SU1763162A1 - Abrasive cutting circle - Google Patents

Abstract

Use: for machining fragile materials. Due to the presence in the body of radial grooves made at a depth of (0.5-0.7) t, where t is the thickness of the body, with a distance between the grooves

Description

The invention relates to the machining of hard brittle materials and can be used in the manufacture of tools intended primarily for the separation into plates of single crystals of semiconductor and dielectric materials.

The aim of the invention is to increase the wear resistance of the wheel.

FIG. 1 shows a section of the cutting edge and the circle body; in fig. 2 is a side view of the housing with grooves formed therein; in fig. 3 is a top view of the housing from the side of the grooves filled with nickel and diamond grains. In the drawings, the following symbols are accepted: 1 - metal case; 2 - galvanic nickel; 3 - diamond grains.

The quantitative parameters included in the claims have the following rationales.

The grain size of the diamond powder in the composite, which fills the volume of the grooves, must be chosen in the range of 60-100 µm. If the grit of the diamond powder is less than 60 microns, then other properties of the composite

virtually no effect on the dynamics of the cutting edge, therefore the wear resistance of the wheels does not increase. The grain size of the diamond powder should not be greater than 120 microns, since in this case large diamond grains can stand for the dimensions of the circle body, taking part in the process. In this case, the insufficient surface quality of the cut plates excludes the possibility of using circles after a rather short period of operation.

The volume content of the diamond powder in the composite should be 11-20%, i.e. the volume ratio of nickel and diamond powder should be within (8: 1) - (41). If the volume content of diamond powder is less than 11%, other properties of the composite do not appear, which reduces the durability of the wheel. When the content of diamond powder is more than 20%, the composite becomes brittle and quickly collapses under the influence of cyclic loads.

The height of the groove in the radial direction should not be less than the height of the abra (L

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vj

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zivosoderzhёgo layer. Otherwise, taking into account the actual dimensions of the cutting edges used in practice, the elastic properties of the wheel will not appear, and its wear resistance will not increase.

Limitations imposed on the width of the grooves are due to the fact that when the width of the grooves is more than 16t (where t is the thickness of the circle body), the rigidity of the housing decreases to such a level that the required geometry of the cut plates cannot be ensured. With a groove width of less than 9t, a noticeable deterioration in the quality of the cut plates is observed, which practically does not allow the use of circles to obtain precision blanks.

It is advisable to make the body of a circle from cold-rolled corrosion-resistant metal with a breaking strength of at least 150 kg / mm2. Only cold rolling technology produces a sheet metal with a high-quality surface, uniform structure and sufficient strength. The requirement of corrosion resistance is explained by the possibility of using quite aggressive coolants in the process of working circles.

Taking into account the small thickness of the wheel body and the relatively large local cutting forces, the body must be stretched with considerable tension in order to provide the necessary rigidity of the cutting edge. The minimum value of breaking strength, ensuring the fulfillment of the above conditions, must be at least 1540 kg / mm2. Otherwise, breaks in the metal of the hull are observed after a brief use of the wheel.

Examples of the use of circles.

Monocrystalline silicon ingots with a diameter of 76 mm and germanium with a diameter of 40 mm were cut into plates with a thickness of 0.5 mm. The cutting was carried out using AKVR 422x152 circles with geometrical dimensions corresponding to GOST 26004- 88. The circle was installed on the drum of the machine. Diamond-6 and was driven at a rotational speed of 2000 rpm. A working feed of 30 mm / min was set. The cutting plates were monitored for compliance with the technical requirements for the depth of the broken layer, surface roughness and non-flatness. The number of cut plates that, according to their geometry, satisfied the requirements of technical conditions, was taken to be the wear resistance of the wheel. The circle was considered to be out of operation in the case when a stable marriage of the cut plates with respect to geometry was observed, which could not be eliminated by correcting the cutting edge and retaining the body.

Quantitative characteristics of examples of using circles are given in the table. The results indicate that the proposed circles have a higher wear resistance while maintaining the high quality of the cut plates.

Claims (1)

Claims An abrasive cutting disc made in the form of an annular metal disc, on the end surfaces of which, in grooves arranged in a checkerboard depth exceeding half the thickness of the disc, is placed an abrasive containing cutting layer, characterized in that The abrasive-containing layer is made in the form of galvanically deposited nickel with diamond powder with a grain size of 60-100 μm with a volume ratio of nickel and powder (4-8): 1, respectively, with the height of the groove in ialnom direction is not less than the height abrazivosoderzha- conductive layer, while its width is (9-16) t, where t - the thickness of the housing. Examples of using circles when cutting ingots NNV-NV4 x h N  ; , - xO О   h h - noOO.OWV - lOQgO-QcSQ Pu "2 I (2-y) t J - noOO.OWV - lOQgO-QcSQ.