RU2822491C1 - Method of processing flat and curved surfaces of die tooling with correction of tool wear and machine errors - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used for final milling of flat and curved surfaces of tooling and parts of machines under condition of constancy of interaction of section of the main cutting edge and allowance. Method includes use of end cylindrical or conical cutters with working part, at least part of surface of which is made curvilinear. Prior to processing, flat sample is processed at constant angles of cutter inclination till preset maximum allowable wear is achieved. After treatment of each layer, height dimensions of the treated surface are measured at least at four points and a roughness parameter. Curvilinear surface of the article is processed with correction of the trajectory of working strokes of the tool along the normal to the processed section of the curvilinear surface for the current length of the cutting path.

EFFECT: higher precision of final milling.

1 cl, 7 dwg, 5 tbl

Description

The invention relates to mechanical engineering and can be used for finishing milling of flat and curved surfaces of equipment and machine parts, provided that the interaction between the section of the main cutting edge and the allowance is constant. For example, clamping surfaces of dies, connector surfaces of crankcases, cylinder blocks of internal combustion engines, surfaces of dies of sheet material.

There is a known method for manufacturing screws with control of the shape of the cutting edges of the tool, including the use of a tool with shape-forming cutting edges, control of their shape, installation of the tool at an angle and at a distance to the screw workpiece with the imposition of the necessary kinematic connections on the tool and/or workpiece to carry out the cutting process, with In this case, they use a tool with a set of templates for its shaping edges, calculated for several installation parameters, control the shape of the cutting edges of the tool by the size of the gaps between the template and the cutting edges, evaluate the change in the shape of the cutting edges as the tool wears, and then change its installation or carry out preliminary correction of the cutting edges in accordance with the selected installation parameters, then the cutting process is carried out with new tool installation parameters. (RF patent 2293625, IPC V23S 3/16 (2006.01), V23S 3/32 (2006.01), published 02/20/2007). The method allows for periodic adjustments of the tool by monitoring changes in tool wear for processing screw grooves. The disadvantages of the method include the low accuracy of determining the correction values of adjustment parameters due to visual control of the measurement of the shape of the cutting edge of the tool during its wear.

There is a known hardware method for monitoring the condition of the cutting edges of single-edge, prefabricated multi-edge and axial tools in the process of single-edge and multi-edge machining, which includes measuring instantaneous electrical voltage values produced by a measuring transducer in the form of an electrical sensor, converting them into a digital signal using an analog-to-digital converter and comparing them between themselves. Based on the relative values of the eddy current sensor signal corresponding to each cutting edge, the position of the edges, integrity, amount of wear, axial and radial runout are assessed (RF patent 2320457, IPC V23V 25/06 (2006.01), B23Q 17/09 (2006.01), B23Q 17/ 22 (2006.01), publ. 03/27/2008). A similar method for measuring cutter wear by moving it in the wear direction until a vibroacoustic signal from an accelerometer installed on a calibrated probe appears (RF patent 2594051 MPK B23Q 17/09 (2006.01), B23С9/00, (2006.01), published 08/10/2016). The methods are used to improve the reliability and efficiency of tool condition monitoring, but are not used for further compensation to improve machining accuracy.

There are known devices for tracking the shape of the workpiece of various designs for computer-controlled machines. For example, a device for tracking the shape of a workpiece in the form of a bracket with a fixed tracking support in the form of a spherical surface. The disadvantage is the influence of vibrations on the recording element of the device (RF patent No. 2465104, IPC V23S 3/04, published on October 27, 2012), devices with contactless tracking by supplying compressed air into the gap between the nozzle and the part. The registration method records only significant shape deviations. The devices allow you to obtain measuring information about the shape of the flat surfaces being machined and are not designed for use when milling curved surfaces.

There is a known method for processing parts on CNC machines, which makes it possible to improve geometric accuracy, roughness and eliminate concentrations of contour surfaces of parts made of difficult-to-machine materials. The method is carried out by correction, carried out according to the wear of the cutter, the roughness value and the cutting path, revealed as a result of performing trial runs with a sharpened cutter on the first part and the serial one. (RF patent 2220821, IPC V23V 1/00 (2000.01), published 01/10/2004). The method does not provide for compensation based on deviations in the shape of the surface being processed and implements correction only for the contour surfaces of parts.

There is a known method for processing finishing milling of flat surfaces, in which the cutter is milled with an inclination towards the output ends of the cutting edges. (RF patent 2137575, MPK V23S 3/00 (1995.01), published on September 20, 1999) The method improves the quality of the machined surface and productivity, but does not provide for compensation for machine errors and wear of the cutting edges of the cutter during the milling process.

