TMC CleanBench 63-500 Series Vibration Isolation Laboratory Table

CleanBench is the next generation of our industry-standard 63 series lab tables. TMC's vibration isolation lab tables lead the industry in performance and are ideal for various applications, including AFM, Confocal Microscopy, IVF, Patch-Clamping, Interferometry, and Metrology. CleanBench incorporates TMC's unique Gimbal Piston Vibration Isolators and a tabletop with enhanced performance and features. 

Unique new table-top design (patent pending) combines the best features of TMC's CleanTop steel honeycomb tops with our ultra-stiff, damped, layered platform design.

Greater stability, especially for small-size tables. The low-profile, high-density tops lower the overall floating center-of-mass, ensuring inherently stable, even for relatively top-heavy payloads.

Guided thread lead-ins to align screws with tapped holes. The "bevel" shape eases the engagement of the first thread.

Ergonomics are optimized for the seated user by minimizing the thickness of the tabletop.

Other designs offer 100 mm, 4 in. thick tops that awkwardly separate knees and elbows or sacrifice essential mass by providing a 50 mm, 2 in. thick honeycomb top, which does not have an adequate mass for effective vibration isolation, especially for smaller table sizes.

All CleanBench tables incorporate TMC’s Gimbal Piston Air Isolators as a standard feature. The Gimbal Piston has consistently outperformed other air isolators in side-by-side testing. It offers outstanding low-frequency vibration isolation in all axes and maintains its performance specifications even when subjected to deficient input levels of excitation. Proprietary damping techniques allow the Gimbal Piston to stabilize relatively top-heavy payloads and quickly dissipate disturbances of the isolated table top.

Benefits:

• Vertical and horizontal vibration isolation starting at 2 Hz


• Reduces vibration by more than 95% at 10Hz


• Virtually free of friction, avoiding rolling friction to static friction transitions


• Accommodates horizontal displacement by acting as a gimbal

The Gimbal Piston® Air Isolator provides outstanding isolation in all directions for even the lowest input levels. It is lightly damped and highly responsive to typical, low-amplitude ambient floor vibrations. It achieves very high damping for gross transient disturbances, such as sudden load changes or bumping of the top plate. The result is that Gimbal Piston Isolators provide superior isolation yet will virtually eliminate any gross disturbance within a few seconds. It can also stabilize isolated systems with relatively high centers of gravity without compromising isolation.

The greatest challenge in designing an effective isolator is maintaining good performance at the low vibration amplitude inputs typical of ambient building floor vibration. Isolator specifications are often based on measurements done with the isolator placed on a “shaker table” with very high amplitude input levels. Such testing, with input amplitudes on the order of millimeters, yields unrealistic performance expectations and is misleading as results will not reflect the actual performance.

The Gimbal Piston Isolator design uniquely maintains its stated resonant frequency and high attenuation level in even quiet, natural floor environments. The performance is linear to such low amplitudes because the design is virtually free of friction and, therefore, can avoid rolling friction to static friction transitions.

Every other system we have tested at levels typical for floor vibration exhibits a higher resonant frequency than claimed or a substantial increase in transmission through the isolator mount.

We stress the importance of performance specifications at low levels because we have repeatedly observed, in our testing and many as-used installations, that better performance is much easier to achieve at greater amplitudes and higher frequencies.

Horizontal vs. Vertical Inputs:

Our innovative Isolator allows a thin-wall, rolling diaphragm seal to accommodate horizontal displacement by acting as a gimbal. Instead of using a cable-type pendulum suspension, the Gimbal Piston Isolator carries the load on a separate top plate with a rigid rod extending into a well in the main piston. The bottom of the rod has a ball-end that bears on a hard, flat seat. An inherently flexible coupling allows horizontal flexure in the isolator as the ball simply rocks (without sliding or rolling) very slightly on the seat. The approach works exceptionally well, even with sub-microinch levels of input displacement, because the static friction is virtually the same as the rolling friction. Horizontal motion is converted to the usual vertical diaphragm flexure but out of phase: one side of the piston up, the other down, in a gimbal-like motion.

Limitations of Other Types of Vibration Isolators:

Thick- Wall Rubber Diaphragms. Most commercial isolators employ an inexpensive, thick-walled rubber diaphragm in the piston to achieve vertical isolation. Because of the relative inflexibility of these elements, low amplitude vibration isolation performance is compromised. Though such a system feels “soft” to gross hand pressure, typical low-level floor vibration causes the rubber to act more like a rigid coupling than a flexible isolator.

Sealed Pneumatic Isolators (Passive). Sealed air isolators do not automatically adjust to load changes. The primary limitation of such systems is that they must be made too stiff to be effective isolators. For example, a passive isolator with a proper 1.5 Hz resonant frequency would drift several inches vertically in response to small changes in load, temperature, or pressure and require constant manual adjustment. Thus, no practical sealed isolators are designed with such low resonant frequencies.

Bearing Slip Plates. In theory, bearing slip plates should allow horizontal isolation by their decoupling effect. For such a design to work at low amplitudes, it would require precision ground-hardened bearings with impossibly small tolerances. To get the bearings rolling, the commercially available versions cannot overcome the static frictional forces at low amplitudes. In addition, all such systems are challenging to align initially and easily drift out of calibration.

