GB2044146A - Manufacture of diamond and like tools - Google Patents

Abstract

A method of manufacture of diamond or similar tools e.g. for grinding wheel dressing purposes, comprises providing elements (1) each consisting of a small body (10) of matrix material and of standardised shape having one or more diamond or crystals (11) of super hard material held therein, one or more of the elements (1) being secured in a tool head (20) such as in a main matrix (21) of the latter. The elements (1) may be arranged in rows or layers in the tool head (20) for successive use as a layer is worn away. Sintered matrix material of each element (1) preferably has a content of titanium, niobium, tantalum or similar metal to provide an effective bonding or welding action with the or each diamond or crystal (11) received by the body (10) whilst the material of a main matrix (21) when employed may be bronze based or of metal filled ceramic or plastic material for providing good thermal conductivity from the elements (1) therein. <IMAGE>

Description

SPECIFICATION Manufacture of diamond or like tools The object of this invention is to provide an improved method of manufacture of diamond or similar tools e.g. for grinding wheel dressing purposes and also the resulting tools more particularly where the latter are of the kind in which the operative surface or surfaces of the tool carry one or more diamonds or similar crystals of super hard material such as cubic boron nitride or tungsten carbide set in a suitable matrix.

The invention relates more especially to the manufacture of such tools of the consumable or 'throw away' type which are discarded after use i.e.

without re-setting.

A particular object of the invention is to enable the manufacture of the tools to be carried out in a standardised manner in the interests of economic quantity production in which high quality can be maintained. This and other practical advantages will be apparent from the following disclosure.

According to this invention the method of manufacture of diamond or similar tools is characterised by providing one or more elements consisting, or each consisting of, one or more diamonds or similar crystals of super hard material set in a small body of matrix material and of standardised shape, and securing said element or elements in or on a mounting member or a tool head so as to provide a diamond or like tool.

In practice the procedure is as follows, reference being had to the accompanying drawings in which: Figures 1 and 2 are a perspective view and sectional elevation respectively of a typical standard element, Figures 3 and 4 are diagrammatic elevations each showing typical layer arrangements of the elements in a diamond tool, Figures 5to 7 are side elevations each showing a different type of diamond tool in accordance with the invention, and Figures 8 and 9 are sectional elevations of further developements.

Like parts are referred to by the same or similar reference numeral designation throughout the drawings.

The body or plug 10 of matrix material or each element 1 receiving a diamond 11 or more than one of the latter is of standardised shape such as the cylindrical form shown in Figures 1 and 2. Each such body 10 is a miniature form i.e. of sufficient size to receive a diamond or diamonds 11 and may be of the order of two or three millimetres in diameter although its dimensions may vary according to requirements. The diamond or diamonds 11 may be initially wholly embedded in the body 10 or the diamond or leading diamond 11 may protrude therefrom as shown.

As indicated in Figures 3 and 4 the elements 1 can be arranged and secured in rows or layers in a main body 21 of matrix material in a head 20 of a diamond tool 2, the elements 1 of each layer being either aligned (Figure 3) or staggered (Figure 4) or in any other suitable arrangement whereby as one layer is worn away the diamonds 11 of a further layer can be brought into use, e.g. for grinding wheel dressing purposes. The main body 21 of matrix material is shown received in a socketed steel head 20 of the tool but the body 21 may serve solely as the tool head.

By such an arrangement and owing to the small size of each body 10, the latter can consist of high quality matrix material having a content (e.g. 10%) of titanium, niobium or tantalum or similar metal so as to have an effective chemical bonding or welding action about a diamond 11 received by the body 10.

Thus not only is the diamond 11 firmly held in the body 10 but good contact for thermal conductivity is provided whilst the bodies 10 can be readily produced in quantity by sintering to obtain uniform density of the bonded matrix material of the body 10.

Furthermore, and owing to their small size, sintering of the elements 1 can be effectively carried out under controlled atmospheric or vacuum conditions with little or no likelihood of the diamond or diamonds 11 being adversely affected by the raised temperature during the sintering operation.

A further practical advantage of the invention is that the firm chemical bond between the high quality matrix material of the element 1 and diamond 11 results in the latter being held in place even when very considerably worn so that loss or fall out of a diamond or diamonds from the tool under conditions of use is avoided or very largely minimised.

As indicated in Figures 3 and 4 and also in Figures 5 to 7 the standardised elements 1 can be arranged in various formations according to requirements and with quick and accurate positive positioning of the diamonds 11 in the tool head 2. Thus the problem of "floating" diamonds occurring in the tool head during manufacture can be avoided and which has hitherto occurred especially when hot pressed sintering techniques are employed.

The main body 21 of matrix material in the tool head 20 or providing the latter can be of lower quality material e.g. of the bronze based type or may consist of ceramic or plastic material (e.g. metal filled plastic material) capable of firmly holding the elements 1 in position in the tool head 2 and at the same time providing a high degree of thermal conductivity from the elements 1 and diamonds 11 therein. Thus the main body 21 serves as a heat sink for conduction of head from the elements 1.

The thermal conductivity provided by the main body 21 of matrix material in conjunction with that provided by the firm bond between the matrix material of each element body 10 and diamond 11 located therein minimises the likelihood of thermal degradation of the diamond 11 under operating conditions.