There is a known method for processing a blisk blade of a gas turbine engine with end mills on machines with numerical control, including milling the profile of the blade feather from the top of the blade to the radius of the transition to the hub, while the metal is removed alternately from the side of the trough and the back in rows measured along the height of the blade feather, wherein the width of the first line is chosen to be less than or equal to half the width of the subsequent line, and the width of subsequent lines is chosen to be equal to or less than the width of the previous line from the condition that the alternation does not lead to symmetrical removal of metal from the side of the trough and the back, with the exception of processing the butt section of the feather, and ensures the maximum rigidity of the blade blade being processed; also during the processing process, intermediate control of errors of the machined surface is carried out using a set of reference points obtained as a result of determining their actual coordinates by contact, based on the results of which the basic control program is changed taking into account random errors for processing according to the adjusted program, in this case, the correction of the control program and subsequent processing are repeated until the required accuracy is achieved, and the specified processing is carried out for each blisk blade. (RF patent No. 2689476, IPC V23S 3/18 (2006.01), published 05/28/2019). The method will allow, by alternating coordinate measurements, calculating tool correction values and processing with the found corrections, to improve the geometric accuracy of the blisk blade of a gas turbine engine. The disadvantages of the processing method include the complexity of finding tool path corrections, since to find them it is necessary to carry out alternating coordinate measurements of the blade with long-term milling operations. It should be noted that only systematic and not random errors can be compensated by shifting the tool path, as stated in the formula of this invention.

There is a known method for milling flat surfaces, which involves milling the surfaces of a workpiece with a tool with a cylindrical generating surface and a rectilinear generatrix, to which the main rotational motion and translational feed motion in the milling direction are imparted, while the tool is provided with an additional reciprocating feed motion in the direction of the rectilinear generatrix of the tool with a stroke length , not exceeding the difference between the projection of the milling width onto the plane passing through the tool axis and the length of the working part of the tool, while the speed of the reciprocating movement is set with no less than eight times the speed of the specified translational movement of the tool feed in the milling direction. (RF patent No. 2626519, IPC V23S 3/00 (2006.01), published 07/28/2017). The method makes it possible to increase the durability of the tool due to the constant displacement of the cutting edges relative to the cutting surface, but does not provide for correction of the trajectory of its movement to compensate for the wear of the cutting edges of the tool and machine errors.

The closest analogue is the chosen method for processing curved surfaces, which consists in the fact that the processing is carried out using cylindrical or conical end mills with a working part, at least part of the surface of which is made curved, and the processing is carried out by milling a section of the curved surface , satisfying the condition , wherein determined from the ratio:

Where - radius of curvature of the normal section of the working part of the cutter, passing through the axis of the cutter;

- radius of curvature of the normal section of the machined surface passing through the axis of the cutter;

- fin tolerance;

- feed per line;

- the current angle of deviation between the cutter axis and the tangent plane to the machined surface of the part at the point of contact between the cutter and the machined surface of the part;

- the maximum angle of deviation between the axis of the cutter and the tangent plane to the curved surface of the cutter.

(RF patent No. 2351441, IPC V23S3/16 (2006.01), V23S5/10 (2006.01), V23S5/14 (2006.01), published 04/10/2009).

The method is aimed at ensuring the processing of surfaces in a strictly defined section of the curve according to the condition of ensuring the tolerance value of the design position of the profile of the surface being processed. The processing method does not take into account the influence of tool cutting edge wear on the final precision of workpiece surface processing.

The technical problem to be solved by the invention is to increase the geometric accuracy of finishing milling of flat and curved surfaces, provided that the interaction between the section of the main cutting edge and the allowance is constant due to the correction of the tool path, compensating for machine errors and wear of the cutting edges during their service life.

