Wall element

Abstract

A work container for a vibratory finishing system has a wall component that is provided with macro- and micro-surfaces.

Description

[0001] The invention relates to a wall component of a work container for a vibratory finishing machine, comprising an outer surface extending around a central axis and an inner wall with a profile having a microstructure in the form of parallel micro-raised areas and micro-depressions. Such a wall component can be used together with a rotary table forming the bottom of the work container in vibratory finishing processes of any kind.

[0002] The inner wall of such work containers should not be perfectly smooth, as this can lead to the moving components sticking. An inner wall with microstructures can prevent sticking, especially if the structures, in the form of groove-like protrusions and depressions, are smaller than the characteristic dimensions of the components. However, surfaces uniformly structured across the entire container wall can, in certain cases, behave fluid-dynamically like a smooth wall. Components are then moved towards the inner wall by the relative motion during vibration or centrifugal machining and subsequently follow it in laminar flow patterns parallel to the container wall. Cross-mixing, i.e., in the radial direction, does not occur.

[0003] It has therefore been proposed to install deflectors on the inner wall that impart a radial motion component to the components moving parallel to the container wall. This deflects the components towards the center in round containers, disrupting the laminar flow pattern.

[0004] When processing small components (e.g., in all dimensions up to approximately 50 mm), especially flat or compact components such as plates, bolts, rings, ring slides, etc., uneven results can occur in vibratory finishing processes if the components do not have essentially the same residence time in all areas of the processing volume. This can occur in principle with all vibratory finishing processes, such as vibration processes or centrifugal finishing systems with abrasive media, or even in part-to-part processing in preferably round, but also rectangular containers.

[0005] Uneven residence time distributions of the components in such processes occur when, for example, components are held to the walls of the containers by adhesion and are therefore no longer permanently circulated together with the other parts.

[0006] Furthermore, components can be stopped in flow dead zones, such as vortices behind flow deflectors or drive elements. In these flow dead zones, the parts move only minimally against each other or against the grinding media, thus significantly reducing the effective machining time of these parts.

[0007] Components and grinding media (with / without process fluid such as water) behave very similarly to pure fluid flows. With regard to the use of flow deflectors, this means that the flow near the wall is given a radial component towards the center of the container by the deflector. However, this can typically create dead zones in front of and behind the deflector due to turbulence in the deflector's backwater area or flow shadow. In these dead zones, adhesion can also occur on smooth surfaces on the wall or the deflector.

[0008] It is therefore the object of the present invention to provide a wall component of the type described above with which a working container can be created with which a uniform processing of the components without the formation of flow shadows can be achieved in a vibratory finishing process.

[0009] This problem is solved by the features of claim 1, and in particular by superimposing a macrostructure in the form of macro-protrusions onto the microstructure present on the inner wall. The macrostructure acts as a flow deflector to impart a radial component to the components inside the container, while the microstructures serve to counteract laminar flow parallel to the container wall. This prevents the components from adhering to the inner wall during processing and ensures they are reliably carried along by the flowing process fluid (processing fluid, e.g., water with / without additives, components, and / or grinding media) and thus returned to uniform processing. Here, a microstructure (unlike in microtechnology) is not necessarily understood to be a dimension that can still be meaningfully expressed in micrometers, but rather a structure with dimensions in the range of mm to cm.

[0010] Advantageous embodiments of the invention are described in the description, the drawing and the dependent claims.

[0011] According to a first advantageous embodiment, the macro-protrusions can extend at least predominantly parallel to the micro-protrusions. In this embodiment, the macro-protrusions form crests of waves on the inner wall that extend in a direction parallel to the central axis and parallel to the micro-protrusions. The surface of the macro-protrusions is therefore also provided with micro-protrusions, which, in particular, do not differ from the micro-protrusions outside the macro-protrusions. In this embodiment, the micro-protrusions and depressions in the area of ​​the macro-protrusions thus have the same cross-sectional shape and surface contour as those outside the macro-protrusions.

[0012] According to a further advantageous embodiment, the macro-protrusions in a section plane perpendicular to the central axis can have an outer contour that is symmetrical to a radial jet and, in particular, circular arc-shaped. This achieves the advantage that, due to the symmetrical design of the macro-protrusions, the components sliding along the inner wall during vibratory finishing do not form flow dead zones, but rather flow uniformly along the convex protrusion formed by the macro-protrusions in the region of the inner wall, while still imposing a radial velocity component on the components. At the very least, the size of the flow dead zones is significantly reduced, e.g., to the size range of a minimal component dimension.