The matrix material of each element body 10 andlorofthe main body 21 may consist of fully sintered tungsten carbide.

The invention has particular practical application to consumable grinding wheel dressing tools and thus in the case of the tool 2 shown in Figure 5 a successive layer of diamonds 11 in their bodies 10 in the matrix material 21 of the tool head 20 are brought into operation as a preceding layer is worn away. Alternatively and as shown in Figure 6 a fresh diamond 11 in its body 10 can be brought to the operative position by rotation of the circular head 20 of matrix material until all the diamonds 11 have been used. In the further arrangement shown in Figure 7 a series of elements 1 are arranged end to end in a head 20 of appropriate form so that a single diamond point is presented for use at any time. After the leading diamond has become worn it is followed by the next diamond 11 in its body 10 on corresponding shortening of the head 20.

Referring to Figure 8 a development is shown in which each element 100 is of larger form incorporating one or more rows of diamonds 11. The thickness of the element 100 is preferably substantially the same as the average axial length of the diamonds 11 so that the mass of high quality matrix material can be kept to a minimum in the interests of economy and facilitating the sintering of the elements and also avoiding or minimising thermal degradation of the diamonds 11 during the sintering operation.

A plurality of elements 100 of square form in face view are shown embedded in layer formation in a head 200 of a dressing tool 2 consisting of lower grade matrix material 210, the head being of corresponding square form on a shank 22. Also as shown the diamonds 11 of one element 100 are staggered with respect to those of an adjacent element or elements 1 Ccr.

However, the elements 100 may be of rectangular, circular or other form in face view according to tool design requirements.

In a further example shown in Figure 9 an element 110 of standardised form holding a diamond 11 and of high quality matrix material is received in a recess 223 in the leading end of the head 220 of a dressing tool shank 222 and is secured therein by temperature resistaiit adhesive or bonding material or by a press fit o r sh ri n k fit.

In this arrangement the rear end of the diamond 11 is exposed in a chamber 224 in the head 220 of the tool shank 222 and which communicates with a bore 225 along the latter so that coolant such as carbon dioxide gas can be directly applied to the diamond 11, e.g. by a tubular needle 226 in obtaining effective cooling thereof especially having regard to the high degree of thermal conductivity of the diamond. Such a cooling arrangement is the subject of our prior patents Nos. 1,546,589 and 1,550,430.

The tool head 220 and shank 222 can be of hardened steel for re-use of the head and shank can be of the usual mild steel which is discarded after use.

As will be appreciated and by means of the invention, the standardised elements 1, 100 or 110 can be incorporated in a wide variety of diamond tools for different requirements and which shanks 22 or 222 or varying form.

The invention includes within its scope not only the method of diamond or like tool manufacture as herein defined and described, but also diamond or similartoolswhen produced by the method.

The invention further includes standardised elements as herein described for use in the method of diamond or like tool manufacture and in the resulting tools.

Claims (14)

1. Method of manufacture of diamond or similar tools characterised by providing one or more elements consisting, or each consisting of, one or more diamonds or similar crystals of super hard material set in a small body of matrix material and of standardised shape, and securing said element or elements in or on a mounting member or tool head so as to provide a diamond or like tool.

2. Method of manufacture of diamond or similar tools according to claim 1 wherein the body of the or each element is of sintered matrix material.

3. Method of manufacture of diamond or similar tools according to claim 2 wherein the sintered matrix material of the or each element body has content of titanium, niobium, tantalum or other suitable metal to provide a bonding or welding action about the or each diamond or similar crystal of super hard material set in the element.

4. Method of manufacture of diamond or similar tools according to claim 1,2 or 3 wherein the element or elements is or are set in a main body of matrix material of the tool head.

5. Method of manufacture of diamond or similr tools according to claim 4 wherein the main body of matrix material is received by a socket of the tool head or provides the latter.

6. Method of manufacture of diamond or similar tools according to claim 4 or 5 wherein the matrix material of the main body is bronze based or is of ceramic or plastic material such as metal filled plastic material in order to firmly hold the element or elements and provide good thermal conductivity therefrom.

7. Method of manufacture of diamond or similar tools according to any of claims 4 to 6 wherein a plurality of the elements are arranged and secured in rows or layers in the main body of matrix material.

8. Method of manufacture of diamond or similar tools according to claim 7 wherein the elements of the rows or layers thereof are aligned or arranged in stagggered formation.

9. Method of manufacture of diamond or similar tools according to any of claims 1 to 3 wherein the element or elements is or are received or contained in a metal head of the tool;

10. Method of manufacture of diamond or similartools substantially as herein described with reference to any of the several embodiments of the tools shown in the accompanying drawings.

11. Diamond orsimilartoolswhen manufactured by the method according to any of claims 1 to 10.

12. Diamond or similar tools substantially as herein described with reference to the several embodiments thereof shown in the accompanying drawings.

13. Elements each consisting of one or more diamonds or similar crystals or super hard material set in a small body of matrix material for use in the manufacture of diamond or similar tools according to any of claims 1 to 10 and in tools produced by said method.

14. Elements for use in the manufacture of diamond or similar tools according to any of claims 1 to 10 and in tools produced by said method wherein the elements are substantially as herein described with reference to the accompanying drawings.