Metal layer deposition

Abstract

According to an example embodiment, an apparatus (100) for depositing a coating layer (123) of a second metal on a surface of an object (150) comprising a first metal is provided, the apparatus (100) comprising: a deposition assembly (120) comprising a wire feeder assembly (121) arranged to supply metal wire (122) comprising the second metal to a target position on a target plane of the deposition assembly (120), and a laser assembly (125) arranged to emit a laser beam (126, 127, 128) towards the target position so as to melt a portion of the metal wire (122) supplied thereto due to heat generated by the laser beam (126, 127, 128); a positioning assembly (130) for moving at least one of the object (150) and the deposition assembly (120) in order to move the target position in relation to said surface of the object (150); and a controller (140) arranged to control the positioning assembly (130) such that the target position is moved along said surface in order to deposit the coating layer (123) on said surface, wherein the laser assembly (125) comprises a beam shaping portion (125a) arranged to shape a light beam originating from a laser source into the laser beam (126, 127, 128) whose cross-section with the target plane encompasses the target position.

Description

[0001] Metal layer deposition

[0002] TECHNICAL FIELD

[0003] The present invention relates to deposition of a metal layer on a surface of an object made of another metal.

[0004] BACKGROUND

[0005] Coating of a metallic object with a layer of a metal of different kind finds many applications in various fields of technology. Typically, such a metallic coating is applied to provide the object with desired surface characteristics, which may relate to, for example, durability of the surface, friction of the surface, electrical conductivity of the surface, magnetic properties of the surface, etc.

[0006] In one class of examples, an object made of durable metal may be coated by a softer metal that has a relatively low melting point. In such examples the covering metal layer serves as a protection layer in applications where the surface of the object moves against a second surface: in case the friction between the surfaces moving with respect to each other unexpectedly increases, the additional heat first melts the coating layer before causing substantial damage to the first and second surfaces.

[0007] A particular example in this regard concerns plain bearings, where a shaft rotates against an inner surface of the bearing. Typically, a plain bearing is provided with a lubrication system to facilitate smooth rotation of the shaft within the bearing, where the lubrication is typically provided via a lubricant such as oil or grease applied between the inner surface of the bearing and the shaft. Large plain bearings, such as ones employed in powertrains of marine vessels, are subjected to high radial loads and therefore a failure in lubrication in the course of operation of the bearing typically results in serious damage both in the inner surface of the bearing and the shaft. In such a plain bearing, the inner surface of the bearing may be provided with a coating layer of the kind discussed above, i.e. one that is made of a material whose melting point is lower than the melting point of the material of a core of the bearing and the melting point of the material of the shaft. In such an arrangement possible loss of lubrication first results in melting of the coating layer on the inner surface of the bearing, which in many scenarios allows detection of such malfunction before any substantial damage occurs to the core of the bearing or to the shaft.

[0008] An example of such coating material is white metal known in the art, which is typically a tin-based or a lead-based alloy. A particular example of a white metal involves an alloy of tin, antimony and copper, which may further include small amounts of zinc, aluminum, arsenic, bismuth and / or iron. While relatively large plain bearings constitute a typical example concerning usage of the white metal as a protective coating layer, the white metal is applicable to serve as a coating material in many other applications as well.

[0009] White metal coatings are typically prepared via usage of various casting techniques. While such techniques have been optimized over time to provide white meatal coating layers that are applicable also in demanding operating conditions, these techniques nevertheless involve challenges e.g. in providing a desired layer thickness and / or in providing substantially uniform layer thickness throughout the surface area to be coated. Therefore, an improved technique for preparing a white metal coating would be highly desirable.

[0010] SUMMARY

[0011] In view of the foregoing, it is an object of the present invention to provide an improved manner of creating a metallic coating layer on a surface of a metallic object made of a metal of other kind.

[0012] The object(s) of the invention are reached by an apparatus and by a method as defined by the respective independent claims.

[0013] According to an example embodiment, an apparatus for depositing a coating layer of a second metal on a surface of an object comprising a first metal is provided, the apparatus comprising: a deposition assembly comprising a wire feeder assembly arranged to supply metal wire comprising the second metal to a target position on a target plane of the deposition assembly, and a laser assembly arranged to emit a laser beam towards the target position so as to melt a portion of the metal wire supplied thereto due to heat generated by the laser beam; a positioning assembly for moving at least one of the object and the deposition assembly in order to move the target position in relation to said surface of the object; and a controller arranged to control the positioning assembly such that the target position is moved along said surface in order to deposit the coating layer on said surface, wherein the laser assembly comprises a beam shaping portion arranged to shape a light beam originating from a laser source into the laser beam whose cross-section with the target plane encompasses the target position.

[0014] According to another example embodiment, an arrangement for depositing a coating layer of a second metal on a surface of an object comprising a first metal is provided is disclosed, the arrangement comprising an apparatus according to the example embodiment described in the foregoing and the object.

[0015] According to another example embodiment, a method for depositing a coating layer of a second metal on a surface of an object comprising a first metal is provided, the method comprising: supplying, from a deposition assembly, a metal wire comprising the second metal to a target position of a target plane of a deposition assembly; emitting, from the deposition assembly, a laser beam from the deposition assembly towards the target position so as to melt a portion of the metal wire supplied thereto due to heat generated by the laser beam, said emitting comprising shaping a light beam originating from a laser source into the laser beam whose cross-section with the target plane encompasses the target position; and moving at least one of the object and the deposition assembly to move the target position along a surface of said object in order to deposit the coating layer on said surface

[0016] The exemplifying embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the appended claims. As an example in this regard, the verb “to comprise” and its derivatives are used in the present disclosure as an open limitation that does not exclude the existence of also unrecited features. Moreover, unless explicitly stated otherwise, the features described in the following are combinable to other features even if not explicitly described in combination.

[0017] Some features of the invention are set forth in the appended claims. Aspects of the invention, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of some example embodiments when read in connection with the accompanying drawings.

