SYSTEM FOR CONTROLLING A MACHINE TOOL

Abstract

The invention relates to a system for a method for controlling a machine tool with at least one replaceable tool and a workpiece, especially a mill blank, and for a method for machining the workpiece, which machine tool comprises a robot arm movable along at least 2, especially at least 3 space axes in an area of motion, which carries and moves at least one workpiece, eventually via a workpiece holder, with a control unit for controlling the machine tool. The machine tool (52) includes a sensor (46), especially a space-fixed optical sensor located thereon or associated thereto, and the detection range (42) of which overlaps the area of motion at least partially for detection of a code on the machine tool.

Claims

1. A system for a method for controlling a machine tool with at least one replaceable tool and a workpiece, and for a method for machining the workpiece, wherein the machine tool comprises a robot arm movable in an area of motion along at least 2 spatial axes, which robot arm carries, guides and moves at least one workpiece, with a control unit for controlling the machine tool, wherein the machine tool (52) comprises or is associated with a sensor (46), having a detection range (42) that at least partially overlaps an area of motion of the machine tool, wherein a front face (34) of a tool shaft (22) of the at least one replaceable tool (10) is provided with a code (36), wherein the at least one replaceable tool (10) is moved by the robot arm (44) in the detection range (42), wherein when detecting the code (36) by the sensor (46), the code (36) is passed to a control unit (54) for identification of the tool (10), and wherein the control unit (54) is configured to perform identification of the tool (10) for controlling the machine tool (52) for machining, the machining being adapted to the identity of the tool (10).

2. The system according to claim 1, wherein the workpiece is in the form of a mill blank, wherein the robot arm is movable along at least 3 spatial axes wherein the workpiece is held by a workpiece holder, and wherein the sensor is a space-fixed optical sensor.

3. The system according to claim 1, wherein the tool (10) is supported on a gripper or an accommodation (48) of the robot arm (44) and wherein the front face (34) of the tool shaft (22) extends in the detection range (42) of the sensor (46).

4. The system according to claim 1, wherein the tool shaft (22), at an end facing away from a work area (18) of the tool (10) conically tapers towards the front face (34), such that the conical portion (32) of the tool shaft (22) forms an insertion bevel, which facilitates insertion of the tool (10) into a clamping chuck of a tool spindle (50) of the machine tool (52).

5. The system according to claim 4, wherein an angle (38) of the conical portion (32) is between 10 and 30, or between 15 and 25, in relation to the rotational axis (20) of the tool shaft (22).

6. The system according to claim 5, wherein the length of the conical portion (32) of the tool shaft (22) is between 5% and 20%, or between 7% and 15%, of the total length of the tool shaft (22) including the conical portion (32) of the tool shaft.

7. The system according to claim 6, wherein surface area of the front face (34) is between 50% and 70% of the cross-sectional area of the cylindrical portion (30) of the tool shaft (22), or at least 60% of the cross-sectional area of the cylindrical portion (30) of the tool shaft (22).

8. The system according to claim 1, wherein the front face (34) of the tool shaft (44) comprises a surface generated by line-by-line surface treatment.

9. The system according to claim 8, wherein the surface treatment is by treatment with a laser tool.

10. The system according to claim 1, wherein the front face (34) of the tool shaft (44) is circular-shaped and the code (52) on the front face (34) of the tool shaft (44) occupies a rectangular-shaped surface (36).

11. The system according to claim 1, wherein the code (36) is a monochrome code.

12. The system according to claim 11 wherein the monochrome code is a Data Matrix Code.

13. The system according to claim 1, wherein the code (36) is applied to the center of the front face (34) of the tool shaft (22).

14. The system according to claim 1, wherein between a circular rim of the front face (34) of the tool shaft (22) and outer corners of the rectangular-shaped surface, which is occupied by the code (36) on the front face (34) of the tool shaft (22), in the radial direction in relation to the rotational axis (20) of the tool shaft (22), there is equal distance towards all sides, which is more than 3% of the radius of the front face (34) of the tool shaft (22).

15. The system according to claim 1, wherein the surface portions surrounding the rectangular-shaped code (36) on the front face (34) of the tool shaft (22) remain unused for applying other codes or information.

16. The system according to claim 1, wherein the code (36) is applied onto the front face (34) of the tool shaft (22) by laser tool machining or laser engraving.

17. The system according to claim 1, wherein an ID is incorporated into the code (36) unequivocally identifying the tool (10).

18. The system according to claim 1, wherein an ID is incorporated into the code (36) unequivocally identifying the lot of the tool (10).

19. The system according to claim 1, wherein an ID is incorporated into the code (36) unequivocally identifying the type of the tool (10).

