Rules for selecting vibration isolators

Machines and devices used in industry, manufacturing, and construction can generate significant mechanical vibrations that disrupt their proper operation, accelerate equipment wear, and emit excessive noise.

Vibration isolation is crucial for protecting equipment, maintaining operational performance, ensuring safety, and reducing noise. Excessive vibrations can lead to component damage, failures, and costly repairs. Investing in appropriate vibration isolation solutions is essential.

At Power Rubber we offer high-quality vibration isolators — an effective solution that prevents the transfer of vibrations to floors, walls, and other machines. They protect machines, prevent structural damage, help preserve structural integrity, and minimize unwanted noise.

What are vibrations?

A vibration is a type of mechanical motion in which an object oscillates around an equilibrium point. It is characterized by frequency, amplitude, and energy. It can be caused by natural phenomena (earthquakes, wind, ocean waves) as well as artificial sources resulting from the mechanical movements of machines or tools used by humans that generate vibrations.

Industrial machines produce long-lasting vibrations that affect equipment lifespan, generate unwanted noise, and also the structural integrity of nearby buildings. To reduce the intensity of vibrations, a low natural frequency of the system is required. To achieve this, rubber dampers must be used.

Impact of vibrations on equipment performance

Uncontrolled vibrations can disrupt machine operation and generate excessive noise. Shocks cause serious damage to mechanical systems, operational problems, shortened equipment life, and have a negative impact on operational performance, as well as the reliability, safety, and comfort of employees.

What are vibration isolators and what are they used for?

Effective vibration control is the basis for reliable and safe operation of machines in an industrial environment. Vibration isolators are designed to effectively isolate the vibrations generated during their operation. They are placed between the device and the base. A suitable vibration isolator minimizes or completely absorbs and damps the vibration energy transmitted to the base.

Why is vibration isolation so important?

Operating machines and devices are often exposed to high-frequency vibrations. Vibrations and shocks negatively affect human health, shorten equipment life, and cause damage to structures or entire buildings.

Selecting the appropriate vibration isolators brings a number of benefits, including:

• optimal control of vibrations and noise, including structural noise
• mitigation of the impact of excessive noise and vibrations on workers' health (a quieter and more comfortable working environment)
• improved working conditions and quality of work
• protection of equipment against excessive wear
• reduction in the number of failures, minimization of repair and maintenance costs
• energy efficiency and improved operational performance

Selection of vibration isolators for machines and equipment

Below are the most important principles to consider when selecting appropriate rubber dampers:

Determining the total mass of the device and the maximum load of the vibration isolator

The mass of the machine directly affects the type and size of the vibration isolator. Each vibration isolator has a specified range of maximum load at which it maintains optimal isolation effectiveness. We must know the total mass of the machine in order to evenly distribute the appropriate number of dampers at different points of the device. The number of vibration isolators depends on the mass and construction. The greater the total mass, the larger the mounts must be or the greater the number needed to reduce machine vibrations. It is worth remembering not to overload any of the elements, as this may lead to loss of isolation effectiveness and faster wear.

Vibration characteristics

The forcing vibration frequency and the resonant frequency are key parameters when selecting vibration isolators.

• forcing vibration frequency — the frequency at which the device generates vibrations (e.g., motor rotational speed)
• resonant frequency — should be significantly lower than the forcing frequency to avoid amplification of vibrations

The ratio of the frequency of the force causing the device vibrations to the natural frequency of the isolator directly affects the effectiveness of vibration isolation.

Dynamic loads and number of cycles

In machines where periodically variable forces occur (presses, compressors), in addition to static mass, dynamic forces must be taken into account. Rubber dampers should be matched to the machine's mass and the frequency of vibrations it produces during operation. The number of strokes per minute determines the frequency of vibrations that must be effectively damped. If the machine's vibration frequency approaches the natural frequency of the vibration isolator, resonance may occur, i.e., uncontrolled amplification of vibrations instead of their damping. Therefore, knowing the cycle frequency allows selecting the appropriate type of vibration isolator.

