CN102085576B - Five-axis linkage variable-axis plunge milling numerically controlled processing method for blade part of integral impeller - Google Patents

Abstract

A five-axis linkage variable-axis plunge-milling numerical control machining method for an integral impeller blade part, which is carried out according to the following steps: 1) split the space free-form surface of the part to be machined into multiple areas to be machined; 3) Select the appropriate plunge milling cutter; 4) Plan the machining route; 5) Generate the NC tool trajectory; 6) Simulation of the NC program; 7) Edit the NC program; 8) Process parts; The shaft plunge milling method improves the machining efficiency of the rough groove removal of the overall impeller to remove large margins, and solves the processing problem that the residual margin of the blade surface is not uniform after the free-form surface fixed shaft plunge milling, and it is necessary to use a spherical milling cutter for smoothing processing. The present invention can be used for five-axis numerical control milling processing of complex free-form surface structures such as axial-flow integral impellers and integral leaf rings, which need to remove large margin parts, and multi-axis processing of simple free-form surface structures such as centrifugal integral impellers and mold processing. CNC milling.

Description

A five-axis linkage variable-axis plunge-milling numerical control machining method for the blade part of the integral impeller

technical field

The invention belongs to the technical field of mechanical manufacturing, and relates to a processing method of mechanical parts, in particular to a five-axis linkage variable-axis plunge-milling numerical control processing method for an integral impeller blade part.

Background technique

Integral impeller processing technology is one of the key technologies of advanced aero-engines. Due to the limitation of special processing technology on material properties and processing accuracy requirements, machining is still the most widely used processing method; the blade part of the integral impeller is a complex free-form surface , the blade part cannot be forged directly, therefore, the blanks of the integral impeller are mostly integral forgings, which causes the material removal rate of the integral impeller to increase greatly during the processing process, and the maximum removal rate can reach more than 93%. At present, drilling and milling or displacement plunging milling are mostly used for rough slotting of integral impellers. Since drilling and milling or displacement plunging milling are fixed-axis processing methods, and the shape of the free-form surface is relatively complex, the undercut position and undercut amount They are all very large, and the method of point milling with ball end milling cutter or end R milling cutter must be used to remove the undercut. Since this processing method is formed by processing at least twice, the processing time is doubled, the amount of data processing is large, and the processing efficiency is low. ``

Therefore, in the rough grooving process of the integral impeller, which tool and processing method to use can make the machining surface allowance more uniform, provide guarantee for fine milling, improve processing efficiency and reduce processing cost, and become the first choice of integral impeller. The key to rough grooving technology.

Contents of the invention

The object of the present invention is to provide a five-axis linkage variable-axis plunge-milling numerical control machining method for the integral impeller blade part. The numerical control machining method improves the machining efficiency and reduces the production cost. Consistency of residual stress in finish milling. ``

The technical solution idea of the present invention is to further expand the plunge-milling technology of the displacement fixed axis, combine displacement and plunge-milling, and realize the plunge-milling function during the displacement process. ``

According to the present invention, a five-axis linkage variable axis plunge-milling CNC machining method for the blade part of the integral impeller is carried out according to the following steps:

1) Split the space free-form surface of the part to be processed into multiple regions to be processed;

In each area to be processed, ensure that the curvature direction between the cutting start point and the end point in the cutting direction of the tool is basically the same, and the curvature change of the tool in the processing and traversing direction is not more than 10%;

2) Analyze the force situation during tool processing;

Since the plunge milling cutter has a small tolerance to radial force, it is necessary to analyze clearly the stress state of each point of the plunge milling cutter in the five-axis linkage machining process to ensure that the plunge milling cutter is borne during the machining process. The radial force is the smallest, and at the same time, the durability of the fillet R part of the insert milling cutter must also be considered;

3) Select the appropriate plunge milling cutter;

According to the analysis of steps 1) and 2), in order to ensure the processing efficiency, the diameter of the plunge milling tool should not be too small. At the same time, it should be considered to avoid the collision and grinding of the tool holder and the part during the cutting and retracting process. Therefore, there must be a strong gap between the blades. Therefore, standard tools are selected; in addition, according to the characteristics that the cutting edge of the plunge milling cutter does not reach the center, the side of the tool cutting motion direction needs to be pre-grooved to ensure that there is no interference with the non-cutting parts of the tool; 

4) Planning the processing route;

According to the processing characteristics of the plunge milling cutter, the cutting depth in the stepping direction of the tool path should be processed from deep to shallow, and advance along the curved surface in the stepping direction, and the cutting width will change. In order to ensure that the non-cutting parts do not collide with the parts , the cutting step distance should not be greater than 50% of the cutting edge width of the tool;

5) Generate NC tool path;

Using the multi-axis programming function of UG (three-dimensional CAD design software) and MAX-PAC (turbine impeller CNC machining programming software package) software, establish and generate tool paths in the selected cutting area;

6) NC program simulation;

The generated tool trajectory is simulated by the NC machining simulation software, and check whether there is overcut, undercut or tool interference in the simulation; if there is overcut, undercut or tool interference, go to step 7); if there is no overcut, undercut or tool interference cutting, undercutting or tool interference, skip step 7) and directly perform step 8);

