A new method for machining the locking groove of the last blade using a planing and slotting machine

Abstract

A novel method for machining a locking groove for a final blade using a planing and slotting machine relates to the technical field of machining diamond-shaped locking grooves for steam turbine rotors. The invention aims to address the problems of the existing methods for machining the locking groove for the final blade, such as the tendency of the tool to break when machining sharp angles, resulting in puncture damage to the locking groove and poor verticality of the locking groove. The method comprises the following steps: Step 1: Drawing a CAD drawing of a diamond-shaped quadrilateral of the locking groove to be machined, including the workpiece to be machined at the left and right ends of the locking groove and the tool feed space, wherein the workpiece to be machined is divided into an acute-angled triangle portion, a rectangular portion, and an obtuse-angled triangle portion; Step 2: Selecting a tool, wherein the tool selects a rough inserting tool. The invention is used for machining the locking groove for the final blade of a steam turbine rotor, and sequentially reduces the machining allowance through rough machining, semi-finishing machining, and finishing machining, thereby ensuring machining efficiency and preventing the possibility of tool breakage when machining sharp angles.

Description

Technical Field

[0001] The invention relates to the technical field of machining diamond-shaped locking grooves of steam turbine rotors, in particular to a method for machining the locking grooves of last blades using a novel planing and slotting machine. Background Art

[0002] The blade lock groove at the end of the inverted trapezoidal root slot of a steam turbine rotor is typically a diamond-shaped quadrilateral structure and is typically machined using a planer. When machining on a CNC planer, the appropriate slotting tool is selected based on the acute and obtuse angles of the diamond-shaped quadrilateral lock groove. A dedicated CNC program is then compiled based on the slot dimensions. The diamond-shaped quadrilateral lock groove has one pair of obtuse and one pair of acute angles. To achieve the desired angles, a diamond-shaped quadrilateral slotting tool with the same angles is used to ensure the final angle of the quadrilateral lock groove.

[0003] However, when the tool processes the diamond-shaped sharp-angled part of the locking groove, due to the thin structure and poor strength of the tool tip, and the concentrated cutting allowance at the sharp-angled part, the tool is subjected to strong impact during processing and often breaks when processing the sharp-angled part, causing the tool fragments to pierce the locking groove; at the same time, due to the tool letting go during processing, there is a slight verticality difference between the groove mouth and the groove bottom. Summary of the Invention

[0004] The present invention aims to solve the problems of the existing method for machining the locking groove of the last blade, such as the easy breakage of the tool when machining the sharp angle, resulting in the locking groove being punctured and the poor verticality of the locking groove, and further provides a new method for machining the locking groove of the last blade on a planing and slotting machine to solve the problems raised in the above background technology.

[0005] The technical solution of the present invention is:

[0006] A novel method for machining a locking groove of a final blade using a planing and slotting machine comprises the following steps:

[0007] Step 1: Draw a CAD drawing of the diamond-shaped quadrilateral of the lock mouth to be processed, including the workpieces to be processed and the feed space at the left and right ends of the lock mouth, where the workpiece to be processed is divided into an acute-angled triangle part, a rectangular part, and an obtuse-angled triangle part;

[0008] Step 2: Clamp the workpiece, select the tool, and select the rough insert tool;

[0009] Step 3: Rough-process the rectangular part of the workpiece in the lock diamond quadrilateral. The rough inserting tool enters from the feed space. The tool cutting starting point is the acute angle side of the feed space. The rough inserting tool reciprocates along a serpentine trajectory to process. Finally, the processing ends at a 0.1mm margin from the rectangle of the straight edge, and the tool exits from the feed space.

[0010] Step 4: Replace the tool and select the fine insert tool;

[0011] Step 5: Semi-finishing the acute-angled triangle of the workpiece to be processed in the lock diamond quadrilateral. The fine inserting tool enters from the feed space and uses the acute-angled tool to cut. During processing, the acute-angled tool is parallel to the two sides of the acute-angled tool of the lock diamond quadrilateral. The tool moves from right to upper left, cutting 0.05mm per cut. Finally, a 0.5mm allowance is left on the upper bevel and a 0.2mm allowance is left on the right-angled side of the straight side. The tool exits from the feed space.

