Distortion measurement in casting

A method for monitoring cross-sectional distortion in a relatively rigid cast product movable along the path and having ideally a predetermined rectangular cross-section, the product being subject during motion along the path to wavering movement transverse to the path, said method utilizing two contact elements and comprising the steps of:

• (a) supporting the contact elements on different sides of the workpiece path independently movable toward and away from the workpiece moving along the path and oriented to face different edges of the workpiece;
• (b) biasing the contact elements against opposed diagonal corners of the cast product, the edges being defined by intersections between exterior surfaces of the casting without said impingement substantially influencing workpiece temperature;
• (c) said biasing step comprising applying a biasing force sufficient to facilitate continuous riding impingement of the contact elements on the edges of the product while limiting biasing force to a level sufficiently low to avoid any substantial deformation of the cross-sectional shape of the cast product due to impingement of the contact elements;
• (d) producing an electrical signal representing the spacing between the contact elements, the electrical signal indicating distortion of the cross-sectional shape of the cast product independently of absolute thickness dimension of the product;
• (e) producing an indication when the electrical signal deviates outside a predetermined range of values.

A method utilizing two contact elements for monitoring cross-sectional distortion in a relatively rigid cast product movable along a path and having ideally a predetermined rectangular cross-section, the product being subject during motion along the path to wavering movement transverse to the path, said method comprising the steps of:

• (a) mounting each contact element facing diagonally opposed corners of the cast product as it moves along the path, said mounting rendering the contact elements independently movable toward and away from the workpiece path;
• (b) applying a biasing force sufficient to facilitate continuous riding impingement of the contact elements on the cast product while avoiding substantial temperature change of the workpiece resultant on said impingement and limiting biasing force to a level sufficiently low to avoid any substantial alteration of the cross-sectional shape of the cast product due to impingement of the contact elements;
• (c) facilitating, by means of said mounting and biasing steps, said contact elements to move transversely with respect to the workpiece path to track wavering motion of the cast product in response to said wavering motion;
• (d) producing a single electrical signal representing the relative position of both contact elements, said electrical signal indicating distortion of said cross-sectional shape of said cast product, independently of said wavering, and
• (e) producing an indication when said electrical signal deviates outside a predetermined range.

A casting system comprising:

• (a) a vertical mold adapted for accommodating molten metal for passage downwardly through the mold and casting it into a predetermined shape, said mold having a rectangular cross-sectional configuration defining the peripheral shape of the product to be cast, the location and orientation of said mold also defining a downwardly extending workpiece flow path along which the cast product passes subsequent to emergence from the mold, the cast product being subject during motion downwardly along the path, to wavering movement transverse to the path;
• (b) support structure fixed to relative to the path;
• (c) first and second guide arms movably mounted to said support structure, each arm extending on a different side of the path;
• (d) first and second contact elements connected respectively to said first and second arms and oriented to face inwardly toward diagonally opposed dihedral edges of the cast product moving along the path said contact elements having a contact area which is small relative to the area of a side portion of the workpiece;
• (e) means coupled to the guide arms for biasing the contact elements against said diagonally opposed edges of said cast product, said edges being defined by dihedral angle intersections between exterior surfaces of said cast product, said bias means applying a biasing force sufficient to facilitate continuous riding of the contact elements on said edges of the cast product while limiting biasing force to a level sufficiently low to avoid any substantial alteration of the cross-sectional shape of the cast product due to impingement of the contact elements, said bias means, guide arms and support structure cooperating to facilitate said contact elements to move independently transversely to said path to track wavering motion of the cast product in response to said wavering motion;
• (f) a single transducer simultaneously coupled between said guide arms for producing an electrical signal representing the spacing between the contact elements, said electrical signal indicating distortion of said cross-sectional shape of said cast product independently of absolute thickness dimension of the product, and of said wavering motion and
• (g) means responsive to said electrical signal for indicating when said electrical signal deviates outside a predetermined range.