SU1650372A1 - Method for machining parts having round and polyhedral surfaces - Google Patents

Description

one

(21) 4652147/08 (22) 02.17.89 (46) 05.23.91. Bul No. 19

(71) Novopolotsk Polytechnic Institute. Leninsky Komsomol of Belarus

(72) V. Danilov (53) 621.941.2 (088.8)

(56) USSR Author's Certificate No. 1355355, cl. B 23 B 1/00, 1985.

(54) METHOD FOR TREATING DETAILS WITH ROUND AND MULTIPLE SURFACES

(57) The invention relates to methods for cutting materials and will find application in mechanical engineering when machining parts with round and multi-faceted surfaces. The aim of the invention is to improve the accuracy of machining round and multi-faceted surfaces by reducing the influence of the deformation of the part upon it under the action of the cutting head. The cutter 4 is displaced relative to the plane passing through the axis of rotation of the part 1. and the cutting head 5 in the direction opposite to the direction of rotation of the part 1. In this case, the offset angle of the cutter 4 is selected from the relation a arctgPy / Pz. where a is the angle of the cutter to this plane; Py and Pr are the radial and tangential components of the cutting forces acting from the cutting head on the workpiece. Zil.

Have

Yo

about eaten about

SA) P |

Yu

eight

The invention relates to methods for processing materials by cutting and will find application in mechanical engineering when machining parts with round and multi-faceted surfaces on one machine.

The purpose of the invention is to improve the precision of machining round surfaces while maintaining the precision of machining multifaceted surfaces by reducing the effect of deformation of the part on it under the action of a cutting head.

Fig. 1 shows a kinematic processing scheme of a part with round and polyhedral surfaces; in fig. 2 shows the relative position of the tools and the workpiece in the plane of its rotation; in fig. 3 shows the influence of the direction of deformation of a part on the accuracy of machining a round surface.

On the workpiece 1, a round 2 and a multifaceted 3 surface is machined, respectively, by a cutter 4 and a cutting head 5 equipped with cutting teeth 6. The workpiece 1 and the cutting head 5 are rotatably mounted around their axes 7 and 8. The cutter 4 is set to the vertex is separated from the plane passing through the axes 7 and 8. at a distance h. The tip of the tool is displaced from this plane to the distance h in the direction opposite to the direction of rotation of the workpiece I. The value of h is adjusted by the formula

h tg sin arctg -5

iГг.

(one)

where Py and Pz are respectively the radial and tangential components of the cutting force acting on the workpiece 1 from the cutting teeth 6 of the cutting head.

The cutter 4 and the head 5 are capable of independent movement in the radial and longitudinal directions.

During processing, the workpiece 1 is reported to rotate Bi with a frequency m around the axis 7. The circular surface 2 is machined with a cutter 4, which is reported to have a feed movement Pz. The multifaceted surface 3 is machined with a cutting head 5, which is reported by the rotation of Ba with the frequency P2 around the axis 8 in the direction coinciding with the rotation of the workpiece, and the feed movement of Sch.

The frequency ratio of the cutting head and the workpiece is set according to the known dependence in accordance with the profile of the faces of the surface 3, and the number of cutting teeth 6 of the head 5 is set depending on the number of these faces and the ratio na / ni. Pzi P4 speeds of movement are chosen according to standards, and they may be the same or different, but turning of a circular surface should be ahead of the processing of a multifaceted surface.

During the machining cycle of a part, cutting with both tools is carried out both jointly and separately, depending on the length of the round and polyhedral surface and the values of the tool feeds. For

productivity increase processing with both tools as much as possible combine in time.

From each of the tools on the workpiece, cutting forces act

cause it to bend. The cutting force on the side of the cutter 4 acts continuously, and on the side of the cutting head 5 is intermittent and varies in magnitude, since the cutting teeth 6 come into operation periodically and carry out processing at a variable depth of cut. The maximum value of the cutting force P corresponds to the greatest depth of cut, i.e., when the tooth 6 is in the middle of the face (Fig. 1, 2). Under

by the action of the cutting head, the workpiece is bent in the direction of the force of the cutting force P, as a result of which an error is formed on the surface 2. processed by the cutter 4. If the direction of deformation

the part is an angle of / 3 with a tangent to it at the point of contact with the cutter 4 (Fig. 3), then at the deformation value I the change A of the radius of the part (machining error) will be

- $

1 + -sln / 9

21 cos / H (with arctgd + 2lsln / J

- one

(2)

From this dependence it follows that the processing error is maximum (),

if p -, that is, when the direction of the deformation is perpendicular to this tangent. The error A is minimal if / 3 0, i.e. when the direction of deformation is parallel to the tangent to the machined surface at the point of contact with the tip of the tool, whose position is adjusted in accordance with dependence (I). This dependence follows from FIG. 2, according to which h

jtga, where tg and p. In this case

one

21 I cos arctg-r

(3)

therefore, the component of the machining error of the round surface due to

(1 + 2 sin / - cos arctg "cosarctg

2T

(COS 8rCtg d + 2Tsln /) (1 C ° S ar ° t9 T)

time. This increases the accuracy of machining the round surface when the cutter and the cutting head are working together.

The frequency u of rotation of the workpiece is determined based on the allowable cutting speed, taking into account that it is equal to the sum of the peripheral speeds of the workpiece and the cutting head in the cutting zone. therefore

V1

- 1h

2l (g + RI)

(min)

(five)

where v is the cutting speed with a cutting head, m / min;

g is the radius of a circle inscribed in the profile of a multifaceted surface, mm;

R is the radius of the cutting head, m;

1 П2 / П1 - the ratio of the frequencies of rotation of the cutting head and the workpiece.

In addition, the frequency of rotational rotation of the workpiece when machining with a cutter 4 is determined by the dependence

um (min

-one

(6)

where v is the cutting speed when turning a cylindrical surface, m / min; D is the diameter of the workpiece, m.

the deformation of the workpiece under the action of the cutting head decreases in

rctg

2T

T)

(four)

With simultaneous machining of the part by the cutter 4 and the head 5, the rotation frequency of the workpiece is adjusted not more than the smaller of the two values determined from dependencies (5) and (6).

Claims (1)

Invention Formula The method of machining parts with round and multifaceted surfaces, according to which the parts report rotation around an axis, the round surface is machined with a cutter and at the same time the multi-faceted surface is machined with a cutting head, which is reported to rotate around its axis, consistent with in order to increase the accuracy of machining the round surface, the cutter is shifted relative to the plane passing through the axis of rotation of the part and the cutting head in the direction opposite to the direction of rotation details, while the angle "offset cutter is chosen from the ratio a - arctg R where Py and Pz are the radial and tangential components of the cutting forces acting from the cutting head on the part. Fi.Z