RU2541331C2 - Vibratory cutting with formation of elemental chips and vibratory cutter - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: this process comprises spinning of machined part, feed of cutter including moving cutting section, resilient elements and fixed section and it vibratory sine displacement at cutting forces acting at oscillating loop composed by cutter moving section, resilient elements and fixed section with the help of rolling elements. Two support rollers fitted in contact with cutter moving section are used as said rolling elements. Oscillating cutter includes body with cover and moving cutting section with insert, resilient elements and fixed section to make oscillating loop, and rolling elements. Note here that said resilient elements are arranged between cutter moving section and body on side opposite the cutting direction. Said rolling elements are composed of two support rollers arranged in contact with cutter moving section and between cutter moving section and body with cover.

EFFECT: higher precision and efficiency of cutting.

8 cl, 3 dwg

Description

The invention relates to the field of engineering, in particular to the processing by vibration cutting of materials, mainly hard to work steels, alloys, viscous non-ferrous metals, composite and other materials. The inventive method and device for its implementation provide crushing chips during the processing of any materials while ensuring high productivity and high quality of the processed surface, and without the use of additional sources and devices for creating vibration.

Vibratory cutting of metals provides reliable crushing of chips during processing of any material. This effect is widely used in technology.

However, to implement the known methods of vibrational cutting, additional energy sources are usually used to drive devices that provide oscillatory movement of the cutting tool: mechanical, electromechanical, hydraulic, magnetostrictive, etc.

The well-known "Method and device for the formation of crushed chips during processing of a rotating part" (US patent No. 5113728, application. 10/11/1990, publ. 05/19/1992), in accordance with which the thickness of the chip periodically varies from maximum to zero. Such a periodic change in thickness is achieved due to the impact of the vibrating in a certain way, depending on the angular position of the rotating workpiece, the cutting tool. In accordance with the invention, the vibration of the tool can be provided by various devices. In a specific embodiment, an electromechanical drive is used.

The disadvantage of this invention is the need for an additional energy source and rather complex devices for bringing the tool into oscillatory motion. The presence of a rigid kinematic connection between the cutter and the oscillation generator leads to a decrease in cutting speed, tool life and accuracy of the workpiece.

Known methods of vibration cutting without the use of an additional energy source, in which the vibrational movement (vibration) of the cutter is carried out due to the action of cutting forces and elastic elements included in the vibrational circuit of the vibration cutter, see, for example, patents RU 2281187, RU 2356700. One of the first The sources of information in which such a method is described is the international application “Method and Vibratory Cutter for Processing Hard-Working Steels, Alloys, Viscous Non-Ferrous Metals and Composite Materials” (International Application No. PCT / IL2003 / 000232, Pub. No. WO / 2003/086688). The specified source of information is selected as a prototype for the method of vibration cutting and for a vibration cutter.

The prototype method includes the following steps:

- rotation of the workpiece relative to the axis of rotation;

- translational movement of the cutter when feeding;

- the oscillatory movement of the movable part of the cutter under the action of an oscillating circuit that closes the movable oscillating cutting part of the cutter through a set of elastic elements to the fixed part (cutter body).

Moreover, under the action of cutting forces on the oscillatory circuit, the trajectory of the positions of the tip of the cutter has a sinusoidal shape with different amplitude A of vibrations and height h of microroughnesses. Parameters A and h have the ability to adjust provided by elastic elements of different stiffness included in the oscillatory circuit of the cutter.

The prototype vibrating cutter comprises a housing (stationary working part), a housing cover, a movable (oscillating) part with one or more removable cutting plates, and a set of elastic elements connecting the movable part of the cutter with the housing and cover with the formation of an oscillating circuit. In this case, the movable part of the cutter is mounted with the possibility of rotation under the action of constituent cutting forces arising during processing on an axis fixed between the body and the cover.

However, the method and cutter selected as a prototype do not provide the necessary processing accuracy. Under the influence of considerable efforts, in particular as a result of the action of negative (directed against the direction of movement of the cutter) pulses, spontaneous “pushing” of the cutter from the axis of the workpiece occurs. At very high loads, the moving part of the cutter can even jam, and the cutter in such conditions will not work as a vibration, but as an ordinary one.

In addition, in the prototype, the chips are in contact with the front surface of the cutting insert for a fairly long time, which leads to overheating of the cutting part and premature failure.

The objective of the present invention is to provide a method of vibration cutting and vibration cutter without the use of additional energy sources, providing high precision processing with significant performance, as well as increased tool life due to the exclusion of its heating.

