WO2004094111A1

WO2004094111A1 - Method for the production of an abrasive tool

Info

Publication number: WO2004094111A1
Application number: PCT/CH2004/000245
Authority: WO
Inventors: Benno Zigerlig; Gregor Burkhard; Manfred Kiser
Original assignee: Empa Eidgenössische Materialprüfungs- Und Forschungsanstalt; Eidgenössische Technische Hochschule Zürich
Priority date: 2003-04-24
Filing date: 2004-04-23
Publication date: 2004-11-04

Abstract

Disclosed is a method for applying grains of hard material onto a tool surface in a predefined pattern. According to said method, the surface is provided with a non-conducting masking layer (2) that comprises empty spots (20). The grains of hard material (4) are deposited into said empty spots (20) by means of a galvanic process, especially pulse plating, whereupon the surface is provided with a reinforcement layer (5).

Description

Process for manufacturing eiaes ahrasi'yeπ, factory ags

Technical field

The invention relates to a method for producing an abrasive tool and an abrasive tool according to the preamble of claims 1 and 14, respectively.

State of the art

The economic design of a grinding process is largely dependent on the achievable stock removal rate. However, high stock removal rates increase the demands on grinding tools. On the one hand, these tools must have high grain protrusions and spacings so that both chips and cooling lubricant have enough space in the contact zone between the grinding tool and the workpiece. On the other hand, these tools must have larger grain densities or more robust, larger grains at highly stressed areas such as edges and exposed profile tips.

Various methods are therefore known from the prior art for providing abrasive tools with hard material grains. A galvanic process in which an abrasive layer consisting of a nickel layer and _. Hard material grains applied to a grinding tool is known for example from CH-A-644'295. Draw galvanically bonded abrasive tools by their resistance and high achievable work ^¬ convincing accuracy of. However, a disadvantage is that the possible answer ^¬ th to influence the grain density and distribution very be ^¬ are limited.

From US-A-6'039 '641, a manufacturing method is known, used wel ^¬ ches a mask to define the diamond grains to be placed on a support surface. The diamond grains are soldered into the carrier layer for fixation.

EP-A-1'208'945 suggests sticking hard material grains to the tool surface. For this purpose, adhesive droplets are applied to the surface of the tool in a predetermined pattern and the surface is sprinkled with the hard material grains. Only those grains that come into contact with a drop of glue stick. The non-sticky grains are removed again. This makes it possible to produce a tool with a highly precise distribution of the hard material grains.

These two last-mentioned methods have the disadvantage that, in comparison to the electroplated tools, a thermal process is required which can lead to component distortion and damage to the hard material grains as a result of thermal stress and chemical interface reactions.

Presentation of the invention

It is therefore an object of the invention to provide an economical method for producing a powerful abrasive tool with a structured abrasive coating. It is another object of the invention to provide an abrasive tool that is powerful, structured abrasive has lag and is economical to produce.

These tasks are solved by a method and a device with the features of claims 1 and 1, respectively.

In the method according to the invention, the structured abrasive coating is achieved in that an electrically non-conductive mask layer is applied to the surface of the tool and the vacancies of the mask are covered with hard material grains, in particular with super hard material grains, in one or more galvanic process steps. A reinforcing layer is then preferably applied.

Depending on the choice of the size of the vacancies, single grain separations or clusters of hard material grains can be achieved in the vacancies.

Pulse-plating is preferably used in the galvanic deposition, so that a uniform deposition can also be achieved on curved surfaces.

In a preferred variant of the method, the reinforcement layer is used to deposit hard material grains, which, however, have a diameter many times smaller than the hard material grains filled in the vacancies. This reinforces this layer and supports the hard grains.

In a further preferred variant of the method, hard material grains with different diameters can be applied to the tool surface with a minimal number of process steps. For this purpose, the mask layer is provided with vacancies of different sizes and the galvanic deposition is divided into several sub-steps, with each sub-step Hard grains of a kind are to be separated, starting with the kind with the largest grain diameter. This method has the advantage that the mask layer has to be applied and structured only once and that the tool does not have to be treated between the individual galvanic sub-process steps.

Further advantageous variants of the method and advantageous embodiments emerge from the dependent patent claims.

