WO2021058530A1

WO2021058530A1 - Device for supplying a wire-shaped material

Info

Publication number: WO2021058530A1
Application number: PCT/EP2020/076516
Authority: WO
Inventors: Frank Kubisch; Martin WOLLENHAUPT; Karsten KNECHTEL
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2019-09-26
Filing date: 2020-09-23
Publication date: 2021-04-01
Also published as: DE102019126022A1

Abstract

The invention relates to a device for supplying a wire-shaped material, wherein two identical wheels (1.1, 1.2) which can be driven about parallel rotational axes are arranged in a housing (5) such that the material (2) is in contact with the wheels between the lateral surfaces. The material (2) can be conveyed by a first wire guiding element (3.1) and by a second wire guiding element (3.2) arranged behind the wheels (1.1, 1.2) in a feed movement direction. The rotational axis of a first wheel (1.1) cannot be moved, and a second wheel (1.2) can be moved perpendicularly to the feed movement direction of the material (2). The housing (5) is equipped with a first fine drive (4) which acts perpendicularly to the feed movement direction of the wire-shaped material (2) against a rotatable lever arm (6), and a spring element (7) is arranged on the lever arm (6) opposite the force application point of the first fine drive (4), said spring element exerting a pressure against the lever arm (6).

Description

Device for feeding wire-like material

The invention relates to a device for supplying wire-shaped material with an outside diameter or a cross-sectional dimensioning equivalent thereto in the range 0.05 mm to 0.5 mm in a welding or soldering process. A dimensioning <0.4 mm is preferred.

A new high-precision fine wire feed system for pulsed laser welding, CW laser welding, soldering, build-up welding, electron beam welding and much more can be made available.

The wire-like material can be low-alloy and high-alloy steel alloys, suitable Al alloys, bronzes, noble metal alloys, Cu or gold wires. In addition to circular cross-sectional shapes, a wire-like material can have a polygonal cross-sectional geometry and can also be processed in this way with a device according to the invention. With these miniaturized cross-sectional areas of a wire-shaped material, a particularly careful and precise adjustment of the individual components is important in order to achieve a slip-free, trouble-free and precise supply of wire-shaped material to the desired location and in the desired amount at a time.

An automatic welding wire feed for slip-free conveyance of welding wires with an outer diameter of 0.3 mm to 1.2 mm is known from L&A GmbH. The wire feed system can be used both in the pulsed laser welding process and in CW mode. The wire feed is implemented by two driven, finely toothed hard metal wheels that rotate in opposite directions and between which the wire is fed. The invention is also based on this principle. This means that a high torque can preferably be achieved by means of a planetary gear for the feed and no slip because of the external toothing of the hard metal wheels. These have an outer diameter of the same size and are driven at the same angular or circumferential speed. A defined notch profile is formed on the surface of the wire by means of the toothing on the outer jacket surface.

With the adjustment frame, the wire axes of the "inner capillary tubes" of the drive are set individually to the diameter of the filler metal used.

As already stated, in the case of wire-shaped materials with smaller external dimensions, a high-precision adjustment is required in order to achieve a very precise and slip-free feed movement.

It is therefore the object of the invention to provide possibilities for a disruption-free, slip-free feed movement of a wire-shaped material for a joining process, in which, in particular, an energy beam in whose area of influence the wire-shaped material can be conveyed continuously or successively at a defined feed speed can be achieved to specify.

According to the invention, this object is achieved with a device which has the features of claim 1. Advantageous configurations and further Formations of the invention can be implemented with features identified in the subordinate claims.

According to the invention, two identical wheels, which are driven by at least one drive and are aligned parallel to one another, are arranged in a housing in such a way that wire-like material between the outer surfaces is in contact with them stands. With synchronous counter-rotating rotation of the wheels, wire-shaped material is conveyed in the direction of a workpiece by a first wire guide element arranged in front of the wheels and by a second wire guide element arranged behind the wheels in the direction of feed movement. The individual teeth of the toothing can advantageously be inclined at an angle other than 0 ° with respect to the axis of rotation of the wheels, preferably at an angle of approximately 15 °. The angles of inclination on the two wheels should be chosen to be opposite in each case in order to enable better guidance of the wire-like material during the advance movement.

