EP3010682A1

EP3010682A1 - Method and system for preparing and coating a workpiece surface

Info

Publication number: EP3010682A1
Application number: EP14730877.9A
Authority: EP
Inventors: Hermann-Josef David
Original assignee: Duerr Ecoclean GmbH
Current assignee: Ecoclean GmbH
Priority date: 2013-06-17
Filing date: 2014-06-15
Publication date: 2016-04-27
Also published as: CN105307817A; US20160115578A1; WO2014202491A1; CN105307817B; DE102013211324A1

Abstract

The invention relates to a method for machining a surface (12) of a workpiece (16, 16`) and/or to a method for preparing a surface (12) of a workpiece (16) for the coating process, wherein a structure (15), in particular a macroscopic structure, for example a ridge and/or strip structure, is introduced into the surface (12) of the workpiece (16) using a tool. The surface (12) of the workpiece (16) is supplied with a fluid, in particular with a liquid, after the structure (15) has been introduced in order to produce structures (54). The invention further relates to a method for finishing the surface (12) of the workpiece (16), the surface (12) of the workpiece (16) being coated after the surface (12) has been prepared using such a method. The invention further relates to a system for preparing a surface (12) of a workpiece (16) for the coating process and for finishing the surface (12) of a workpiece (16).

Description

Method and installation for preparing and coating a workpiece surface

description

The invention relates to a method for processing a surface of a workpiece and / or for preparing a surface of a workpiece for coating, in which in the surface of the workpiece with a tool, in particular with a cutting tool, a structure, for. B. a (macroscopic) groove and / or strip structure is introduced. Moreover, the invention relates to a method for refining the surface of a workpiece, in which the surface of the workpiece is coated. In addition, the invention relates to a system for the preparation of a surface of a workpiece for coating and a system for coating a surface of a workpiece.

Surfaces exposed to high stress can be finished with coatings to protect them from damage or wear. To z. B. to refine the surfaces of cylinder bores in the cylinder crankcases of internal combustion engines, they can with different thermal spraying method, such. As LDS coating or plasma coatings are coated with a metallic alloy. In this way it is possible to improve the tribological properties of these surfaces and thus reduce the friction for the piston rings.

In the case of a mechanically stressed coating on a surface, the question of the adhesion of the coating to the surface is particularly acute.

In order to determine the adhesion properties of a surface of a workpiece made of a first material for a coating from a second, different In order to improve the material, it is known to introduce structures into the surface, with which the materials applied during a coating process can enter into a form-locking connection with the surface. In the surfaces of cylinder bores in cylinder crankcases are z. For this purpose, for example, groove-like structures or patterns are introduced by means of cutting tools (US Pat. No. 7,621,250 B2 and EP 1 759 132 B1).

In order to improve the adhesion properties of coatings on the surface of a workpiece, it is also known that surfaces with abrasives such. B. roughen sand or corundum. DE 10 201 1080 852 A1 describes applying a high-pressure water jet to the surface of workpieces in order to prepare them for coating.

The object of the invention is to provide a method for preparing a surface of a workpiece for coating and to provide a method for refining the surface of a workpiece, which substantially improves the adhesive properties of the surface of a workpiece and the adhesion of a coating applied to the surface to let.

This object is achieved by the method according to claim 1 and claim 13. Advantageous developments of these methods are specified in the dependent claims.

The invention proposes to prepare a surface of a workpiece for coating by introducing a (macroscopic) structure, in particular a groove structure, into the surface of the workpiece with a tool, and then thereafter with a fluid, in particular in the form of an incompressible material Liquid applied becomes. By such a loading with a fluid then the (macroscopic) structure can be superimposed on a microstructure.

A (macroscopic) structure can be introduced into the surface of the workpiece, in particular by means of fine spindles, i. H. be introduced in a machining mechanical machining method with a cutting tool in the form of a turning tool. In principle, however, the structure can also be replaced with another tool, e.g. with a milling tool, a laser or a spark erosion device. The structure is embodied, for example, in the form of a (in particular macroscopic) recess structure in the surface. In this case, a surface may be provided with a plurality of grooves, wherein one or more grooves may have, for example, a groove profile with at least one undercut. In special embodiments, groove profiles are provided with partly rounded or partly rectangular elevations and / or depressions. Optionally, two undercuts are preferably provided in the region of a recess of a groove, so that, for example, a dovetail-shaped groove profile can result. The grooves of a macroscopic structure according to the invention (for example a depression structure) are preferably between 10 μm and 500 μm deep and between 30 μm and 500 μm, in particular between 50 μm and 100 μm wide. The grooves in the surface of a workpiece can, for. B. have a distance from each other, which is between 30 μιτι and 500 μιτι so that there is a flat back or web section (survey) between the grooves. The structure introduced into the surface of the workpiece can be both regular and irregular. The structure may also comprise a plurality of strips, which are preferably designed as round bars.

In order, for example, to achieve a uniform adhesion of a coating to the surface of a workpiece, a uniformly distributed surface roughness is sought in the region of a (macroscopic) structure according to the invention. Subareas with insufficient structuring of the Surface could lead to later release of the coating. For other reasons, evenly distributed surface roughness and / or uniform surface structuring on workpieces are advantageous, for example to avoid corrosion, for optical reasons, etc.

