MACHINING SYSTEM FOR WORKPIECE MACHINING

Abstract

A machining system for workpiece machining includes a machining cell, to which a workpiece holder for fixing a workpiece, a machining head for machining the workpiece and a robot for workpiece cleaning are assigned, wherein the robot has an articulated robot arm which is mounted with an initial section on a machine frame connected to the machining cell and which is provided at an end section remote from the initial section with a nozzle, which is designed to provide a jet of compressed air, a joint being arranged between the initial section and the end section, wherein the joint is provided with a pneumatic drive for providing a relative movement between the initial section and the end section.

Claims

1. A machining system for machining of a workpiece, comprising a machining cell, to which a workpiece holder for fixing a workpiece, a machining head for machining the workpiece and a robot for workpiece cleaning are assigned, wherein the robot has an articulated robot arm which is mounted with an initial section to a machine frame, which machine frame is connected to the machining cell, wherein the robot arm is provided at an end section remote from the initial section with a nozzle, which nozzle is designed to provide a jet of compressed air and wherein a joint is arranged between the initial section and the end section, wherein the joint is provided with a pneumatic drive for providing a relative movement between the initial section and the end section.

2. The machining system according to claim 1, wherein the machine frame is arranged in the machining cell and that the workpiece holder and/or the machining head are coupled to the machine frame.

3. The machining system according to claim 1, wherein the machine frame is arranged outside the machining cell and comprises a workpiece changing station, and wherein the initial section of the robot arm is arranged above the workpiece changing station on the machine frame.

4. The machining system according to claim 1, wherein the robot is assigned an electronic control, a first valve module which is connected to the electronic control and to the pneumatic drive a second valve module which is connected to the electronic control and to the nozzle, wherein the joint is assigned a sensor system for detecting a joint position, which sensor system provides a sensor signal to the electronic control, the electronic control controls the first valve module using the sensor signal.

5. The machining system according to claim 4, wherein the first valve module is arranged on the joint and the second valve module is arranged on the machine frame or wherein the first valve module and the second valve module are arranged on the machine frame.

6. The machining system according to claim 4, wherein the electronic control comprises a human machine interface for a user input, wherein the electronic control stores a joint position upon a trigger signal of the human machine interface.

7. The machining system according to claim 6, wherein the human machine interface is arranged at the end section of the robot arm and wherein the electronic control distinguishes between at least two different trigger signals of the human machine interface.

8. The machining system according to claim 1, wherein the nozzle is a compressed-air nozzle with adjustable jet cross section or comprises a set of compressed-air nozzles from the group: point-jet nozzle, fan nozzle, deflection nozzle, with different jet cross sections.

9. The machining system according to claim 1, wherein the robot arm is surrounded by a protective hose made of flexible material.

10. The machining system according to claim 9, wherein a compressed air inlet for providing an overpressure with respect to an environment of the robot arm is assigned to a spatial volume delimited by the protective hose.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] An advantageous embodiment of the invention is shown in the drawing. Here shows:

[0019] FIG. 1 a strictly schematic overview of a processing system,

[0020] FIG. 2 a front view of an end section of the robot arm with a sensor system associated with the joint,

[0021] FIG. 3 a rear view of the end section of the robot arm according to FIG. 2 with a sectional view of the pneumatic drive, and

[0022] FIG. 4 a variant of a nozzle for the robot arm according to FIGS. 1 to 3.

DETAILED DESCRIPTION

[0023] A machining system 1 shown purely schematically in FIG. 1 is designed as a milling center and enables a workpiece 2 to be machined. For this purpose, the machining system 1 comprises a box-shaped machine frame 3, to which a robot 4, a machining head 5, a workpiece carrier plate 6 and a workpiece lock 7 are attached.

[0024] The machine frame 3, which is shown only schematically, is provided with planking on all side surfaces in a manner not shown in greater detail, so that a spatial section is formed which is sealed off from an environment of the machining system 1 and which can also be referred to as a machining cell 8.

[0025] The robot 4 has a base-like initial section 21 that is fixedly attached to an upper surface of the machine frame 3. Connected to the initial section 21 is a robot arm 22 which, purely by way of example, comprises a first arm part 28, a second arm part 29, a third arm part 30 and a fourth arm part 31, as well as associated joints 33, 34, 35 and 36 for the articulated connection of respectively adjacently arranged arm parts 28, 29, 30 and 31. In this case, the fourth arm part 31 forms, purely by way of example, the end section of the robot arm 22 and is provided at the end with a nozzle 23. For reasons of clarity, all joints 33 to 36 are shown in the drawing in such a way that their swivel axes 37 are aligned normal to the plane of representation of FIG. 1. In practice, the swivel axes of the joints 33 to 36 can be arranged in different spatial orientations relative to one another.

