Highly accelerated Life Testing Highly accelerated Life Testing HALT in BarcoHALT in Barco

2007

Ivan Malfait


HALT in BarcoTopics

• 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


Situating HALT in Barco


How it started in … with “Long Term” HALTTemperature cycling only on Qualified units

Target 1: 500 hours before release of design

Target 2: 3500 hours in total

manufacturing release if:

- 500 h

- If all malfunctions have a root cause analysis and a corrective action is implemented.

0

9

4

6 7

8

5

32

1

10 11

12

14

1317

15

16

18

10

0 1

15 6 987 1514131211 2019181716 24232221 5432

70°C

25°C

-10°C

-20°C

2

It needs to be taken into account that condensation occurs after one hour at 25°C.

HIGH ACCELERATED LIFE TEST PROFILE

POWER OFF

POWER ON

-10ºC to 70ºC: 2cycles/day.70ºC to -10ºC: 3 cycles/day.21 hours operational/day.


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 …........…• 5000 L (4500 L useful)

•Telemetry …………………………•Never empty


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

Business Case Evaluation

PreliminaryDesign

Prototype/Alpha stage

Pre-series/Beta stage

Series

Phase-out

Pre-Study

BCR

PDR

CDR

FQR

POR

CLR

SRR

EOL

1. Board level assemblies

2. Electronic/ Electromechanical Equipment

Test objects


The HALT Procedure1. 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

Before HALT


The HALT ProcedureDuring HALT

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 ?

• Perform a verification HALT

Note: Do not “explain issues away” as this does not improve the reliability. It is a repeated “Stress – Fail – Fix” process.


The HALT Procedure1. Thermal Step Stress Test

LTOL

UTOL

Start at ambient Temperature

10 °C Decrements

Minimum dwell time = 12minutes

FMT 45 °C/min


The HALT Procedure2. Rapid Temperature Cycling

3. Vibration Step Testing (VOL)

Minimum 3 thermal cycles

UTOL – 5°C

LTOL + 5°C

Minimum dwell time = 10 minutes

Start at 5 gRMS

5 gRMS Increments

Minimum dwell time = 12minutes

FMT


The HALT Procedure4. Combined Testing

5 Temperature cycles

UTOL – 5°C

LTOL + 5°C

Target is 5 complete combined test cycles.

FMT

FMT

Vibration step = (VOL – 5 gRMS) / 5


The HALT Procedure5. Thermal Step Stress Test (if no Destructive Limits are encountered

during previous testing)

LTDL

UTDL


The HALT ProcedureAfter 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).


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.


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


Operating Cost• Renting of the LN2 tank • LN2 Consumption• Electricity / Compressed air• Operator (Almost Full Time)

LN2 Consumption

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1000

2000

3000

4000

5000

6000

29/Dec/2004

17/Feb/2005

8/Apr/2005

28/May/2005

17/Jul/2005

5/Sep/2005

25/Oct/2005

14/Dec/2005

2/Feb/2006

24/Mar/2006

13/May/2006

time [-]

LN2

Con

sum

tion

/ day

Re

fill V

olum

e [L

]

0

500

1000

1500

2000

2500

3000

Refill Quanti ty LN2 Consum ption / day Linear (LN2 Consumption / day) Linear (Refill Quantity)


HALT Projects doneAVIONICS

1. Unit 1: Underfill Simulation of BGA failure in the field.

Broken connections underneath QUASAR chip

2. Unit 2:

3. Unit 3:

• 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.

•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


HALT Projects doneDEFENCE

• Unit 1:

• Unit 2:

• 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.

• one or more backlight lamps are not functioning anymore.• Bad contacts electrolytic capacitors


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


Other HALTs

• Rapid Voltage variation (determination of the Voltage margin)

• Power (On/Off) cycling (5000 cycles and perform FMT after each 500 cycles)

• …


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).

Business Case Evaluation

PreliminaryDesign

Prototype/Alpha stage

Pre-series/Beta stage

Series

Phase-out

Pre-Study

BCR

PDR

CDR

FQR

POR

CLR

SRR

EOL


HASS

UTOL+20°C

UTOL-10°C

Ambient temperature

LTOL+10°CLTOL

Time [min.]

Temperature[°C]

0.8 * VOL

0

Vibration [Grms]

Time [min.]

VOL

5

12 12 12 3015 305 5 1515

0 60 120 180

15 30 305 5 30

Power to EUT

On

OffTime [min.]

Power interruption of 2 min.

72

Start of Screening

End of Screening

+45°C/min.

-45°C/min.

72 115

Precipitation Phase

Detection Phase

Steepness depends on UTOL and

LTOL

UTOL

12 1212

72

Closed EUTOpen EUT


End


Telemetry


Pipes Inside

LN2Exhaust


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 à +200 °C

Max. 70 °C/min.

Useful Volume

(91 x 91 x 89) cm³


Liquid Nitrogen Tank


Pipes External


Mechanical Fixation

VCM 1102

PM 1131

Front LCD

Back of the PM: electronics boards

are not covered

Pipe that blows underneath the panel module

2 pipes for the EUT

Both parts are not completely closed


EUT

To increase thermal transition rate


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 à 35 GRMS


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 = + 103 °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 = + 111 °C• Target LOL = -42 °C – 48 °C = - 90 °C• Target VOL = 20 g + 12 g => 35


Position of accelero’s

Measured level differs a lot from setpoint

Measured Level almost equal to setpoint

highly accelerated life testing halt in barco 2007

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