What materials should be used for sound insulation?
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We have recently developed a product equipped with a micro motor, featuring a rotation speed of 2000–2500 rad/min and a noise level of 85 decibels. The technical requirement is no more than 50 decibels; however, after contacting the motor manufacturer, it was determined that the noise level cannot be reduced at such high speeds. It has been decided to use foam plastic for noise reduction. I have very little experience with foam plastics; I’m asking the guys what type of foam plastic and what thickness can be used to reduce noise levels? Thank you.
A porous material should do, I guess. There are many types of foam materials; for example, EPS expanded polystyrene. I have worked with this material before, and I had no idea it could be used for sound insulation. There are also polyurethane foam materials, which have a certain sound-insulating effect. However, if these foam materials are used, it is likely to have a significant impact on the heat dissipation of your equipment. I think a soundproof enclosure should be installed on the device after it has been installed.
Flame-retardant sound-absorbing materials include organic and inorganic fibers, polyurethane foam, glass fibers, glass wool, and other such materials. You can study them and then choose one. I recommend one product: polyetherimide. Application Areas Polyetherimide boasts excellent overall performance characteristics, and is effectively used in industries such as electronics, electrical machinery, and aviation. It is also employed as a substitute for metals in traditional products and items used in daily life. In the electrical and electronics industry, components made from polyetherimide materials are widely used, including connectors with high strength and dimensional stability, housings for standard and miniature relays, circuit boards, coils, flexible circuits, mirrors, and high-precision fiber optic components. It is particularly noteworthy that using it to replace metals in the manufacture of fiber optic connectors allows for the optimization of the component structure, simplifies the manufacturing and assembly processes, and maintains more precise dimensions, thereby reducing the cost of the final product by approximately 40%. The impact-resistant material Ultem 1613 is used to manufacture various aircraft components, such as portholes, nose parts, seat backs, interior panels, door covers, and various items for passengers. Composites made of PEI and carbon fiber have been used in the structures of various components of the latest helicopters. Thanks to its excellent mechanical properties, heat resistance, and chemical resistance, PEI is used in the automotive industry for manufacturing high-temperature connectors, high-power headlights and indicator lights, sensors for controlling the external temperature of the vehicle cabin (air conditioning temperature sensors), and sensors for controlling the temperature of the air and fuel mixture (effective combustion temperature sensors). Furthermore, PEI can also be used for vacuum pump impellers resistant to high-temperature lubricant erosion, ground glass joints (sealing joints) in distillers operating at 180°C, and mirrors in unlit anti-fog lights.
Many types of foam plastics can provide sound insulation. Materials such as foamed PVC, PU, and sponge are also available
It is best to use closed-cell foam materials (styrene, polyurethane); open-cell foam (foam rubber) yields poorer results.
It is recommended to use polyurethane material; it is best not to have any pores formed during foaming, as this improves the sound insulation performance.
With the current shortage of Earth’s resources, there is a global call for resource conservation and for scientific innovation through the use of new energy sources. As a result, nanomaterials have become an area of interest worldwide. It is said that nanomaterials possess many little-known functions; the main functions that have been identified so far include antibacterial and antifungal properties, corrosion and odor prevention, protection against infrared and ultraviolet rays, as well as heat insulation. The sound-insulating property has not yet been confirmed; you could consult relevant nanomaterials to see if it is possible to test whether this function exists
Polyurethane blowing agents can provide sound insulation; Eva-type expansion sheets can also be used, which are positioned at room temperature and expand when heated
Regarding noise reduction, two aspects need to be considered. 1. Sound absorption: It is recommended to use BASF’s BASOTECT material, which offers excellent sound absorption properties, as well as resistance to high temperatures and flame retardancy; it was used in the Water Cube. Apologies, but it is also a product of our company; it is used in the Airbus A380 as well as in Tsinghua University’s noise research laboratory, and its applications are widespread. 2. Sound insulation: Many suggestions have already been given on this topic, so I won’t go into too much detail
It is best to use closed-cell foam materials (styrene, polyurethane); open-cell foam (foam rubber) gives poorer results