Highly accelerated stress screening
Encyclopedia
HASS Testing is a proven test method developed to find Manufacturing
/Production-process
induced defects in electronics
and electro-mechanical assemblies before those products are released to market. HASS is a powerful testing tool for improving product reliability
, reducing warranty
costs and increasing customer satisfaction
.
"After a product has undergone HALT Testing
, HASS Testing can be deployed in the production process. Once the product is made robust (through the application of HALT), the next logical step is to monitor the production processes using a technique called Highly Accelerated Stress Screening (HASS). The goal of a HASS is to induce failure modes that can be inherent or introduced in the production process. HASS have been proven to be effective in screening failures that may have gone undetected in the burn-in testing process. A product that passes normal production tests but fails in a HASS would have probably failed early after product release increasing warranty costs."
"HASS - Highly Accelerated Stress Screening: Used to improve the robustness/reliability of a product through test-fail-fix process where the applied stresses may be beyond the specified operating limits (OL) determined by HALT. This is applied to 100% of the manufactured units."
There are 2 parts to HASS Testing:
Since HASS levels are more aggressive than conventional screening tools, a POS procedure is used to establish the effectiveness in revealing production induced defects. A POS is vital to determine that the HASS stresses are capable of revealing production defects, but not so extreme as to remove significant life from the test item. Instituting HASS to screen the product is an excellent tool to maintain a high level of robustness and it will reduce the test time required to screen a product resulting in long term savings. Ongoing HASS screening assures that any weak components
or manufacturing process degradations are quickly detected and corrected. HASS is not intended to be a rigid process that has an endpoint. It is a dynamic process that may need modification or adjustment over the life of the product.
HASS Testing Benefits:
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
/Production-process
Production (economics)
In economics, production is the act of creating 'use' value or 'utility' that can satisfy a want or need. The act may or may not include factors of production other than labor...
induced defects in electronics
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
and electro-mechanical assemblies before those products are released to market. HASS is a powerful testing tool for improving product reliability
Reliability
In general, reliability is the ability of a person or system to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances.Reliability may refer to:...
, reducing warranty
Warranty
In business and legal transactions, a warranty is an assurance by one party to the other party that specific facts or conditions are true or will happen; the other party is permitted to rely on that assurance and seek some type of remedy if it is not true or followed.In real estate transactions, a...
costs and increasing customer satisfaction
Customer satisfaction
Customer satisfaction, a term frequently used in marketing, is a measure of how products and services supplied by a company meet or surpass customer expectation...
.
"After a product has undergone HALT Testing
Highly Accelerated Life Test
A highly accelerated life test , is a stress testing methodology for accelerating product reliability during the engineering development process. It is commonly applied to electronic equipment and is performed to identify and thus help resolve design weaknesses in newly-developed equipment...
, HASS Testing can be deployed in the production process. Once the product is made robust (through the application of HALT), the next logical step is to monitor the production processes using a technique called Highly Accelerated Stress Screening (HASS). The goal of a HASS is to induce failure modes that can be inherent or introduced in the production process. HASS have been proven to be effective in screening failures that may have gone undetected in the burn-in testing process. A product that passes normal production tests but fails in a HASS would have probably failed early after product release increasing warranty costs."
"HASS - Highly Accelerated Stress Screening: Used to improve the robustness/reliability of a product through test-fail-fix process where the applied stresses may be beyond the specified operating limits (OL) determined by HALT. This is applied to 100% of the manufactured units."
There are 2 parts to HASS Testing:
- HASS Development/Proof-of-screen (POS)
- HASS Production Screen.
Since HASS levels are more aggressive than conventional screening tools, a POS procedure is used to establish the effectiveness in revealing production induced defects. A POS is vital to determine that the HASS stresses are capable of revealing production defects, but not so extreme as to remove significant life from the test item. Instituting HASS to screen the product is an excellent tool to maintain a high level of robustness and it will reduce the test time required to screen a product resulting in long term savings. Ongoing HASS screening assures that any weak components
Electronic component
An electronic component is a basic electronic element and may be available in a discrete form having two or more electrical terminals . These are intended to be connected together, usually by soldering to a printed circuit board, in order to create an electronic circuit with a particular function...
or manufacturing process degradations are quickly detected and corrected. HASS is not intended to be a rigid process that has an endpoint. It is a dynamic process that may need modification or adjustment over the life of the product.
HASS Testing Benefits:
- • Assures Manufacturing process and workmanshipWorkmanshipWorkmanship is an EP by Joy Electric released exclusively as a 7" vinyl record album through Republic of Texas Recordings. Workmanship was completely written and recorded by Ronnie Martin on a Minimoog Voyager synthesizer...
integrity. - • Verifies integrity of mechanical interconnects and component tolerance compatibility.
- • Identify and preclude escape of potential early life product failures.
- • Decrease product infant mortality, and increase reliability.
- • Detect & correct design & process changes.
- • Detect & correct component variation.
- • Reduce production time & cost.
- • Increase out-of-box quality & field reliability.
- • Decrease field service & warranty costs.
- • Find Manufacturing Process Problems
- o Component Placement (pick & place roboticsRoboticsRobotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...
) - o Solder & Paste Processes
- o IC Vendor and or Process changes
- o Early Detection of Margin shifts
- o Accelerate Infant Mortality failures
- o Timing problems (that only occur under stress)
- o Assembly errors - connectors, screws/fasteners
- o Cable Routing - rubbing, pinched, solderSolderSolder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...
connection
- o Component Placement (pick & place robotics
Further reading
- "Management & Technical Guidelines for the ESS Process" IEST-RP-PR001.1, published by the Institute of Environmental Sciences and Technology.
- "Accelerated Testing" a Practitioners Guide to Accelerated and Reliability Testing, by Bryan Dodson and Harry Schwab.
- "IPC 9592A-Requirements for Power Conversion Devices for the Computer and Telecommunications Industries"
External links
- cotsjournalonline.com - COTS Journal HALT/HASS Testing Goes Beyond the Norm