SU1151371A1 - Boring method - Google Patents

Abstract

BORING METHOD, in which the workpiece and rotating borschtang with an unbalanced bearing tool /////////////// L U /////// ///////// Nyu relative axial feed, characterized in that, in order to increase the accuracy when bore deep holes, the frequency of rotation of the boring bar is changed depending on its deformation along the depth of the bore hole and synchronously with the frequency of rotation of the boring bar changes the frequency of rotation of the workpiece under the condition that the speed is kept cutting constant. one

Description

U2.f

FIELD: machine tool industry.

There is a known boring method in which the relative axial feed 1 is reported to the workpiece and the rotating borscht with an instrument carrying an unbalanced mass.

The disadvantage of this method is the relatively low accuracy when bore deep holes.

The purpose of the invention is to improve the accuracy when bore deep holes.

To achieve this goal, according to the method of boring, in which the workpiece and the rotating borschtang with an instrument carrying an unbalanced mass communicate relative axial flow, the frequency of rotation of the borschtangi is changed depending on its deformation over the depth of the bore hole and synchronously with the frequency of rotation of the borschtangi change the frequency rotation of the workpiece from the condition that the cutting speed is kept constant.

A scheme for implementing the method as a process for performing interrelated actions is shown by the example of a hole bore with a cantilever mounted cutter.

FIG. 1 shows a diagram of an apparatus for carrying out the method; in fig. 2 and 3 - boring structures.

The method is carried out as follows.

The workpiece 1 is installed in the machine stem and the rotation from the regulated motor 2 is communicated to it. The cutter 3 is mounted in the borschtang 4 and the rotation from the adjustable engine 5 is communicated to it. The unbalanced mass 6 is fixed to the length of the console 3 approximately. The rotational speed of the boring rods 4 is chosen in such a way as to rationally reduce and then stabilize the elastic deformation of the boring bar 4, which is deformed under the influence of the cutting force and also when the depth p Astrochka. This deformation usually varies with changes in the material strength allowance, tool blunting, etc.

For this purpose, a strain gauge 7 is installed on the Borstedt 4, which through a comparative device 8 is inserted into a closed engine speed control system 5 containing a master 9 and a control 10 devices. Thus, this system provides control over the rotation frequency of the borschtangi and the function of its deformation over the depth of the bore. The system provides the specified deformation of the boring bar regardless of external factors, which increases the accuracy of processing.

The control of the rotational speed of the engine 5 leads to a change in the cutting speed.

To ensure a given cutting speed, sensors 11 and 12 are installed, which through summing device 13 are included in a closed-loop engine speed control system 2, which contains driver 14, which compares 15 and control device 16. In this way, the tool frequency is controlled as a function of the deformation of the boring bar, keeping it in the desired range of elastic deformation, and the frequency of rotation of the workpiece is controlled as a function of speed, ensuring optimum cutting speed.

During the machining process, under the influence of the cutting force F (Fig. 2), the boring bar is deformed. For partial or full compensation of the process load and deformation of the boring bar, the mass 6 is set at an angle При. When rotating the boring bar 4, the centrifugal force Fy of the unbalanced mass 6 partially compensates for the bar boring deformation by force F. The carriage 17 allows changing the mass setting radius 6 and the angle ot when setting up . The length of the console for installing mass 6 is slightly longer than the length of the console for installing the cutter 3 and makes these lengths co5 of the Merimshi. A sensor 7 mounted on the borschtang measures the bending deformation, as a function of which the rotational speed of the boring bar and the value of the centrifugal force Py are controlled.

Example. A clean bore hole with a diameter of D 60 mm, a depth of L 100 mm in parts made of corrosion-resistant steels (Qf 130-150 kgf / mm) is produced. Cutter material with VK6M alloy plate. Cutting modes: cutting speed V 123 m / min, feed S 0.15 mm / rev, t 0.5 mm, F 38 kgf, power Nb 0.76 kW (when using an unbalanced mass m 2H and located on radius e 0.02 m). To obtain centrifugal force, which largely compensates cutting force F (P ,, 30 kgf), it is necessary to inform the center of mass of the speed

 103.92 m / min

To obtain this speed, it is necessary to have a rotational speed of the boring bar.

n rpm

0 To obtain a given cutting speed, you must have a relative frequency of rotation of the two spindles.

Pg% - 652 rpm

Thus, to obtain a centrifugal force Fy 30 kgf and a cutting speed V 123 m / min, it is necessary to rotate the workpiece spindle in the direction of rotation of the bushing thread with the frequency

Pg By-n 175 r / min. Thus, with the given processing modes, the borschtang will perceive the force

P F-Fy 8kgs

When external influences change (allowance, mechanical properties of the material being processed, tool wear), the automatic control system will ensure, by controlling the frequency of rotation of the boring bar, permanent deformation of the boring bar. At the same time, the rotational speed of the workpiece will vary.

The proposed invention improves the accuracy of deep hole boring.

FIG. 2

Claims (1)

METHOD OF BORING, in which the workpiece and the rotating boring bar with a tool carrying an unbalanced mass, report the relative axial feed, characterized in that, in order to improve accuracy when boring deep holes, change the frequency of rotation of the boring bar depending on its deformation along the depth of the boring hole and synchronously with the rotational speed of the boring bars, the rotational speed of the workpiece is changed from the condition that the cutting speed is kept constant. FIG. /