In this new column in The PCB Magazine, NTS Baltimore General Manager Keith Sellers offers a brief review of the common military testing documents that guide PCBs, printed circuit assemblies, and some electrical components for the critical and often complicated defense sector.
NTS is pleased to announce that our Longmont, Colorado facility is now offering environmental testing starting in September, 2016. In addition to our current world-class EMI capabilities we can now provide:
- Electro Dynamic Shakers:
Sine, Random, Classical Shock
- Shock Testing:
Aircraft, Transportation, Bump
- Constant Acceleration, Crash Safety
- Thermal Cycling
- Temperature Shock
Whether you need to qualify for MIL-STD 810, MIL-STD 167, MIL-STD 1540 or RTCA DO-160, we can answer any questions you might have. When you are ready, our team can provide a competitively priced testing proposal and scheduling to fit your needs.
The G revision of the MIL-STD-461 standard was released in December 2015 and is available here. NTS’s Jeffrey Viel’s wrote an article for InCompliance Magazine reviewing the proposed changes which was published back in August 2015. These changes have carried into the final released standard and are worth reviewing.
A few highlights of the MIL-STD-461G standard:
- FFT receivers are now permitted for use
- Interconnecting cable routing now specified for floor standing equipment
- Test method CS106 has been removed
- Test method CS114 system check updates
- The addition of test method CS117, conducted susceptibility, lightning induced transients, cables and power leads
- The addition of test method CS118, personnel borne electrostatic discharge
- Test methods RE102 and RS103 technical updates
Contact NTS today to discuss your next MIL-STD-461 test program.
Environmental testing has been a major component of NTS services since our founding in 1961. Military and commercial standards such as MIL-STD-810 and RTCA/DO-160 include sections for thermal shock, icing, freezing rain, and hail impact.
Thermal shock testing lies at the most severe end of the spectrum of temperature tests performed by NTS. Thermal shock refers to a very high rate of temperature change and is generally conducted on aircraft components, military hardware and electronics designed to withstand harsh environments.
Because almost all products are subject to shipping, this test may be appropriate for any part that will have to withstand an abrupt temperature change in a short period of time, such as a transition from environmentally controlled storage to the varying environments encountered during transport.
Air-to-air thermal shock testing is the most common test performed at our laboratories. It is conducted by moving the test article from one extreme temperature to another on a mechanical conveyor or elevator, depending upon the orientation of the chambers. Fully enclosed thermal shock test chambers keep the equipment stationary while the chamber temperature cycles.
For very large items that cannot be moved by an in-chamber elevator, NTS can provide fixtures and the right setup to meet applicable test specification requirements while assuring the safety of the test item. In one such case, NTS engineers in Boxborough, MA were faced with the challenge of performing icing testing a on a tall telescoping antenna while it was under operation. A custom 23’ x 7’ 7” chamber with temperature controls was built to accommodate this extreme test.
Other examples of specialty thermal shock testing include a liquid-to-liquid system in which a basket is utilized to mechanically transfer a test article from one vat to another for a higher transfer rate of greater thermal energy. NTS also performs cryogenic testing for launch vehicles, satellites, and related hardware. Two large capacity LN2 pits are available for testing that requires either simple atmospheric or highly pressurized sub-freezing temperature shock.
Give us a call today at 800-649-5289 to discuss your extreme environmental testing!
Fungus testing for MIL-STD-810 Applications
On September 17th, NTS conducted a one-hour webinar titled “EMI/EMC Requirements for Navy Shipboard and Submarine Applications in accordance with MIL-STD-461F”. Led by NTS Director of Technology, EMI / EMC, Jeff Viel, the webinar covered the EMI/EMC verification requirements for Navy Shipboard equipment. Common design techniques used to ensure electromagnetic compliance to the control requirements of MIL-STD-461F were discussed.
Solar radiation can be very damaging to materials and equipment stored and used outdoors. MIL-STD810, Method 505 is designed to evaluate materials as they are exposed to the radiation and heating effects of direct exposure to sunlight. NTS has developed and is now operating state of the art facilities in Tempe, Arizona for this testing.
Examples of these test materials include:
- Glazing and transparent armor
- Carbon fiber, Kevlar and other armor
- Plastics and elastomers
- Electrical and electronic components
- Portable communication equipment
- UAV and control equipment
- Alternative power equipment
- Any material used in outdoor applications
Proprietary radiation sources provide the spectral content and irradiance to the exacting tolerances required by the standard. In addition to the radiation requirements, the standard also requires that temperature and wind speed also be controlled to tight tolerances.
NTS test cells are purpose built to provide the correct environment to replicate the conditions seen in the field as required by the MIL Standard. NTS radiation sources are engineered to provide the correct spectral content, which includes UVA, UVB, visible, and infrared wavelengths.
Procedure 1 testing (Heating Effects)
- Used to investigate response temperatures when material is exposed in realistically hot climates, and is expected to perform without degradation during and after exposure
- Used to generate maximum response temperature of the test item, for use in Procedure 2 solar testing
- It is preferable to use the solar radiation test rather than a temperature-only test because the effects of differential heating caused by solar radiation on material are unknown
Procedure 2 testing (Actinic Effects)
- Used to investigate the effects on materiel of long exposure to sunshine
- An accelerated designed to reduce the time to reproduce the cumulative effects of long periods of exposure
- Chambers designed to provide enough cooling air to prevent the test item from exceeding peak temperatures that would be attained under natural conditions
NTS operates several test cells dedicated to solar radiation testing with internal volumes of 1000 cubic feet, which allow economical testing of larger test articles. Multiple radiation sources are available to provide the required heat and radiation in a configuration that allows the test subjects to be irradiated from any angle. Uniformity of the radiation across the test article is controlled within specification limits.
Current capabilities include:
- Procedure 1 system – 4′ x 6′ irradiated area
- Procedure 2 system – 4′ x 6′ irradiated area with air cooled Mercury-doped Metal Halide lamps
- Procedure 2 system – 6′ x 6′ irradiated area with air cooled Mercury-doped Metal Halide lamps
NTS engineers have designed a user interface system based on LABVIEW software that provides full control of all required parameters for testing. This proprietary software monitors spectral content, irradiance, airspeed, test article and chamber temperature and other selectable parameters and displays the data in real-time. All parameters are plotted to graphical for-mat for review and inclusion in the test report. The system auto-mates the setup and calibration, resulting in better accuracy and lower cost to the customer. All instrumentation is calibrated by an accredited laboratory, and is traceable to NIST. Full equipment lists with calibration traceability are provided with the subsequent test report.
Advantages of the NTS Solar Radiation test system include our ability to handle larger test articles and orientation of those test articles as required. We also offer real-time monitoring/recording of irradiance and spectral content as well as automated data processing and reporting.
For more information on how we can help with your solar testing needs please contact the experts at the Tempe lab directly, 480.966.5517 or visit our webpage for a list of additional services and accreditations.
NTS has partnered with the Equipment Reliability Institute to offer this four day course. Aimed at individuals who will need to perform, witness or specify environmental testing in accordance with MIL-STD-810. The course will cover vibration and shock methods will be covered and the course will include a tour of the NTS Fullerton, CA test facility, where the full spectrum of MIL-STD-810 testing is conducted.
Full details and course registration information can be found at the Equipment Reliability Institute’s website.