Method for coating a brake disc made of grey cast iron or steel

Abstract

The invention relates to a method for coating a brake disc (1) made of gray cast iron or steel, wherein the brake disc (1) has a base body and at least one disc body (11) extending radially from the base body perpendicular to an axis of rotation of the brake disc (1), which disc body has a face whose face normal is parallel to the axis of rotation. A coating is applied to the face of the disc body (11) by means of a tool in laser cladding welding, which coating consists of at least one layer applied to the face of the disc body (11). During the application of the at least one layer, the tool is moved relative to the disc body (11) at least for the main duration of the method with a track offset (sv) and a feed speed (v), wherein at least one laser beam (14) and a powder material to be melted with a powder mass flow are supplied to the disc body (11) by means of the tool. The invention is characterized in that the track offset (sv) of the tool is temporarily changed during the application of the at least one layer.

Description

Technical Field

[0001] The present invention relates to a method for coating a brake disc made of gray cast iron or steel, wherein the brake disc has a substrate and at least one disc-shaped body extending radially from the substrate perpendicular to the rotation axis of the brake disc, the disc-shaped body having a surface whose surface normal is parallel to the rotation axis, wherein a coating is applied to the surface of the disc-shaped body by laser cladding using a tool, the coating consisting of at least one layer applied to the surface of the disc-shaped body, wherein during the application of the at least one layer, the tool has a trajectory offset and a feed rate relative to the disc-shaped body for at least the main duration of the method, and wherein at least one laser beam and a powder material to be melted with a powder mass flow are supplied to the disc-shaped body by the tool. Background Technology

[0002] The purpose of coating brake discs is to significantly reduce fine dust emissions generated during vehicle braking, thereby minimizing the environmental impact. The coating is applied to one or more surfaces of the disc-shaped body of the brake disc. First, a layer of stainless steel is applied, which is then covered by a composite material consisting of an iron alloy matrix and embedded hard particles. Both layers are applied to the respective substrates using laser cladding welding.

[0003] During coating, the brake disc to be coated is rotated with its axis of rotation vertically oriented. Simultaneously, a tool is moved radially across the substrate, directing both the coating material and the laser beam onto the substrate. If the tool moves radially from the inside out, it moves to the outer diameter of the brake disc during the application of the first layer. Similarly, the application of the second layer is accomplished by moving the tool to the outer diameter of the brake disc.

[0004] For quality reasons, uniform layer thickness is desired during laser cladding. The layer thickness is determined by the tool feed rate (Vorschub) and trajectory offset, as well as the powder mass flow supplied to the brake disc through the tool.

[0005] Within the scope of this invention, "feed speed v" should be understood as the speed of a point, or the speed of a laser beam generated by the tool, on the substrate, which depends on the distance of that point from the center of the brake disc and its rotational speed. The feed speed is defined as follows: v = 2πr^n, where v = feed rate r = distance from the center of the brake disc n = rotational speed of the brake disc Within the scope of this invention, "trajectory offset" is understood as the distance traveled by a tool or a laser beam generated by the tool relative to the center of the brake disc during one revolution of the brake disc, when observed radially while performing linear motion. Typically, the trajectory offset points radially outward.

[0006] "Powder mass flow" can be understood as the mass of powder material to be melted supplied to the brake disc via a tool within a specific unit of time.

[0007] However, laser cladding welding presents the following problems: damage due to so-called "overspray" can occur at the coated workpiece in the form of bottom erosion under corrosive conditions, and may also occur at the coating equipment. Overspray occurs particularly when the tool is located radially outside the surface to be coated at the beginning and end of the coating process.

[0008] "Overspraying" is understood to refer to the following area, located radially adjacent to the surface to be coated, on a brake disc or coating device, where heated hard particles impact and adhere to or melt into the area when a layer is applied, especially when a second layer is applied via laser cladding. These hard particles are extremely difficult to remove, and sometimes impossible to remove at all.

[0009] Overspray can be overcome by reducing the radial overshoot of the tool. However, this will compromise the coating quality, especially as it will result in insufficient layer thickness at the edge areas of the surface to be coated.

