Laser Sensor Controls Mold Level for Aluminum Ingots

Kathleen G. Tatterson

The Reynolds Metals Co. Alabama Reclamation Operations in Muscle Shoals, Ala., processes aluminum from recycled cans, scrap from canning plants and other sources of new and used aluminum as part of the company's extensive recycling network. Photonics is now playing a part in that effort with the installation of a LaserPour aluminum mold level control system from Selcom Inc. of Southfield, Mich.

The LaserPour aluminum mold level control system ensures consistent metal head level online at Reynolds' Reclamation Operations.

Reynolds melts down the scrap metal and turns it into aluminum ingots that can weigh as much as 30,000 lb and measure up to 78 in. wide and 26 in. long. The company then ships the ingots to the main alloys plant for rolling and coating.

The company was looking for a replacement for its floating baffles as a way to ensure tighter control to lower the metal head in the aluminum ingot molds. The LaserPour system is used to ensure a consistent metal head level in the production of aluminum ingots.

"We wanted a system that would accurately control the molten metal flow and level in the ingot to ensure the correct ingot physical dimensions and grain structuring," said Julie Sheets, a reclamation metallurgist at Reynolds.

The LaserPour system comprises four of Selcom's noncontact industrial SLS 5200/300 sensors, Selcom system software, an industrial controller, a remote operator console with a Xycom industrial workstation with graphics display for human/machine communication, and four electrically driven actuators throttling the pin into the nozzle. The sensors are installed across a 300-in. trough that runs along the top of each of four ingot molds. They feature integrated sensor electronics within the head and a built-in processor for data averaging and filtering. Selcom designed the sensors, based on the principle of optical laser triangulation, for flexibility and for ease of use.

The sensors have a high-speed resolution within 0.006 in. of the measurement range, a data sampling rate of 16 kHz and a bandwidth response of 2 kHz. A dynamic laser feedback loop allows accurate measurement regardless of ambient light changes, variations in object reflectivity speed, temperature of material and general environmental conditions at the plant.