WHEN TO REPLACE THE ANTI-VIBRATION MOUNTS OF A MACHINE OR SUSPENDED ELEMENT?

In all suspended assemblies where anti-vibration mounts are present, with use and years of service the characteristics of the mounts can be affected and even damaged. This in turn has a negative effect on the vibration isolation performance and the correct operation of the system.

It is therefore important to know how to detect when the anti-vibration mounts of a machine or a suspended element require replacement. In the following article we show some recommendations and give advice about the need to replace an anti-vibration mount.

REPLACING ANTI-VIBRATION MOUNTS: SIGNS OF A WORN OR DAMAGED MOUNT

During the operation of a machine or suspended element, there are different signs that can appear when a support is worn or damaged. Below we list some of the symptoms that anti-vibration mounts can present and that will allow us to recognize if they need a replacement:

1. Increase of the vibration levels in the system

If the vibration levels of the system are higher than usual, this may be a sign that the anti-vibration mounts are worn and may need to be replaced.

2. Excessive movement of the suspended element

If a support is worn or damaged its mechanical properties may be affected, this therefore may also affect the dynamic behavior of the system, for example reducing the overall stability of the assembly. If a greater than usual movement is observed in the suspended assembly this would indicate that the anti-vibration mounts are damaged or worn.

3. Impact noises

A worn mount can often lead to knocks or bumps within its environment. This is due to the suspended assembly moving more than normal and making contact with other components. This can cause impact sounds that become quite noticeable.

4. Reduction of its initial height

With use and time, the internal polymeric chains of the rubber can become damaged due to repeat loading cycles, this results in fewer supporting chains which must carry the same load. Therefore, if it is observed that the installed height of the mount is lower than when it was initially installed, this is a sign that the piece may be worn. A good visual indication of this can be if the distance between the metallic elements is close and about to make unwanted contact.

5. Visual appearance of the support

If there are signs of significant corrosion, cracks or high permanent deformations, wear will be occurring on the rest of the support. Below we have made a visual overview of the different areas we need to focus on to assess whether or not the mounts should be replaced.

1. Loss of adhesion between bonding of metal to rubber

2. Presence of oil, diesel,… on the mounts

3. Excessive corrosion on metal parts

4. Visible cracks in the rubber section

5. Visible damages

6. Very low height on the mounts

6. Other factors to take into account

There are other factors that can also compromise the life of the mount, and therefore cause damage or premature wear on the mounts. Some of the most common are:

1. Incorrect installation of mounts.
2. Aging / hours of use.
3. Shocks or excessive dynamic loads that can damage the supports of the suspended assembly.
4. Incidents/accidents that have caused damage or moved the anti-vibration mounts of the suspended assembly.
5. Liquid leaks (oil, diesel,...) on the supports, contaminating the elastomer.

If you experience any of these signs or suspect that any of the above reasons may be relevant to your application, we recommend to check your mounts and consider replacing them.

AMC MECANOCAUCHO® manufactures anti vibration mounts and has a team of application engineers willing to help with your installation needs, do not hesitate to contact our technical department if you require help on this topic.