Methods For Producing and Using a Textile Machine Tool Part

Abstract

A textile machine tool part (11) that is used in textile processing in a textile machine and a method for producing same are disclosed. The textile machine tool part (11) has a tool core (16) made of a core material and is coated, at least in part, with a wear-resistant coating. The wear-resistant coating (17) is applied to a core surface (18) that has a first microstructure (19). The first microstructure (19) is preferably created using electrochemical etching in the core surface (18). The wear-resistant coating (17) applied thereto is preferably applied directly to at least a section of the core surface (18) having the first microstructure (19) using electrochemical deposition and has a layer thickness of a maximum of 20 μm.

Claims

1. A method for producing a textile machine tool part, the method comprising: producing a tool core (16) from a core material; creating a microstructure (19) in at least one section of a core surface (28) of the tool core (16), wherein the microstructure (19) of the core surface (18) has depressions and elevations that are connected to one another, wherein the depressions are depressed in a concave manner relative to a reference plane, while the elevations are raised in a convex manner relative to the reference plane, wherein a diameter of individual ones of the depressions and/or elevations is at most 60 μm and wherein a distance between a maximum depth of individual ones of the depressions and a maximum height of immediately adjacent elevations is at least 10 μm and at most 60 μm; and coating at least part of the core surface (18) having the microstructure (19) with a wear-resistant coating (17) that has a layer thickness (d) of a maximum of 20 μm such that the wear-resistant coating (17), due to the microstructure (19) of the core surface (18), also has a microstructure (22).

2. The method according to claim 1, wherein creating the microstructure (19) in the at least one section of the core surface (18) comprises using an electrochemical etching process.

3. The method according to claim 1, wherein coating the at least part of the core surface (18) having the microstructure (19) comprises applying the wear-resistant coating (17) immediately after the microstructure (19) of the core surface (18) is created.

4. The method according to claim 1, wherein coating the at least part of the core surface (18) having the microstructure (19) comprises applying the wear-resistant coating (17) using electrochemical deposition.

5. The method according to claim 2, wherein the electrochemical etching process has a current density of 20-40 A/dm2 and an etching duration of 30 seconds to 1200 seconds.

6. The method according to claim 2, further comprising using the tool core (16) as anode in a bath of chromium acid solution having from 50 to 300 grams of chromium trioxide per liter.

7. The method according to claim 6, wherein the bath has a temperature of 20° C. to 60° C.

8. The method according to claim 6, wherein a dwell time of the tool core (16) in the bath is from 10 seconds to 1800 seconds.

9. The method according to claim 6, wherein the bath contains 0.5 to 2.5% sulfuric acid by weight.

10. The method according to claim 6, wherein the bath contains a catalyst having a concentration in a range of 1-10 to 1-20 relative to the chromium trioxide content.

11. The method according to claim 10, wherein the catalyst is a sulfonic acid.

12. The method according to claim 11, wherein the sulfonic acid comprises at least one of methane sulfonic acid, dimethanesulfonic acid and naphthalene sulfonic acid.

13. A method of using a textile machine tool part (10, the textile machine tool part (11) comprising: a working section (12) configured to contact a thread or yarn; a holding section (14) configured to be held or moved by a textile machine; a tool core (16) that comprises a core material; wherein the tool core (16) in the working section (12) has a core surface (18) having a microstructure (19), at least in one section of the core surface; wherein the microstructure (19) of the core surface (18) has depressions and elevations that are connected to one another, wherein the depressions are depressed in a concave manner relative to a reference plane, while the elevations are raised in a convex manner relative to the reference plane, wherein a diameter of individual ones of the depressions and/or elevations is at most 60 μm and wherein a distance between a maximum depth of individual ones of the depressions and a maximum height of individual ones of immediately adjacent elevations is at least 10 μm and at most 60 μm; wherein the core surface (18) having the microstructure (19) is coated, at least in part, with a wear-resistant coating (17) that has a layer thickness (d) of a maximum of 20 μm and wherein an outer surface of the wear-resistant coating (17) also has a microstructure (22) due to the microstructure (19) of the core surface (18); and wherein the outer surface of the wear-resistant coating (17) forms at least part of an outer surface of the textile machine tool part (11); wherein the method comprises: producing or processing a textile material in a textile machine with at least one elastane yarn that comes into contact with the textile machine tool part (10).

