RU2308357C1 - End milling cutter with diamond segments for working blanks of carbon or carbon-graphite materials - Google Patents

Abstract

FIELD: mechanical working of brittle materials such as carbon or carbon-graphite materials.

SUBSTANCE: milling cutter includes disc having peripheral inserts with diamond segments forming diamond-bearing layer; impeller secured to back side of disc; inclined openings formed in disc under said inserts and passing to ducts between blades of impeller. In order to improve efficiency of removing dust-air mixture milling cutter is provided with arc-shaped blades mounted on disc at side of inserts behind inclined openings along direction of working rotation of milling cutter.

EFFECT: improved efficiency of removing dust-air mixture.

4 cl, 4 dwg

Description

The invention relates to devices for the machining of products from brittle artificial and natural materials, mainly carbon or carbon-graphite, and can find application in electrode plants, as well as in factories for the processing of coal and carbon-graphite products.

A device for processing brittle materials is known, which we have chosen as a prototype (Ukrainian patent No. 53754, IPC B28D 7/02, B24B 55/04, 55/06, from 28.04.00, publ. 02.17.03), in which the cutting tool is made in the form of a disk, on the periphery of which there are inserts with diamond segments forming a diamondiferous layer. An impeller is attached to the back of the disk. In the disk under the inserts there are made inclined holes passing into the channels between the impeller blades.

When processing workpieces with a known device, the removable layer in the form of a dust-air mixture is carried away into the dust collector casing due to the rarefaction created by the impeller, inclined openings in the tool disk and inclined diamond segments. However, the inclined holes of the flat disk do not allow to effectively capture the dusty air mixture from the space between the workpiece and the tool. In addition, the diamond layer of the known device wears unevenly over the entire working surface of the inserts. The most loaded part of the insert is closer to the center of rotation of the device, therefore, in this place the diamondiferous layer is removed intensively to the insert body, and at the periphery it remains in a significant amount. Such an insert does not have the necessary cutting ability, and further processing of the workpieces without restoring the diamond layer is already impossible.

The basis of the invention is the task of increasing the efficiency of removing the dusty air mixture from the processing zone of the workpieces and preserving the cutting ability of the tool until the diamond layer of the inserts is completely worn out due to the new construction elements.

The problem is solved in that the diamond end mill for processing workpieces made of carbon or carbon-graphite materials, including a disk with inserts located on the periphery with diamond segments forming a diamond layer, an impeller attached to the back of the disk, inclined holes made in the disk under the inserts and passing into the channels between the impeller blades, according to the invention contains arcuate blades mounted on the disk from the side of the inserts behind the inclined holes in the direction of work bringing rotation of the cutter and covering these holes. In this case, the arcuate blades are made with an inclination at an angle corresponding to the angle of inclination of the holes, the cutter disk and the inserts are made with the possibility of turning the inserts, which is realized after the diamond layer is worn on one side, and their subsequent fixation. The diamondiferous layer of the inserts contains diamonds with a grain size of 630/500, a concentration of 20-60% and is made on a copper-tin binder doped with titanium hydride.

The introduction into the design of a diamond mill of arcuate blades, covering inclined holes, and placing them on the disk from the side of the inserts behind the inclined holes (in the direction of the working rotation of the cutter) will increase the efficiency of capture of the dust-air mixture from the processing zone. Due to the inclination of the blades at an angle corresponding to the angle of inclination of the holes, the dust-air mixture forms laminar flows that enter the interscapular space and then into the dust collector casing. This increases the cooling efficiency of the cutting zone, which helps to reduce the wear of the diamond layer and, as a result, increase the cutting ability of the tool.

The implementation of the disk cutters and inserts with the possibility of turning the inserts and their subsequent fixation will save the cutting ability of the cutter to the complete wear of the diamond layer. During the operation of the cutter, the diamondiferous layer is removed intensively closer to the center of rotation of the cutter, and remains significant in the periphery. After the part of the inserts is turned 180 °, the surface of the diamond layer is “aligned” over the entire cutting part of the cutter and it becomes possible to process the workpieces with the same inserts. Thus, the cutting ability of the cutter is maintained until the diamond layer is completely worn out.

When processing carbon and carbon-graphite workpieces with the inventive cutter, due to the use of inserts with a diamond-bearing layer on a copper-tin binder doped with titanium hydride in its design, intensive opening of diamond grains occurs. Between the binder and the workpiece surface to be machined, a gap is formed necessary to remove the material being removed, but at the same time the diamond grains are firmly held in the binder. The part of the grains protruding from the ligament is intensively cooled by a stream of air passing through the formed gaps.

The grain size of 630/500 diamonds and the concentration of diamond grains of 20 ... 60% provide a gap of 0.2-0.3 mm between the binder and diamond grain, sufficient for free cutting of carbon or carbon graphite material and contributing to the most complete removal of material from the cutting zone, with This eliminates the “salting” of the surface of the diamondiferous layer without the use of wetting and cooling liquids. The concentration of diamond grains of 20-60% is optimal, since with a decrease in concentration of less than 20% the cutting ability of the cutter decreases, and with an increase in concentration of more than 60%, the free space between the grains of diamonds decreases, this leads to “salting” of the surface of the diamondiferous layer.

