A Wall Thickness Control Method for a Hollow Single Crystal Blade

Abstract

The present invention discloses a method for controlling the wall thickness of a hollow single crystal blade, which combines the use of a wall thickness adjustment template and a micrometer to control the core offset. The wall thickness adjustment mechanism consists of a positioning metal ejector pin, a wall thickness adjustment metal ejector pin, a wall thickness adjustment template, a micrometer, and a transmission mechanism. The specific method includes the following steps: S1. Clamp the core on the wax mold preparation mold using the positioning metal ejector pin; S2. Press the wax part for the first time and determine the offset to be adjusted according to the expected value; S3. Adjust the wall thickness at the tip part of the core; S4. Adjust the wall thickness at the blade part of the core; S5. Adjust the wall thickness at the dovetail part of the core; S6. Press the wax part again and measure the wall thickness of the blade wax mold. This method can play a positive role in controlling the wall thickness and geometric and positional accuracy of the hollow single crystal blade. It can improve the casting qualification rate of the blade, shorten the model development cycle, and reduce the development cost.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing single-crystal turbine blades without machining allowance by investment casting method, and particularly relates to a method for controlling the wall thickness of hollow single-crystal blades. Background Art

[0002] With the development of aero-engines, the performance requirements for turbine blades of hot-end components are getting higher and higher. The design structure of turbine blades is becoming more and more complex, and the process requirements are getting higher and higher. Hollow single-crystal blades with complex air-cooling structures have become the mainstream of new engine turbine blades.

[0003] The research on the wall thickness control process of hollow single-crystal blades has always been one of the technical problems to be tackled in the industry. The uniformity of the wall thickness depends on the theoretical placement position of the core in the mold. In order to achieve uniform wall thickness in the basin and back directions, the wall thickness control of the previous hollow blade wax patterns used the method of pasting resin core supports on the surface of the core to adjust the position of the core in the mold. This method has a cumbersome manual operation process, the core supports are easy to fall off, and the positioning effect is poor. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method for controlling the wall thickness of hollow single-crystal blades. By setting adjustable metal ejector pins on the mold to control the wall thickness, and combining the use of a wall thickness adjustment template and a micrometer to control the core offset, the process adjustment of the wall thickness of the wax part is realized, thereby improving the wall thickness uniformity of the blade, reducing the wall thickness out-of-tolerance of the blade, and improving the dimensional accuracy of the blade.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for controlling the wall thickness of hollow single-crystal blades, which specifically includes the following steps:

[0007] S1. Clamp the core on the wax pattern preparation mold using positioning metal ejector pins;

[0008] S2. Press the wax part for the first time and determine the offset to be adjusted according to the expected value;

[0009] S3. Adjust the wall thickness at the tip part of the core;

[0010] S4. Adjust the wall thickness at the blade part of the core;

[0011] S5. Adjust the wall thickness at the dovetail part of the core;

[0012] S6. Press the wax part again and measure the wall thickness of the blade wax pattern.

[0013] In step S1, the mold is composed of movable blocks and is a tooling for preparing the wax mold for molding, including positioning metal ejector pins, wall thickness adjusting metal ejector pins, adjusting screws and a transmission mechanism; a core is placed inside the mold, and the positioning metal ejector pins are arranged on the mold movable blocks corresponding to the tip of the core blade, the intake edge of the core, and the extended section of the dovetail teeth, namely the tip positioning metal ejector pin, the intake edge positioning metal ejector pin, and the dovetail teeth extended section positioning metal ejector pin, to ensure that the core is stably placed in the mold in the XOZ direction.

[0014] In step S2, start the wax injection equipment and press the wax part for the first time. Use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part, observe the wall thickness measurement result, and determine the offset direction and offset amount to be adjusted for the tip, blade body, and dovetail teeth parts of the core according to the expected value.

[0015] In step S3, four wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the basin and back directions of the core, namely the tip metal ejector pin 1, the tip metal ejector pin 2, the tip metal ejector pin 3, and the tip metal ejector pin 4, with evenly distributed positions, two in the basin direction and two in the back direction, to ensure the balanced force on the core. Before adjustment, place the wall thickness adjustment template on the mold movable block, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the tip part of the wall thickness adjustment template, and record the dial indicator measurement reading, which is the initial position of the tip metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism at the tip part of the mold to drive the tip metal ejector pin to move up or down. After the direction is adjusted, control the offset amount of the tip metal ejector pin through the dial indicator measurement reading to reach the expectation in step S2, and complete the wall thickness adjustment operation for the tip part of the core.

