Online width measurement and alignment

The problem

Camera systems with backlit illumination are often used to measure sheet width online and to provide closed loop feedback to alignment systems. However, these systems can only detect the edges of a sheet or extrusion using a shadow principle and are not able to measure the cross sectional profile of the product. This is a major problem where the product needs to be aligned according to the positions of features on the product, eg treads shoulders, rather than the edges. In addition conventional backlit camera systems:

 

Must be mounted high above the line and are problematic where access is limited around production equipment

Cannot be used if the product is on a continuous belt conveyor or is produced on a backing sheet

Cause alignment errors when edges are feathered

 

The solution

A "Smart" 3D sensor based on laser sheet of light technology with an on board processor running Sigmavision's TEPS™ extrusion profiling firmware. The "Smart" 3D sensor is mounted above the extrusion conveyor and a line of laser light projected onto the product's top surface. The profile is measured using two high resolution cameras generating a dynamic accuracy <0.2mm. Read more