An integrated forming machining method for blisk machining

Abstract

The present application relates to the manufacturing technical field of aero-engine blisk, in particular to an integrated forming machining method for blisk machining, which combines abrasive water jet rough machining, electrolytic machining and self-adaptive polishing machining to form an integrated machining method. First, the characteristics of the theoretical model of the blisk part are analyzed, simplified and reconstructed to build a water jet machining process model of the blisk. Then, the abrasive water jet equipment is applied to remove the material of the rough machining of the blade body. After that, the double-sided feeding electrolytic finishing method is determined to machine the blade body and the flow channel of the blisk. Then, the blade body and the flow channel are machined by a sand belt robot. Finally, the precision machining of the blisk is completed. The present application combines the advantages of abrasive water jet rough machining, electrolytic machining and self-adaptive polishing machining, re-plans the machining method and technical path of the blisk, effectively reduces the machining difficulty of the part, finally guarantees the dimensional accuracy and position accuracy of the part, and realizes the high-performance manufacturing and machining of the blisk.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing integral blade disks of aircraft engines, and in particular to an integrated molding processing method for processing integral blade disks. Background Art

[0002] With the high thrust-to-weight ratio performance requirements of aircraft engines, the integral blade disk structure eliminates the escape loss in the gap at the root of the tenon teeth of the mortise and tenon joint blade disk, avoids the micro-wear and cracks caused by improper assembly of the blades and the wheel disc, and the failure caused by damage to the lock piece. At the same time, the number of parts is greatly reduced, which is conducive to assembly and balance. Therefore, it combines the advantages of good rigidity, high balance accuracy, and long rotor service life. However, the integral blade disk widely uses high-performance metal materials such as titanium alloy and high-temperature alloy, and the material machinability is poor. Due to the structural characteristics of the blade disk such as thin spokes, large area, complex blade shape, nonlinear and narrow flow channel, the manufacturing technology requirements are extremely high, which also makes the comprehensive manufacturing process technology of the integral blade disk a global problem.

[0003] At present, the main forming method of integral blades is CNC milling. However, the use of CNC milling places high demands on processing strategy planning and processing equipment performance. At the same time, the processing quality is difficult to guarantee, the processing efficiency is low, the tool life is short, and the manual polishing workers have high workload and poor surface consistency of parts. Repeated polishing and repair are required, which takes up a lot of inspection resources and time. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides an integrated forming method for processing an integral blade disk; the specific technical solution is as follows:

[0005] An integrated forming method for machining an integral blade disk, comprising combining abrasive water jet rough machining, electrolytic machining, and adaptive polishing to form an integrated machining method, the method comprising the following steps:

[0006] Step 1: Analyze the theoretical model characteristics of the blisk parts and complete the construction of the blisk water jet machining process model;

[0007] Considering the inflexibility of the jet in abrasive water jet machining, while ensuring the requirements of three-dimensional complex surface geometry, machining accuracy and machining consistency, the characteristics of the parts are analyzed, simplified and reconstructed, and based on the principle of forming a variable tangent cutting path with maximum non-interference inclusion, a process model for abrasive water jet machining is formed;

[0008] The abrasive water jet processing is a process in which softened water is pressurized and ejected through a nozzle, which has a large kinetic energy waterline to cut the workpiece. After the high-pressure water is mixed with the abrasive, the abrasive has a main impact and cutting effect on the workpiece, and the abrasive particles produce high-frequency erosion on the workpiece, thereby improving the processing capacity and work efficiency of the high-pressure water jet.

[0009] Step two, according to the abrasive water jet machining process model, set the process parameters of abrasive water jet machining, complete the abrasive water jet program preparation;

[0010] The abrasive water jet process parameters are specifically: machining pressure 350~400Mpa, abrasive supply not less than 0.5kg / min, cutting feed not more than 30mm / min;

[0011] Step three, import the trajectory program into the control system of abrasive water jet machining equipment, according to the planned process route, carry out the rough machining of the blade, and control the single side allowance in 0.2-0.5mm after machining;

[0012] Install the part on the tool fixture, align, complete the abrasive water jet machining of the inlet end in the abrasive water jet machining equipment based on the process model, then turn over the part and carry out the abrasive water jet machining of the exhaust end;

[0013] Step four, according to the characteristics of the part, determine the feed electrolytic finishing method, process the whole blade, prepare special cathode electrode, and set the process parameters of electrolytic machining;

[0014] The electrolytic machining is a method of removing material based on the positive dissolution mechanism of electrochemical reaction, which has the characteristics of no loss and no cutting force in the machining process, and is suitable for difficult machining. The electrolytic machining of the whole blade can process the blade basin and the blade back respectively, or process the blade basin and the blade back simultaneously.