[0016] In step S4, four wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the basin and back directions of the core, namely the blade body metal ejector pin 1, the blade body metal ejector pin 2, the blade body metal ejector pin 3, and the blade body metal ejector pin 4, with evenly distributed positions, two in the basin direction and two in the back direction, to ensure the balanced force on the core. Before adjustment, place the wall thickness adjustment template on the mold movable block, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the blade body part of the wall thickness adjustment template, and record the dial indicator measurement reading, which is the initial position of the blade body metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism at the blade body part of the mold to drive the blade body metal ejector pin to move up or down. After the direction is adjusted, control the offset amount of the blade body metal ejector pin through the dial indicator measurement reading to reach the expectation in step 2, and complete the wall thickness adjustment operation for the blade body part of the core.

[0017] In step S5, three wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the core basin and back directions, namely the tenon tooth metal ejector pin 1, the tenon tooth metal ejector pin 2, and the tenon tooth metal ejector pin 3. They are evenly distributed in position, with two in the basin direction and one in the back direction to ensure balanced force on the core. Before adjustment, first place the wall thickness adjusting template on the mold movable block, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the tenon tooth part of the wall thickness adjusting template, and record the dial indicator measurement reading, which is the initial position of the tenon tooth metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism at the tenon tooth part of the mold to drive the tenon tooth metal ejector pin to deflect upward or downward. After the direction is adjusted, control the deflection amount of the tenon tooth metal ejector pin through the dial indicator measurement reading to meet the expectation in step 2 and complete the wall thickness adjustment operation at the tenon tooth part.

[0018] In step S6, after the wall thicknesses of the blade tip, blade body, and tenon teeth are all adjusted, start the wax injection equipment and press the wax part again. Use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part again. If the wall thickness is qualified, the adjustment operation can be ended. If it is unqualified, repeat the above steps until the wall thickness of the wax mold is completely qualified.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The research and development projects of hollow single-crystal blade castings are increasing continuously, and the requirements for the dimensional accuracy of the blades are also getting higher and higher. This process method can play an active role in controlling the wall thickness and shape and position accuracy of hollow single-crystal blades. It improves the casting qualification rate of the blades, shortens the model research and development cycle, and reduces the research and development cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall mold for preparing the wax mold of the present invention;

[0022] Figure 2 It is a schematic diagram of the distribution of the wall thickness adjustment mechanism in the mold of the present invention;

[0023] Figure 3 It is a schematic diagram of the positioning metal ejector pin of the present invention;

[0024] Figure 4 It is a schematic diagram of the wall thickness adjusting metal ejector pin of the present invention;

[0025] Figure 5 It is a schematic diagram of the wall thickness adjusting template and the measuring rod of the present invention.

[0026] Among them, 1 - wall thickness adjustment metal ejector pin, 2 - positioning metal ejector pin, 3 - adjusting screw and transmission mechanism, 4 - micrometer, 5 - wall thickness adjustment template, 6 - tip positioning metal ejector pin, 7 - leading edge positioning metal ejector pin, 8 - dovetail extension section positioning metal ejector pin, 9 - tip metal ejector pin 1, 10 - tip metal ejector pin 2, 11 - blade body metal ejector pin 1, 12 - blade body metal ejector pin 2, 13 - dovetail metal ejector pin 1, 14 - tip metal ejector pin 3, 15 - tip metal ejector pin 4, 16 - blade body metal ejector pin 3, 17 - blade body metal ejector pin 4, 18 - dovetail metal ejector pin 2, 19 - dovetail metal ejector pin 3, 20 - measuring rod. Detailed implementation mode

[0027] In order to solve the problems existing in the prior art, such as Figures 1 - 5 As shown, the present invention provides a method for controlling the wall thickness of a hollow single crystal blade, specifically including the following steps:

[0028] S1. Clamp the core using the positioning metal ejector pin 2 on the wax mold preparation mold;

[0029] S2. Initially press the wax part, and determine the offset to be adjusted according to the expected value;

[0030] S3. Adjust the wall thickness at the tip part of the core;

[0031] S4. Adjust the wall thickness at the blade body part of the core;

[0032] S5. Adjust the wall thickness at the dovetail part of the core;

[0033] S6. Press the wax part again and measure the wall thickness of the blade wax mold.

