RU2296652C1 - Needle-milling cutter for processing of planes with pulse loading - Google Patents

Abstract

FIELD: the invention refers to the field of mechanical processing, cleaning the surfaces of metals and processing of planes on machines.

SUBSTANCE: the arrangement for processing planes includes a needle-milling cutter having a body with bundles of wire pile fixed on it. For expansion of technological possibilities the radial T-shaped grooves are fulfilled on the face of the body. The plates are installed in the grooves with possibility of radial travel. At that the needle-milling cutter is provided with buckets of segmental form rigidly installed on the plates in which wire bundles of pile are fixed with the aid of bearings located at the both sides of the T-shaped grooves on which the buckets lean with the aid of stretching springs located in the slots of the body and fixed on the exterior face of the plate and the body for displacement of the plate to the center of the needle-milling cutter with the aid of a generator of hydraulic pulses and a waveguide whose exterior surface contacts with the inner faces of the plate and is located under a sharp angle α to its longitudinal axle. The waveguide takes the shocks of a striker of the generator of hydraulic pulses and is designed for placing the hollow spindle in the central longitudinal opening for fixing the needle-cutter.

EFFECT: expands technological possibilities of the needle-milling cutter.

7 dwg

Description

The invention relates to devices for mechanical processing by needle milling to remove slag from the surface of metals, corrosion products, mill scale, burrs, for cutting metals, and is intended for mechanization of deburring, rounding edges and processing planes on milling, multi-position and multi-operation machines.

A device for cleaning surfaces from corrosion products, scale, etc., containing a drive disk with tufts of pile alternately arranged around its circumference and abrasive cylinders installed in the through holes of the disk [1].

The disadvantages of the known device is the inability to intensify the process of processing and removal of metal due to the fact that the abrasive cylinders rotate only due to frictional forces, in addition, as the abrasive wears, the cylinders will be pressed against the work surface with less force due to the properties of the pressure springs, moreover, and the device does not allow the full use of the cutting properties of the abrasive, which requires a very high speed of rotation (of the order of several thousand revolutions with such small cylinder diameters) However, it is difficult to implement for dynamic reasons, thereby reducing productivity and processing quality.

In addition, with an increase in the clamping force of the device to the surface to be treated, the tufts of the pile will bend as much as possible without cutting the metal.

The objective of the invention is the expansion of technological capabilities, improving the quality and productivity of processing by communicating to the segmented bundles of wire pile low-frequency, independent of the frequency of rotation of the needle cutting, radial-return oscillations, increasing the intensification of the process of needle cutting due to the application of radial pulsed force to the segments, allowing cutting not only the front, but also the lateral surfaces of the wire pile, as well as by increasing the contact area of the needle cutter with the workpiece.

The problem is solved using the proposed device for processing planes, including a needle cutter, designed to be installed on the machine spindle and containing a body with tufts of wire pile fixed to it, and radial T-shaped grooves are made on the end of the body, in which the rods are mounted for radial movement having a cross-sectional shape corresponding to the shape of the groove, while the acupuncture is equipped with segment-shaped glasses rigidly mounted on planks, in which wires are fixed bunches of pile, bearings located on both sides of the T-grooves on which the glasses rest, tension springs located in the grooves of the body and fixed to the outer end of the strap and the body, to move the strap to the center of the needle mill, the hydraulic pulse generator and the waveguide, the outer the surface of which is in contact with the inner end of the bar and is located at an acute angle α to its longitudinal axis, and the waveguide perceives the impacts of the hammer of the hydraulic pulse generator and is intended to be placed I in the central longitudinal bore of the hollow spindle for fastening iglofrezy and an inner end strap formed at an acute angle α to the transverse plane of the straps.

Design features of the proposed device are illustrated by drawings.

