阅读说明：本技术 用于加工工件的方法和组件 (Method and assembly for machining a workpiece ) 是由 W·乌尔里希 S·佩内尔特 于 2019-09-10 设计创作，主要内容包括：用于加工带有尤其在钻孔中的表面的工件(10)的方法,带有凹槽(14)和处在其间的桥接部(16)的凹槽结构(12)被引入到该表面中,其中,在凹槽结构(12)处可能构造有非期望的毛刺(18),其特征在于,为了检查且确定毛刺(18)的形成设置有测量设备(20),其将光线(24)发出到凹槽结构(12)的表面处且接收由表面所反射的光线(26),其中,毛刺形成的程度取决于所反射的光线(26)被确定。(Method for machining a workpiece (10) having a surface, in particular in a borehole, into which a groove structure (12) having grooves (14) and webs (16) located therebetween is introduced, wherein an undesired burr (18) may be formed at the groove structure (12), characterized in that a measuring device (20) is provided for checking and determining the formation of the burr (18), which emits light (24) at the surface of the groove structure (12) and receives light (26) reflected by the surface, wherein the extent of the burr formation is determined depending on the reflected light (26).)

1. Method for machining a workpiece (10) having a surface, in particular in a borehole, into which a groove structure (12) having grooves (14) and webs (16) located therebetween is introduced, wherein an undesired burr (18) may be formed at the groove structure (12), characterized in that a measuring device (20) is provided for checking and determining the formation of the burr (18), which emits light (24) at the surface of the groove structure (12) and receives light (26) reflected by the surface, wherein the extent of the burr formation is determined depending on the reflected light (26).

2. Method according to claim 1, characterized in that the determination of the burr formation is performed by means of the measuring device (20) simultaneously or immediately after the introduction of the groove structure (12).

3. A method according to claim 1 or 2, characterized in that the light (24) is coloured.

4. The method according to any one of claims 1 to 3, characterized in that the measuring device (20) has at least one confocal point sensor (22) which emits and receives the light rays (24, 26).

5. A method as claimed in any one of claims 1 to 4, characterized in that a reduction in the proportion between the reflected light rays (26) relative to the emitted light rays (24) is taken as the degree to which the burr formation increases.

6. Method according to one of claims 1 to 5, characterized in that the groove structure (12) is introduced with a material removal tool, in particular a milling or turning head.

7. Method according to claim 6, characterized in that the material removal tool is readjusted and/or replaced in the event that a predetermined value for the reflected light ray (26) is reached.

8. Method according to any one of claims 1 to 7, characterized in that a coating is applied to the groove structure (12) after introduction and inspection thereof.

9. Assembly for machining workpieces, in particular according to a method as claimed in one of claims 1 to 8, with a material removal device for introducing a groove structure (12) with grooves (14) and a web (16) located therebetween into a surface of the workpiece (10), characterized in that, for checking and determining the formation of a burr (18) at the groove structure (12), a measuring device (20) is provided which is designed to emit light (24) at the surface of the groove structure (12) and to receive light (26) reflected by the surface, wherein the extent of the burr formation can be determined depending on the reflected light (26).

10. Assembly according to claim 9, characterized in that the measuring device (20) is arranged at the material removal apparatus.

11. An assembly according to claim 9 or 10, characterized in that the groove structure (12) is introduced into the workpiece (10) with at least one material removal tool and is provided with an indicator which indicates when to replace the at least one material removal tool depending on the measurement results of the measuring device (20).

12. Assembly according to any one of claims 1 to 11, characterized in that the measuring device (20) has at least one confocal point sensor (22) which emits and receives the light rays (24, 26).

Technical Field

The invention relates to a method for machining workpieces having a surface, in particular in boreholes, into which a groove structure (rilens truktur) having grooves and webs (Steg, sometimes referred to as ribs) located therebetween is introduced, according to the preamble of claim 1, wherein undesirable burrs may be formed at the groove structure.

The invention further relates to an assembly for machining a workpiece with a material removal device for introducing a groove structure with grooves and a bridge lying therebetween into a workpiece surface according to the preamble of claim 9.

Background

In the case of metal workpieces, a surface coating may be required for certain purposes of use. For example, in the case of an engine block (sometimes referred to as an engine block) constructed of aluminum material, a surface coating of the cylinder rail (sometimes referred to as the cylinder face) may be necessary in order to form a functionally robust friction system with the piston rings/pistons. For this purpose, it is known to apply a metallic surface coating, for example by means of plasma spraying. It has proven particularly suitable to connect the coating material and the base material (i.e. the aluminum material) to one another in a form-fitting manner. For this purpose, the surface to be coated is activated, i.e. roughened or provided with a defined groove structure.

Such a method is known, for example, from EP 3132893 a1 of the applicant, in which macroscopic contour elements are introduced into the surface to be coated.

