Patent ID: 8230701

Claim:
A method for forming a fused silica glass blank, comprising: generating soot using an array of soot producing burners; directing the soot along a first direction onto a bait; collecting the soot on the bait; imparting a relative oscillatory motion having a repeat period between the array of soot producing burners and the bait along a second direction orthogonal to the first direction for a first time period equal to the repeat period while collecting the soot, the relative oscillatory motion having a starting position along the second direction; after the first time period, repeating the imparting of said relative oscillatory motion for a second time period equal to the repeat period; and before repeating the imparting, offsetting the starting position of the relative oscillatory motion by a selected distance along the second direction wherein the relative oscillatory motion has a plurality of return points over the repeat period, and wherein the return points are varying over the repeat period.