[0018] BRIEF DESCRIPTION OF FIGURES

[0019] The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, where

[0020] Figure 1 depicts a block diagram that illustrates some aspects of a deposition apparatus according to an example,

[0021] Figure 2 schematically illustrates some aspects of a deposition assembly according to an example;

[0022] Figure 3 schematically illustrates some aspects of a deposition assembly according to an example;

[0023] Figure 4 schematically illustrates some aspects of a deposition assembly according to an example;

[0024] Figure 5 schematically illustrates some aspects of a deposition assembly according to an example;

[0025] Figure 6 illustrates a method according to an example; and

[0026] Figure 7 illustrates a block diagram of some elements of an apparatus according to an example.

[0027] DESCRIPTION OF SOME EMBODIMENTS Figures 1 and 2 illustrate some aspects of a deposition apparatus 100 according to an example. In this regard, Figure 1 depicts a block diagram that illustrates some elements of the deposition apparatus 100, whereas Figure 2 schematically depicts some aspects of structure and operation of the deposition apparatus 100. The deposition apparatus 100 is applicable for depositing a layer of a second metal on a surface of an object 150 comprising a first metal. In this regard, the second metal may have a melting point lower than that of the first metal. This aspect is discussed in further detail in the following. As illustrated in Figure 1 , the apparatus 100 comprises a deposition assembly 120 for depositing the second metal on the surface of the object 150, a positioning assembly 130 for moving the object 150 and / or the deposition assembly 120 and a controller 140 for controlling at least some aspects of operation of the positioning assembly 130 and the deposition assembly 120. In the following, the deposition apparatus 100 is referred to, in short, as an apparatus 100. Figure 1 further shows an optional holding assembly 110, which may be included in the apparatus 100 in some embodiments for holding the object 150.

[0028] As a general high-level overview of operation of the apparatus 100, the object 150 may be temporarily mounted to the holding assembly 110 (if applicable), whereas the controller 140 operates the positioning assembly 130 such that the deposition assembly 120 is moved along the surface of the object 150 and further operates the deposition assembly 120 to deposit the second metal on the surface in the course of this movement, thereby depositing a coating layer made of the second metal on the surface of the object 150. The structure and operation of the apparatus 100 is described in the following via a number of nonlimiting examples.

[0029] In this regard, the holding assembly 110 optionally included in the apparatus 100 may allow for temporarily mounting the object 150 thereto. In this regard, the term holding assembly 110 is to be construed broadly: in some embodiments, the holding assembly 110 may serve to support or hold the object 150 during operation of the apparatus 100 while the movement of the deposition assembly 120 in relation to the surface object 150 may be provided solely based on movement of the deposition assembly 120, whereas in some embodiments the holding assembly 110 may allow movement of the surface of the object 150 with respect to the deposition assembly 120 and the movement of the deposition assembly 120 in relation to the surface object 150 may be provided based on movement of the holding assembly 150 only or based movement of the holding assembly 110 and the deposition assembly 120. The examples described in the following assume presence of the optional holding assembly 110, whereas the examples described in the following readily generalize into ones where the holding assembly 110 is not applied but the object 150 may remain stationary on a support structure of suitable kind (such as a floor or a table) during operation of the apparatus 100 to deposit the coating layer on its surface.

[0030] Figure 2 provides a schematic illustration of some aspects of a structure and operating principle of the deposition assembly 120. The deposition assembly 120 comprises a wire feeder assembly 121 and a laser assembly 125. The wire feeder assembly 121 is arranged to supply a metal wire 122 comprising the second metal to a target position on a target plane, whereas the laser assembly 125 is arranged to emit a laser beam 126 power towards the target position in order to melt a portion of the metal wire 122 supplied onto the target position due to heat generated by the laser beam 126, thereby depositing the molten portion the second metal at a position of the surface of the object 150 brought to the target position. Moreover, the laser beam 126 also serves to pre-heat the surface of the object 150 around the target position (when brought to the target plane) before moving the target position thereon, which facilitates creating a strong bond between the surface and the second metal deposited thereon. In the schematic illustration of Figure 2, the horizontal dashed line indicates the target plane and the dashed circle indicates the target position on the target plane. The target plane and the target position thereon are defined in relation to the deposition assembly 120 and, consequently, any movement of the deposition assembly 120 also moves the target plane and the target position thereon accordingly. Figure 3 schematically illustrates the deposition assembly 120 shown in the illustration of Figure 2 together with the object 150. When the target position (indicated by the dashed circle) is brought onto a given position on the surface of the object 150, the heat arising from the laser beam 126 also heats the respective position on the surface of the object 150, which facilitates the molten portion of the metal wire 122 attaching on the respective position of the surface. Moreover, when the target position moves away from the respective position on the surface, the molten portion of the metal wire 122 cools down and solidifies thereon, thereby forming a respective portion of a coating layer 123 formed on the surface of the object 150 via operation of the apparatus 100, whereas the coating layer 123 may be created via moving the target position over a plurality of positions on the surface of the object 150 to cover an area of the surface to be provided with the coating layer 123.

[0031] The 7ositionning assembly 130 operates under control of controller 140 and it is arranged to move at least one of the object 150 and the deposition assembly 120 in order to move the target position of the deposition assembly 120 in relation to the surface of the object 150. Hence, the controller 140 may operate the positioning assembly 130 such that the target position is moved along the surface of the object 150 while operating the deposition assembly 120 to deposit the second metal. The movement of the target position may be provided along a movement path defined such that it covers the surface area of the object 150 to be provided with the coating layer 123.

[0032] In various examples, the movement of the target position of the deposition assembly 120 in relation to the surface of the object 150 may be provided via respective movement of the object 150 and / or the deposition assembly 120 e.g. in one of the following ways:

[0033] - The object 150 may be temporarily mounted to the holding assembly 110 that is moveable with respect to the deposition assembly 110, whereas the controller 140 is arranged to control the positioning assembly 130 to move the holding assembly 110 in order to move the target position in relation to the surface of the object 150. - The deposition assembly 120 is moveable with respect to the object 150, whereas the controller 140 is arranged to control the positioning assembly 130 to move the deposition assembly 120 in order to move the target position in relation to the surface of the object 150.