Different contour shapes of such macroscopic contour elements for the activation surface are known from DE 102013211324 a1, for example groove structures with a rectangular contour or a dovetail contour. These groove structures are cut into the surface to be coated with a cutting tool before coating.

In the case of this machining, undesirable burrs may form at the groove structures. These burrs may be the starting point for layer defects in the case of the subsequent coating. As a result, the layer may not be sufficiently or too highly structured in the region of the burr, so that a defect site is formed at the workpiece. In particular in the case of coatings for cylinder rails at the engine block, the coatings are subjected to high thermal and mechanical loads, so that such coating defects are unacceptable. Such coating defects can form larger damage points during engine operation, which in the worst case can lead to a failure of the engine as a whole.

In production, it is therefore necessary to monitor the workpiece in view of the formation of the burr at the groove structure and to determine the height of the formed burr. It is known to detect these burr heights under an optical microscope, either via micrographs (Schliffbild), i.e. via destructive testing (zeroth sner fur), or via separately made stamps (abductkmassen). Such subsequent inspections are cumbersome, so that they are generally not carried out at each workpiece, but rather intermittently on a statistical basis after a certain number of operations, for example after every 50 components. In the case of the known test, feedback is thus obtained relatively late about the component quality of a production batch. Production is often interrupted until there is a measurement for a production lot. Furthermore, in the case of such statistical methods, the basic risk is that an unexpected deviation is not detected or is detected later.

Disclosure of Invention

The invention is based on the object of specifying a method and a component for machining workpieces in the case of the formation of groove structures, in which the formation of undesired burrs can be checked efficiently and reliably.

According to the invention, this object is achieved, on the one hand, by a method with the features of claim 1 and, on the other hand, by an assembly with the features of claim 9. Preferred embodiments of the invention are specified in the respective dependent claims.

The method according to the invention is characterized in that, for checking and determining the formation of burrs, a measuring device is provided which emits light at the surface of the groove structure and receives light reflected by the surface, wherein the extent of the formation of burrs is determined depending on the reflected light.

The method according to the invention can be performed at individual workpieces or even all workpieces without damage and thus efficiently. The invention is based on the recognition that the formation of the burr at the groove structure to be introduced and its height have an influence on the reflection properties of the workpiece surface in the case of irradiation with light. According to the invention, a measuring device is provided which emits light at the surface of the groove structure and receives the light reflected thereby, wherein the proportion of the reflected light is to the extent of burr formation at the workpiece.

A preferred embodiment of the invention consists in that the burr formation is carried out simultaneously or immediately after the introduction of the groove structure by means of a determination by means of a measuring device. The measuring device can be located immediately at the processing device or immediately downstream of the processing device. This makes it possible to determine the burr formation preferably rapidly at each workpiece. This offers the possibility of counteracting the initial (einetzend) excessive burr formation. Thus, the method according to the invention may contribute to reducing scrap or in general even to zero defect production.

In principle, any type of light can be used for the measuring device, in particular monochromatic light can likewise be used. A particularly reliable measurement result is obtained according to a further development of the invention in that the light is colored.

In addition, it is possible in principle for the measuring device to have at least one separate light source and at least one separate sensor for receiving the reflected light. In one embodiment of the invention, it is preferred that the measuring device has at least one confocal point sensor (konfokale Punktsensor) which emits and receives light. Preferably, the confocal point sensor is arranged here perpendicularly to the objective above the surface to be examined. A particularly reliable value in view of the reflection of the light rays at the surface and thus the formation of relative burrs can be determined by the confocal arrangement of the light source and the point sensor.

In one embodiment of the invention, the reduction in the ratio of reflected light to emitted light is regarded as the degree of increased burr formation. In this case, it is possible to start with a substantially smooth and thus burr-free surface which reflects a high proportion of the emitted and preferably normally incident light back again perpendicularly. The stronger the burr formation occurs, the more and/or the higher the burr, the more the light is deflected laterally by the burr side edges, so that these light no longer pass back to the measuring device. The larger this scattering effect, the higher the burr formation.

In principle, the groove structure can be introduced into the surface of the workpiece in any suitable manner, for example, also by means of a laser. According to one embodiment of the method according to the invention, a particularly economical method for machining a workpiece consists in that the groove structure is introduced using a material removal tool, in particular a milling head (Fr ä skopf) or a turning tool (Drehmei beta el). Corresponding material removal devices with milling or turning heads, also called grooving tools (einstehmei beta) are sufficiently known. This cutting process is particularly economical, but is also associated with an increased risk of burr formation.

The present invention recognizes that not every burr at the groove structure introduced is disadvantageous for the subsequent coating. But a smaller burr may even contribute to a better interconnecting effect with the applied coating. In accordance with an embodiment of the invention, it is preferred that the material removal tool is readjusted and/or replaced when a predetermined value for the reflected light is reached. In this way, it is possible to intervene in the production steps of material removal and in the production of the groove structure in a timely manner before excessive burr formation occurs. The formation of an undesirably large burr can therefore likewise be counteracted over a longer period of time.