The first and second wire guide elements each have a capillary-shaped wire guide whose outside diameter or a cross-sectional dimensioning equivalent thereto is minimally larger than the outside diameter or the equivalent cross-sectional dimensioning of the wire-shaped material. An equivalent cross-sectional dimensioning of a triangular cross-section corresponds to the longest outer edge and, in the case of a polygonal cross-section, for example, to a surface diagonal. With polygonal cross-sectional geometries, instead of wire-shaped materials, strip-shaped materials can also be conveyed with the device.

An outlet opening of the first wire guide element is in the direction of movement of the wire-like material in front of the wheels and an opening of the second wire guide element is arranged in the direction of feed movement of the wire-like material behind the wheels. A first wheel is attached to the housing in such a way that the axis of rotation cannot be displaced. The second wheel is perpendicular to the feed direction of movement of the wire-shaped material to adapt to the respective outer diameter or an equivalent cross-sectional dimension and to influence a notch depth on the outer surface of the wire-shaped material. For this purpose, a first fine drive is arranged on the housing, which acts perpendicular to the feed movement direction of the wire-shaped material against a lever arm. The lever arm is rotatably mounted in the housing with a swivel joint which is arranged at a distance from the force application point of the first fine drive.

The second wheel is rotatably attached to the lever arm with its axis of rotation between the force application point and the swivel joint. A pressure force exerting pressure force against the lever arm is arranged opposite the force application point of the first fine drive on the lever arm. With the acting compressive force of this spring element and the Wegbe limiting effect, which can be achieved with the first fine drive, the notch depth of the notches on the outer surface of the wire-shaped material, which with the teeth of the toothing, which is on the radially outer surface of the wheels are designed to be influenced, since the first fine drive with its force application point on the lever arm acts opposite the Federele element.

In this way, the distance between the outer profiled lateral surfaces of the two wheels can be set very precisely as a function of the respective cross-sectional dimensions of the wire-like material to be conveyed. As a result, the notch depth of notches, which are influenced in a defined manner on the surface of the respective wire-shaped material, by the toothing that is present on the radially outer circumferential surfaces of both wheels. This leads to the fact that a defined and slip-free conveyance of the wire-shaped material is achieved and its undesired damage or even tearing can be avoided.

It is also advantageous to minimize the distance between the two wire guide elements and the outer circumferential surfaces of the wheels in the XY direction. Ren dimensions of the wire guide elements on the end faces facing the wheels, which in turn are also dependent on the outer dimensions of the wire-like material to be conveyed.

For this purpose, a guide unit can be present on each of the two wire guide elements, each of which is designed so that the respective wire guide element can be moved parallel and perpendicular to the feed movement axis of the wire-like material so that the longitudinal axes of capillaries of the wire guide elements through which the wire-like material passes can be moved, are aligned with one another and the guide units can be fixed in a predeterminable position on the housing by means of at least one fixing element each.

An eccentric element can be arranged in a guide on each of the guide units, with which movement of the respective wire guide element paral lel to the feed movement direction of the wire-shaped material can be achieved by a defined rotation of the respective eccentric element, so that in each case a minimal distance between the outer contour of the outlet opening of the first wire guide element and the outer Mantelflä surfaces of the wheels and the outer contour of the inlet opening of the second wire guide element and the outer circumferential surfaces of the wheels can be reached in which no contact of the wire guide elements with the outer Man is telflächen the wheels.

In addition, a fine drive can act on the guide units, with which a movement of the wire guide elements perpendicular to the feed direction of movement of the wire-shaped material can be achieved. Opposite the respective fine drive, a spring element can act on the respective guide unit, which exerts a compressive force in the direction of wire-shaped material on the respective guide unit. As a result, the alignment of the central longitudinal axes of the capillaries of the wire guide elements can be achieved, so that tilting during the feed movement is avoided and a wire-like material is reliably threaded in after exiting the outlet opening of the first wire guide element for entry into the inlet opening of the second wire guide element in the case of a Change of a wire-like material can be secured. To maintain a minimum distance between wire guide elements and the outer surface of the wheels, the front sides of the wire guide elements pointing in the direction of the wheels can be designed in a conically tapered truncated cone or truncated pyramid shape. A minimum distance of 0.05 mm and possibly even smaller to the outer surface of the wheels can be maintained.

The fine drives can be operated electrically, for example as a linear motor with a gearbox or also as or with piezo actuators. However, micrometer screws with which a very precise setting of the adjustment can be achieved with high resolution and precision are advantageous.