Static load

Static load is one of the key parameters that must be considered when choosing a vibration isolator. It must be matched to the weight of the device and the distribution of the load on the individual support points. Static deflection is the amount by which the damping mount compresses under the weight of the machine. The greater the static deflection, the greater the load it carries. Exceeding the static load leads to permanent deformations or even damage to the element.

When selecting, it is also worth considering the stiffness of the vibration isolator, which affects its deflection under load and the natural frequency of the system. Too high stiffness may limit the effectiveness of vibration isolation, while too low stiffness may lead to excessive deflection of the element. Therefore, the stiffness of the vibration isolator should be chosen appropriately to the mass of the device, the load, and the characteristics of the generated vibrations.

Operating conditions

The environment in which the machine operates has a huge impact on the choice of isolator. Selecting a single vibration isolator with regard to temperature fluctuations is crucial for damping effectiveness and durability. It is important to know the range of temperatures to which the system will be exposed. Working at too high a temperature can cause degradation of the rubber from which the damper is made and loss of damping properties. At low temperatures, elastomers harden, which limits their flexibility.

To properly select a vibration isolator, it is necessary to check whether the material from which it is made is suitable for the specific chemical environment of operation.

Rules for selecting vibration isolators - what else to pay attention to?

The proper selection of vibration isolators (vibration damping elements) aims to choose the right components to limit the transfer of vibrations to the building structure or device. As mentioned earlier, the task of vibration isolators is the effective isolation from vibrations that can affect the durability and lifespan of machine components and user safety. This is particularly important for rotating machines (e.g., fans), where vibrations occur at high frequency, expressed in Hz or revolutions per minute (RPM).

In the earlier part of the article we drew attention to a very important issue, namely: comparing the natural frequencies of the system with the forcing vibration frequency. Here we want to emphasize that effective vibration isolation requires the natural frequency of the system to be at least 1.4 times lower than the forced vibrations. This is crucial in ensuring an appropriate level of vibration isolation without affecting the operation of the rest of the system.

The method of mounting is also crucial here. Vibration isolators must be mounted symmetrically with respect to the center of gravity and tightened evenly. The mounting point, i.e., the distance from the axis of vibrations, is extremely important. For uneven floors, self-leveling vibration isolators are used (they have an adjustment screw with a nut) that adapt to the floor slope.

Many models of vibration isolators are available on the market (with blind threaded holes, on a metal plate with mounting holes, equipped with spring elements with built-in thread or bushing, etc.). Rubber dampers intended for contact with food should be made of materials approved for such conditions.

In summary, when selecting vibration isolators one should be guided primarily by the mass of the device, the characteristics of the vibrations, the required level of damping, and the operating conditions. One should also take into account the method of mounting, the type of fastening, and the type of holes in the base.

High-quality vibration isolators available at the Power Rubber store

At the Power Rubber store we offer a wide selection of vibration isolators tailored to different machines and working conditions. Our products effectively isolate vibrations, preventing damage to machines and devices sensitive to vibrations. This translates into lower maintenance costs and reduced downtime.

Why buy vibration isolators at Power Rubber?

Vibration isolators from Power Rubber provide stability and durability, even in tough conditions. They significantly improve operational performance, reduce energy consumption, and reduce noise and nuisance in industrial and residential environments.

Thanks to experience and industry knowledge, we offer professional support in selecting the appropriate vibration isolators. By using the knowledge of our experts, you gain confidence that the purchased rubber damper will create a more pleasant working environment and increase worker safety, while allowing machines to operate more efficiently.

Choose the appropriate vibration isolator for a specific machine (milling machines, presses, planers, air conditioners) without shifts, play, or secondary vibrations.

For all inquiries please contact the phone number: +48 22 292 40 24 or +48 505 16 03 03, or by e-mail (power|powerrubber.com| style="color: rgb(0, 91, 171); border-bottom: 1px dotted rgb(0, 91, 171);"|Power|PowerRubber.com) or via our contact form