HALT and HASS - Envirotronics

®
HALT and HASS
›HALT/HASS Systems
Test Equipment For Highly Accelerated
Life Test and Stress Screen Applications
®
Life Test
Highly Accelerated
HALT precipitated defects by stress environment
The goal of every manufacturing company is
to bring a product of world-class quality to
market in the shortest time and for the least
expense. On top of that there is a further
incentive to improve field reliability and lower
warranty costs. Many manufacturers use
HALT and HASS to help them achieve these
goals.
Vibration step stress
= 45%
Combination of
6doF Vibration and
Rapid Temperature
= 20%
Hot step stress
= 17%
H
ALT is a step stress process
performed during the product’s
prototype phase that determines a
product’s operating limits, identifies design
weaknesses, and identifies weak components.
The prototype phase is the fastest and least
expensive point to make improvements.
In the HALT process, the test sample is
subjected to progressively higher stress
levels. Thermal dwells, rapid temperature
transitions, vibration, and a combination
of temperature and vibration are employed
to precipitate latent, inherent defects in the
design, at the component level, or in the
manufacturing process.
Beyond the precipitation of defects, HALT
stresses the product sample to failure.
Robustness of design and margin above
the product’s intended operating level are
determined. HALT is not a Pass/Fail test. It is
process of discovery and design optimization.
HALT is a success when failures are
produced, the root cause is understood,
corrective action is implemented and
product limits are understood and expanded.
Information learned during the HALT process
is used to develop a HASS screen for
monitoring deviations in the manufacturing
process.
2
Rapid Temperature
= 4%
Cold step stress
= 14%
Stress Screen
Highly Accelerated
H
ASS is a post-production process
that can be performed on 100% of
product or a partial sample of units
(HASA - Highly Accelerated Stress Audit).
The main goal of HASS is to precipitate and
detect hidden or latent failures. It is used to
verify that no new “weak link” has crept into
the product, since HALT, that has shifted the
limits found in HALT. Ultimately, its purpose
is to prevent flawed units from reaching the
end-user/customer.
Typically, HASS stress levels are less than
those used in HALT. However, they are
generally more severe than anticipated in
actual service. The goal is to use enough
stress to find faults - but not enough to
remove a significant amount of the product’s
life.
The benefits of HASS include:
• Precipitates hidden or latent failures
caused by poor workmanship or
manufacturing processes
• Verifies integrity of mechanical
interconnects
• Prevents flawed units from reaching the
end-user/customer (infant mortality/
out of box failure)
• Detects changes in components and
processes
• Decreases warranty and field service costs
• Increases customer satisfaction
• Exposes process related variations in
manufacturing
• Uncovers problems caused by changes to
both software and firmware
• Uncovers component supplier quality
issues and revision changes
HASS precipitated defects by stress environment
Combination of
6doF Vibration and
Rapid Temperature
= 46%
Extreme Temperature
Transitions
= 12%
High
Temperature
Extreme
= 12%
Low
Temperature
Extreme
= 12%
3
Profile
HALT
›The HALT Process
I
Examples of typical HALT profiles
110.0
25.0
87.5
Temperature (C)
12.5
Along with environmental stresses, product
specific stresses should also be applied to the
product, such as power cycling, line voltage
margining, line frequency margining, DC
supply voltage margining, output loading,
onboard oscillator margining and any other
applicable stresses.
