Designing with VIB320 Vibration Isolation Bearings


Newport's VIB320 Series isolators utilize patented VIBe™ technology to attenuate the transmission of vibrations without the need for electronics, air hoses, compressor or other supporting hardware. They offer robustness for tough environments, quicker settling time than pneumatic isolators and maintenance-free operation. As the isolators are mechanical and passive, they are easy to mount and design into sensitive applications such as microscopy and precision measurement, inspection and manufacturing. These isolators are also a featured component of Newport's VIP320 Series general purpose vibration isolation platforms and VIP3200 Series microscope vibration isolation platforms.

VIBe™ Isolation Bearings

The VIBe isolation bearings filter the transmission of micro-vibrations in six degrees of freedom, cutting off the transmission of vibrations at low frequencies. They are scalable and easily adapted to a wide range of applications. VIBe technology is based on a proprietary combination of two non-linear spring filters: a horizontal and vertical spring filter.


Horizontal Spring Filter

In the horizontal direction, VIBe technology utilizes steel ball bearings sandwiched between precision raceways to form a plane of isolation. When under load, the bearings will deflect horizontally if a horizontal force is applied above or below the plane of isolation. Micro-vibrations cause the balls to displace between the two raceways and cut off the transmission of vibrations. The balls that displace are restored to the neutral position by gravity, which acts as a non-linear spring. Since the spring force (i.e., the restoring force) is non-linear, it is constant and independent of the frequency and amplitude of the input vibrations, meaning the balls' oscillating motion has no "natural" frequency. Instead, the oscillating motion has an infinite number of frequencies, one for each increment of displacement, making the resonance between the two halves of the plane of isolation physically impossible. As a result, the horizontal spring filter filters out (whites out) a broad band of input vibration frequencies and ensures a constant level of vibration transmission reduction.


Vertical Spring Filter

When a payload is placed on the isolation bearings, they will deflect. Vertical vibration isolation is achieved by effectively levitating the payload with a quasi-rigid body: Newport's proprietary non-linear spring mechanism with near-zero tangential stiffness for micro-vibrations. The natural frequency of the spring remains relatively low and constant across a large range of spring compression for which the compression force is matched by the restoring force. In this range, a low percentage of vibrations is transferred through the spring filter.


Load Capacity

The VIB320 Series isolators will isolate a range of payloads as low as 2 lbs. (0.9 kg) to as heavy as 180 lbs. (81.8 kg), depending on the part number selected. VIB320 isolators must be loaded with sufficient weight to compress the bearings without overloading them. Thus, it is critical to choose the proper parts to match your application.

The VIB320 Series family page lists each isolator's part number and corresponding minimum and maximum load capacities. Select a part whose minimum and maximum load capacities bracket the weight that each bearing will carry. If the payload falls within the minimum and maximum range of more than one part number, select the part for which the payload falls closest to the middle of the range.

In cases where the load distribution on a platform is not uniform (for example, microscopes are typically heaver in the rear by as much as 50%), VIB320 isolators with different load capacity ratings may be used in a system. For a typical tool configuration with 4 VIB320 isolators, the maximum payload that can be isolated is 720 lbs. (327 kg), i.e., 4 * 180 lbs. (4 * 81.8 kg). If you need to isolate a heavier payload, please contact us.

Confirmation of Proper Loading

A special "gap tool" is shipped with the isolators to verify proper loading. This gap tool measures 0.56 in. wide by 0.1 in. thick. When the bearing is under compression, the gap in the bottom half of the isolator (see below) should be greater than 0.1 in. but less than 0.56 in. to ensure that the payload is isolated. Thus, if the 0.56-in. portion of the tool fits in the gap, then the bearing does not have sufficient weight on it. Additionally, if the 0.1-in. portion of the tool does not fit in the gap, then the bearing is overloaded.

