A method for controlling the area of multiple inner surface cutting layers of a large titanium alloy component during turning

Abstract

The application discloses a method for controlling the areas of multiple inner surface cutting layers of a large titanium alloy component, which comprises four steps, i.e., a calculation method for the residual cutting layer area of the inner surface, influence characteristics of the machining inclination angle on the cutting layer area, a cutting layer area consistency analysis and evaluation method, and a process design method and process scheme for the cutting layer area consistency; the method is proposed to control the areas of the inner surface cutting layers of the large titanium alloy component, and the method is based on the machining inclination angle change between the cutter and the machining surface when the inner surface of the large titanium alloy component is turned and the influence of the machining inclination angle change on the residual cutting layer area of the machining surface, the calculation method for the cutting layer area of the inner surface of the component and the consistency of the cutting layer area is proposed, the highest consistency of the cutting layer areas of the multiple machining surfaces is taken as a design target, and the process design scheme for the inner surface of the large titanium alloy component is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of titanium alloy component cutting, in particular to a method for controlling the cutting layer area of multiple inner surfaces of a large titanium alloy component. BACKGROUND

[0002] At present, as a force-bearing and containment component of an aviation transmission system, a large titanium alloy component has the characteristics of local thin wall weakness, high dimensional accuracy and high machining surface quality requirement, and the cutting stability and machining quality of the component have an important influence on the service performance of the transmission system. When turning the inner surface of such a component, the component structure and rigidity are variable under the action of cutting force, the stiffness field and residual stress rebalancing of each process and the machining deformation have uncertainty, and the machining error and machining quality consistency are difficult to accurately control.

[0003] The cutting layer area not only affects the cutting deformation, but also directly affects the cutting force and machining surface topography, and is an important process variable for controlling the cutting stability and machining quality. When continuously cutting multiple inner surfaces of a large titanium alloy component using a vertical turning machining center, the cutting tool posture and feed path cannot be changed in a large range due to the constraints of the machine tool and the component structure and rigidity, and there is a large difference between the machining inclination angle of the cutting tool and the component surface, so that the cutting layer areas of the multiple machining surfaces are not equal, resulting in large variation of the cutting force load, and the cutting stability and machining quality are difficult to effectively control.

[0004] The existing cutting layer parameter solving and process design method for turning a large conical surface component only controls the cutting force and machining quality indicators of a single machining surface, ignores the influence of the matching relationship between the machining inclination angle, tool angle and cutting parameters on the cutting layer area of multiple machining surfaces, and cannot meet the requirements of the cutting layer area consistency and machining quality consistency of multiple machining surfaces of the component, so it is necessary to optimize the cutting layer parameter and turning process design method for turning a large titanium alloy component. SUMMARY

[0005] The present application aims to provide a method for controlling the cutting layer area of multiple inner surfaces of a large titanium alloy component to solve the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for controlling the cutting layer area of multiple inner surfaces of a large titanium alloy component, comprising the following steps:

[0007] Step one, calculate the area of residual cutting layer of inner surface turning: determine the inner surface structure of titanium alloy component, cutting layer parameters and its feed path, set the component inner cylindrical surface with tool cutting processing inclination angle α of 0°, the component inner conical surface with processing inclination angle α of 34.6° and the component small end bottom surface with processing inclination angle α of-90°, calculate the angle between tool main cutting edge, vice cutting edge and tool feed speed, calculate tool working main deflection angle and working vice deflection angle, confirm that the cutting layer area of cutting component inner cylindrical surface, inner conical surface and small end bottom surface is affected by nominal cutting area and residual cutting layer area;

[0008] Step two, analyze the influence characteristics of processing inclination angle on cutting layer area: using the same tool, keeping the posture angle of tool and titanium alloy component axis unchanged, turning the inner surface of the component with the same cutting parameters, the cutting layer area of the inner cylindrical surface with processing inclination angle of 0° and the small end bottom surface with processing inclination angle of-90° is equal, using the matching tool to turn the inner surface of the component with different processing inclination angles, the cutting layer area with high consistency can be obtained;

