Technological method for grinding and polishing full molded surface of blade by manipulator

Abstract

The invention relates to a technological method for grinding and polishing a full profile of a blade through a mechanical arm. The technological method comprises the following steps that 1, blade grinding and polishing area division is planned according to a blade structure; 2, a grinding and polishing strategy is planned; 3, a grinding and polishing strategy is planned; 4, selecting a grinding and polishing tool and parameters; step 4.1, selecting a grinding and polishing wheel; 4.2, an abrasive belt is arranged, and the abrasive belt makes contact with a wheel; 4.3, the granularity of a grinding and polishing tool is selected; 4.4, grinding and polishing parameters are selected; 5, a grinding and polishing program is compiled; 6, grinding and polishing pressure is set; 7, checking the point position of the manipulator; 8, grinding and polishing trial machining; the full-profile grinding and polishing machining of the blade is completed in an automatic unit, and the stability of the grinding and polishing quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of automated processing of aero-engine blades, and in particular to a process method for grinding and polishing the entire surface of a blade by a robot. Background Art

[0002] The compressor blades of aircraft engines are usually designed as thin-walled, weakly rigid structures. After CNC milling, the blade surface is mostly polished manually to complete the roughness and contour accuracy of the surface. Affected by the workers' skill level and polishing conditions, the polishing quality stability is poor, and there are problems such as "over-polishing" or "under-polishing" or the roughness does not meet the drawing requirements of Ra≤0.4μm. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a process method for grinding and polishing the entire surface of a blade by a robot; the specific technical scheme is as follows:

[0004] A process for grinding and polishing the entire surface of a blade by a robot, comprising the following steps:

[0005] Step 1: Plan the blade grinding and polishing area division according to the blade structure

[0006] According to the structural design characteristics of the blade, the entire blade is planned into flow channel surface, transition R, leading edge profile, trailing edge profile, basin side profile, back side profile, corners, milling cutter corner marks, and cutting marks;

[0007] Step 2: Grinding and polishing strategy planning

[0008] A grinding and polishing wheel is used for grinding and polishing, and the grinding and polishing strategy is: basin side corner a→basin side corner b→basin side corner c→basin side corner d→milling cutter corner trace→basin side small end blade root profile→basin side large end blade root profile→basin side small end blade root profile→basin side transition R3→basin side flow channel surface a→basin side transition R3.5→basin side flow channel surface b→back side corner a→back side corner b→back side corner c→back side corner d→milling cutter corner trace→back side small end blade root profile→back side large end blade root profile→back side small end blade root profile→back side transition R3→back side flow channel surface a→back side transition R3.5→back side flow channel surface b;

[0009] Step 3: Grinding and polishing strategy planning

[0010] Abrasive belts are used for grinding and polishing, and the grinding and polishing strategy is: basin side connecting knife mark a→basin side connecting knife mark b→back side connecting knife mark a→back side connecting knife mark b→front edge R→trailing edge R→basin side profile→back side profile;

[0011] Step 4: Grinding and polishing tool and parameter selection

[0012] Select grinding and polishing wheels, abrasive belts, abrasive belt contact wheels and grinding and polishing parameters in sequence

[0013] Step 4.1: Selection of grinding and polishing wheel

[0014] The size of the R of the grinding and polishing wheel needs to be based on the size of the transition R of the grinding and polishing part. The R of the grinding and polishing wheel should be smaller than the transition R of the grinding and polishing part, and the difference between the two is between 0.5 and 1.0 mm. Another parameter of the grinding and polishing wheel is the size of its diameter D1. By drawing a diagram to avoid interference, it is calculated that the radius of curvature of the grinding and polishing wheel should be smaller than the radius of curvature of the grinding and polishing part, that is, D1 < D2. On the premise of meeting this requirement, select a grinding and polishing wheel with a larger diameter, and its diameter is selected as D1 = 30 - 60 mm;

[0015] Step 4.2: Abrasive belt and abrasive belt contact wheel

[0016] The selection of the abrasive belt mainly considers two factors. First, the selected abrasive belt should meet the requirements in terms of material, that is, the material of the abrasive belt should not contain elements harmful to the parts to be polished. When grinding and polishing titanium alloy materials, abrasive belts containing elements such as chlorine, copper, brazing, and cadmium cannot be selected. For polishing titanium alloy and superalloy, nylon abrasive belts, ceramic abrasive belts, and zirconia alumina abrasive belts should be selected;

