Kohzu

Positioning is successively carried out in a specified direction from one stroke end, and [ (actual distance traveled) - (distance through which travel should be carried out) ] is measured at respective positions and then the maximum deviation within a full stroke is obtained.

Positioning is repeated 7 times at an arbitrary point from the same direction, the stop position is measured. Perform this operation on three (3) points: at the center and at both ends. Then multiply the maximum deviation of the measured deviation by 1/2. Repeatability is indicated by adding ± to one half of the maximum deviation. The load is only a corner cube placed on the center of the table.

First, positioning is carried out at one position in the positive direction, and the position is measured (L1). Next, a command in the same direction is given for position movement, and the same command in the negative direction is given for position movement, positioning in the negative direction is carried out, and then the position is measured (L1'). Then, a command in the negative direction is given for position movement, the same command in the positive direction is given for position movement from the position, positioning in the positive direction is carried out, and then the position is measured (L2). Then, this motion and measurement are repeated 7 times, and the differences between the average values of the positioning stop positions of the respective 7 times in the positive and negative directions are obtained. These measurements are made at the center of the motion and at both ends of the motion respectively, and the maximum value of the obtained values is the measurement value.

An indicator is set up at the center of the table so that it touches the surface of the baseline flat surface. Vertical displacement is, in principle, measured over the full stroke in 1 / 10 ( or 1 / 20 ) intervals.

After the position and displacement are plotted, the starting point and ending point are connected, and the sum of the maximum upward (+ ΔZ1) and minimum downward (+ ΔZ2) deviation from the baseline is defined as straightness (within the vertical plane).

The baseline flat surface is set up at the table, while the Indicator, which touches the stretch surface is fixed, and then horizontal displacement is, in principle, measured over the full stroke in 1 / 10 ( or 1 / 20 ) intervals.

After the position and displacement are plotted, the starting point and ending point are connected, and the sum of the maximum upward (+ ΔZ1) and minimum downward (+ ΔZ2) deviation from the baseline is defined as straightness (within the horizontal plane).

* The baseline slant _ shows the angle deviation between the traveling direction of the table and base stretch.

X Linear Stage

Center of the table of the stage is moved from the center position of stepping motor type X, Y, Z stages 5mm toward the motor side (to right) by motor drive, then the Indicator is put into contact with the table and the position is the reference value (zero). Backlash is defined as the value shown by the Indicator after applying a force 1 kg to the right with a push gauge and releasing it.

Swivel Stage (Goniometer)

The table is moved from the anti-motor side to the center point direction and is stopped. The position is read with an autocollimator, and then is used as a reference value. The reference value is determined, the table is pushed with a force of 1 kg in the tangential direction of the arc, motor side direction, by use of a push-pull gauge, then the gauge is released. The value of the autocollimator at this time is defined as the backlash.

Rotation Stage

The table is rotated clockwise and stopped at an arbitrary angular position which is taken as an origin. Then, a 1kg force is applied tangentially in the clockwise direction from the external portion by means of a push gauge and the push gauge is released, and the backlash is defined as the angular difference between the origin and the position, where the table stops after releasing the force.

When an off axis force (a W kg load, that is, a moment in the rolling direction at the distance l cm perpendicular to an axis, when the motion direction from the center of the table is assumed to be the axis) is applied, the table tilts. Momentum Load is defined as the tilt angle of the table per momentum unit. Units are [ arcsec / kgf-cm ].

We define this parameter as table tilting under an off table center load (load of W kg is applied to the table at a distance l cm, perpendicular to the rotation axis from the table center). Units are [ arcsec / kgf-cm ].

Set a reference point on the actual rotation axis above the table and while operating the table in the full moving range, follow the deflection of the reference point with a CCD camera. The amount of deflection is defined as the rotation center play.

If the swivel stage is ideally manufactured without any errors, an ideal rotation center does not move even if it is moved a full stroke. In reality, however, the center moves both in the vertical and horizontal directions within a circular cylinder of φ0.1mm. When two axes are combined, there exists an ideal center (1) and ideal center (2).

The distance from the reference point set for measuring the rotating center displacement to the table top face is defined as the working distance.

An error as shown in the right diagram appears in an interval of one worm wheel rotation. Error of gear cutting division = Δ1 + Δ2

When moving rotation stage from 0° to 360° or vice versa, maximum error between motion forward and motion backward is defined as lost motion.

Angle determination is successively carried out from 0° in the positive direction, and [(actual angle traveled) - (distance through which travel should be carried out)] is measured at respective positions, and then maximum deviation between the 1st motion forward and 2nd motion forward in 2 backward and forward motions is obtained.

Speed reduction ratio in the worm wheel used for our rotation stage is basically 1 / 180. This means that the gear has 180 teeth at the circumference. This defines the extent of deviation from the standard 2° 00' 00'' for each tooth.

An indicator is placed into contact in the vicinity of external periphery of the table, and a measurement is made at 36 points for every 10°.

Maximum error ( peak to peak ) is obtained. This value is the sum of deviations resulting from surface runout errors and that derive from finished table surface irregularities.

The inner diameter as a reference is provided in the main shaft. During final assembly, displacement of this inner diameter is measured with an indicator. This value is the sum of roundness deviations of the inner diameter and eccentricity, and we define this value as eccentricity.