[0010] DE102021214946A1 describes a brake disc for a friction brake in a motor vehicle, having a friction section with a friction surface and a fixed section for vehicle-side fixation. The friction section and fixed section are constructed on a substrate made of gray cast iron or steel. In the friction section, an anti-wear protective layer is applied to the substrate as a friction surface by laser cladding welding. This anti-wear protective layer extends beyond the friction surface into an angled region relative to the friction surface and terminates there. In this angled region of the substrate, the anti-wear protective layer is applied covertly and without gaps to the substrate. A corrosion-resistant protective layer may be provided on the surface section outside the friction surface, covering the anti-wear protective layer in the angled region. Summary of the Invention

[0011] This invention aims to provide a method for coating brake discs made of gray cast iron or steel, which achieves high coating quality. Specifically, even with measures to reduce overspray, a sufficient layer thickness should be achieved across the entire coating area of ​​the brake disc.

[0012] This task is accomplished by the method according to the invention for coating brake discs made of gray cast iron or steel. Advantageous embodiments and improvements of the invention can be derived from the remaining embodiments.

[0013] This invention is based on a method for coating a brake disc made of gray cast iron or steel. The brake disc has a substrate and at least one disc-shaped body extending radially from the substrate perpendicular to the rotation axis of the brake disc. The disc-shaped body has a surface whose normal is parallel to the rotation axis. A coating is applied to the surface of the disc-shaped body by laser cladding using a tool. The coating consists of at least one layer applied to the surface of the disc-shaped body. During the application of the at least one layer, the tool (at least for the main duration of the method) has a trajectory offset and feed rate relative to the disc-shaped body, wherein at least one laser beam and a powder material to be melted with a powder mass flow are supplied to the disc-shaped body via the tool.

[0014] The present invention now proposes to temporarily change the trajectory offset of the tool during the application of the at least one layer.

[0015] Therefore, the trajectory offset is no longer constant across the entire radial travel of the tool as before; instead, it is changed at least once. This feature provides a prerequisite for coating the brake disc with sufficient layer thickness over the entire area to be coated, even if the tool should have a radial overshoot relative to the surface to be coated due to the selected start and end positions. In particular, the trajectory offset is reduced in selected areas of the brake disc. In this way, more powder material can be supplied to these selected areas.

[0016] According to the first improvement, during the application of the at least one layer, the feed rate and / or the powder mass flow rate are additionally varied. This improvement allows for more precise influence on the layer thickness in a selected region. In particular, to increase the supplied powder material, the feed rate can be reduced in the selected region, i.e., the rotational speed of the brake disc can be reduced. The powder mass flow rate can then be increased to increase the supplied powder material.

[0017] A highly advantageous construction of this invention is characterized in that, after passing through a first radial travel segment or after experiencing a first time period, the tool moves with a constant trajectory offset of a specific value on a second radial travel segment corresponding to most of the radial extension dimension of the disc-shaped body. Here, a third radial travel segment or a third time period follows the second radial travel segment, wherein the trajectory offset of the tool during the first radial travel segment or the first time period, and during the third radial travel segment or the third time period, is lower than the value of the trajectory offset in the second radial travel segment.

[0018] This design allows for highly precise coordination of the process with critical areas near the radial inner and outer edges. To minimize overspray, the tool should not be positioned radially outside or reaching the disk body during the coating process. However, this results in a drawback: the laser diameter cannot be fully utilized. Since the powder mass flow is concentric with the laser supply, this also affects the amount of powder material supplied. These characteristics, in particular, enable the supply and melting of more powder material in critical areas.

[0019] A similar positive effect can be achieved by having the tool move at a constant feed rate of a specific value in a second radial stroke segment corresponding to most of the radial extension dimension of the disc-shaped body, after passing through a first radial stroke segment or after experiencing a first time period. Here, a third radial stroke segment or a third time period follows the second radial stroke segment, wherein the feed rate of the tool during the first radial stroke segment or during the first time period, and during the third radial stroke segment or during the third time period, is lower than the feed rate value in the second radial stroke segment.