[0012] Step 6: Semi-finishing the obtuse triangle part of the workpiece to be processed in the lock diamond quadrilateral. The fine inserting tool enters from the feed space and uses the obtuse tool part for cutting. During processing, the obtuse tool part is parallel to the two sides of the obtuse tool part of the lock diamond quadrilateral. The tool moves from right to upper left, cutting 0.05mm per cut. Finally, a 0.5mm allowance is left on the lower bevel, and a 0.1mm allowance is left at the acute angle vertex of the triangle at the lower end of the straight side. The tool exits from the feed space.

[0013] Step 7: Finish machining the allowance at the acute angle of the workpiece. The fine inserting tool enters from the feed space and uses the acute angle part of the tool to cut. During machining, the cutting edge of the acute angle side of the fine inserting tool coincides with the upper bevel. The fine inserting tool processes along the upper bevel toward the vertex of the acute angle part. Each cut cuts 0.2mm. The machining is completed when the distance between the straight edge of the fine inserting tool and the straight edge of the lock diamond quadrilateral is 0.1mm, and the tool withdraws.

[0014] Step 8: Finish machining the allowance at the obtuse angle of the workpiece. The fine inserting tool enters from the feed space and uses the obtuse angle part of the tool to cut. During machining, the cutting edge of the obtuse angle side of the fine inserting tool coincides with the lower bevel. The fine inserting tool processes along the lower bevel toward the vertex of the obtuse angle part. Each cut cuts 0.2mm until the obtuse angle part of the tool coincides with the obtuse angle part of the lock mouth diamond quadrilateral and the straight edge of the fine inserting tool coincides with the straight edge of the lock mouth diamond quadrilateral.

[0015] Then the fine inserting tool moves along the straight edge from bottom to top, cutting 0.2mm per cut, until the acute angle part of the tool coincides with the acute angle parts of the four sides of the lock rhombus. The fine inserting tool moves along the straight edge from top to bottom again, cutting until the obtuse angle part of the tool coincides with the obtuse angle parts of the four sides of the lock rhombus. Finally, the fine inserting tool moves along the straight edge again from bottom to top, cutting 0.2mm per cut, until the acute angle part of the tool coincides with the acute angle parts of the four sides of the lock rhombus. This completes three reciprocating turning cycles.

[0016] Step 9. According to the methods of steps 2 to 8, process the area of ​​the workpiece to be processed on the symmetrical side of the four sides of the lock diamond to complete the processing of the entire four sides of the lock diamond.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] A novel method for machining the locking groove of the final blade using a planing and slotting machine is described. The locking groove of the final blade of a steam turbine rotor is machined using a planing and slotting machine. The machining of the locking groove is divided into roughing, semi-finishing, and finishing after leaving a small amount of allowance. A roughing tool is used to machine the rectangular portion of the workpiece, followed by a fine tool to machine the acute and obtuse triangles. Finally, a fine tool is used to machine the remaining allowance. Reducing the feed rate when using the fine tool significantly reduces the tool's cutting force during finishing. This prevents tool breakage at the sharp corners of the locking rhombus or quadrilateral, thus preventing the fine tool from breaking. Through roughing, semi-finishing, and finishing, the machining allowance is reduced sequentially, ensuring machining efficiency while preventing tool breakage when machining sharp corners.

