Method for coating and cutting components - Patent Application 20070122997
Simultaneous coating and cutting on a hybrid machine tool addresses sequential process inefficiencies, improving production efficiency and accuracy by utilizing process heat for material softening and equal processing speeds.
Patent Information
- Application Number
- JP2025540522
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-12
- Filing Date
- 2024-01-09
- Publication Date
- 2026-01-23
AI Technical Summary
Existing methods for coating and machining components sequentially lead to significant cost, time, and technical disadvantages due to sequential process steps, clamping deviations, and residual stresses, resulting in shape and dimensional inaccuracies.
A method where coating and cutting processes are performed simultaneously or in parallel on a hybrid machine tool, utilizing process heat for material softening and reducing geometric deviations, with equal rotational speeds and feed rates to enhance machinability and dimensional stability.
Reduces production time, minimizes clamping deviations, and enhances dimensional accuracy and surface quality by integrating coating and cutting processes, allowing high-speed machining of difficult materials with reduced residual stresses and tool wear.
Smart Images
Figure 2026502530000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for processing a component, in which the component is coated by at least one coating process and the component and / or the coating applied to the component by the coating process is machined by at least one cutting process. The use of the proposed method is primarily located in the field of coating components.
[0002] After coating a substrate, for example to improve corrosion resistance or hardness, the surface quality required for functionality is often not yet achieved. Therefore, the coating process is followed by a finishing process, such as turning, grinding, or honing. The production of components using manufacturing technologies, such as coating and cutting, leads to significant cost and time disadvantages in addition to technical disadvantages due to the sequential sequence in the process chain. Furthermore, components are typically unclamped after each process step and machining and then re-clamped for the next machining step in the process chain. The additional clamping process causes deviations during clamping, which in turn leads to deviations in the shape and dimensional tolerances of the finished component. This deviation leads to different coating thicknesses across the component after the cutting process. The different material properties of the base material and the coating material cause residual stresses in the component, which can lead to component failure under continuous load.
[0003] Background technology Coating and grinding are usually carried out in several successive steps. For example, when coating brake discs in DE 102005008569 A1, irregularities in the coating surface are removed by subsequent surface grinding. In EP 2773881 A1, the brake discs are pre-processed by grinding before the coating process, which provides the surface required for high adhesion tensile strength.
[0004] The successive machining of workpieces is usually performed by transferring them to machines dedicated to the respective coating or cutting process. For example, a component may first be pre-machined on a turning center, then transferred to a coating machine, and after the coating process, re-fastened to the turning center for further machining. According to DIN 6386-2, the permissible concentricity tolerance TR for force-operated rotary chucks is 30 μm to 120 μm. Such deviations in concentricity are often a drawback for the coating process, as they require manual alignment of the workpiece after each re-machining step. Frequent re-machining reduces the productivity of the process chain.
[0005] An alternative to this is a hybrid machine tool, in which the workpiece remains clamped and the tool is changed between process steps. The hybrid design minimizes the changeover effort, since the workpiece only needs to be aligned once. EP 1 859 893 A describes a hybrid machine tool that allows automated changeover of a laser processing tool to a cutting tool.
[0006] The object of the present invention is to provide a method for processing components by coating and cutting, which allows for shorter production times.
[0007] Summary of the Invention This problem is solved by the method according to claim 1. Advantageous configurations of the method are the subject of the dependent claims or can be seen from the following description and examples.
[0008] In the proposed method, a component is coated by at least one coating process. Furthermore, the component and / or the coating applied to the component by the coating process is machined by at least one cutting process. The method is advantageous in that the cutting process and the coating process are carried out on the component at least temporarily simultaneously. That is, cutting and coating are at least temporarily parallel processes in terms of processing time, in which tools of both individual processes interact with the same component at least temporarily simultaneously.
[0009] In this case, the method can be used in various forms or for various applications. For example, a cutting process can smooth the surface of a coating applied to a component by a coating process. That is, in this case, the cutting process follows the coating process. There is also the possibility of processing the surface of the component by a cutting process before coating, in particular preparing it for coating. In this case, the coating process follows the cutting process. In the first case, the time interval between the coating process and the cutting process is preferably selected so short that the heat generated in the component and / or the applied layer by the coating process causes material softening for the subsequent cutting process, at least for some locations to be processed, preferably for each location to be processed of the component. This use of process heat for the subsequent cutting process allows for higher processing speeds, since this improves the machinability of stronger or more difficult-to-cut materials. In the second case, the cutting process preferably removes impurities from the surface of the component before coating and geometrically defines the surface. This reduces geometrically induced deviations in the coating process and increases the dimensional stability / final contour accuracy of the component.