20. The system according to claim 19, wherein the code identifies the grain size of a milling cutter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further advantages, details and features will arise from the following description of several working examples by way of the figures, wherein:

[0039] FIG. 1 is a lateral view of a tool and a bar code for explanatory purposes;

[0040] FIG. 2 is a perspective view of a tool according to the invention;

[0041] FIG. 3 is an enlarged representation of a detail of FIG. 2;

[0042] FIG. 4 is a perspective view of the system according to the invention.

DETAILED DESCRIPTION

[0043] The tool 10 represented in FIG. 1 comprises a work area 18, which, for example, may be provided with diamonds. A shaft 22 is provided at the opposite end of the tool 10. A ring 24 is provided there between on the tool 10, which may be seen from FIG. 2, with two adjacent annular grooves 12 and 14. They are intended to be maintained in an accommodation of the robot arm 44, which robot arm may be seen from FIG. 4, or to be maintained in an appropriate gripper. From FIG. 4, it may also be seen that, in this position of the shaft 22, the shaft of the tool 10 is exposed.

[0044] According to FIG. 3, the shaft 22 is provided with a code 36, preferably a Data Matrix Code, which extends as a two-dimensional code in rectangular or square shape on the front face 34 of the tool shaft 22. Starting from ring 24, the essentially cylindrical shaft 22 of the tool 10 proceeds from the cylindrical portion 30, constituting the predominant part of the length of the tool shaft 22, to the conical portion 32, which thus forms the insertion bevel.

[0045] In FIG. 1 a (one dimensional) bar code 16 is representedfor explanatory purposes only. However, when applying such a code onto the shell surface, i.e. the cylindrical portion 30 of the tool shaft 22, damages of the code may arise due to abrasion or impression marks of the clamping chuck of the spindle 50, which may be seen in FIG. 4, impairing safe reading of the code. Hence, such a solution suffers from disadvantages.

[0046] The circular front face 34 extends at the front face and thus at the end of the conical portion 32, which front face, according to the invention, carries the code 36, which unequivocally identifies the tool 10. Areas, which do not carry any identification, and which areas are referred to as the so called resting zones extend around the code 36.

[0047] The rectangular-shaped or square code 36 is applied exactly centered, in relation to the rotational axis 20, which is represented in FIG. 2. With this approach, and with the resting zone which uniformly extend around the surface occupied by the code 36 and which are free of any identification, safe reading of the code 36 by the sensor 46, which is represented in FIG. 4, will be assured.

[0048] The surface on the front face 34 of the tool shaft 22 available for application of the code 36, may be enlarged by shortening the conical portion 32 (as viewed along the rotational axis 20) or may also be enlarged by reducing the cone angle 38, if required, such as already set forth above.

[0049] From FIG. 4, a possible basic embodiment of a machine tool 52 according to the invention may be seen. The sensor or the camera 46, respectively, is applied non-displaceably above a milling room and is separated therefrom by a door not represented. The door opening does not interfere with the detection range 42 (the optical axis of which is represented in FIG. 4) of the camera 46.

[0050] For the sake of better visibility, it may be seen from FIG. 4, how a code, which is also present on the front face of a workpiece 40 to be processed, which is held by a robot arm 44, is detected by the sensor 46 according to the invention. The detection range or the optical axis 42 thereof, respectively, is represented by the dash-dot line.

[0051] It is to be understood that detection of the two tools 10 to be recognized in FIG. 4 on the front face according to the invention is basically done in the same way, i.e. by turning the robot arm 44 by 90 degrees to the right, thus successively passing the two tools 10 maintained in the two accommodations of the accommodation device 48 to the detection range of the sensor or camera 46. When positioned appropriately, the sensor or the camera 46 may then detect and identify the code 36 and thus the respective tool 10.

[0052] Below the robot arm 44, a tool spindle 50 may be seen. It is for keeping a tool 10 clamped via a clamping chuck. For this purpose, the tool 10, with its shaft 22 will be introduced into a clamping chuck on the spindle 50, and will be clamped therein, via the robot arm 44, the clamping chuck not being represented in FIG. 4 for the sake of clarity. For this purpose, the robot arm 44 comprises two accommodations for the tools 10. The tools 10 may then optionally be inserted into the clamping chuck of the tool spindle 50, which means a tool 10 immediately to be used will be clamped into the clamping chuck of the spindle 50, whereas the tool not used in the meantime remains in one of the two accommodations of the accommodation device 48.

[0053] Basically, the accommodations of the accommodation device 48 are U-shaped and engage into the annular grooves 12 or 14 (cf. FIG. 2). Such a bearing exposes the shaft 22 of the respective tools 10. The robot arm 44 is formed as having five axes and is able to turn the accommodation device 48 such that the shaft 22 is located in the detection range 42. In this position, the sensor or the camera 46, respectively, may read the code attached thereto, and passing it to the control unit 54 for identification of the tool 10.