Method for machining workpieces and machine tool

• US 6,593,541 B1
• Filed: 11/17/2000
• Issued: 07/15/2003
• Est. Priority Date: 05/19/1998
• Status: Expired due to Fees

• Current Assignee: Bystronic Laser AG (Invico Asset Management AG)
• Original Assignee: Bystronic Laser AG (Invico Asset Management AG)
• Inventors: Herren, Peter
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US09/700,857
• Time in Patent Office: 970 Days
• Field of Search: 219/121.78, 219/121.79, 219/121.81, 219/121.85, 219/121.67, 219/121--12, 219/121.73, 219/121.75, 700/95
• US Class Current: 219/121.67
• CPC Class Codes: B23K 26/0093 combined with mechanical machining or metal-working covered by other subclasses than B23K combined welding or cutting procedures or apparatus B23K28/02
• CPC Class Codes: B23P 23/02 Machine tools for performing different machining operations lathes, e.g. capstan lathes, B23B; combined horizontal boring and milling machines B23B39/02
• CPC Class Codes: B23Q 3/15573 the tool being taken from a storage device and transferred to a tool holder by means of transfer devices
• CPC Class Codes: Y10T 483/10 Process
• CPC Class Codes: Y10T 483/17 including machine tool or component

Abstract

Laser machining is often carried out using special machines or apparatus, with the workpieces having to be finished afterwards using appropriately equipped cutting machine tools. According to the invention, a laser beam (5) is supplied on the head-stock (17) of a machine tool (13), by means of a beam control tube (12). Said beam radiates into a focussing lens (35) at an articulation point (D). Said articulation point (D) is precisely guided and held in place in a centring cone (36) with its focussing lens (35) located underneath. The laser-machining head can be removed from the headstock (17) by means of a swivel mechanism and the machine (13) can carry out cutting operations in the usual way. The laser-machining operations are carried out before the cutting work in the processing cycle, a zero-offset being provided between the laser machining and the cutting work, correcting any system errors with the help of a computer.

Claims

1. A method for two and three-dimensional machining of workpieces on a numerically controlled machine tool, more particularly a CNC machining center, by means of cutting tools and a laser machining device comprising a laser machining head, a laser source with attached beam forming means and beam guide for generating a laser beam and supplying it to the laser machining head, the laser machining head being mechanically pivotable and insertable into a tool holder of the machine tool, the laser machining head being moved during a cutting operation by a cutting tool into an inoperative/park position, comprising the steps of:

providing a tool holder capable of alternatively accepting both a cutting tool and a laser machining head for operating on a workpiece;

mounting the laser source in a vibration-free manner on a workshop floor;

supplying the laser beam to the laser machining head via a flexible beam arm with beam guide tubes and joint points to the laser machining head connected to a last beam guide tube while maintaining a constant beam guide length during movement and operation of the laser machining head;

maintaining the last beam guide tube orthogonal to a main axis of the machine tool and a next beam guide tube parallel to the main axis; and

performing a changeover operation for the tool holder between the cutting tool and the laser machining head by swivelling the last beam guide tube orthogonally in relation to the main axis and having the machine tool replace the cutting tool in the tool holder with the laser machining head (swivelling the last beam guide tube orthogonally in relation to the main axis during a changeover operation for the tool holder between the cutting tool and the laser machining head.

2. A method according to claim 1, including the laser machining steps of:

causing the laser machining head to act on the workpiece and after its use swivelling the head into a park position;

measuring the coordinates of a mark and/or opening in the workpiece produced by the laser machining head;

performing a calculated zero correction to adjust the position of the workpiece in relation to the main axis; and

performing a subsequent tool changeover and associated machining operation on the workpiece.

3. A machine tool for implementing the method according to claim 1, or 2, characterized in that the laser machining head has an optical axis having a portion fixed and coaxial to a main axis of the machine tool and includes means for directing the laser beam coaxially or laterally into the laser machining head.

4. A machine tool according to claim 3, characterized in that the laser source is coupled to a jointed arm comprising beam tubes and joints connected to the machine tool.

5. A machine tool according to claim 4, characterized in that the laser machining head includes focusing optics and is connected to a last joint of the jointed arm.

6. A machine tool according to claim 5, characterized in that the laser machining head has a clamping device which may be inserted and fixed in a tool-holding fixture of the machine tool.

7. A machine tool according to claim 6, characterized in that the clamping device is a centering cone.

8. A machine tool according to claim 3, characterized in that the laser source is axially displaceable and the machine tool includes fixedly mounted mirrors for directing the laser beam into the main axis of the machine tool and includes a headstock having a motor spindle in the form of a hollow shaft through which the laser beam is guided.

9. A machine tool according to claim 8, characterized in that the laser machining head is provided with a continuous bore with focusing optics which may be inserted and fixed in a holding fixture in the hollow shaft and which direct the laser beam coaxially to a workpiece.

10. A machine tool according to claim 7, characterized in that the laser source is flange-mounted on the machine tool and includes means to couple the laser beam into the hollow shaft.