Stress Screening Systems

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Stress Screening Systems
›ESS Systems
Rapid Temperature Change Rates
For Environmental Stress Screening Applications
www.envirotronics.com
Stress Screening
Environmental
T
oday, we take problem-free operation
of the “every-day” products we use
for granted.
In critical situations, we must be able to
depend on safety systems functioning under
any and all conditions.
The testing of individual components,
subassemblies and finished products
ensures the reliability of the products and
systems we rely on every day. Producers
apply environmental stress screening to
ensure that these products and systems do
not fail in the field.
In simple terms, environmental stress
screening is any process that induces
latent product flaws through the application
of highly accelerated or exaggerated
environmental stimulation.
Life cycle graph of electronic components
A = ESS moves these failures from field to factory
F = Failures t = Time 1 = Infant mortality
2 = Operational lifetime
3 = Wear out phase
The goal of ESS (environmental stress
screening) is to dramatically reduce
product failures in the field. This is
accomplished by precipitating and
detecting flaws in design and materials in
the prototype and production phases.
HALT (Highly Accelerated Life Test) is
performed in the design and prototyping
stage to expose latent flaws in materials and
design, and to determine the destruct limits of
a product. From information gathered in the
HALT process, a HASS (Highly Accelerated
Stress Screen) profile is developed to further
precipitate latent defects in materials and
production processes. HASS is a form of
ESS. HALT and HASS practitioners typically
utilize a combination of thermal cycling and
vibration to induce failures.
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Changing temperature according to IEC 60068-2-14, Test Nb
T = Temperature
Tu = Ambient temperature
T1 = Low temperature
Z = N-cycles
T2 = High temperature t = Time
Effectiveness
Test Screen
Rapid thermal change rates create
mechanical and thermal stress in the
product. Stress Screening (ESS) is
employed in the production phase. The
tailored application of ESS rapid thermal
cycling has proven to be the most effective
method of precipitating failure without
significantly affecting the expected “life” of
the product. This means that ESS is a pass/
fail production process for screening out
defective components or assemblies.
Envirotronics test chambers can simulate the
temperature ranges and thermal change rates
required for your product reliability program.
Due to the wide variety of products being tested,
today’s customer requirements dictate that
several temperature ranges, thermal change
rate capabilities and workspace dimensions be
offered. Envirotronics will manufacture an ESS
chamber to meet your specific environmental
stress screening needs.
You can rely on Envirotronics to meet your
reliability program’s needs.
Effectiveness of thermal cycles and high temperature storage
for preconditioning of circuit boards
A = Effectiveness
B = Thermal cycles C = High temperature storage
Z = Cycles
t = Time
Δt = increased temperature to maximum temperature for use
Effectiveness of different
environmental screening
methods
Temperature cycling
Random vibration
High temperature
Electrical stress
Thermal shock
Sine vibration, fixed frequency
Low temperature
Sine vibration, sweep frequency
Combined environmental
Mechanical shock
Humidity
Acceleration
Altitude
A = Weighted Rank
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Solutions
Standard Test Chamber
›Reach-In Style
Fast Thermal Change Rate High-Low Temperature
and Temperature/Humidity Test Chambers for
Environmental Stress Screening Applications
T
hese sturdy, single-unit construction
reach-in-style test chambers are
available in a range of standard sizes
and can deliver testing environments as
aggressive as required for your ESS needs.
Our ET Series chambers are temperature only
test chambers while our EH Series offers both
temperature and humidity conditions. If your
requirements fall outside of the realm of our
standard sizes, ET and EH chambers can be
customized to meet your specific needs in
terms of size, airflow or performance.
ET and EH chambers are loaded with standard
features that ensure the durability and
reliability of your test chamber for years to
come and that enhance its ease-of-use. Your
test profiles can be pre-programmed into
the controller, so running your test can be as
simple as pressing a button.
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ET and EH Series chambers are available with
either horizontal or vertical airflow and can be
equipped with an adjustable rack for holding
your test specimens.
Temperature Range:
-73˚C to +177˚C
Control Accuracy: 0.1 - 1.1˚C
Humidity Range:
20% to 95% ±1-3% relative humidity.
Extended ranges available.
ET & EH Temperature change rates
No Load Maximum
Model Volume Thermal Change Rate
ET 8
ET 18
ET 27
ET 40
ET 64
300 L
500 L
750 L
1150 L
1800 L
5˚C/min.