Brief description of the drawings

The subject matter of the invention is explained below on the basis of preferred exemplary embodiments which are illustrated in the accompanying drawings. Show it:

Figures la to If a cross section through a schematically illustrated surface of a tool in a first to fifth manufacturing step

Figure 2a is a top view of a tool after the second manufacturing step; FIG. 2b shows an enlarged detail according to FIG. 2a;

Figure 3a is a top view of a tool after the fifth manufacturing step;

FIG. 3b shows an enlarged detail after the fourth manufacturing step;

Figure 4a shows a cross section through a schematically shown Surface of a tool with a chemically applied further layer; FIG. 4b shows a cross section through a schematically represented surface of a tool with an electrolytically applied further layer;

FIG. 5a shows a cross section through a schematically represented surface of a tool according to a second variant of the method;

Figure 5b shows the surface according to a third variant of the method;

5c shows the surface with a hard material layer as a mask layer;

Figure 6 shows the surface with armor of the other layer and

Figures 7a to 7d a schematically illustrated surface of a tool in a first to fourth manufacturing step according to a further variant of the invention.

Ways of Carrying Out the Invention

A preferred variant of the method is shown in Figures la to lf. In a first step according to FIG. 1 a, a mask layer 2 is applied to a base body 1 of an abrasive tool to be produced. This mask layer 2 is preferably a lacquer or color layer. In a later process step, as is the case here, metal ions, with or without the aid of a suitable external power source or a chemical electron donor, are extracted from aqueous deposited solution, hereinafter referred to as a galvanic process, the layer 2 must be electrically non-conductive.

It is preferably applied homogeneously and then structured. This takes place in the second step according to FIG. Ib. The removal is preferably carried out by means of a suitable laser, for example an Nd.Yag laser, an excimer laser or an argon laser. Marking laser machines are known on the market which materials can remove in any pattern and in the smallest form. FIGS. 2a and 2b show a surface of the tool provided with the mask layer 2.

As shown in FIG. 1c, the layer 2 now forms a mask with empty spaces 20. In a third step according to FIG. 1d, the tool with its mask layer 2 is subjected to a galvanic coating process of a known type. This means that the exposed sections of the surfaces of the workpiece are activated and nickel or another suitable material is deposited together with hard material grains 4, in particular super hard material grains such as diamonds or CBN. Nickel adheres to the free surfaces and forms a carrier layer 3. In each empty space 20 there is only one hard material grain 4. However, it is also possible to separate grain clusters. Since nickel and the hard material grains 4 do not adhere to the mask layer 2, these areas remain free. The galvanic coating process, i.e. the nickel plating, preferably takes place in a sulfate bath or a sulfamate bath.

The mask layer 2 is removed in a fourth step according to FIG. Which of the known methods of removal is used depends on the material used. In a fifth step according to FIG. 1f, the structural height is increased and thus the anchoring of the hard material grains 4 is further reinforced by applying a further layer, hereinafter called reinforcing layer 5, to the entire surface of the tool that is now exposed. Again, this is preferably a nickel layer. The result with a single grain allocation is shown using an example in FIGS. 3a and 3b.

This reinforcing layer 5 can be applied chemically or electrochemically. The chemical method has the advantage that regardless of the profile geometry, more uniform layer thicknesses are achieved. If the electrochemical method is used, a sulfamate bath or a sulfate gloss bath is preferably used again. A chemical nickel bath is preferably used in the chemical method. Figure 4a shows the result of a chemical process, Figure 4b of an electrochemical.

The backing layer 3 and the reinforcement slide 5 together, depending on the application and the type of grain used, usually have a thickness of 40% to 60% of the nominal grain size of the hard material grains 4. The thickness of the mask layer 2 depends on the nominal grain size of the hard material grains to be applied. The thickness of the mask layer 2 is typically 10% to 100% of the nominal grain size. Good results were achieved in the range of 20% - 60%. The diameter of the vacancies 20 also depend on the nominal size of the hard material grains 4. If a single grain separation is to be achieved, the vacancies 20 should have a size which is only slightly larger than the nominal diameter of the grains. In the case of grain clusters, they are correspondingly larger. Typical diameters of the vacancies 20 are 1 μm to 1 mm. In this method, nickel is preferably used both for the carrier layer 3 and for the reinforcing layer 5. However, other suitable materials can also be used.