The inventor has recognized that with machining, mechanical machining processes in which the surface of a corresponding workpiece is processed with a cutting tool, a structuring of the surface of a workpiece in a required groove depth and quality in certain applications not or only with great effort in can be guaranteed process reliable industrial mass production. One reason for this is that with a rotating cutting tool in the surface of a bore, for. B. a cylinder bore generated groove or groove has a dependent on the roundness of this hole depth. In fact, it has been found in practice that the roundness of cylinder bores in industrially manufactured engine blocks is subject to certain fluctuations. This has the consequence that a cutting tool rotating about an axis has a reduced immersion depth in the workpiece material in the case of surfaces which rest against a standard dimension, which leads to a lower structural depth.

Further fields of application for the methods according to the invention are surfaces on a workpiece which are not optimally accessible for a cutting tool or another tool for machining because of the geometry of the surface. For example, a structuring of the surface of a workpiece in a required groove depth and quality in an industrial Mass production reliably ensured only with great effort, if the surface to be structured is small relative to the tool and / or positioned in a recess. In certain areas of workpieces such. B. engine blocks is the introduction of structures in the surface of the workpiece with a rotating mechanical cutting tool not at all or only with great effort possible. This applies, for example, to cast cylindrical bores for supporting a crankshaft, pulsating bores and chamfers in cylinder bores, as well as for overhangs or undercuts with a larger diameter (honing clearance).

In particular, the inventor has recognized that the adhesive properties of the surface for a coating and the adhesion of a coating applied to the surface, but also other qualitative properties of a surface can be improved if the surface provided with a (macroscopic) structure has a surface Workpiece an additional microstructure is introduced. It is inventively provided to produce the (macroscopic) structure, in particular with a machined, mechanical roughening or machining process and then post-treated with a fluid. Thus, certain (macroscopic) structures, such as groove-shaped structures in the cylinder bore of an engine block, which are produced with a rotating cutting tool in the surface of a workpiece, can advantageously be improved by superposition with a microstructure, wherein the microstructure with the aid of an abrasive effect Fluids should be generated. The fluid is able to reach surfaces that can not be reached with another tool. In particular, web sections lying between two (macroscopic) grooves, in which the surface can have remained unprocessed in the first method step, can be additionally structured. This leads on the one hand to a general improvement of the surface quality, but in particular also to the fact that a coating applied to such a surface can cling particularly well to this surface. Also, other surface features such as the hardness of the surface can be changed. Thus, a microstructure is preferably introduced into the (macroscopic) structure in that a fluid is sprayed onto the surface of the workpiece in the form of a fluid jet through one or more openings of a nozzle tool. leads. In a particularly preferred embodiment, the nozzle tool has a nozzle chamber in which the fluid or the liquid is subjected to a pressure which is greater than 100 bar, preferably greater than 150 bar, particularly preferably greater than 300 bar, and which in particular especially between 2000 bar and 4000 bar and z. B. 3000 bar. In a specific embodiment, the nozzle tool and / or the workpiece are moved relative to one another during the application of the workpiece in a specific path, said path being selected at a non-zero angle relative to a plurality of grooves of the (macroscopic) structure. In a further specific embodiment, the fluid jet is applied to the surface of the workpiece with temporally changing pressure.

According to the invention, the provided microstructures may have, for example, a conical, (semi) spherical, trough-shaped or grooved basic shape. The microstructures have in a preferred embodiment, at least in sections, a circular contour with a diameter which is preferably between 1 μιτι to 50 μιτι. The microstructures may, for. B. 1 μιτι to 50 μιτι deep. The microstructure introduced into the surface by means of the fluid jet is a substructure with respect to the structure in the surface. That is to say, the dimensions of the microstructure introduced into the surface by means of the at least one fluid jet are significantly smaller than the dimensions of the macroscopic structure in the surface prior to the application of the fluid.

The inventor has found that the erosion effect of a fluid jet impinging on the surface of a workpiece is increased from a fluid or a liquid if there are structures in the form of depressions in the surface which are deep between and between μιτι and μιτι 30 μιτι and 500 μιτι wide, in particular between 50 μιτι and 100 μιτι are wide. Extensive tests have shown that due to such depressions in the surface of a workpiece and the Pulse can be transmitted from so-called Querjets on the workpiece, ie the pulse of fluid jets, which extend transversely to the surface normal of the workpiece surface. According to the invention, the roughness of the patterned surface of a workpiece is increased by the application of the fluid or liquid.

Here, the roughness of the surface is understood to mean the arithmetic mean of the average distance of a set of measuring points arranged on the surface from a center line or central surface on which the sum of the deviations from the surface is minimal for the measuring points. By increasing the roughness of the surface of a workpiece by the impingement of the fluid, the surface of the workpiece can be increased, so that in total the adhesion forces with which a coating applied to the surface of the workpiece is increased on the workpiece Surface is held.

By subjecting the surface of the workpiece to a liquid, it can also be achieved that this surface is cleaned of contamination with cooling lubricants and chips, which may have been left behind during a mechanical, in particular machining, machining in a previous working step.

In particular, the inventor has found that to carry out the method according to the invention, a fluid in the form of a liquid of water and / or a mixture of water and detergent, such as a wash liquor and / or a mixture of water and biocide and / or corrosion inhibitors and / or from a water-oil emulsion and / or oil particularly well. By applying an upper Surface of a workpiece with a (high-pressure) fluid jet of this liquid can be produced in the surface of the workpiece according to the invention microstructures that allow a firm connection of the workpiece and coating and thus support the adhesion of a coating on this surface.