14. The method according to claim 13, wherein a fineness of the at least one elastane yarn is at least 20 den or 22 dtex.

15. The method according to claim 13, wherein a fineness of the at least one elastane yarn is a maximum of 40 den or 44 dtex.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 depicts a side view of an example of a textile machine tool part that is formed by an eye needle;

[0033] FIG. 2 is a partial sectional view of the eye needle from FIG. 1, according to section line II-II in FIG. 1;

[0034] FIG. 3 is a schematic depiction of a sub-region III in FIG. 2 and illustrates a part of the tool core and the wear-resistant coating applied thereto in a highly simplified sectional depiction;

[0035] FIG. 4 provides a perspective photographic partial depiction of the eye needle from FIG. 1 and illustrates a wear-resistant coating having a microstructure;

[0036] FIG. 5 illustrates a sub-region IV of the wear-resistant coating of the eye needle from FIG. 4; and,

[0037] FIG. 6 is a flow chart of an exemplary method for producing a textile machine tool part, for instance of the eye needle according to FIGS. 1-5.

DETAILED DESCRIPTION

[0038] FIG. 1 is a schematic side view of an eye needle 10 that forms a textile machine tool part 11. Another needle, such as, for example, a machine knitting needle, a machine sewing needle, a machine felting needle, or a machine tufting needle, may also form the textile machine tool part instead of an eye needle 10. Instead of being formed by a needle, the textile machine tool part may also be formed by a system part of a textile machine, for example, a sinker, a thread guide system part, or a control or coupling part. A textile machine tool part is in particular a tool part or system part that is attached to the textile machine and that is present in the textile machine for processing threads or yarns and that may come into contact with the yarn or threads, for instance during operation.

[0039] The eye needle 10 according to the example has a working section 12 in that the eye needle 10 has an eye 13 for guiding a thread or yarn. A holding section 14 by means of which the eye needle is attached to a needle holder 15 is connected to the eye 13 at the working section 12. As a rule, a plurality of eye needles 10 with aligned eyes 13 are arranged in such a needle holder 15.

[0040] Other textile machine tool parts or textile tools also have a working section 12 and a holding section 14. For example, a machine sewing needle or a machine felting needle has working section having the needle tip and has a holding section in the region of the needle shaft, by means of which holding section the needle is held in the machine. A knitting machine needle has a working section with the needle hook and at an interval therefrom has a holding section having a foot part or the like by means of which the machine knitting needle may be moved in a guide channel of the knitting machine, for example. Sinkers or other system parts may have a working section, which comes into contact with a yarn, and a holding section by means of which the part is borne or fixed or caused to move.

[0041] FIG. 2 illustrates a partial cut-away depiction according to the line of intersection II-II through the eye 13 (see FIG. 1). It may be seen that the eye needle 10 has, at least in the working section 12, a tool core 16 made of a core material and has a wear-resistant coating 17 that is made of a material that differs from the core material and that is applied directly to the tool core 16. The core material is preferably formed by a metal or a metal alloy and comprises a steel allow, for example. The wear-resistant coating 17 in the exemplary embodiment is formed by a hard chromium coating. It may alternatively be a DLC coating, a carbidic coating, or a nitridic coating.

[0042] The wear-resistant coating 17 is applied, for example, only in the working section 12 of the eye needle 10 or of the textile machine tool part 11. Other regions, for example the holding section 14, are not covered with the wear-resistant coating 17. Depending on the precise function of the specific textile machine tool part, it may be sufficient merely to provide the wear-resistant coating 17 only to a section that is subject to wear. However, it is also possible to coat the entire textile machine tool part 11 with the wear-resistant coating 17.

