RU2247642C1 - Method for polishing by means of abrasive-diamond petal-type wheels with parametric oscillation - Google Patents

Abstract

FIELD: machine engineering, possibly dimensionless finishing of part surfaces by means of petal type wheels.

SUBSTANCE: wheel is assembled of petals of grinding cloth and it is mounted by acute angle relative to plane normal to rotation axis. Petals of wheels are made of double-side grinding cloth in the form of ellipses. Small axis of ellipse is equal to diameter of wheel; large axis is determined according to inclination angle of wheel.

EFFECT: enlarged manufacturing possibilities of wheel due to grinding by means of two ends of petals, enhanced efficiency and quality of grinding due to increased axial rigidity of wheel.

3 cl, 6 dwg

Description

The invention relates to mechanical engineering, namely to the machining of metals, and can be used for grinding and polishing surfaces of parts with their dimensionless final machining with flap wheels.

A known method of abrasive processing, which is carried out by a prefabricated abrasive tool made in the form of a pair of abrasive wheels fixed at an angle to each other on a common shaft with axial clearance [1].

The disadvantages of this method are the limited technological capabilities for decorative finishing and finishing of shaped surfaces, as well as difficulties in achieving a wide range of quality of the machined surfaces, while having minimal axial rigidity and working only on one side of the peripheral abrasive surface, it is impossible to achieve high performance.

A known method of finishing abrasive machining with a pre-fabricated abrasive tool made in the form of a pair of abrasive wheels fixed at an angle to each other on a common shaft with axial clearance, and the tool is equipped with a tension spring placed by a method adjacent to the ends of the abrasive wheels, which are installed with the possibility of angular rotation [2 ].

The disadvantages of this method are:

- minimum axial rigidity of the tool, not allowing to achieve high productivity of the method;

- work only on one side of the peripheral abrasive surface of the tool, greatly increasing the complexity of processing;

- limited technological capabilities for decorative finishing and finishing of shaped surfaces;

- difficulties in achieving a wide range of quality of the treated surfaces.

All this reduces processing productivity, quality and leads to increased tool consumption.

The objective of the invention is to expand the technological capabilities of the method by providing the possibility of processing with two ends of the petals of the tool, which is installed at an angle to the axis of rotation, increasing productivity and quality by increasing the axial rigidity of the tool through the use of abrasive petals in the form of an ellipse.

The problem is solved using the proposed method of polishing with abrasive-diamond flap wheels with parametric oscillation, in which the workpiece and the flap wheel are informed by rotational movements and reciprocating feed movements along the surface to be machined, while the wheel is made of petals of the grinding skin and set at an acute angle to a plane perpendicular to the axis of rotation, and the petals are made of a double-sided grinding skin in the shape of an ellipse, the small axis of which horn is equal to the diameter of the circle, and the major axis depends on the angle of inclination of the circle and is determined by the formula

where b is the major axis of the ellipse;

D is the outer diameter of a circle mounted at an angle to a plane perpendicular to the axis of rotation;

α is the angle of inclination of the circle to a plane perpendicular to the axis of rotation, which is determined by the formula

In - the height of the circle.

In addition, pre-polishing is carried out with a circle that is set to a zero angle of inclination of the abrasive-diamond petals and which is equipped with oblique washers installed in pairs from each end, while the angle between the ends of the oblique washer is half less than the angle of installation of the circle.

Figure 1 shows the circle for the implementation of the proposed method, configured for final polishing, general view; figure 2 is a circle configured for pre-polishing, a partial axial section; figure 3 is a view along a in figure 2; figure 4 - element B in figure 1; figure 5 - element B after half a turn of the circle relative to figure 4; figure 6 is an ellipsoidal petal of a double-sided grinding skin.

The proposed method of polishing is carried out by abrasive-diamond flap wheels 1 with parametric oscillation, in which rotational movements and reciprocating feed movements along the work surface are reported to the workpiece and flap polishing wheel. The petal abrasive wheel 1 consists of the petals 1 ^{1 of the} grinding skin and is installed at an acute angle α to a plane perpendicular to the axis of rotation. Circle 1 is mounted on spindle 2 and secured with washers 3 with nut 4.

The petals 1 ¹ are cut from a double-sided sandpaper in the shape of an ellipse, the small axis of which is equal to the diameter D of circle 1 in an inclined position, and the large axis depends on the angle α of inclination of circle 1 and is determined by the formula

where b is the major axis of the ellipse;

D is the outer diameter of a circle mounted at an angle to a plane perpendicular to the axis of rotation;

α is the angle of inclination of the circle to a plane perpendicular to the axis of rotation.

For installation and smooth adjustment of the angle of inclination, the circle 1 is equipped with oblique washers 3, which are installed in pairs from each end of the circle.