[0015] Step five, turn on the power and electrolyte, start the electrolytic semi-finishing of the blade and the flow channel;

[0016] When electrolytic machining, the blade back electrode and the blade basin electrode approach each other to form a machining cavity, and the electrolyte enters the machining cavity to realize precise electrolytic machining of the blade;

[0017] Step six, after the electrolytic semi-finishing is completed, the blade surface allowance is 0.04mm-0.1mm, and the normal allowance of the leading and trailing edges is 0.06mm-0.1mm;

[0018] Step seven, according to the three-coordinate measurement results of the blade surface and the leading and trailing edges after electrolytic machining, analyze the allowance, plan the polishing path and polishing parameters, and finally ensure that the size accuracy and surface quality of the whole blade, the leading and trailing edges, the flow channel and other areas meet the technical requirements.

[0019] The self-adaptive abrasive belt polishing machining is an abrasive belt polishing method which automatically plans the machining area and machining path according to the allowance distribution of the whole blade after finishing.

[0020] The margin analysis is to determine the margin distribution of the entire blade surface after completing the alignment of the actual measurement model and the theoretical model, with the principle of ensuring that the theoretical model is within the tolerance range and the margin is maximized and uniform.

[0021] The preferred embodiment of the integrated forming processing method for processing an integral blade disk is that, in step seven, the polishing path planning is divided into two methods: the first method is to plan the polishing area and polishing path based on the residual analysis results; the second method is to create several sections based on the blade body, and the polishing path is a spiral motion around the section line, and the dynamic change of the polishing parameters at each point on the polishing path controls the material removal amount.

[0022] The preferred embodiment of the integrated blisk processing method is that the first method of polishing route planning is to first rough-polish the area with the highest blade surface margin, then rough-polish the area with the second highest blade surface margin, rough-polish the leading and trailing edges, and finally fine-polish the entire blade to ensure a smooth transition between the blade surface and the leading and trailing edges. The rough-polishing belt wheel feeds in the direction of the longitudinal blade stacking axis, while the fine-polishing feed motion is a spiral motion along the transverse cross-section of the blade.

[0023] The integrated molding processing method for processing an integral blade disk, the preferred embodiment of which is that in step seven, the belt polishing parameters are set as follows: the linear speed for grinding the blade profile is 8m / s-12m / s, and the linear speed for grinding the intake and exhaust edges is 12m / s-15m / s; the abrasive material of the belt is SiC or aluminum oxide, abrasive belts with grains of #180, #240, and #320 are selected for rough polishing, and abrasive belts with grains of #1500 and #2000 are selected for fine polishing, and the belt tension is controlled at 5N-10N.

[0024] The preferred embodiment of the integrated forming processing method for processing an integral blade disk is that, in step 4, the electrolytic processing parameters are set as follows: processing voltage 5V-25V, conductivity 60 ms / cm-140ms / cm, electrolyte pressure 5bar-16bar, electrolyte temperature 20°C-35°C, vibration frequency 25Hz-45Hz, vibration amplitude 0.25mm-0.45mm, vibration power supply angle 60°-120°, and feed speed 0.1mm / min-1.0mm / min.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] Based on the characteristics and requirements of each stage of rough machining, semi-finishing and finishing of the integral blade disk, the present invention combines the advantages of abrasive water jet rough machining, electrolytic machining and adaptive polishing, re-plans the integral blade disk machining method and technical path, optimizes the integral blade disk machining method and technical path, determines the machining methods with different adaptability, and can effectively weaken the machining difficulty of parts at each stage, effectively reducing the machining difficulty of parts.