[0020] This improvement also helps to achieve uniform coating of the disc body along its entire radial length. In particular, by reducing the feed rate in critical areas while maintaining a constant powder mass flow, more powder material can be brought onto the disc body and melted.

[0021] According to another configuration of the method, the tool supplies a constant powder mass flow of a specific value to the disc-shaped body in a second radial stroke segment corresponding to most of the radial extension dimension of the disc-shaped body, after passing through a first radial stroke segment or after experiencing a first time period. Here, a third radial stroke segment or a third time period is connected after the second radial stroke segment, wherein the supplied powder mass flow during the first radial stroke segment or the first time period and during the third radial stroke segment or the third time period is higher than the value of the powder mass flow supplied in the second radial stroke segment. It is also possible to apply more powder material to the disc-shaped body and melt it in critical areas.

[0022] It should be noted that the trajectory offset, feed rate, and powder mass flow can not only change continuously over a specific time period, but can also change suddenly at a specific point in time.

[0023] According to an improvement, the tool is positioned in the starting position when applying the at least one layer and / or moves radially beyond the corresponding substrate to be coated to such an extent that at most half of the laser spot generated by the laser beam of the tool extends radially beyond the inner or outer diameter of the disc-shaped body. This helps to reduce overspray, while still making full use of the tool's range of action in the areas of the inner and outer edges.

[0024] In particular, it is considered suitable in this improved embodiment that the tool is positioned in the starting position when applying the at least one layer and / or moves radially beyond the corresponding substrate to be coated to such an extent that the laser spot generated by the laser beam of the tool is radially located within the disc-shaped body and its outer diameter is radially adjacent to the inner or outer diameter of the disc-shaped body.

[0025] This results in a significant reduction in overspray, and in some cases, even avoidance of overspray altogether. Meanwhile, good coating quality can still be achieved using appropriate tools.

[0026] In another highly advantageous construction, it is proposed that at the beginning or end of the application of the at least one layer, the trajectory offset of the tool is set to zero for at least one revolution of the disc-shaped body. It has been shown that this results in a coating with very high quality, even in edge regions.

[0027] This can be further improved if the trajectory offset of the tool is set to zero during the three, four, or five rotations of the disc-shaped body at the start and / or end of the application of the at least one layer.

[0028] Finally, it should be reiterated that the coating applied to the disc-shaped body of the brake disc by laser cladding consists of at least one layer. In other words, it is conceivable that the applied coating may consist of one, two, or multiple layers, which are applied in stacks.

[0029] Each of the layers may be composed of metal, metal alloy, metal matrix with embedded hard particles, or metal alloy matrix with embedded hard particles.

[0030] For example, it is conceivable that the coating consists of two layers. Here, the first layer may be made of stainless steel, and the second layer applied to the first layer may be a composite material consisting of an iron alloy matrix and embedded hard particles.

[0031] When applying the first and second layers, the process parameters that have proven particularly suitable for achieving high coating quality are: when applying the first layer, the trajectory offset is in the range of about 0.30 mm / revolution to about 0.45 mm / revolution, preferably about 0.37 mm / revolution, during the second radial stroke segment with a constant trajectory offset; and when applying the second layer, the trajectory offset is in the range of about 0.55 mm / revolution to about 0.75 mm / revolution, preferably about 0.64 mm / revolution. Here, at the beginning and end of coating (i.e., before and after the second time period for the second radial stroke segment of the tool with a constant trajectory offset), the trajectory offset is set to zero during three revolutions.

[0032] By means of the method according to the invention, the layer thickness at the coating inlet and outlet in the radial direction is increased. This allows these areas to be re-processed by grinding after coating, resulting in a significant improvement in appearance. Brake discs coated in a conventional manner have rough coating inlets and outlets, while brake discs coated according to the method according to the invention exhibit a metallic appearance in these areas, with a 45° angled and less rough coating inlet and outlet derived from the coating process.

[0033] Furthermore, the existing sharp-edged burrs can be removed through possible subsequent processing. The absence of these burrs significantly improves operations performed by workers, as well as in subsequent customer service.