[0017] During grinding and polishing, the abrasive belt contact wheel is used to support the contact between the abrasive belt and the part. Its parameters are mainly thickness L, diameter D3, and drum-shaped radius of curvature R. The thickness L of the abrasive belt contact wheel is the same as the width of the abrasive belt, and is selected according to the size of the part. The thickness of the contact wheel for blade grinding and polishing is selected as L = 5 mm or L = 10 mm; The selection method of the diameter D3 is the same as that of the radius of curvature of the grinding and polishing wheel in Step 4.1, D3 = 25 mm - 30 mm; The size of the drum-shaped radius of curvature R is given according to the radius of curvature of the polished part, R = 20 mm - 25 mm;

[0018] Step 4.3: Selection of the particle size of the grinding and polishing tool

[0019] The particle size of the grinding and polishing wheel is selected according to the amount of removal. When the amount of removal is between 0.03 mm and 0.05 mm, the selected particle size is 400# - 600#, and when the amount of removal is between 0.01 mm and 0.03 mm, the selected particle size is 800# - 1200#;

[0020] The particle size of the abrasive belt also needs to be selected according to the amount of removal. When the amount of removal is between 0.03 mm and 0.05 mm, the selected particle size is 200# - 300#, and when the amount of removal is between 0.01 mm and 0.03 mm, the selected particle size is 400# - 600#;

[0021] Step 4.4: Selection of grinding and polishing parameters

[0022] The grinding and polishing parameters are mainly linear velocity Vc and feed rate F, which are determined according to the material and removal amount of the parts being ground and polished. Under the conditions of the removal amount set in step 4.3, the linear velocity Vc of the abrasive belt is 300mm / min~350m / min, and the feed rate F is 250mm / min~300mm / min; the linear velocity Vc of the grinding and polishing wheel is 200mm / min~250m / min, and the feed rate F is 200mm / min~250mm / min;

[0023] Step 5: Program the grinding and polishing program

[0024] The grinding and polishing program is programmed with general programming software. The abrasive belt grinding and polishing and the grinding and polishing wheel grinding and polishing are programmed according to the milling processing method. The post-processing of the program adopts the post-processing environment of the robot grinding and polishing equipment to process the program into a format that the robot grinding and polishing equipment can receive.

[0025] Step 6: Grinding and polishing pressure setting

[0026] The selection of grinding and polishing pressure needs to be combined with the removal amount, feed speed and linear speed. Under the setting conditions in step 4.3, the contact pressure between the abrasive belt and the blade is 0.6 bar to 1.0 bar, and the contact pressure between the grinding and polishing wheel and the blade is 4 bar to 5 bar.

[0027] Step 7: Robot position calibration

[0028] When the grinding wheel is stationary, call up the grinding and polishing routine; in the manual low-speed state, observe the corresponding relationship between the posture of the manipulator and the position of the grinding wheel; the moving speed ratio of the manipulator is selected as 10%, which is conducive to accurately observing the position changes and preventing collisions; if the position is abnormal, the enable button of the teach pendant should be released immediately;

[0029] Step 8: Grinding and polishing

[0030] During the trial grinding and polishing, a single-step method is adopted. It is necessary to observe whether there is any collision problem at all times. At the same time, it is also necessary to listen to the sound to observe whether there is any vibration. After grinding and polishing, the surface condition and integrity analysis should be carried out to check whether the contour size and surface roughness meet the requirements.