To increase the setting accuracy of the distance between the outer circumferential surfaces of the two wheels, the force application point of the first fine drive on the lever arm, the arrangement of the pivot joint of the lever arm and the arrangement of the axis of rotation of the second wheel on the lever arm can be selected so that a reduction between the feed movement of the first fine drive and the movement of the second wheel perpendicular to the feed movement of the wire-shaped material, preferably from at least 2 to 1 can be achieved. For example, with a movement of a micrometer screw as a fine drive by 0.01 mm, a movement of the second wheel perpendicular to the feed movement direction of the wire-shaped material by 0.005 mm can be achieved.

The fixing elements can be designed as locking screws or tensioning screws which engage the respective guide unit and the housing or can be screwed into them.

The wire guide elements can be exchangeable, taking into account the respective outer diameter or an equivalent cross-sectional dimensioning of the wire-shaped material. After the exchange, a new alignment and adjustment can be carried out with the above-mentioned means.

To reduce the frictional forces acting during the feed movement of the wire-shaped material, the inner wall of the capillaries of the wire Guide elements be formed at least in some areas with PTFE or coated with it. For example, starting from the end faces facing away from the two wheels, hollow, channel-shaped elements made of PTFE can be inserted into the wire guide elements whose free cross-section is adapted to the geometry and dimensions of the respective wire-shaped material. Then only the areas of the inner capillary walls of the wire guide elements pointing directly in the direction of the two wheels are made of a different material, which can have a higher coefficient of friction than the PTFE.

Feed rates for the wire-like material between 0.1 mm / s and 150 mm / s can be achieved.

The wheels can be driven directly, but preferably via a common transmission. Their rotary movement takes place at the same circumferential speed. They preferably have the same outside diameter.

The invention can be used for a special functionalization of existing component surfaces or changes to the component shape. Example applications can be found in the following areas: laser welding in pulsed lasers and in the CW area, application of wear protection layers with Fe, Co, Cu, Au alloys, fine repairs of high-quality, wear-stressed functional components made of Ti and Ni aerospace alloys, in the additive manufacturing of thin-walled structures made of Al, Ni, and Ti alloys, in soldering applications of, for example, microprocessors, electron beam welding in the glass and wafer semiconductor industry, other high-precision wire feed applications for the manufacture of springs and in the Areas outside of thermal processing.

The invention is to be explained in more detail below by way of example.

Show:

Figure 1 shows an example of a device according to the invention and FIG. 2 shows a partial view of an example of a wire guide element which is arranged in relation to the two wheels used for the feed movement.

In the example shown in Figure 1, two wheels 1.1 and 1.2 for realizing the feed movement of the wire-shaped material 2 are rotatably mounted in a housing 5. The axes of rotation point perpendicularly into the plane of the drawing. They are driven by a drive motor, not shown, in this example via the two gears 15.1 and 15.2 at the same speed but in the opposite direction of rotation.

The wire-shaped material 2 is fed via a wire feed (not shown) through a tubular capillary 13.1, which is formed in the first wire guide element 3.1, from the outlet opening into the gap between the radially outer lateral surfaces of the wheels 1.1 and 1.2.

The wire-shaped material 2 occurs via an inlet opening of the tubular capillary 13.2, which is formed in the second wire guide element 3.2, and can be conveyed through this in the direction of a processing zone. The direction of feed movement is indicated by the arrow.

The first wheel 1.1 is firmly fixed in the housing 5 so that its rotational axis cannot be shifted. The second wheel 1.2 is attached to the lever arm 6, which is rotatably mounted on the housing 5 with the swivel joint (not visible) in the area of the second gear wheel 15.2. On the lever arm 6, the Federele element 7 engages and exerts a compressive force on the lever arm 6. On the opposite side of the lever arm 6, the force application point for the micrometer screw is arranged as a fine drive 4. By turning the micrometer screw, the lever arm 6 and thus also the second wheel 1.2 can be moved. The second wheel 1.2 can thereby be shifted perpendicular to the direction of movement (x-direction), whereby the gap between tween the radially outer circumferential surfaces of the wheels 1.1 and 1.2 is adjusted accordingly. The respective outer diameter and a ge desired notch depth of notches, which with the teeth, which are formed on the radially äu ßeren lateral surface of the wheels 1.1 and 1.2, on the outer Surface of the wire-shaped material 2 are formed, are influenced. With the lever ratios, a transmission ratio of the movement of the force application point and the movement of the axis of rotation of the second wheel 1.2, as has been explained in the general part of the description, can be realized.