[0034] A preferred embodiment of the invention is shown in the accompanying drawings, and is explained in detail in the following description with reference to the drawings. Other features and advantages of the invention also become clear from this. The same reference numerals (even in different drawings) refer to the same, similar, or functionally identical components. Corresponding or comparable features and advantages are achieved herein, even if not repeatedly described or referenced. The drawings are not drawn to scale, or at least not always to scale. In some drawings, scale or spacing may be exaggerated to more clearly highlight the features of the embodiments. Attached Figure Description

[0035] The following are illustrated in detail: Figure 1 A blank of a brake disc suitable for the method is shown in a highly schematic, cross-sectional illustration. Figure 2 The illustration shows the method in the first embodiment, wherein the disc-shaped body of the brake disc is coated by radial movement of a tool from the inside to the outside; Figure 3 Shown in accordance with Figure 2 A diagram illustrating the change in trajectory offset during brake disc coating; Figure 4 Shown in accordance with Figure 2 A diagram illustrating the change in feed rate during brake disc coating; Figure 5 The illustration shows the method in the second embodiment, wherein the disc-shaped body of the brake disc is coated by radial movement of a tool from the inside to the outside; Figure 6 Shown in accordance with Figure 5 A diagram illustrating the change in track offset during the coating of the brake disc. Detailed Implementation

[0036] exist Figure 1 The diagram shows the outline of a blank for a brake disc 1 that can serve as a starting point for the method described. This diagram is highly schematic and is retained for subsequent figures. The brake disc 1 is made of gray cast iron. The brake disc has a hub-shaped base 10. A disc-shaped body 11 extends radially from the base 10. Only areas essential for understanding the invention are shown in the brake disc 1.

[0037] The base 10 has a basin-shaped structure and is used to fix the brake disc 1 to a wheel bracket (not shown) of the motor vehicle. The base 10 is connected to the disc-shaped body 11 via a groove-shaped recess 12 (which serves as a heat balance groove). The disc-shaped body 11 has a surface 11a, the normal of which is parallel to the axis of rotation D of the brake disc 1. Surface 11a transitions radially outward into an edge surface 11b and radially inward into an edge surface 11c. Edge surfaces 11b and 11c occupy an angle α of approximately 90 degrees (preferably 90 degrees) with surface 11a. The disc-shaped body 11 defines the outer diameter d2 of the brake disc 1 radially outward and the inner diameter d1 of the brake disc 1 radially inward. Since only half of the brake disc 1 is shown horizontally, there is another surface of the disc-shaped body 11 opposite to surface 11a. The method described below also applies to this surface.

[0038] The blank of the brake disc 1 is now coated in laser cladding, wherein the surface 11a of the disc body 11 is provided with a coating consisting of two layers.

[0039] exist Figure 2 The diagram illustrates one stage of the coating method, in which a first layer B1 has been applied to surface 11a using tool 13. To coat a second layer B2 (which is similar to the coating of the first layer B1), a laser beam 14 is directed onto the corresponding substrate using tool 13, and powder material p with a specific powder mass flow is supplied to the laser beam as the coating material. In this embodiment, tool 13 moves radially (preferably from the inside out) with a trajectory offset sv, while the brake disc 1 to be coated rotates about the rotation axis D at a specific rotational speed n.

[0040] The first layer, B1, is made of stainless steel. This stainless steel is preferably austenitic or ferritic. For example, it is conceivable that the first layer is made of austenitic chromium-nickel-molybdenum steel, having material properties similar to those of 1.4404 material according to EN10027-2 or 316L material according to AISI standards. However, depending on the material properties of the brake disc, it is also conceivable and has proven advantageous that the first layer is made of ferritic stainless steel, having material properties similar to those of 1.4016 material according to DIN EN10027-2 or 430L material according to AISI standards.

[0041] The second layer, B2, has a ferroalloy matrix, which is preferably composed of the previously mentioned 316L or 430L material. The hard particles are preferably composed of an alloy of titanium carbide and iron-chromium (TiC-FeCr), or solely of titanium carbide or tungsten carbide.