[0034] - The object 150 may be temporarily mounted to the holding assembly 110 that is moveable with respect to the deposition assembly 110 and the deposition assembly 120 is moveable with respect to the object 150, whereas the controller 140 is arranged to control the positioning assembly 130 to move both the holding assembly 110 and the deposition assembly 120 in order to move the target position in relation to the surface of the object 150.

[0035] The controller 140 may be arranged to operate the positioning assembly 130 to move the target position along the surface of the object at a predefined or selectable movement speed. The movement speed of the target point in relation to the surface of the object 150 may be user-definable movement speed or a predefined movement speed that is chosen, for example, from a range from 2 to 4 meters per minute. While this exemplifying range of movement speeds is applicable for various configurations of the apparatus 100, selection of the movement speed applied for a particular embodiment of the apparatus 100 and / or for providing a coating layer 123 of desired characteristics may be made, for example, in dependence of the applied laser power, a wire supply speed of the wire feeder assembly 121 and / or characteristics of the metal wire 122 (e.g. the thickness of the metal wire 122 and / or a melting point of the second metal).

[0036] The controller 140 may receive information that either directly or indirectly defines a movement path along the surface of the object via a user interface (U I) of the apparatus 100. Conversely, a user of the apparatus 100 may operate the III to enter the information that either directly or indirectly defines the movement path. In this regard, the III may comprise one or more user input components known in the art (such as a keyboard, a mouse, a touchscreen, a touchpad, etc.) that enable inputting information that serves to define the movement pattern. As non-limiting examples, information that directly defines the movement path may indicate a plurality of positions on the surface of the object 150, whereas information that indirectly defines the movement path may define an area on the surface of the object 150. In the latter example, the controller 150 may determine the movement path based on the area indicated in the information received via the III. In case the movement speed is user-definable, the controller 130 may receive the movement speed to be applied via the III. Additionally or alternatively, the controller 140 may be provided with a communication interface for communicating over a communication network and the controller 140 may receive information that defines the movement path and / or a selection of the movement speed via the communication interface from another apparatus coupled to the communication network.

[0037] The wire feeder assembly 121 may comprise a wire feeder known in the art and it may be arranged to supply the wire 122 made of the second metal to the target point at a predefined or at a user-definable (e.g. user-selectable) wire supply speed. The controller 140 may be arranged to control at least some aspects of operation of the wire feeder assembly 121 , e.g. one or more of the following: activation of the wire feed, deactivation of the wire feed, the wire supply speed. In case the wire supply speed is selectable, the controller 140 may receive the wire supply speed to be applied via the III (from the user) or via the communication interface (from another apparatus).

[0038] The wire supply speed may be chosen, for example, in a range from 1 to 4 meters per minute. While this exemplifying range of wire supply speeds is applicable for various configurations of the apparatus 100, selection of the wire supply speed applied for a particular embodiment of the apparatus 100 and / or for providing a coating layer 123 of desired characteristics may be made, for example, in dependence of the applied laser power, the movement speed of the target point in relation to the surface of the object 150 and / or characteristics of the metal wire 122 (e.g. the thickness of the metal wire 122 and / or a melting point of the second metal).

[0039] The thickness (e.g. the diameter) of the wire supplied from the wire feeder assembly 121 may be chosen in accordance with a particular embodiment of the apparatus 100 and / or in view of desired characteristics of the coating layer 123, for example, from a range from 1.5 to 3 millimeters. Selection of the metal wire thickness may be made, for example, in dependence of the applied laser power, the movement speed of the target point in relation to the surface of the object 150 and / or the melting point of the second metal.

[0040] The choice of the second metal applied for providing the layer 123 on the surface of the object 150 made of the first metal depends on the purpose of the coating layer 123 to be created. As described in the foregoing, the second metal preferably has a melting point lower than that the of the first metal, which results in providing the coating layer 123 as one that that protects the surface of the object 150 from damage in a scenario where the coated surface of the object 150 is subjected to excessive heat e.g. due to increased friction: in case the temperature of the coating layer 123 rises to its melting point, the coating layer 123 starts to melt while the surface of the object 150 under the coating layer 123 still remains unaffected by the increased temperature, which typically allows for reacting to the increased temperature before any substantial damage occurs to the surface of the object 150. In a particular example, the coating layer 123 serves to protect an inner surface of a plain bearing and / or an exterior of a shaft rotating within the plain bearing, whereas the increase in the temperature of the coating layer 123 may arise due to loss of lubrication between the inner surface of the plain bearing and the shaft.

[0041] A particular example of the second metal involves the white metal referred to in the foregoing. Along the lines described above, white metals are alloys known in the art and the white metal may be provided, for example, as a tin-based or as a lead-based alloy. In addition to their relatively low melting point, white metals also have a relatively low friction coefficient, which makes them especially well-suited for use as the material of the protective coating layer 123 of the kind described above for application e.g. on an inner surface of the plain bearing and / or on an exterior of the shaft rotating within the plain bearing. While any white metal known in the art may be applied by the apparatus 100, according to an example, the white metal applied by the apparatus 100 may comprise a tin-based alloy, which (in addition to tin) includes one or more of the following metals: antimony, copper, lead, zinc, aluminum, arsenic, bismuth, iron. Nonlimiting examples regarding the composition of the white metal in this regard include the following:

[0042] - a tin-based alloy further comprising copper and antimony,

[0043] - a tin-based alloy further comprising copper, antimony and lead,

[0044] - a tin-based alloy further comprising copper, antimony and zinc,

[0045] - a tin-based alloy further comprising copper, antimony, lead and zinc.

[0046] According to an example, the laser assembly 125 may be arranged to emit the laser beam at a fixed predefined laser power, whereas in another example the applied laser power may be user-definable and it may be chosen from a plurality of predefined laser powers e.g. based on user input received via the III of the apparatus 100. The controller 140 may be arranged to control at least some aspects of operation of the laser assembly 125, e.g. one or more of the following: activation of emission of the laser beam 126, deactivation of emission of the laser beam 126, selection of the laser power to be applied (if applicable). As an example regarding applicable laser power(s), the applied laser power may be e.g. 3 kW or another predefined value chosen from a range from 2 to 6 kW. The laser beam 126 emitted from the laser assembly 125 may comprise a laser source (not shown in the illustrations of Figures 2 and 3) arranged to emit a light beam at a predefined wavelength (e.g. at 1000 nanometers) and a beam shaping portion 125a arranged to focus the light beam originating from the laser source in a predefined or selectable manner in order to produce the laser beam 126 for transmission from the laser assembly 125 towards the target position at the target plane of the deposition assembly 120. The laser source may comprise, for example, a laser diode and an optical fiber arranged to transmit the light output of the laser diode to the beam shaping portion 125a.