[0026] Starting from the initial section 21 up to the nozzle 23, the robot arm 22 is surrounded by a protective hose 40 which is designed to seal off the robot arm 22 from environmental influences such as may be present in the machining cell 8. By way of example, the protective hose 40 has two layers and comprises an inner hose 41 and an outer hose 42.

[0027] Associated with the initial section 21 of the robot 4 are a source of compressed air 24, a source of electrical power 25, and a fluid outlet 26 provided with a muffler. Furthermore, an electronic control 27 and a second valve module, the function of which will be described in more detail below, are accommodated in the initial section 21.

[0028] The machining head 5 is connected to the machine frame 3 via a multi-axis manipulator 50, which is configured to allow a milling tool 53 to move in three dimensions in order to allow the workpiece 2 to be machined as completely as possible. A supply of cooling lubricant from the machining head 5 to the milling tool 51 may be provided for carrying out a workpiece machining operation. In any case, the machining of the workpiece 2 results in a contamination of the workpiece 2 by chips which are to be removed before further transport of the workpiece 2 by means of the robot 4.

[0029] By way of example, it is provided that a conveyor, which is not shown, is integrated in the workpiece carrier plate 6, which is only shown schematically, and which conveyor is designed for a movement of the workpiece 2 between a workpiece holder 51 arranged below the machining head 5 and a workpiece changing station 52 arranged below the robot 4. The conveyor enables a rapid exchange of workpieces 2 between the workpiece changing station 52 and the workpiece holder 51, whereby a simultaneous machining of a workpiece 2 with the machining head 5 as well as a cleaning of a further workpiece 2 can preferably be carried out with the robot 4.

[0030] Purely by way of example, the machining cell 8 is divided by a workpiece lock 7 into a working area, in which the machining head 5 and the workpiece holder 51 are arranged, and into a changing area, in which the robot 4 and the workpiece changing station 52 are arranged. The workpiece lock 7 can be opened for the exchange of workpieces 2 and is closed during the machining of the workpiece 2 or the cleaning of the workpiece 2. In FIGS. 2 and 3, the joint 36 arranged between the third arm part 30 and the fourth arm part 31 is shown from two opposite spatial directions. The joint 36 is representative of the other joints 33 to 35, which are preferably of the same type, in particular identical, as the joint 36.

[0031] Purely exemplarily, the joint 36 which is arranged between the third arm part 30 and the fourth arm part 31 also includes the pneumatic drive 43, which is designed as a pneumatic swivel drive and which enables a limited swivel movement between the third arm part 30 and the fourth arm part 31 about the swivel axis 37 aligned normal to the plane of representation of FIGS. 2 and 3.

[0032] By way of example, the pneumatic actuator 43 comprises an annular actuator housing 44 extending along the pivot axis 37 and having an outer surface connected to the third arm portion 30.

[0033] As can be seen from the illustration of FIG. 3, a drive shaft 45 is rotatably mounted in the drive housing 44, which is connected to the fourth arm part 31 and which determines the pivot axis 37. Fixed to the drive shaft 45 is a sealing sleeve 47 which carries a working vane 46 extending outwardly in the radial direction. The working vane 46, together with the undesignated inner surface of the drive housing 44 and a sealing ridge 48 of the drive housing 44 projecting inwardly in the radial direction, defines a first working chamber 55 and a second working chamber 56. In this regard, the working vane 46 and the sealing sleeve 47 are pivotally sealingly received in the drive housing 44, thereby allowing the volume of the first working chamber 55 and the second working chamber 56 to be varied.

[0034] A fluid connection 57, 58 is associated with each of the working chambers 55, 56, via which a supply and discharge of compressed air into and out of the respective working chamber 55 resp. 56 from the respective working chamber 55 or 56 can be carried out. In the presence of a pressure difference between a first fluid pressure in the first working chamber 55 and a second fluid pressure in the second working chamber 56, there is a resulting force effect on the working vane 46, which leads to a torque on the drive shaft 45, whereby a pivoting movement of the fourth portion 31 relative to the third arm portion 30 can be caused.

