US 4,083,272 A · Omega-X micromachining system

Abstract

A micromachining tool system with X- and omega-axes is used to machine spherical, aspherical, and irregular surfaces with a maximum contour error of 100 nonometers (nm) and surface waviness of no more than 0.8 nm RMS. The omega axis, named for the angular measurement of the rotation of an eccentric mechanism supporting one end of a tool bar, enables the pulse increments of the tool toward the workpiece to be as little as 0 to 4.4 nm. A dedicated computer coordinates motion in the two axes to produce the workpiece contour. Inertia is reduced by reducing the mass pulsed toward the workpiece to about one-fifth of its former value. The tool system includes calibration instruments to calibrate the micromachining tool system. Backlash is reduced and flexing decreased by using a rotary table and servomotor to pulse the tool in the omega-axis instead of a ball screw mechanism. A thermally-stabilized spindle rotates the workpiece and is driven by a motor not mounted on the micromachining tool base through a torque-smoothing pulley and vibrationless rotary coupling. Abbe offset errors are almost eliminated by tool setting and calibration at spindle center height. Tool contour and workpiece contour are gaged on the machine; this enables the source of machining errors to be determined more readily, because the workpiece is gaged before its shape can be changed by removal from the machine.

Claims18

Dependent claims

A micromachining tool comprising:

means for rotating a workpiece;
a tool bar carrying a tool bit at an end thereof for cutting the workpiece;
a first slide for moving the tool bar in a direction perpendicular to the plane of the workpiece;
a second slide mounted on the first slide aligned in a direction parallel to the plane of the workpiece;
means associated with the second slide for swinging the tool bar about a pivot point located near the end thereof remote from the tool bit and on a line parallel to an axis perpendicular to the axes of the first and second slides;
and
means for moving the pivot point along an arc surrounding the perpendicular axis at the same time the tool bar is swinging on the pivot point.

4 more elements

A micromachining tool for machining spherical, aspherical, and irregular surfaces and having a machine base, Z-axis slideways on the machine base, a Z-axis slide supported on the Z-axis slideways, X-axis slideways on the Z-axis slide, an improved main air-bearing spindle mounted on a raised section of the machine base, a spindle drive motor mounted on a motor base and connected to the main air-bearing spindle by a torque-smoothing pulley fixed to the shaft of the drive motor, a vibrationless rotary coupling fixed on a driven side to the shaft of the main air-bearing spindle and on a driving side to a pulley supported from the motor base, and a belt connecting the pulleys, the micromachining tool comprising:

an eccentric mechanism mounted on the Z-axis slide and having a lower eccentric adjustment guide supported rotatably by an eccentric mechanism housing, an upper eccentric adjustment engaging the lower eccentric adjustment guide and slidable with respect thereto, a tool bar end bearing plate supported by the upper eccentric adjustment guide, and an eccentric reference ball resting adjustably on the cylindrical column;
means for connecting the lower eccentric adjustment guide to a rotary table fixed to the Z-slide and the eccentric mechanism housing which rotates the lower eccentric adjustment guide;
a hollow tool bar, parallelepipedal in shape and having one end clamped adjustably in an open-ended trough in the tool bar end bearing plate, a tool head attached adjustably to its other end and mounting a tool bit for cutting the workpiece;
a linear air bearing having upper and lower halves which together form a hollow parallelepiped having means mounted therein for supporting a point near an end of the tol bar on all sides, the halves being fastened together by a rocker arm bearing against an edge of the upper half via a rocker ball trapped between the upper half and the rocker arm and cap screws in the rocker arm which pass through holes in the upper half and have threaded engagement with the lower half whereby the halves do not contact each other and the upper half may rotate in an arc having as its center of rotation the center of the rocker ball, and a cylindrical stub projecting pendently from the lower half;
and
a pivot bearing rotatably supporting the cylindrical stub projecting from the lower half, the pivot bearing itself being fixed to the X-axis slide and movable therewith.

3 more elements

Dependencies are inferred from the claim text.

Omega-X micromachining system

Life of this patent

Omega-X micromachining system

Life of this patent

Abstract

Claims18