[0047] The beam shaping portion 125a may comprise a lens system including one or more lenses arranged to shape (e.g. focus) the light beam originating from the laser source in a predefined or selectable manner. In general, the beam shaping portion 125a may be arranged to shape the light beam originating from the laser source such that the cross-section of the laser beam 126 emitted from the laser assembly 125 with the target plane encompasses the target position. As an example, the beam shaping portion 125a may be arranged to shape (e.g. focus) the light beam originating from the light source such that the cross-section of the resulting laser beam 126 with the target plane has a predefined size. Herein, the cross-section of the laser beam 126 and the target plane may be referred to as a target area (on the target plane). Such beam shaping via operation of the beam shaping portion 125a serves to distribute the predefined laser power conveyed in the light beam originating from laser source over a wider area in order to provide a desired power per unit area at the target plane.

[0048] In this regard, the predefined size of the target area may be chosen, in view of the applied predefined laser power, such that power per unit area at the target plane is sufficient for generating heat that ensures melting a portion of the metal wire 122 supplied to the target point and forming a strong bond with the molten second metal and the surface of the object 150 while the power per unit area at the target plane is low enough to avoid causing damage to the surface of the object 150 at and around the target point due to excessive heat and to facilitate relatively fast cooling of the second metal deposited thereon to ensure providing high-quality coating layer 123. As an example in this regard, characteristics of the laser beam 126 may be chosen such that a temperature on the surface of the object 150 within the target area does not exceed a predefined target maximum temperature to ensure fast enough cooling of the second metal, where the target maximum temperature chosen e.g. from a range from 60 to 100 degrees Celsius. The target area is preferably larger than the cross-section of the laser beam 126 at its (conceptual) focus distance. This facilitates distributing the laser power over a widened area on the target plane, which is advantageous both in terms of limiting the heat conveyed to the surface of the object 150 and in terms of pre-heating the surface around the target position. According to a non-limiting example, when applying laser powers within the range described in the foregoing, a surface temperature within such a range may be provided by the laser beam 126 that results in a diameter of the target area being larger than a diameter of the cross-section of the laser beam 126 at its focus distance by a factor having a range from 1 .4 to 1 .8, e.g. 1 .6.

[0049] In the example illustrated in Figures 2 and 3, the target area of the predefined size is provided via the beam shaping portion 125a arranged to focus the laser beam 126 at a focus plane that is parallel with the target plane and that is suitably offset from the target plane towards the laser assembly 125. In other words, the focus plane resides between the laser assembly 125 and the target plane. The distance between the laser assembly 125 and the focus plane may be referred to as a focus distance and the distance between the focus plane and the target plane may be referred to as an offset distance. In such a scenario, the laser beam 126 emitted from the laser assembly 125 is convergent between the laser assembly 125 and the focus plane and it is divergent between the focus plane and the target plane. The offset distance that results in the predefined size of the target area on the target plane may be defined in view of the divergence of the laser beam 126 at distances (from the laser assembly 125) larger than the focus distance.

[0050] According to an example, the beam shaping portion 125a is arranged to focus the laser beam 126 at a fixed predefined focus distance. In such a scenario the offset distance that results in the predefined size of the target area may be provided via arranging the laser assembly 125 at a suitable distance from the target plane. According to another example, the beam shaping portion 125a may enable selecting the focus distance from a predefined range or from a predefined set of focus distances and the beam shaping portion 125a is arranged to focus the laser beam 126 at the selected focus distance. In such a scenario the offset distance that results in the predefined size of the target area may be provided via arranging the laser assembly 125 at a desired distance from the target plane and selecting the focus distance that results in the desired offset distance.

[0051] Typically and preferably, the target area is substantially larger than the crosssection of the metal wire supplied from the wire feeder assembly 121. Herein, the expression ‘substantially larger’ is to be construed broadly, encompassing e.g. target areas having a diameter that is larger than the diameter of the metal wire by at least by a factor having a value in a range from 1 .5 to 3. As an example in this regard, considering the exemplifying range of the wire diameters described in the foregoing, the diameter of the target area may be in a range from 3 to 6 millimeters. An advantage arising from the target area that is substantially larger than the cross-section of the metal wire is that in such an arrangement the laser beam 126 also pre-heats the surface of the object 150 around the target position before moving the target position thereon, which has been found to provide a stronger bond between the surface and the second metal deposited thereon.

[0052] The wire feeder assembly 121 and the laser assembly 125 are arranged as part of the deposition assembly 120 in fixed positions with respect to each other. In this regard, the deposition assembly 120 may comprise a frame or a body, whereas the wire feeder assembly 121 and the laser assembly 125 may be mounted to the frame or the body such that their positions in relation to each other as well as in relation to the target plane of the deposition assembly 120 and the target position therein remains fixed also during possible movement of the deposition assembly 120. In a preferred example, as also illustrated in the respective examples of Figueres 2 and 3, the laser assembly 125 may be arranged to emit the laser beam 126 substantially in the right angle with respect to the target plane, whereas the wire feeder assembly 121 may be arranged to supply the metal wire in an incident angle with respect to the target plane. In this regard, the incident angle between the direction of the metal wire supply and the target plane may be chosen, for example, from a range from 45 to 55 degrees, which results in the angle between the center axis (or main axis) of the laser beam 126 and the direction of the metal wire supply being in a range from 35 to 45 degrees.

[0053] In another example, the laser assembly 125 may be arranged to emit the laser beam 126 towards the target point in a first incident angle with respect to a normal of the target plane and the wire feeder assembly 121 may be arranged to supply the metal wire in a second incident angle with respect to the target plane. In such an arrangement the first incident angle may be chosen, for example, from a range from 0 to 15 degrees (in any direction with respect to the normal of the target plane), whereas the second incident may be chosen such that the angle between the center axis of the laser beam 125 emitted from the laser assembly 125 and the direction of the metal wire supply from the wire feeder assembly 121 is set to a suitable value, for example, in the range from 35 to 45 degrees.