[0031] The preferred embodiment of the process method for grinding and polishing the entire surface of a blade by a robot is as follows: in step 1, the boundary between the flow channel surface and the transition R is 1mm to 2mm beyond the transition R;

[0032] The boundary between the leading edge profile and the trailing edge profile is 2mm to 3mm from the tangent point of the leading and trailing edges R;

[0033] The remaining part of the profile is divided into the basin side profile and the dorsal side profile;

[0034] The corners are the four corners of the blade profile, which need to be polished separately;

[0035] The cutting marks are the program indirect cutters in the blade profile finishing process, and there are two cutting marks on the profile surface.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] The technical solution of the present invention can realize the full-surface grinding and polishing of blades in an automated unit, and the contour accuracy and qualified rate of grinding and polishing are greatly improved; the stability of grinding and polishing quality is guaranteed. Through the above method, the qualified rate of blade grinding and polishing is improved, the waste loss is reduced, and good results are achieved. It can be promoted and applied in the automated processing of other types of engine stator blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the full-shaped basin-shaped structure of the blade;

[0039] Figure 2 This is a schematic diagram of the back structure of the full blade surface;

[0040] Figure 3 for Figure 2 BB structural diagram;

[0041] Figure 4 This is a schematic diagram of the grinding and polishing wheel diameter design;

[0042] Figure 5 Schematic diagram of the structure of the abrasive belt and contact wheel.

[0043] In the figure: 1-leading edge profile, 2-trailing edge profile, 3-basin side corner a, 4-basin side corner b, 5-basin side corner c, 6-basin side corner d, 7-milling cutter corner trace, 8-basin side large end blade root profile, 9-basin side small end blade root profile, 10-basin side R3 transition, 11-basin side flow channel surface a, 12-basin side R3.5 transition, 13-basin side flow channel surface b, 14-back side corner a, 15-back side corner b, 16-back side corner c, 17-back side Corner d, 18-dorsal large end blade root profile, 19-dorsal small end blade root profile, 20-dorsal R3 transition, 21-dorsal flow channel surface a, 22-dorsal R3.5 transition, 23-dorsal flow channel surface b; 24-basin side connection mark a, 25-basin side connection mark b, 26-dorsal connection mark a, 27-dorsal connection mark b, 28-leading edge R, 29-trailing edge R, 30-basin side profile, 31-dorsal profile, 32-abrasive belt, 33-contact wheel. DETAILED DESCRIPTION

[0044] The following is combined with Figure 1-5 The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings.

[0045] A process for grinding and polishing the entire surface of a blade by a robot, comprising the following steps:

[0046] Step 1: Plan the blade grinding and polishing area division according to the blade structure

[0047] According to the structural design characteristics of the blade, the entire blade is planned to be divided into flow channel surface, transition R, leading edge profile 1, trailing edge profile 2, basin side profile, back side profile, corners, milling cutter corner marks, and cutting marks;

[0048] Step 2: Grinding and polishing strategy planning

[0049] A grinding and polishing wheel is used for grinding and polishing, and its grinding and polishing strategy is: basin side corner a3→basin side corner b4→basin side corner c5→basin side corner d6→milling cutter corner mark 7→basin side small end blade root profile 9→basin side large end blade root profile 8→basin side small end blade root profile 9→basin side R3 transition 10→basin side flow channel surface a11→basin side R3.5 transition 12→basin side flow channel surface b13→back side corner a14→back side corner b15→back side corner c16→back side corner d17→milling cutter corner mark 7→back side small end blade root profile 19→back side large end blade root profile 18→back side small end blade root profile 19→back side R3 transition 20→back side flow channel surface a21→back side R3.5 transition 22→back side flow channel surface b23;

[0050] Step 3: Grinding and polishing strategy planning

[0051] Abrasive belts are used for grinding and polishing, and the grinding and polishing strategy is: basin side connecting knife mark a24 → basin side connecting knife mark b25 → back side connecting knife mark a26 → back side connecting knife mark b27 → leading edge R28 → trailing edge R29 → basin side profile 30 → back side profile 31;

[0052] Step 4: Grinding and polishing tool and parameter selection

[0053] Select grinding and polishing wheels, abrasive belts, abrasive belt contact wheels and grinding and polishing parameters in sequence

[0054] Step 4.1: Grinding and polishing wheel selection

[0055] The grinding and polishing parts are transferred to R3 and R3.5 respectively, and the grinding and polishing wheel R=2.5 is selected. After drawing and comparing, the grinding and polishing wheel diameter D1=53mm, which can avoid the occurrence of interference.

[0056] Step 4.2: Abrasive belt, abrasive belt contact wheel

[0057] For belt polishing of titanium alloy, choose a 10mm wide zirconium corundum belt.

