Adjusting for Mechanical Drift

Over time, you may experience mechanical drift in one or more of the axes of your manual micromanipulator. Here we show you how to adjust for that. The process is similar for other styles of manual micromanipulators. We will look at the process for adjusting all three axes of a KITE micromanipulator.

 

 

A micromanipulator axis may begin to move gradually under its own weight even if it's not being touched. This phenomenon is referred to as mechanical drift, and it occurs from normal use of the manipulator axes over time. Each coarse axis control of the micromanipulator has its own separate adjustment to counteract drift. Let's look at the popular M3301 Micromanipulator. The procedure we're using also works for an MD4, a KITE and an MMJ Micromanipulator. Each course axis control on the micromanipulator has its own adjustments. Your X, Y and Z axis controls are located on a single plane at the back of the manipulator. The X-axis fine control is on the top, the X-axis course control is in the center and the Y-axis control is on the bottom. The Z-axis course control is locate behind the Y-axis knob, and in between the two is an adjustment ring. On the adjustment ring is a tiny screw that we will adjust. y

X-Axis Adjustment

Let's start with the X-axis control. We're going to use the Allen key provided, and it fits into the hex screw hole on the side of the X-axis control knob.

 

  1. Before we start, drive the axis all the way to the end of its travel to give us as much room as possible.

  2. Place the Allen key in the screw hole on the X control knob and loosen it. DO NOT take the screw out, because it is challenging to reinstall it.

  3. Adjust that outer ring of the knob. To prevent the axis from moving while we're making the tension adjustment, hold the slide securely and then rotate the adjustment knob until you feel it catch. The resistance of the knob begins to increase as it compresses against the spring steel and the nylon friction components inside.

  4. Adjustment is a little bit arbitrary, so when the amount of tension feels just about right, then you go ahead and tighten it up again. 

  5. Once you got it where you want, you can test it. Push on the end of the slide with your hand and see how easily it moves. When the tension is adjusted correctly, it will not be easy to move the axis. If it's not quite right, you may need to go back and try it again until you get it just exactly where you want it. It takes a little bit of patience. It may take two or three tries.
  6. If the x action feels too tight or too loose then you unscrew it, and you do it again. Typically the goal is to get the tension just tight enough to prevent the axis from drifting under its own weight when it is not loaded but not any tighter than necessary to achieve that end. The correct amount of tension often occurs within a narrow range of adjustment. If you make it too tight, the knob will be harder than necessary to turn, and the frictional component will wear out faster. Be patient and do it a couple times.

Y-Axis Adjustment

The Y-axis tension adjustment is performed with essentially the same technique that's described in the X-axis adjustment setion. It's the same control mechanism. If the manipulator is operated in the standard position with the electrode clamp located right above the manipulator body, then the Y-axis doesn't typically drift as much (unless the manipulator body is tilted to the left or to the right relative to the vertical plane).

Z-Axis Adjustment

Adjusting the Z-axis is a little bit different. The z-axis is notorious for drifting, since it is subject to gravitational forces by the weight of the entire manipulator body and the load. The tension is adjusted by rotating this adjustment ring. To do that, you need a tiny flat head screwdriver. It fits in the screw located on the adjustment ring between the Y- and Z-axis control knob. There's a tiny screw on the ring, and you will need to loosen that and rotate that ring to adjust the Z-axis. Use the screwdriver to push the ring. It can be difficult to turn the ring, but if you have the screwdriver positioned so that the flat head is perpendicular to the ring, then you can use a screwdriver to push it up. With older manipulators the adjustment ring may be too tight to turn, even using the adjustment knob. If it becomes too hard to turn and you can't get it with the screwdriver, you must take the Y-axis control knob off. Be careful of all the bushings and the little nylon parts in there. They must be replaced in the same order. Once the knob is removed, then you have direct access to manipulate the ring.  

 

If you have any questions, just give us a call at (866) 606-1974 (Toll free in the USA) or email us at wpi@wpiinc.com.

  

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