[0013] According to a further advantageous embodiment, the micro-raised areas and depressions in a section plane perpendicular to the central axis can have a contour that is symmetrical to a radial ray and, in particular, circular arc-shaped. This allows the inner wall to be given a grooved structure containing wave crests and troughs whose curvature is uniform and without discontinuities. However, it is also possible to impose other cross-sectional shapes on the microstructure, for example, raised areas with a trapezoidal or rectangular cross-sectional shape.

[0014] According to a further advantageous embodiment, two macro-protrusions can be diametrically opposed to each other. Particularly good results were achieved with this embodiment in initial trials.

[0015] According to a further advantageous embodiment, all elevations, i.e., those of the microstructure as well as those of the macrostructure, can be part of a coating made of plastic, for example a polyurethane coating.

[0016] According to a further aspect, the present invention relates to a work container for a vibratory finishing system, comprising a wall component of the type described above and a base. The base can be rigidly connected to the wall component or designed as a rotary table to rotate the components within the container.

[0017] According to a further aspect, the present invention relates to a method for vibratory finishing of workpieces in a work container of the type described above, wherein the dimensioning of the microstructure and the macrostructure is selected depending on a minimum dimension Dmin of the components to be processed. The minimum dimension Dmin of the components is understood to be the smallest characteristic dimension of the components. For cylindrical components, this is, for example, the diameter of the components. For cuboid components, this is, for example, the smallest extent along all three spatial axes.

[0018] In the inventive method, the geometry of the micro-recesses and macro-protrusions is selected such that the micro-recesses have a circular arc contour symmetrical to a radial beam with a radius Rmicro, while the macro-protrusions have a circular arc contour symmetrical to a radial beam with a radius Rmacro. If the geometries are further selected such that Rmacro is larger than Rmicro, Rmicro is between 0.5 and 2 times Dmin, and / or Rmacro is between 3 and 50 times Dmin, then it can be prevented that the components both slide laminarly along the inner wall and become stuck in the recesses. Furthermore, it can be advantageous if Rmacro is at least 10 times, in particular at least 20 times, and in particular at least 30, 40, or 50 times larger than Rmicro in order to achieve advantageous flow behavior in the vibratory finishing process.

[0019] The present invention is described below by way of example with reference to an advantageous embodiment and the accompanying drawings. These show: Fig. 1 shows a section through a work container with a wall component and a turntable as a base; Fig. 2 shows a sectional top view of the work container. Fig. 1 ; and Fig. 3 a section through a macrostructure of the inner wall.

[0020] Fig. 1 Figure 1 shows a work container 10 for a vibratory finishing machine, which is composed of a wall component 12 and a base, which in the illustrated embodiment is designed as a rotary table 14. In the illustrated embodiment, the wall component 12 is designed as a hollow cylinder with a central axis M, which simultaneously forms an axis of rotation of the rotary table 14. The wall component 12 has a circular cylindrical outer surface 16 and an inner wall 18, which is formed by a coating 20, for example a polyurethane coating 20, applied to a steel or plastic shell 22 forming the outer surface 16.

[0021] The rotary plate 14, which forms the base of the work container 10, is also provided with a coating 24 on its inner side, with drainage openings 26 extending through the coating 24 and the base 14. Furthermore, the coating 24 has radially extending rib-shaped projections 28, which serve as drivers.

[0022] As the figures illustrate, the inner wall 18 of the wall component 12 is provided with a profile. This profile consists, on the one hand, of a microstructure 30 in the form of a multitude of parallel micro-protrusions and micro-recesses located along the entire inner circumference in the axial direction of the inner wall 18. The microstructure 30 extends in the axial direction, i.e., parallel to the central axis M, from the top surface of the wall component 12 to a region where the inner wall 18 begins to taper slightly towards the central axis M.

[0023] Furthermore, a macrostructure in the form of macro-protrusions 32 is superimposed on the microstructure 30 on the inner wall 18. These extend predominantly parallel to the micro-protrusions 30, but may be chamfered at their upper and / or lower axial end, resulting in inclined surfaces 34 and 36 sloping towards each other.