[0042] Coating B is formed by the first and second layers B1 and B2, which is durable and resistant, and also produces less fine dust emissions during braking.

[0043] Furthermore, the positions of tool 13 at the beginning and end of the coating process opposite to the second layer B2 11a are shown in dashed lines (see 13' and 13''). It can be seen that tool 13 is positioned at the start of coating such that only about half of the outer diameter dL of the laser beam 14 and thus the laser spot generated by the laser beam extends radially outward beyond the inner diameter d1 of the brake disc 1. On the other side, tool 13 moves outward only to such an extent that only about half of the outer diameter dL of the laser beam 14 and thus the laser spot generated by the laser beam extends radially outward beyond the outer diameter d2 of the brake disc 1. In this way, the laser beam 14 and the supplied powder material p are limited from uncontrolled overspray reaching other parts outside the disc body 11. Overspray is understood as the area of ​​the brake disc 1 located radially adjacent to the coated surface (friction surface) where heated hard particles impact and adhere to or melt into the coating B, especially the second layer B2, during laser cladding. Such overspray must be removed in subsequent work.

[0044] By using a tool 13 that is radially offset inward relative to the edge of the disc-shaped body 11, i.e., relative to its inner diameter d1 and its outer diameter d2, the layer thickness of the applied layer B1 or B2 in the edge region of the disc-shaped body 11 is affected. In particular, this can result in the layer thickness of the applied layer B1 or B2 in these regions being lower than the layer thickness in the remaining regions of the disc-shaped body 11.

[0045] To overcome this problem, the following methods can now be adopted: Figure 3The method is shown in principle in the diagram. There, a diagram is shown above the brake disc 11, in which the trajectory offset sv of the diameter d of the disc-shaped body 11 of the brake disc 1 is plotted.

[0046] The chart shows that tool 13 (see...) Figure 2 The trajectory offset sv of the generated laser beam 14 varies along the radial path of the tool 13 on the disk-shaped body 11. At the beginning of coating (i.e., in the region of the inner diameter d1 of the disk-shaped body 11), the laser beam 14 and the powder material supplied thereto move radially across the disk-shaped body 11 with a small trajectory offset sv in the first stroke segment a, while the situation is different in stroke segment c. Stroke segment c accounts for the largest share of the laser beam 14's travel on the disk-shaped body 11. In stroke segment c, the trajectory offset sv of the laser beam 14 is the highest and constant. Finally, at the end of coating (i.e., in the region of the outer diameter d2 of the disk-shaped body 11), the trajectory offset sv again has a small trajectory offset sv in stroke segment e. The trajectory offset sv in stroke segment e is preferably equal to the trajectory offset sv in stroke segment a. In the stroke segments b and d located between them, the trajectory offset sv first continuously increases to the value of stroke segment c or the trajectory offset sv continuously decreases again to the value of stroke segment e, wherein the tool 13 stops after coating is completed.

[0047] By temporarily altering the trajectory offset sv during coating, particularly by using a lower trajectory offset sv at the beginning and end of coating, it is feasible to apply and melt more powder material p in the edge region of the disc-shaped body 11. This compensates for the situation where, to avoid overspray, the tool 13 does not begin and stop radially outside the disc-shaped body during its coating.

[0048] exist Figure 4 The text shows the relationship with... Figure 3 Similar illustrations to those in the text. However, with... Figure 3 The difference is that, instead of changing the trajectory offset sv of tool 13, the feed speed v of tool 13 is changed. This is achieved by adjusting the rotational speed n accordingly, at which the brake disc 1 rotates. This also improves the layer thickness in the edge region of the disc-shaped body 11.

[0049] exist Figure 5 Another implementation of the method can now be seen. (Based on...) Figure 2Unlike the previous illustration, here it can be seen that the tool 13 is positioned at the beginning of coating such that the outer diameter dL of the laser beam 14 and the laser spot generated by the laser beam are completely positioned above or on the disk-shaped body 11. At the end of coating, the tool 13 moves outward only to such an extent that the laser spot of the laser beam 14 still completely hits the disk-shaped body 11. Here, in both cases, the outer diameter dL of the laser beam 14 and the laser spot generated by the laser beam are exactly adjacent to the inner diameter d1 or the outer diameter d2 of the disk-shaped body 11. In this way, it is almost impossible for the laser beam 14 and the powder material p to reach other parts outside the disk-shaped body uncontrollably and cause overspray.