As a mask layer 2 can be used instead of a paint walls ^¬ res electrically non-conductive material, such as a hard material layer, a dry or wet resist, use. The mask layer 2 can be structured as described above after application to the base body 1. However, it can also be structured during application, for example by spraying it on through a mask. Furthermore, it can also be structured beforehand and applied, for example, in the form of a film or a perforated plate. If the layer is structured after application, this can be done instead of with a laser. also take place thermally, mechanically or chemically.

It is also possible to use a hard material layer consisting of several partial layers. In particular, it is possible to apply an electrically non-conductive, insulating partial layer and an electrically conductive partial layer, the latter making it easier to overgrow the reinforcing layer. If a hard material layer is used, it is not necessary, depending on the area of application, to provide the entire exposed surface of the tool with the reinforcing layer. It is sufficient if it is applied in the area of the hard material grains, in which case it can overgrow the hard material layer, as shown in FIG. 5c.

The structured carrier layer and the reinforcement layer visibly consist of two different layers, which is also evident in the finished tool, more precisely in a cross section. of, can be determined.

In another variant of the process according to figure lf dispense with the fifth step, said egg already ^¬ ne support layer is placed in the desired final thickness up ^¬ 3 in this case, in the third step, together with the Hartstoffkδrnern. 4

In a further variant of the method, the structured mask layer 2 is not or only partially removed, but the reinforcement layer is applied over the mask layer 2, as shown in FIG. 5b. This variant is particularly suitable for relatively thin hard material layers.

In a further variant of the method, the reinforcement layer 5 is applied only over the carrier layer 3. This is shown in Figure 5a. After the mask layer 2 has been removed, this variant has a greater free space on the tool surface than the variant lf.

The hard material grains are preferably applied by means of suitable current modulation with the aid of alternating anodic or cathodic current switching and also current pauses / interruptions, hereinafter referred to as pulse plating. Pulse plating differs from the usual galvanic processes in that the electrical voltage is not applied constantly but in a pulsed manner. Increased voltage at the edges and unfavorable tool-electrode spacings can cause an uneven layer growth of the nickel layer. It has been shown that significantly more homogeneous support and reinforcement layers can be formed by pulsing the current. The pulse plating can be used for the application of the carrier and / or the reinforcing layer 3, 5. In a further variant of the method, shown in FIG. ₆ , further hard material grains 40 are applied when the reinforcing layer 5 is applied, but these have a diameter many times smaller than the hard material grains 4 of the carrier layer 3. This reinforces and reinforces the reinforcing layer 5 thus mechanically more resistant. This variant is preferably electrochemical.

In a further variant of the method, which is shown in FIGS. 7a to 7d, hard material grains 4, 4 'are applied in different sizes. For this purpose, the surface of the tool to be machined is provided with a structured mask layer 2 as described above. This mask layer 2 now has empty spaces 20, 21 of different sizes. In a next step, shown in FIG. 7c, hard material grains 4 of a first type, which have the largest or larger diameter, are first deposited. These hard material grains 4 of the first type can only accumulate in the larger empty spaces 20. The diameters of the smaller empty spaces 21 are too small for this. In a next step, hard granules 4 'of a second type, which now have a smaller diameter, are deposited in the second empty spaces 21. By selecting the separation parameters accordingly, it is possible to store the different hard material grains at different heights or at a common height.

The following steps correspond to the method steps 1d to 1f described above. Although only two different sizes of vacancies 20, 21 are shown in the figures, the method can also be carried out with more types of hard material grains 4, 4 'and vacancies 20, 21, as long as they start with the largest diameter and with the smallest diameter. water of the existing group of hard material grains to be applied. An advantage of this method is that only a single resist layer 2 is necessary and also the masking be ^¬ relationship, the spaces in a single process step can be applied. It is also advantageous that the galvanic deposition can be carried out in successive steps, so that the transport paths of the tools can be minimized during manufacture.

