Metals Processing

Plate Mills

Optimize Crop, Shear and Cut Length of Plates

The plate mill can represent the only point in the process where the final dimensional quality of the product can be measured and controlled prior to final shipment. That's why it's important to have accurate length measurements at this critical stage of the manufacturing process.

Plate mills roll the heavy plate to the proper thickness and then square the ends and divide the plate into the desired length. LaserSpeed® Pro non-contact gauges are used at three locations on a plate mill. First, a gauge is mounted upstream of the shear to measure the overall length of the plate. This information helps to determine the best way to divide the plate into lengths required by the end customer, while leaving as little scrap as possible.

Controlling Cut-to-Length
The plate is then fed into the crop shear to square up the front and back ends. A PLC acquires the shape of the plate’s front end from a line scan camera and the position of the plate from the LaserSpeed Pro gauge. From these two pieces of information, a profile of the front and tail end can be established and the optimum crop can be determined.

The LaserSpeed Pro gauge continues to provide plate position information, so the PLC can make an accurate front-end crop. Once the plate is cropped, the PLC continues to use the position information from the non-contact gauge to cut the plate into target lengths according to the customer requirements. Note that the plate can be jogged back and forth (without slippage errors) to achieve the optimum cut length.  Use of the LaserSpeed Pro gauge determines the optimum use of the plate to minimize waste.

Improving Yields and Minimizing Scrap
A third LaserSpeed Pro gauge is placed just downstream of the shear and measures plate position once the tail end passes the gauge upstream of the shear. The position information from the downstream gauge is used to make the final tail-end crop. The non-contact gauge greatly improves the yield of the plate mill and minimizes scrap because of the slippage that occurs between the plate and the encoder rollers.

LaserSpeed Pro gauges can provide plate position to within a few millimeters, whereas a encoder roller can have errors up to 20 mm or more.

Check out our LaserSpeed Pro gauging solution below.