[0027] The technical solution of the present invention effectively reduces the difficulty of processing parts and reduces the existing milling processing cycle from 200 hours to less than 100 hours. It can ultimately ensure the dimensional accuracy and positional accuracy of the parts, thereby improving processing efficiency and processing quality, and realizing high-performance manufacturing processing of blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the overall blade disk structure;

[0029] Figure 2 Schematic diagram of the cross section of the abrasive water jet machining of the integral blade;

[0030] Figure 3 Schematic diagram of the electrolytic finishing method for the blisk;

[0031] Figure 4 This is a flow chart of the adaptive belt polishing technology solution;

[0032] Figure 5 This is the measured contour of the leading edge of the blade after processing;

[0033] Figure 6 This is the measured contour of the trailing edge of the blade disk after processing;

[0034] Figure 7 This is the measured contour diagram of the blade surface of the blade disk after processing.

[0035] In the figure, 1-blade body, 2-flow channel, 3-leading edge, 4-trailing edge. Implementation Method

[0036] The present invention will be described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited by the accompanying drawings.

[0037] like Figure 1-7 As shown, an integrated forming processing method for processing an integral blade disk includes combining abrasive water jet roughing, electrolytic machining and adaptive polishing to form an integrated processing method; the steps of the method are as follows:

[0038] Step 1: Analyze the theoretical model characteristics of the blisk part and use a multi-trajectory approach to approach the blade contour line to construct a water jet machining process model for the blisk.

[0039] Step two, according to the abrasive water jet machining process model, the abrasive water jet program is compiled, and the abrasive water jet process parameters are set as follows: machining pressure 360 MPa, abrasive supply 0.6 kg / min, cutting feed 30 mm / min;

[0040] Step three, the trajectory program is imported into the control system of the abrasive water jet machining equipment, the part is installed on the tool fixture, the intake end abrasive water jet machining is completed according to the machining trajectory of the intake end, then the part is manually turned over, the exhaust end abrasive water jet machining is carried out according to the machining trajectory of the exhaust end, and the full surface water jet machining is completed, and the single side allowance is controlled at 0.2 mm-0.5 mm after machining;

[0041] Step four, according to the characteristics of the part, the double-sided feed electrolytic finishing method is used to process the blade of the integral blade disc, and the electrolytic machining process parameters are set as follows: machining voltage 10 V-20 V, conductivity 70 ms / cm-120 ms / cm, electrolyte pressure 10 bar, electrolyte temperature 25 DEG C, vibration frequency 25 Hz-45 Hz, vibration amplitude 0.25 mm-0.45 mm, vibration feeding angle 75 DEG, feeding speed 0.6 mm / min;

[0042] Step five, turn on the power and electrolyte, the blade back electrode and the blade basin electrode approach each other to form a machining cavity, the electrolyte enters the machining cavity, and the electrolytic semi-finishing of the blade 1 and the flow channel 2 is started;

[0043] Step six, after the electrolytic semi-finishing is completed, the blade surface allowance is 0.04 mm-0.1 mm, and the normal allowance of the leading edge 3 and the trailing edge 4 is about 0.06 mm-0.1 mm;

[0044] Step seven, the three-coordinate measuring machine is used to complete the measurement of 5-8 integral blade disc blades, the allowance analysis tool is used for allowance analysis, and the sand belt polishing area and sequence are determined as follows: firstly, the blade surface allowance highest area is coarsely polished, then the blade surface allowance secondary high area is coarsely polished, the leading edge 3 and the trailing edge 4 are coarsely polished, and finally the whole blade 1 is finely polished, wherein the coarse polishing sand belt wheel feeding direction is the longitudinal blade stacking axis direction, and the fine polishing feeding motion is the spiral motion along the blade 1 transverse section.

[0045] The robot polishing parameters are set as follows: the linear velocity of the sand belt in grinding the blade surface is 8 m / s-12 m / s, the linear velocity when polishing the inlet and outlet edges is 12 m / s-15 m / s, the sand belt abrasive material is SiC, the coarse polishing abrasive belt is #240, the fine polishing abrasive belt is #2000, and the sand belt tension is controlled at 7 N.

[0046] It is verified that the blade profile is basically in the part, as shown in Figure 5 The surface roughness is measured by using a roughness meter, and the numerical value is Ra0.4, and the profile and surface roughness completely meet the technical requirements.