[0019] In existing machining techniques, the straight edges of the diamond-shaped quadrilateral of the lock slot are machined in one pass. During machining, the tool is subjected to cutting resistance, causing the tool to give up when machining from the slot mouth to the slot bottom. This results in inaccurate bottom machining dimensions and causes the machined surface member 9 to be non-perpendicular to the bottom surface. The present invention utilizes a three-pass reciprocating machining method for the straight edges of the diamond-shaped quadrilateral of the lock slot. This machining method can accurately correct the tool giving up portion of the machined surface and ensure that the perpendicularity between the straight edges and the slot bottom after machining is controlled within 0.02, meeting the requirements of the lock slot design drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the diamond-shaped quadrilateral of the lock mouth of the present invention;

[0021] Figure 2 This is a schematic diagram of the rough processing of the diamond-shaped quadrilateral of the lock mouth of the present invention;

[0022] Figure 3 This is a schematic diagram of the semi-finishing of the sharp angle of the diamond-shaped quadrilateral of the lock mouth of the present invention;

[0023] Figure 4 yes Figure 3 A partial enlarged view of

[0024] Figure 5 This is a schematic diagram of the semi-finishing of the obtuse angle of the lock rhombus quadrilateral of the present invention;

[0025] Figure 6 yes Figure 5 A partial enlarged view of

[0026] Figure 7 This is a schematic diagram of the rough insert structure of the present invention;

[0027] Figure 8 This is a schematic diagram of the structure of the precision inserting knife of the present invention;

[0028] Figure 9 It is a schematic diagram of the precision processing of the diamond-shaped quadrilateral of the lock mouth of the present invention.

[0029] In the figure: 1, acute-angled part; 2, obtuse-angled part; 3, part to be machined; 4, feed space; 5, roughing tool part; 6, fine-slotting tool part; 7, acute-angled tool part; 8, obtuse-angled tool part; 9, straight edge; 10, upper bevel; 11, upper triangular part I; 12, upper triangular part II; 13, upper triangular part III; 14, lower bevel; 15, lower triangular part I; 16, lower triangular part II; 17, lower triangular part III; H1, width to be machined; H2, feed space width; H3, roughing tool cutting width; H4, overall roughing tool width; H5, fine-slotting tool cutting width; H6, overall fine-slotting tool width; H7, roughing cutting depth; H9, upper triangular area machining width; H10, lower triangular area machining width; H11, fine-slotting tool width; D1, bevel edge allowance; D2, straight edge allowance. DETAILED DESCRIPTION

[0030] Specific implementation method 1: See Figure 1-9 As shown, a novel method for machining the locking groove of the last blade on a planing machine is provided. This embodiment comprises the following steps:

[0031] Step 1: Draw a CAD drawing of the diamond-shaped quadrilateral of the lock mouth to be processed, including the workpiece 3 to be processed and the feed space 4 at the left and right ends of the lock mouth, where the workpiece 3 to be processed is divided into an acute-angled triangle part, a rectangular part, and an obtuse-angled triangle part;

[0032] Step 2: Clamp the workpiece and select the tool, which is the rough inserting tool 5;

[0033] Step 3: Rough-process the rectangular portion of the workpiece 3 in the lock diamond quadrilateral. The rough inserting tool 5 enters from the feed space 4. The tool cutting starting point is the acute angle side of the feed space 4. The rough inserting tool 5 reciprocates along a serpentine trajectory to process. Finally, the processing ends at the rectangle with a 0.1mm margin from the straight edge 9. The tool then exits from the feed space 4.

[0034] Step 4: Replace the tool and select the fine inserting tool 6;

[0035] Step 5: Semi-finishing the acute triangle part of the workpiece 3 in the lock diamond quadrilateral. The fine inserting tool 6 enters from the feed space 4 and uses the acute angle tool 7 for cutting. During processing, the acute angle tool 7 is parallel to the two sides of the acute angle part 1 of the lock diamond quadrilateral. The tool moves from right to upper left, cutting 0.05mm per cut. Finally, a 0.5mm allowance is left on the upper bevel 10, and a 0.2mm allowance is left on the upper right-angled side of the straight edge 9. The tool exits from the feed space 4.