[0058] The thickness L of the contact wheel is the same as the width of the abrasive belt, and L=10mm is selected. After drawing and comparing the diameter D3, D3=30mm is selected to avoid interference. The size of the drum curvature radius R is also compared by drawing and comparing, and R=20mm~25mm is selected to avoid interference.

[0059] Step 4.3: Grinding and polishing tool grit selection

[0060] After the profile and flow path surfaces are milled, the amount of grinding and polishing removed from the blade is between 0.01mm and 0.03mm, and the grinding and polishing wheel should be of 1200# grit.

[0061] The particle size of the sanding belt should be between 0.01mm and 0.03mm according to the removal amount, so choose 600#.

[0062] Step 4.4: Grinding and polishing parameter selection

[0063] According to the removal amount in step 4.3, set the linear speed of the abrasive belt Vc = 350m / min, feed F = 300mm / min. The linear speed of the grinding and polishing wheel Vc = 250m / min, feed F = 250mm / min.

[0064] Step 5: Program the grinding and polishing program

[0065] The grinding and polishing program is programmed using general programming software, and the abrasive belt grinding and polishing and grinding and polishing wheel grinding and polishing are programmed according to the milling processing method. The post-processing of the program adopts the post-processing environment of the robot grinding and polishing equipment, and the program format can be run by the robot grinding and polishing equipment.

[0066] Step 6: Grinding and polishing pressure setting

[0067] Grinding and polishing pressure Under the conditions set in step 4.3, the contact pressure between the abrasive belt and the blade is 0.6 bar, and the contact pressure between the grinding and polishing wheel and the blade is 5 bar.

[0068] Step 7: Robot position calibration

[0069] When the grinding wheel is stationary, call the grinding and polishing routine. In the manual low-speed state, observe the corresponding relationship between the robot's posture and the grinding wheel. The robot's moving speed ratio is selected as 10%, and no collision occurs by observing the change of point positions.

[0070] Step 8: Grinding and polishing

[0071] The grinding and polishing test process is carried out in a single step to observe whether there is collision and vibration. After grinding and polishing, the surface state and integrity analysis are carried out to check whether the contour size and surface roughness meet the requirements.