The angle between the ends of the oblique washer 3 is half less than the angle α of the installation of the circle 1.

During assembly and commissioning, release nut 4 and, by turning one washer 3 relative to another in each pair of washers, set the angle α of inclination of circle 1 in the range from 0 ° to α _max , where α _max is the maximum possible angle of inclination of the circle to a plane perpendicular to the axis of rotation which is determined experimentally. Recommended angle α to choose according to the formula

where B is the height of the circle.

At large angles of inclination of the circle, productivity increases, but the quality of the surface being machined deteriorates.

When pre-polishing the circle is set at a zero angle (see figure 2). In this case, the peripheral working surface of the circle acquires a wavy shape and, accordingly, a profile in the form of a circular wavy line.

The height Δ (Fig. 3) of the wave-shaped protrusion relative to the depression corresponds to the greatest interference during the work of the circle, and the length of the protrusion (equal to half the length of the outer working surface of the circle) corresponds to the largest length of the contact zone of the circle with the workpiece surface being machined.

Due to the wavy shape of the working surface of the circle, the main force on the surface to be treated is carried out by the parts of the petals located on the wave-like protrusions and having the greatest deflection (see Figs. 4-5).

In connection with the foregoing, in the process of preliminary polishing it is possible to remove large allowances (for example, up to 0.3 mm) when using coarse-grained abrasive skins (grain size 16-80) and high cutting speeds (15-35 m / s).

This process is actually a type of grinding and is effective for preparing surfaces for fine polishing and before metal coating.

Finishing polishing according to the proposed method with a flap wheel with parametric oscillation (Fig. 1) is intended to reduce the surface roughness parameter (to Ra = 0.1 ... 0.8 μm) without eliminating deviations in the shape of the parts.

The greatest effect of the use of oscillating polishing is achieved with decorative finishing and finishing of shaped surfaces, for example polishing of cylindrical and conical surfaces, processing of molds, dies, etc., polishing curved surfaces of automobile bodies, refrigerators, etc. for painting.

Polishing according to the proposed method with this wheel is carried out mainly according to one cutting pattern, which is based on the use of high cutting speeds (10 ... 40 m / s), approaching the grinding speed. The peripheral speed of a circle during oscillating polishing of parts from: steel, nickel and chromium is 20 ... 35 m / s; copper, brass and bronze - 16 ... 25 m / s; aluminum, zinc and lead - 12 ... 20 m / s.

The circles that are most suitable for the proposed method are electrocorundum and silicon carbide skins on a fabric and paper basis with a grain size of 8-M40, as well as diamond and elbor skins with a grain size of 12-MZ on an elastic bond, while the latter are highly resistant.

To implement this method, circles of water-resistant diamond-abrasive skins are used when processing parts made of steel, cast iron and brass, and an emulsion is used as a cooling liquid; from non-waterproof skins - mineral oils.

The proposed method of polishing with petal wheels with parametric oscillation expands technological capabilities by providing the possibility of processing the two ends of the petals that make up the circles, improves productivity and quality of processing by setting the wheel at an angle to the axis of rotation, increasing axial stiffness and using abrasive petals in the form ellipse.

Sources of information

1. A.S. 689823 USSR, MKI B 24 D 5/00. Prefabricated abrasive tool, 1977.

2. A.S. 1692824 USSR, MKI B 24 D 13/00. Prefabricated abrasive tool. A.V. Chemersky and V.N. Cheshev. No. 4700372/08, declared 04/18/89, publ. 11/23/91. Bull. No. 43 is a prototype.

Claims (3)

1. The method of polishing with abrasive diamond flap wheels with parametric oscillation, in which the workpiece and the flap wheel are informed of rotational movements and reciprocating feed movements along the surface to be machined, characterized in that the circle is made of the flaps of the grinding skin and is set at an acute angle to the plane perpendicular to the axis of rotation, and the petals are made of a double-sided grinding skin in the form of an ellipse, the small axis of which is equal to the diameter of the circle, and the major axis Avis on the angle of the circle and defined by the formula: b = D / cos α, where b is the major axis of the ellipse; D is the outer diameter of a circle mounted at an angle to a plane perpendicular to the axis of rotation; α is the angle of inclination of the circle to a plane perpendicular to the axis of rotation, determined by the formula α≤arc tg (V / D); In - the height of the circle. 2. The method according to claim 1, characterized in that the preliminary polishing is carried out with a circle tuned to a zero angle of inclination of the abrasive-diamond petals. 3. The method according to claim 1 or 2, characterized in that it is carried out in a circle, which is equipped with oblique washers installed in pairs from each end, while the angle between the ends of the oblique washer is half the angle of the circle.

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