RU2399460C1 - Method for parts processing by cutting with anticipatory plastic deformation - Google Patents

Abstract

FIELD: technological processes. ^ SUBSTANCE: method relates to metal layer processing by means of its surface exposure to roll. Specified action is carried out due to development of deformation force by roll, equal in value and opposite in direction, in two diametrically arranged sections of part with further removal of allowance, value of which is identified by given dependence. ^ EFFECT: reduced energy intensity and increased resistance of tool. ^ 5 dwg, 1 tbl, 1 ex

Description

The invention relates to a technique for processing materials by cutting and can be used in turning of structural and hard-working, in particular stainless and heat-resistant steels, in order to reduce energy consumption, as well as increase tool life and improve surface shape.

In modern engineering, requirements for the quality of steels and alloys have substantially increased. Materials with special properties, including hard-to-work materials, in particular stainless and heat-resistant, are finding wider application. The main problem in the processing of such steels and alloys is their high tendency to hardening, which results in a high energy consumption of the cutting process, which leads to increased loads on the machine engine, low accuracy of the shape of the parts and reduced tool life.

A known processing method [USSR patent No. 1274852, class. B23B 1/00, publ. 12/07/1986], in which the forward deformation is carried out by a conical roller on the cutting surface, loaded with axial and radial forces. The disadvantage of this method is the incomplete preliminary hardening of the metal layer to be cut along the length of the cutting edge, which leads to increased loads on the machine engine as a result of increased energy consumption and reduced resistance of the cutting tool, as well as the formation of shear stresses that create part shape errors.

A known processing method [USSR patent No. 1634365, class. B23B 1/00, publ. 02.15.1991], in which the processing scheme with advanced deformation is solved by using a combined tool on one holder. The disadvantage of this method is asymmetric loading, leading to errors in the shape of the parts, and increased heating of the tool due to the presence of sliding friction, leading to a decrease in its durability.

A known processing method [patent GDR No. 205633, class. B23B 1/00, B23P 25/00, publ. 04/01/1984], in which the preliminary deformation is carried out by the use of a clamping element. The disadvantage of this method is asymmetric loading, leading to errors in the shape of the parts, and an increased load on the tool due to counter deformation forces, leading to a decrease in its durability with a comparable energy intensity of the cutting process.

The closest in technical level is the method of processing by cutting with advanced plastic deformation of the metal layer by applying a roller to its surface [USSR patent No. 1535672, cl. B23B 1/00, publ.

01/15/1990]. The disadvantage of this method is the asymmetric loading of the part with a deforming roller, which leads to increased errors in the shape of the parts, as well as incomplete preliminary hardening of the cut metal layer, which leads to uneven load on the cutter along the length of the cutting edge, which reduces the resistance of the cutting tool and does not reduce energy consumption, which causes an increased load on the machine engine.

Thus, the known methods of processing parts by cutting with advanced plastic deformation do not allow for high accuracy in the shape of the parts, normal tool life and acceptable energy consumption of the cutting process, which determines the normal load on the machine engine.

In the face of increased demands on product quality, an important task is to create a new processing method that would ensure high accuracy of the part shape, normal tool life and acceptable energy consumption of the cutting process, which determines the normal load on the machine engine, in a wide range of removable stock.

The technical result is the creation of a new method of processing parts by cutting with advanced plastic deformation in order to reduce the energy consumption of the cutting process, which determines the normal load on the machine engine, as well as to increase tool life and improve surface shape.

The technical result is achieved by the fact that in the method of cutting with advanced plastic deformation of the metal layer by acting on the surface of the roller with the roller, this effect is achieved by creating a roller of equal magnitude and opposite in direction of the deformation force in two diametrically located parts of the part with subsequent removal of the allowance, the value which is determined by the dependence:

t≤h _cm + h _n ,

where t is the removed allowance, mm;

h _cm - crushing depth, mm;

h _n - the depth of the riveted layer, mm

Figure 1 shows the processing scheme by which this method is implemented, figure 2 shows the dependence of cutting power on the depth of the deformed layer, figure 3 shows the dependence of radial runout after running on the depth of the deformed layer, figure 4 shows the dependence of taper on the depth of the deformed layer, in Fig.5 - the dependence of the efforts on the cutter on the depth of the deformed layer.

The proposed method is implemented with advanced deformation of the workpiece surface 1 of the workpiece 2 by rollers 3, located opposite in the plane 4 with the application of equal in size and opposite in the direction of the deformation force, and the subsequent cutting of the metal layer with a cutter 5. The size of the removed allowance is assigned as follows:

t≤h _cm + h _n , (1)

where t is the removed allowance, mm;

h _cm - crushing depth, mm;

h _n - the depth of the riveted layer, mm

The processing according to the proposed method by exposing a roller in two diametrically located parts of the part with an equal in magnitude counter-force of deformation can significantly reduce energy costs compared with the prototype with an equal depth of the deformed layer. The radial forces, which make up a significant part (about 70%) of the force, are mutually compensated, and the power plant of the machine is loaded only with tangential and axial forces.

