SU1060349A1 - Method of machining curvilinear surfaces - Google Patents

Abstract

1. METHOD FOR TREATING CURVES; SURFACE SHEELS, such as turbine blades with radial end mills on machines with numerical programmed control, in which the inline milling of the internal profile is performed, the part is rotated around its axis and the outer profile is milled, differing from the amp; in order to increase the productivity and quality of processing, in the process of milling the inner and outer profiles, the part is discretely rotated on a line so that in the cross section on the first line the axis the cutter was located normal to the surface of the workpiece, and on the next htttHX line, the axis of the cutter is at an angle to the normal equal to ± L5Rcos pmfonnQ, V L r-2LRcoe / where R is the radius of curvature of the surface in this area, mm; COS O CCOS- / -2arccoe HH "5} i i r ICR + fctR U L Rtl ± r, where t is the stock allowance, mm; G - the radius of the cutter, mm; height of irregularities after; processing, mm.

Description

2. The method according to claim 1, characterized in that the first line in the longitudinal section of the part is the axis

cutters have at an angle to the norm-) to the surface, equal to 5 10 °.

one

The invention relates to line-milling by end-radius mills of special products that have complex curvilinear surfaces, for example, the working profile of turbine blades on machine tools with numerical program control.

There is a method of processing curved surfaces, for example, turbine blades with radius cutters on CNC machines, in which line milling of an internal profile is carried out, the part is turned around its axis and the external profile i is milled,

However, the processing method is not sufficiently productive and does not provide the desired quality. The cutting conditions on the individual sections of the surface to be treated are unequal and therefore the cutting modes. the exodus of the worst begins. good cutting conditions, and in the rest of the areas are underestimated. In addition, hazardous vibrations occur in certain areas, which adversely affect the quality of the treatment as a whole. The constant position of the cutter during machining leads to the fact that the tool in some areas works in an unfavorable drilling mode, which leads to its premature failure, deterioration of the surface layer quality, and wear of the machine mechanisms. The milling cutter operates with a predominantly cylindrical cutting part, which wears out more intensively than a spherical one, and therefore the tool life is not high enough. With the same cutter deformations, in certain areas the deviations from the nominal position of the profile are different. This adversely affects the accuracy of the surface obtained. The inner and outer profiles are milled on different operations in two devices of different design, which also leads to loss of accuracy and an increase in auxiliary and preparatory final time,

The purpose of the invention is to increase the productivity and quality of processing.

The goal is achieved according to the method of processing curved surfaces, for example, turbine blades with radial end mills on CNC machines, in which line milling of the internal profile is performed, the part is turned around its axis and the external profile is milled in the internal and external profile milling process perform discrete rotation

details n.a line so that in the cross section on the first line the axis of the cutter was located normal to the surface of the workpiece, and on subsequent lines

the axis of the cutter is located at an angle to the normal equal to

iLJRcosjf

pi: arccos

ilVRMlR

0 where R is the radius of curvature of the surface in this area, mm;

, -r „RvttRjf + L -r

cos arccos-- j; - ag

 L-RTttr

t- - stock blank, mm;

 - the radius of the cutter, mm;

j; - height of irregularities after

0; processing, mm.

On the first line in the longitudinal section of the part, the axis of the cutter is placed at an angle to the normal to the surface, equal to 5-10,

5 In FIG. 1 shows the scheme

proposed processing; FIG. 2 is a view A of FIG. 1; Fig, 3 - surface treatment circuit with a radius of R; FIG. 4 is a view B of FIG. 3

0 To implement the method, the workpiece, for example, a turbine trap, is installed in a rotary device, the rotation of which is carried out according to a program from a numerical control device (CNC). At the same time, the tool and the workpiece are positioned in a longitudinal direction. the billet section, their axes were the angle S-lo,

The inclination of the cutter relative to the machined surface in a longitudinal section at an angle of not less ensures that the cutter does not work in an unfavorable drilling mode, at the same time this angle

must not exceed 10, as this will lead to an increase in vibrations and the cylindrical part of the cutter, which wears heavily when working. When milling the first line in cross section, the axis of the cutter is normal to the surface of the workpiece. After processing the first line, the workpiece turns with a step to the line and the tool is positioned so that its axis is located to the normal to the surface at an angle determined by the formula tUTftcosy ft apccos-pr -U TRMLRCOS where is the curvature radius of the workpiece surface this area, mm; LtR4U (.RltlR if-L arccos ----- 2arcco5 --- 2RL - CR + ttR U t - stock blank, mm; t - cutter radius, mm; R-jt - height of irregularities after machining, mm (upper The ki correspond to the machining of the outer profile, and the lower ones - the inner one. During further processing after the freezing of each line, the button is turned in steps of the line, each tool being oriented at an angle (to the normal to the surface. The processing ends after turning the workpiece on 360. Turn of a mill on an angle (b provides simultaneous operation of at least two teeth of a mill, t, e, dir m face or counter-milling, which increases the smoothness of the tool, reduces vibrations and improves the cutting mode.The reduction of vibrations with the proposed method of orienting the cutting tool is explained by a decrease in the amplitude of oscillations of the total cutting force attributable to all the teeth involved in the cutting process. The orientation of the cutting method proposed by the method makes it possible to achieve relatively identical cutting conditions for different parts of the surface to be treated. This stabilizes the milling process and improves the accuracy and quality of the surface layer. The treatment of the internal and external profiles is carried out in one installation in one device. This increases the accuracy of processing, reduces auxiliary and preparatory-final time, allows the use of multi-station equipment.

(picture 2

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Claims (2)

154) 1. METHOD FOR PROCESSING CURVILINEAR SURFACES, for example, turbine blades with end radius mills on numerically controlled machines, in which line milling of the internal profile is carried out, the part is rotated around its axis and the external profile is milled, characterized in that, in order to increase productivity and processing quality, in the process. All milling of the internal and external profiles carries out discrete rotation of the part onto the line so that in the cross section on the first line the cutter axis is normal to the workpiece surface, and on subsequent lines the cutter axis is at an angle to the normal equal to tb5 Rcos X 'Rcos / where R is the radius of curvature of the surface of the plot, mm; R ^, 4t ' ² -r' ² 2RL where i is the stock blank, G is the radius of the cutter, mm; R _z - the height of the roughness of the processing, mm “G mm; after 2. The method according to π. 1, characterized in that on the first line in the longitudinal section of the part, the axis of the cutter is positioned at an angle to the norm - | whether to a surface equal to 5 10 °.