[0010] In the proposed method, a multilayer coating may be applied by a coating process. It is also possible for the component to first be prepared for coating by a first cutting process, and then the coating is smoothed by a second cutting process. In this case, all three processes, i.e., the first cutting process, the coating process, and the second cutting process, may be temporarily performed on the component in parallel in terms of processing time.
[0011] In the proposed method, the component is preferably clamped in a chuck and rotated for the coating and cutting processes. Alternatively, the tool holder of the tool used for processing can rotate around the clamped component. Processing is accordingly carried out on a hybrid machine tool, which simultaneously offers both processing possibilities. In this case, coating and cutting are preferably carried out at equal rotational speeds. This rotational speed is preferably selected so that the surface speed of the component during parallel processing (relative to the tool holder) exceeds 1000 mm / min.
[0012] In principle, different feed rates can be selected for the cutting process and the coating process, but it is particularly advantageous to carry out both processes with equal feed rates, since this allows for a constant time offset between the two processes.
[0013] In the proposed method, the coating is preferably performed by a laser-based method, in particular by laser build-up welding. Extremely high-speed laser build-up welding (EHLA) is particularly advantageously used. In principle, other coating methods are of course also possible, such as thermal spraying. Metallic materials, ceramic materials, polymers, or metal-matrix composites can be used as coating materials. The coating is preferably applied to the component with a thickness of more than 10 μm.
[0014] The cutting process can be carried out by turning, grinding or honing, for example. Cutting can also be carried out by milling with a milling tool, in which case the coating speed of the coating process and the cutting speed of the cutting process are preferably selected to be equal to each other.
[0015] The proposed method offers cost advantages over techniques that use separate machines for coating and cutting. The investment in a second machine frame, a corresponding rotary unit, and corresponding control components is eliminated, since both machining processes can be performed on the same machine. At least temporarily, parallel processing in terms of processing time reduces the production time per component by eliminating processing steps. The method allows for the formation of coatings with high surface quality through simultaneous processing.
[0016] Machining with the same tension also reduces residual stresses caused by the cutting process and, therefore, the resulting distortion of the component due to the residual stresses. In the case of multilayer coating structures, pre-machining the component by intermittent cutting before material application reduces deviations due to the geometry in the coating process, thereby improving the dimensional stability or final contour accuracy of the component. Similar to laser-assisted turning or milling, cutting the coating immediately after the coating process allows the material to be processed within a temperature range where the tensile strength and thus the hardness of the material are sufficiently low. This achieves both economic and technical advantages. This method thus enables high-strength, difficult-to-cut materials to be machined at higher speeds with less wear on the cutting tool. Utilizing the process heat from the previous coating process further reduces porosity and microcracks in the edge zone, reduces residual stresses in the edge zone, and reduces the process forces that must be withstood by the machine tool during cutting.
[0017] The method is suitable for all applications where components are conventionally coated and machined sequentially. It can be used, for example, to produce corrosion- and wear-resistant coatings, adhesion and anti-adhesion coatings, electrical and thermal insulating coatings, coatings with hard and soft magnetic properties, as well as plain bearing coatings and functional surfaces. It can also be used to repair near-surface damage. The method is particularly suitable for applications where chemical and electrolytic processes, such as hard chromium plating, chemical and electrolytic nickel plating, and zinc plating, are conventionally used. Suitable coatings are required, for example, in the energy economy, automotive industry, transportation sector, metal and steel industry, food industry, plastics industry, chemical industry, paper industry, aviation and space industry, mining industry, or tool and equipment construction. Examples of applications include the production of wear-resistant coatings for calenders in plastic extrusion or for rolls in steel processing (e.g., cold rolling, hot rolling), corrosion-resistant coatings for rolls in papermaking, or brake disc coatings.
