HALT To Increase Product Reliability
HALT has become industry-accepted and an essential step in meeting demands for high product reliability and quality. While HALT and HASS are not typically validation tests, their value lies in incrementally stressing the product up to the point of operational fault or to destructive failure. The objective being to find latent design defects prior to validation testing, and manufacturing defects before shipping. By discovering design flaws before an item is in full production, manufacturers save significant time and costs associated with test and validation, warranty replacement, and product liability litigation.
Qualitative Data Extends Product Life
HALT is a qualitative reliability assessment that points to areas of product improvements, which when incorporated in the design can result is longer useful lifetimes and ultimately greater reliability.
Accelerated Stresses Precipitate Latent Defects Quickly
Time or cycle dependent failure modes can be revealed in an efficient manner by increasing the stress amplitude. The incremental step increase of applied stresses can quickly detects outliers in the sample distribution and hint to greater issues underlying the manufactured population.
Choose The Optimal Test for Your Product
Based on design failure mode and effect analysis (DFMEA), the most applicable and effective stress types and tests can be specified. At Elite, we provide a wide range of tests, equipment, and stress environments to uniquely match the test to the failure mechanism and quickly find potential issues.
HALT Testing At Elite
HALT is generally associated with a specific type of test equipment and environment that includes a 6-Axis Repetitive Shock (RS) vibration with hot and cold temperature exposure. At Elite, we have a 6-Axis RS HALT test machine. We also have other equipment that can apply vibration, shock, temperature, humidity, and other single or combined environment to optimally match the test to the product and its application.
Which test is best for your application?
Contact the experts at Elite and choose the optimal approach.
6-Axis Vibration With Thermal Stress
Elite’s HALT chamber is a Thermotron AST-35 which provides 6-axis repetitive shock quasi-random vibration with fatigue energy ranging 100Hz-10,000Hz. It is configured with a liquid nitrogen supply an 96kW heating systems to product separate or combined temp-vibration conditions of -100C to +100C, and up to 60Grms.
The temperature conditions at the test item are uniquely controlled by directing hot/cold air through flexible ducts and toward specific locations on the product. This feature enables thermal shock stress at up to 40-60C/minute.
Vibration is produced on a repetitive shock resonant table. The table is spring mounted at the edges and configured with a nine (9) pneumatically driven impact hammers that strike the underside of the table directed upwards. The cyclic hammer impacts and dynamic response of the table and springs generate a quasi-random vibration excitation to the test item through its mounting fixture.
The hammer strike direction, articulation of the table, and resonant response produces nearly equivalent vibration energy in the X, Y, and Z-axis of motion. There is also rotational acceleration around the X/Y/Z axes, which produces a pitch, roll, and yaw component of stress. One of the key benefits of HALT vibration is the simultaneous application of fatigue energy in each of these 6 motions.
HALT typically does not reveal a statistically structured reliability assessment such as MTBF or a Reliability-Confidence Interval metric. Physics-of-failure stress vs. cycle models that correlate to life are not suitably robust for most processes considered for common HALT machines. Still, the objective of this test is to reveal potential design and quality issues that when improved upon will increase the life and reliability of the product.
Electro-Dynamic Vibration Step-Stress Testing
Qualitative accelerated life testing can also be performed using electro-dynamic vibration tables for mechanical fatigue along with vibe-table-mounted thermal chamber.
This approach has the advantage of using an electrodynamic system which can be driven at a specified vibration spectral energy that matches the end use application. The vibration profile can also be step-wise increased in a uniform cross-spectrum manner to accelerate fatigue by “shifting left” on the stress-cycle (S-N) curve.
Elite and our vibration partner Vibration Research Corporation (VRC) are also available to support the Kurtosion® test algorithm at Elite. This unique vibration control feature allows the vibration table to increase peaks Gs of the vibration amplitude. This means that for a typical vibration tests with a nominal 10Grms vibration, the control system will drive a 3-sigma (3 x Rms) peak acceleration of 30Gs. With the Kurtosion control algorithm the vibration peak accelerations are driven to much higher amplitudes, which is more representative of a random vibration environment application and also more in line with a repetitive-shock vibration test from a HALT machine.
All Elite vibration tables can be fitted with a temperature hood enclosure to include thermal stress in combination with vibration.
HALT Chamber Capabilities
Chamber Specifications
- -100C to +200C (-148F to +302F)
- +60C per minute product temperature ramp rates (heating or cooling)
- 36″ x 36″ Vibration Table, 480lbs total weight capacity for test item & fixture
- Workspace Dimensions 42″W x 42″D x 40″H
- Vibration Frequency Range: 2Hz-10kHz
- Vibration Level: Up to 50Grms
- Two 3″x8″ access ports, Three 20″x20″ viewing window
HALT/HASS Quick Links
- HALT Chamber Facilities Page
- Elite’s Spring 2022 HALT Testing Webinar
- Elite’s HALT/HASS Testing Blog
Ready to Connect with an Elite Expert?
Our testing experts are available to answer your questions about our capabilities. Connect with us to discuss your requirements.
Our HALT/HASS Specialists
You need to know your product will reliably operate in the long term. HALT and HASS testing gives insight into a product’s expected life. Elite’s HALT and HASS testing team brings their experience and know-how to your product.
Steve Laya
Sales and Marketing Manager
Eric Lindberg
Environmental Team Leader / Dynamics
John Lindberg
Environmental Stress Lab Manager
