Laser machining method and apparatus therefor

• US 20030183608A1
• Filed: 03/13/2003
• Published: 10/02/2003
• Est. Priority Date: 03/28/2002
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Yamazaki, Etsuo, Suzuki, Kazuhiro, Tokito, Hiroaki
• Granted Patent: US 6,870,130 B2
• Time in Patent Office: Days
• US Class Current: 219/121.83
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 26/0884 in at least in three axial directions, e.g. manipulators, robots
• CPC Class Codes: B23K 26/10 using a fixed support , i.e. involving moving the laser beam

Abstract

An apparatus and a method for laser machining with a gap or tracing control, capable of shortening time required for moving a machining head from a machining end point of one machining shape to a machining start point of next machining shape. The laser machining is performed with the gap or tracing control in which a gap amount between the machining nozzle and the workpiece is controlled to be constant. Driving of a Z-axis is started at a predetermined velocity when the machining nozzle reaches a machining end point of one machining shape. In the drive of the Z-axis, when the Z-axis is driven by a predetermined amount, driving of an X-axis and a Y-axis is started so that the machining nozzle moves to the next machining start point by rapid traverse. A direction of driving of the Z-axis is reversed at a middle point between the machining end point and the machining start point. The driving of the Z-axis may be discontinued at a retreated point. When the gap amount reaches a predetermined amount, the gap control is started. A length of the motion path from the machining end point to the machining start point is made shorter and frequency of stopping/switching operation of the gap control axis and the machining feed axes is reduced to shorten a time required for the transition to the machining start point of the next machining shape.

Claims

1. A laser machining apparatus for machining a workpiece by irradiating a laser beam from a machining nozzle comprising:

a sensor for detecting a gap amount between the machining nozzle and the workpiece;

first driving means for driving a gap control axis to be controlled such that the gap amount detected by said sensor is maintained to a predetermined value in machining;

second driving means for driving machining feed axes to move the machining nozzle relative to the workpiece along a predetermined machining shape in machining; and

a controller for controlling said first and second driving means, to start driving of the gap control axis so that the machining nozzle moves away from the workpiece at a machining end point of one machining shape, and to start driving of said machining feed axes so that the machining nozzle moves to a machining start point of a next machining shape in driving the gap control axis when the gap control axis is driven by a predetermined amount or for a predetermined time.

2. A laser machining apparatus according to claim 1, wherein said controller starts the driving of the machining feed axes when the gap amount detected by said sensor reaches a predetermined value.

3. A laser machining apparatus according to claim 1, wherein said controller determines a motion amount of the gap control axis from the start of driving of the gap control axis and starts the driving of the machining feed axes when the motion amount of the gap control axis reaches a predetermined value.

4. A laser machining apparatus according to claim 1, wherein said controller controls the driving of the gap control axis so that the machining nozzle moves close to the workpiece before coordinate position of the machining feed axes reach a coordinate position of the machining start point of the next machining shape.

5. A laser machining apparatus according to claim 4, wherein said controller reverses a direction of the driving of the gap control axis when the coordinate position of the machining feed axes reach a vicinity of a middle point between the machining end point of one machining shape and the machining start point of the next machining shape.

6. A laser machining apparatus according to claim 4, wherein said controller discontinues the driving of the gap control axis when the coordinate position of the gap control axis reaches a retreated position, and continues driving of the gap control axis in a reverse direction when a motion amount of the machining feed axes during the driving of the gap control axis becomes approximately equal to a remaining motion amount to the machining start point of the next machining shape.

7. A laser machining apparatus according to claim 1, wherein said controller starts control of the gap control axis such that the gap amount is maintained to the predetermined value when the gap amount becomes equal to or less than a predetermined allowable value after the coordinate position of the machining feed axes reaches the coordinate position of the machining start point.

8. A laser machining method for machining a workpiece with a laser beam from a machining nozzle by controlling a gap control axis such that a gap amount between the machining nozzle and the workpiece detected by a sensor is maintained to a predetermined value, and driving machining feed axes so that the machining nozzle moves relative to the workpiece along a predetermined machining shape, said method comprising:

starting driving of the gap control axis such that the machining nozzle moves away from the workpiece at a machining end point of one machining shape;

starting driving of the machining feed axes so that the machining nozzle moves to a machining start point of a next machining shape in driving the gap control axis when the gap control axis is driven by a predetermined amount or for a predetermined time; and

reversing a direction of the driving of the gap control axis in a vicinity of a middle point between the machining end point of one machining shape and the machining start point of the next machining shape, to position the machining nozzle at the machining start point.

9. A laser machining method for machining a workpiece with a laser beam from a machining nozzle by controlling a gap control axis such that a gap amount between the machining nozzle and the workpiece detected by a sensor is maintained to a predetermined value, and driving machining feed axes to move the machining nozzle relative to the workpiece along a predetermined machining shape, said method comprising:

starting driving of the gap control axis such that the machining nozzle moves away from the workpiece at a machining end point of one machining shape;

starting driving of the machining feed axes so that the machining nozzle moves to a machining start point of a next machining shape in driving the gap control axis when the gap control axis is driven by a predetermined amount or for a predetermined time;

discontinuing the driving of the gap control axis when coordinate position of the gap control axis reaches a retreated position; and

resuming the driving of the gap control axis in a reverse direction such that the machining nozzle moves close to the workpiece when a motion amount of the machining feed axes during the driving of the gap control axis becomes approximately equal to a remaining motion amount to the machining start point of the next machining shape, to position the machining nozzle at the machining start point.

10. A laser machining method for machining a workpiece with a laser beam from a machining nozzle by controlling a gap control axis such that a gap amount between the machining nozzle and the workpiece detected by a sensor is maintained to a predetermined value, and driving machining feed axes to move the machining nozzle relative to the workpiece along a predetermined machining shape, said method comprising:

starting driving of the gap control axis such that the machining nozzle moves away from the workpiece at a machining, end point of one machining shape, and starting driving of the machining feed axes so that the machining nozzle moves to a machining start point of a next machining shape simultaneously with the start of driving the gap control axis; and

reversing a direction of the driving of the gap control axis in the vicinity of a middle position between the machining end point of one machining shape and the machining start point of the next machining shape, to position the machining nozzle at the machining start point.