This problem is solved due to the fact that in the method of vibrational cutting with the formation of elemental shavings, providing for the rotation of the workpiece, the translational movement of the cutter made with a movable cutting part, elastic elements and a fixed part, providing oscillatory sinusoidal movement of the moving cutting part of the cutter under the action of forces cutting acting on the oscillating circuit formed by the moving part of the cutter, the elastic elements and the fixed part using elements s rolling according to the invention, as the rolling elements are used two support rollers arranged in contact with the movable part of the tool.

The above problem is also solved due to the fact that in the vibrating cutter containing the housing with the cover and the movable part with the cutting plate, a set of elastic elements connecting the movable part of the cutter with the housing and the cover with the formation of the oscillatory circuit and fastening elements, while the elastic elements are placed between the movable part of the cutter and the housing from the side opposite to the cutting direction according to the invention, the rolling elements are made in the form of two support rollers installed in contact with the movable part of the cutter and placed between the moving part of the cutter and the housing with a cover.

The support rollers are fixed in parallel with the possibility of rotation (rotation) in the front of the cutter body and are contacted by their cylindrical surface along a line with the plane of the moving part of the cutter adjacent to it.

The vibrating cutter is equipped with a safety elastic element located on the opposite side to the main elastic elements between the movable part of the cutter and the body, while a gap is provided between the safety elastic element and the moving part of the cutter.

All elastic elements are made of polyurethane.

The rollers are located under the moving part of the cutter.

The rollers are located above the moving part of the cutter.

The rollers are close to the front of the cutter.

Replacement in the oscillatory circuit of sliding friction with rolling friction allows for constant contact between the moving part of the cutter and the fixed part along the line, which significantly reduced friction losses. As a result of this, as well as due to the use of elastic elements made of polyurethane, it was possible to maximize the frequency of vibrational motion (more than 45 Hz) and speed. In this case, between the cutting insert and the cutting plane there is a series (sequence) of impulse impacts, causing the formation of microcracks and leading crack. The resulting chips instantly breaks off and flies off to the feed side. There is practically no contact between the front surface of the cutter and the chips, so the chips do not heat up and remain completely cold.

The use of support rollers adjacent to the plane of the movable part of the cutter and perceiving the reaction of resistance to the cutting forces in the vibratory cutter makes it possible to facilitate the reciprocating (oscillatory) movement of the moving part of the cutter by reducing friction.

Due to the placement of rolling elements - rollers between the movable and fixed parts of the cutter, it also allows to reduce friction and increase speed.

It is optimal to place the rollers on both sides of the moving part of the cutter, but you can place these elements on only one of the sides.

As rolling elements, rollers, such as needles, can be used.

Unlike the prototype, the inventive vibrating cutter is characterized by the presence of a protective elastic element located on the opposite side to the main elastic elements between the movable part of the cutter and the body. The use of such an additional element is due to an increase in the speed of movement of the movable part of the cutter, leading to a sharp instantaneous compression of the main elastic elements and the same sharp release. As a result, it becomes possible to strike the moving part of the cutter against the body, and the safety elastic element installed in this place absorbs the impact energy.

Patent studies have shown that the claimed technical solution meets the eligibility criteria.

The essence of the claimed invention is illustrated by drawings, where in FIG. 1 is a perspective view of a schematic illustration of a workpiece and a vibrating cutter with local cuts; in FIG. 2 is a longitudinal turning diagram; FIG. 3 is a diagram of transverse turning (trimming).

The inventive method of vibration cutting is as follows:

- the workpiece 1, mounted in the spindle 2 of the machine, rotates with an angular speed ω;

- the support, together with the tool holder and the vibration tool, moves towards the longitudinal feed;

- set the feed rate f and the cutting depth a progressively moved tool;

- the cutting part of the cutter, as will be described later, under the influence of cutting forces begins to oscillate with a frequency of more than 45 Hz, while the nature of the oscillatory movement is determined by the oscillatory circuit;

- impulse actions from the side of the cutter lead to the formation of microcracks in the cutting zone and the periodic formation of leading cracks and crushing of the chips, and as a result, the chip itself is practically not in contact with the front surface of the cutter and therefore remains cold.

The inventive vibration cutter includes a housing 3 with a cover 4. In the housing 3 is placed a movable part 5 of the cutter. A cutting insert 6 is fixed on the movable part 5 of the cutter. The cutter body 3 with the cover 4 fixed thereon is mounted in the tool holder 7 of the CNC lathe. The upper part of the tool holder 7 abuts against the protrusion of the cover 4.

In the front of the movable part 5 of the cutter, a groove is made. In this groove, two support rollers 8 are mounted, mounted on the cover 4 of the cutter. These support rollers 8 perceive the reaction of resistance to cutting forces. Each support roller 8 and the surface of the moving part 5 of the cutter in contact with it form a kinematic pair, and contact in this kinematic pair occurs along the line. Support rollers 8 provide horizontal movement of the movable part 5 of the cutter. The surfaces of the indicated kinematic pair are approximately the same in hardness (HRC 50-55). The rolling friction coefficient is 0.00015.

