CN-121988993-A - Forming method for bent blades of stamping and welding centrifugal pump

CN121988993ACN 121988993 ACN121988993 ACN 121988993ACN-121988993-A

Abstract

The invention discloses a method for forming bent blades of a stamping welding centrifugal pump, which relates to the field of centrifugal pump blades and comprises the steps of S1, three-dimensional modeling and plane unfolding, S2, wire cutting, S3, die forming, S4, three-dimensional scanning, S5, arc analysis, S6, contour analysis, S7, clamping adaptation, gap detection, S8 and forming quality verification. According to the invention, a stamping forming process and a three-dimensional scanning feedback technology system are combined to form a closed-loop precision control system, after stamping forming, a three-dimensional scanner is used for rapidly acquiring actual surface point cloud data of the blade, and the actual surface point cloud data is compared with a design model in high precision, so that profile deviation caused by rebound is accurately quantized. Based on the deviation data, a reverse compensation correction is performed on the mold profile. The problems of out-of-tolerance profile and welding assembly clearance caused by rebound are solved, and the manufacturing of the bent blade of the centrifugal pump with high precision, high efficiency and high consistency is realized.

Inventors

Jiang Xiongqiang
LUO WEICHAO
ZENG ZHI
ZHANG MANLING
JIANG BIN
YANG SHANGMING
LI XUEZHONG

Assignees

南方泵业股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260330

Claims (7)

1. The method for forming the bent blade of the stamping and welding centrifugal pump is characterized by comprising the following steps of: S1, three-dimensional modeling and plane expansion, namely carrying out hydraulic design on an impeller by using three-dimensional design software according to pump design requirements, generating a three-dimensional model of the blade, determining a rotating shaft of the impeller as a Z axis, and synchronously expanding the three-dimensional model of the blade into a two-dimensional plane contour map through a metal center line plane expansion function of the three-dimensional design software; S2, wire cutting, namely cutting a plane blank of the blade from the plate by adopting a wire cutting process based on the two-dimensional plane profile of the blade generated in the step S1; S3, mould forming, namely designing and manufacturing an upper stamping mould and a lower stamping mould which are matched with the three-dimensional model of the blade, wherein the curved surface of the mould cavity adopts reverse compensation design, firstly, simulating a stamping forming process by utilizing finite element analysis software according to the material, thickness and rebound empirical formula of a plate used by the blade, compensating the rebound quantity according to a simulation result, and then superposing the compensated rebound quantity on the curved surface of the theoretical blade, so as to generate a mould profile subjected to pre-compensation, and carrying out one-step stamping forming on the plane blank obtained in the step S2 by using the mould processed by the mould profile to obtain the primary forming blade with the three-dimensional space bending shape; S4, three-dimensional scanning, namely using a three-dimensional laser scanner to perform omnibearing scanning on the preformed blade obtained in the S3 to obtain real-time point cloud data of high density on the surface of the blade, importing the point cloud data into detection software, aligning and comparing the point cloud data with the three-dimensional model of the blade in the S1 under a unified coordinate system, calculating the deviation value of each measuring point and the corresponding point of the theoretical model through the best fitting alignment of the detection software, and automatically generating a contour deviation color thermodynamic diagram of the surface of the whole blade by using the detection software; S5, performing arc analysis, namely quantitatively analyzing the contour deviation color thermodynamic diagrams generated in the S4, extracting 5-10 key theoretical sections of the blade along the radial direction and the vertical Z axis of the blade, adjusting theoretical contour lines according to positive and negative deviation conditions of the theoretical sections in each contour deviation color thermodynamic diagram, generating target correction contours, summarizing correction information of all sections, reversely mapping the correction information to a three-dimensional space, identifying a critical area which is out of tolerance due to rebound, correcting a cavity curved surface of a stamping die according to deviation data, and re-stamping the rebound-compensated blade by adopting the corrected die; s6, contour analysis, namely correcting the welding surfaces of the front cover plate and the rear cover plate of the blade based on the contour deviation thermodynamic diagram generated in the S4, drawing a circle by taking 10-20 points on a theoretical line (2) as circle centers and the deviation obtained by the contour deviation thermodynamic diagram as a radius, wherein a fitted curve is a cover plate correction line (1), correcting the initially formed blade by adopting processes such as linear cutting and the like, and gradually enabling the contour of the blade to coincide with the contour of the theoretical model until the profile precision meets the design requirement; And S7, clamping adaptation and gap detection, namely after the profile precision of the blade reaches the standard, entering a pre-assembly stage, fitting the blade corrected in the S6 with the front cover plate and the rear cover plate, detecting the local gap of the welding surface of the blade and the cover plate by adopting a clearance gauge or a gap gauge, returning to the S6 for fine adjustment of the profile if the gap is out of tolerance, and welding the blade with the front cover plate and the rear cover plate into a complete impeller part by adopting a laser welding process after the gaps of all the matching surfaces are controlled within the allowable range of the laser welding process.
2. The method for forming the bent blade of the stamping and welding centrifugal pump according to claim 1, wherein in the step S1, the three-dimensional design software is Solidworks or UG software, and the two-dimensional plane profile of the blade is used as a basis for linear cutting in the step S2, so that the outer contour dimension of the blade in a plane state is ensured to be consistent with the height in the two-dimensional plane profile.
3. The method for forming curved blades of press-welded centrifugal pump according to claim 1, wherein in step S3, a rebound empirical formula is adopted, wherein the rebound angle of the male die is Arc radius of male die Wherein R is the radius of a theoretical blade arc, sigma s is the yield limit of a material used for the blade, E is the elastic modulus of the material used for the blade, delta is the thickness of the blade, alpha is the rebound angle of the blade, and AUTOformR is adopted by the finite element analysis software.
4. The method of claim 1, wherein in step S4, the detection software is Geomagic Control.
5. The method of claim 1, wherein in the step S6, the point is encrypted at a position with a larger radian, the tangent line of each circle is used as a cover plate correction line (1), the positive deviation is rounded near the side tangent point of the blade, and the negative deviation is rounded far from the side tangent point of the blade.
6. The method for forming curved blades of a press-welded centrifugal pump according to claim 1, wherein in step S7, the clearance between the allowable mating surfaces of the laser welding process is within 1mm, and the power and speed of the laser welding process are adjusted according to the actual working conditions.
7. The method of forming a bent vane of a press welded centrifugal pump of claim 1, further comprising: And S8, verifying the molding quality, namely after the welding procedure of S7 is finished, carrying out stress relief annealing treatment on the welded and molded impeller, scanning the annealed impeller by adopting a three-dimensional laser scanner again, finally comparing the three-dimensional molded surface of the final finished product with an original theoretical model to generate a final detection report, evaluating whether the hydraulic performance of the impeller meets the standard, and finishing closed-loop verification of the molding quality.