0
-12.5
65.0
-25.0
42.5
-50.0
9:31
9:33
9:35
9:37
9:39
9:41
9:47
9:49
9:51
9:53
9:56
9:58
10:00
10:02
10:04
10:06
10:09
10:11
10:13
10:15
10:17
10:20
10:22
10:24
10:26
10:28
10:31
10:33
10:35
10:37
10:39
10:41
10:44
10:46
10:48
10:50
10:52
10:55
10:57
10:59
11:01
11:03
11:06
11:08
11:10
11:12
11:14
11:16
11:19
11:21
11:23
11:25
11:27
11:30
11:32
11:34
11:36
11:38
11:41
11:43
20.0
Time
Time
Vibration Step Stress
50.0
67.5
37.5
Temperature (C) / Vibration (Grms)
Temperature (C)
Rapid Thermal Transitions
110.0
25.0
-17.5
25.0
12.5
0
13:10
13:13
13:16
13:19
13:22
13:25
13:28
13:31
13:34
13:37
13:40
13:43
13:46
13:49
13:52
13:55
13:58
14:01
14:04
14:07
14:10
14:13
14:17
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14:23
14:26
14:29
14:32
14:35
14:38
14:41
14:44
14:47
14:50
14:53
14:56
14:59
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15:11
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15:29
15:32
15:35
15:38
15:41
15:45
15:48
15:51
15:54
15:57
16:00
16:03
16:06
16:09
-60.0
Time
Time
Temperature Setpoint
Combined Temperature and Vibration
Example:
Thermal Shock Portion of HALT
• 5 thermal cycles with thermal change
rates of 50°C per minute (or greater).
Rapid thermal cycling causes materials in the
product to expand and contract at different
rates, inducing stress and uncovering weak
spots in the design.
4
140
120
Temperature (C) / Vibration (Grms)
Temperature (C) / Vibration (Grms)
100
95
40
-15
80
60
40
20
0
-20
-40
-60
-80
-70
14:00
14:03
14:07
14:10
14:14
14:17
14:21
14:24
14:28
14:31
14:35
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14:49
14:53
14:56
15:00
15:03
15:07
15:10
15:14
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15:21
15:24
15:28
15:32
15:35
15:39
15:42
15:46
15:49
15:53
15:56
16:00
16:03
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16:25
16:28
16:32
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16:49
16:53
16:56
17:00
17:04
17:07
17:11
17:14
17:18
17:21
17:25
17:28
-100
10:33
10:42
10:44
10:47
10:49
10:52
10:54
10:56
10:59
11:01
11:03
11:06
11:08
11:10
11:13
11:15
11:17
11:20
11:22
11:25
11:27
11:29
11:32
11:34
11:36
11:39
11:41
11:43
11:46
11:48
11:51
11:53
11:55
11:58
12:00
12:02
12:05
12:07
12:09
12:12
12:14
12:16
12:19
12:21
12:24
12:26
12:28
12:31
12:33
12:35
12:38
12:40
12:42
12:45
12:47
12:50
12:52
12:54
12:57
12:59
13:01
13:04
• Cold or Hot step stresses in 10°C steps
• Power cycling performed at minimum
operating temperature +10°C.
• Add power cycling and voltage margining
to find additional failures. Voltage
margins should be tested beyond
specifications to expose design problems.
Vibration Step
Extended Temperature and Vibration
150
Example:
Temperature-Step Portion of HALT
11:44
11:47
11:49
11:55
11:57
11:59
12:02
12:04
12:06
12:09
12:11
12:13
12:16
12:18
12:20
12:23
12:25
12:28
12:30
12:32
12:35
12:37
12:39
12:42
12:44
12:46
12:49
12:51
12:54
12:56
12:58
13:01
13:03
13:05
13:08
13:10
13:12
13:15
13:17
13:19
13:22
13:24
13:27
13:29
13:31
13:34
13:36
13:38
13:41
13:43
13:45
13:48
13:50
13:52
13:55
13:57
14:00
14:02
-37.5
14:08
14:12
14:15
14:19
14:22
14:25
14:28
14:35
14:38
14:41
14:44
14:47
14:51
14:54
14:57
15:00
15:03
15:07
15:10
15:13
15:16
15:19
15:23
15:26
15:29
15:32
15:35
15:39
15:42
15:45
15:48
15:51
15:55
15:58
16:01
16:04
16:07
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16:27
16:30
16:33
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16:39
16:43
16:46
16:49
16:52
16:55
16:59
17:02
17:05
17:08
17:11
17:15
Test repeatability is the ability to reproduce
a failure mode; however, exact stress levels
to produce the failure may vary. Reproducing
a failure mode at a specific stress level is
not expected or required. In HALT what is
important is the failure, not the stress level
Hot Temperature Step Stress
Cold Temperature Step Stress
37.5
Temperature (C)
n HALT, product prototypes are subjected
to high levels of environmental stress from
least destructive to most destructive. The
HALT procedure employed will vary based
on the type of product being tested. Typically
these would be cold step test, hot step test,
thermal shock, vibration and combined
temperature and vibration.
