INSTALLATION AND METHOD FOR THE METALLIC COATING OF A WORKPIECE

Abstract

The invention relates to an installation and a method for the metallic coating of a workpiece using a coating device, said coating device comprising a displaceable coating lance, by which a metal plasma jet can be generated to create a coating of metal particles. According to the invention, it is provided that the coating device with the coating lance and a measuring device for measuring the coating thickness are jointly integrated in the installation, and that the coating device with the coating lance as well as the measuring device are enclosed by a housing.

Claims

1. Installation for the metallic coating of a workpiece (1), with a housing (13), in which a loading station (12) for the supply and discharge of the workpiece (1) (1) and a processing station (14) with a coating device (29) are provided, whereby the coating device comprises a displaceable coating lance (30), by which a metal plasma jet can be generated to create a coating of metal particles, whereby the coating device (29) with the coating lance (30) and a measuring device (52) for measuring the coating thickness are jointly integrated in the installation (10) and arranged in the housing (13), characterized in that the processing station (14) and the loading station (12) are separated from one another by means of a partition wall (24), the partition wall (24) comprises at least one closable passage (25), the measuring device (52) is arranged in the loading station (12), and that the measuring device (52) is designed to measure the workpiece (1) before and after the coating.

2. Installation according to claim 1, characterized in that the measuring device (52) comprises a displaceable measuring sensor (53), which is displaceable between a calibration station (56) and a workpiece holder (23) in the loading station (12).

3. Installation according to one of the claim 1 or 2, characterized in that a cleaning station (60) for cleaning the coating lance (30) is arranged in the processing station (14).

4. Installation according to claim 3, characterized in that in the processing station (14) a testing station (54) for testing the metal plasma jet generated by the coating lance (30) is arranged.

5. Installation according to one of the claims 1 to 4, characterized in that a suction device is provided, which is designed to extract air from the coating device (29), the calibration station (56), the testing station, and/or the cleaning station (60).

6. Installation according to one of the claims 1 to 5, characterized in that at least one workpiece holder (23) is provided, in which a workpiece (1) can be deposited and clamped in a defined position, and that the workpiece holder (23) is displaceable between the loading station (12) and the processing station (14).

7. Method according to one of the claims 1 to 6, characterized in that passage (25) is closed by a locking element (27), which releases the passage (25) in order to allow the through-passage of the workpiece (1).

8. Installation according to one of the claim 6 or 7, characterized in that the at least one workpiece holder (23) is displaceable by means of a conveyor (20), which has an annular circulation path.

9. Installation according to claim 8, characterized in that the conveyor (20) is shaped as a rotary table (22) that is arranged horizontally displaceable.

10. Installation according to one of the claims 1 to 9, characterized in that in the partition wall (24) two passages (25) are provided with one locking element (27) each.

11. Installation according to one of the claims 8 to 10, characterized in that the conveyor (20) is arranged circumferentially in horizontal direction, and that the workpiece holder (23) is adjustably mounted to the conveyor (20), in particular pivotably around a horizontal pivoting axis.

12. Method for the metallic coating of a workpiece (1) with a displaceable coating lance (30), by which a metal plasma jet can be generated, by means of which a metallic coating of metal particles on the workpiece (1) is created, characterized in that the creation of the coating and a measuring of the coating thickness are carried out integrated in an installation (10), which is designed in accordance with any one of the claims 1 to 11, whereby a loading station (12) for supplying and discharging the workpiece (1) is provided, with which the workpiece (1) is measured before and after coating.

Description

[0028] The invention is described hereunder with reference to a preferred embodiment example that is schematically illustrated in the attached drawings. The illustrations show the following:

[0029] FIG. 1: a schematic lateral view of an installation according to the invention;

[0030] FIG. 2: a side view of the installation of FIG. 1 folded by 90° in a strongly schematic form;

[0031] FIG. 3: a top view of the installation according to FIGS. 1 and 2;

[0032] FIG. 4: a schematic perspective view of the installation according to FIGS. 1 and 3, however without housing.

[0033] An installation 10 according to the invention for the metallic coating of bores 3 in a workpiece 1 is shown in FIGS. 1 to 4. The workpiece 1 in the illustrated embodiment example is an engine mount with 12 bores 3, which are arranged as cylinder bores in two rows of six in a V configuration in workpiece 1.

[0034] The installation 10 comprises a machine bed 11, on which a housing 13 is arranged. The box-shaped housing 13 encompasses a loading station 12 and a processing station 14 with a coating device 29.

[0035] On the machine bed 11 a basic frame 16 of a conveyor 20 is arranged for taking up a workpiece 1, said conveyor being designed as rotary table 22 in the visualized embodiment example. The horizontal rotary table 22 driven rotatably around a vertical rotation axis comprises two workpiece holders 23 opposite one another, each of which can take up a plate-shaped pallet module 21 with one workpiece 1 each. The pallet module 21 with the workpiece 1 can be pivoted opposite the horizontal extension through a pivoting unit 26, so that the bores 3 in the workpiece 1 can be arranged vertically for carrying out the metallic coating.

[0036] The workpiece 1 is accepted at the loading station 12 by a feeding unit that is not shown in the illustration. In the area of the loading station 12 the housing 13 comprises an opening with a door not shown in the illustration. In addition, in the area of the loading station 12 a measuring of the workpiece 1 can be carried out with a measuring device 52. Subsequently, the rotary table 22 is rotated by an angle of 180°, whereby the workpiece 1 is transported from the loading station 12 to the opposite processing station 14. The processing station 14 is separated from the loading station 12 by means of a partition wall 24. The partition wall 24 is shown only partially in the lower part of FIG. 2. The partition wall 24, however, extends throughout the inside of the housing 13, so that the processing station 14 is separated from the loading station 12. For the passing through of the workpieces 1 from the loading station 12 to the processing station 14 and back two passages 25 are provided. The passages 25 are each closed by means of a displaceable locking element 27, which is opened to allow the passing of the workpiece 1 and can subsequently be closed again.