[0009] Step three, analyze and evaluate the consistency of cutting layer area: obtain turning tools with tool nose angle of 80° and 55°, cutting layer area of turning inner surface with different processing inclination angles, the calculation and evaluation method of turning component inner surface cutting layer area consistency is:

[0010]

[0011] Wherein, δ AD is the consistency evaluation index of cutting layer area, i and j are different component inner surfaces respectively, A Dmi and A Dmj are the nominal cutting layer area of inner surfaces i and j respectively, A Dhi and A Dhj are the residual cutting layer area of inner surfaces i and j respectively, A Di and A Dj are the cutting layer area of inner surfaces i and j respectively, and A Dj is less than A Di ;

[0012] The smaller the evaluation index δ AD , the higher the consistency of turning component inner surface cutting layer area;

[0013] Step four, confirm the consistency of cutting layer area: set the target of the highest consistency of turning component inner surface cutting layer area, take the allowable cutting layer area of turning component inner surface cutting force and the cutting interference of tool as constraint conditions, take the initial main deflection angle of tool, tool nose angle, tool nose arc radius and per revolution feed as variables, obtain the consistent results of turning large titanium alloy component inner surface for turning component inner surface with different processing inclination angles.

[0014] Further, in step one, the angles κ f , κ s ' between the main cutting edge s, the minor cutting edge s' and the tool feed direction v s respectively are κ s = 270° - (α + κ r0 ), κ s ' = 270° - (α + κ r0 + ε r );

[0015] wherein α is the machining inclination angle, κ r0 is the initial main offset angle of the tool, and ε r is the tool nose angle.

[0016] Further, in step one, the working main offset angle κ r and the working minor offset angle κ r ' are respectively:

[0017]

[0018] Further, in step one, the cutting layer area A D of the inner cylindrical surface, the inner conical surface and the small end bottom surface of the cutting member is affected by the nominal cutting area A Dm and the residual cutting layer area A Dh ;

[0019] A D = A Dm - A Dh , A Dm = f x a p ;

[0020] wherein f is the feed per revolution of the workpiece, and a p is the cutting depth.

[0021] Further, when the tool nose radius is 0, the residual cutting layer area is:

[0022] -90° < α < 90° - (κ r0 + ε r ) and 90° - κ r0 < α < 90°.

[0023] Further, when the tool nose radius is greater than 0, and f > 2r ε sin κ r ', the residual cutting layer area is:

[0024]

[0025] wherein h max1for f > 2r ε sin κ r r ε for f > 2r

[0026] Further, for f > 2r ε sin κ r r

[0027]

[0028] for f > 2r max2 r ε sin κ r r

[0029] Further, in step two, based on the step one, the cutting layer area with different machining inclination angles of the inner surface is obtained, wherein the inner diameter of the titanium alloy component is 484mm to 824mm, the machining inclination angles of the large end inner cylindrical surface, the inner conical surface and the small end bottom surface of the component are 0°, 34.6° and -90° respectively, the initial main deflection angle κ r0 of the tool is 95°, the tool nose angle ε r is 80°, the tool nose radius is 0, and the cutting depths a p are 0.2mm, 0.4mm and 0.6mm respectively.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] (1) The present application discloses the influences of the machining inclination angle, the tool working main deflection angle, the working vice deflection angle, the tool nose radius, the feeding direction, the per-rotation feeding amount and the cutting depth on the residual cutting layer area and the actual cutting layer area in the process of turning the inner cylindrical surface, the inner conical surface and the small end bottom surface of the large titanium alloy component, solves the problem that the existing process design method ignores the change of the inner surface machining inclination angle to cause the change of the cutting layer area, and solves the problem that the cutting layer areas of the multiple inner surfaces are inconsistent.

