Glass manufacturing apparatus and methods

A method of manufacturing a glass ribbon comprising the steps of:

• (I) providing a first pull roll apparatus including a first upstream pair of draw rolls and a second upstream pair of draw rolls;
• (II) providing a second pull roll apparatus including a first downstream pair of draw rolls positioned downstream along a draw path from the first upstream pair of draw rolls, and a second downstream pair of draw rolls positioned downstream along the draw path from the second upstream pair of draw rolls;
• (III) forming a glass ribbon with a width extending between a first edge portion and a second edge portion;
• (IV) operating the first pull roll apparatus such that at least one of the first upstream pair of draw rolls rotates to draw the first edge portion of the glass ribbon along the draw path and at least one of the second upstream pair of draw rolls rotates to draw the second edge portion of the glass ribbon along the draw path;
• (V) calculating a first downstream angular velocity of at least one of the first downstream pair of draw rolls based on a first downstream equation including a predetermined diameter of the at least one of the first downstream pair of draw rolls and a predetermined ribbon velocity of the first edge portion of the glass ribbon downstream from the second pull roll apparatus;
• (VI) calculating a second downstream angular velocity of at least one of the second downstream pair of draw rolls based on a second downstream equation including a predetermined diameter of the at least one of the second downstream pair of draw rolls and a predetermined ribbon velocity of the second edge portion of the glass ribbon downstream from the second pull roll apparatus;
• (VII) operating the second pull roll apparatus such that the at least one of the first downstream pair of draw rolls rotates at the calculated first downstream angular velocity to further draw the first edge portion of the glass ribbon along the draw path at the predetermined ribbon velocity of the first edge portion, and the at least one of the second downstream pair of draw rolls rotates at the calculated second downstream angular velocity to further draw the second edge portion of the glass ribbon along the draw path at the predetermined ribbon velocity of the second edge portion;
• (VIII) monitoring an actual velocity of the first edge portion of the glass ribbon downstream from the second pull roll apparatus and an actual velocity of the second edge portion of the glass ribbon downstream from the second pull roll apparatus;
• (IX) modifying the predetermined diameter in the first downstream equation based on the monitored actual velocity of the first edge portion such that the predetermined ribbon velocity of the first edge portion in the first downstream equation changes to substantially match the actual velocity of the first edge portion monitored during step (VIII) without substantially changing the first downstream angular velocity;
• and
• (X) modifying the predetermined diameter in the second downstream equation based on the monitored actual velocity of the second edge portion such that the predetermined ribbon velocity of the second edge portion in the second downstream equation changes to substantially match the actual velocity of the second edge portion monitored during step (VIII) without substantially changing the second downstream angular velocity.

A glass manufacturing apparatus comprising:

• a forming device configured to produce a glass ribbon including a width extending between a first edge portion and a second edge portion;
• a first pull roll apparatus including a first upstream pair of draw rolls configured to draw the first edge portion of the glass ribbon from the forming device along a draw path extending transverse to the width of the glass ribbon;
• a second pull roll apparatus including at least a first downstream roll drive device and a first downstream pair of draw rolls, wherein the first downstream pair of draw rolls are positioned downstream along the draw path from the first upstream pair of draw rolls, wherein the first downstream roll drive device is configured to rotate at least one of the first downstream pair of draw rolls to further draw the first edge portion of the glass ribbon along the draw path;
• a control device configured to calculate a first downstream angular velocity of the at least one of the first downstream pair of draw rolls based on a first downstream equation including a predetermined diameter of the at least one of the first downstream pair of draw rolls and a predetermined ribbon velocity of the first edge portion of the glass ribbon downstream from the second pull roll apparatus, wherein the control device is further configured to operate the first downstream roll drive device such that the at least one of the first downstream pair of draw rolls rotates at the calculated first downstream angular velocity to further draw the first edge portion of the glass ribbon along the draw path at the predetermined ribbon velocity;
• and
• a feedback device configured to provide the control device with a monitored actual velocity of the first edge portion of the glass ribbon downstream from the second pull roll apparatus, wherein the control device is further configured to modify the predetermined diameter in the first downstream equation based on the monitored actual velocity such that the predetermined ribbon velocity in the first downstream equation changes to substantially match the monitored actual velocity without substantially changing the first downstream angular velocity.