7) Edit NC program;

Since the tool path calculated in step 5) may have overcutting, undercutting or tool interference, after the VERICUT (NC machining simulation system) software in the step 6) performs simulation processing, find out the overcutting, undercutting or tool interference statement; if the problem or program statement is more and more complex, it is necessary to readjust and calculate the program. If the problem is less or simpler, it can be fine-tuned manually. Generally, only the values of the three linear axes of X, Y, and Z are adjusted during manual adjustment, and the adjustment amount is usually not more than 1mm. After the adjustment is completed, skip to step 6); 8) Process parts;

The five-axis linkage variable-axis plunge-milling numerical control machining method of the integral impeller blade part of the present invention solves the technical problem of low material removal efficiency per unit time when complex free-space curved surfaces are processed with poor openness, improves processing efficiency, and reduces The production cost is reduced, and the machining surface allowance is guaranteed to be uniform.

Description of drawings

Figure 1 is a schematic diagram of the area to be processed divided by the blade of the integral impeller along the chord width direction

Figure 2a is a schematic diagram of the force state of the tool when processing the blade

Figure 2b is a partial enlarged view of A in Figure 2a

Figure 3 is a schematic diagram of the stepping direction of milling cutter processing

Figure 4 is a schematic diagram of tool machining trajectory

In the figure 1. Blade 2. Area to be processed 3. Chord width direction 4. Tool 5. Stepping direction 6. Tool path.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

The specific dimensions, materials and processing parameters of the integral impeller of the present embodiment are as follows:

The maximum outer diameter of the blade: 936mm;

The minimum outer diameter of the blade: 482mm;

The maximum chord width of the blade: 210mm;

Number of blades: 20;

Maximum thickness of blade tip: 4.5mm;

Maximum thickness of leaf root: 12.5mm;

Material: titanium alloy;

Processing parameters: processing line speed 30 ~ 40m / min;

The five-axis linkage variable axis plunge-milling CNC machining method of the integral impeller blade part of the present invention is carried out according to the following steps:

1) In Figure 1, the entire blade 1 of the integral impeller is divided into several areas 2 to be processed along the chord width direction 3;

2) According to the method in Figure 2a and Figure 2b, analyze in detail the force state of the typical tool 4 track in different parts;

3) Select a suitable tool 4 according to the analysis results of steps 1) and 2). In this case, a plunging milling tool 4 with a diameter of Φ32mm is selected, the blade width is 10mm, and the blade fillet is R1.2mm;

4) In Figure 3, pre-groove the side of the cutting tool 4 in the cutting motion direction, and then determine the processing step direction 5;

5) Using the multi-axis programming function of UG (three-dimensional CAD design software) and MAX-PAC (turbine impeller CNC machining programming software package) software, establish and generate tool path 6 in the selected cutting area, as shown in Figure 4 , since this case is processing an axial-flow integral impeller, the SI (integral closed impeller) CAM function module of the impeller-specific MAX-PAC software is used, and its advantage is that the processing area of the integral impeller blade 1 free-form surface can be parameterized ;In this case, the blade 1 part of the integral impeller to be processed is greatly distorted. By calculation, when the cutting depth is not greater than 11mm, the curvature change is less than 10%. The Z linear axis changes greatly, which meets the force requirements of the plunge milling cutter; the maximum chord width of the blade 1 is 21Omm, calculated according to the maximum cutting depth, and is divided into 20 layers; in order to ensure that the plunge milling cutter does not participate in radial cutting, the cutting depth of the cutter 4 After reaching the position, quickly return along the original road, retract the tool and cross the safety distance of 1 mm to traverse to the next tool track at position 6 and continue cutting;

6) The generated tool path 6 is simulated by VERICUT (NC machining simulation software), and check whether there is overcut, undercut or tool interference in the simulation; if there is overcut, undercut or tool interference, execute Step 7); if there is no overcut, undercut or tool interference, skip step 7), and directly perform step 8);

The generated NC program is as follows: % _ N _ AS90171

N0l0 G90 G94 G00 Z800.0 M3 S350

N0020 G01 X-324.76 Y590.68 Z702.25 A-34.969 B125.043 F20000 .

N0O21 Y41.92 Z318.45

N0022 Y3.41 Z291.51 F3000 .

N0023 Y.13 Z289.22 F100. M07 M08

NO024 X-324.77 Y-.92 Z285.27 A-34.909 B124.544

N0025 X-324.86 Y-2.49 Z281.97 A34.867 B123.918

N0026 X-325. Y-4.35 Z279.1 A-34.836 B123.222

N0027 X-324.86 Y-2.49 Z281.97 A-34.867 B123.918 F3000.

N0028 X-324.77 Y-92 Z285.27 A-34.909 B124.544

N0029 X-324.76 Y.13 Z289.22 A-34.969 B125.043

N0030 X-320.5 Y-1.62 Z292.44 A-35.305 B125.018 F500.