[0054] Along the lines described in the foregoing, the deposition assembly 120 may be moveable with respect to the surface of the object 150 to facilitate deposition of the coating layer 123 on its surface, where the movement by invoked via operation of the positioning apparatus 130. The movement of the deposition assembly 120 may involve translational and / or rotational movement with respect to the surface of the object 150. in this regard, the positioning assembly 130 may comprise an actuation mechanism for moving the deposition assembly 120 under control of the controller 140. As an example in this regard, the actuation mechanism for moving the deposition assembly 120 may comprise a robot arm and the deposition assembly 120 may be mounted to the robot arm, the positioning assembly 130 thereby arranged to move the deposition assembly 120 via operation of the robot arm under control of the controller 140.

[0055] Along the lines described in the foregoing, the apparatus may optionally comprise the holding assembly 150, which is provided for holding the object 150 during deposition of the coating layer 123 on its surface via operation of the apparatus 100 and, therefore, the holding assembly 110 may comprise an attachment mechanism for detachably mounting the object 150 to the holding assembly 110. As also described in the foregoing, the holding assembly 110 may be moveable in order to move the surface of the object 150 temporarily mounted to the holding assembly 110 with respect to the deposition assembly 120. Like in the case of the deposition assembly 120, the movement induced to the surface of the object 150 via movement of the holding assembly 110 may be translational and / or rotational. The apparatus 100 may be provided for depositing the coating layer 123 comprising the second metal on surfaces of objects of certain size and / or shape and, consequently, physical and operational characteristics of the holding assembly 110 and the attachment mechanism provided therefor may vary accordingly. The positioning assembly 130 may comprise an actuation mechanism for moving the surface of the object 150 temporarily mounted to the holding assembly 150 and due to variation in physical and operational characteristic of the holding assembly 110 in different embodiments also the physical and operational characteristics of the actuation mechanism may vary accordingly from one embodiment to another.

[0056] In a particular example, the apparatus 100 is provided for depositing the coating layer 123 on the inner surface of a plain bearing within a certain range of sizes (e.g. in terms of the diameter and width of its inner surface), where the second metal applied for the coating layer 123 comprises the white metal described in the foregoing. In particular, the plain bearing under consideration may be one intended for use in a powertrain of a marine vessel, it may be made of metal such as cast iron, steel, alloy steel, stainless steel, bronze, etc. and it may be considerably large in size (having a diameter e.g. in a range of several meters). In such configuration of the apparatus 100, the (optional) holding assembly 110 and the attachment mechanism provided therefor may be arranged to facilitate temporary mounting of the plain bearing thereto such that its inner surface remains exposed in a manner that allows bringing the deposition assembly 120 to a position where its target position is on the inner surface of the plain bearing. Moreover, the holding assembly 110 in such configuration of the apparatus 100 may allow at least rotational motion of the plain bearing about its center axis, which enables moving the inner surface of plain bearing with respect to the deposition assembly 120 brought into its proximity via rotating the plain bearing.

[0057] Hence, the operation of the apparatus 100 may involve the controller 140 operating the positioning assembly 130 and the deposition assembly 120 to carry out a deposition procedure as follows:

[0058] 1. operate the positioning assembly 130 to bring the deposition assembly 120 in a position where the target position is overlaid with a position of the inner surface of the plain bearing at a first edge of the inner surface, 2. operate the positioning assembly 130 to rotate the plain bearing by one full round while keeping the deposition assembly 120 stationary and at the same operate the deposition assembly 120 to deposit the second metal on the surface,

[0059] 3. after completing the full round, move the deposition assembly 120 such that the target position is moved by a predefined amount towards a second edge of the inner surface,

[0060] 4. in case the second edge of the inner surface has been reached, finish the deposition procedure; in case the second edge of the inner surface has not been reached, repeat steps 2 to 4.

[0061] The deposition procedure described via the steps 1 to 4 above serves to define an outline of an exemplifying manner of using the apparatus 100, whereas various details associated with respective operations captured in the steps 1 to 4 may be carried out in consideration of the more detailed examples concerning structure and operation of the apparatus 100 provided in the foregoing. Moreover, the deposition procedure outlined via the steps 1 to 4 readily generalizes into a deposition procure applicable for objects different from the plain bearing via applying modifications that are apparent in view of the examples detailed examples concerning structure and operation of the apparatus 100 provided in the foregoing.

[0062] The non-limiting examples provided in the foregoing describe operation of the deposition apparatus 100 for depositing the coating layer 123 of the second metal on a surface of the object 150 comprising the first metal. In this regard, the apparatus 100 and the object 150 may considered to constitute a deposition arrangement for depositing the coating layer 123 on the surface of the object 150. Along the lines described above, the apparatus 100 may be embodied for depositing the coating layer 123 on a surface of an object 150 of a certain shape and / or size, whereas in a particular example the object 150 comprises a plain bearing having its size within a predefined size range. In such an embodiment, the holding assembly 110 (if included in the apparatus 100) is arranged to hold a plain bearing having its size within the predefined size range such that the inner surface of the plain bearing remains exposed in a manner that allows bringing the deposition assembly 120 to a position where its target position resides on the inner surface.

[0063] Along similar lines, the non-limiting examples provided in the foregoing that describe operation of the deposition apparatus 100 for depositing the coating layer 123 of the second metal on a surface of the object 150 comprising the first metal may be considered to disclose use of the apparatus 100 for depositing the coating layer 123 on the surface of the object 150, e.g. use of the apparatus 100 for depositing the coating layer 123 on a surface of the object 150 having a certain shape and / or size. In a particular example, the use may concern use of the apparatus 100 for depositing the coating layer 123 on an inner surface of a plain bearing having its size within a predefined size range e.g. in accordance with the examples provided in the foregoing.