In order to facilitate the production of microstructures in the surface of a workpiece provided with a (macroscopic) structure, the fluid or liquid may be mixed with chemical and / or abrasive components. In a preferred embodiment of the invention, the fluid used is compressed air which contains sand grains, plastic particles, glass particles, corundum, water ice and / or CO2 E1S as additional abrasive constituents. A realization of the invention is also that, if the at least one fluid jet for impinging the surface of a workpiece has a beam angle which is between 10 ° and 60 ° and which is preferably 20 °, the desired microstructures in the surface of the workpiece, in particular the flanks of macroscopic grooves or depressions can be formed, which further improves the adhesion of a coating applied to the surface of the workpiece. A good erosion effect can be achieved, in particular, if the fluid jet has a jet direction which strikes the surface with an incident angle β at 70 ° <β <90 ° which is related to the surface at a local tangential plane. A particularly good erosion effect of the fluid jet can be achieved if the fluid jet is generated with a flat jet nozzle or a hollow cone jet nozzle. A fan jet nozzle allows the provision of a fan-shaped, flat fluid jet. With a hollow cone jet nozzle, it is possible to generate a fluid jet in the geometry of the lateral surface of a hollow cone. However, the fluid jet can also be generated with a full jet nozzle. An idea of the invention is also to act on the surface of a workpiece simultaneously or successively with a fluid jet, which is guided at different beam angles α and / or different angles of incidence β on the surface of the workpiece.

In this case, the angle of jet spanned by the fluid jet is understood as the nozzle tool after it has emerged from the opening of a nozzle. The angle of incidence β is the angle between the mean beam direction and the perpendicular perpendicular of the mean beam direction to the local tangential plane to the surface in the point of impingement of the fluid jet in which the mean beam direction intersects the surface. Moreover, it is an idea of the invention to set one or more operating parameters for the nozzle tool, and thus in particular the nature of the at least one fluid jet for the application of the surface of the workpiece as a function of the intrinsic and / or extrinsic nature of this surface. Under the intrinsic nature of the surface here the material and the material structure, the structure of the surface, and the grain structure of the material of the surface, the hardness and roughness of the surface of the workpiece understood, as well as a concentration of air bubbles or voids in Area of the surface of the workpiece. The extrinsic nature of the surface of the workpiece is understood to mean the local geometry of the surface, such as surface curvatures, undercuts, protruding and recessed structures, as is the case, for example, with a mocking clearance for a cylinder bore in an engine block. The set nozzle tool operating parameters may be, for example, a fluid pressure of the fluid medium in the nozzle chamber and / or a feed rate of the nozzle tool relative to the workpiece in FIG the direction of a spindle axis, a rotational speed of the nozzle tool about the spindle axis, a pulse frequency of the liquid jet, a pulse duration of the liquid jet, an amplitude and / or power of an ultrasonic generator for generating a pulsed fluid jet. The nature of the at least one fluid jet may be, for example, the velocity and consistency of the fluid emerging from a nozzle orifice in the nozzle tool.

In particular, it is an idea of the invention to adjust the nature of the at least one fluid jet for the application of the surface of the workpiece as a function of the local intrinsic and / or extrinsic nature of this surface.

The local intrinsic and extrinsic nature of the surface of the workpiece may be e.g. be known and stored in a data store. However, it is also possible to determine the nature of the surface of the workpiece before or after, possibly also during the application of a fluid jet in a (preferably non-destructive) measuring process, for. B. by measuring in a Tastschnittverfahren in which a probe tip preferably moves from diamond at a constant speed over the surface and their positional shift then with a z. B. inductive displacement measuring system is detected. The nature of the surface of the workpiece can also be determined by measuring with a confocal measuring system, as z. As described in the publication by M. Weber and J. Valentin, QZ Quality and Reliability 5, 51 (2006), incorporated herein by reference in its entirety, the disclosure of which is incorporated into the description of the present invention, or by surveying the surface of the workpiece with a microscope, z. B. a scanning electron microscope.

By one or more nozzle tool operating parameters depending on the location of the surface acted upon by at least one fluid jet, the orientation of the fluid jet with respect to the surface and / or the extrinsic and / or intrinsic nature of the surface and / or the relevant structural features of the surface of the workpiece or a like workpiece measured for the adhesion of a coated coating, the surface thereof for coating has already been prepared, or the stored in a data storage, for the adhesion of a coated coating relevant structural features of the surface can be adjusted, it can be achieved that a lack or insufficient structuring of the surface of a workpiece can be compensated. After such compensation, despite local differences in geometry, shape, and / or depth of a structure created on the surface of a workpiece, a coating may be applied to the patterned surface of the workpiece, with the coating adhering particularly well. In particular, this achieves uniform adhesion of the coating on the surface of the workpiece.

In order to avoid that a thermal coating of the surface of the workpiece is affected by liquid residues, it is advantageous if the surface is treated with blast air before coating and / or z. B. is dried by vacuum drying.

A surface of a workpiece prepared for coating according to the invention is particularly suitable for thermal coating, for example for coating with a thermal spraying method, such as LDS coating or plasma coating or arc wire spraying or flame spraying.