[0036] Step 6, semi-finishing the obtuse triangle part of the workpiece 3 to be processed in the lock diamond quadrilateral, the fine inserting tool 6 enters from the feed space 4, and uses the tool obtuse angle part 8 for cutting. During processing, the tool obtuse angle part 8 is parallel to the two sides of the obtuse angle part 2 of the lock diamond quadrilateral, and the tool moves from right to upper left, cutting 0.05mm per cut, and processing to the lower bevel 14 with a 0.5mm allowance, and leaving a 0.1mm allowance at the acute angle vertex of the triangle at the lower end of the straight edge 9. Then the fine inserting tool 6 and the straight edge 9 keep 0.1mm and start processing from bottom to top, cutting 0.2mm per cut until the acute angle side is 0.5mm away from the upper bevel 10 of the lock diamond, and leaving a 0.1mm allowance on the straight edge 9, and the tool withdraws from the feed space 4;

[0037] Step 7: Finish machining the allowance at the acute angle of the workpiece 3. The fine inserting tool 6 enters from the feed space 4 and uses the acute angle tool 7 to cut. During machining, the acute angle side cutting edge of the fine inserting tool 6 coincides with the upper bevel 10. The fine inserting tool 6 processes along the upper bevel 10 toward the vertex of the acute angle part 1. Each cut is 0.2 mm. The machining is completed when the distance between the straight edge of the fine inserting tool 6 and the straight edge 9 of the lock diamond quadrilateral is 0.1 mm, and the tool is withdrawn.

[0038] Step 8: Finish machining the allowance at the obtuse angle of the workpiece 3. The fine inserting tool 6 enters from the feed space 4 and uses the obtuse angle tool 8 to cut. During machining, the obtuse angle side cutting edge of the fine inserting tool 6 coincides with the lower bevel 14. The fine inserting tool 6 processes along the lower bevel 14 toward the vertex of the obtuse angle tool 2. Each cut is 0.2 mm. The machining is performed until the obtuse angle tool 8 coincides with the obtuse angle tool 2 of the locking diamond quadrilateral and the straight edge of the fine inserting tool 6 coincides with the straight edge 9 of the locking diamond quadrilateral.

[0039] Then, the fine inserting tool 6 moves along the straight edge 9 from bottom to top, cutting 0.2mm per cut, until the tool acute angle piece 7 overlaps with the acute angle piece 1 of the locking diamond quadrilateral. The fine inserting tool 6 moves along the straight edge 9 from top to bottom again, cutting until the tool obtuse angle piece 8 overlaps with the obtuse angle piece 2 of the locking diamond quadrilateral. Finally, the fine inserting tool 6 moves along the straight edge 9 from bottom to top again, cutting 0.2mm per cut, until the tool acute angle piece 7 overlaps with the acute angle piece 1 of the locking diamond quadrilateral. Three reciprocating turning cycles are completed.

[0040] Step 9: Process the area of ​​the workpiece 3 on the symmetrical side of the lock-mouth diamond-shaped quadrilateral according to the methods of steps 2 to 8, and complete the processing of the entire lock-mouth diamond-shaped quadrilateral.

[0041] Further, first draw the CAD drawing of the lock rhombus quadrilateral to be processed, design and process the precision inserting tool 6 with the same obtuse angle and acute angle as the lock rhombus quadrilateral. Execute to complete step three, according to Figure 2Move the tool in the direction of the arrow on the middle serpentine path. After completing the machining of the rectangular portion of the workpiece 3, the remaining parts to be machined are: the upper acute triangle portion, the lower obtuse triangle portion, and a 0.1mm allowance at the straight edge 9. Execute to step 5 to complete the semi-finishing machining of the acute triangle portion of the workpiece 3. The remaining parts to be machined are: the upper acute triangle straight edge portion with a 0.2mm allowance, the upper bevel 10 with a 0.5mm allowance, the lower obtuse triangle portion, and a 0.1mm allowance at the straight edge 9. Execute to step 6 to complete the semi-finishing machining of the obtuse triangle portion of the workpiece 3. The remaining parts to be machined are: the upper bevel 10 with a 0.5mm allowance, the lower bevel 14 with a 0.1mm allowance, and the straight edge 9 with a 0.1mm allowance. Execute to step 7 to complete the fine machining of the acute angles of the workpiece 3. The remaining parts to be machined are: the lower bevel 14 with a 0.5mm allowance, and the straight edge 9 with a 0.1mm allowance. Execute to step eight to complete the processing of all remaining allowances.

