SU1355356A1 - Method of machining surfaces of rotation - Google Patents

Abstract

The invention relates to the treatment of surfaces of revolution by cutting and may find application in the processing of cylindrical parts made of viscous materials. The aim of the invention is to improve processing accuracy. During processing, the workpiece 1 and the cutting head 2 report rotation around their geometry axes 4 and 5 and relative feed movement. The axis 4 of the workpiece and the axis 5 of the cutting head are set at the crossing angle determined by the expression if arccos and, where d is the diameter of the machined surface; D is the diameter of the incisal head. The diameter of the cutting head is set smaller than the diameter of the workpiece by an amount the minimum value of which is equal to the thickness of the metal layer being cut off. 3 il. (L CZ from 01 ate O) (rig. 2

Description

The invention relates to metal cutting and can be used in mechanical engineering, mainly for processing cylindrical. parts made of viscous materials.

The purpose of the invention is to improve the accuracy of processing.

FIG. Figure 1 shows the relative position of the workpiece and the cutter head and the movements it communicates, the cross section perpendicular to the axis of the workpiece; in fig. 2 - the same plan view; in fig. 3 is a diagram of the formation of a profile of the treated surface.

For processing the workpiece. 1 use a multi-cutter head 2 with radially located cutters 3, which are equipped with polygonal or circular plates.

During processing, the workpiece 1 and the cutting head 2 are informed by continuous rotational movements around their geometry axes 4 and 5, respectively:

frequencies n, and n,

and

the movement of the feed S along the axis of the workpiece. The feed motion can be communicated either to the workpiece or to the cutting head.

The geometrical axis 4 of the workpiece and the axis 5 of the cutting head are installed in parallel. Planes with offset 1 at the crossing angle tf, the value of which is determined by the formula

The length of the meter is 30

the left axis is D cos Cf.

An ellipse most closely approximates a circle with diameter d if the radius of its curvature p at the vertex belonging to the major axis and in contact with the given circle is equal to the radius of this circle, i.e. p d / 2. The radius of curvature p of the ellipse at the specified vertex is equal to jo, where a and b are respectively large and 35 is small on the semi-axis of the ellipse. Then d d

(f arccos

where d is the diameter of the treated surface; D is the diameter of the incisal head.

The diameter D of the cutting head radial movement of the cutters set less than the diameter of the workpiece, d by an amount the minimum value of which is equal to the thickness of the metal layer being cut. If there is a solid defective layer on the surface of the workpiece, then the diameter of the cutting head is additionally reduced by the thickness of this layer and thus excludes the possibility of contact of the tips of the cutters with this layer, which increases tool life.

The angle tf between axes 4 and 5 is adjusted by turning the cutter head 2 around axis 6, intersecting below. The npHMbiMf angle with these axes and passing through the plane in which the tips of the incisors of the 3 heads are located. At the same time, when adjusting the angle q of crossing axes according to the proposed

five

0

The projection of the circle on which the tips of the incisors are located on a plane perpendicular to the axis 4 of the workpiece is a zlipse 7, whose radius of curvature at the point of contact with the machined surface is equal to the radius of this surface. Due to this, as well as the fact that the diameter of the cutting head is smaller than the diameter of the workpiece, the tips of the cutters 3 move along the trajectories, which over a considerable length do not deviate much from a given surface, which, in comparison with the known method, provides an increase in machining accuracy.

The proposed relationship for determining the installation angle t is obtained as follows.

It is known that the projection of a circle on the plane located to it at an angle g is an ellipse, the length of the major axis of which is equal to the diameter D of this circle, and the length

the left axis is D cos Cf.

An ellipse most closely approximates a circle with diameter d if the radius of its curvature p at the vertex belonging to the major axis and in contact with the given circle is equal to the radius of this circle, i.e. p d / 2. The radius of curvature p of the ellipse at the specified vertex is equal to jo, where a and b are respectively large and small for the semi-axis of the ellipse. Then d d

f

Assuming that D is the diameter of the cutting head, d is the diameter of the machined surface, the desired relationship is obtained for determining the angle (/ between the axes of the cutting head and the workpiece located in parallel flat

0

The cross section of the cylindrical surface is formed during processing as an envelope of a set of curves — trajectories of the tops of the cutters of the head relative to the workpiece. If there are cutters in the Z-head for one revolution of the workpiece, they form i Z curves, where i is the ratio of the angular velocities of the cutting head and the workpiece. For surface treatment with a tolerable cut value. / J, the ratio i of the rotational frequencies of the cutting head and the workpiece is set in accordance with the dependence

, 77, -1 d Z - D

where / 9 is the angle of rotation of the cutting head during the movement of the cutter in relative motion from the point A of contact with a circle of diameter d to the point B remote from this circle by the amount of allowable faceting & (Fig. 3). The value of this angle is determined by the expression

R + 1 (g × 4) 2

/ J arccos

where R D / 2; g d / 2; 1 R - g.