According to the invention can be refined in this way, the surface or the wall of a cylinder bore in an engine block or in a cylinder housing or in a crankcase by coating. The preparation of the surface of a workpiece for coating is preferably carried out in several successive steps. In a first step, the surface of the workpiece is mechanically structured in the areas that can be reached with a cutting tool. In a second step following the first step, the surface of the workpiece is then subjected to a high-pressure fluid jet of a fluid, in particular a liquid, in order in this way to produce microstructures in the surface of the workpiece. In an optional third step following the second step, the surface of the workpiece is rinsed with liquid or gaseous fluid. In a further optional step, the workpiece in a subsequent process step z. B. aftertreated with blown air and / or freed of liquid residues in a vacuum dryer. It is also an idea of the invention to provide a machining method for a plurality of workpieces in a preferably industrial process in which (macroscopic) structures are produced in the surface of a work piece after a machining or roughening process. to carry out an automated, preferably non-contact measurement of the topography and / or the structural features of a workpiece surface that are relevant for the adhesion of a coated coating. In this case, a workpiece surface is measured, for example in a Tastschnittverfahren to then set in an automated control loop one or more parameters for the introduction of microstructures by means of a fluid jet. In a modified machining method for a plurality of workpieces, following a roughening process in which microstructures are produced in the surface of a workpiece, a measurement of the topography and / or the structural features of a workpiece surface that are relevant for the adhesion of a applied coating is undertaken. In this case, a workpiece surface is measured in order to then set in a control loop one or more parameters for the introduction of microstructures by means of a fluid jet. As an alternative or in addition to the measurement of the surface in a stylus method, the surface can be measured for this purpose, for example, with a confocal measuring system or with a microscope or electron microscope.

In the context of an industrial process in which a plurality of similar workpieces are treated in succession for introducing microstructures according to the invention, an adjustment of the parameters for the introduction of. Can be based on the measurement of a first workpiece or on the measurement results obtained on the first workpiece Microstructures are made by means of a fluid jet to other workpieces. A repeated adjustment of said parameters then results according to the invention an optimization in the adjustment of the fluid jet for the introduction of microstructures. Particularly preferably, the fluid jet is continuously optimized via one or more parameters, the introduction of microstructures into the surface of the measured or at least one subsequent workpiece depending on the measured values for the topography or the structural features of the surface relevant for the adhesion of a coating applied. can be optimized.

The processing method according to the invention for a plurality of workpieces in a preferably industrial process makes it possible to shorten process times, to qualitatively improve mechanically machined surfaces of a workpiece, to optimize the adhesion values of coatings and, moreover, to the surface of a workpiece clean.

The invention also extends to an apparatus for preparing a surface of a workpiece for coating and / or refining the surface of a workpiece by means of coating. In a plant according to the invention, a fluid or a liquid is on the surface of the Workpiece preferably with a nozzle tool can be fed, which has a rotatable about a spindle axis and displaceable in the direction of the spindle axis nozzle body with a nozzle chamber and at least one nozzle opening for providing at least one continuous or pulsed fluid jet. It is advantageous if the nozzle tool is assigned a control and / or regulating device for adjusting at least one nozzle tool operating parameter, eg a nozzle tool operating parameter from the group fluid pressure / fluid pressure in the nozzle chamber, feed rate relative to the workpiece in the direction of Spindle axis, rotational speed about the spindle axis, pulse frequency of the fluid jet / liquid jet, pulse duration of the fluid jet / liquid jet, amplitude and / or power of an ultrasonic generator for generating a pulsed fluid jet. This control and regulating device serves to set the at least one nozzle tool operating parameter depending on the location of the surface and / or the geometry of the surface and / or the intrinsic or extrinsic nature of the surface. This setting can be done in particular on the basis of measurement data recorded on a workpiece other than the one currently being machined in the plant, eg. B. on an already machined in the plant workpiece, ie a workpiece in which the processing is completed in the system.

In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing.

Show it:

Fig. 1 shows a plant with a device for preparing a surface of a workpiece for coating;

Fig. 2 is a moving in a cylinder bore nozzle tool of the system; FIG. 3 shows an angle of incidence for a fluid jet issuing from a nozzle of the nozzle tool onto the surface of a workpiece; FIG.

4 is an enlarged view of a cross-sectional profile of a surface of a workpiece having a groove-like structure;

5 shows an enlarged view of a cross-sectional profile of a microstructured surface of the workpiece after applying a high-pressure fluid jet from a liquid;

6 shows an enlarged plan view of a microstructured surface of the workpiece after being exposed to a high-pressure fluid jet from a liquid;

Fig. 7 is a cross-sectional profile of a surface of a workpiece having a groove-like structure having undercuts;

8 shows a cross-sectional profile of a surface of a workpiece with a

Around groove structure; and

9 is a cross-sectional profile of a surface of a workpiece with a

Around strips structure.

The embodiments of the invention outlined in detail below generally relate to methods for surface treatment on, in particular, metallic components. For example, highly stressed parts of internal combustion engines, in particular cylinder liners in reciprocating piston engines, can be used as components. surface (in particular with regard to roughness, dimensional accuracy and hardness).

The abovementioned components are generally produced in a plurality of operations, wherein a workpiece in the form of a blank is first created from a metallic semi-finished product by forging, casting or other methods. Such a blank is used as a workpiece for the processing steps described below and thus as the starting material for the inventive method.