This problem is solved by the fact that in the method of processing curved surfaces with cylindrical or conical end mills with a working part, at least part of the surface of which is made curved with a radius , before processing the stamping equipment, a flat sample is processed layer by layer at constant angles of inclination of the cutter until the specified maximum permissible wear is reached, after processing each layer, the height dimensions of the treated surface are measured at at least four points and the roughness parameter , calculate the deviations of the base plane from the adjustment size deviation from flatness , find the functions of changing the deviations of the machined surface along the length of the cutting path:

,

,

,

Where - functions for changing the deviation of the base plane from the setting size for the upper and lower sections of the cutting edge of the cutter;

- functions for changing the deviation from flatness for the upper and lower sections of the cutting edge of the cutter;

- functions for changing surface roughness for the upper and lower sections of the cutting edge of the cutter;

- variable cutting path length;

- an array of cutting path length values corresponding to the processed layers on the sample for the upper and lower sections of the cutting edge of the cutter;

- an array of deviation values of the base plane from the adjustment size of all processed layers for the upper and lower sections of the cutting edge of the cutter;

- an array of values of deviations from flatness of all processed layers for the upper and lower sections of the cutting edge;

an array of roughness parameter values for all processed layers for the upper and lower sections of the cutter cutting edge;

- layer numbers for the upper section of the cutting edge of the cutter ( );

measure with a selected step the straightness of movement of the machine supports along the X and Y coordinates within the dimensions of the processing area of the stamping equipment , , find the function of changing deviations from straightness of movement of machine supports along the length of the cutting path:

,

after which the curved surface of the die equipment is processed with correction of the trajectory of the tool’s working strokes by the amount normal to the machined section of the curved surface for the current length of the cutting path according to the following dependence:

Where - maximum deviation of the profile of the curved surface of the die equipment,

- minimum deviation of the profile of the curved surface of the die equipment,

.

Performing a method for processing curved surfaces with cylindrical or conical end mills with a working part, at least part of the surface of which is made curved with a radius , with preliminary processing of a flat sample with a milling cutter at a constant angle of inclination until a specified maximum permissible wear is achieved, and measurements of the specified characteristics of the sample surface after processing each layer, measurements of the straightness of movements of the machine supports within the dimensions of the processing area of the stamping equipment in combination with the output of functions for changing the deviations of the machined surface taking into account deviations from the straightness of the machine within the dimensions of processing the die equipment along the length of the cutting path with subsequent processing of the curved surface of the product with correction of the trajectory of the tool's working strokes by the value calculated from the given dependencies will make it possible to compensate for the influence of tool wear in various sections of the cutting edge and thereby increase the geometric accuracy processing.

An analysis of known technical solutions in this field of technology has shown that the method of processing flat and curved surfaces, subject to the constancy of the interaction between the section of the main cutting edge and the allowance with the correction of tool wear and machine errors, has features that are absent in analogues, and their use in the claimed set of essential characteristics allows you to obtain a new technical result.

The claimed technical solution is illustrated by drawings, where:

fig. 1 - diagram of geometric deviations of the processed flat base surface;

fig. 2 - a) processing sketches, b) measurement points for the height dimensions of the sample and a diagram for finding deviations from straightness;

fig. 3 - area where the coordinates of the profile of the processed material sample are located , spherical end mill without taking into account the machine error;

fig. 4 - machine for processing products with flat and curved die surfaces;

fig. 5 - graphs of changes in machine errors in the form of deviations from the straightness of movement, deviations from the straightness of a CNC milling machine;

fig. 6 - graph of total deviations , flat surface of the sample, taking into account machine errors before and after correction of the trajectory of the ball end mill.

fig. 7 - graphs of trajectory corrections spherical end mill of the flat surface of the die equipment: along the cutting path during the period of its durability.

A method for processing curved surfaces, which consists in the fact that the processing is carried out using cylindrical or conical end mills 1 with a working part, at least part of the surface of which is curved, and the processing is carried out by milling a section of the curved surface 2 with a radius . Before processing the stamping equipment, a flat sample 3 is processed layer by layer at constant angles of inclination of the cutter until the specified maximum permissible wear is reached, after processing each layer, the height dimensions of the treated surface 4 are measured at at least 4 points and the roughness parameter , calculate the deviations of the base plane 5 from the adjustment size , deviation from flatness , find the functions of changing the deviations of the machined surface along the length of the cutting path:

,

,

,

Where - functions for changing the deviation of the base plane from the setting size for the upper and lower sections of the cutting edge of the cutter;

- functions for changing the deviation from flatness for the upper and lower sections of the cutting edge of the cutter;

- functions for changing surface roughness for the upper and lower sections of the cutting edge of the cutter;

- variable cutting path length;

- an array of cutting path length values corresponding to the processed layers on the sample for the upper and lower sections of the cutting edge of the cutter;

- an array of deviation values of the base plane from the adjustment size of all processed layers for the upper and lower sections of the cutting edge of the cutter;

- an array of values of deviations from flatness of all processed layers for the upper and lower sections of the cutting edge;

an array of roughness parameter values for all processed layers for the upper and lower sections of the cutter cutting edge;

- layer numbers for the upper section of the cutting edge of the cutter ( );

The straightness of movement of the machine supports 6, 7 along the X and Y coordinates is measured with a selected step within the dimensions of the processing area of the stamping equipment , , find the function of changing deviations from straightness of movement of machine supports along the length of the cutting path:

,

after which the curved surface of the die equipment 7 is processed with correction of the trajectory of the tool’s working strokes by the amount normal to the machined section of the curved surface for the current length of the cutting path according to the following dependence:

Where - maximum deviation of the profile of the curved surface of the die equipment,

- minimum deviation of the profile of the curved surface of the die equipment,

.