The two wire guide elements 3.1 and 3.2 can be moved with the guide units 8.1 and 8.2 and the fine drives 9.1 and 9.2, which are also micrometer screws in the example, perpendicular to the direction of feed movement direction of the wire-like material 2, which in particular the aligned alignment of the capillaries 13.1 and 13.2, which are formed in the wire guide elements 3.1 and 3.2 and through which the wire-shaped material 2 is conveyed, can be achieved.

The guide units 8.1 and 8.2 are each engaged by a spring element 12.1 and 12.2, with which a compressive force can be exerted against the respective guide unit 8.1 or 8.2 in the direction of the fine drive 9.1 or 9.2 in order to achieve the desired positioning, alignment and adjustment of the capillaries 13.1 or 13.2 to enable, even if currently by means of the respective fine drive 9.1 or 9.2 there is no displacement movement of the respective first or second guide unit 8.1 or 8.2 in the direction perpendicular to the feed movement direction of the wire-shaped material 2 (X-direction).

For a movement of the guide units 8.1 and 8.2 with their respective wire guide elements 3.1 and 3.2 in the direction parallel to the feed movement direction (Y-direction), the guide units 8.1 and 8.2 each have a guide groove in each of which an eccentric element rotatable about an axis of rotation 10.1 and 10.2 has been introduced. By rotating one of the eccentric elements 10.1 or 10.2, the respective guide unit 8.1 or 8.2 and thus the corresponding first or second wire guide element 3.1 and 3.2 can be moved so that a minimum distance between the end faces of the wire guide elements 3.1 and 3.2, which in the direction of the Rä the 1.1 and 1.2 are arranged, and the radially outer circumferential surfaces of the first and the second wheel 1.1 and 1.2 can be maintained, what the threading of the wire-like material 2 into the inlet opening of the capillary, which is guided through the second wire guide element 3.2, makes it easier and safer.

The guide units 8.1 and 8.2 can be fixed to the housing 5 with two fixing elements 11.1 and 11.2 respectively after successful adjustment in relation to the outer jacket surfaces of the wheels 1.1 and 1.2. As Fixierele elements 11.1 or 11.2, the locking screws can be screwed into a hole in the housing 5.

The partial section shown in Figure 2 can be seen that a facing in the direction of the wheels 1.1 and 1.2 front end (outer contour) of both wire guide elements 3.1 and 3.2 can be designed conically ver younger in this direction. As a result, both wire guide elements 3.1 and 3.2 can be brought even closer without contact to the radially outer shell surfaces of the wheels 1.1 and 1.2 and thus the distance between the outlet opening for wire-like material 2 on the first wire guide element 3.1 and the inlet opening on the second wire guide element 3.2 (in FIG 2 not shown) to a minimum.

In addition, FIG. 2 shows a possible design of a capillary 13.1 or 13.2, which is then conveyed again through the respective wire guide element 3.1 or 3.2 and then again wire-shaped material 2 through the capillary 13.1 and 13.2. At a distance from the inlet and outlet opening for wire-shaped material 2, the inner diameter of circular or polygonal wire-shaped material 2 or the free cross-sectional area of the respective capillary 13.1 or 13.2 is enlarged. In this area of the capillaries 13.1 and 13.2, an inner coating made of PTFE or an internally hollow element 14 made of PTFE can be present. The wire-shaped material 2 can then be conveyed through the respective capillary 13.1 or 13.2 with reduced friction through a hollow element 14.