In a first step according to the invention for treating the surface of such workpieces, it is proposed to provide a surface of the workpiece with a (macroscopic) structure by means of machining processes. For example, according to the invention, a groove structure is to be introduced into a cast cylinder bushing of an engine block (blank, workpiece). In this case, techniques known in the art such as turning, fine spindles, honing etc. are used. In modified embodiments and in other applications, said structure can also be replaced with another tool, e.g. with a milling tool, a laser or a spark erosion device to produce a metallic workpiece.

The structure is embodied, for example, in the form of a macroscopic depression structure in the surface. In this case, a surface with a plurality of grooves (comprising alternating elongated elevations and depressions) may be provided. In special embodiments, groove profiles are provided with partly rounded or partly rectangular elevations and / or depressions. The grooves of a structure according to the invention (for example a depression structure) are preferably between 10 m and 500 μm deep and between 30 μm and 500 μm wide. The grooves in the surface of a workpiece preferably have a distance from each other, which is between 30 μιτι and 500 μιτι, so that between the grooves a flat back or web section (collection) of appropriate width is generated. The introduced into the surface of the workpiece structure can be both regular and irregular. The structure may also comprise a plurality of strips, which are preferably formed as round bars. In a preferred embodiment, the workpiece has a structure with a plurality of grooves or strips of uniform orientation.

Due to a possible inaccurate shape of the blank (especially in mass produced in industrial mass production), it is possible that after the introduction of the structure in the first step, the wells have a non-uniform, changing along the surface depth. That is, the target depth can vary, for example, by 10 m to 100 μιτι at the same time, the surface roughness may vary by 10% to 50%.

Such a machined workpiece may now be a workpiece 16 'designed as a motor block 16. The engine block 16 has, in particular, a plurality of cylinder bores 14 which, according to the first method step shown above, have a surface 12 with a structure 15 in the form of grooves. Such an engine block 16 may e.g. consist of an aluminum alloy. According to the invention, this is transferred from a system for carrying out the first method step to a system 10 described in more detail below, in which further method steps of the method according to the invention are carried out.

The plant 10 shown in FIG. 1 is designed for machining a surface 12 of a cylinder bore 14 in the formed as a motor block 16 workpiece by the surface 12 is acted upon by means of pulsating fluid jets 18 of water. The water of the fluid jets 18 may contain detergent, biocide and corrosion inhibitor and may also be mixed with chemical and / or abrasive components. For generating the fluid jets 18 from water, the system 10 has a pumping device 20 and a cannister 22 with a device 24 for generating fluid pressure waves. The device 24 is connected to a controllable frequency generator. The device 24 contains a piezoelectric crystal, which acts as an electromechanical transducer and is connected to a sonotrode. When the chamber 22 is filled with water, the sonotrode in the water pressure waves with a frequency v can be generated, which is preferably in the range 10 kHz <v <50 kHz.

For generating pressure waves, the piezoelectric crystal is subjected to a high-frequency alternating voltage from a frequency generator. The frequency generator is designed for generating ultrasonic frequencies, preferably ultrasonic frequencies in the range 10 kHz <v <50 kHz. By adjusting the frequency v and the amplitude A _{P of} the AC voltage generated by the frequency generator, the wavelength λ and the amplitude of the pressure waves in the line 26 can be varied.

The conduit 26 connects the chamber 22 to a nozzle tool 28 having a nozzle chamber and containing a plurality of nozzles 30. In principle, however, the nozzle tool 28 can also be designed as a nozzle tool which has only one nozzle. The pressure acting on the liquid in the nozzle chamber pressure is z. B. 600 bar or very much more, z. B. 3000 bar. The conduit 26 has a chamber side portion and includes a nozzle side portion. The chamber-side portion and the nozzle-side portion are connected by means of a pivot joint 32. In the rotary joint 32, the nozzle-side section can be moved in an oscillating and / or rotating manner by means of a motorized rotary drive about a spindle axis 34 coaxial with the line 26.

The workpiece 16 'is connected to a z. B. trained as a robot manipulator 36, where it in the marked with the double arrow 38 made direction can be shifted. In this way it is possible to move the nozzle tool 28 and the workpiece 16 'relative to each other and to impinge the surface 12 with pulsating high-pressure fluid jets from the nozzle tool 28.

It should be noted that in an alternative embodiment of the system 10 it can also be provided that the workpiece 16 'is arranged immovably and the nozzle tool 28 received on the line 26 is moved by means of a manipulator 36 in the direction of the double arrow 38 with respect to the workpiece 16' becomes. In a particularly preferred embodiment, the workpiece and the nozzle tool are in any case moved relative to one another in such a way that the nozzle tool is moved at a non-zero angle relative to a groove structure present in the workpiece. This allows the nozzle tool to produce elongate microstructures that intersect the macroscopic structure.

The system 10 comprises a control computer 39 with a data memory. The control computer 39 is connected to the pumping device 20, to the device 24 for generating fluid pressure waves, to the motorized rotary drive in the rotary joint 32 and also to the manipulator 36.

The system 10 includes a measuring device 40 with a confocal microscope 42 for measuring the surface 12 of a cylinder bore 14 after machining with the nozzle train 28. The confocal microscope 42 is received on a holding device 44 and can thus be in a cylinder bore 14 of the engine block 16th introduce. The confocal microscope 42 can be rotated about the axis 45 of a cylinder bore 14 and includes an image sensor for detecting a confocal image of spots on the surface 12 of a cylinder bore 14.