[0064] Figure 4 schematically depicts some aspects of structure and operation of the deposition assembly 120 according to another example, where the laser assembly 125 is arranged to emit a divergent laser beam 127, whose crosssection with the target plane has the predefined size. In this regard, the beam shaping portion 125a of the laser assembly 125 may be arranged to modify focus of the light beam originating from the laser source such that the laser beam 127 emitted from the laser assembly 125 is divergent throughout. According to an example, the beam shaping portion 125a is arranged to introduce at a fixed predefined divergence to the laser beam 127 emitted from the laser assembly 125. In such a scenario, the distance between the laser assembly 125 and the target plane that results in the predefined size of the target area may be provided via arranging the laser assembly 125 at a suitable distance from the target plane. According to another example, the beam shaping portion 125a may enable selecting the divergence of the emitted laser beam 127 from a predefined range or from a predefined set of divergence values and the beam shaping portion 125a is arranged to diverge the emitted laser beam 127 accordingly. In such a scenario, the distance between the laser assembly 125 and the target plane that results in the predefined size of the target area may be provided via arranging the laser assembly 125 at a desired distance from the target plane and selecting the divergence of the laser beam 127 such that the target area of the predefined size is provided at the target plane.

[0065] Figure 5 schematically depicts some aspects of structure and operation of the deposition assembly 120 according to a further example, where the laser assembly 125 is arranged to emit a substantially coherent laser beam 128, whose cross-section has the predefined size throughout. In this regard, the beam shaping portion 125a of the laser assembly 125 may be arranged to modify the width of the light beam originating from the laser source such that the coherent laser beam 128 of desired beam width is emitted from the laser assembly 125. According to an example, the beam shaping portion 125a is arranged to shape the light beam originating from the laser source from its original beam width into a fixed predefined (different) beam width for emission as the laser beam 128. According to another example, the beam shaping portion 125 may enable selecting the beam width for the laser beam 128 emitted from the laser assembly 125 from a predefined range or a predefined set of beam widths and the beam shaping portion 125a is arranged to modify the beam width for the emitted laser beam 128 accordingly. In scenarios the distance between the laser assembly 125 and the target plane may be chosen substantially freely due to the constant cross-section of the coherent laser beam 128.

[0066] The operation or use of the apparatus 100 for depositing the coating layer 123 of the second metal on the surface of the object 150 comprising the first metal may be, alternatively, described as steps of a method. As a non-limiting example in this regard, Figure 6 illustrates a method 200 for depositing the coating layer 123 comprising the second metal on the surface of the object 150 comprising the first metal, wherein the method 200 comprises the following steps:

[0067] - supply, from a deposition assembly 120, the metal wire 122 comprising the second metal to the target position of the target plane of the deposition assembly 120 (block 202);

[0068] - emit, from the deposition assembly 120, the laser beam 126, 127, 128 towards the target position so as to melt a portion of the metal wire 122 supplied thereto due to heat generated by the laser beam 126, 127, 128, said emitting comprising shaping a light beam originating from a laser source into the laser beam 126, 127, 128 whose cross-section with the target plane encompasses the target position (block 204); and

[0069] - move at least one of the the object 150 and the deposition assembly 120 to move the target position along the surface of the object 150 in order to deposit the coating layer 123 on said surface (block 206).

[0070] The respective operations of the method 200 described with reference to blocks 202 to 206 may be embodiment, varied and / or complemented in a number of ways without departing from the scope of the method 200, for example in accordance with the examples described in the foregoing with references to the apparatus 100, mutatis mutandis.

[0071] The method 200 may be carried out, for example, via a control entity such as the controller 140 described in the foregoing operating an actuation arrangement such as the positioning assembly 130 described in the foregoing to move at least one of the surface of the object 150 and the deposition assembly 120 with respect to one another to cause movement of the target position along the surface of the object 150, where the control entity may further operate the deposition assembly 120 to feed the metal wire 122 and the emit the laser beam 126, 127, 128 along with the movement of target position on the surface to deposit the coating layer 123 thereon. The method 200 may be applicable, for example, for depositing the coating layer 123 comprising the second metal on the surface of a plain bearing having its size within a predefined size range and wherein the surface to be provided with the coating 123 comprises an inner surface of the plain bearing.

[0072] Figure 7 illustrates a block diagram of some components of an apparatus 300 that may be employed to implement the controller 140. The apparatus 300 comprises a processor 310 and a memory 320. The memory 320 may store data and computer program code 325. The apparatus 300 may further comprise communication means 330 for wired or wireless communication with other apparatuses. The apparatus 300 may further comprise user I / O (input / output) components 340 that may be arranged, together with the processor 310 and a portion of the computer program code 325, to provide a user interface for receiving input from a user and / or providing output to the user. In particular, the user I / O components may include user input means, such as one or more keys or buttons, a keyboard, a touchscreen or a touchpad, etc. The user I / O components may include output means, such as a display or a touchscreen. The components of the apparatus 300 are communicatively coupled to each other via a bus 350 that enables transfer of data and control information between the components.

[0073] The memory 320 and a portion of the computer program code 325 stored therein may be further arranged, with the processor 310, to cause the apparatus 300 to perform at least some aspects of operation of the controller 140. The processor 310 is configured to read from and write to the memory 320. Although the processor 310 is depicted as a respective single component, it may be implemented as respective one or more separate processing components. Similarly, although the memory 320 is depicted as a respective single component, it may be implemented as respective one or more separate components, some or all of which may be integrated / removable and / or may provide permanent I semi-permanent / dynamic / cached storage.

[0074] The computer program code 325 may comprise computer-executable instructions that implement at least some aspects of operation of the controller 140 when loaded into the processor 310. As an example, the computer program code 325 may include a computer program comprising one or more sequences of one or more instructions. The processor 310 is able to load and execute the computer program by reading the one or more sequences of one or more instructions included therein from the memory 320. The one or more sequences of one or more instructions may be configured to, when executed by the processor 310, cause the apparatus 300 to perform at least some aspects of operation of the controller 140. Hence, the apparatus 300 may comprise at least one processor 310 and at least one memory 320 including the computer program code 325 for one or more programs, the at least one memory 320 and the computer program code 325 configured to, with the at least one processor 310, cause the apparatus 300 to perform at least some aspects of operation of the controller 140.