As a result of accelerated deformation according to the proposed method, excess internal energy is accumulated in the hardened metal layer. When exposed to the hardened layer with a cutter, the necessary energy for the destruction of the metal in this case decreases by the amount of stored internal energy. As a result, the load on the cutting tool is reduced and, as a result, its resistance is increased.

The impact of the roller in two diametrically located parts of the part with an equal opposite deformation force allows to reduce the radial runout of the original workpiece immediately before removing the allowance, which significantly increases the uniformity of the load on the cutting tool and, accordingly, increases its durability.

In addition, with the indicated effect, the deforming rollers perform the function of a movable support, which reduces the amount of deflection under the action of cutting forces and, as a result, reduces the shape errors of the part.

Compliance with condition (1) is necessary based on the following considerations. Austenitic class steels are characterized by a high tendency to hardening, and therefore the physicomechanical properties of the deformed and undeformed metal layers differ very significantly. To ensure the possibility of achieving this goal, it is necessary to ensure a relatively uniform load on the cutter along the length of the cutting edge. This is only possible if the cutting depth does not exceed the depth of the riveted layer:

t'≤h _n , (2)

where t 'is the depth of cut, mm;

h _n - the depth of the riveted layer, mm

When a workpiece is exposed to a roller, its diameter decreases due to crushing of microroughness protrusions and compaction of the dislocation by a value of 2 · h _cm , where h _cm is the crushing depth, mm.

Thus, the minimum machining allowance consists of the depth of crushing and the depth of the riveted layer (1). Under this condition, the tool life increases.

The implementation of the proposed method is carried out in the following steps.

The necessary size of the removed allowance for this operation is assigned.

The roughness of the initial surface is determined by Rz. For engineering calculations, it is conventionally accepted:

h _cm = 0.5 · Rz, (3)

where h _cm is the depth of collapse, mm;

Rz is the surface roughness, mm.

From the formula (1), the required depth of the riveted layer is determined:

h _n ≥th _cm

where t is the removed allowance, mm;

h _cm - crushing depth, mm;

h _n - the depth of the riveted layer, mm

According to known dependencies, the necessary deforming force is determined, and the load on the power plant of the machine is checked. If necessary, the size of the removed allowance is reduced.

The cutter is installed to remove the assigned allowance.

The deforming rollers are loaded with the necessary force, and combined cutting is carried out with advanced plastic deformation, which leads to a decrease in the energy intensity of the process, as well as an increase in tool life and improved surface shape.

Example. The batch of cylindrical parts was processed using the proposed method on a 1M63 turning screw cutting machine (material - steel 12X18H10T, HB 190-210, Rz 200, D = 200 mm, L = 400 mm). Surface plastic deformation was carried out by non-contact cylindrical rollers (material - steel ШХ15, HRC 62-64, D = 52 mm, L = 18 mm). The cutting was carried out with a through cutter with mechanical fastening of the VK8 plate with a main angle of 45 ° in plan. The processing speed was 80 m / min, a longitudinal feed of 0.4 mm / rev. Processing was carried out in the range of values of the removed allowance from 0.1 to 1.5 mm per side.

The processing results of the proposed method were evaluated by measuring the geometric parameters of the parts and the efforts on the cutter according to the method of natural thermocouple.

The research results showed that the energy intensity of the process compared to the prototype decreased by 40% (figure 2, table.), Which characterizes the reduction in the load on the machine engine; the load on the cutter decreased by 40% (Fig. 5, table) and its unevenness (Fig. 3, table), which characterizes an increase in its resistance; and also improved the shape of the surfaces of the parts (figure 4, table.).

In addition, the proposed method allows to achieve a reduction in production costs by reducing the cost of energy consumed. The proposed processing scheme due to these factors allows to reduce the load on the engine and the working parts of the machine, which reduces its wear. Advanced plastic deformation has a beneficial effect on the quality of the surface layer after processing: microgeometry improves, the structure becomes denser and microhardness increases slightly, which increases the operational characteristics of the parts.

Claims (1)

A method of processing by cutting with advanced plastic deformation of a metal layer by exposing it to a surface with a roller, characterized in that the said effect is achieved by creating an equal in size and opposite in direction direction of deformation force in two diametrically located parts of the part with subsequent removal of the allowance, the value of which is determined according to
t≤h _cm + h _n , where
t - removable allowance, mm;
h _cm - crushing depth, mm;
h _n - the depth of the riveted layer, mm

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