Figure 1 shows the proposed device with a face needle cutter, a longitudinal section; figure 2 is a General view from below according to figure 1; figure 3 is a diagram of a flat needle cutting and General view of the needle cutter according to B in figure 1; figure 4 is a section along b - In figure 1 and the position of the wire pile under load; figure 5 is a section along D - G in figure 4; in Fig.6 - the position of the wire pile under the action of a pulsed load, allowing you to move the segmented beams radially from the center of the needle; Fig.7 - the position of the wire pile when removing the pulse load and the action of tensile springs, allowing you to move the segmented beams radially to the center of the needle cutter.

The proposed device is designed for intensive high-performance machining of metals and alloys by intermittent face needle-cutting, which is informed by the rotational movement V _and , and the workpiece, together with the table, makes reciprocating movements S _pr and transverse feed S _pop for each double stroke of the table.

The needle cutter consists of a housing 1, at the end of which glasses 2 with tufts of wire pile 3 in the form of segments, having the shape of a circle-sector, are fixed with a possibility of radial movement.

For this purpose, radial T-shaped grooves 4 are made at the end of the housing 1, in which, with the possibility of radial movement, there are strips 5 having a cross-sectional shape corresponding to the shape of the groove 4.

Segment cups 2 are rigidly fixed to the strips 5 and, due to their length, rely on bearings 6 located on both sides of the T-grooves 4.

Each bar 5 is equipped with a tension spring 7, which is fixed with a pin 8 on the outer end of the bar 5 and the housing 1. The purpose of the springs 7 is the constant displacement of the bars 4 to the center of the tool. For safety and convenience of working with the tool, the springs 7 are located in the radial grooves 9 of the housing 1.

In the central longitudinal hole of the hollow spindle 10 on which the tool is mounted, there is a waveguide 11 having an outer surface 12 in contact with the inner end of the strip 5, located at an acute angle α to the longitudinal axis.

The waveguide 11 with one end face (the upper one, according to FIG. 1) perceives the impacts of the hammer 13 of the hydraulic pulse generator (GGI) (not shown) [3, 2]. On the opposite end (lower, according to figure 1) of the waveguide 11 acts on the compression spring 14.

The inner end of the strip 5, with which it is in contact with the waveguide 11, is made at an acute angle α to the transverse plane of the strip.

The considered design of the needle cutter allows you to load segmented glasses with bundles of wire pile in the radial direction of the pulse P _them load.

A device with an acupuncture works as follows.

The tool is mainly used for flat needle milling (see figure 3) when working with the end face of this disk tool.

The insertion load, acting normal to the workpiece surface being machined, is created by the machine mechanisms, as with traditional flat needle-milling. The choice of the size of the insertion load depends on the specific processing conditions and technical requirements for the surface to be treated.

A hydraulic pulse generator is used as a mechanism for pulse loading P _of segmented cups with wire tufts of pile [3, 2]. With flat needle-milling, the workpiece, together with the table, makes reciprocating movements S _pr and transverse feed S _pop for each double stroke of the table, and the tool is given a rotational movement V _and . The GGI creates a periodic impulse P load for _them and by means of the striker 13 transfers it to the waveguide 11 in the direction of the spindle axis (according to FIG. 1, from top to bottom). The impulse shock load P _them , overcoming the resistance of the compression spring 14 by means of the conical part of the waveguide 12, acts on the straps 5 with segmented cups 2 with tufts of pile 3, moving them across the spindle axis in the radial direction S _p from the center to the periphery by the amplitude A _a , (see Fig.6). After the impact is completed, the segmented cups 2 return to the center (see FIG. 7) using springs 7, and the waveguide 11 is retracted upward using the spring 14 to its original position (according to FIG. 1).

As a result of the impact of the striker 13 at the end of the waveguide 11, shock and oppositely directed pulses of the same amplitude and duration arise in the striker and waveguide, each of which will act on segmented glasses with tufts of pile and the treated surface with a cycle equal to double pulse duration.