[0043] The wear-resistant coating 17 is applied directly to the core material of the tool core 16 without any intermediate coating. A core surface 18 of the core material 16 has a first microstructure 19 in the section in which the wear-resistant coating 17 is applied. The first microstructure 19 is illustrated, in a highly schematic depiction, in FIG. 3, which depicts an enlarged excerpt (Region III in FIG. 2) of the core material and wear-resistant coating 17. The depiction in FIG. 3 is highly simplified and not to scale. As may be seen, the first microstructure 19 is formed on the core surface 18 by adjacently arranged concave first depressions 20 and convex first elevations 21. The depressions 20 and/or the first elevations 21 preferably have a spherical segment-shaped, spherical contour, each having a radius Ri, wherein i represents an index that describes the allocation of the particular radius to a specific first depression 20 or first elevation 21. For example, FIG. 3 illustrates a first radius R1 for a first depression 20 and a second radius R2 for a first elevation 21.

[0044] The wear-resistant coating 17 is applied to this first microstructure 19. The layer thickness d of the wear-resistant coating 17 is at least 2 μm and a maximum of 20 μm. In additional exemplary embodiments, the layer thickness d of the wear-resistant coating 17 may also be a maximum of 10 μm or a maximum of 7 μm.

[0045] Because of this layer thickness d of the wear-resistant coating 17, the latter also embodies a microstructure, which here is called the second microstructure 22. Analogous to the first microstructure 19, the second microstructure 22 thus forms second depressions 22 and second elevations 24 that are connected to one another. Analogous to the first microstructure 19, the second depressions 23 and the second elevations 24 each have a spherical segment-shaped contour with a radius Ri, wherein in FIG. 3, as an example, a third radius R3 is recorded for a second depression 23 and a fourth radius R5 is recorded for a second elevation 24.

[0046] Seen in a section through the first microstructure 19 of the core surface 18 and of the second microstructure 22 of the wear-resistant coating 17 (FIG. 3), the sectional contour lines of the microstructures 19, 22 have a constant course. Their slope (first derivative) is also preferably constant at each point of the curve of the sectional contour lines of the microstructures 19 and 22.

[0047] In a modification to the schematic embodiment according to FIG. 3, it is also possible for only the depressions 20 and 23 or only the elevations 21 and 24 of the specific microstructure 19 and 22 to have a spherical segment-shaped form. The radii of the first and second depressions 20, 23 and/or those of the first and second elevations 21, 24 may vary in a prespecified region and may be, for instance, a maximum of 20-30 μm and a minimum of 5-10 μm. An interval z of a minima of a second depression 23 from the maximum of the immediately adjacent second elevations is preferably a maximum of 40-60 μm and a minimum of 10-20 μm.

[0048] The layer thickness d of the wear-resistant coating 17 is essentially constant. Within a specific surface having the surface area of 1 mm.sup.2, preferably a square surface of 1 mm×1 mm, the layer thickness d deviates a maximum of 10% or a maximum of 1 μm. The figures for the layer thickness d apply for the entire wear-resistant coating 17 outside of an edge zone 25 immediately adjacent to an edge 26 of the wear-resistant coating 17. Within this edge zone 25, the layer thickness d decreases continuously to the edge 26 of the wear-resistant coating.

[0049] FIG. 4 and FIG. 5 are photographs of the second microstructure 22 of the wear-resistant coating 17. In this exemplary embodiment, only the second elevations 24 have a spherical segment-shaped contour in the region of their maximum, but not the depressions 23.

[0050] One preferred method for producing a textile machine tool part 11 and, as an example, the eye needle 10 described in the foregoing is described in the following using FIG. 6.

[0051] In a first method step S1 the tool core 16 is produced from core material, for example by molding and/or mechanically processing a core material. The tool core 16 acquires the appropriate shape that determines the shape of the later textile machine tool part 11 and, for example, the eye needle 10.