Time
Temperature Setpoint
Time
Vibration Setpoint
HALT and HASS profile graphs appear courtesy of Reliant Labs
Temp Setpoint
Example:
Vibration-Step Portion of HALT
• Step stress vibration in 5 gRMS
increments, starting at 5 gRMS.
Once a diagnostic check has been completed,
vibration testing continues at the next level.
With Envirotronics’ powerful StarView
software, you have the ability to monitor your
product response as well as the table
vibration levels.
Vibration Setpoint
Example:
Combined Temperature and Vibration
Portion of HALT
•
•
Perform thermal cycles with thermal
change rates of 50°C per minute (or
greater).
Increase in 20% increments of the
operating limit. Dwell times of 15
minutes.
If no failure is produced, the rate of
temperature change is increased and the
vibration levels are increased.
Profile
HASS
HASS Development Product Life Valuation - 15 Runs
80.0
HASS Development
Proof of Screen
(POS) - 15 Runs
HALT testing stops when the limits of the
test equipment are met, when multiple
failures occur in rapid succession with small
increases in the stress level, or when the
maximum level of the materials or technology
has been reached.
The operational limit is is defined as the
stress necessary to cause a product to
malfunction, but the product returns to
normal operation when the stress is removed.
The destruct limit is the stress necessary to
cause a permanent or “hard” failure.
The difference between these limits is the
margin for that particular stress. As the
failure modes are found and eliminated, the
limits are pushed further and further out,
maximizing margins and increasing the
product’s life and reliability.
OTHER USES FOR HALT CHAMBERS
HALT Chambers are the perfect tool for
returned products having failures that are
hard to expose. Returned products are
valuable because they contain a flaw.
Temperature and vibration testing in a HALT
chamber can often find these failures!
47.5
15.0
-17.5
0:00
0:17
0:35
0:53
1:10
1:28
1:46
2:03
2:21
2:39
2:56
3:14
3:32
3:49
4:07
4:25
4:42
5:00
5:18
5:35
5:53
6:11
6:28
6:46
7:04
7:21
7:39
7:57
8:14
8:32
8:50
9:07
9:25
9:43
10:00
10:18
10:36
10:53
11:11
11:29
11:46
12:04
12:22
12:39
12:57
13:15
13:32
13:50
14:08
14:25
14:43
15:01
15:18
15:36
15:54
16:11
16:29
16:47
17:04
17:22
17:40
-50.0
Example Time
HASS Profile
80.0
Temp Setpoint
HASS Profile
Vib Setpoint
42.5
5.0
-32.5
-70.0
0:00
0:01
0:02
0:04
0:05
0:06
0:08
0:09
0:10
0:12
0:13
0:14
0:16
0:17
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0:20
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0:49
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0:53
0:54
0:56
0:57
0:58
1:00
1:01
1:02
1:04
1:05
1:06
1:08
1:09
1:10
1:12
1:13
1:14
1:16
1:17
1:18
1:20
Information learned from the HALT test will
provide the product’s operating limits and it
may also provide destruct limits.
Temperature (C) / Vibration (Grms)
At this point a temporary “fix” is implemented
and the test continues on to higher levels of
stress to uncover more failures.
Examples of typical HASS profiles
Temperature (C) / Vibration (Grms)
When a failure occurs, the test is stopped and
the failure mode and stress level is recorded.
