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Vibration Isolation Table Setup

Microsanj systems are commonly installed on a pneumatic vibration isolation table to minimize measurement noise from building and floor vibration. The setup instructions below are from the table manufacturer's (Technical Manufacturing Corporation, TMC) CleanBench™ (63-500) Series High-Performance Lab Table guide. TMC's CleanBench (63-600) ClassOne™ and (68-500) High-Capacity tables use the same basic setup procedure, with the exceptions noted at the end of this section.

Introduction

CleanBench (63-500) Series laboratory tables use Gimbal Piston Isolators that require a continuous supply of compressed air or nitrogen to operate properly.

Tools required: - Leveling wrench (provided) - 5/16 inch Allen wrench for accessories (provided) - Utility knife - 3/4 inch wrench (for casters)

Air Supply Plumbing and Valve Setup

Air supply input connection

  1. Plumb tubing between your air supply and the system's input air filter as appropriate. Tubing connects to a 1/4 or 1/8 inch NPT female fitting via an adapter (1/4" NPT male to straight connector / 1/8" NPT female / 1/8" NPT male thread, 1/4" OD tubing).
  2. To connect, insert the air tube firmly into the self-sealing fitting.
  3. To disconnect, push the orange cylinder with your thumb and forefinger toward the center of the fitting body while pulling the tube in the opposite direction.

[diagram/image in source — not reproduced here: air supply input connection fitting diagram]

Internal air supply tubing

Systems are internally plumbed at the factory. In the standard 4-isolator configuration, one isolator is the "Master" (M) with a height control valve (V), and the other isolators are "Slave" (S) isolators with no valve.

[diagram/image in source — not reproduced here: valve schematic for a 4-isolator system]

Note: Each post ships with a short section of tubing with a union coupler already attached to the input elbow (a "pigtail"). Do not tamper with this segment — each pigtail contains a small, flow-restricting orifice that damps table motion and stabilizes the load.

Important: Do not remove or change the location of these orifices. If one is lost or damaged, contact TMC for a replacement pigtail.

Installing and Leveling the Tabletop

  1. Ensure the main air supply is off.
  2. Using the leveling wrench provided, adjust the leveling feet so all four legs are in solid contact with the floor. Level the frame by referencing the top surface of the horizontal tie-bars — carpenter-accuracy leveling is adequate. (Skipping this step may compromise vibration isolation performance.)
  3. Place the tabletop slowly and symmetrically down onto the deflated isolators to avoid damaging them. The top should be centered symmetrically over the isolator frame. If the floor is uneven and one of the four isolators does not contact the payload, close that gap by further lowering the leveling foot on the corresponding post.

CAUTION: Tabletops weigh approximately 275–300 pounds. Take proper precautions when handling.

[diagram/image in source — not reproduced here: tabletop placement over the four isolator legs]

Attaching Horizontal Lever Arms

  1. Locate the three height control valves mounted on the isolators.
  2. Ensure the main air supply is off.
  3. Adjust the ISOLATOR HEIGHT ADJUST screw clockwise (viewed top-down) to lower the foam pad to its lowest position, close to the horizontal lever arm. Retract the locking nut as needed.
  4. Using a marking pen, mark a spot on the edge of the foam pad's silver-colored base to use later as a rotation indicator for the ISOLATOR HEIGHT ADJUST screw.
  5. Insert the horizontal lever arm onto the height control valve, ensuring the end of the horizontal lever arm screw fits over the center of the brass spacer on top of the valve.
  6. Loosely fasten the horizontal lever arm with the horizontal lever arm screw (red knob) and adjust so the arm sits approximately horizontal, or the foam pad makes slight contact with the tabletop — whichever occurs first.
  7. Repeat this process to attach the horizontal lever arm to each of the remaining two valves.

[diagram/image in source — not reproduced here: height control valve and horizontal lever arm assembly]

Isolator Height Adjustment

  1. Adjust the ISOLATOR HEIGHT ADJUST screw to raise the foam pad until it is in slight contact with the tabletop (unless already achieved in the previous step).
  2. While observing the mark made earlier on the foam pad's base, continue adjusting the ISOLATOR HEIGHT ADJUST screw another 5–10 turns counterclockwise (or more, depending on the system model). The foam pad material will compress against the tabletop.
  3. Repeat this height adjustment on the remaining two isolators that have a valve attached.

Gimbal Piston Adjustment

  1. Turn on the main air supply and set it to 60–80 psi max. After a short delay, all load disks should lift away from the clamp rings and the tabletop will float.
  2. On systems with Gimbal Pistons, check that the top of the piston and the top surface of the clamp ring are parallel. If the Gimbal Piston is tilted, slide or tap the load disk toward the low spot of the piston to correct it.