[0052] Then, in a second method step S2, at least in one section of the core surface 18 of the tool core 16, the first microstructure 19 is created, for example using an electrochemical etching process. For this, a chromic acid solution having 50-300 g chromium trioxide per liter at a temperature of 20° C. to 60° is used. The dwell time of the tool core 16 in the bath, depending on the depth or height of the first depressions 20 and first elevations 21 to be produced, is between 10 seconds up to 1800 seconds. The tool core 16 is used as the anode (positive pole of the voltage), so that core material on the core surface is removed and migrates into the electrolytic solution. Less soluble components of the structure of the core material migrate less rapidly into the solution. When etching the first microstructure 19, for example, a current density of 20-40 A/dm.sup.2 may be used, wherein the etching duration is preferably 30 seconds to 1200 seconds. The desired first microstructure 19 may be dimensioned using the etching duration and the current density.

[0053] Since the first microstructure is created using an etching process, immediately after the second method step S2, the wear-resistant coating 17 may be applied “wet in wet” in a third method step S3. There is no drying and there are no other intermediate steps during the second method step S2 or during the third method step S3, for example. In the exemplary embodiment, a hard chromium coating is applied as the wear-resistant coating 17 using electrochemical deposition. At least one section of the tool core 16 having the first microstructure 19 is dipped into an electrolytic bath, wherein the tool core 16 acts as cathode (negative pole) so that material from the bath deposits on the core surface 18 with the first microstructure 19. The bath contains, for example, 170-270 g chromium trioxide per liter, 0.5-2.5% by weight sulfuric acid, and a special catalyst. The special catalyst may be, for example, a sulfonic acid and may have a concentration in the range of 1:10-1:20 relative to the chromium trioxide content of the chromium bath. The temperature of the bath is 50° C. to 70° C. Methane sulfonic acid, dimethanesulfonic acid, or naphthalene sulfonic acid may be used as the sulfonic acid. The current density is 15-50 A/dm.sup.2, for example. The dwell time in the electrolytic bath is selected such that the wear-resistant coating 17 has a layer thickness of a maximum of 20 μm or a maximum of 10 μm and preferably a maximum of 7 μm. The minimum layer thickness is 1 μm. During the process of coating with the wear-resistant coating 17 using electrochemical deposition, the form of the second microstructure 22 may be influenced by a pulsed current, the current density, temperature, bath concentration, and other parameters. The second microstructure 22 depends on the aforesaid coating parameters and also on the dimensioning and embodiment of the first microstructure 19 on the core surface 18. For instance, elevations and depressions (mountains and valleys) of the second microstructure 22 may be formed that have hemispherical contours.

[0054] The invention relates to a textile machine tool part 11 that is used in textile processing in a textile machine, and to a method for producing same. The textile machine part tool 11 has a tool core 16 made of a core material that is coated, at least in part, with a wear-resistant coating. The wear-resistant coating 17 is applied to a core surface 18 that has a first microstructure 19. The first microstructure 19 is preferably created using electrochemical etching in the core surface 18. The wear-resistant coating 17 applied thereto is preferably applied, at least in sections, immediately to the cores surface 18 having the first microstructure 19 using electrochemical deposition and has a layer thickness of a maximum of 20 μm.

REFERENCE LIST

[0055] 10 Eye needle [0056] 11 Textile machine tool part [0057] 12 Working section [0058] 13 Eye [0059] 14 Holding section [0060] 15 Needle holder [0061] 16 Tool core [0062] 17 Wear-resistant coating [0063] 18 Core surface [0064] 19 First microstructure [0065] 20 First depression [0066] 21 First elevation [0067] 22 Second microstructure [0068] 23 Second depression [0069] 24 Second elevation [0070] 25 Edge zone [0071] 26 Edge [0072] d Layer thickness [0073] Ri Radius [0074] R1 First radius [0075] R2 Second radius [0076] R3 Third radius [0077] R4 Fourth radius [0078] S1 First method step [0079] S2 Second method step [0080] S3 Third method step [0081] z Interval