Method for correcting core deviation and deformation of engine blade ceramic core

Abstract

The application discloses a method for correcting the deviation and deformation of an engine blade ceramic core, which comprises the following steps: taking a plurality of wall thickness detection sections on the blade type of a casting, specifying wall thickness detection points and measuring the position wall thickness, determining the wall thickness deviation at the wall thickness detection points by using the tangent circle method; copying and extracting the inner cavity structure profile of the blade section profile and gluing, and cutting and constraining the glued inner cavity structure profile and the three actually measured wall thickness circles with the largest deviation; comparing the difference between the inner cavity profile curves, analyzing whether the ceramic core is deformed in the casting process, measuring the deformation trend and deformation amount, designing the anti-deformation parameters and correcting the mold; the application reversely analyzes the specific size and trend of the deformation and deviation of the ceramic core, quantifies the correction value, reduces the difficulty of the size analysis of the inner cavity of the casting, realizes the accurate control of the inner cavity size, improves the precision of the casting, reduces the trial production times of the casting and reduces the research and development cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision casting, in particular to a method for correcting core deviation and deformation of an engine blade ceramic core. BACKGROUND

[0002] The rapid development of the aerospace, gas turbine, energy and other industries cannot be separated from the improvement of engine development technology. In the engine development technology, the service performance requirements of various types of engine blades are extremely strict. In particular, many blades in aerospace engines must be hollow structures, and the internal structure is complex, the wall thickness size control is strict, and the size, air flow and water flow must be qualified.

[0003] For complex structure and precise size of the cavity blade, the casting difficulty is high and the process cost is high. The complex and precise internal cavity structure is generally fixed in a metal mold by a ceramic core to realize casting forming by investment casting. The extremely high temperature in the investment casting process causes a large stress on the ceramic core, and there is unavoidable stress deformation when the blade is formed. Because the size of the internal cavity structure is very fine, the pin structure for fixing the ceramic core and supporting the ceramic core in the mold has the risk of causing size deviation of the ceramic core placement. Excessive core deviation or deformation of the ceramic core will cause the wall thickness size of the blade to be out of tolerance, directly leading to the rejection of the blade. Therefore, in the casting development process of such blades, the core deviation and deformation of the ceramic core are important size problems to be overcome.

[0004] The existing casting of complex cavity blades is to fix the ceramic core by setting a pin to support the ceramic core in the mold, and then to manufacture the complex cavity blade by investment casting process. The control of the size of the internal cavity of the blade is to set a specified wall thickness detection point on the blade, and to detect the wall thickness of the blade by ultrasonic detection technology, so as to realize the control of the size of the internal cavity.

[0005] If the ceramic core is deformed or deviated during casting, the wall thickness detection of the finished blade will have size deviation. According to the size deviation of each position detection point, the deformation amount or the direction and degree of core deviation of the ceramic core can be judged, and the pin supporting the ceramic core in the wax mold can be adjusted for re-manufacturing and improvement.

[0006] Although the above-mentioned traditional correction method can analyze the amount of core deviation of each position of the blade, due to the irregular shape of the blade profile, the deformation and core deviation problems often exist at the same time, and it is often difficult to quantify the degree of overall deformation and core deviation of the ceramic core in the casting process, and it is also difficult to determine the angle of the core deviation of the ceramic core. The supporting pins and wall thickness detection points in the wax mold do not correspond, and the size deviation of the wall thickness detection point cannot accurately determine how much the supporting pin needs to be corrected, which brings great difficulty to the size control.

[0007] To this end, the application provides a ceramic core deviation and deformation correction method of an engine blade, which is based on the existing ultrasonic measurement wall thickness size technology, specifically quantitatively analyzes the ceramic core deformation and deviation problems in complex cavity blade casting, calculates the anti-deformation amount to be added to the ceramic core and the correction amount at the support pin, realizes accurate control of the inner cavity size, reduces the process trial number, and saves the development cost. SUMMARY

[0008] The main purpose of the application is to provide a ceramic core deviation and deformation correction method of an engine blade, which can effectively solve the problems in the background art.