The failure is identified and documented. Root
Cause Failure Analysis is employed.
Time
›The HASS Process
T
he HASS procedure employed will vary
based on the type of product being
tested. HASS is not just a test, it is a
process – each product has its own process.
Problems uncovered may range from
manufacturing mistakes to supplier quality
issues. Root Cause Failure Analysis is
performed on all failures. If no failures occur,
the product passes – unlike HALT, HASS is a
pass/fail test.
HASS stress levels are less than those used
in HALT, but are generally more severe than
anticipated in actual service. The goal is
to use enough stress to find faults without
removing a significant amount of the
product’s life
Temp Setpoint
Vib Setpoint
This consists of running the desired HASS
process 15 to 30 times to verify that the
screen is not removing excessive life from the
product. By performing the proof of screen
successfully it is determined that the HASS
profile will not remove more than 1/15th of
the product’s life.
Common defects revealed through HASS
may include soldering problems, component
failures, incorrect components, timing
problems, IC Process change, IC Process
problem, bent IC leads, electrical tolerance,
mechanical tolerance and raw board
problems.
Testing will begin with the HASS profile
determined to be the most effective during the
Proof of Screen (POS) process. POS is a
process showing that a screen does not damage
good hardware and that the screen is effective in
finding the defects present in a product.
5
Solutions
Standard Test Chamber
Star Series™
›Galaxy 28/36/44
Integrated Pneumatic Vibration Table
& Temperature Test Chamber
HALT/HASS System
E
nvirotronics Star Galaxy™ HALT/HASS
Systems are integrated Test Chamber/
Vibration Table packages.
The surface mounting areas of the Star Series
pneumatic random vibration tables allow
great flexibility in mounting the product or
fixturing. Our improved-efficiency pneumatic
vibrators deliver the required vibration
energy while utilizing 20% less air. This can
translate into energy cost savings.
The Envirotronics Star Galaxy chambers are
equipped with a Liquid Nitrogen (LN2) cooling
system, which provides the rapid thermal
change rates required to achieve maximum
product stress.
®
6
The Galaxy system efficiently delivers high
velocity conditioned air to the test space for
unmatched temperature cycling performance.
Our adjustable air flow package allows the
user to redirect and concentrate airflow to
the product under test for maximum product
temperature cycling stress.
Galaxy system rapid thermal change rates
are accomplished with smaller space
requirements, lower audible noise, no water
requirement, lower maintenance costs and
greater efficiency than a typical refrigeration
system.
Envirotronics’ unique control system gives
the user the flexibility to control via one
accelerometer or any combination of four
accelerometers. The “brains” of the Galaxy
System is the powerful StarView Software.
Envirotronics’ exclusive diagnostic and
debugging Component Control Option
is available to enhance each of the Galaxy
models.
Option
Expanded Flexibility
Star Series™
›Component Control
Diagnostic/Debugging Option
for the Galaxy HALT/HASS Systems
D
uring HALT testing, test engineers
must perform temperature step stress
tests on products until failures occur.
Certain components may limit the engineer’s
ability to test beyond a temperature extreme.
Envirotronics is the first HALT chamber
manufacturer to successfully provide
customers with a unique diagnostic
component control feature that keeps
components at ambient while stepping
temperature.
The Component Control feature includes a
separate controller and thermocouple. With
staged heating and a proportional control
valve, Component Control provides accurate
temperature control to allow testing to
continue beyond normal product limitations.
Flexible ducting allows this optional feature to
be utilized on a wide variety of products.
With the Envirotronics’ dynamic Component
Control feature, you can keep these limiting
components at an ambient temperature in
order to continue temperature stress step
testing beyond the point where testing would
normally cease.
The component control option provides
you with a “second chamber” using its own
controller, thermocouple, heaters and cooling system. We typically locate the “second
chamber” on top of your HALT system.
