By Joyce Laird, Contributing Editor
Vibration damping reduces noise in applications ranging from appliances, vehicles and ships to all types of industrial machinery. By dissipating vibrational energy from substrates into other forms of energy it serves to reduce both noise and vibration resonance in the end product.
Noise, vibration and harshness (NVH) can adversely affect users’ overall comfort with machinery. Reducing NVH improves or eliminates unwanted noise. Reducing vibrational resonance can also enhance the life of the equipment.
Typically, vibration damping materials include heavy pads or sheets made of asphaltic or polyurethane membranes, epoxies or rubber materials. While the sound damping sheets do continue to reduce in size slightly with each subsequent generation, the installation process still requires them to be pre-cut, then manually installed.
Where is the Evolution of Damping Headed?
Chemist Justin Gimbal and Raymond Somich, Market Manager, both with Dow Coating Materials, have worked together closely on developing new alternative damping materials. Gimbal explains that this new technology is based on waterborne acrylic polymer technology and is called Liquid-Applied Sound Damping (LASD). In lieu of using large sheets of sound damping materials that need to be cut and manually applied, manufacturers may now use modernized assembly processes to apply this sprayable, liquid coating alternative. The coating, typically applied in thicknesses of 2 to 4 millimeters, is versatile, easy to apply, and offers excellent noise/vibration reduction with potentially 35% lower weight compared to alternative technologies.
“The ability to customize damping profiles for a range of performance needs provides manufacturers with flexibility. This helps reduce the material cost and overall weight of the finished product, as paint applicators may apply as much or as little coating as needed. LASD Technology also eliminates the complexities surrounding manual application, inventory management and storage space needed for common materials like bitumen pads. Because LASD coatings are waterborne, they help reduce VOC emissions and contribute to worker safety,” Somich adds.
“Our challenge was to address how to take this product beyond being just another coating and add more in terms of functionality,” Gimbal says. “The industry wanted coatings to do more in the area of sound and vibration elimination.”
Any application that can benefit from sound management and reduced NVH can benefit from LASD Technology. LASD coatings can be used successfully in applications as diverse as vehicles, railcars and ships; agriculture and construction equipment; appliances; HVAC and air conditioning units; and roofs and floors. Even spaces including elevator shafts and boiler rooms can benefit from the noise reduction benefits offered by LASD Technology.
“LASD Technology is well-suited to the growing manufacturing trend toward modern computer-controlled robotics,” Somich explains. “This provides an alternative that fits high volume, automated applications. At the same time, users can also apply this using a spray gun or brush. So smaller companies don’t have to suddenly jump into fully automated assembly lines. The material fits into any scenario.”
Manufacturers can now simultaneously manage different tasks – like LASD coating spray application and curing at one station in a factory for reduced production times. “The application versatility also allows for easy application in difficult-to-reach spots or thicker coating applications in areas with higher vibrational energy,” Gimbal said.
Somich adds that a number of studies currently being conducted are focused on “fatigue model” in machines. “While we have not done any of that research ourselves, we are starting to see that this is the reason more manufacturers are moving to our type of damping technology. Even though that was not why Dow originally developed the material, we are seeing a lot of new areas where it is bringing unique benefits beyond simple sound damping. People are starting to look at the overall life costs of a piece of machinery and how this material can extend the service life of that equipment substantially.”
Is it right for your application?
The Dow research and development team works closely with customers to determine the performance requirements and specifications needed in an LASD coating for any particular application. Damping can be determined by assessing the Composite Loss Factor (CLF), a measure of the sound damping ability of the composite (coated substrate). Factors that influence CLF, such as coating weight and thickness, the types and levels of polymers and fillers used, and the way these polymers and fillers interact, tare tested o refine sound damping performance specifications.
“As an organization, we feel that we have just started working on the tip of the iceberg in terms of both different types of applications and evolving materials for those applications,” said Somich . “We are challenging engineers in all industries to rethink how they’ve been doing this and what they need to make better end equipment. We are very excited about this area and are ready to work closely with end users to match the exact product technology to their specific needs.”
Dow Coating Materials