[0009] To achieve the above purpose, the technical scheme adopted by the application is as follows: a ceramic core deviation and deformation correction method of an engine blade, comprising the following steps:

[0010] S1, according to the blade casting wall thickness detection scheme, a plurality of wall thickness detection sections are taken on the blade type of the casting, a plurality of wall thickness detection points are designed at the specified positions of each detection section, ultrasonic detection technology is used to measure all the wall thickness detection points, and the measured wall thickness values are recorded;

[0011] S2, analyze each wall thickness detection section of the blade casting model through 3D modeling software, make the blade section profile of the wall thickness detection section, express the wall thickness values of the actual measured detection points as measured wall thickness circles by using the tangent circle method, and also draw the theoretical wall thickness circles according to the tangent circle method, compare the measured wall thickness circles and the theoretical wall thickness circles, and determine the deviation of the measured wall thickness size and the theoretical wall thickness size at the wall thickness detection points;

[0012] S3, copy and extract the inner cavity structure profile of the blade section profile, constrain the lines of the inner cavity structure profile as a glued whole, select the three wall thickness detection points with the largest deviation between the measured wall thickness circles and the theoretical wall thickness circles, constrain the glued inner cavity structure profile to be tangent to the three measured wall thickness circles with the largest deviation, and fix the glued inner cavity structure profile through the three constraints;

[0013] S4, compare the original inner cavity profile curve in the blade wall thickness detection section with the extracted and fixed inner cavity structure profile, and analyze whether the ceramic core is deformed in the casting process, and measure the deformation trend and deformation amount;

[0014] S5, after analyzing each wall thickness detection section, overall size difference is considered, anti-deformation parameters are designed through process theory analysis, and the mold is corrected, after correction, a new round of trial analysis is carried out.

[0015] Preferably, the step S4 is analyzed by comparing the original inner cavity profile curve in the blade wall thickness detection section and the chord length angle and displacement size of the extracted and re-constrained inner cavity structure profile, the core deviation direction and displacement of the ceramic core in the wall thickness detection section in the casting process are analyzed, and the specific core deviation size is measured, and the quantitative analysis result is obtained.

[0016] Preferably, in the step S5, after analyzing each wall thickness detection section, the measured wall thickness circular connecting line corresponding to the longitudinal size is compared with the theoretical wall thickness circular connecting line, and the core deviation angle of the ceramic core in the longitudinal direction is measured.

[0017] Preferably, in the step 5, according to the measured core deviation angle and displacement size, the ceramic core model is deflected and moved according to the measured core deviation angle and displacement, the ceramic core model is moved to the position after the core deviation, the correction size of the support pin is measured, and the pin in the wax mold is adjusted.

[0018] Compared with the prior art, the application has the beneficial effects that: the application is applied to the casting process of a complex inner cavity high-precision blade, the measured wall thickness value in the trial production process is analyzed in reverse by a 3D modeling software to obtain the specific size and trend of the ceramic core deformation and core deviation, the correction value is quantified, the difficulty of analyzing the inner cavity size of the casting is reduced, the accurate control of the inner cavity size is realized, the precision of the casting is improved, and the trial production times of the casting are reduced; the thermal stress deformation in the casting process of the complex cavity blade and the core deviation of the ceramic core can be specifically quantitatively analyzed, the computer theoretical calculation and analysis are adopted, and the research and development cost is greatly reduced.

[0019] The measured wall thickness connecting line of each wall thickness detection section is analyzed, the longitudinal core deviation angle of the ceramic core is measured, the analysis of the core deviation of the ceramic core is not limited in one section, and thus the error caused by the longitudinal angle deviation is analyzed.

[0020] The application combines the ultrasonic measurement of the actual casting result, combines the wall thickness value deviation and the correction value of the support pin through the deflection and movement of the ceramic core model, combines the practice and theory, and the correction result of the analysis has high practical value. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a wall thickness detection scheme layout of the blade casting in the application;

[0022] Figure 2 It is a blade section profile analysis schematic diagram in the application;

[0023] Figure 3 It is a ceramic core model schematic diagram in the application;

[0024] Figure 4 It is a blade section profile longitudinal connecting line schematic diagram in the application.

