Answer»
- Vibro/Dynamics rates isolation effectiveness as a percentage COMPARED to the levels that would exist if the machine were anchored or “hard mounted”. It is not possible to obtain 100% with a passive isolation system, but you can come close.
- When selecting isolators, many factors are taken into account. But it usually comes down to two issues: How much isolation is required and how much motion can be tolerated? Isolators are usually selected to achieve the highest amount of VIBRATION isolation possible while keeping motion to an acceptable level. These are conflicting goals. To reduce machine motion, the stiffness of the isolator is often increased, at the detriment of isolation, resulting in some vibration being felt in the floor.
- Inertia Force, which is the force generated by the motion of the press slide, is another possible cause of remaining vibration in the floor. Run the press WITHOUT material to see if inertia is the cause of the vibration. If vibration is felt, then inertia is CONTRIBUTING to the vibration in the floor.
- Elastomeric isolators are not usually designed to ISOLATE inertia force. These are high-tuned isolators, which mean the isolator’s natural frequency is higher than the operating speed (SPM) of the press, resulting in no inertia force isolation. In order to isolate inertia force, the natural frequency of the isolator must be lower than the operating speed of the press. Vibro/Dynamics VS Series Spring Isolators have natural frequencies as low as 2.5 Hz., which is ideal for machines running over 250 SPM. Added weight is usually required to keep press motion to an acceptable level.
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