Furthermore, it is advantageous according to a development of the method according to the invention that a coating is applied to the groove structure after the introduction and the inspection of the groove structure. The coating is in particular a metal coating which is applied by spraying metal particles, in particular according to the plasma spraying method.

In view of an assembly for machining a workpiece, the invention is characterized in that for checking and determining the formation of burrs at the groove structures a measuring device is provided which is configured to emit light at the surface of the groove structures and to receive light reflected by the surface, wherein the extent of the formation of burrs can be determined depending on the reflected light.

The assembly according to the invention may be used in particular for carrying out the previously described method according to the invention. Here, it is possible to obtain the advantages described previously.

The measuring device provided according to the invention may itself have a computing unit which determines the still permissible or no longer permissible extent of the burr formation depending on the measured values. In addition or alternatively, the measuring device can also be connected to a central processing unit, in particular a control unit, of the overall assembly, by means of which the measured values of the measuring device are evaluated and a decision for continuing the method or for interrupting, for example, for changing a material removal tool, is made according to a predefined program structure.

In principle, the measuring device may be downstream of the material removal device. For an efficient process flow, it is provided according to a further development of the invention that the measuring device is arranged on the material removal device. In this way, the machining result can be checked very quickly overall and, in particular in the case of the next machining operation, a correction, in particular a readjustment or a replacement of the tool can be carried out already or even also in the case of an operating machining operation.

In this case, it is particularly advantageous according to one embodiment of the invention if the groove structure is introduced into the workpiece with at least one material removal tool and an indicator (Anzeige) is provided, which indicates when to replace the at least one material removal tool depending on the measurement result of the measuring device. Depending on the indicator, the operator may then quickly replace the material removal tool, for example. Alternatively, the assembly can also be designed in such a way that an automatic change process is initiated by the control device.

In principle, the measuring device has at least one light source and at least one light-sensitive sensor. A preferred embodiment of the invention consists in that the measuring device has at least one confocal point sensor which emits and receives light. The confocal point sensor is preferably arranged here perpendicularly on the workpiece surface to be examined. In this case, the point sensor serves both as a light source for emitting light preferably perpendicularly onto the workpiece surface and for the confocal reception of light reflected perpendicularly from the surface. The point sensor can be equipped with a corresponding objective for confocal operation.

The measuring device or the at least one point sensor can be arranged on a support which is movable relative to the surface of the workpiece, in particular in the case of measurements.

Drawings

The invention is further explained below by means of a preferred embodiment, which is schematically shown in the drawing.

Detailed Description

The sole figure shows a strongly schematic enlarged partial sectional view of a workpiece 10, in which a groove structure 12 with cross-sectionally dovetail-shaped bridges 16 and grooves 14 lying therebetween is introduced into the surface with material removal. The groove structure 12 is shown strongly enlarged, wherein the real workpiece 10 can be a macroscopic groove structure with a groove depth of several millimeters or less. The schematically illustrated workpiece 10 can be, in particular, an engine block with a cylinder bore, in whose bore wall a recess arrangement 12 is introduced.

By means of a measuring device 20 of a confocal point sensor 22, which is shown very schematically, light rays 24 are emitted approximately perpendicularly onto the surface of the groove structure 12, in particular onto the upper side of the bridge 16. The light ray 24 is reflected at the surface of the groove structure 12 and may reach back into the confocal point sensor 22 of the measurement device 20 as reflected light ray 26. The smoother the surface of the groove structure 12, the higher the fraction of the reflected light rays 26 that reach back into the confocal point sensor 22.

In the case of a material-removing introduction of the groove structures 12 into the surface of the workpiece 10, an undesired burr 18, in particular at the bridges 16 of the groove structures 12, may form, as is shown intuitively on the right-hand side of the drawing, in particular depending on the state of the machining tool, but also depending on the material of the respective workpiece 10.

If the point sensor 22 of the measuring device 20 is moved past the surface area with the burr 18, as opposed to a smooth surface, a portion of the emitted light ray 24 is emitted at the side of the burr 18 as a laterally reflected light ray 26 b. This light is therefore no longer receivable and detectable by the confocal point sensor 22 of the measuring device 20. Only a portion of the vertically reflected light ray 26a reaches back into the point sensor 22.

The measuring device 20 is in any case configured together with a control device or a computing unit, not shown, which indicates the extent, in particular the number and/or size of the burrs 18 at the groove structures 12 of the workpiece 10, depending on the ratio between the emitted light rays 24 and the portion of the reflected light rays 26 reaching back into the point sensor 22. Depending on the result of the measurement, a signal may then be issued or such a replacement may be caused automatically, for example indicating a necessary replacement of the machining tool in a preceding machining step of the introduction of the groove structure 12.

The surface coating of the surface of the workpiece 10 with the groove structures 12 can be realized immediately after the measurement. This can be achieved in particular by spraying the molten metal particles by means of a sufficiently known spraying method.