[0075] The computer program code 325 may be provided e.g. a computer program product comprising at least one computer-readable non-transitory medium having the computer program code 325 stored thereon, which computer program code 325, when executed by the processor 310 causes the apparatus 300 to perform at least some aspects of operation of the controller 140. The computer-readable non-transitory medium may comprise a memory device or a record medium that tangibly embodies the computer program. As another example, the computer program may be provided as a signal configured to reliably transfer the computer program.

[0076] Reference(s) to a processor herein should not be understood to encompass only programmable processors, but also dedicated circuits such as field- programmable gate arrays (FPGA), application specific circuits (ASIC), signal processors, etc.

Claims

CLAIMS1 . An apparatus (100) for depositing a coating layer (123) of a second metal on a surface of an object (150) comprising a first metal, the apparatus (100) comprising: a deposition assembly (120) comprising a wire feeder assembly (121 ) arranged to supply metal wire (122) comprising the second metal to a target position on a target plane of the deposition assembly (120), and a laser assembly (125) arranged to emit a laser beam (126, 127, 128) towards the target position so as to melt a portion of the metal wire (122) supplied thereto due to heat generated by the laser beam (126, 127, 128); a positioning assembly (130) for moving at least one of the object (150) and the deposition assembly (120) in order to move the target position in relation to said surface of the object (150); and a controller (140) arranged to control the positioning assembly (130) such that the target position is moved along said surface in order to deposit the coating layer (123) on said surface, wherein the laser assembly (125) comprises a beam shaping portion (125a) arranged to shape a light beam originating from a laser source into the laser beam (126, 127, 128) whose cross-section with the target plane encompasses the target position.

2. An apparatus (100) according claim 1 , wherein the cross-section of the laser beam (126, 127, 128) with the target plane has a predefined size.

3. An apparatus (100) according to claim 1 or 2, wherein the beam shaping assembly (125a) is arranged to focus the laser beam (126) at a focus planethat is offset from the target plane and that resides between the laser assembly (125) and the target plane.

4. An apparatus (100) according to claim 3, wherein a distance between the focus plane and the target plane is selected such that cross-section of the laser beam (126) with the target plane has a predefined size.

5. An apparatus (100) according to any of claims 1 to 4, wherein the crosssection of the laser beam (126, 127, 128) with the target plane is larger than a cross section of the laser beam (126, 127, 128) at its focus distance.

6. An apparatus (100) according to any of claims 1 to 5, wherein a diameter of the cross-section of the laser beam (126, 127, 128) with the target plane is larger than a diameter of a cross section of the laser beam (126, 127, 128) at its focus distance by a factor having a value in a range from 1 .4 to 1.8.

7. An apparatus (100) according to any of claims 1 to 6, wherein the crosssection of the laser beam (126, 127, 128) with the target plane is substantially larger than the cross-section of the metal wire (122) supplied by the wire feeder assembly (121 ).

8. An apparatus (100) according to any of claims 1 to 7, wherein a diameter of the cross-section of the laser beam (126, 127, 128) with the target plane is larger than a diameter of the cross-section of the metal wire (122) supplied by the wire feeder assembly (121 ) by a factor having a value in a range from 1 .5 to 3.

9. An apparatus (100) according to any of claims 1 to 8, wherein the laser assembly is arranged to emit the laser beam (126, 127, 128) at a predefined laser power.

10. An apparatus (100) according to any of claims 1 to 9, wherein the laser assembly is arranged to emit the laser beam (126, 127, 128) at a laser power that is within a range from 2.5 to 5 kW.

11. An apparatus (100) according to any of claims 1 to 10, wherein the wire feeder assembly (111 ) is arranged to supply the metal wire (122) in an incident angle with respect the target plane and the laser assembly (112) is arranged to emit the laser beam (126, 127, 128) substantially in a right angle with respect to the target plane.

12. An apparatus (100) according to claim 11 , wherein the incident angle between a direction of the metal wire supply and the target plane is in a range from 45 to 55 degrees.

13. An apparatus (100) according to any of claims 1 to 12, wherein the wire feeder assembly (121 ) is arranged to supply the metal wire (122) at a user- definable speed.

14. An apparatus (100) according to any of claims 1 to 13, wherein the wire feeder assembly (121 ) is arranged to supply the metal wire at a speed that is in a range from 1 to 4 meters per minute.

15. An apparatus (100) according to any of claims 1 to 14, wherein the metal wire (122) has a thickness in a range from 1 to 2.5 millimeters.

16. An apparatus (100) according to any of claims 1 to 15, wherein the second metal has a melting point lower than that of the first metal.

17. An apparatus (100) according to any of claims 1 to 16, wherein the second metal comprises white metal.

18. An apparatus (100) according to claim 16 or 17, wherein the second metal comprises a tin-based alloy that comprises one or more of the following: lead, copper, antimony, zinc.

19. An apparatus (100) according to any of claims 1 to 18, wherein the controller (140) is arranged to operate the positioning assembly (130) to move the target position on said surface along a user-definable path.

20. An apparatus (100) according to any of claims 1 to 19, wherein the controller (140) is arranged to operate the positioning assembly (130) to move the target position on said surface at a user-definable movement speed.

21. An apparatus (100) according to claims 1 to 20, wherein the controller (140) is arranged to operate the positioning assembly (130) to move the target position on said surface at a movement speed that is in a range from 2 to 4 meters per minute.

22. An apparatus (100) according to any of claims 1 to 21 , further comprising a holding assembly (110) for holding the object (150), wherein the holding assembly (110) is moveable with respect to the deposition assembly (110) and wherein the controller (140) is arranged to control the positioningassembly (130) to move the holding assembly (110) in order to move the target position in relation to said surface of the object (150).

23. An apparatus (100) according to any of claims 1 to 21 , wherein the deposition assembly (110) is moveable with respect to the object (150) and wherein the controller (140) is arranged to control the positioning assembly (130) to move the deposition assembly (120) in order to move the target position in relation to said surface of the object (150).