Claims

1. An integrated forming method for processing an integral blade disk, characterized by: Combining abrasive water jet roughing, electrolytic machining and adaptive polishing, an integrated machining method is formed, which includes the following steps: Step 1: Analyze the theoretical model characteristics of the blisk parts and complete the construction of the blisk water jet machining process model; Considering the inflexibility of the jet in abrasive water jet machining, while ensuring the requirements of three-dimensional complex surface geometry, machining accuracy and machining consistency, the characteristics of the parts are analyzed, simplified and reconstructed, and based on the principle of forming a variable tangent cutting path with maximum non-interference inclusion, a process model for abrasive water jet machining is formed; Step 2: According to the abrasive water jet processing process model, the process parameters of the abrasive water jet processing are set to complete the abrasive water jet processing program; The abrasive water jet machining process parameters are as follows: machining pressure 350-400 MPa, abrasive supply not less than 0.5 kg / min, and cutting feed not more than 30 mm / min; Step 3: Import the trajectory program into the control system of the abrasive water jet machining equipment, and perform rough machining of the blade body to remove the allowance according to the planned process route. After machining, the single-side allowance is controlled at 0.2-0.5mm. The part is mounted on the fixture, aligned, and the abrasive water jet machining of the air intake end is completed based on the process model on the abrasive water jet machining equipment. The part is then flipped over and the abrasive water jet machining of the exhaust end is performed. Step 4: Determine the feed electrolytic finishing method based on the part characteristics, process the integral blade disc blade body, prepare a dedicated cathode electrode, and set the electrolytic machining process parameters; Step 5: Turn on the power supply and electrolyte to start electrolytic semi-finishing of the blade body and flow channel; During electrochemical machining, the blade back electrode and the blade basin electrode move closer to each other to form a machining cavity, and the electrolyte enters the machining cavity to achieve precise electrochemical machining of the blade; Step 6: After the electrolytic semi-finishing is completed, the blade surface allowance is 0.04mm-0.1mm, and the normal allowance of the leading and trailing edges is 0.06mm-0.1mm; Step seven: Based on the three-dimensional measurement results of the blade body surface and leading and trailing edges after electrochemical machining, perform a margin analysis and plan the polishing path and polishing parameters to ultimately ensure that the dimensional accuracy and surface quality of the blade body, leading and trailing edges, and flow channel areas of the entire blade disk meet the technical requirements.

2. The integrated forming method for blisk processing according to claim 1, characterized in that: In step seven, the polishing path planning is divided into two methods: the first method is to plan the polishing area and polishing path based on the residual analysis results; the second method is to create several sections based on the blade body, and the polishing path is a spiral motion around the section line. The dynamic change of the polishing parameters at each point on the polishing path controls the material removal amount.

3. The integrated forming method for blisk processing according to claim 2, characterized in that: The first method of polishing route planning is to first rough-polish the area with the highest blade surface allowance, then rough-polish the area with the second highest blade surface allowance, rough-polish the leading and trailing edges, and finally fine-polish the entire blade to ensure a smooth transition between the blade surface and the leading and trailing edges; the feed direction of the rough-polishing belt wheel is the longitudinal blade stacking axis direction, and the fine-polishing feed motion is a spiral motion along the transverse cross-section of the blade.

4. The integrated forming method for blisk processing according to claim 1, characterized in that: In step seven, the polishing parameters are set as follows: the linear speed for grinding the blade profile is 8m / s-12m / s, and the linear speed for grinding the intake and exhaust edges is 12m / s-15m / s; the abrasive material of the sanding belt is SiC and aluminum oxide, #180, #240, and #320 abrasive belts are selected for rough polishing, and #1500 and #2000 abrasive belts are selected for fine polishing, and the belt tension is controlled at 5N-10N.

5. The integrated forming method for blisk processing according to claim 1, characterized in that: In step 4, the electrochemical machining process parameters are set as follows: machining voltage 5V-25V, conductivity 60 ms / cm-140ms / cm, electrolyte pressure 5bar-16bar, electrolyte temperature 20℃-35℃, vibration frequency 25Hz-45Hz, vibration amplitude 0.25mm-0.45mm, vibration power supply angle 60°-120°, and feed speed 0.1mm / min-1.0mm / min.

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