N0031 X-320.45 Y-2.13 Z287.69 A-35.223 B124.645 F100.

N0032 X-320.49 Y-3.32 Z283.82 A-35.164 B124.104

N0033 X-320.6 Y-4.94 Z280.55 A-35.121 B123.464

N0034 X-320.49 Y-3.32 Z283.82 A-35.164 B124.104 F3000.

...

N0197 X-222.18 Y-28.Z337.65 A-41.026 B126.27 NO198 Z800.0 F20000. N0199 M05 M09 N0200 M30

7) Edit NC program

Since the tool path calculated in step 5) may have overcutting, undercutting or tool interference, after the VERICUT (NC machining simulation software) software in step 6) performs simulation processing, find out the overcutting , undercutting or tool interference statements, if there are many and complex problems or program statements, you need to readjust and calculate the program. When the problems are few or relatively simple, you can fine-tune them manually. It has a great influence on the adjustment amount. Generally, only the values of the three linear axes X, Y, and Z are adjusted during manual adjustment. Usually, the adjustment amount is not greater than 1mm. After the adjustment is completed, skip to step 6); During the process, the knife retraction track traverses to the blade root transition point R first, and then retracts along the blade surface, which causes severe overcut during the retraction process, and the maximum overcut reaches more than 1.5mm. At this time, the cutter can be used When moving to the middle of the two blades, change the program to retract the tool along the direction of the tool vector to avoid overcutting of the part;

8) Processing parts

Select the five-axis CNC machining center, clamp the parts according to the given process and technical documents, follow the modeling and machining practices of the axial-flow integral impeller, set the origin of the X-axis and Z-axis machining coordinates at the zero-rotation center, and the Y-axis machining coordinates The origin is set on the stacking axis of the blades, and the processing is carried out according to the process documents and the operation instructions of the machining center.

The present invention adopts the five-axis linkage variable-axis plunge-milling method, and by selecting appropriate plunge-milling cutters and processing parameters, the processing efficiency and pass rate of the overall impeller coarse groove removal and large margin are improved, and the processing cost and the five-axis machining center are reduced. It takes a long time to solve the processing problem that the residual margin of the blade surface is not uniform after the free-form surface fixed axis is inserted and milled, and it is necessary to use a spherical milling cutter for finishing treatment. the

The present invention is mainly applied to complex free-form surface structures such as axial-flow integral impellers and integral leaf rings, which need to remove large margin parts for five-axis CNC milling, and can also be applied to simple free-form surface structures such as centrifugal integral impellers and mold processing. Multi-axis CNC milling of parts.

Claims (1)

1. an integral wheel blade-section five-axle linkage change axle is inserted and is milled numerical-control processing method, it is characterized in that: carry out according to the following steps:

1) the space free curved surface is split into a plurality of zones to be processed (2)

In each zone to be processed (2), guarantee on cutter (4) cutting direction between cutting starting point and the terminating point curvature direction consistent, cutter (4) is in processing and cross that the curvature variation is not more than 10 % on the direction;

2) stressing conditions in analysis cutter (4) process

Because cutter is less to the tolerance degree of radial load; Therefore; Must the stress analysis of the every bit of cutter in the five-axle linkage process is clear, with the radial load minimum that guarantees that cutter was born in the process, also to consider the durability at cutter fillet R position simultaneously;

3) select suitable cutter

According to step 1), 2) to analyze, cutter choice criteria cutter is specially the slotting milling cutter of Φ 32mm diameter, blade width 10mm, blade fillet R1.2mm; In addition, according to the Tool in Cutting sword characteristics at center only, the side of cutter (4) cutting movement direction needs fluting in advance, does not have interference to guarantee the non-cutting of cutter (4) position;

4) planning processing route

Processing characteristic according to cutter; Cutter path (6) step direction cutting depth should mode from deep to shallow be processed; Curved surface advances in the step direction upper edge; Cutting width can change, and does not bump with part in order to guarantee non-cutting position, and the cutting step pitch should be not more than 50 % of Tool in Cutting tread degree;

5) generate NC cutting tool track (6)

Utilize the multiaxis programing function of UG three-dimensional CAD design software and MAX-PAC turbo wheel digital control processing programming software bag, in selected cutting zone, set up and generate cutter path (6);

6) numerical control program emulation

Whether the cutter path (6) that generates is carried out the emulation of cutter path (6) through the VERICUT numerical control machining simulation system, and check in emulation, to exist and cut, owe to cut or cutter interference; Cut, owe to cut or cutter interference if having, execution in step 7); Do not cut, owe to cut or cutter interference if having, skips steps 7), direct execution in step 8);

7) editor's numerical control program

Find out and occurred cutting, owe to cut or the statement of cutter interference; If problem or program statement are more, complicated; Then readjust, calculation procedure, if problem is less or when simple, method is finely tuned by hand; Because adjustment A, B axle is big to the influence of adjustment amount; Only adjust the numerical value of X, Y, three linear axes of Z during manual setting, adjustment amount is not more than 1mm, and adjustment is jumped to step 6) after accomplishing;

8) processing parts.

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