SU1255303A1 - Method of machining complex surfaces - Google Patents

Abstract

The invention relates to the treatment of complex surfaces such as blades, turbine blades with a rotating face milling cutter with longitudinal and transverse lines. In order to improve the quality of processing by stabilizing the height of the interstitial ridges during the longitudinal passage, the axis of the cutter is continuously rotated by the angle of- relative to the surface to be treated, which is determined depending on the cutter radius R, the given height of 4th interstitial ridges, S value of the transverse feed and the radius g of the curvature of the cross section of a complex surface on the width of the line to be processed according to the dependence ot arccos C-Vl / sg. s (o (l ins spl

Description

one

The invention relates to mechanical engineering and can be used in the machining of various parts bounded by complex surfaces, such as propeller and air blades, turbine blades, and the like.

The purpose of the invention is to improve the quality of processing by stabilizing the height of interstitial ridges.

FIG. 1 shows the processing scheme according to the proposed method; in fig. 2 is a profiling scheme.

-Complex surface 1 is machined with an end mill 2, which is rotated at a cutting speed around its axis 3. The processing is carried out with stitches, for which the mill reports a continuous longitudinal feed S and a period of 135353032 relative to the surface

The resulting formula is inconvenient for practical use. With plenty. Precise accuracy (accuracy less than 10%) is simplified when replacing cos Ы / 2 and sinci / 2 with the function of their approximate 10

15

cJ.

correspondingly

about

And - And using an approximate formula

П t а 1 ± а / 2.

where a is i 1.

L - §1 D - 1

ft - 8 (p b

Then

Similarly, it can be shown that when machining a convex surface

20

The following line is 3 "at a distance to go to the cross section S between the lines.

The milling cutter is mounted to the surface to be machined so that its axis of rotation is inclined to the direction of the longitudinal feed at an angle of Ы. The value of this angle during processing is continuously changed according to

.8d. one

U arccos R

(- - -) 52 - j (1)

with

R

where R is the radius of the end mill, mm; & - given height, interstitial ridges, mm; the value of the periodic transverse feed between the lines, mm;

the radius of curvature of the cross section of a complex surface on the width of the stitch to be processed, mm,

the minus sign corresponds to concave bones and plus to convex bones.

The dependency is obtained as follows.

It follows from FIG. 2 that when line-cutting a concave surface with a tight tool, interstitial ridges are formed, the height of which

l OM - ON - NK

/ - --t f2 (r-p) si.n2 | .

cJ.

correspondingly

about

And - And using an approximate formula

П t а 1 ± а / 2.

where a is i 1.

L - §1 D - 1

ft - 8 (p b

Then

Similarly, it can be shown that when machining a convex surface

(2)

When machining an inclined face cutter, the stitch surface is an ellipse, the radius of curvature of which at the point of contact with the nominal

In the particular case, when processing a flat surface, for which r ", the dependence is known

 . & SV8P. the surface is equal to R / cosct, where R is the radius of the cutter, oL is the angle between the plane of rotation of the cutter with the normal and the nominal surface (the angle between the axis of rotation of the cutter and the direction of the longitudinal feed S) /. Considering that the width of the line is significantly less than half the length of the ellipse, with sufficient accuracy, the average value of the radius of curvature of the line in cross section, perpendicular to the direction of the longitudinal feed, is

 R ..

 Cosci

(3)

From equations (2) and (3) follows the desired dependence (1).

55

about rmu l and

the invention

The method of treating complex surfaces with an end rotary milling cutter, which is reported to have a longitudinal and periodic cross feed, while the axis of rotation of the milling cutter is set at an angle to the treated surface, which is characterized by the fact that, in order to improve the quality of processing by stabilizing the height of the interstitial ridges, the angle of inclination of the milling axis to the surface being treated, o in each cross section is determined by the dependence

o (. arccos

R) R (-52 - g-

where R is the radius of the end mill;

A - specified height of interstitial

filing;

S - the value of the periodic transverse flow;

g is the radius of curvature of the cross section of a complex surface on the width of the line to be processed,

the minus sign corresponds to the treatment of concave, and plus - convex surfaces.

FIG. f

Editor S. Pekar

Compiled by M. Kolbich Tehred L. Serdyukova

Order 4751/12

Circulation 1001

VNIIPI USSR State Committee

on inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5

Production and printing company, Uzhgorod, st. Project, 4

FIG. 2

Proofreader T. Kolb

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Claims (1)

Claim A method of processing complex surfaces with a rotary milling cutter, which 1235303 swarm inform the longitudinal and periodic transverse feed, while the axis of rotation of the cutter is set at an angle to the surface to be machined, which is characterized in that, with 5 goals to improve the quality of processing by stabilizing the height of the interstitch ridges, the angle of inclination of the axis of the cutter to the surface to be machined is <7 in each the cross-section is determined by the dependence of arccos R corresponds to the treatment plus - convex over- where 4 , R is the radius of the face mill; Δ is the specified height of the interline feed; S is the value of the periodic transverse feed; g is the radius of curvature of the cross section of a complex surface at the width of the line being machined, the minus sign is concave, nost. (8L ₊ K <C2 - _r '>