Homemade Assemblies. Homemade isolation systems - often a steel or granite slab placed on rubber pads, tennis balls, or air bladders - will work only if the disturbing vibrations are high frequency and minimal isolation is required. While all isolators use the principle of placing a mass on a damped spring, their performance is differentiated primarily by spring stiffness: the stiffer the spring, the higher the resonant frequency. Thus, homemade solutions are limited by their high resonant frequency.

A Gimbal Piston™ Isolator with a 1.5 Hz vertical resonant frequency begins to isolate at 2 Hz and can reduce vibration by over 95% at 10 Hz. A tennis ball under a steel plate with a 7 Hz resonant frequency begins to isolate above 10 Hz and reduces vibrations by 90% at 30 Hz. But most building floors exhibit their highest vibrational displacements between 5 and 30 Hz, so a tennis ball or rubber pad makes the problem worse by amplifying ambient frequencies between 5 and 10 Hz.

Features & Benefits:

Greater stability, especially for small-size tables. The low-profile, high-density tops lower the overall floating center-of-mass, ensuring inherently stable, even for relatively top-heavy payloads.

Ergonomics is optimized for the seated user by minimizing the thickness of the tabletop. Other designs either offer 4" (100 mm) thick tops that awkwardly separate knees and elbows or sacrifice essential mass by providing a 2" (50mm) thick honeycomb top, which does not have an adequate mass for effective vibration isolation, especially for smaller table sizes.

Our Patented Gimbal Piston™ Isolator has been proven by independent tests to outperform the competition consistently. It achieves both horizontal and vertical isolation down to deficient input levels.

Thin-Wall Rolling Diaphragms — An integral part of the Gimbal Piston, the thin-wall, dacron-reinforced, rolling diaphragm air seals are only 0.020 in. (0.5 mm) thick and highly flexible. They do not stiffen the spring as thicker rubber diaphragms do.

Aluminum Height Control Valves — All systems have rugged aluminum height control valves. Virtually unbreakable, they are finger-adjustable with no need for tools. The standard model maintains height to ± 0.050 in. (± 1 mm); the precision model to ± 0.005 in. (± 0.1 mm).

Internal Piston Travel Restraint — Unique in the industry, TMC provides husky, tamper-proof, built-in piston travel restraints. The restraints are independent of the table valves and have been ram-tested at forces above those produced by the pistons operating at full pressure. They cannot be decoupled accidentally and do not interfere with setting up and using the table. Still, they protect against overtravel without using external bars that create hazardous pinch points. Heavy loads, including the top plate, can be safely removed from a table in full operation.

Rugged Built-in Leveling Feet — Table legs include built-in fine-thread 3 in. (75 mm) diameter screw jack levelers with 1/2 in. (13 mm) travel, provision for external adjustment, and a handy adjustment wrench. The base is a solid, slightly domed shape to ensure reliable, wobble-free contact with sloping or irregular floors.

CleanBench with Rigid Non-Isolating Legs:

CleanBench is offered in an economical leveling mount option with rugged, adjustable jack screws that provide +2 1/2 and -0 in. (+62 and -0 mm) of travel. Later, you can upgrade the system to full vibration isolation performance, with a total cost of only slightly more than if you initially opted for this feature.

Guided thread lead-ins to align screws with tapped holes. The "bevel" shape eases the engagement of the first thread.

Ergonomics is optimized for the seated user by minimizing the thickness of the tabletop. Other designs either offer 4" (100 mm) thick tops that awkwardly separate knees and elbows or sacrifice essential mass by providing a 2" (50mm) thick honeycomb top.

Tiebar Gussets — Exclusive TMC tiebar gussets increase table frame rigidity. They compensate for eliminating the front tiebar to provide knee wall space. Rugged Built-in Leveling Feet Table legs include built-in fine-thread 3 in. (75 mm) diameter screw jack levelers with 1/2 in. (13 mm) travel, provision for external adjustment, and a handy adjustment wrench. The base is a solid, slightly domed shape to ensure reliable, wobble-free contact with sloping or irregular floors.

Superior Table Tops — Our standard laminated tops provide an attractive stainless steel ferromagnetic working surface with highly damped, high stiffness construction at low cost. For applications requiring the ultimate stiffness and damping or mounting holes, specify our patented CleanTop® II honeycomb top.

Table Top Dampening & Compliance:

Structural Damping determines how quickly an excited resonance in a tabletop decays. The simplest way to measure damping is to hit the tabletop with a hammer and measure the decay with an accelerometer, oscilloscope, or spectrum analyzer. The height of a resonance peak in the "compliance curve" also measures damping.

Compliance is a reciprocal measurement of the dynamic stiffness of a tabletop. The data are obtained by inputting a measured force to the tabletop with a calibrated hammer and measuring the resultant acceleration (or displacement) with an accelerometer. Compliance is the ratio of displacement to force expressed as a function of frequency.

Isolator Performance

All CleanBench tables incorporate TMC's Gimbal Piston Air Isolators as a standard feature. The Gimbal Piston has consistently outperformed other air isolators in side-by-side testing. It offers outstanding low-frequency vibration isolation in all axes and maintains its performance specifications even when subjected to deficient input levels of excitation. Proprietary damping techniques allow the Gimbal Piston to stabilize relatively top-heavy payloads and quickly dissipate disturbances of the isolated table top.