With the measuring device 40 it is possible to determine the topography and the properties relevant to the adhesion of a coated coating Surface 12 in a cylinder bore 14 to detect spatially resolved. The measuring device 40 is connected to the control computer 39, which, due to the surface topography of the cylinder bore 14 detected by the measuring device 40 for processing with the nozzle tool 28, has one or more operating parameters for the nozzle tool 28 for machining a further cylinder bore 14 of the same engine block 16 o - that of another engine block 16 controls, for example, the fluid pressure in the nozzle chamber, the feed rate of the relative displacement of nozzle tool 28 and motor block 16 in the direction of the spindle axis 34, the rotational speed about the spindle axis 34, the pulse frequency of a fluid jet, the pulse duration of a fluid jet the nozzles 30, the amplitude and / or power of the acting as an ultrasonic generator frequency generator for generating pulsed fluid jets. According to the invention, therefore, the workpiece (embodied here as an engine block) in the method steps described above can be produced from a lightweight, comparatively soft and / or cost-effective material such as, for example, an aluminum or magnesium alloy and inexpensively machined. In this case, the method according to the invention preferably serves not only to provide a high-quality surface with a uniform structure and roughness, but in particular can also serve to provide a surface prepared for subsequent coating with a material different from the material of the blank.

In order to improve the tribological properties and to allow for an engine block made of an aluminum alloy despite the high temperatures and pressures in the combustion processes in an internal combustion engine, the cylinder bores in an engine block according to the invention in a thermal spraying process with a metallic Alloy coated. By coating the cylinder bores, the weight of the To reduce the door block by a lighter material is selected as the base material for the blank. Thus, compact designs are possible, such as cylinder crankcases, in which the cylinder bores compared to conventional housings have a reduced distance from each other.

Such a metallic alloy of the coating differs significantly from the base material of the engine block by one or more alloy components. For example, the material of the coating z. Example, have a carbon content of 0.8 to 0.9 weight percent and in particular contain dispersed friction-reducing fillers in the form of graphite, molybdenum sulfide and tungsten sulfide.

FIG. 2 shows a partial section of the engine block 16 from FIG. 1 with the nozzle tool 28. The cylinder bore 14 is widened on the side of the crankshaft drive 46 and has a honing release 48 with a shoulder 50 and a pulsation bore 52 which provides pressure compensation between enables the different cylinder bores 14 in the engine block 16.

By subjecting the surface 12 of the cylinder bore 14 to simultaneous displacement of the nozzle tool 28 relative to the engine block 16, the surface 12 can be roughened in a defined manner in its different regions.

With the nozzle tool 28, it is possible to roughen areas of the surface 12 of the cylinder bore, ie in particular to provide microstructures in which structuring of the surface with a mechanical cutting tool or laser machining can not be effected because these areas, such as a pulsation bore 52, due to their local geometry for a cutting or laser tool are not or very difficult to access. A shown in Fig. 2 fluid jet 56 from the nozzle tool 28 has a beam angle a, which is between 10 ° and 60 ° and which is preferably 20 °. The jet angle α is the angle spanned by the fluid jet 56 after emerging from the opening of the nozzle 30 of the nozzle tool 28. In this way it can be achieved that the flanks 58 of grooves in the surface of a workpiece are roughened with the fluid jet can and can be created by applying a fluid jet at these locations also microstructures. In a modified embodiment of the plant, the nozzle tool 28 has a plurality of nozzle openings from which a high-pressure fluid jet with a different jet angle α can emerge.

FIG. 3 shows the impact angle β on the surface 12 for the fluid jet 56 emerging from the nozzle tool 28. This angle of incidence β is related to the mean beam direction 57. It corresponds to the angle β between the mean beam direction 57 and the vertical perpendicular 61 of the mean beam direction 57 to the local tangential plane 59 to the surface 12 in the impact point 63, in which the mean beam direction 57 intersects the surface 12. One finding of the invention is that microstructures can be generated in the surface 12 particularly efficiently if the following applies for the above-mentioned angle of incidence β: 70 ° <β <90 °.

The contamination in the form of cooling lubricants and chips generated by machining on a surface is removed. As a result, it is no longer absolutely necessary to clean the surface before applying the coating in a separate cleaning step. In order to free a workpiece from liquid residues before coating, this is treated with blowing air and then dried, for example, in a vacuum dryer. 4 is an enlarged view of a cross-sectional profile of the surface of a workpiece having a structure formed as a groove structure with a plurality of grooves 60. The grooves 60 are a recess structure in the surface 12 of the workpiece. You are here about 50 μιτι deep and about 100 m wide. The distance between two grooves 60, ie the width of the back between the here is about 100 μιτι.

The surface 12 has a roughness related to the centerline 64 having a roughness value Rz which is increased by the impingement of the surface 12 with the high pressure fluid jet by at least about 20%.

FIG. 5 shows, in an enlarged view, the correspondingly roughened surface with microstructures 54 after application of the high-pressure fluid jet from the nozzle tool 28 in the installation 10. For the roughness value Rz ^' relating to the center line 64 ^' : Rz ^' > 1, 2 χ Rz.

FIG. 6 shows an enlarged plan view of the microstructured surface 12 of the workpiece after applying a high pressure fluid jet from a liquid. In the ridge or back sections, flanks and valleys of the groove structure, there are uniformly distributed microstructures 54 which increase the roughness of the surface 12, ie, for example, a roughness value Rz = 50 μιτι of the surface 12 provided with the groove structure before being applied increase with the high-pressure fluid jet to a roughness value Rz ^' = 60 μιτι after applying the high-pressure fluid jet.

