Length Measurement & Cut-to-length Control
Cut-to-length Control of Non-metal Products
While often applied in steel mills and metal processing, LSV is equally effective in the production of non-metallic goods such as wood, cardboard, foil, plastics extrusion, cable, building materials, textiles and fabrics. The image shows the LSV determining cut-to-length of corrugated paperboard sheets.
Motion Measurement at a Thin Slab Steel Mill
The steel industry needs precise length and velocity measurements from moving, red-hot steel to regulate and control production processes. In a thin slab steel mill, a strand of liquid steel is continuously poured into an ingot mold (continuous caster). The LSV is used to determine, without contacting the hot steel, the length and transport velocity (i.e., the casting speed of the slab poured) of the hot strand to be cut.
Regulating Undesired Rotational Motion in Steel Rolling Mills
At BGH’s Edelstahl Freital facility, two Polytec LSV-6000 velocimeters are used in a planetary mill to control the process. The first LSV measures the translational velocity and, thus, the length of the steel rod to achieve precision cut-off control. The second LSV measures the rotational velocity. This measurement is fed back into the drive system of the planetary mill to eliminate the rotation of the rod.
Control of Flying Tube Saws
Flying saws are being used increasingly in tube mills. In order to hit the cut-to-length value, with minimum wear to the saw blade and other mechanical components, the track speed of the flying saw must be matched with the linear speed of the tube. The LSV can measure tube speed and length directly, without the issues related to contact measurement devices, such as slippage, chatter and changing wheel diameter. The improved feedback to the flying saw results in tighter cut-to-length tolerance, better synchronization of the saw track speed to the tube linear speed, and increased saw blade life.
Length Measurement in Manufacturing of Conveyor and Drive Belts
A leading manufacturer of drive belts and conveyor belts uses several LSVs for length measurements at the cutting station. Thus, customer-specific cuts can be automated, simplifying the process significantly. The cut-to-length accuracy is independent of the belt surface and achieves a precision of 0.1%.