[0032] (2) The present application can be used for the tool angle selection, the process scheme design and the machining surface morphology and cutting force calculation of the turning of the large titanium alloy component, and provides a basic model and a process method for realizing the efficient and high-stability turning machining of the large titanium alloy component. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the flow chart of the method for controlling the cutting layer area of the inner surface of the large titanium alloy component of the present application;

[0034] Figure 2 is the schematic diagram of the instantaneous cutting layer of the turning of the inner surface of the large titanium alloy component of the present application;

[0035] Figure 3 Fig. 1 is a schematic diagram of the tool angle of 0 degree for turning large titanium alloy components according to the present application;

[0036] Figure 4 Fig. 2 is a schematic diagram of the tool angle of 34.6 degrees for turning large titanium alloy components according to the present application;

[0037] Figure 5 Fig. 3 is a diagram of the tool angle of -90 degrees for turning large titanium alloy components according to the present application;

[0038] Figure 6 Fig. 4 is a schematic diagram of the residual cutting layer for turning the inner surface of large titanium alloy components according to the present application;

[0039] Figure 7 Fig. 5 is a cutting layer area broken line graph for turning the large end inner cylindrical surface and the small end bottom surface according to the present application;

[0040] Figure 8 Fig. 6 is a cutting layer area broken line graph for turning the inner conical surface according to the present application;

[0041] Figure 9 Fig. 7 is a diagram of the cutting layer area varying with the machining inclination angle for different tools according to the present application;

[0042] Figure 10 Fig. 8 is a cutting layer area broken line graph for the cutting depth a p of 0.15 mm according to the present application;

[0043] Figure 11 Fig. 9 is a cutting layer area broken line graph for the cutting depth a p of 0.80 mm according to the present application;

[0044] Figure 12 Fig. 10 is a flow chart of the process design method for the inner surface cutting layer area consistency of large titanium alloy components according to the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0046] Embodiment:

[0047] Referring to Figures 1-12 , the present application provides a technical solution: a method for controlling the cutting layer areas of multiple inner surfaces of large titanium alloy components;

[0048] In order to realize the accurate control of the turning inner surface cutting layer area and cutting force of large titanium alloy components, a turning inner surface cutting layer area solving model is established, the influence characteristics of the machining inclination angle and tool parameters of the large titanium alloy component inner surface on the cutting layer area are revealed, the turning inner surface cutting layer area consistency evaluation and process design method of large titanium alloy components is proposed, and the process design scheme of the large end inner cylindrical surface, inner conical surface and small end bottom surface of the titanium alloy component is obtained.

[0049] 1. A method for solving the residual cutting layer area of the inner surface of turning

[0050] The inner surface structure, cutting layer parameters and tool feed path of the large titanium alloy component are shown in Figure 2 According to Figure 2 , the work angle of the component inner cylindrical surface with tool cutting machining inclination angle α of 0°, the component inner conical surface with machining inclination angle α of 34.6° and the component small end bottom surface with machining inclination angle α of -90° is shown in Figures 3-5

[0051] Figures 3-5 In the formula, s is the main cutting edge, s' is the auxiliary cutting edge, ε r is the tool nose angle, κ r0 is the initial main offset angle of the tool, κ r0 ' is the initial main offset angle of the tool, κ r is the main offset angle of the tool during work, κ r ' is the auxiliary offset angle of the tool, κ s is the angle between the s edge of the tool and the feed direction in the counterclockwise direction, κ s ' is the angle between the s' edge of the tool and the feed direction in the counterclockwise direction, α is the machining inclination angle, n is the spindle speed of the machine tool, f is the feed per revolution of the workpiece (large titanium alloy component), v f is the feed speed, v fs is the feed speed in the direction of the s edge extension line, v fs ' is the feed speed in the direction of the s' edge extension line, v f ' is the feed speed between the s edge and the s' edge extension line, a p is the cutting depth, h D is the cutting layer thickness, b D is the cutting layer width, h max is the maximum residual height without considering the tool nose radius, ε r is the tool nose angle, r ε is the tool nose radius.

[0052] According to Figures 3-5 , the angles κ f , κ s ' between the tool main cutting edge s, auxiliary cutting edge s' and tool feed speed v s are respectively: ​

[0053] κ s = 270° - (α + κ r0 ) (1)

[0054] κ s ' = 270° - (α + κ r0 + ε r ) (2)

[0055] From Figures 3-5 and equation (1), equation (2), the tool working main offset angle κ r and working minor offset angle κ r ' are respectively:

[0056]

[0057] From Figure 2 and equation (1) - equation (4), the cutting layer area A D of the inner cylindrical surface, inner conical surface and small end bottom surface of the cutting member is affected by the nominal cutting area A Dm and the residual cutting layer area A Dh .