The distance L is removed from the given circle and the point C belonging to the circle with diameter D. Therefore, the height of the faceting when the axes of the workpiece and the head are parallel are

or

J V (R cos - 1) + (R-sin) t,

where X (., y - coordinates of point C.

When turning the tool head at an angle (/ the tip of the tool moves in relative motion to AB, and point C approaches the specified cylindrical surface of diameter d, oTo6

touch the plane of rotation of the workpiece to point C, the coordinates of which

X, Xj.

or

Example. Baseline data: billet diameter DO, 190 mm; diameter 35 of the treated surface d 182 mm; workpiece material - steel 12Х18НЮТ; equipment - a lathe equipped with an eight-blade cutting head (Z 8) with 40 cutting part made of VK8 alloy.

According to the standards for the cutting of stainless steels, it is accepted at 52m / min; feed per cutter for one revolution of the workpiece S 0.5 mm / rev. / (Rcos / i-l) + (Rsin cosc /) - g 45 d., G. To ensure the simultaneous operation of all the teeth of the head, its diameter D is taken smaller than the diameter of the workpiece by the thickness of the cutting layer, i.e. D 186 mm.

 The ratio i of the rotational frequencies of the head and the workpiece is adjusted on the basis that the angle of rotation / 5 is incisal. heads for the given source data- V +.

and Y ,, Y, -Why c.

The cutting height of the proposed method is less than the known and is

(/ "Y (xc - 1) + (Y (, cos v) - g or

Cutting speed V when machining enveloping head

V + f Dnj

R2 + l2 (r + j) 2

jj arccos2cr

The rotational frequencies of the workpiece and the head are adjusted according to dependencies.

g

7G (0 + D-i)

Hj n, L,

The minute feed S of the cutting head along the axis of the workpiece is determined by the formula

SM

SZ p

five

where S is the feed of the cutter along the axis of the workpiece, for one revolution; Z - the number of simultaneously working incisors. When processing the bat of the proposed method, all the teeth of the head, i.e. Z Z, which is significantly more than with the known method. This circumstance is one of the reasons for an increase in the productivity of processing by the enveloping heads according to the proposed method, since with an increase in the number of simultaneously working teeth, the feed rate along the workpiece and the productivity of processing increase proportionally.

 arc.c.os

(91 + 0, l) 2

2-93-2

 18

1) i D

51355356

.

and p that

The angle between the crossing axes of the head and the workpiece is adjusted according to

182 „/„ about That -.

(arccos V- arccos bg

The cut height of the machined surface is

J - ucos / i-D + CRsin / 4 cost /) -g

The method of processing the surfaces of rotation with a cutting head, according to which 15 the last and the joint joint cos 3) - "- (93 sin 18 cos 8.4:) -" is rotation and relative podagchu, axis of rotation of the cutting head and

  blanks set at an angle and with

When parallel x axis tool. the displacement, which is different in that, and the workpiece, the machined surface 20 that, in order to improve the accuracy, the processing has a much larger faceting

d l (Rcos / 3-l) - “- (Rsin /)) - g (93 cos l8 ° -2) -f (93sin 0.1 mm.

During processing, the workpiece is reported to rotate at a frequency of

52

P, -

V

/ H J () J (0.19 + 0.186-0.25 70 rpm;

6

and the incisal head - rotation with frequency

P

2 nj, - i 70.0.25 17.5 rpm, movement along the axis of the workpiece with the feed

0.5-8-70 280 mm / min

ten

Claims (1)

S S-Z Formula of Invention The method of processing the surfaces of rotation with a cutting head, according to which the last and the workpiece are rotated and relative to the pitch, and the axis of rotation of the cutting head and ki, the diameter of the trajectory of the tops of the incisors of the cutting head is set smaller than the diameter of the workpiece by an amount the minimum value of which is equal to the allowance, and the angle between the axes of rotation of the cutting head and the workpiece is set by the ratio (/ arccos where d is the diameter of a given surface rotation; D is the diameter of the incisal head. Fig 1 Fig.d Editor I. Casarda Compiled by, Semenov Tehred M. Khodanych Order 5742/11 Circulation 970 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Proofreader V. Booth ha