10˚C/min.
15˚C/min.
15˚C/min.
20˚C/min.
Solutions
Custom Test Chamber
›Cart-Based Style
Fast Thermal Change Rate High-Low Temperature
and Temperature/Humidity Test Chambers for
Environmental Stress Screening Applications
T
he Envirotronics ESS line of
chambers are designed to maximize
the testing capabilities for 19” rack
mountable equipment. It was designed with
right-to-left cross-chamber airflow to work
with customer product by moving the air
in the same direction as current customercompleted chassis designs. This helps to
eliminate temperature gradients between
upper and lower test tiers found in typical
environmental chamber configurations. All
chassis are exposed to identical temperature
swings, changes and ramp rates.
We can also offer a special system with
vertical and horizontal airflow.
Today’s customer demands also require several
different temperature ranges as well as varied
thermal change rate capabilities. Envirotronics
will equip your system with single-stage,
cascade, twin-screw, LN2 boost, or LN2 cooled
refrigeration systems. Our control systems
can utilize Quick Draw (chamber control
based on product temperature) to ensure that
your product reaches set point as quickly as
possible to reduce cycle times.
Due to today’s customer demands and
the wide variety of products being tested,
Envirotronics can design your system to
feature either horizontal or vertical air flow.
We have built our reputation on finding the right
test chamber solutions for our customers. We
will manufacture an ESS chamber to meet your
specific environmental stress screening needs.
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Solutions
Highly Accelerated
Stress Screen
›AGREE - Style
Fast Thermal Change Rate
Combined Temperature/Vibration
Test Chambers
A
vailable in standard sizes ranging from
12 to 82 cubic feet (400 L to 2300 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 a standard reach-in style
chamber 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.
In this photo a Star 44 pneumatic vibration
table is mated with an EV 70 test chamber
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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
• LN2 cooling systems optional
• 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
400 L
1000 L
1500 L
2000 L
2300 L
10˚C/min.
20˚C/min.
20˚C/min.
20˚C/min.
20˚C/min.
Solutions
Specialty Airflow
The following airflow patterns are typical of ESS Testing:
Horizontal Airflow
High velocity conditioned air is drawn
from right-to-left across the unit(s)
under test.
The horizontal airflow pattern is
commonly used in testing roll-in carts
of electronic equipment.
Interior of an ET-HAF model test chamber
AGREE-Style Airflow
Vertical Airflow
High velocity conditioned air is drawn
from bottom-to-top through the unit(s)
under test.
The vertical airflow pattern is commonly
used to test PC boards mounted in an
open card cage.
High velocity conditioned air is drawn up
through the middle of the workspace and
returned along the sidewalls.
The AGREE-style airflow pattern is
commonly used in conjunction with a
vibration table for HASS testing.
Interior of an ET-VAF model test chamber
Interior of a Star 44 HALT/HASS test system
BLOWER
WHEELS
BLOWER
WHEELS
BLOWER
WHEELS
REFRIGERATION
HEATER
HEATER
WORKSPACE
R E F R I G E R AT I O N
WORKSPACE
HEATER
SHELF
REFRIG.
WORKSPACE
VIEW FROM FRONT
(DOOR OPENING)
FRONT or SIDE VIEW
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Solutions
Standard
and Custom
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W
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.
Temperature and Temperature/Humidity
Test Chambers
Environmental Stress Screen
Test Chambers
Let Envirotronics find a solution for you!
Altitude and Altitude/Humidity
Test Chambers
Salt Spray
and Corrosion
Test Chambers
Mini and Benchtop Temperature and
Temperature/Humidity Test Chambers
Solar Panel and Photovoltaic Module
Test Chambers
AGREE-Style
Test Chambers
Thermal Shock Test Chambers
Pneumatic Vibration
Tables
Solid Construction and Modular Panel Construction
Walk-In and Drive-In Test Chambers
Custom Designed and Manufactured
Test Chambers
Hydraulic Cement and Concrete
Moist Cabinet Curing Chamber
Complete HALT/HASS
Test Systems
Sand and Dust
Test Chambers
Pharmaceutical
Stability Chambers
Complete Test Chamber
Service, Calibrations & Retrofit
(updated 4/2014)
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Weiss Envirotronics, Inc.
Environmental Test Chambers
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