[0035] A compressed air supply and a compressed air discharge for the first working chamber 55 are provided via a first fluid line 63 connected to the first fluid port 57 and connected to a first control valve 59 and a second control valve 60. In a purely exemplary manner, the first control valve 59 is provided as a venting valve and controls a fluid flow from the compressed air source 24 into the first working chamber 55. In an exemplary embodiment, the second control valve 60 is provided as a venting valve and allows venting of the first working chamber 55 via the fluid outlet 26. Similarly, the second working chamber 56 is connected via a second fluid line 64 to a third control valve 61 and a fourth control valve 62, by means of which it is also possible to pressurize or vent the second working chamber 56. The control valves 59 to 62 are fluidically connected to the compressed air source 24 and the fluid outlet 26, respectively, depending on their assigned task. The control valves 59 to 62 are fluidically connected to the compressed air source 24 or the fluid outlet 26, depending on their assigned task, and are electrically connected to a valve control 15 mounted directly on the third arm part 30, which is also referred to as the first valve module. Depending on the design of the control valves 59 to 62, which can be selected, for example, from the group: switching valves, proportional valves, the valve control 15 is set up to control the control valves 59 to 62 as required depending on control signals which are provided by the electronic control 27 via a control line 16. Furthermore, the valve control 15 is connected to the compressed air source 24 via a compressed air line 38 and to the fluid outlet 26 via an outlet line 39 and can thus influence compressed air flows to the pneumatic drive 43 or from the pneumatic drive 43.

[0036] Furthermore, according to the representation of FIG. 2, it is provided that a sensor system 17 is arranged in the drive housing 44, which comprises an encoding disk 18 connected to the drive shaft 45 in a rotationally fixed manner and a sensor 19, wherein the sensor 19 is electrically connected to the valve control 15 via a sensor line 20. By way of example, the coding disk 18 has an optically or magnetically scannable incremental or absolute coding arranged in an annular manner coaxially with the pivot axis 37, which is scanned by the sensor 19. The sensor 19 provides a sensor signal, dependent on the result of the scanning, to the valve control 15 via the sensor line 20. Depending on the design of the valve control 15 as well as the electronic control 27, it may be provided that a control of a swivel position is performed by the valve control 15. In this case, a swivel angle information for the fourth joint 36 is provided by the electronic control 27. Alternatively, it can be provided that the sensor signal of the sensor 19 is forwarded to the electronic control 27 without intermediate processing in the valve control 15, where a comparison is made between a stored setpoint value and an actual value for the pivoting position of the fourth joint 36. From any deviation between the setpoint value and the actual value, the electronic control 27 then determines suitable control signals which are transmitted to the valve control 15 and are converted there into corresponding valve control signals for the control valves 59 to 62.

[0037] A pneumatic supply to the nozzle 23, which is arranged at the end of the fourth arm part 31, is provided via a fluid supply line 65 which, starting from the second valve module 12, which is accommodated purely exemplarily in the initial section 21 and which is connected to the compressed air source 24, extends to the end of the fourth arm part 31 and is connected there to a fluid connection 66 of the nozzle 23.

[0038] Furthermore, a human machine interface 9 is associated with the fourth arm portion 31, which human machine interface is designed, for example, as an electrical push-button switch and which is connected to the electronic control 27 via an electrical line which is not shown. The human machine interface 9 makes it possible, for example, to store joint positions of the joints 33 to 36 which the robot arm 22 is to assume in order to carry out a cleaning operation for the workpiece 2. Purely by way of example, it can be provided that such a storage of joint positions is carried out by briefly actuating the human machine interface. Furthermore, it can be provided that a setting of a jet cross-section for the nozzle 23, which is designed to be adjustable in a manner not shown in more detail, may be set by a longer-lasting actuation of the human machine interface 9 in the respective cleaning position.

[0039] In an alternative embodiment of a nozzle 73, as shown in FIG. 4, this nozzle 73 is a system which comprises three differently designed compressed air nozzles 74, 75, 76 which are arranged on the fourth arm part 31 in a purely exemplary manner The compressed air nozzles 74, 75, 76 can be controlled by a valve arrangement arranged in the fourth arm part 31, not shown, which is electrically connected to the electronic control 27, in an alternative or parallel manner for providing compressed air.

[0040] Purely by way of example, each of the compressed air nozzles 74, 75, 76 is assigned a respective indicator lamp 77, 78, 79, by means of which it can be indicated which of the compressed air nozzles 74, 75, 76 is to be activated during the performance of the teach-in process. Switching between the compressed air nozzles 74, 75, 76 can be carried out, for example, with the aid of the human machine interface 9. Alternatively, it can be provided that a, in particular capacity based, scanning of the compressed air nozzles 74, 75, 76 is carried out by the electronic control 27 or the valve control 15 and user inputs are detected by this scanning process. By way of example, during the execution of the teach-in process, a user can, by touching the respective compressed air nozzle 74, 75, 76, select an activation position and/or an activation time for the use of the respective compressed air nozzle 74, 75, 76 during the subsequent execution of the cleaning process and receives a visual feedback about the respective activation carried out by the associated indicator lamp 77, 78, 79. In addition, it can be provided that, for example, the storage of a position of the robot 4 is triggered by a longer lasting contact with one of the compressed air nozzles 74, 75, 76.