[0018] The proposed method will now be explained in more detail with reference to an embodiment and with reference to the drawings. [Brief explanation of the drawings]
[0019] [Figure 1] FIG. 1 shows the range for the coating or cutting speed and feed when machining a component by EHLA and turning for the example of the material WC-Co. [Figure 2] 1 is a schematic diagram of the proposed method configuration with components viewed from the side; FIG. [Figure 3] 3 is a schematic diagram of the arrangement of FIG. 2, with the components viewed in the axial direction.
[0020] MODE FOR CARRYING OUT THE INVENTION A method for coating a component (hereinafter also referred to as a workpiece) by laser build-up welding and smoothing the applied coating by turning is described again with reference to an example embodiment. For this purpose, a lathe is used that additionally includes a laser processing head suitable for laser build-up welding. For this purpose, the component is clamped in the lathe chuck and rotated during processing. It can be taken advantage of the fact that the rotational speeds and feed rates required for turning overlap with those required for coating by EHLA (Extreme High Speed Laser Build-up Welding), which is used in the illustrated example. This is shown diagrammatically in FIG. 1 for the application of the material WC-Co. As can be seen from the figure, the rotational speeds required for both processing methods on the lathe overlap within a range of approximately 20 to 100 m / min. The same applies to feed rates within a range of 0.1 to 0.3 mm / rev. Therefore, for processing the proposed method, rotational speeds and feed rates within this range are preferably used for this material. Similar situations apply for other materials.
[0021] FIG. 2 shows a side view of a workpiece being processed according to the proposed method, which is processed according to this example. In this case, the workpiece 1 is rotated accordingly, with the direction of rotation 3 indicated in the drawing. In this example, a coating is applied by a processing head 4 for laser build-up welding (EHLA in this case). An already partially applied coating 2 can be seen on the workpiece 1. In this case, the coating is smoothed by turning in parallel with the processing time, as shown in the drawing, using a turning tool 5. Each location of the just-coated workpiece 1 is already machined accordingly after half a rotation in this example. The relative movement 6 between the coating tool and / or cutting tool and the workpiece 1 is indicated by arrows.
[0022] For this purpose, the same process is shown again in Figure 3, but with the workpiece 1 viewed in the axial direction. By cutting immediately following the coating process, the process heat generated by the coating process is used to reduce the tensile strength and thus the hardness of the material for cutting. This allows for faster processing and reduces wear on the cutting tool. In the example shown, the coating is followed by cutting with a delay of half a revolution. However, this delay can be adjusted to be smaller or larger. [Explanation of symbols]
[0023] 1 Workpiece / component 2 Coating 3 Rotation direction 4 Processing head for laser cladding welding 5 Turning tools 6 Relative or feed motion
Claims
1. A method for processing a component, comprising coating the component (1) by at least one coating process and machining the component and / or a coating (2) applied to the component (1) by the coating process by at least one cutting process, The method, wherein the cutting process and the coating process are performed at least temporarily simultaneously.
2. 2. The method according to claim 1, characterized in that the cutting process smooths the surface of the coating (2) applied by the coating process.
3. 2. A method according to claim 1, characterized in that the surface of the component (1) is worked by the cutting process before being coated.
4. 3. The method of claim 2, wherein the time interval between the coating process and the cutting process is selected to be short enough that the heat generated by the coating process causes softening of the material deposited by the coating process for the subsequent cutting process.
5. 4. A method according to claim 3, characterized in that the surface of the component (1) is freed of impurities by the cutting process before the coating, and the surface is geometrically defined.
6. 6. The method according to claim 1, wherein the component (1) is clamped in a chuck during machining, and the component (1) or the tool holder is rotated around the component (1) for the coating process and the cutting process at a number of rotations selected identically for the coating process and the cutting process.
7. 7. A method according to claim 6, characterized in that the rotational speed is selected such that the surface speed of the component (1) relative to the tool holder during machining is greater than 1000 mm / min.
8. 8. The method according to claim 1, wherein the coating process and the cutting process are carried out with equal feed rates.
9. 9. The method according to claim 1, wherein the coating speed of the coating process and the cutting speed of the cutting process are selected to be equal to each other.
10. 10. The method according to claim 1, wherein the coating process is performed by a laser-based method, in particular by laser build-up welding.
11. 11. The method according to claim 1, wherein the coating process applies a coating (2) having a thickness of more than 10 μm to the component (1).
12. 12. The method according to any one of claims 1 to 11, characterized in that the component (1) is coated with a metallic material, a ceramic material, a polymer or a metal matrix composite.