Planing-polishing apparatus and method using femtosecond pulsed laser
Assignee21Th Century Co., Ltd
InventorsSung Hwan Kim, Hyoung Shik Kang, Dong Bin You
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Abstract
Proposed is a planing-polishing apparatus 1 using a femtosecond pulsed laser and performing polishing of a planar workpiece to reduce surface roughness of the workpiece after performing planing of the workpiece using a femtosecond pulsed laser beam.
Claims18
A planning-polishing apparatus using a femtosecond pulsed laser and performing polishing of a planar workpiece to reduce surface roughness of the workpiece after performing planning of the workpiece using a femtosecond pulsed laser beam, the apparatus comprising:
- a position fixing unit comprising a stage on which a workpiece is seated, a fixing jig for fixing the workpiece on the stage, and a transport means for moving the stage along X and Y axes, such that a surface of the workpiece is machined;
- a surface shape measurement unit digitalizing a surface shape of the workpiece into surface shape data by measuring heights at a plurality of measurement points on the surface of the workpiece and transmitting the surface shape data so that surface flatness of the workpiece is measured;
- a laser machining unit performing a planning process of planarizing for cutting only a convex portion of a machining area by selectively irradiating the machining area with a femtosecond pulsed laser beam in accordance with the surface shape data obtained from the surface shape measurement unit and, after the planning process, a polishing process of reducing irregularities formed on the surface of the workpiece by irradiating the irregularities with a femtosecond pulsed laser beam having a lower power level than the laser beam used in the laser planning step, wherein the surface shape data measured by the surface shape measurement unit is data regarding displacements along a Z-axis at the plurality of measurement points;
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- a controller converting the surface shape data into multiple-plane data, by which areas protruding to the same heights from virtual cross-sectional planes drawn by connecting points having the same heights from among the plurality of measurement points are determined to be planning areas, with the virtual cross-sectional planes being maintained to be arranged at predetermined distances in a height direction, transmitting machining parameters input for the planning process in accordance with the multiple-plane data, and controlling an operation of the laser machining unit.
A planning-polishing method using a femtosecond pulsed laser and performing laser polishing of a planar workpiece to reduce surface roughness of the workpiece after performing laser planning to planarize a surface of the planar workpiece using a femtosecond pulsed laser beam, the method comprising:
- a machining preparation step of locating and fixing the workpiece at a machining origin on a stage in order to machine a surface of the workpiece;
- a surface shape measurement step of digitalizing a surface shape of the workpiece into surface shape data by measuring heights at a plurality of measurement points on the surface of the workpiece using a laser displacement sensor;
- a step of converting the surface shape data obtained by the surface shape measurement step into multiple-plane data in which virtual cross-sectional planes drawn by connecting points having same heights from among the plurality of measurement points are arranged at predetermined distances, determining areas protruding to same heights from the cross-sectional planes as planning areas, and determining and inputting machining parameters for a planning process;
- a laser planning step of planarizing for cutting only a convex portion of the surface of the workpiece by irradiating, by a laser machining unit, the planning area determined from the surface shape data with a laser beam in a predetermined pattern to which the machining parameters are applied;
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- a laser polishing step of reducing irregularities formed on the surface of the workpiece by radiating a femtosecond pulsed laser beam having a lower power level than the laser beam used in the laser planning step, thereby reducing surface roughness of the workpiece.
Dependencies are inferred from the claim text.