The problem being solved is to increase the geometric accuracy of finishing milling of flat and curved surfaces, provided that the interaction between the section of the main cutting edge and the allowance is constant due to the correction of the tool path, compensating for machine errors and wear of the cutting edges during their service life.

As an example of a method for processing flat and curved surfaces of die equipment with correction of tool wear errors and machine errors, let us consider milling a flat surface with a spherical end mill. The probabilistic modeling method is used to calculate the tool correction. To use it, it is necessary to obtain information about the most likely location of the profile coordinates. With this approach, the probable maximum and minimum coordinate values are determined. The number of points along the length of the cutting path for constructing the model is selected based on the requirements for processing accuracy.

In fig. Figure 1 shows a diagram of the formation of geometric deviations during the finishing milling of a flat surface with a spherical end mill. At the starting point of the section of the inclined surface being processed, the forming element, as a result of reaching the coordinates of the beginning of the working stroke, has a size value along the coordinate .

In the first moments of cutting, the radial force deflects the cutter along the Y axis from this initial position on the machined surface area within the limits of , During processing of the sample surface, due to wear and vibration of the cutter, the position of the contact point of the cutter edges changes within the values , (Fig 3). These deviations naturally change along the length of the cutting path l. As a result, a sample surface with deviations in size and profile is formed.

The maximum position limit of the profile points of the machined surface is calculated along the length of the cutting path, according to the following mathematical relationship:

(1)

Where - function of changing deviations from straightness of the movable modules of the machine, mm.

- function of changing the deviation of the base plane from the adjustment size for the upper section of the cutting edge, mm,

- function of changing the deviation from flatness for the upper section of the cutting edge, mm;

- function of changing surface roughness for the upper section of the cutting edge, mm.

Minimum deviation of the profile of the curved surface of the die equipment when forming with the lower section of the cutting edge:

(2)

Where - function of changing deviations from straightness of the movable modules of the machine, mm.

- function of changing the deviation of the base plane from the adjustment size for the lower section of the cutting edge, mm,

- function of changing the deviation from flatness for the lower section of the cutting edge, mm;

- function of changing surface roughness for the lower section of the cutting edge, mm.

The considered correction method can be used for processing transitions of curved surfaces with slight curvature of the surface, cylindrical or conical end mills with a working part, at least part of the surface of which is curved, provided that the interaction between the section of the main cutting edge and the allowance is constant.

The correction value in each step of the tool movement path is taken to be the difference between the current value of the point position coordinates and its target value (the middle of the tolerance field for the dimensional accuracy indicator):

(3)

Where - maximum deviation of the reference plane from the nominal position of the sample plane.

- minimum deviation of the base plane from the nominal position of the sample plane.

Let's consider an example of processing a flat surface with a spherical end mill (Fig. 2), with an axis inclination angle to the machined surface of 45°.

The processing was performed on a Hedelius RS605 K20 five-axis CNC milling machine with a rotary table (Fig. 2a). Diameter of carbide ball end mill f. Sandvik Coromant 8 mm. The cutter reach is 70 mm. The cutters were fastened into the Shunk TENDO E Compact chuck. The tool runout in the chuck was 2-4 microns. The milling transition parameters correspond to the factory modes n - 7900 rpm; S =2000 mm/min; Sz=0.12 mm/tooth. The milling stitch pitch is 0.15 mm. The milling depth was selected based on the finishing milling conditions of 0.15 mm. Compressed air (P = 6 atm.) was used as a lubricant and coolant.

Measurements of the height dimensions of the processed sample were carried out using an altimeter f. Mahr Digimahr 817 SM, spherical tip diameter 2,000 mm (Figure 2 b) roughness parameters were determined by a mobile profiler M 400 f. Mahr, As a result of layer-by-layer processing of the material sample and measurements of the sample at nine points, a change in the following deviations was found:

- base plane from the setting size ;

- from flatness ;

- values .