[0058] A D = A Dm - A Dh , A Dm = f x a p (5)

[0059] When the tool tip arc radius is 0, the residual cutting layer area is:

[0060]

[0061] -90° < α < 90° - (κ r0 + ε r ) and 90° - κ r0 < α < 90° (7)When the tool tip arc radius is greater than 0, and f > 2r ε sin κ r ', the residual cutting layer area is:

[0062]

[0063] When the tool tip arc radius is greater than 0, and f ≤ 2r ε sin κ r ', the residual cutting layer area is:

[0064]

[0065] By formula (1) - formula (11), the posture angle of the tool and the workpiece axis is kept unchanged, and the same cutting parameters are used to turn the inner surfaces of different components, although the nominal cutting layer areas are the same, but affected by the machining inclination angle, the tool nose angle, the tool nose radius, the tool working main offset angle and the working vice offset angle, the cutting layer areas are not equal.

[0066] 2. Influence characteristics of machining inclination angle on cutting layer area

[0067] By formula (1) - formula (7), the cutting layer areas of the inner surfaces with different machining inclination angles are obtained, as shown in Figure 7 、 Figure 8 . Among them, the inner diameter of the titanium alloy component is 484mm to 824mm, the machining inclination angles of the large end inner cylindrical surface, the inner conical surface and the small end bottom surface of the component are 0°, 34.6° and -90° respectively, the initial main offset angle κ r0 of the tool is 95°, the tool nose angle ε r is 80°, the tool nose radius is 0, and the cutting depths a p are 0.2mm, 0.4mm and 0.6mm respectively.

[0068] By Figure 7 、 Figure 8 , using the same tool, keeping the posture angle of the tool and the workpiece axis unchanged, and using the same cutting parameters to turn the inner surfaces of the components, although the large end inner cylindrical surface, the inner conical surface and the small end bottom surface have the same nominal cutting layer area, the cutting layer area of the inner conical surface is not equal to the cutting layer area of the inner cylindrical surface and the small end bottom surface.

[0069] Comparing Figure 7 、 Figure 8 , the difference between the cutting layer areas and the nominal cutting layer areas of the inner surfaces with different machining inclination angles is obviously different.

[0070] It is also found that the cutting layer areas of the inner cylindrical surface with a machining inclination angle of 0° and the small end bottom surface with a machining inclination angle of -90° are equal. The reason is that the tool with an initial main offset angle κ r0 of 95°, a tool nose angle ε r of 80° and a tool nose radius of 0 has the same working main offset angle and working vice offset angle when cutting the inner cylindrical surface and the small end bottom surface. This result shows that under certain conditions, using appropriate tools to turn the inner surfaces of components with different machining inclination angles, cutting layer areas with high consistency can be obtained.

[0071] 3. Analysis and evaluation method of cutting layer area consistency

[0072] By formula (1) - formula (7), the cutting layer areas of the inner surfaces with different machining inclination angles are obtained, as shown inFigure 9 , Figure 10 , Figure 11 As shown.

[0073] Depend on Figure 9 When the machining tilt angle α is in the range of -90° to 90°, if the machining tilt angle, the initial principal cutting edge angle of the tool and the tool tip angle do not satisfy equation (7), there is an interference area that the tool cannot cut. The size of this interference area is related to the selected tool angle.

[0074] Depend on Figure 10 When the cutting depth a p When the feed rate is 0.15mm, cutting the inner surface of components with different machining inclination angles using cutting tools at different angles results in varying degrees of difference in the characteristics of the cutting layer area as a function of feed rate per revolution, despite the small area being the cutting layer area. The difference is smaller when cutting the inner cylindrical surface at the large end, while the difference is larger when cutting the inner conical surface and the bottom surface at the small end.

[0075] Depend on Figure 11 When the cutting depth a p When the thickness is 0.80mm, the cutting layer area varies little with the feed per revolution when cutting the inner surface of components with different machining inclination angles using cutting tools at different angles.