[0024] Fig. 3 Figure 1 shows a section through the coating 20 of the working vessel 10 in the area of ​​a macro-protrusion 32. As can be seen, the surface of the macro-protrusions 32 facing the interior of the vessel is provided with the same micro-protrusions 30 as the rest of the inner wall. The micro-protrusions 30 – and correspondingly also the micro-recesses formed by the micro-protrusions – have the same cross-sectional shape in the area of ​​the macro-protrusions 32 as outside the macro-protrusions 32, namely a cross-sectional shape in a section plane perpendicular to the central axis M and a radial ray 38 ( Fig. 2 ) symmetrical arc-shaped contour. In cross-section, the micro-elevations 30 thus have the shape of a periodic wave, as is characteristic, for example, of sine waves or waveforms composed of circular segments, whereby the circular segments are typically smaller than semicircles.

[0025] The macro-protrusions 32 also possess an outer contour symmetrical to a radial ray 38 and circular arc-shaped in a section plane perpendicular to the central axis M, the radius of which originates outside the interior of the container. The protrusions and depressions of the microstructure each have a radius Rmicro, which is the same for both the protrusions and the depressions, in order to form the sinusoidal wave structure of the microstructure 30. Here, Rmicro can be, for example, 4 to 5 mm and Rmacro, for example, 80 to 150 mm.

[0026] Finally, it clarifies Fig. 2, that in the illustrated embodiment two macro protrusions 32 are diametrically opposed to each other, i.e., in the illustrated embodiment a total of four macro protrusions 32 are provided, which are superimposed on the micro protrusions 30.

Claims

1. Wall component (12) of a work container (10) for a vibratory finishing system, which has an outer surface (16) extending around a central axis (M), in particular a circular cylindrical surface, and an inner wall (18) which is provided with a profile having a microstructure (30) in the form of parallel micro-raised areas and micro-depressions, characterized by that The microstructure (30) is superimposed on a macrostructure in the form of macro elevations (32).

2. Wall component according to claim 1, characterized by that the macro surveys (32) extend at least to a predominant extent parallel to the micro surveys (30).

3. Wall component according to claim 1 or 2, characterized by that the micro-elevations (30) and micro-depressions in the area of ​​the macro-elevations (32) have the same cross-sectional shape as those outside the macro-elevations.

4. Wall component according to one of the preceding claims, characterized by thatthe macro-elevations (32) in a section plane perpendicular to the central axis (M) have an outer contour that is symmetrical to a radial ray (38) and in particular circular arc-shaped.

5. Wall component according to one of the preceding claims, characterized by that the micro-elevations (30) and micro-depressions in a section plane perpendicular to the central axis (M) have a contour that is symmetrical to a radial ray (38) and in particular arc-shaped.

6. Wall component according to one of the preceding claims, characterized by that Each pair of macro-surveys (32) are diametrically opposed to each other.

7. Wall component according to one of the preceding claims, characterized by that the macro-raised features (32) are chamfered at at least one axial end.

8. Wall component according to one of the preceding claims, characterized by thatall elevations (30, 32) are part of a coating (20), in particular made of plastic.

9. Working container (10) for a vibratory finishing system, comprising a wall component (12) according to one of the preceding claims and a base (14).

10. Working container according to claim 9, characterized by that the floor is a turntable (14).

11. Method for vibratory finishing of components in a work container (10) according to claim 9 or 10, wherein the components have a minimum dimension of D min possessing microrecesses in a section plane perpendicular to the central axis (11) a circular arc-shaped contour symmetrical to a radial ray (38) with a radius R Mikro possess, and the macro-elevations (32) in a section plane perpendicular to the central axis (11) form a circular arc-shaped contour symmetrical to a radial ray (38) with a radius R Makro possess, where R Makro greater than RMikro is, and R Mikro between 0.5 and 2 times D min , and / or R Makro between 3 and 50 times D min amounts.

12. Method according to claim 11, wherein R Makro at least ten times or at least twenty times greater than R Mikro is.

13. Method according to claim 11, wherein R Makro at least twenty times larger than R Mikro is.

14. Method according to claim 11, wherein R Makro at least thirty times or at least forty times greater than R Mikro is.

15. Method according to claim 11, wherein R Makro at least fifty times greater than R Mikro is.

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