Having reached segmented glasses and tufts of pile, the shock impulse is distributed on the passing and reflecting ones. The passing impulse forms the dynamic component of the cutting force. The ability to rationally use the energy of shock waves is determined by the size of the instrument.

As a result of superimposing on the rotational movement of the tool pulsed radial movement of the segmental glasses with tufts of pile, a cross movement of tufts of tufts of the tool is created relative to the vector of the longitudinal feed rate of the workpiece S _pr and the cutting speed and friction force are periodically changed. Moreover, there is a change in the sliding direction of the segmented glasses with tufts of pile relative to the workpiece being processed, the pile begins to work both with the front surface (see Fig. 4) and the side (see Fig. 6-7) surfaces; changes in the direction of increasing the width of processing in one pass In _1pr and the intensity of material removal. At the same time, metal removal and chip formation are facilitated, pile self-sharpening is improved, and variable forces are actively redistributed in the cutting plane, as a result of which self-oscillations are completely suppressed. In addition, this allows to increase the number of actively working pile wires and to intensify the cutting of the protrusions of surface irregularities.

By combining the pulsed reciprocating radial movement of the segmental cups with tufts of tufts and the rotational movement of the tool, a wear-resistant regular microrelief is formed on the treated surface with the cross direction of the patterns and roughnesses of small and uniform height, the quality of the surface layer of the part is improved, and self-oscillations are quenched. Moreover, the working conditions of the pile are improved, the material removal rate is increased, and favorable kinematics of the movement of pile bundles relative to the workpiece is created, which also reduces the roughness of the treated surface.

The proposed device can improve the performance of needle-milling due to the combination of roughing and finishing.

Thus, acupuncture is intensively acting on the surface to be treated with pulsed loading of the tool bundles, which significantly improves the quality of the processed surface and increases productivity several times.

Production tests were carried out using a special stand. The values of technological factors (impact frequency, feed rate) were chosen in such a way as to ensure the multiplicity of impact on the elementary area of the treated surface in the range of 6 ... 10. A further increase in the frequency of exposure leads to the appearance of large inertial forces and vibrations.

Before starting a new tool, the working surface of the wire pile was ruled by grinding it in assembled form. As a pile, a steel spring wire with a diameter of 0.5 ... 1.0 mm from steel 65 G.

In the process of processing the surface of a longitudinally moving workpiece, the needle cutter was pressed against it with an interference fit N. Due to the discontinuous working surface of the tufts of pile, the main force acting on the surface being machined is carried out by the first wire elements of the same bundle in the direction of rotation (see Fig. 4) having the largest free length l deflection f. The wire elements adjacent to them elastically compress them, slightly increasing the concentrated total effect on the surface to be treated.

In known constructions, needle-cutter contact with the cut allowance and cutting is carried out by wire elements on the front surfaces.

In the proposed device, the needle cutter is in contact with the cut allowance and the wire elements are cut not only by the front surfaces (see Fig. 4), but also by the side surfaces located both on the right (see Fig. 6) and on the left (see Fig. 7 ) relative to the front surface. Contact by the side surfaces is carried out alternately depending on the direction of the radial feed S _{p of the} tufts of pile and the direction of deflection f.

This intensifies the processing and improves the quality of processing.

The device is advisable to use when cleaning (without removing chips) and finishing (with removal of chips) processing of workpieces on milling and cleaning machines. For finishing processing, it is necessary that the hardness and tensile strength of the material of the wire elements of the pile be 1.5 ... 2 times higher than these parameters of the material of the workpiece, the ratio l / i, where i is the smallest inertia radius of the cross section of the wire elements, was in the range of 50 ... 100, and the coefficient K _{p of the} density of the wire pile was in the range of 0.7 ... 0.9, while the tightness should be H = 0.7 ... 1.5 mm. The operating modes of the device can be recommended as follows. The peripheral speed for finishing processing is 2 ... 5 m / s. The longitudinal feed is determined by the formula S _CR = L · n (mm / min), where n is the frequency of rotation of the device, min ^-1 ; the value of L (mm) depends on the interference and the diameter of the disk and is determined empirically or by calculation.