[0042] Furthermore, a roughing tool is used to machine the rectangular portion of the workpiece, followed by a fine-slotting tool for the acute and obtuse triangles, and finally a fine-slotting tool for the remaining stock. This reduces the feed rate when using the fine-slotting tool, significantly reducing the tool's cutting force during fine machining. This prevents tool breakage at the sharp corners of the locking diamond and quadrilateral, thus preventing the fine-slotting tool from breaking. Through roughing, semi-finishing, and fine machining, the stock is reduced sequentially, maximizing machining efficiency.

[0043] Furthermore, in step eight, the last 1mm allowance of the straight edge 9 of the four diamond-shaped rows of the lock groove is processed three times back and forth. This processing method can accurately correct the tool-allowing part of the processing surface and ensure that the verticality of the straight edge and the bottom of the lock groove after processing is controlled within 0.02, meeting the requirements of the lock groove design drawings.

[0044] Specific implementation method 2: See Figure 3-4 As shown, the specific steps of cutting the acute triangle part in step five are as follows:

[0045] Step 51: Calculate the upper triangle area processing width H9;

[0046] Step 52: Divide the upper triangle area processing width H9 into N layers according to the fine insert width H11 for processing. N=H9÷(H11 / 2). If the calculated result shows that the processing width of the last layer is less than 1mm, it can be merged into the previous layer for processing.

[0047] Step 53: If N=3, the upper triangle is divided into three parts: upper triangle part I11, upper triangle part II12, and upper triangle part III13. The tool enters from feed space 4 and processes the upper triangle part I11, upper triangle part II12, and upper triangle part III13 in order.

[0048] Step 54: The fine inserting tool 6 enters from the feed space 4 and is cut using the tool acute angle piece 7. During processing, the tool acute angle piece 7 is parallel to the two sides of the lock diamond quadrilateral acute angle piece 1, and the tool is moved from right to upper left, with each cut cutting 0.05mm. Finally, a 0.5mm margin is left on the upper bevel 10, and a 0.2mm margin is left on the upper triangular right angle side of the straight edge 9. The tool exits from the feed space 4.

[0049] Specific implementation method three: see Figure 5-6 As shown, the specific steps of cutting the obtuse triangle part in step six are as follows:

[0050] Step 61: Calculate the processing width H10 of the lower triangle area;

[0051] Step 62: Divide the lower triangle area processing width H10 into N layers according to the fine insert width H11 for processing. N = H10 ÷ (H11 / 2). If the calculated result shows that the processing width of the last layer is less than 1mm, it can be merged into the previous layer for processing.

[0052] Step 63: If N=3, the lower triangle is divided into three parts: lower triangle part I15, lower triangle part II16, and lower triangle part III17. The tool enters from feed space 4 and processes lower triangle part I15, lower triangle part II16, and lower triangle part III17 in order.

[0053] Step 64: The fine inserting tool 6 enters from the feed space 4 and is cut using the blunt-angle tool part 8. During processing, the blunt-angle tool part 8 is parallel to the two sides of the lock diamond quadrilateral blunt-angle tool 2, and the tool is moved from right to upper left, with each cut cutting 0.05mm. Finally, a 0.5mm margin is left at the lower bevel 14, and a 0.1mm margin is left at the acute angle vertex of the triangle at the lower end of the straight edge 9. The tool exits from the feed space 4.

[0054] Furthermore, the above embodiment specifically describes the semi-finishing method for the acute-angled triangle portion and the obtuse-angled triangle portion. During these two processes, the tool's acute-angled member 7 is parallel to both sides of the locking diamond-shaped quadrilateral acute-angled member 1, and the tool's obtuse-angled member 8 is parallel to both sides of the locking diamond-shaped quadrilateral obtuse-angled member 2. When the tool reaches the end point of the process, the acute-angled member 1 and the obtuse-angled member 2 of the workpiece 3 to be processed form the same angle as the tool's acute-angled member 7 and the tool's obtuse-angled member 8 of the finishing insert 6, thereby determining the angle of the locking groove at the completion of the process.