[0076] Based on the above analysis results, the method for calculating and evaluating the consistency of the cutting layer area on the inner surface of turned components is as follows:

[0077]

[0078] In equation (12), δ AD The area of ​​the cutting layer is used as the consistency evaluation index, where i and j are the inner surfaces of different components, and A is the area of ​​the cutting layer. Dmi A Dmj The nominal cutting layer areas of inner surfaces i and j are respectively, A Dhi A Dhj The residual cutting layer areas of inner surfaces i and j are respectively, A Di A Dj Let A and J be the cutting layer areas of the inner surfaces i and j, respectively, and A Dj Less than A Di .

[0079] Based on equation (12), the evaluation index δ AD The smaller the value, the higher the uniformity of the cutting layer area on the inner surface of the machined component. This formula can be used for collaborative process design and process scheme evaluation of multiple machined surfaces of machined components to improve the surface quality of the machined components.

[0080] 4. Process design methods and process schemes for achieving uniform cutting layer area

[0081] With the formula (1) - formula (12), the consistency of the cutting layer area of the inner surface of the turned member is the highest design goal, the cutting layer area allowed by the cutting force of the inner surface of the turned member and the cutting interference of the tool are the constraint conditions, the initial main deflection angle of the tool, the tool tip angle, the tool tip arc radius and the feed per revolution are the process design variables, and the turning process design method for turning the inner surface of the member with different machining inclination angles is proposed, such as Figure 12 .

[0082] Using the method of figure (12), the turning process design scheme for turning the large end inner cylindrical surface, inner conical surface and small end bottom surface of the large conical member is obtained, as shown in table 1, table 2.

[0083] Table 1 Turning tool (55°) turning process design scheme 1 for inner surface of member

[0084]

[0085] Table 2 Turning tool (80°) turning process design scheme 2 for inner surface of member

[0086]

[0087] According to table 1, table 2, using the above two cutting process schemes to process the large end inner cylindrical surface, inner conical surface and small end bottom surface of the member, the cutting layer area with high consistency can be obtained. By comparing the semi-finishing cutting layer area and the finishing cutting layer area, the cutting layer areas of the two process schemes are similar, and they can be used for direct transmission titanium alloy hub turning.

[0088] Compared with scheme 1, the consistency of semi-finishing cutting layer area of scheme 2 is improved by 27%, and the consistency of finishing cutting layer area is improved by 23%, which can be used as the preferred process scheme for direct transmission titanium alloy hub turning.

[0089] The difference between the disclosed technology and the existing technology is:

[0090] The existing turning process design method for turning the inner surface of large titanium alloy member is aimed at a single member machining surface, with the goal of controlling the nominal cutting layer area, cutting force, machining surface morphology and surface form error of the single machining surface, focusing on the influence of speed, feed per revolution and cutting depth, ignoring the influence of machining inclination angle, tool angle and matching relationship between cutting parameters on residual cutting layer area, there is a principle deviation in the calculation and evaluation of cutting layer area, which cannot meet the requirements of cutting layer area consistency and cutting stability for continuous turning of multiple machining surfaces of the member.

[0091] According to the machining inclination angle change formed by the large titanium alloy component large end inner cylindrical surface, inner conical surface and small end bottom surface and the tool, and the influence on the residual cutting layer area of the machining surface, the cutting layer area and its consistency calculation and evaluation model are established for turning multiple component machining surfaces with different machining inclination angles, the highest consistency of the cutting layer area of multiple machining surfaces is taken as the design target, the turning inner surface process design method of the large titanium alloy component is proposed, the turning process design scheme of the large titanium alloy component is obtained, and the consistency of the cutting layer area of the large end inner cylindrical surface, the inner conical surface and the small end bottom surface of the turning component is effectively improved.

[0092] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are only by way of example and that modifications, changes, substitutions and alterations can be made thereto without departing from the spirit and scope of the application as set forth in the following claims and equivalents thereof.