Tests of the needle-milling device during the finishing of the workpiece from a hot-rolled strip of steel 20 showed that the needle-mill cuts off scale from the surface to be treated together with the hardened layer, while during the needle-milling process, due to the impulse loading and the radial reciprocating movement of the tufts of pile, the treated surface is hardened, the force is pressed Acupuncture to the workpiece’s work surface is 200 ... 600 N per 10 mm of the width of the acupuncture working surface, and the tangential The cutting force is 150 ... 550 N.

For finishing and cleaning treatment with the proposed device with a needle mill, it is necessary to comply with the conditions K _p = p / σ _in = 1.5 ... 2.0; where p is the pressure during acupuncture, MPa; σ _in - the tensile strength of the material of the workpiece, MPa.

The choice of the appropriate pressure p depends on the physicomechanical properties of the material of the wire pile, on the stiffness and density of the latter, as well as on interference N.

When finishing metal processing with the proposed device with acupuncture, the hardness of the treated surface is increased, as a result, the wear resistance of the treated surface and the quality of the processing are improved, the roughness of the treated surface is reduced, and the processing productivity and tool life are increased. The magnitude of the force of the pulse loading of the tool was P _imp = 255 ... 400 kN.

Production tests have shown that the proposed device with a needle cutter intensifies the processing process due to the increase in the contact area of the workpiece with the tool in one pass, allows you to get the intersection at an angle of the trajectories of the tufts of pile with the direction of the original roughness. The conditions for self-sharpening the wire elements of the pile are improved.

The device expands the technological capabilities of flat needle-milling, improves the quality and productivity of processing due to the communication of low-frequency, independent of the tool rotation speed, radial oscillations to the pile beams, intensifies the needle-milling process by applying a radial pulsed force to the pile beams, which allows cutting not only front, but and lateral surfaces of the wire elements of the pile, as well as by increasing the area of contact of the tool with the workpiece.

The advantage of the needle-cutting device is the ability to smoothly control the amplitude of oscillating movements, which makes it easy to optimize the processing process in a production environment when the material being processed, chemical-thermal operation, cutting wire elements of the tool, technical conditions, cutting conditions.

Information sources

1. A.S. USSR 1493248, MKI A 46 V 7/08 // 24 V 45/00. Device for surface treatment. Perepichka E.V. and Skalko N.S. Application No. 3984461 / 31-12, application. 12/04/85, publ. 07/15/89. Bull. No. 26 is a prototype.

2. Kirichek A.V., Lazutkin A.G., Soloviev D.L. Static-pulse processing and equipment for its implementation // STIN, 1999, No. 6. - S.20-24.

3. RF patent 2090342. Lazutkin A.G., Kirichek A.V., Soloviev D.L. Water hammer device for processing parts by surface plastic deformation. 1997. Bull. Number 34.

Claims (1)

A device for processing planes, including a needle cutter, designed for installation on a machine spindle and comprising a housing with tufts of wire pile fixed on it, characterized in that radial T-shaped grooves are made at the end of the housing, in which the rods are mounted with the possibility of radial movement a cross-sectional shape corresponding to the shape of the groove, while the acupuncture is equipped with segment-shaped glasses rigidly mounted on the slats, in which wire bundles of pile are fixed, with bearings located on both sides of the T-grooves on which the glasses rest, tension springs located in the grooves of the housing and fixed to the outer end of the strap and the housing to move the strap to the center of the needle mill, a hydraulic pulse generator and a waveguide whose outer surface is in contact with the inner end straps and is located at an acute angle α to its longitudinal axis, and the waveguide perceives the impacts of the hammer of the hydraulic pulse generator and is designed to be placed in the central longitudinal hole a spindle for fastening iglofrezy logo, and the inner end of strap formed at an acute angle α to the transverse plane of the straps.

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