Incorrect: The 0.56-in. portion of the tool fits in the gap, meaning the bearing does not have sufficient weight on it.
Correct: The 0.56-in. portion of the tool does not fit in the gap.
Incorrect: The 0.1-in. portion of the tool does not fit in the gap, meaning the bearing is overloaded.
Correct: The 0.1-in. portion of the tool fits in the gap.

Shear Capacity

VIB320 Series isolators are designed to support the vertical load of an isolated payload and to attenuate the transmission of vibrations. However, they are not designed with significant capacity to withstand the potential large shear force that can occur in transit, loading and unloading, or during an earthquake. Therefore, a method of locking the bearing should be designed into the system for protection during transit, loading and unloading. Furthermore, a snubber or other method of preventing shear displacement of the isolated payload during a seismic event should also be designed into the system.

Attachment to a System

VIB320 Series isolators can be bolted down to a tool frame or other support surface, and they can be mechanically attached to the underside of a steel or aluminum plate, honeycomb panel, granite block or other surface.

Mounting to a Tool Frame

VIB320 Series isolators can be mounted to the top of a tool frame or other supporting structure with one of Newport's square, round or rectangular adapter plates designed specifically for the VIB320. There is no functional difference among the adapter plate shapes, and each adapter is 0.25 in. (6 mm) thick. For more information about these adapter plates, which must be ordered separately from the isolators, please see VIB320 Accessories.


Mounting an Isolated Plate

To mount an isolated plate to the top of an isolator, Newport provides a variety of threaded leveler studs and threaded leveler bars that can be mounted to the top of the VIB320 Series isolators. In this manner, the isolator can then be attached to another plate or platform. Each option also provides ±0.20 in. (5 mm) of vertical adjustment. For more information about these leveler studs and bars, which must be ordered separately from the isolators, please see VIB320 Accessories.


Height of the Isolators

The height of the isolators without any adapter base plates or leveler attachments is 2.35 in. (59 mm) before a payload is placed on them. Once under load and within the proper operating load capacity range, the height of the isolator will range between 1.85 in. (47 mm) and 2.25 in. (57 mm), before adding the additional height for the adapter plates and leveler attachments. Each base adapter plate adds 0.25 in. (6 mm) to the height.

Two factors affect the height of the isolator when in use. First, the bearing deflects ±0.20 in. (5 mm) from its mid-deflection point. Next, both the leveler stud and leveler bar attachments can be adjusted ±0.25 in. (6.35 mm) from the mid-point setting. Thus, while there is no guarantee that each bearing will deflect to the same degree, since each leveler attachment is vertically adjustable, the isolated plate above the bearings can be raised or lowered to ensure it is level.

VIBe Isolation Platforms

Newport offers a comprehensive set of table top isolation platforms that provide vibration isolation for microscopes and other benchtop applications. VIBe technology is a featured component of the VIP320 Series general purpose vibration isolation platforms and the VIP3200 Series microscope vibration isolation platforms.

VIP320 General Purpose Platforms

VIP320 Series platforms consist of a stiff steel plate supported by 3 or 4 VIB320 Series isolators. They are well suited for applications such as shakers, microscopes and inspection tools. Platform sizes range from 12 in. x 18 in. (305 mm x 457 mm) to 26 in. x 38 in. (660 mm x 965 mm), and loads of up to 520 lbs. (235.9 kg) can be isolated. If one of our standard combinations of platform and VIB320 isolators does not quite fit your requirements, you may configure your own VIP320 platform by purchasing the isolators, baseplate and isolator mounting brackets and other accessories separately.


VIP3200 Microscope Platforms

Building vibrations and disturbances from surrounding lab equipment can impact a microscope's performance. Thus, an effective vibration isolation and control system must offer high-performance vibration resistance while maintaining a compact, low profile to decrease space requirements and increase usability. Newport's VIP3200 Series platforms with VIBe technology are the ideal solution for mounting and isolating microscopes. These platforms have been specifically designed for Olympus, Nikon, Leica and Zeiss microscopes and are especially useful with upright and inverted light microscopes.