[0034] In step S1, the mold is composed of movable blocks and is a tool for preparing the wax mold to be formed, including the positioning metal ejector pin 2, the wall thickness adjustment metal ejector pin 1, and the adjusting screw and transmission mechanism 3; the core is placed inside the mold, and the positioning metal ejector pin 2 is arranged on the mold movable blocks corresponding to the tip of the core, the leading edge of the core, and the dovetail extension section, namely the tip positioning metal ejector pin 6, the leading edge positioning metal ejector pin 7, and the dovetail extension section positioning metal ejector pin 8, to ensure that the core is stably placed in the mold in the XOZ direction.

[0035] In step S2, start the wax injection equipment and initially press the wax part. Use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part, observe the wall thickness measurement result, and determine the offset direction and offset amount to be adjusted for the tip, blade body, and dovetail parts of the core according to the expected value.

[0036] In step S3, four wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the basin and back directions of the core, namely the first tip metal ejector pin 9, the second tip metal ejector pin 10, the third tip metal ejector pin 14, and the fourth tip metal ejector pin 15. Their positions are evenly distributed, with two on the basin side and two on the back side, ensuring the balanced force on the core. Before adjustment, first place the wall thickness adjusting template 5 on the mold movable block, place the dial indicator 4 at the measuring rod 20 corresponding to the metal ejector pin at the tip part of the wall thickness adjusting template 5, and record the measured reading of the dial indicator 4, which is the initial position of the tip metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism 3 at the tip part of the mold, driving the tip metal ejector pin to shift up or down. After the direction is adjusted, control the offset of the tip metal ejector pin through the measured reading of the dial indicator 4 to reach the expectation in step S2, and complete the wall thickness adjustment operation of the tip part of the core.

[0037] In step S4, four wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the basin and back directions of the core, namely the first blade metal ejector pin 11, the second blade metal ejector pin 12, the third blade metal ejector pin 16, and the fourth blade metal ejector pin 17. Their positions are evenly distributed, with two on the basin side and two on the back side, ensuring the balanced force on the core. Before adjustment, first place the wall thickness adjusting template 5 on the mold movable block, place the dial indicator 4 at the measuring rod 20 corresponding to the metal ejector pin at the blade part of the wall thickness adjusting template 5, and record the measured reading of the dial indicator 4, which is the initial position of the blade metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism 3 at the blade part of the mold, driving the blade metal ejector pin to shift up or down. After the direction is adjusted, control the offset of the blade metal ejector pin through the measured reading of the dial indicator 4 to reach the expectation in step 2, and complete the wall thickness adjustment operation of the blade part of the core.

[0038] In step S5, three wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the basin and back directions of the core, namely the first tenon tooth metal ejector pin 13, the second tenon tooth metal ejector pin 18, and the third tenon tooth metal ejector pin 19. Their positions are evenly distributed, with two on the basin side and one on the back side, ensuring the balanced force on the core. Before adjustment, first place the wall thickness adjusting template 5 on the mold movable block, place the dial indicator 4 at the measuring rod 20 corresponding to the metal ejector pin at the tenon tooth part of the wall thickness adjusting template 5, and record the measured reading of the dial indicator 4, which is the initial position of the tenon tooth metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism 3 at the tenon tooth part of the mold, driving the tenon tooth metal ejector pin to shift up or down. After the direction is adjusted, control the offset of the tenon tooth metal ejector pin through the measured reading of the dial indicator 4 to reach the expectation in step 2, and complete the wall thickness adjustment operation of the tenon tooth part.

[0039] In step S6, after the wall thicknesses of the blade tip, blade body, and dovetail teeth are adjusted, start the wax injection equipment, press the wax part again, and use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part again. If the wall thickness is qualified, the adjustment operation can be ended. If it is unqualified, repeat the above steps until the wall thickness of the wax mold is completely qualified.

