Vibration Isolation – A Simple, Versatile Solution
When doing HALT, you occasionally get into a test that requires subassemblies or portions of the functional test equipment to be isolated from the vibration stresses the product is experiencing, but also requires those assemblies to be physically close to the unit under test. Since you can’t simply put long wires on them and put them outside of the chamber, you need to get a little clever and employ some vibration isolation. In the lab at ESPEC Qualmark, we run into this often, and on a wide variety of product configurations. The attached video shows some photos of the solution we’ve employed. A similar concept may work well for you.
Many of the ESPEC Qualmark systems have the option of locating the table at two different heights in the chamber. In the Typhoon 3 in the lab we use the lower position, leaving the threaded holes that hold the table skirt in the upper position unused. We used these holes to secure a rail of 1” x 1” 80/20 extrusion to each wall of the chamber. Now, when we need isolation, we just secure a long piece of 1” x 2” extrusion to these rails, giving us a ‘bridge’ over the table. Once this bridge is in place, any kind of hardware you can think up can be secured to it, giving you a place to mount isolated assemblies as close to the product as you need to. If you don’t have the threaded holes available in the chamber to use a rail, you can do the same thing by supporting the bridge on the 1” wide table skirt bracket that surrounds the table (see the last photo in the video).
Feel free to tell us about any handy tricks you’ve used in HALT to make your testing more effective. And remember – If it isn’t broken, you’re not done yet!