[0050] The tool 13, positioned above the disc-shaped body 11 at the beginning and end of the coating process, also affects the layer thickness of the applied layers B1 and B2 in the edge regions of the disc-shaped body 11. In particular, this may also cause the applied layers B1 and B2 to have a lower layer thickness in these regions than in the rest of the disc-shaped body 11.

[0051] To overcome this problem, the following approach can now be adopted: Figure 6 The method is shown in principle in the diagram. There, above the brake disc 11, a diagram is also shown in which the trajectory offset sv of the diameter d of the disc-shaped body 11 of the brake disc 1 is plotted.

[0052] However, with Figure 3 The difference is that only three travel segments a, c, and e exist. This is because tool 13 and therefore laser beam 14 do not have a trajectory offset sv at the beginning (travel segment a) and end (travel segment e) of the coating process. Therefore, tool 13 remains stationary and does not move during travel segments a and e. Thus, travel segments a and e should be referred to as time periods in this case, and mean that tool 13 is at the position shown by the dashed line (see...). Figure 5 There is no trajectory offset sv during the period when the brake disc 1 rotates at least one revolution.

[0053] Therefore, the trajectory offset sv is preferably set to zero during at least one revolution of the disk-shaped body 11 rotating at a rotational speed n. Since the laser beam 14 remains in its trajectory without radial offset during this revolution, more laser and powder material p can be brought onto the trajectory and melted while other process parameters (e.g., feed rate v and powder mass flow rate) remain constant.

[0054] During stroke segment c, the trajectory offset sv increases abruptly from zero to a set value, and the tool 13 performs linear motion with the laser beam 14 in the direction of the outer diameter d2 of the disk-shaped body 11. Once the laser beam 14 reaches the outer diameter d2 of the disk-shaped body 11 with its outer diameter dL, the trajectory offset sv drops sharply to zero again. However, the coating process preferably continues during the period when the disk-shaped body 11 rotates at least one revolution.

[0055] Particularly preferably, when the first layer B1 is applied, the trajectory offset sv is in the range of 0.30 mm / revolution to 0.45 mm / revolution in the second stroke segment c, and is particularly preferably about 0.37 mm / revolution; and when the second layer B2 is applied, the trajectory offset is in the range of 0.55 mm / revolution to 0.75 mm / revolution, and is particularly preferably about 0.64 mm / revolution. Here, the trajectory offset sv is set to zero during three revolutions in the first stroke segment a and in the third stroke segment e, respectively.

[0056] Unlike the illustrated embodiment (in which the coating B applied to the brake disc 1 consists of two layers (B1 and B2)), other numbers of layers are also conceivable. Thus, coating B may have only one layer. It is also conceivable that coating B may have more than two layers.

[0057] List of reference numerals 1 brake disc 10 matrix 11 disc-shaped body 11a side 11b edge face 12 groove-shaped recesses 13 tools 14 laser beams, laser spot a travel segment b travel segment e travel segment B coating B1 First Floor B2 Second Floor c travel segment d travel segment d1 inner diameter d2 outer diameter outer diameter of dL laser beam D Rotation axis e travel segment n rotation speed p powder materials sv trajectory offset v feed rate.

Claims

1. A method for coating a brake disc (1) made of gray cast iron or steel, wherein, The brake disc (1) has a base (10) and at least one disc-shaped body (11) extending radially from the base perpendicular to the rotation axis (D) of the brake disc (1). The disc-shaped body has a surface (11a) with a surface normal parallel to the rotation axis (D). A coating (B) is applied to the surface (11a) of the disc-shaped body (11) by laser cladding using a tool (13). The coating consists of at least one layer (B1, B2) applied to the surface (11a) of the disc-shaped body (11). During the application of the at least one layer (B1, B2), the tool (13) has a trajectory offset (sv) and a feed rate (v) relative to the disk-shaped body (11) for at least the main duration of the method, and wherein at least one laser beam (14) and powder material to be melted with a powder mass flow are supplied to the disk-shaped body (11) by the tool (13), characterized in that the trajectory offset (sv) of the tool (13) is temporarily changed during the application of the at least one layer (B1, B2).