24. An apparatus (100) according to any of claims 1 to 21 , further comprising a holding assembly (110) for holding the object (150), wherein the holding assembly (110) is moveable with respect to the deposition assembly (120) and the deposition assembly (120) is moveable with respect to the holding assembly (110) and wherein the controller (140) is arranged to control the positioning assembly (130) to move the holding assembly (110) and the deposition assembly (120) in order to move the target position in relation to said surface of the object (150).

25. An apparatus (100) according to any of claims 1 to 21 , further comprising a holding assembly (110) for holding the object (150).

26. An apparatus (100) according to claim 25, wherein the holding assembly (110) is moveable with respect to the deposition assembly (110) and wherein the positioning assembly (130) is provided for moving at least one of the holding assembly (110) and the deposition assembly (120) in order to move the target position in relation to said surface of the object (150).

27. An apparatus (100) according to any of claims 22 and 24 to 26, wherein the holding assembly (110) is arranged for temporarily mounting a plain bearing having a size withing a predefined size range such that its innersurface remains exposed in a manner that enables bringing the deposition assembly (120) to a position where its target position resides on an inner surface of the plain bearing.

28. An arrangement comprising an apparatus (100) according to any of claims 1 to 27 and the object (150).

29. An arrangement comprising an apparatus (100) according to any of claims 25 to 27 and the object (150), wherein the object is temporarily mounted to the holding assembly (110).

30. A method (200) for depositing a coating layer (123) of a second metal on a surface of an object (150) comprising a first metal, the method (200) comprising: supplying (202), from a deposition assembly (120), a metal wire (122) comprising the second metal to a target position of a target plane of a deposition assembly (120); emitting (204), from the deposition assembly (120), a laser beam (126, 127, 128) from the deposition assembly (120) towards the target position so as to melt a portion of the metal wire (122) supplied thereto due to heat generated by the laser beam (126, 127, 128), said emitting comprising shaping a light beam originating from a laser source into the laser beam (126, 127, 128) whose cross-section with the target plane encompasses the target position; and moving (206) at least one of the object (150) and the deposition assembly (120) to move the target position along a surface of said object (150) in order to deposit the coating layer (123) on said surface.31 . A method (200) according claim 30, wherein the cross-section of the laser beam (126, 127, 128) with the target plane has a predefined size.

32. A method (200) according to claim 30 or 31 , wherein said shaping comprises focusing the laser beam (126) at a focus plane that is offset from the target plane and that resides between the laser assembly (125) and the target plane.

33. A method (200) according to claim 32, wherein a distance between the focus plane and the target plane is selected such that the cross-section of the laser beam (126) with the target plane has a predefined size.

34. A method (200) according to any of claims 30 to 33, wherein the crosssection of the laser beam (126, 127, 128) with the target plane is larger than a cross section of the laser beam (126, 127, 128) at its focus distance.

35. A method (200) according to any of claims 30 to 34, wherein a diameter of the cross-section of the laser beam (126, 127, 128) with the target plane is larger than a diameter of a cross section of the laser beam (126, 127, 128) at its focus distance by a factor having a value in a range from 1 .4 to 1 .8.

36. A method (200) according to any of claims 30 or 35, wherein the crosssection of the laser beam (126, 127, 128) with the target plane is substantially larger than the cross-section of said metal wire (122).

37. A method (200) according to any of claims 30 to 36, wherein a diameter of the cross-section of the laser beam (126, 127, 128) with the target plane is larger than a diameter of the cross-section of the metal wire (122) suppliedby the wire feeder assembly (121 ) by a factor having a value in a range from 1 .5 to 3.

38. A method (200) according to any of claims 30 to 37, wherein the laser beam (126, 127, 128) is emitted at a predefined laser power.

39. A method (200) according to any of claims 30 to 38, wherein the laser beam (126, 127, 128) is emitted at laser power that is within a range from 2.5 to 5 kW40. A method (200) according to any of claims 30 to 39, wherein the metal wire (122) in supplied in an incident angle with respect the target plane and the laser beam (126, 127, 128) is emitted substantially in a right angle with respect to the target plane.41 . A method (200) according to claim 40, wherein the incident angle between a direction of the metal wire supply and the target plane is in a range from 45 to 55 degrees.

42. A method (200) according to any of claims 30 to 41 , wherein the metal wire (122) is supplied at a user-definable speed.

43. A method (200) according to any of claims 30 to 42, wherein the metal wire (122) is supplied at a speed that is in a range from 1 to 4 meters per minute.

44. A method (200) according to any of claims 30 to 43, wherein the metal wire (122) has a thickness in a range from 1 to 2.5 millimeters.

45. A method (200) according to any of claims 30 to 44, wherein the second metal has a melting point lower than that of the first metal.

46. A method (200) according to any of claims 30 to 45, wherein the second metal comprises white metal.

47. A method (200) according to claim 45 or 46, wherein the second metal comprises a tin-based alloy that comprises one or more of the following: lead, copper, antimony, zinc.

48. A method (200) according to any of claims 30 to 47, wherein the target position is moved on said surface along a user-definable path.

49. A method (200) according to any of claims 30 to 48, wherein the target position is moved on said surface at a user-definable movement speed.

50. A method (200) according to any of claims 30 to 49, wherein the movement speed is in a range from 2 to 4 meters per minute.51 . A method (200) according to any of claims 30 to 50, comprising moving the object (150) with respect to the deposition assembly (110) to move the target position along said surface of the object (150).

52. A method (200) according to any of claims 30 to 50, comprising moving the deposition assembly (120) with respect to the object (150) to move the target position along said surface of the object (150).

53. A method (200) according to any of claims 30 to 50, comprising moving the object (150) with respect to the deposition assembly (110) and moving the deposition assembly (120) with respect to the object (150) to move the target position along said surface of the object (150).

54. A method (200) according to any of claims 30 to 53, wherein the object (150) comprises a plain bearing having its size within a predefined size range and wherein said surface comprises an inner surface of the plain bearing.

55. A method (200) according to claims 51 or 53, further comprising temporarily mounting the object (150) to a holding assembly (110) provided for holding the object (150) and wherein moving the object (150) with respect to the deposition assembly (120) comprises moving the holding assembly (110).

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