[0055] Specific implementation method four: see Figure 2 As shown, in step 3 of the present embodiment, when rough machining the rectangular portion of the workpiece 3 in the locking diamond quadrilateral, the rough machining cutting depth H7 in the positive direction of the Z axis is 0.2 mm each time, and the tool is cut downward in the X axis direction first, with a cutting width of 0.05 mm per cut.

[0056] Specific implementation method five: see Figure 2 As shown, in step 2 of this embodiment, the rough insert 5 is selected from a blade whose width to be processed H1 is smaller than the rough insert cutting width H3 and whose overall width H4 is smaller than the feed space width H2.

[0057] Specific implementation method six: see Figure 2 As shown, in step 4 of this embodiment, the fine inserting tool 6 is selected: a blade whose processing width H1 is smaller than the fine inserting tool cutting width H5, and whose overall width H6 of the fine inserting tool is smaller than the feed space width H2 of the feed space 4.

[0058] Specific implementation method seven: See Figure 2 As shown, the precision inserting tool 6 of this embodiment uses: the tool acute angle piece 7 is the same as the locking diamond square acute angle piece 1, and the tool obtuse angle piece 8 is the same as the locking diamond square obtuse angle piece 2.

[0059] Furthermore, the roughing tool 5 is selected to have a cutting width H3 greater than the width to be processed H1, ensuring sufficient processing depth to fully process the width H1. The roughing tool's overall width H4 is smaller than the feed space width H2, ensuring sufficient space for feed and preventing the tool from being unable to penetrate the feed space 4. The same principle applies to the selection of the aforementioned fine inserting tool 6. Fine inserting tool 6 is selected to have a blade with the same acute-angled tool piece 7 as the four-sided acute-angled tool piece 1 for the locking rhombus, and the same blunt-angled tool piece 8 as the four-sided blunt-angled tool piece 2 for the locking rhombus. After processing, the four corners of the locking rhombus form the same angles as the acute-angled tool piece 7 and blunt-angled tool piece 8 of the fine inserting tool 6.

[0060] Specific implementation method eight: see Figure 2 As shown, the method of this embodiment adopts a vertical planer to perform processing.

[0061] Specific implementation method nine: See Figure 2 As shown, the blade material of the rough inserting tool 5 and the fine inserting tool 6 in this embodiment is M42, and the tool body material is 45# steel.

[0062] Specific implementation method ten: See Figure 2 As shown, the specific part of clamping the workpiece in step 1 of this embodiment is as follows:

[0063] Step 1: Insert the shaft diameters at both ends into the support fixtures respectively;

[0064] Step 1 and 2: Use fasteners to tighten the shaft diameter in the support fixture from top to bottom;

[0065] Step 1 and 3: Install protective sleeves on both ends of the shaft diameter, and the workpiece clamping is completed.

