Our tour of Raymarine’s Environmental Test Centre continues with a visit to the Salt Mist Room, Hot Room and Shaker Room, in the last of which products undergo shock and vibration tests
Vibration is the hidden enemy for both electronics and mechanical structures. Constant shaking across a range of frequencies can work fixings loose, fatigue wires and damage solder joints, resulting in equipment failure. NASA’s James Webb Space Telescope – originally scheduled for launch in 2011 – is still on the ground, in part due to failing vibration and acoustic testing more than once.
Naturally, vibration testing is built into the gruelling regime at Raymarine’s Environmental Test Centre. Typically, however, Raymarine’s approach goes way beyond standard IEC 60945 tests. In the aptly named Shaker Room, vertical and horizontal shakers perform swept sine and dwell tests, subjecting items to a vibration sine tone across a broad frequency range. Where a resonance is found during the sweep, testers will dwell on that frequency for two hours to check fatigue damage.
The standard test is 5Hz-100Hz, but Raymarine pushes that to 600Hz, as well as performing shock and random vibration tests informed by real-life vibration data from customers’ boats.
By the time products fetch up in the Shaker Room, they will already have taken a substantial beating. Starting with the thermal chambers and Wet Room, procedures include continual high-pressure spraying with water and leaving products in a damp, drizzly atmosphere all day: but the water ingress tests are merely beginning.
Thereafter, the Salt Mist Room exposes products to salt spray for two hours: they are then left for seven days in a warm, damp atmosphere, and this process is repeated four times, taking the test duration to 28 long days. This is supplemented with another harsh 28-day test in a warm, damp, salty atmosphere, to assess different failure mechanisms. With the first test, salt and water can leach into coatings and make them blister or lose colour, while the other examines salt crystal buildup which can make plastics crack.
…And even this isn’t enough. Subsequent IPX7 tests determine products’ ability to withstand immersion at a defined depth for a specified duration. The immersion tanks are also used to check fishfinder transducers’ performance during their test program.
And then the test centre literally turns up the heat. Products are placed inside the 55°C Hot Room for life tests, so they can be in there for months! Along similar lines, an IR (Infrared Radiation) test simulates noon sunshine to ensure that displays don’t black out and that no sunlight damage occurs to them; e.g. glow marks or buckled film inside the display panel.
Even after all of this, products still have a long way to go before being tested to Raymarine’s satisfaction…