SU1421469A1 - Method of machining holes with rotary cutter - Google Patents

Abstract

The invention relates to the field of mechanical machining of holes with a rotating cutter and can be used on horizontal boring machines with numerical program control. The purpose of the present invention is to increase the accuracy when machining the holes with an allowance variable with the axis of the hole. Table 6 with part 1 installed on it is reported to the working feed, and sub-adjustment of the rotating cutter is carried out by changing the rigidity at the axial feed of the spindle 4 to the spindle head 7. The feed of the CTOvia with the workpiece is changed by an amount equal and equally directed with the axial feed of the spindle . 5 il. with S9

Description

(L

4 :: to

four

0

WITH

2. /

The invention relates to the field of machining and can be used on horizontal boring machines with numerical control.

The aim of the invention is to improve the accuracy when machining holes with variable allowances along the hole axis.

FIG. 1 shows the processing scheme of the hole according to the proposed method; in fig. 2 is a diagram of the action of axial and radial component reactions of the cutting force; in fig. 3 is a diagram of the deformation of the tool and the spindle from the axial component of the cutting force; in fig. 4 - the same, due to the radial component of the cutting force; in fig. 5 is a graphical scheme for determining the value of the tool set-up.

In part 1, a hole 2 is produced by a rotating cutter 3 mounted in the sliding spindle 4 on the boring machine 5. The parts 1 mounted on the table 6 of the machine report axial displacement Si, resulting in removal of the allowance t.

When boring the hole 2, the cutter 3 and the spindle 4 are affected by the reaction PI of the axial component of the cutting force applied at a distance r from the axis of rotation of the spindle, which gives rise to a moment bending the cutter from the surface of the part, and the spindle towards the surface parts (Fig. 3), as well as the reaction P 2 of the radial component of the cutting force, bending the cutter and spindle away from the surface of the part (Fig. 4).

The resultant deformation Y of the tool 3 and the spindle 4, which determines the difference in the total deformation of the tool and the spindle from the effect of force P and the total deformation of Y 2 from the force of force Pz, is equal to the subset value D of the tool tip due to wear. The magnitudes of the deformations Y and Y depend on the cutting mode and departure / spindle 4 with respect to the spindle head 7.

The differential equation of the curved axis of the cutter 3 and the spindle 4 from the action of the forces P and PI is determined by the expression

E.d.m (.),

modulus of elasticity of the tool / spindle; the moment of inertia of the tool / spindle; the magnitude of the cutter / spindle deformation due to the forces of P and Poison;

X is the distance of the place of application of force vectors P | and Pa relative to the diameter of the spindle for the cutter and the spindle head for the shpindle;

d / is the bending moment from the action of the forces PI and P2.

The total strain Y due to the force of PI is determined by the strain Y of the tool and the strain of the UT spindle.

where - / - y -

Have

2 P, .b

3 ../

yf

city /

five

0

five

g-e -1

where the PI reaction is the axial component of the cutting force acting on the tool and the spindle;

B is the distance of the force vector P to the diameter of the spindle (the pinching point of the cantilever);

g is the distance of the force vector Pi to the axis of the spindle (radius of the hole being machined);

/ is the distance of the force vector Pi to the end of the spindle head;

E and E are the moduli of elasticity of the cutter to the shpindde, respectively;

/ and / - moments of inertia of the tool and shpindde respectively.

y, -yf-y -p,. (.... b / 1 "1 ..:.

The total deformation Va due to the action of the reaction Pz of the radial component of the cutting force consists of the deformation U2 of the tool and the deformation of the UG spindle.

P2-b-C

0

at

i Y / L-P ../

five

0

3rd.

where P 2 is the response of the radial component of the cutting force acting on the cutter and the spindle; c is the distance of the force vector P to

neutral axis cutter. The resultant deformation V is equal in magnitude to the subset-up L of the tip of the tool as a result of wear, numerically determined by the difference Y and Y

 3-,

,,. (7

-P2 („+ 777).

45

 2 .... /

Based on the fact that during the processing of a hole of a given magnitude, the values of the parameters r,, E, D, I, i, and c are constant, we have

.with

L1

Xs

2nd -1

K, - b. ./

D.P., ((

3-.

- / (2) -P2- (Ks + K4-;)

(I)

The advancement of the spindle of the boring machine relative to the spindle head by the value of /, the value of which is determined from equation (1), is obtained the required value of the tool set-up.

The magnitudes of the forces P and P2 are determined by the expression

R | C, .G. .V -A, P, -S,

t - 5

V - A to AZ where Ci and C2 are coefficients depending on the type of turning;

the depth of the removed allowance; working feed when turning; cutting speed, coefficients depending on the material being processed;

"1," 2, U and 2, Wi and W2 are exponents depending on the material of the part, the type of turning, etc.

When machining a hole with a variable along the axis of the hole with an allowance t, the values Pi and P2 in expressions (1) - (3) change and, consequently, the machining accuracy decreases. Due to the fact that the other parameters C, S, V, A in formulas (2) and (3) in order to ensure the constancy of the surface roughness, tool wear are not subject to change, it is necessary to ensure during the processing And the tool needs to change accordingly the size of the overhang / spindle, expression (1), relative to the spindle head, depending on the changed and the size of the removed stock.

In the case of a monotonous change in the allowance, the change in the spindle override is

The spindle head is also a function of continuous and monotonous, i.e. in the process of supplying Si parts, depending on whether the machine spindle increases or decreases, the machine spindle is reported to continuously or axially move S parts depending on the change. removed allowance. The resulting cutting feed in connection with the continuous axial movement of the S-2 or Su spindle may be greater than the supply of Si parts or less, which leads to a change in the ratio of silP and P2, equation (2) and (3), and a decrease in machining accuracy . Consequently, the table with the detail must be reported with an additional feed movement S4 or Ss, which is equal in magnitude and direction to the continuous movement Sj and S3 of the spindle, respectively, i.e., the compensating movement of the spindle.

20

Claims (1)

Invention Formula The method of processing holes with a rotating cutter, according to which the details report the working feed, and the cutter mounted on the spindle, the sub-adjustment movement, characterized in that, in order to improve the accuracy when machining holes with variable along the hole axis, the allowance, the sub-adjustment movement the cutter is provided with a message to the axial feed spindle, and the feed of the part is changed by an amount equal and equally directed with the axial feed of the spindle. . PI (rig 2 h ff /; A ц11 i U1 7j yj V 112.3 fPuz.