Claims

1. A novel method for machining the locking groove of the last blade using a planing and slotting machine, characterized in that: The method has the following steps: Step 1: Draw the diamond-shaped quadrilateral CAD drawing of the lock to be processed. It includes a workpiece (3) to be processed at the left and right ends of the lock mouth and a feed space (4), wherein the workpiece (3) to be processed is divided into an acute-angled triangle part, a rectangular part and an obtuse-angled triangle part; Step 2: Clamp the workpiece and select a tool, which is a rough insert (5); Step 3: Rough-process the rectangular portion of the workpiece (3) to be processed in the lock diamond quadrilateral. The rough inserting tool (5) enters from the feed space (4). The tool cutting starting point is the acute angle side of the feed space (4). The rough inserting tool (5) is processed by reciprocating cutting in a serpentine trajectory. The processing ends at the rectangle with a 0.1mm margin from the straight edge (9). The tool exits from the feed space (4); Step 4: Replace the tool and select the fine insert tool (6); Step 5: Semi-finishing the acute triangle portion of the workpiece (3) to be processed in the lock-mouth rhombus quadrilateral. The fine inserting tool (6) enters from the feed space (4) and uses the acute angle tool (7) to cut. During processing, the acute angle tool (7) is parallel to the two sides of the acute angle tool (1) of the lock-mouth rhombus quadrilateral. The tool is moved from right to upper left, and each cut is 0.05mm. Finally, a 0.5mm margin is left on the upper bevel (10). A 0.2mm margin is left on the upper right-angled side of the straight side (9). The tool is then withdrawn from the feed space (4). Step 6, semi-finishing the obtuse triangle part of the workpiece (3) to be processed in the lock rhombus quadrilateral, the fine inserting tool (6) enters from the feed space (4), and uses the tool obtuse angle part (8) to cut. During processing, the tool obtuse angle part (8) is parallel to the two sides of the lock rhombus quadrilateral obtuse angle part (2), and the tool is moved from right to upper left, cutting 0.05mm per cut, processing to the lower bevel (14) with a 0.5mm margin, and leaving a 0.1mm margin at the triangle acute angle vertex at the lower end of the straight edge (9), then the fine inserting tool (6) and the straight edge (9) keep 0.1mm and start processing from bottom to top, cutting 0.2mm per cut until the acute angle side is 0.5mm away from the lock rhombus upper bevel (10), and leaving a 0.1mm margin on the straight edge (9), and the tool exits from the feed space (4); Step 7, finishing the allowance at the acute angle of the workpiece (3), the fine inserting tool (6) enters from the feed space (4), and uses the tool acute angle piece (7) to cut. During processing, the acute angle side cutting edge of the fine inserting tool (6) coincides with the upper bevel (10), and the fine inserting tool (6) processes along the upper bevel (10) toward the vertex of the acute angle piece (1), cutting 0.2mm per cut. The processing is completed when the distance between the straight edge of the fine inserting tool (6) and the straight edge (9) of the lock diamond quadrilateral is 0.1mm, and the tool is withdrawn; Step eight, finishing the allowance at the obtuse angle of the workpiece (3), the fine inserting tool (6) enters from the feed space (4), and uses the tool obtuse angle piece (8) to cut. During processing, the obtuse angle side cutting edge of the fine inserting tool (6) coincides with the lower bevel (14), and the fine inserting tool (6) is processed along the lower bevel (14) toward the vertex of the obtuse angle piece (2), with each cut cutting 0.2mm, until the tool obtuse angle piece (8) coincides with the lock-mouth rhombus quadrilateral obtuse angle piece (2), and the straight edge of the fine inserting tool (6) coincides with the straight edge (9) of the lock-mouth rhombus quadrilateral; Then the fine inserting tool (6) moves along the straight edge (9) from bottom to top, cutting 0.2mm per cut, until the tool acute angle piece (7) and the lock-mouth rhombus quadrilateral acute angle piece (1) overlap, the fine inserting tool (6) moves along the straight edge (9) from top to bottom again, cutting until the tool blunt angle piece (8) and the lock-mouth rhombus quadrilateral blunt angle piece (2) overlap; finally, the fine inserting tool (6) moves along the straight edge (9) again from bottom to top, cutting 0.2mm per cut, until the tool acute angle piece (7) and the lock-mouth rhombus quadrilateral acute angle piece (1) overlap, completing three reciprocating turnings; Step 9: Process the area of ​​the workpiece (3) on the symmetrical side of the lock-mouth diamond-shaped quadrilateral according to the methods of steps 2 to 8, and complete the processing of the entire lock-mouth diamond-shaped quadrilateral.

2. The method for machining the locking groove of the last blade by a new planing and slotting machine according to claim 1, characterized in that: The specific steps of cutting the acute triangle part in step 5 are as follows: Step 51: Calculate the processing width of the upper triangle area (H9); Step 52: Divide the upper triangle area processing width (H9) into N layers according to the fine insert width (H11) for processing. N = H9 ÷ (H11 / 2). If the calculated result shows that the processing width of the last layer is less than 1mm, it can be merged into the previous layer for processing. Step 53: If N=3, the upper triangle is divided into three parts: upper triangle part I (11), upper triangle part II (12), and upper triangle part III (13). The tool enters from the feed space (4) and processes the upper triangle part I (11), upper triangle part II (12), and upper triangle part III (13) in sequence. Step 54: The fine inserting tool (6) enters from the feed space (4) and is cut using the tool acute angle piece (7). During processing, the tool acute angle piece (7) is parallel to the two sides of the lock diamond quadrilateral acute angle piece (1). The tool is moved from right to upper left, cutting 0.05mm per cut until the upper bevel (10) is processed with a 0.5mm margin and a 0.1mm margin is left at the upper end of the triangle right angle of the straight edge (9). The tool then exits from the feed space (4).