As follows from the foregoing, the claimed combination of features is necessary and sufficient to achieve the task.

The essence of the invention is illustrated by drawings, where figure 1 shows a General view of the cutter and section AA; figure 2 shows the characteristic wear of the diamondiferous layer of the insert; figure 3 shows the insert with a diamond layer after a turn, figure 4 shows an insert with a completely worn diamond layer.

The inventive diamond end mill contains a disk 1, on the periphery of which there are inserts 2 with diamond segments 3, forming a diamondiferous layer. An impeller 4 is attached to the rear side of the disk 1, inclined holes 5 are made in the disk 1 under the inserts 2. Behind the inclined holes 5 are arcuate blades 6 covering these holes. Arcuate blades 6 are inclined to the disk 1 at an angle α corresponding to the angle of inclination of the holes 5. The inserts 2 are attached to the disk 1 by bolts 7. The working rotation of the cutter is carried out in the direction of arrow 8.

The mill works as follows.

When the milling cutter rotates in the direction of arrow 8 at a speed corresponding to the required workpiece processing mode, the material to be removed located between the surface of the disk 1 and the workpiece (not shown) is captured by arcuate blades 6 and, in the form of a dust-air mixture, is directed through the inclined holes 5 into the interscapular channels of the impeller 4 and further into the dust collector housing (not shown).

The work of the cutter when processing workpieces from carbon or carbon-graphite materials is possible in two modes, namely, in the mode of initial opening of diamond grains of the diamond-bearing layer of inserts and in the mode of processing workpieces with a cutter with opened diamond grains.

In the process of milling cutters in the mode of opening diamond grains, a carbon blank is used as an abrasive. This is possible because abrasive components, such as silicon carbide, are present in the calcined carbon blanks, and the workpiece, when special cutting conditions are established, serves as an abrasive tool. For this, the workpiece feed is set to 50-100 mm / min, the cutting depth is 5-10 mm, and the cutting speed is 25-40 m / s. During the opening of diamond grains, the amount of energy consumed by the machine is reduced, then the amount of consumed electricity is stabilized, which characterizes the end of the process of opening the diamond grains.

After the opening operation, the diamond grains of the inserts are exposed sufficiently to use the cutter in the workpiece processing mode. In this mode, the workpiece feed is increased to 630-1000 mm / min, the cutting depth is set depending on the geometric dimensions of the cutting part of the cutter and the drive power of the cutter. The cutting speed is set within 40-60 m / s. During the operation of the diamond end mill, the diamond layer 3 of the inserts 2 wears out closer to the center of its rotation, and after a while it is completely removed to the body of the insert 2, and remains in a significant volume at the periphery (see Fig. 2). After that, the operation of the machine with the milling cutter installed on it is temporarily stopped, part of the inserts 2, for example, every second one, after removing the fixing bolts 7, are rotated 180 ° and re-fixed on the disk 1 with bolts 7 (see Fig. 3). As a result, the diamondiferous layer is “aligned” over the entire cutting part of the cutter. Then continue processing the workpiece with a mill with the same inserts 2 until the diamond layer 3 is completely worn (see figure 4).

The use of the inventive diamond end mill will allow:

- increase the efficiency of dust removal from the treatment area by 10%, which will lead to a reduction in dust in the workplace;

- to save the cutting ability of the cutter until the diamond layer is completely worn out, which will lead to an increase in the volume of workpieces processed by the same inserts by 40%.

In addition, since the preliminary preparation of the cutter for work, namely, the opening of the diamond layer is carried out directly by the workpiece, the need for a special grinding machine is eliminated, which is economically feasible.

The inventive cutter is made and tested in the machining workshop of OJSC "Ukrgrafit".

Claims (4)

1. Diamond end mill for processing workpieces of carbon or carbon-graphite materials, including a disk with peripheral inserts with diamond segments forming the diamond layer, an impeller attached to the back of the disk, and inclined holes made in the disk under the inserts and passing into the channels between the impeller blades, characterized in that it is equipped with arcuate blades mounted on the disk from the side of the inserts behind the inclined holes in the direction of the working rotation of the cutter and yvayuschimi these holes. 2. The mill according to claim 1, characterized in that the arcuate blades are inclined to the disk, at an angle corresponding to the angle of inclination of the holes. 3. The milling cutter according to claim 1, characterized in that the milling cutter disk and the insert are capable of turning the inserts after wear of the diamond layer on one side and their subsequent fixation. 4. The cutter according to claim 1, characterized in that the diamondiferous layer of the inserts contains diamonds with a grain size of 630/500, a concentration of 20-60% and is made on a copper-tin binder doped with titanium hydride.

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