Measurement of cutter wear on the flank surface was carried out using an MBS 2 stereomicroscope.

Table 1 shows the deviations from flatness, straightness and roughness parameter Rz of a flat material sample calculated from measurement data.

Table 1. Values of deviations from flatness, straightness and roughness parameter Rz of material samples processed with a ball end mill at an angle of 45°.

Cutting path
l Deviation of the reference plane from the adjustment dimension
Deviation from flatness
ΔZ min. ΔZ max. m mm mm µm mm mm 0 0.000 0.000 0 0.000 0.000 166,666 0.0035 0.044 4,842 -0.024 0.031 333.332 0.007 0.047 3.126 -0.020 0.034 499,998 0.025 0.011 2.435 0.017 0.033 666.664 0.01 0.036 1.935 -0.010 0.030 833.330 0.053 0.031 4,457 0.033 0.073 999,996 0.049 0.018 3.616 0.036 0.062 1166.662 0.07 0.044 3.58 0.044 0.096 1333.328 0.076 0.040 3.721 0.052 0.100 1499.994 0.068 0.029 5.575 0.048 0.088 1666.66 0.074 0.156 5,894 -0.010 0.158

Figure 3 shows the boundaries of the maximum ΔZmax. and the minimum ΔZmin finding the coordinates of the profile of the material sample along the length of the cutting path, calculated according to the data in Table 1 using formulas (1) and (2) without taking into account the error of the movable modules of the machine . The boundaries of the profile position decrease in a wave-like manner from a value of 0.07 mm at 400 m of the cutting path to 0.03 mm at 800 m of the cutting path and increase to a value of 0.06 mm when reaching 1500 m. Then an increase in the deviation is observed to 0.15 mm, which indicates a loss of precision in the milling process. Deviations from flatness also increase. Thus, over a length of 1600 m, dimensional accuracy is ensured within ±0.15 mm.

Table 2 shows the experimental data for measuring machine errors. The straightness of the movement of the calipers along the length of the processed material sample in the direction of the longitudinal and transverse movement of the tool was measured. The deviation is determined by the results of measurements with an electronic probe installed in the spindle of a CNC milling machine with a division value of 1 micron. Straightness deviations are a consequence of wear on the guide supports of a CNC milling machine (Fig. 4).

In fig. Figure 5 shows graphs of changes in deviations from straightness in the sample processing zone constructed from experimental data. Along the Y axis, the graph of changes in straightness has a parabolic shape and changes by 0.025 mm over a length of 250 mm. Along the X coordinate over a length of 100 mm, straightness changes linearly by 0.010 mm.

Table 2. Deviations from straightness of machine supports within the dimensions of the working area for processing the milling machine product.

X, mm 0 50 100 150 200 250 , µm 1 2 4 6 12 22 Y, mm 0 20 40 60 80 100 , µm 10 8 6 4 2 0

Table 3. Data on changes in the coordinates of the probable location of the boundaries of the profile of a flat sample of material, taking into account the errors of the machine system modules before and after the correction.

Path, l Before correction After correction ΔZmax ΔZmin ΔZmax ΔZmin m mm mm mm mm 0 0.000 0.000 -0.039 -0.039 166.66 0.010 0.010 -0.029 -0.029 166.66 0.011 0.066 -0.027 0.027 333.33 -0.010 0.044 -0.052 0.002 333.33 0.015 0.069 -0.027 0.027 499.99 0.027 0.043 -0.033 -0.017 499.99 0.052 0.068 -0.008 0.008 666.66 0.000 0.040 -0.045 -0.005 666.66 0.025 0.065 -0.020 0.020 833.33 0.043 0.083 -0.045 -0.005 833.33 0.068 0.108 -0.020 0.020 999.99 0.046 0.072 -0.038 -0.012 999.99 0.071 0.097 -0.013 0.013 1166.66 0.054 0.106 -0.051 0.001 1166.66 0.079 0.131 -0.026 0.026 1333.33 0.062 0.110 -0.049 -0.001 1333.33 0.087 0.135 -0.024 0.024 1499.99 0.058 0.098 -0.045 -0.005 1499.99 0.083 0.123 -0.020 0.020 1666.66 0.000 0.168 -0.109 0.059 1666.66 0.025 0.193 -0.084 0.084

Table 4. Regression models of changes in geometric parameters during the service life of spherical end mills, taking into account the error of machine modules.