3. The method for machining the locking groove of the last blade using a new planing and slotting machine according to claim 1, characterized in that: The specific steps of cutting the obtuse triangle part in step 6 are as follows: Step 61: Calculate the processing width of the lower triangle area (H10); Step 62: Divide the lower triangle area processing width (H10) into N layers according to the fine insert width (H11) for processing. N = H10 ÷ (H11 / 2). If the calculated result shows that the processing width of the last layer is less than 1mm, it can be merged into the previous layer for processing. Step 63: If N=3, the lower triangle is divided into three parts: lower triangle part I (15), lower triangle part II (16), and lower triangle part III (17). The tool enters from the feed space (4) and processes the lower triangle part I (15), lower triangle part II (16), and lower triangle part III (17) in sequence. Step 64: The fine inserting tool (6) enters from the feed space (4) and is cut using the blunt-angle tool (8). During processing, the blunt-angle tool (8) is parallel to the two sides of the lock rhombus quadrilateral blunt-angle tool (2). The tool is moved from right to upper left, with each cut cutting 0.05mm. Finally, a 0.5mm margin is left at the lower bevel (14) and a 0.1mm margin is left at the acute angle vertex of the triangle at the lower end of the straight edge (9). The tool then exits from the feed space (4).

4. The method for machining the locking groove of the last blade by a new planing and slotting machine according to claim 1, characterized in that: Step 3: When rough machining the rectangular part of the workpiece (3) in the lock diamond quadrilateral, the rough machining cutting depth (H7) in the positive direction of the Z axis is 0.2 mm each time, and the tool is cut downward in the X axis direction first, with a cutting width of 0.05 mm per cut.

5. The method for machining the locking groove of the last blade by a new planing and slotting machine according to claim 1 is characterized in that: In step 2, the rough insert (5) is selected from blades having a width to be processed (H1) smaller than the rough insert cutting width (H3) and an overall width (H4) of the rough insert smaller than the feed space width (H2).

6. The method for machining the locking groove of the last blade using a new planing and slotting machine according to claim 1, characterized in that: In step 4, the fine inserting tool (6) is selected from: a blade whose width to be processed (H1) is smaller than the fine inserting tool cutting width (H5), and whose overall width (H6) of the fine inserting tool is smaller than the feed space width (H2) of the feed space (4).

7. The method for machining the locking groove of the last blade using a new planing and slotting machine according to claim 6, characterized in that: The precision inserting tool piece (6) is selected from the following: the acute angle piece (7) of the tool is the same as the acute angle piece (1) of the locking rhombus quadrilateral, and the blunt angle piece (8) of the tool is the same as the blunt angle piece (2) of the locking rhombus quadrilateral.

8. The method for machining the locking groove of the last blade using a new planing and slotting machine according to claim 1, characterized in that: The method adopts a vertical planing machine for processing.

9. The novel planing and slotting machine method for processing the locking groove of the last blade according to claim 1, characterized in that: The blade material of the rough inserting knife piece (5) and the fine inserting knife piece (6) is M42, and the knife body material is 45# steel.

10. The novel planing and slotting machine method for processing the locking groove of the last blade according to claim 1, characterized in that: The specific parts of clamping the workpiece in step 1 are as follows: Step 1: Insert the shaft diameters at both ends into the support fixtures respectively; Step 1 and 2: Use fasteners to tighten the shaft diameter in the support fixture from top to bottom; Step 1 and 3: Install protective sleeves on both ends of the shaft diameter, and the workpiece clamping is completed.

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