Claims

1. Device for feeding wire-like material with a

Outer diameter or an equivalent cross-sectional dimensioning in the range 0.05 mm to 0.5 mm in a welding or soldering process, with two identical wheels (1.1, 1.1, 1.2), which are each seen with a toothing on their radially outer shell surfaces aligned parallel to one another, are arranged so that wire-shaped material (2) between tween the shell surfaces is in contact with them and with synchronous counter-rotation of the wheels (1.1, 1.2 ) by a first wire guide element (3.1) arranged in the feed movement direction in front of the wheels (1.1, 1.2) and by a second wire guide element (3.2) arranged in the feed movement direction behind the wheels (1.1, 1.2) in the direction of a workpiece and thereby first and second Wire guide element (3.1, 3.2) each have a capillary wire guide, the outer diameter of which it or an equivalent cross-sectional dimensioning is minimally larger than the outer diameter of the wire-shaped material (2) and an outlet opening of the first wire guide element (3.1) in the feed direction of movement of the wire-shaped material (2) in front of the wheels (1.1, 1.2) and an inlet opening of the second wire guide elements (3.2) is arranged behind the wheels (1.1, 1.2) in the feed movement direction of the wire-like material (2) and a first wheel (1.1) is attached to the housing (5) in such a way that the axis of rotation cannot be displaced and a second wheel ( 1.2) perpendicular to the feed movement direction of the wire-shaped material (2) for adaptation to the respective external diameter or an equivalent cross-sectional dimensioning and to influence a notch depth on the outer jacket surface of the wire-shaped material (2) is displaceable, with a first fine drive (4) being arranged on the housing, which is perpendicular to the feed movement direction of the wire-shaped material (2) A lever arm (6) acts, which is rotatably mounted with a swivel joint, which is arranged at a distance from the force application point of the first fine drive (4), and the second wheel (1.2) with its axis of rotation on the lever between the force application point and the swivel joint arm (6) is rotatably attached and the force application point of the first fine drive (4) on the lever arm (6) opposite a against the He belarm (6) acting pressure force exerting spring element (7) is arranged.

2. Device according to claim 1, characterized in that each of the two wire guide elements (3.1, 3.2) has a respective guide unit (8.1, 8.2) which is designed so that the respective wire guide element (3.1, 3.2) is parallel and perpendicular to the feed movement axis of the wire-like material (2) is movable so that the longitudinal axes of capillaries (13.1, 13.2) of the wire guide elements (3.1, 3.2), through which the wire-like material (2) are moved, are aligned and the guide units (8.1 , 8.2) can be fixed in a predeterminable position by means of at least one fixing element (11.1, 11.2) on the Ge housing (5).

3. Device according to the preceding claim, characterized in that the guide units (8.1, 8.2) each have a Feinan drive (9.1 and 9.2) engages, with which a movement perpendicular to the advance direction of movement of the wire-like material (2) can be achieved, and the respective fine drive (9.1, 9.2) opposite a spring element (12.1, 12.2) engages the respective guide unit (8.1, 8.2), which exerts a compressive force in the direction of wire-shaped material (2) on the respective guide unit (8.1, 8.2).

4. Device according to one of the preceding claims, characterized in that on the guide units (8.1, 8.2) each in one Guide an eccentric element (10.1, 10.2) is arranged, with which by a defined rotation of the respective eccentric element (10.1,

10.2) a movement of the respective wire guide element (3.1, 3.2) parallel to the feed direction of movement of the wire-shaped material (2) can be achieved, so that in each case a minimum distance between the outer contour of the outlet opening of the first wire guide element (3.1) and the outer circumferential surfaces of the wheels (1.1 and 1.2) and the outer contour of the inlet opening of the second wire guide element (3.2) and the outer circumferential surfaces of the wheels (1.1 and 1.2) can be reached, in which no contact of the wire guide elements (3.1 and 3.2) with the outer circumferential surfaces of the wheels ( 1.1 and 1.2).

5. Device according to one of the preceding claims, characterized in that the end faces of the wire guide elements (3.1, 3.2) pointing in the direction of the wheels (1.1, 1.2) pointing end regions are conically tapered in the shape of a truncated cone or a truncated pyramid.

6. Device according to one of the preceding claims, characterized in that the first, second and / or third fine drive (4, 9.1,

9.2) are designed as a micrometer screw.

7. Device according to one of the preceding claims, characterized in that the force application point of the first fine drive (4) on the lever arm (6), the arrangement of the rotary joint of the lever arm (6) and the arrangement of the axis of rotation of the second wheel (1.2) on the lever arm (6) are chosen so that a reduction between the feed movement of the first fine drive (4) and the movement of the second wheel (1.2) perpendicular to the feed movement of the wire-shaped material (2), preferably of at least 2 to 1, can be achieved.

8. Device according to one of the preceding claims, characterized in that the fixing elements (11.1, 11.2) ben as locking screws or clamping screws that are attached to the respective guide unit (8.1,

8.2) attack or can be screwed into it, are formed. 9. Device according to one of the preceding claims, characterized in that the wire guide elements (3.1 and 3.2), taking into account the respective outer diameter or an equivalent cross-sectional dimensioning of the wire-like material (2), are interchangeable.

10. Device according to one of the preceding claims, characterized in that the inner wall of the capillaries (13.1, 13.2) of the wire guide elements (3.1, 3.2) is at least partially formed with PTFE (14) or coated with it.