Lens grinder

摘要

A machine for cutting/grinding ophthalmic lenses has a lens spindle (11) aligned on a vertical longitudinal axis and a tool spindle (13) aligned on an angled axis in relation to the vertical axis. The lens blank (L) is chucked on the upper end of the lens spindle (11) and a tool (T) is mounted on a lower end of the tool spindle (13). One motor rotates the lens spindle (11) and the lens blank (L) about the longitudinal axis and a second motor vertically reciprocates the lens spindle (11) and the lens blank (L). A third motor rotates the tool spindle (13) and the tool about the angled axis and a fourth motor linearly horizontally reciprocates the tool spindle (13) and the tool (T). A microprocessor (63) coordinates the rotation and reciprocation of the spindles to cause the tool to cut/grind the lens blank (L) to a predetermined contour. The tool (T) has a spherical grinding surface of diameter approximating but not greater than twice the radius of the steepest lens curvature to be cut/ground. Preferably, the angled axis intersects the vertical axis with an angle of approximately 125 to 145 degrees therebetween. Also preferably, the microprocessor (63) causes the tool spindle to rotate at an angular velocity of approximately 8,000 revolutions per minute and the lens spindle to rotate at an angular velocity of approximately 20 to 150 revolutions per minute, so that the impact of the lens speed on the relative surface speed of the tool to the lens is negligible. <IMAGE>