The small component control duct can keep components
like power supplies at ambient while you step hot or cold –
keeping the UUT running when it would normally fail.
®
7
Solutions
Standard Test Chamber
Star Series™
›Star Plus System 28/36/44
Pneumatic Vibration Table
& Temperature Test Chamber
HALT/HASS System
T
he Envirotronics AGREE-style chamber
has been the chamber of choice for
HASS/HALT testing for years due
to its unsurpassed reliability and superior
performance characteristics.
The Star Plus chambers are equipped with
an LN2 cooling system. This system, used
in conjuction with the modulating valve and
directed air flow to the product, provides
the rapid thermal change rates required to
achieve maximum product stress with smaller
space requirements, lower audible noise, no
water requirement, and lower maintenance
costs than a typical mechanical refrigeration
system.
®
8
The chamber enclosure is insulated with
sound dampening material to keep operating
noise levels of the vibration equipment well
below 76 dBa. Access to the chamber is
through the large, full-access front and rear
doors.
The vibration table featured in the Star Plus
System is a state-of-the-art, six degree-offreedom (6DoF) tri-axial pneumatic vibration
table. A benefit of its patented unique
proprietary construction, this vibration table
has one of the most consistent acceleration
levels per unit area of any table presently on
the market.
Due to ease with which the table can be
moved, the two main components of the
Star Plus System can be used independently
from one another. The Star System’s AGREE
chamber can be used in one test application
while the Star vibration table can be used as
a stand alone unit in another application. The
Star Plus System can almost be considered
two test systems in one.
Vibration is controlled via Envirotronics’
StarVIEW software.
Solutions
Standard Equipment
Star Series™
›Star 28/36/44
Pneumatic Vibration Table
T
he heart of the Star Plus System is the
Star pneumatic vibration table which
produces quasi-random, six degreeof-freedom (6DoF), six axis, three linear (X,
Y, Z) and three angular (roll, pitch and yaw)
vibration accelerations in the frequency range
of 20 Hz to 10 kHz. The table can deliver
axis- specific vibration levels in a range from
2 gRMS to greater than *60 gRMS.
Due to its patented unique proprietary
construction, this vibration table produces
very consistent acceleration levels per unit
area. The benefit of this is that multiple
products tested on the table will all receive
almost identical vibration forces, regardless
of where they are mounted to the table. This
is not true of most other vibration tables.
Table acceleration level can be monitored and
controlled via a tri-axial accelerometer block
(X, Y and Z axis) or via single Z-axis control.
Use of tri-axial control/monitoring provides a
much more accurate indication of the overall
vibration levels your product is experiencing,
compared to the Z-axis-only control used by
some manufacturers.
Due to ease with which the table can be
moved, the table can be used independently
from the chamber.
*Specifications for export models may vary.
The Star Series tables are equipped with an
Airfloat™ pneumatic glide system. The table
virtually floats when the pneumatic glide is
activated, making it very easy to maneuver the
table in and out of the chamber. Raising and
lowering the table is so easy you can literally
do it with one finger!
®
9
Control
Powerful Intuitive
›StarView Software
Temperature and Vibration
Control and Analysis
S
tarVIEW is a user-friendly Microsoft
Windows™-based operating system
that provides easy “point and click”
program writing. The test profile is drawn
on a graph as the program is written,
allowing the user to check for errors as work
progresses. Ideal for creating custom HALT
tests and HASS Profiles.
Test Chamber Control
The StarVIEW software works in conjunction
with a Watlow F4 chamber controller to
monitor the air temperature and product
temperature. Used to monitor HALT Hot/
Cold Stress Step Test . Fourteen additional
thermocouples and Thermocouple Patch
Bridge are included with the Star Galaxy
Deluxe and Premier Models.
®
10
Vibration Table Control
Auto Spectrum
The StarVIEW software also controls the
repetitive shock shaker table. The vibration
gRMS level can be driven by the X, Y or
Z-axis; or by an average of the three values.
