Excessive vibration can have a significant impact on the efficiency, lifespan and safety of equipment. Continuous vibrations can cause the below issues in electronics:
– PCB board warping
– Component Loosening
– Solder joint fatigue
– Intermittent connections
– Sensor inaccuracy
In safety critical markets such as medical or automotive these problems can be catastrophic.
It is not just electronic devices that can be affected by vibrations; this issue is also common place in mechanical and machinery applications. Being able to reduce vibration in machinery is vital for protecting surrounding mechanical structures. If left untreated excessive vibrations can cause the below issues:
– Loosening of screws and bolts
– Loss of production
– Transmitted noise, which can travel throughout a building
– Damage to floors
– Malfunctions with sensitive and accurate equipment
– Operator discomfort
Using anti vibration mounts prevents these issues from happening, and they offer three main purposes:
Vibration isolation: preventing machine-generated vibration from reaching the structure.
Noise reduction: blocking structure-borne noise transmission paths.
Shock absorption: protecting equipment from external shock loads and floor-transmitted impact.
Selecting the right anti-vibration mounting is not just about reducing vibrations; it’s about enhancing performance and protecting your equipment. With so many anti vibration mounts available to choose from, understanding the key factors around your choice is crucial. The below guide will assist you with your selection.
What is an anti-vibration mount?
Also known as AV mounts or vibration isolators, they are polymer components used to absorb and dampen mechanical vibrations and shocks. They help prevent damage, reduce noise, and improve operator comfort in various mechanical or electronic systems. AV mounts are usually fixed to the bottom of the application.
Criteria for Specifying the correct anti-vibration mount
When selecting anti vibration mounts, consider the following criteria carefully:
1) Load Requirements
Each mount is designed to support a specific static and dynamic load. Overloading can cause premature failure, while under-loading may reduce isolation effectiveness. Consider the following:
– Determine the equipment weight.
– Distribute weight evenly across mounts
– Factor in dynamic forces (e.g., from motors or compressors).
In an ideal situation the area to isolate would be a perfect square shape with the weight distributed evenly across each corner. However, there are occasions where you have to eliminate the vibration across an uneven shaped object with one side of the device being heavier than the other.
For example you may have a device that weights 60kg, however the left side of the device is 40kg and the right side is 20kg. In this situation you would select 2 x one part number that could support 20kg each (40kg/2), and 2 x another part number that could support 10kg each (20kg/2).
2) Vibration Frequency
Vibration frequency is one of the most important factors when selecting an anti vibration mount. It refers to how quickly a machine vibrates and is typically measured in Hertz (Hz), or cycles per second. Every piece of rotating equipment generates vibration at a specific frequency based on its operating speed. Please see below example:
A compressor operating at 3,600 RPM produces a vibration frequency of 60 Hz.
To convert RPM to Hertz, use the following formula:
Frequency (Hz) = RPM ÷ 60
For anti-vibration mounts to isolate vibration effectively, their natural frequency must be significantly lower than the vibration frequency of the equipment. This creates an isolation zone where vibration energy is absorbed rather than transmitted to surrounding structures.
If the equipment’s vibration frequency is too close to the mount’s natural frequency, resonance can occur. Resonance amplifies vibration, increasing noise levels, accelerating component wear, and potentially causing equipment damage.
As a general rule, the operating vibration frequency should be at least 1.4 to 2 times greater than the mount’s natural frequency to achieve effective vibration isolation.
3) Load vs stiffness
– Softer mounts are better for lighter loads and lower frequencies. They offer better vibration isolation but allow greater movement.
– Harder mounts are better for heavier loads and higher frequencies. They provide less vibration isolation.
– Heavier loads compress mounts further, reducing their natural frequency and improving low-frequency isolation.
4) Understanding Static Deflection
Static deflection is the amount a mount compresses under a given static load. It is one of the most critical parameters for determining the natural frequency of a mount and, therefore, its vibration isolation performance. In general, the greater the static deflection, the lower the mount’s natural frequency and the better its ability to isolate low-frequency vibrations.
As a rule of thumb:
– Higher static deflection = better isolation, but may allow more movement or sway.
– Lower static deflection = stiffer support, better for high-frequency or precise applications.
When selecting a mount:
– Estimate the deflection based on your equipment’s weight.
– Check that the deflection is within the optimal operating range of the mount.
– Avoid over-compressing (which can bottom out the mount) or under-loading (which reduces vibration damping).
5) Environmental Requirements
The environment that the anti-vibration mount needs to operate in can severely affect its lifespan. You need to consider the below criteria:
– Temperature Range
– Exposure to chemicals such as oil
– Outdoor vs indoor use
6) Mount Orientation
Mount orientation refers to the direction and type of forces the anti-vibration mount must handle typically axial (vertical), radial (horizontal), or multi-directional loads.
Stud mounts are generally only suited to compressive (vertical mounting) and are not suitable for side mounting. Any exposure to shear directional forces (horizontal movement) can risk tearing or breaking the stud mount overtime.
For side mounting, and effective shear and multi-directional vibration isolation, we always suggest using an anti-vibration bush or washer solution.
How Often Should Anti Vibration Mounts Be Checked?
To ensure a long operating life and maintain optimal vibration isolation, regular inspections are critical. We recommend the following inspection frequencies:
– Every 6–12 months for standard applications.
– Quarterly inspections in high-vibration or mission-critical environments.
We would recommend replacing the vibration mount if you notice any damage or tear in the bush or stud mount body.
Selecting the correct anti vibration mount is essential for reducing noise, controlling vibration, protecting equipment, and extending service life. By carefully considering load requirements, vibration frequency, static deflection, environmental conditions, and mounting orientation, you can ensure reliable performance and effective vibration isolation.