[0025] In the figure: 1, blade casting; 2, wall thickness detection section; 3, wall thickness detection point; 4, blade section profile; 5, measured wall thickness circle; 6, theoretical wall thickness circle; 7, inner cavity structure profile; 8, measured wall thickness circle connecting line; 9, theoretical wall thickness circle connecting line. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0027] A method for correcting the deviation and deformation of an engine blade ceramic core, comprising the following steps:

[0028] According to the wall thickness detection scheme of the blade casting 1 (as shown in Figure 1 , a plurality of wall thickness detection sections 2 are taken on the blade profile of the casting, and a plurality of wall thickness detection points 3 are designed at specified positions of each detection section, ultrasonic detection technology is used to measure all the wall thickness detection points 3, and the measured wall thickness values are recorded;

[0029] Through 3D modeling software, each wall thickness detection section 2 of the blade casting 1 model is analyzed, and the blade section profile 4 of the wall thickness detection section 2 is drawn, as shown in Figure 2 , the actual measured wall thickness values of the detection points are represented by a measured wall thickness circle 5 by using the tangent circle method, that is, a circle is drawn through the measured wall thickness detection points 3, and is tangent to the blade profile contour curve, the circle has a diameter of the measured wall thickness value, and similarly, the theoretical wall thickness size is also drawn according to the tangent circle method to draw a theoretical wall thickness circle 6, by comparing the measured wall thickness circle 5 and the theoretical wall thickness circle 6, the measured wall thickness size and the theoretical wall thickness size at the wall thickness detection point 3 can be clearly compared, so as to determine the deviation of the measured wall thickness size and the theoretical wall thickness size at the wall thickness detection point 3;

[0030] At this time, the inner cavity structure profile 7 of the blade section profile 4 is copied and extracted, and the lines of the inner cavity structure profile 7 are constrained as a glued whole, the three wall thickness detection points 3 with the largest deviation of the measured wall thickness circle 5 and the theoretical wall thickness circle 6 are selected, the glued inner cavity structure profile 7 is tangent to the three measured wall thickness circles 5 with the largest deviation, and the glued inner cavity structure profile 7 is fixed by the three constraints, as shown in Figure 3 .

[0031] At this time, the inner cavity structure profile 7 of the constraint fixation can be approximately the cross section profile of the actual ceramic core after eccentricity, the original inner cavity profile curve in the blade wall thickness detection section 2 and the extracted inner cavity structure profile 7 of the constraint fixation are compared, whether the ceramic core is deformed in the casting process can be analyzed, and the deformation trend and deformation amount are measured, specifically, by comparing the chord length angle and displacement size of the original inner cavity profile curve in the blade wall thickness detection section 2 and the extracted inner cavity structure profile 7 of the constraint fixation, the core deviation direction and core deviation displacement of the ceramic core in the wall thickness detection section 2 in the casting process are analyzed, and the specific core deviation size is measured, so that the quantitative analysis result is obtained;

[0032] After analyzing each wall thickness detection section 2, the overall size difference is planned and arranged, specifically, the measured wall thickness circle connecting line 8 corresponding to the longitudinal size and the theoretical wall thickness circle connecting line 9 are compared, as shown in the figure, the core deviation angle of the ceramic core in the longitudinal direction is measured, through process theory analysis, according to the measured core deviation angle and displacement size, the ceramic core model is deviated and moved according to the measured core deviation angle and displacement size, and the ceramic core model is moved to the position after the core deviation, the correction size of the support pin is measured, and the pin in the wax mold is adjusted, so that the anti-deformation parameter is designed and the mold is corrected, after correction, a new round of trial production analysis is carried out. Figure 4

[0033] The working principle of the present application is that the theoretical wall thickness value and the measured wall thickness value are compared by the circle cutting method, the measured ceramic core inner cavity profile is determined by the maximum wall thickness deviation of three places, the longitudinal core deviation angle of the ceramic core is measured by the corresponding measured wall thickness circle connecting line 8 of each wall thickness detection section 2, the actual position of the ceramic core in actual production is determined by deviation and movement, so that the correction value of the support pin is obtained by reverse analysis, compared with the traditional correction method, the deformation and core deviation of the ceramic core are quantified, the angle, displacement and direction are analyzed from multiple aspects, 3D modeling analysis and trial production ultrasonic wall thickness measurement are combined, and the size of the complex and precise inner cavity is corrected and controlled as a whole.