Claims

1. A method for controlling the wall thickness of a hollow single-crystal blade, characterized in that: Specifically, it includes the following steps: S1. Clamp the core using positioning metal ejector pins on the wax mold preparation die; S2. Press the wax part for the first time and determine the offset to be adjusted according to the expected value; S3. Adjust the wall thickness at the tip part of the core; S4. Adjust the wall thickness at the blade part of the core; S5. Adjust the wall thickness at the dovetail part of the core; S6. Press the wax part again and measure the wall thickness of the blade wax mold; In step S1, the die is composed of movable blocks and is a tooling for preparing the wax mold. It includes positioning metal ejector pins, wall thickness adjusting metal ejector pins, adjusting screws and a transmission mechanism; the core is placed inside the die, and the positioning metal ejector pins are arranged on the movable blocks of the die corresponding to the tip part of the core, the leading edge of the core, and the dovetail extension part, namely the tip positioning metal ejector pin, the leading edge positioning metal ejector pin, and the dovetail extension positioning metal ejector pin, to ensure that the core is stably placed in the die in the XOZ direction; In step S3, four wall thickness adjusting metal ejector pins are arranged on the movable blocks of the die in the basin and back directions of the core, namely the tip metal ejector pin 1, the tip metal ejector pin 2, the tip metal ejector pin 3, and the tip metal ejector pin 4, with evenly distributed positions, two in the basin direction and two in the back direction, to ensure the balanced force on the core; before adjustment, place the wall thickness adjusting template on the movable block of the die, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the tip part of the wall thickness adjusting template, and record the dial indicator measurement reading, which is the initial position of the tip metal ejector pin here; according to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and the transmission mechanism at the tip part of the die to drive the tip metal ejector pin to move up or down; after the direction is adjusted, control the offset of the tip metal ejector pin through the dial indicator measurement reading to reach the expectation in step S2, and complete the wall thickness adjustment operation at the tip part of the core.

2. A wall thickness control method for a hollow single crystal blade according to claim 1, characterized in that: In step S2, start the wax injection equipment and press the wax part for the first time; use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part, observe the wall thickness measurement result, and determine the offset direction and offset amount to be adjusted at the tip, blade, and dovetail parts of the core according to the expected value.

3. A wall thickness control method for a hollow single crystal blade according to claim 1, characterized in that: In step S4, four wall thickness adjusting metal ejector pins are arranged on the movable blocks of the die in the basin and back directions of the core, namely the blade metal ejector pin 1, the blade metal ejector pin 2, the blade metal ejector pin 3, and the blade metal ejector pin 4, with evenly distributed positions, two in the basin direction and two in the back direction, to ensure the balanced force on the core; before adjustment, place the wall thickness adjusting template on the movable block of the die, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the blade part of the wall thickness adjusting template, and record the dial indicator measurement reading, which is the initial position of the blade metal ejector pin here; according to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and the transmission mechanism at the blade part of the die to drive the blade metal ejector pin to move up or down; after the direction is adjusted, control the offset of the blade metal ejector pin through the dial indicator measurement reading to reach the expectation in step 2, and complete the wall thickness adjustment operation at the blade part of the core.

4. A wall thickness control method for a hollow single crystal blade according to claim 1, characterized in that: In step S5, three wall thickness adjusting metal ejector pins are arranged on the mold movable blocks in the core basin and back directions, namely tenon tooth metal ejector pin 1, tenon tooth metal ejector pin 2, and tenon tooth metal ejector pin 3, which are evenly distributed in position, two in the basin direction and one in the back direction, to ensure balanced force on the core. Before adjustment, first place the wall thickness adjusting template on the mold movable block, place the dial indicator at the measuring rod corresponding to the metal ejector pin at the tenon tooth part of the wall thickness adjusting template, and record the measuring reading of the dial indicator, that is, the initial position of the tenon tooth metal ejector pin here. According to the adjustment direction determined in step 2, use a wrench to rotate the adjusting screw and transmission mechanism at the tenon tooth part of the mold to drive the tenon tooth metal ejector pin to deflect upward or downward. After the direction is adjusted, control the deflection amount of the tenon tooth metal ejector pin through the measuring reading of the dial indicator to achieve the expectation in step 2 and complete the wall thickness adjustment operation of the tenon tooth part.

5. A wall thickness control method for a hollow single crystal blade according to claim 1, characterized in that: In step S6, after the wall thicknesses of the blade tip, blade body, and tenon tooth are all adjusted, start the wax injection equipment, press the wax part again, use an ultrasonic wall thickness measuring instrument to measure the wall thickness of the pressed wax part again. If the wall thickness is qualified, end the adjustment operation; if not, repeat the above steps until the wall thickness of the wax mold is completely qualified.

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