FIG. 7 is a sectional view of another workpiece 16 'having a surface 12' with a groove-like structure in the form of dovetail-shaped grooves 60 'with undercuts.

FIG. 8 shows a sectional view of a workpiece 16 "having a surface 12" in which a structure having a multiplicity of side by side 9 shows a workpiece 16 "'having a surface 12"' with a structure in the form of many adjacent round bars 62. It should be noted that the control computer 39 in a modified embodiment of the plant 10 may also include a computer program with a control loop, by means of which one or more operating parameters for the nozzle tool 28 for processing the surface 12 of a cylinder bore 14 in dependence on the detected with the measuring device 40 local topographic or applied for the adhesion of a Be In addition, it should be noted that the measuring device 40 can basically also be designed as a device for measuring the surface 12 of a cylinder bore 14 with the stylus method. Except It is also possible to measure the surface of workpieces with an electron microscope in order to determine the topography of the surface and its properties relevant for the adhesion of a coating applied. Finally, it should be noted that the system 10 can also be designed for applying workpieces with continuous, non-pulsating fluid jets. For the production of microstructures 54 in the surface 12 of a workpiece, the system 10 z. B. be operated with a liquid consisting of water and / or a mixture of water and detergent, for. As washing liquor and / or consists of a mixture of water and biocide and / or corrosion inhibitor and / or from a water-oil emulsion and / or oil. It is also possible to add to this liquid chemical and / or abrasive constituents in order to remove the material of a workpiece removing effect of a high-pressure fluid jet from this liquid. increase their speed. With the system 10 shown in Fig. 1, of course, fluid jets can be provided for applying the surface of workpieces that do not pulse. With a pulsating fluid jet emerging from the nozzle tool 28, however, a greater abrasive action can be achieved at the same pressure in the nozzle chamber than with a non-pulsating fluid jet.

In particular, the following preferred features of the invention are to be stated: The invention relates to a method for machining a surface 12 of a workpiece 16, 16 ', 16 ^" , 16 ^'" and / or a method for preparing a surface 12 of a workpiece 16, 16 '. 16 ^" , 16 ^'" for the coating, in which in the surface 12 of the workpiece 16, 16', 16 ^" , 16 ^"' with a tool, a structure 15, in particular a macroscopic structure, such as a grooved and / or strip structure - is brought. After the introduction of the structure 15 for the production of microstructures 54, the surface of the workpiece is subjected to a fluid, in particular a liquid. Moreover, the invention relates to a method of refining the surface 12 of a workpiece 16, 16 ', 16 ^" , 16 ^'" in which the surface 12 of the workpiece 16, 16 ', 16 ^" , 16 ^{"' is} coated after the surface 12 was prepared with such a procedure. In addition, the invention relates to a system for preparing a surface 12 of a workpiece 16, 16 ', 16 ^" , 16 ^'" for coating a device and for refining the surface 12 of a workpiece 16, 16 ', 16 ^" , 16 ^"

LIST OF REFERENCE NUMBERS

10 plant

12, 12 ',

12 ", 12" 'surface

14 cylinder bore

15 structure

16 engine block

16 'workpiece

16 ", 16" 'workpiece

18 fluid jet

20 pumping device

22 chamber

24 Device for generating fluid pressure waves 26 line

28 nozzle tool

30 nozzle, nozzle opening

32 swivel joint

34 spindle axis

36 manipulator

38 double-headed arrow

39 control computer, control and / or regulating device

40 measuring device

42 microscope

44 holding device

45 axis

54 microstructures

56 fluid jet

57 beam direction

58 flanks

59 Tangential plane

60, 60 'grooves "Rundrillen Lot

round bars

of impact

center line

Claims

claims

1 . Method for processing a surface (12) of a workpiece (16, 16 ') and / or for preparing a surface (12) of a workpiece (16, 16') for coating, in which the surface (12) of the workpiece (16 , 16 ') with a tool a structure (15), in particular a macroscopic structure, for. B. a grooved and / or strip structure is introduced, characterized in that the surface (12) of the workpiece (16, 16 ') after the introduction of the structure (15) for the production of microstructures (54) with a fluid, in particular is acted upon with a liquid.

2. The method according to claim 1, characterized in that the roughness of the surface (12) is increased by the application of a fluid or a liquid at least in sections. 3. The method of claim 1 or 2, characterized in that the fluid as at least one pulsating or continuous fluid jet (56) on the surface (12) of the workpiece (16, 16 ') is guided, wherein the fluid jet (56) is produced with one or more nozzles (30) of a nozzle tool (28), wherein the nozzle tool (28) in particular a nozzle chamber, in which the fluid or the liquid is in particular subjected to a pressure which is greater than 100 bar, preferably greater than 150 bar, more preferably greater than 300 bar, and in particular between 2000 bar and 4000 bar and z. B. 3000 bar.

4. The method according to any one of claims 1 to 3, characterized in that as fluid a liquid of water and / or from a mi from water and cleaning agents, eg. As washing liquor and / or from a mixture of water and biocide and / or corrosion inhibitor and / or from a water-oil emulsion and / or selected from oil.