[0037] The workpiece 1 is pivoted around a horizontal pivoting axis with the pivoting device 26 in the processing station 14, whereby one row of bores 3 is aligned vertically, as is apparent from FIGS. 1 to 4.

[0038] A coating device 29 is provided with a rod formed coating lance 30 for applying the metallic coating, which has at least one discharge opening 32 at its lower end for a metal plasma jet. The metal plasma jet is generated in a known way by means of a plasma generator comprising a cathode and a metallic anode. An electric arc is formed between the cathode and the anode by means of a correspondingly high electric voltage, by means of which the metallic anode is fused. The metallic anode is formed as feedable wire, so that there is always sufficient material to generate a metal plasma jet with the fused metallic particles. Instead of a wire, the supply of powder can also be provided as source of the metallic particles. A gas flow is generated by means of a gas jet installation, which is discharged through the discharge opening 32 at the lower end of the coating lance 30 almost horizontally at supersonic speed. The coating lance 30 with the discharge opening 32 is thereby introduced in the bore 3 to be coated in workpiece 1. The coating device 29 moreover comprises a tubular suction bell, which encases the coating lance 30, but which is not shown in FIGS. 1 to 4 for the sake of clarity.

[0039] For traversing the coating lance 30 a portal installation 40 with two parallel first traversing axes 41 is provided. On the first two traversing axes 41 a frame-like first displaceable slide 47 is arranged horizontally displaceable. The first displaceable slide 47 itself comprises two linear, horizontal second traversing axes 42, which extend parallel two one another and vertically to the first traversing axes 41.

[0040] Alongside the first two traversing axes 42 a beam-shaped second displaceable slide 48 is arranged horizontally displaceable. The second displaceable slide 48 itself has one single vertical third traversing axis 43. Alongside this third traversing axis 43, a sliding carriage 45 is positioned vertically displaceable. The coating lance 30 is rotatably held on the sliding carriage 45.

[0041] After positioning a workpiece 1 in the processing station 14, the coating lance 30 of the coating device 29 is fit in a first bore 3 of the workpiece 1 to be coated. The continuously operated coating lance 30 thereby generates a metal plasma jet which strikes one bore wall of the bore 3 at supersonic speed. By rotating the coating lance 30 and moving it axially in vertical direction, a regular pre-defined metallic coating with a thickness of, for instance, 10 μm to 300 μm is applied on the bore wall.

[0042] After retracting the coating lance 30 from the first coated bore 3, the metal plasma jet is directed towards an impact surface of a mounting unit in a suction bell not shown in the illustration directly after exiting the bore 3, whereby the suction bell is mounted on the sliding carriage 45 together with the coating lance 30. The mounting unit takes up the particles of the metal plasma jet and together with the coating lance 30 it is moved to the next bore 3 to be coated. Thereafter, the metallic coating is repeated at this second bore 3, whereby a corresponding coating of the further bore 3 in a row of the workpiece 1 follows. The workpiece 1 can subsequently be pivoted around a horizontal axis through the pivoting unit 26, so that the second row of the engine mount is arranged for processing in its vertical position. These six bores 3 in the engine mount-like workpiece 1 can be coated thereafter.

[0043] After completing the coating, the coating lance 30 with the portal unit 40 is retracted and the finished coated workpiece 1 can be transported back through the passage 25 on the right hand side, while simultaneously supplying a new workpiece 1 to be processed in the loading station 12. In that, the locking element 27 is opened at the passage 25. At the same time, a new workpiece 1 is transported from the loading station 12 to the processing station 14 through the opened passage 25 on the left hand side by means of the rotating movement of the rotary table 22.

[0044] The layer thickness and contour of the applied coating can be measured by a handling robot 50 comprising a measuring device 52. With the measuring device 52 the still uncoated bores 3 of a newly supplied workpiece 1 can be measured in advance, so that an even more accurate measuring of the completed coating by way of comparison of the measured data is made possible. The coated workpiece 1 can be removed from the workpiece holder 23 of the rotary table 22 in the loading station 12. Thereafter, a new workpiece 1 can be deposited in the workpiece holder 23 of the conveyor 20. Consequently, the loading and discharging as well as a measuring parallel to the processing of a workpiece 1 in the processing station 14 and thus without interfering with the machine's main time can take place in an installation 10 according to the invention. This makes an efficient use of the machine possible.

[0045] With the portal unit 40 the coating lance 30 can be moved to a testing station 54 at specific time intervals in order to verify the spray pattern of the metal plasma jet, or to a cleaning station 60.

[0046] The measuring device 52 comprises a laser with which the contour and the diameter of the bore 3 can be measured along the axial length of the bore 43 in that the measuring device 52 is vertically introduced into a bore 3 of the workpiece 1 through the handling robot 50. By comparing the measured data of bore 3 before and after coating, a control of the installation 10 helps determining the finished coating precisely with respect to the structure of the layer thicknesses and the surface contours. By comparing the measured values with the predefined target values it can be decided through controlling the installation 10, whether a correct coating has taken place, or whether the workpiece 1 has to be reworked. In addition, the control can adjust and modify set parameters of the coating device 29 based on the measured values, particularly the parameters for adjusting the metal plasma jet or the motion data of the coating lance 30 in order to counteract any aberrations in coating the following workpieces 1 in due course.