2. The method according to claim 1, characterized in that, During the application of the at least one layer (B1, B2), the feed rate (v) and / or the powder mass flow are also changed.

3. The method according to any one of the preceding claims, characterized in that, After passing through the first radial travel segment (a, b) or after experiencing the first time period, the tool (13) moves with a constant trajectory offset (sv) of a specific value on the second radial travel segment (c) corresponding to most of the radial extension dimension of the disc-shaped body (11), and wherein a third radial travel segment (d, e) or a third time period is connected after the second radial travel segment (c), wherein the trajectory offset (sv) of the tool (13) during the first radial travel segment (a, b) or during the first time period and during the third radial travel segment (d, e) or during the third time period is lower than the value of the trajectory offset (sv) in the second radial travel segment (c).

4. The method according to any one of the preceding claims, characterized in that, The tool (13) has a constant feed rate (v) of a specific value on a second radial stroke segment (c) corresponding to most of the radial extension dimension of the disc-shaped body (11) after passing through a first radial stroke segment (a, b) or after experiencing a first time period, and wherein a third radial stroke segment (d, e) or a third time period is connected after the second radial stroke segment (c), wherein the feed rate (v) of the tool (13) is lower than the value of the feed rate (v) in the second radial stroke segment (c) during the first radial stroke segment (a, b) or during the first time period and during the third radial stroke segment (d, e) or during the third time period.

5. The method according to any one of the preceding claims, characterized in that, The tool (13) supplies a constant powder mass flow of a specific size to the disc body (11) on a second radial stroke segment (c) corresponding to most of the radial extension dimension of the disc body (11) after passing through a first radial stroke segment (a, b) or after experiencing a first time period, and wherein a third radial stroke segment (d, e) or a third time period is connected after the second radial stroke segment (c), wherein the supplied powder mass flow is higher than the value of the powder mass flow supplied in the second radial stroke segment during the first radial stroke segment (a, b) or during the first time period and during the third radial stroke segment (d, e) or during the third time period.

6. The method according to any one of the preceding claims, characterized in that, When applying the at least one layer (B1, B2), the tool (13) is positioned in the starting position and / or moves radially beyond the corresponding substrate to be coated to such an extent that at the end of coating, at most half of the laser spot generated by the laser beam (14) of the tool (13) extends radially beyond the inner or outer diameter (d1 or d2) of the disc-shaped body (11).

7. The method according to claim 6, characterized in that, When applying the at least one layer (B1, B2), the tool (13) is positioned in the starting position such that it moves radially beyond the corresponding substrate to be coated at the end of coating, such that the laser spot generated by the laser beam (14) of the tool (13) is radially within the disc-shaped body (11) and radially adjacent to the inner or outer diameter (d1 or d2) of the disc-shaped body (11) with its outer diameter (dL).

8. The method according to any one of the preceding claims, characterized in that, At the start or end of the application of at least one layer (B1, B2), the trajectory offset (sv) of the tool (13) is set to zero at least during one revolution of the disc-shaped body (11).

9. The method according to claim 8, characterized in that, At the start or end of the application of at least one layer (B1, B2), the trajectory offset (sv) of the tool (13) is set to zero during three, four or five rotations of the disc-shaped body (11).

10. The method according to any one of the preceding claims, characterized in that, A first layer (B1) and a second layer (B2) are applied to the surface (11a) of the disc-shaped body (11), wherein the trajectory offset (sv) is in the range of 0.30 mm / revolution to 0.45 mm / revolution when the first layer (B1) is applied and in the range of 0.55 mm / revolution to 0.75 mm / revolution when the second layer (B2) is applied during the second radial stroke segment (c).

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