Method according to one of claims 1 to 4, characterized in that the fluid is mixed with chemical and / or abrasive components.

Method according to one of claims 3 to 5, characterized in that the at least one fluid jet (56) with a flat jet nozzle or a Hohlkegelstrahldüse or a full jet nozzle is generated and has a jet angle α, which is between 10 ° and 60 °, and preferably 20 ° and / or that the fluid jet (56) strikes the surface (12) with an average beam direction (57) at an impact point (63) at an angle of incidence β which corresponds to the angle between the central beam direction (57) and the vertical perpendicular (57). 61) corresponds to the mean beam direction (57) to the local tangential plane (59) in the point of impact (63), wherein for the impact angle β: 70 ° <β <90 °.

7. The method according to any one of claims 3 to 6, characterized in that the surface (12) simultaneously or sequentially with fluid jets (56) is acted upon, the a different beam angle α and / or a beam direction (57) with a have different impact angle ß on the surface (12).

8. The method according to any one of claims 3 to 7, characterized in that at least one operating parameter for the nozzle tool (28) depending on a measured or stored in a data storage intrinsic or extrinsic nature of the surface (12) of the workpiece (16, 16 ') adjusted or dependent on a measured intrinsic or extrinsic nature of the surface (12) of another workpiece whose surface (12) is already prepared in front of the surface of the workpiece for coating by applying a pulsating or continuous fluid jet (56) from the nozzle tool (28) has been.

A method according to claim 8, characterized in that the operating parameter for the nozzle tool (28) is a nozzle tool operating parameter from the group fluid pressure / fluid pressure in a nozzle chamber, feed rate of a nozzle tool (28) in the direction of a spindle axis (34), rotational speed of a nozzle tool ( 28) about a spindle axis (34), pulse frequency of the fluid jet (56), pulse duration of the fluid jet (56), amplitude and / or power of an ultrasonic generator and / or that the nature of the surface (12) of the workpiece (16, 16 ') or of the other workpiece is determined in a nondestructive measuring process, preferably in a nondestructive measuring process from the group of Tastschnittverfahren, confocal imaging with a microscope, imaging with an electron microscope.

Method according to claim 8 or claim 9, characterized in that the at least one operating parameter for the nozzle tool (28) is dependent on the location of the surface (12) and / or the geometry of the surface (12) and / or the intrinsic or extrinsic nature of the surface Surface (12) and / or measured for the adhesion of a coating applied relevant structural features of the surface of the workpiece (16, 16 ') or a similar workpiece (16, 16'), the surface of which has already been prepared for coating, or in A data store stored relevant structural features of the surface is set. Method according to one of claims 1 to 10, characterized in that the surface (12) of the workpiece (16, 16 ') before and / or after the application of a first fluid, in particular in the form of a liquid, with one of the first fluid rinsed different second fluid.

12. The method according to any one of claims 1 to 1 1, characterized in that the structure (15) a plurality of grooves (60, 60 ', 60 ") with a rectangular and / or round and / or at least one undercut, preferably comprises two undercuts, preferably dovetail-shaped groove profile and / or a plurality of strips, which are preferably formed as round bars (62) 13. Method for finishing the surface of a workpiece, in which the surface (12) of the workpiece (16, 16 '), characterized in that the surface (12) is prepared before coating with a method according to one of claims 1 to 12. 14. The method according to claim 13, characterized in that the surface (12) of the workpiece (16 , 16 ^' ) before the coating by treatment with blown air and / or by means of vacuum drying after-treated, in particular is dried 15. Method for finishing the surface of a Werkst ücks according to claim 13 or 14, characterized in that the surface (12) of the workpiece (16, 16 ') by means of a thermal spraying process, in particular by means of LDS coating or plasma coating or arc wire spraying or flame spraying is coated.

16. A method for refining the surface of a workpiece according to one of claims 13 to 15, characterized in that the surface che (12) of the workpiece (16, 16 ') is a wall of a cylinder bore in an engine block or in a cylinder housing or in a crankcase. 17. Plant (10) for preparing a surface (12) of a workpiece (16 ') for a coating, in particular system for carrying out the method specified in claims 1 to 12 and / or a method for finishing the surface of a workpiece according to the claims 13 to 16, characterized in that a fluid or a liquid to the surface (12) of the workpiece (16, 16 ') with a nozzle tool (28) can be fed, the one about a spindle axis (34) rotatable and in the direction the spindle axis (34) relative to the workpiece (16, 16 ') displaceable nozzle body with a nozzle chamber and at least one nozzle opening (30) for the provision of at least one continuous or pulsed fluid jet

(56), wherein for the nozzle tool (28) a control and / or regulating device (39) for setting at least one nozzle tool operating parameter from the group fluid pressure / fluid pressure in the nozzle chamber, feed rate in the direction of the spindle axis (34), Rotational speed about the spindle axis (34), pulse frequency of the fluid jet (56), pulse duration of the fluid jet (56), amplitude and / or power of an ultrasonic generator for generating a pulsed fluid jet (56) as a function of the location of the surface (12) and / or the geometry of the surface (12) and / or the intrinsic see or extrinsic nature of the surface (12) of the

Workpiece (16 ') or with a to the control and / or regulating device (39) connected measuring device (40) for the spatially resolved measurement of the relevant for the adhesion of a coating applied structural features measured structural features of another workpiece from a series of workpieces with one for that

Coating already prepared surface is provided.