[0034] The present application is applied to the casting process of complex inner cavity high-precision blades, the measured wall thickness value in the trial production process is used for reverse analysis of the specific size and trend of the ceramic core deformation and core deviation by 3D modeling software, the correction value is quantified, the difficulty of analyzing the size of the inner cavity of the casting is reduced, the accurate control of the inner cavity size is realized, the precision of the casting is improved, and the trial production times of the casting are reduced; the thermal stress deformation and the core deviation problem of the ceramic core in the casting process of the complex cavity blade can be specifically quantitatively analyzed, computer theoretical calculation and analysis are adopted, and the research and development cost is greatly reduced.

[0035] The measured wall thickness connecting line of each wall thickness detection section 2 is analyzed, the longitudinal core deviation angle of the ceramic core is measured, the analysis of the core deviation of the ceramic core is not limited in one section, and the error caused by the longitudinal angle deviation is analyzed. ​

[0036] The present application combines the actual casting result measured by ultrasonic wave, combines the wall thickness value deviation and the correction value of the supporting pin by the deflection and movement of the ceramic core model, and has higher practical value of the correction result analyzed by the combination of practice and theory.

[0037] The above only describes some exemplary embodiments of the present application by way of illustration, and it is needless to say that the described embodiments can be modified in various ways without departing from the spirit and scope of the present application for those skilled in the art. Therefore, the above description is illustrative in nature and should not be understood as limiting the scope of protection of the claims of the present application.

Claims

1. A method for correcting eccentricity and deformation of a ceramic core for engine blades, characterized in that: Includes the following steps: S1. According to the blade casting wall thickness detection scheme, take several wall thickness detection sections on the blade shape of the casting, and design several wall thickness detection points at the designated positions of each detection section. Measure all wall thickness detection points and record the measured wall thickness values. S2. Analyze each wall thickness detection section of the blade casting model using 3D modeling software, create the blade section outline of the wall thickness detection section, and use the tangent circle method to represent the actual measured wall thickness value at the detection point as a measured wall thickness circle. At the same time, the theoretical wall thickness size is also drawn as a theoretical wall thickness circle according to the tangent circle method. Compare the measured wall thickness circle and the theoretical wall thickness circle to determine the deviation between the measured wall thickness size and the theoretical wall thickness size at the wall thickness detection point. S3. Copy and extract the inner cavity structure contour of the blade cross section contour, and constrain the lines of the inner cavity structure contour into a glued whole. Select the three wall thickness detection points with the largest deviation between the measured wall thickness circle and the theoretical wall thickness circle, and constrain the glued inner cavity structure contour tangent to the three measured wall thickness circles with the largest deviation. Fix the glued inner cavity structure contour through the three constraints. S4. By comparing the original inner cavity contour curve in the blade wall thickness detection section with the extracted and re-constrained inner cavity structure contour, we can analyze whether the ceramic core is deformed during the casting process and measure the deformation trend and amount. S5. After analyzing each wall thickness detection section, take into account the overall dimensional differences, design the anti-deformation parameters through process theory analysis, and correct the mold. After correction, conduct a new round of trial production analysis.

2. The method for correcting eccentricity and deformation of a ceramic core for engine blades according to claim 1, characterized in that: In step S4, by comparing the original inner cavity contour curve in the blade wall thickness detection section with the chord length angle and displacement dimension of the extracted and re-constrained inner cavity structure contour, the eccentric direction and eccentric displacement of the ceramic core in the wall thickness detection section during the casting process are analyzed, and the specific eccentric dimension is measured to quantify the analysis results.

3. The method for correcting eccentricity and deformation of a ceramic core for engine blades according to claim 1, characterized in that: In step S5, after analyzing each wall thickness detection section, the measured wall thickness circle corresponding to the longitudinal dimension is connected with the theoretical wall thickness circle and compared to measure the eccentricity angle of the ceramic core in the longitudinal direction.

4. The method for correcting eccentricity and deformation of a ceramic core for engine blades according to claim 3, characterized in that: In step S5, based on the measured eccentric angle and displacement, the ceramic core model is deflected and moved according to the measured eccentric angle and displacement, and moved to the position after eccentricity. The correction dimension of the support pin is measured, and the pin in the wax mold is adjusted.

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