Although flat surfaces are shown here in the drawings, curved or differently shaped surfaces, in particular those with complicated geometries, can also be coated with the method according to the invention. For this purpose, the focus of the laser on the respective surface must be set in the second method step. This can be achieved by changing the position of the laser or, even more simply, by correspondingly moving the workpiece to be produced. It is also advantageous if pulse plating is used.

The reinforcing layer 5 and / or the carrier layer 3 can also be provided with different additives or alloy components, for example in order to increase the corrosion protection and the hardness.

If more than one hard material grains 4 are to be introduced per empty space 20, that is to say clusters are to be formed, 4 placeholders can also be separated together with the hard material grains. Such placeholders are, for example, glass balls, glass powder or graphite parts. This allows the grain density in the clusters to be controlled and / or the tribological properties to be changed. If desired, the placeholders can be removed afterwards using a suitable medium. be solved.

The method according to the invention enables simple and inexpensive production of a high-performance abrasive tool.

LIST OF REFERENCE NUMBERS

Base body mask layer Vacancies Vacancies Carrier layer Hard material grains Hard material grains Hard material grains Reinforcing layer

Claims

claims

1. A method for applying hard material grains to a tool surface in a predetermined pattern, the surface being provided with an electrically non-conductive mask layer (2) which has empty spaces (20), hard material grains (4) using a galvanic process step in the empty spaces ( 20) be deposited.

2. The method according to claim 1, wherein the surface is provided with a reinforcing layer (5).

3. The method according to claim 1 or 2, wherein the mask layer (2) is applied to the surface in the form of a uniform layer and the vacancies (20) by means of a laser, chemically, thermally or mechanically into the applied layer ( 2) be molded.

4. The method according to any one of claims 2 or 3, wherein pulse-plating is used to deposit the hard material grains (4) and / or to apply the reinforcing layer (5).

5. The method according to any one of claims 2 to 4, wherein the mask layer (2) is removed before application of the reinforcing layer (5).

6. The method according to any one of claims 2 to 5, wherein the mask layer (2) is at least partially overgrown by the reinforcing layer (5).

7. The method according to any one of claims 2 to 6, wherein for the deposition of the hard material grains (4) and the application of Reinforcement layer (5) two galvanic baths with different compositions can be used.

₈ . Method according to one of claims 1 to 1, wherein a paint, a lacquer or a hard material layer is used as the mask layer (2).

9. The method according to any one of claims 1 to 8, wherein the decision ^¬ From the grains of hard material (4) and / or is used as a reinforcing layer (5) nickel.

10. The method according to any one of claims 2 to 9, wherein the reinforcing layer (5) is applied galvanically.

11. The method according to claim 10, wherein together with the reinforcing layer (5) further hard material grains (40) are deposited, which have a many times smaller diameter than the hard material grains (4) deposited in the vacancies (20).

12. The method according to any one of claims 1 to 11, wherein the same mask layer (2) before deposition of the hard material grains (4, 4 ') is provided with vacancies (20, 21) with different diameters and wherein the galvanic deposition of the hard material grains (4, 4 ') is subdivided into several partial steps, hard particles (4) with the largest diameters being separated in a first partial step and hard particles (4') with the next following smaller diameters of the existing group of hard material particles to be applied being deposited in subsequent partial steps.

13. The method according to any one of claims 1 to 12, wherein the mask layer (2) in a thickness of 10% to 100%, preferably from 20% to 60% of the nominal size of the hard material grains (4) is applied.

14. Abrasive tool with a hard material coating, produced by the method according to one of claims 1 to 13, wherein the hard material grains (4) are arranged in a predetermined pattern, characterized in that the hard material grains (4) are applied galvanically.

15. Tool according to claim 14, wherein the hard material grains in a carrier layer (3) fixed and by a reinforcing layer

(5) are reinforced, the carrier layer (3) extending locally around individual hard material grains (4) or hard material grain clusters.

16. Tool according to claim 15, wherein the carrier layer and / or the reinforcing layer (3) consists of nickel.

17. Tool according to one of claims 14 to 16, characterized in that under the reinforcing layer (5) there is a mask layer (2), the mask of which corresponds to the pattern of the arranged hard material grains (4).