Claims

1. A process for grinding and polishing the entire surface of a blade by a robot, characterized in that: It includes the following steps: Step 1: Plan the division of the blade grinding and polishing areas according to the blade structure According to the structural design characteristics of the blade, the entire blade is respectively planned as the flow channel surface, transition R, leading edge profile, trailing edge profile, basin side profile, back side profile, corner, milling cutter corner trace, and tool joint mark; Step 2: Plan the grinding and polishing strategy Use a grinding and polishing wheel for grinding and polishing. Its grinding and polishing strategy: basin side corner a → basin side corner b → basin side corner c → basin side corner d → milling cutter corner trace → basin side small end root profile → basin side large end root profile → basin side small end root profile → basin side transition R3 → basin side flow channel surface a → basin side transition R3.5 → basin side flow channel surface b → back side corner a → back side corner b → back side corner c → back side corner d → milling cutter corner trace → back side small end root profile → back side large end root profile → back side small end root profile → back side transition R3 → back side flow channel surface a → back side transition R3.5 → back side flow channel surface b; Step 3: Plan the grinding and polishing strategy Use a sand belt for grinding and polishing. Its grinding and polishing strategy: basin side tool joint mark a → basin side tool joint mark b → back side tool joint mark a → back side tool joint mark b → leading edge R → trailing edge R → basin side profile → back side profile; Step 4: Select the grinding and polishing tools and parameters Perform the selection steps of the grinding and polishing wheel, sand belt, sand belt contact wheel, and grinding and polishing parameters in sequence. Step 4.1: Select the grinding and polishing wheel The size of the R of the grinding and polishing wheel needs to be based on the size of the transition R of the grinding and polishing part. The R of the grinding and polishing wheel should be smaller than the transition R of the grinding and polishing part, and the difference between the two is between 0.5 and 1.0 mm; another parameter of the grinding and polishing wheel is the size of its diameter D1. By drawing a diagram to avoid interference, it is calculated that the curvature radius of the grinding and polishing wheel should be smaller than the curvature radius of the grinding and polishing part, that is, D1 < D2; on the premise of meeting this requirement, select a grinding and polishing wheel with a larger diameter, and its diameter is selected as D1 = 30 - 60 mm; Step 4.2: Sand belt, sand belt contact wheel The selection of the sand belt mainly considers two factors. First, the selected sand belt should meet the requirements in terms of material, that is, the material of the sand belt should not contain elements harmful to the polished part. When grinding and polishing titanium alloy materials, sand belts containing elements such as chlorine, copper, brazing, and cadmium cannot be selected. For polishing titanium alloys and superalloys, nylon sand belts, ceramic abrasive sand belts, and zirconium corundum sand belts should be selected; During grinding and polishing, the sand belt contact wheel is used to support the contact between the sand belt and the part. Its parameters are mainly the thickness L, diameter D3, and drum-shaped curvature radius R; the thickness L of the sand belt contact wheel is the same as the width of the sand belt, and is selected according to the size of the part. The thickness of the blade grinding and polishing contact wheel is selected as L = 5 mm or L = 10 mm; the selection method of the diameter D3 is the same as that of the curvature radius of the grinding and polishing wheel in Step 4.1, D3 = 25 mm - 30 mm; the size of the drum-shaped curvature radius R is given according to the curvature of the polished part, R = 20 mm - 25 mm; Step 4.3: Select the grit size of the grinding and polishing tool The grit size of the grinding and polishing wheel is selected according to the amount of material removed. When the amount of material removed is between 0.03 mm and 0.05 mm, the selected grit size is 400# - 600#, and when the amount of material removed is between 0.01 mm and 0.03 mm, the selected grit size is 800# - 1200#; The particle size of the abrasive belt should also be selected according to the removal amount. If the removal amount is between 0.03mm and 0.05mm, the selected particle size is 200# to 300#. If the removal amount is between 0.01mm and 0.03mm, the selected particle size is 400# to 600#. Step 4.4: Grinding and polishing parameter selection The grinding and polishing parameters are mainly linear velocity Vc and feed rate F, which are determined according to the material and removal amount of the parts being ground and polished. Under the conditions of the removal amount set in step 4.3, the linear velocity Vc of the abrasive belt is 300mm / min~350m / min, and the feed rate F is 250mm / min~300mm / min; the linear velocity Vc of the grinding and polishing wheel is 200mm / min~250m / min, and the feed rate F is 200mm / min~250mm / min; Step 5: Program the grinding and polishing program The grinding and polishing program is programmed with general programming software. The abrasive belt grinding and polishing and the grinding and polishing wheel grinding and polishing are programmed according to the milling processing method. The post-processing of the program adopts the post-processing environment of the robot grinding and polishing equipment to process the program into a format that the robot grinding and polishing equipment can receive. Step 6: Grinding and polishing pressure setting The selection of grinding and polishing pressure needs to be combined with the removal amount, feed speed and linear speed. Under the setting conditions in step 4.3, the contact pressure between the abrasive belt and the blade is 0.6 bar to 1.0 bar, and the contact pressure between the grinding and polishing wheel and the blade is 4 bar to 5 bar. Step 7: Robot position calibration When the grinding wheel is stationary, call up the grinding and polishing routine; in the manual low-speed state, observe the corresponding relationship between the posture of the manipulator and the position of the grinding wheel; the moving speed ratio of the manipulator is selected as 10%, which is conducive to accurately observing the position changes and preventing collisions; if the position is abnormal, the enable button of the teach pendant should be released immediately; Step 8: Grinding and polishing During the trial grinding and polishing, a single-step method is adopted. It is necessary to observe whether there is any collision problem at all times. At the same time, it is also necessary to listen to the sound to observe whether there is any vibration. After grinding and polishing, the surface condition and integrity analysis should be carried out to check whether the contour size and surface roughness meet the requirements.

2. The process for grinding and polishing the entire surface of a blade by a robot according to claim 1, characterized in that: In step 1, the boundary between the flow channel surface and the transition R is 1 to 2 mm beyond the transition R; The front and rear edge profile boundary is 2 to 3 mm from the tangent point of the front and rear edge R; The remaining part of the profile is divided into the basin side profile and the dorsal side profile; The corners are the four corners of the blade profile, which need to be polished separately; The cutting marks are the program indirect cutters in the blade profile finishing process, and there are two cutting marks on the profile surface.

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