Used to monitor HALT Vibration Stress Step
Test. The unique StarView Control Software
allows you to control from a single axis or
from an average of multiple axes. Star Galaxy
Deluxe and Premier models include one
additional four-channel vibration system
input module with cables (customer to supply
additional accelerometers).
The vibration waveform is captured and the
fast Fourier transform applied, resulting in the
PSD graph which shows where the vibration
energy lies in the spectrum. The resonant
frequency of the Star Galaxy vibration table is
tuned to the optimal frequency range for small
electronics components, typically between
900 and 2600 Hz.
Vibration Waveform
A histogram of the acceleration vs. time
shows the actual vibration g-levels that were
reached on the table during that period. Peak
spikes as high as 10X the indicated g-level
can be shown in the histogram.
Solutions
Standard Test Chamber
›AGREE - Style
Fast Thermal Change Rate
Combined Temperature/Vibration
Test Chambers
A
vailable in standard sizes ranging from
12 to 110 cubic feet (400 L to 3100 L),
the EV Series AGREE-Style test chambers
can accommodate electrodynamic, repetitive
shock and mechanical vibration systems and/or
roll-in product carts. These chambers can also
be used as standard reach-in style chambers
with the use of a floor plug.
These chambers are designed for rapid
temperature change rates. Mechanical
refrigeration and LN2 cooling systems are
available to achieve the type of performance
you require. All systems are high pressure
leak tested and operationally tested to
performance specifications prior to shipment.
Standard Features
• Cable slot and stainless steel access port
with plugs
• Diaphragm and frame assembly, shaker to
chamber interface
• Dual air circulation system with solid
stainless steel jack shafts
• Automatic programming with linking and
looping of individual programs
• Digital indication of set-point and
temperature
• Type “T” thermocouple sensor
• RS232 and RS422 digital communications
• Event or alarm outputs
• Guaranteed soak and automatic hold
EV & EVH Temperature change rates*
No Load Maximum
Model Volume Thermal Change Rate
EV12
EV 37
EV 53
EV 70
EV 82
EV 110
400 L
1000 L
1500 L
2000 L
2300 L
3100L
10˚C/min.
20˚C/min.
20˚C/min.
20˚C/min.
20˚C/min.
20˚C/min.
*Specifications for export models may vary.
In this photo a Star 44 pneumatic vibration
table is mated with an EV 70 test chamber
®
11
Solution
We’ll find you a
O
ur slogan, “we’ll find you a Solution”
says it all about what we do here at
Envirotronics.
We find solutions for our customers’
environmental test chamber requirements
through innovative and intelligent
design, quality customer service, and our
commitment to excellence.
The images shown here represent a sample
of the equipment solutions we provide for
our customers. We would be delighted to
discuss your test chamber requirements and
how Envirotronics can provide a successful
solution for you.
Let Envirotronics find a solution for you!
Salt Spray
and Corrosion
Test Chambers
Solar Panel and Photovoltaic Module
Test Chambers
Hydraulic Cement and Concrete
Moist Cabinet Curing Chamber
Temperature and Temperature/Humidity
Test Chambers
Altitude and Altitude/Humidity
Test Chambers
Solid Construction and Modular Panel Construction
Walk-In and Drive-In Test Chambers
Mini- and Benchtop Temperature and
Temperature/Humidity Test Chambers
Thermal Shock Test Chambers
AGREE-Style
Test Chambers
Environmental Stress Screen
Test Chambers
Pneumatic Vibration
Tables
Custom Designed and Manufactured
Test Chambers
Pharmaceutical
Stability Chambers
Sand and Dust
Test Chambers
Complete HALT/HASS
Test Systems
ENV 0109 HLT
®
®
3881 N. Greenbrooke SE • Grand Rapids, MI USA 49512
Tel (800) 368-4768 • (616) 554-5020 Email sales@envirotronics.com
Fax (800) 791-7237 • (616) 554-5021 Web www.envirotronics.com