The design of the cutter includes a set of basic and protective elastic elements connecting the movable part of the cutter 5 with the housing 3 and the cover 4 with the formation of an oscillatory circuit.

The main elastic elements 9 are placed between the movable part of the cutter 5 and the housing 3 from the side opposite to the cutting direction with an interference fit of at least 1 mm. These elastic elements are periodically compressed under the influence of the movable part 5 of the cutter and return this movable part 5 to its original position, that is, provide oscillatory motion.

Safety elastic elements 10 are located between the housing 3 and the movable part 5 of the cutter on the opposite side to the main elastic elements 9, while a gap is provided between the safety elastic elements 10 and the movable part of the cutter 5. At large depths of cutting, it is possible to “press” the movable part 5 of the cutter to the side opposite to the main elastic elements 9 (impact). The presence of safety elastic elements 10 softens such a blow.

The elastic elements 9 and 10 are made of polyurethane.

The movable part of the cutter 5 rests on the roller guides 11. The roller guides 11 are located in the front of the cutter from below between the housing 3 and the movable part 5 of the cutter, and also from above between the movable part 5 and the cover 4, however, it is possible to use only one roller guide 11, for example, bottom under the movable part 5. Roller guides 11 can be made in the form of a set of thin rollers (needles) placed in a cassette 12 of polymer material.

The location of the roller guides 11 in the front of the cutter increases the manufacturability of the assembly.

An example of a specific implementation.

The cutter with a non-turning plate of Iscar company (Israel) IC-907 is fixed in the tool holder.

The processed material is steel grade 4340.

The diameter of the workpiece is 125 mm.

Feed f = 0.37 mm / rev.

Depth of cut a = 1.5 mm on one side (3 mm in diameter).

Cutting speed V _c = 350 m / min - 430 m / min - 450 m / min.

The part fixed in the spindle of the lathe rotates with an angular speed ώ = πn / 30 rpm, where n is the number of spindle revolutions - 1100 rpm.

For given cutting parameters, cutting forces P _x and P _y arise.

Under the influence of these forces with virtually no friction losses and high recovery ability of the elastic elements 9 of polyurethane, the movable part 5 of the cutter oscillates with high frequency. In this case, the amplitude of the oscillations can vary due to the use of polyurethane of different hardness: the greater the hardness, the lower the amplitude of the oscillations. However, it should be noted that for turning, the amplitude does not matter much.

In the cutting zone, in addition to the feed movement, there is a pulsed high-frequency impact on the body of the part, leading to the formation of microcracks and advancing cracks. The resulting chip 13 does not slip on the front surface of the cutting insert, but almost instantly fragmented, flies to the left side. As a result, the chips do not heat up.

The above examples are not exhaustive and it is possible to use various configurations and modifications of the invention without deviating from its essence, formulated in the proposed claims and defined by them.

Claims (8)

1. The method of vibration cutting with the formation of elemental shavings, including the rotation of the workpiece, the translational movement of the cutter made with a movable cutting part, elastic elements and a fixed part, providing oscillatory sinusoidal movement of the moving cutting part of the cutter under the action of cutting forces acting on the oscillating circuit, formed by the moving part of the cutter, the elastic elements and the fixed part using rolling elements, characterized in that as an element The rolling bearings use two support rollers installed in contact with the moving part of the cutter. 2. A vibration cutter comprising a housing with a cover and a movable part with a cutting plate, a set of elastic elements connecting the movable part of the cutter with the housing and the cover to form an oscillating circuit, and rolling elements, while the elastic elements are placed between the movable part of the cutter and the housing from the side opposite to the cutting direction, characterized in that the rolling elements are made in the form of two support rollers installed in contact with the moving part of the cutter and placed between the moving part of the cutter and the housing with yshkoy. 3. The vibrating cutter according to claim 2, characterized in that the support rollers are fixed in parallel with the possibility of rotation in the front part of the cutter body and contact their cylindrical surface along a line with the plane of the moving part of the cutter adjacent to it. 4. The vibrating cutter according to claim 2, characterized in that it is provided with a safety elastic element located on the side opposite to the main elastic elements between the movable part of the cutter and the housing, while a gap is provided between the safety elastic element and the movable part of the cutter. 5. The vibration cutter according to claim 2, characterized in that all the elastic elements are made of polyurethane. 6. The vibration cutter according to claim 2, characterized in that the rollers are located under the movable part of the cutter. 7. The vibration cutter according to claim 2, characterized in that the rollers are located above the movable part of the cutter. 8. The vibration cutter according to claim 2, characterized in that all the rollers are close to the front of the cutter.

Images