Note: Centering the Gimbal Piston mechanism is important for the best horizontal isolation performance. The mid-point of the vertical range is set by the gap between the bottom surface of the load disk and the top surface of the clamp ring: - 4×4 inch cross-section isolators: 3/8 inch gap - 6×6 or 8×8 inch cross-section isolators: 1/2 inch gap

Some deviation from these gap heights may be necessary for proper leveling. The tabletop should be free to move both vertically and horizontally; any further leveling should be done only with the ISOLATOR HEIGHT ADJUST screw.

[diagram/image in source — not reproduced here: Gimbal Piston gap diagram]

  1. Tighten the locking nut on the ISOLATOR HEIGHT ADJUST screw for all three valves.

Note: Expect some slight settling and improvement in valve height sensitivity over the first few days of operation. Re-adjust the ISOLATOR HEIGHT ADJUST screw if required.

Adjust Air Pressure

  1. Adjust the regulated air pressure down to 15–20 psi above the single gauge pressure reading. This optimizes damping control of coarse disturbances.

Note: Reducing the supply pressure differential minimizes the prolonged disturbance effects of sudden payload forces. The valves must maintain a positive supply differential, or air will be exhausted and the system will deflate. Air flow through the valves is buffered with controls built into the isolators.

Troubleshooting Tips

Table not floating properly — If a slave piston is too high or too low, adjust the HEIGHT ADJUSTMENT screw on the master valve controlling it to raise the piston. For the piston diagonally opposite, slightly adjust its HEIGHT ADJUSTMENT screw in the opposite direction.

Instability — If the table oscillates uncontrollably, turn off the air supply and contact TMC. This is typically caused by a combination of high mass and high center of gravity and can be corrected.

Poor isolation — Ensure the tabletop is free to move vertically and horizontally; recheck the "Installing and Leveling the Tabletop" steps above.

Pistons completely down — If isolators do not rise from the down position, the leveling valves are not adjusted correctly, or air supply pressure is insufficient.

Pistons completely up — If an isolator cannot be lowered from the up position, the leveling valves are not adjusted correctly, or the system is not plumbed correctly. Recheck the air supply plumbing described above.

Accessories

The CleanBench platform supports several optional accessories. Full assembly instructions (fastener sizes, hole patterns, and part numbers) are provided with each accessory kit in the original TMC guide; summaries below are for reference only.

  • Faraday Cages — Available as a Type II cage (mounts to a full perimeter enclosure on 63-500 series tables) or a Bench Top model (mounts on a base plate for bench-top use). Includes a front panel with a retractable window shade, side/rear/top panels, and an optional hanging shelf. Assembly uses provided hardware (10-32 and 6×1 inch screws, hold-down clips) and a Phillips screwdriver plus 3/8 inch wrench.
  • SpaceSaver™ Overhead Rack — An overhead frame system (upright angles, horizontal side/rear rails, top shelf) that mounts to the isolator legs via Post Wrap Clamps. Supports optional front/rear support bars, a keyboard shelf, a monitor arm, and a power strip. The table should be fully set up and leveled, and the isolators de-pressurized with air supply off, before installing this rack. Installation is recommended with two people.
  • Support Bars — Attach support bar brackets to the support bar, then attach the brackets to the top inside face of the isolator posts and tighten all bolts.
  • Sliding Shelves — Mount via a shelf clip that rests in a groove in the front support bar; the rear of the shelf rests on the rear support bar.
  • Perimeter Enclosure — Attach perimeter enclosure brackets to the top inside face of the isolator posts and tighten all bolts, then lower the enclosure over the tabletop onto the attached brackets (bracket "tongues" fit into "slots" on the underside of the enclosure).
  • Casters — Shipped attached to the base of the isolator legs. Rotate the caster HEIGHT ADJUST screw with a 3/4 inch wrench to engage or disengage. Retract casters when not in use for optimum isolation performance.

Other CleanBench Table Series

  • CleanBench (63-600) Series ClassOne™ Workstations — Setup is the same as the 63-500 series, except: caster design differs; height control valves are physically slightly different but adjust the same way; the standard front support bar differs from the 63-500 series; and an optional rear support bar and sliding shelf are available.
  • CleanBench (68-500) Series High-Capacity Lab Tables — Setup is the same as the 63-500 series, except: the tabletop is much heavier; the legs have a larger cross-section and higher support capacity; and casters are the same type used on System 1 posts (6×6 inch posts).