Abstract: A gob formation device and method for improved production of molten glass preforms for use in the precision glass molding of optical glass elements. The device is a dispensing tip which is attached to a stem extending from a working crucible containing a supply of molten glass. The dispensing tip includes a longitudinal bore through which the molten glass flows, and a downwardly projecting gob formation surface located at a distal end of tip. The downwardly projecting gob formation surface is preferably convex which aids in achieving greater uniformity of mass in the gob formation process as well as improving preform internal quality.

Abstract: Optical glass preforms for use in subsequent molding processes for the production of lenses are produced which have a controlled peripheral edge wall geometry. Gobs of molten glass of predetermined weight and volume are dripped onto a lower mold surface. A pressing head including a sleeve and a plunger are lowered such that the sleeve surrounds the gob. The plunger is then depressed such that the upper mold surface of the plunger resides in a predetermined elevation above the lower mold surface thereby forcing the gob to conform to the cavity created within the sleeve and between the upper and lower mold surfaces. In such manner the sleeve serves as a form or exterior boundary for the resultant preform such that a preform is produced which requires no grinding or polishing prior to its use in subsequent molding operations.

Abstract: A method of making gob preforms for the optical quality lens molding comprising: i) ejecting a measured gob molten glass through an exit in a stem of the container of a supply of molten glass; ii) allowing the gob to settle under gravity from the exit to a catching tool while heating the gob and the catching tool; and iii) continuing to heat the gob and tool until the gob is round.