Model VPBIdeal for mounting heavy components
Standard and vibration damped versions
Available with gear rack to assist in vertical positioning
Heavy duty optical support rods are 1.5 inch (38.1 mm) diameter and are made with steel for greater rigidity. We offer both damped and undamped optical support rods.
All Newport optical support rods are made entirely of steel. Steel provides much greater dynamic rigidity than aluminum due to its almost order-of-magnitude greater material loss factor. This means even our undamped rods have the high resonant frequency and correspondingly low vibration amplitude required for optical laboratory use. Also, with their inherently greater stiffness and strength, steel rods support larger loads with greater stability. Steel construction has other advantages; steel has half the thermal expansion coefficient of aluminum and a higher heat capacity so thermal stability is enhanced.
Optical support rod Models 40 and 70 have the sturdiness suitable for the majority of general laboratory applications. Both models are 14 in. (356 mm) tall. Model 70 has a nylon gear rack set into the rod for rack-and-pinion control over component elevation. Models 41 and 71 short rods are 7 in. (178 mm) tall and have a smaller resonant vibration amplitude than the longer rods. Their low profile makes them ideal for compact experimental setups. Models 42 and 72rods, which have integrated bases, are a full 24 in. (610 mm) tall for use in experimental setups requiring extra height such as laser beam routing for microscopy applications.
The optical support rods are made round to 0.0005 in. (12 µm) to mate repeatedly with the bore of every Newport rod-mounted component. A chromed finish is applied for a low-reflectivity surface that, unlike aluminum, is resistant to gouging, scratching and corrosion, allowing for many years of service.
All optical support rods attach easily to tables either with an integral tie-down bolt or a steel ring base. We offer a wide selection of precision components including clamps, platforms and optics holders that mount interchangeably on the rods for complete component mounting flexibility.
Model VPB
Model VPB Adjustable Base is a stiff, low-profile adjustable platform designed for stable mounting of Newport rods and components anywhere on our optical tables and breadboards.
Model VPB has XY sliding adjustments for complete positioning freedom on any mounting surface with a standard pattern of 1/4-20 (or M6) mounting holes on 1.0 in. (25.4 mm) centers.
Model 72 with two 370-RC Clamps
Models 45 and 75 Damped Optical Support Rods are the most sophisticated rods available for critical applications where acoustical and vibrational forces are a concern. These rods incorporate cylindrical masses constrained by damping layers, concentrated in the upper portion of the rod where they are most effective in dissipating vibrational energy. This construction is the result of extensive computer modeling, dynamic testing and structural analysis. Newport’s patented internal damping system provides unmatched vibrational immunity. Compared to the best alternative designs, Newport damped optical support rods exhibit 60% higher resonant frequency, 100% faster vibration decay and 160% better peak compliance. These 14 in. (356 mm) long rods mount to tables and breadboards with four bolts through a special ring base. Model 75 has a nylon gear rack for rack-and-pinion control over component elevation.
The time-domain responses shown in Figures 1 and 2 dramatically illustrate the difference between the Newport approach and alternative damping implementations when the rod is supporting a load.
Fig. 1: Time response of a Newport Model 45 Damped Rod supporting a 2.5 lb (1.1 kg) load.
Fig. 2: Time response of an alternative, lead-shot damped rod with the same 2.5 lb (1.1 kg) load as Fig. 1.
Newport’s Model 40 undamped steel rod has a single resonance peak at 240 Hz corresponding to the first bending mode of a cantilevered beam.
The alternative, lead-shot damped rod has a single resonance peak roughly 1/4 the amplitude of the undamped rod. This peak is lower in frequency (~105 Hz) because of the lower stiffness-to-mass ratio of this construction, which makes it more likely to couple to vibrations from nearby mechanical and electrical components.
Newport’s Model 45 damped rod is so highly damped that the 240 Hz resonance is split into subpeaks at 170 and 210 Hz whose amplitudes are 40 times less than the undamped response peak and 5 times less than the alternative rod.