Claims

1. A method of controlling the area of multiple internal surface cut layers of a large titanium alloy component during turning, characterized by, The method comprises the following steps: Step one, calculating the area of the residual cutting layer of the inner surface of the turning: determining the structure of the inner surface of the component, the cutting layer parameters and the feed path, setting the tool cutting processing inclination angle α of the inner cylindrical surface of the component to 0°, the processing inclination angle α of the inner conical surface of the component to 34.6° and the processing inclination angle α of the small end bottom surface of the component to -90°, calculating the angle between the tool main cutting edge, the secondary cutting edge and the tool feed speed, calculating the tool working main deflection angle and the working secondary deflection angle, confirming that the cutting layer area of the cutting inner cylindrical surface, the inner conical surface and the small end bottom surface of the component is affected by the nominal cutting area and the residual cutting layer area; Step two, analyzing the influence characteristics of the processing inclination angle on the cutting layer area: using the same tool, keeping the posture angle of the tool and the titanium alloy component axis unchanged, turning the inner surface of the component with the same cutting parameters, the cutting layer area of the inner cylindrical surface with a processing inclination angle of 0° and the small end bottom surface with a processing inclination angle of -90° is equal, using the matched tool to turn the inner surface of the component with different processing inclination angles, and obtaining the cutting layer area; Step three, analyzing and judging the consistency of the cutting layer area: obtaining the turning tool with a tool nose angle of 80° and 55°, the calculation and judgment method of the consistency of the cutting layer area of the inner surface of the component is: Wherein, δ AD is the consistency evaluation index of the cutting layer area, i and j are the inner surfaces of components i and j, respectively, A Dmi and A Dmj are the nominal cutting layer areas of the inner surfaces i and j, respectively, A Dhi and A Dhj are the residual cutting layer areas of the inner surfaces i and j, respectively, A Di and A Dj are the cutting layer areas of the inner surfaces i and j, respectively, and A Dj is less than A Di . Step four, confirming the consistency of the cutting layer area: setting the highest goal of the consistency of the cutting layer area of the turning inner surface of the component, taking the allowable cutting layer area of the turning inner surface of the component and the cutting interference of the tool as the constraint conditions, taking the initial main deflection angle of the tool, the tool nose angle, the tool nose arc radius and the feed per revolution as the variables, and obtaining the consistent results of the turning inner surface of the large titanium alloy component.

2. The method of claim 1, wherein: In step one, the included angle κ, κ' between the main cutting edge s, the minor cutting edge s' and the tool feed speed v f is respectively: s κ = 270° - (α + κ s ), κ' = 270° - (α + κ s + ε r0 ) s r0 r ;​​ wherein a is the machining inclination angle, k r0 is the initial main relief angle of the tool, e r is the tool nose angle.

3. The method of claim 2, wherein: In step one, the tool working principal flank angle κ r and the working minor flank angle κ r are respectively:

4. The method of claim 3, wherein: In step one, the cutting layer area A of the inner cylindrical surface, the inner conical surface and the small end bottom surface of the cutting member D Affected by the nominal cutting area A Dm And the residual cutting layer area A Dh Influence; A D = A Dm - A Dh , A Dm = f x a p ; wherein f is the feed per revolution of the workpiece, a p is the depth of cut.

5. The method of claim 3, wherein: When the tool nose arc radius is 0, the residual cutting layer area is: -90° < a < 90° - (K r0 + ε r ) and 90° - K r0 < a < 90°.

6. The method of claim 3, wherein: When the tool tip radius is greater than 0 and f > 2r ε sinκ r The residual cutting layer area is: where h max1 is f > 2r ε sin k r is the maximum residual height, r ε is the tool nose radius.

7. The method of claim 3, wherein the method further comprises: When the tool tip circular arc radius is greater than 0, and f≤2r ε sinκ r , the residual cutting layer area is: where h max2 is the maximum residual height for f < 2r ε sin k r .

8. The method of claim 1, wherein: In step two, based on the cutting layer area of ​​the inner surfaces with different machining angles obtained in step one, the inner diameter of the titanium alloy component ranges from 484 mm to 824 mm. The machining angles of the large end, inner conical surface, and small end bottom surface of the inner cylindrical surface of the component are 0°, 34.6°, and -90°, respectively. The initial principal cutting edge angle κ of the tool is... r0 The blade tip angle is 95°, ε r The angle is 80°, the radius of the tool tip arc is 0, and the depth of cut is a. p The thicknesses are 0.2mm, 0.4mm, and 0.6mm respectively.

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