Description

Forming method for bent blades of stamping and welding centrifugal pump Technical Field The invention relates to the field of centrifugal pump blades, in particular to a method for forming bent blades of a stamping and welding centrifugal pump. Background Centrifugal pumps are widely used because of their simple structure and stable flow. The impeller which is welded and assembled after being formed by stamping has the advantages of high production efficiency and relatively low cost, and is particularly suitable for small and medium-sized pumps and batch production. However, the material springback problem inherent to the stamping process results in unpredictable deviations in the molded curved blade profile from the design model. The deviation not only affects the molded line precision of a single blade, but also causes poor consistency among a plurality of blades, and further generates accumulated errors when the blades are welded and assembled with the front cover plate and the rear cover plate, and assembly gaps or interference occur. The traditional solution is mainly to rely on the experience of technical workers to manually grind or adjust the die, has low efficiency and unstable quality, and is difficult to meet the high-end application scene with increasingly severe requirements on pump efficiency, vibration and cavitation performance. Chinese patent document (CN 119879808 a) provides a blade profile scanning method based on measured profile normal correction. According to the technical scheme, actual measurement data are obtained through scanning along a triangular waveform, so that the normal line of each point on the actual blade profile is approximately calculated, the problem that a traditional constant section method is used for measuring the blade profile to generate a larger cosine error when the deviation between a real object and a model is larger is solved, the measurement accuracy of the blade profile is improved, however, the technical scheme is focused on a scanning path, and the complete flow of blade forming is not described. Chinese patent document (CN 105945533 a) provides a method for shaping centrifugal fan blades. The method comprises the steps of dividing a long blade into an inlet section and an outlet section according to molded lines, designing the shape and the size of the outlet section to be consistent with those of a short blade, respectively adopting a first die to press the inlet section of the long blade, adopting a second die to press the outlet section of the short blade and the outlet section of the long blade simultaneously, and finally welding and splicing the two parts of the long blade to form the long blade, thereby realizing high-precision manufacturing of the blade with lower die cost. However, according to the technical scheme, the blade is manufactured only through a die stamping forming method, errors brought in the actual manufacturing process are ignored, and the precision of the blade cannot be completely guaranteed. Therefore, there is a need for a systematic molding method that can quantitatively control springback, achieve precise correction, and ensure final welding assembly accuracy. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a method for forming bent blades of a stamping and welding centrifugal pump, which solves the problems of poor profile precision caused by material rebound, gaps between the blades and front and rear cover plates during welding and clamping, and poor welding quality. The invention aims to achieve the following technical scheme that the method for forming the bent blade of the stamping and welding centrifugal pump comprises the following steps of: S1, three-dimensional modeling and plane expansion, namely carrying out hydraulic design on an impeller by using three-dimensional design software according to pump design requirements, generating a three-dimensional model of the blade, determining a rotating shaft of the impeller as a Z axis, and synchronously expanding the three-dimensional model of the blade into a two-dimensional plane contour map through a metal center line plane expansion function of the three-dimensional design software; S2, wire cutting, namely cutting a plane blank of the blade from the plate by adopting a wire cutting process based on the two-dimensional plane profile of the blade generated in the step S1; S3, mould forming, namely designing and manufacturing an upper stamping mould and a lower stamping mould which are matched with the three-dimensional model of the blade, wherein the curved surface of the mould cavity adopts reverse compensation design, firstly, simulating a stamping forming process by utilizing finite element analysis software according to the material, thickness and rebound empirical formula of a plate used by the blade, compensating the rebound quantity according to a simulation result, and then superposing the compensated rebound