Setting Roll Pass Lines

Assuming the caster segment is level to Earth, the following method can be used for checking the elevation of the rolls (i.e., checking the pass line) of a caster segment.

First, the L-733 or L-743 Triple Scan Laser is placed on an instrument stand so that the laser plane is approximately 6" higher than the highest elevation of the roll. It is then leveled using the built-in level vials.

Next, an A-1532 Single-Axis Target (A-1519, A-1519HR, A-1531 or A-1533 can also be used) is placed on the roll with the highest elevation and is zeroed out by pressing the zero button. If more than one target is going to be used for the measurements, then those targets are also zeroed on the same exact point as the first target.

Finally, after zeroing the target (or targets), simply place it on another roll, or point on the same roll, and the elevation relative to the first roll will be displayed. This is a very quick way of checking both the actual elevations and the parallelism of the rolls to each other. The A-1533 can detect up to 3" of elevation changes. Since the readings are live, the rolls can be adjusted to the correct elevation using the readout as a digital indicator.

If there are elevation changes greater than 3", the BASE mode on the target can be selected, which will display the actual reading from the base of the target to where the laser is hitting it. Precision spacers, either provided by Hamar or the end user, are used to span the distance from the roll or other surface to the laser plane. Add the spacers to the reading in the BASE mode and the actual dimension from the roll or other surface to the laser plan is determined.

If the segment has not been leveled, then the L-733 or L-743 can still be used to check the elevations. The procedure is almost the same as above with the only exception being that the laser is "bucked-in" to the 3 reference points on the segment. The reference points can be the segment mounting pads or 3 of the rolls themselves. The bucking-in process is very similar to that of optics.

Checking Parallelism of Caster Segment Location Pins

This procedure is for checking the upper and lower locating pins for the segments in the mill itself.

First, a fixture for holding the laser is placed over the mill at the top set of pins. The laser is placed approximately in the center between the two pins and leveled.

Next, targets are fixtured on the locating pins horizontally and are squared to one of the vertical laser planes using the Top Dead Center Method. Then the vertical laser plane is adjusted using the azimuth adjusting knob so that the same readings appear on both targets. This means the laser is parallel to the locating pins and is also plum to Earth since the laser has been leveled.

Finally, a measuring target is zeroed on one of the reference pins and placed on of the lower locating pins. Again using the Top Dead Center Method to square the target to the laser beam, the resulting measurement of the first lower pin is how far out of plumb it is to the upper pin. The difference between the 2 lower-pin measurements is a measure of how far out of parallel the upper pins are to the lower pins. Since the targets provide live alignment data, they can then be used to adjust the pins, if possible, to bring them into alignment.

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