Function designation Function Reliability of approximation R² = 0.9153

Table 5. Correction values for a flat surface of die equipment during the service life of a ball end mill

Cutting path, l m 0 166.66 333.33 499.99 666.664 833.33 999,996 Correction amount
, mm. 0 -0.0385 -0.042 -0.06 -0.045 -0.088 -0.084 Cutting path, l m 1166.66 1333.33 1499.99 1666.66 Correction amount , mm. -0.105 -0.111 -0.103 -0.109

These changes in the probable boundaries of the profile location are given in Table 3. Mathematical functions for changing the machine error are given in Table 4. In Fig. Figure 6 shows graphs of the position of the profile of the machined surface, taking into account the errors of the moving modules of the machine system. The graphs are plotted over a 166 m cutting path length, which corresponds to the cutting path of surface treatment of the product sample. The obtained limits for changing the position of the profiles make it possible to calculate the correction values of the CNC program for surface treatment along the cutting path of the tool, taking into account errors in tool wear, as well as the machine system. The correction values are given in Table 5.

In fig. 7 shows trajectory correction graphs , calculated using formula (3), Table 4 shows the mathematical correction function for the length of the cutting path. When adjusting the setting to the middle of the tolerance field, the geometric accuracy of the machined surface improves from 1.22 to 1.62 times along the machined surface (Cp increases from 1.12 to 1.82 according to the maximum values of deviations in the shape of the machined surface, Cp increases from the value c 1.74 to 2.14 according to the minimum values of deviations in the shape of the processed surface).

The problem being solved is to increase the geometric accuracy of finishing milling of flat and curved surfaces, provided that the interaction between the section of the main cutting edge and the allowance is constant due to the correction of the tool path, compensating for machine errors and wear of the cutting edges during their service life.

The method of processing flat and curved surfaces with cutters with a spherical cutting part, provided that the interaction between the section of the main cutting edge and the allowance is constant, can be implemented on existing equipment with numerical control using known tools, which meets the criterion of “industrial applicability”.

Claims (28)

A method for processing flat and curved surfaces of die tooling with correction of tool wear and machine errors, which consists in the fact that the processing is carried out using cylindrical or conical end mills with a working part, at least part of the surface of which is made curved, and the processing is carried out by milling a section of the curved surface , characterized in that before processing the stamping equipment, a flat sample is processed layer by layer at a constant angle of inclination of the cutter until the specified maximum permissible wear is reached, after processing each layer, the height dimensions of the treated surface are measured at at least four points and the roughness parameter , calculate the deviations of the base plane from the adjustment size , deviation from flatness , find the functions of changing the deviations of the machined surface along the length of the cutting path: , , , Where - functions for changing the deviation of the base plane from the setting size for the upper and lower sections of the cutting edge of the cutter; - functions for changing the deviation from flatness for the upper and lower sections of the cutting edge of the cutter; - functions for changing surface roughness for the upper and lower sections of the cutting edge of the cutter; - variable cutting path length; - an array of cutting path length values corresponding to the processed layers on the sample for the upper and lower sections of the cutting edge of the cutter; - an array of deviation values of the base plane from the adjustment size of all processed layers for the upper and lower sections of the cutting edge of the cutter; - an array of values of deviations from flatness of all processed layers for the upper and lower sections of the cutting edge; [Rz _i ] - array of roughness parameter values for all processed layers for the upper and lower sections of the cutter cutting edge; - layer numbers for the upper section of the cutting edge of the cutter ( ); measure with a selected step the straightness of movement of the machine supports along the X and Y coordinates within the dimensions of the processing area of the stamping equipment , , find the function of changing deviations from straightness of movement of machine supports along the length of the cutting path: , after which the curved surface of the product is processed with correction of the trajectory of the tool’s working strokes by the amount normal to the machined section of the curved surface for the current length of the cutting path according to the following dependence: Where - maximum deviation of the profile of the curved surface of the die equipment, which is determined from the condition: , in which - function of changing deviations from straightness of the movable modules of the machine, mm; - function of changing the deviation of the base plane from the setting size for the upper section of the cutting edge of the cutter, mm; - function of changing the deviation from flatness for the upper section of the cutting edge of the cutter, mm; - function of changing the surface roughness for the upper section of the cutting edge of the cutter, mm. - minimum deviation of the profile of the curved surface of the die equipment, which is determined from the condition: , in which - function of changing the deviation of the base plane from the setting size for the lower section of the cutting edge of the cutter, mm; - function of changing the deviation from flatness for the lower section of the cutting edge of the cutter, mm; - function of changing the surface roughness for the lower section of the cutting edge of the cutter, mm.