Dimensional variation stream modeling of investment casting process based on state space method

Proceedings of the Institution of Mechanical Engineers, Part B:

Cui

et al. 2023

Due to variable cross-sections and a thin-walled structure, gas turbine blades have stringent dimensional, and geometrical tolerance requirements. Single-crystal hollow blades are manufactured using the following investment casting processes: ceramic core preparation, wax injection, ceramic coating, wax removal, metal casting, and finishing. The main causes of the final casting deformation are wax pattern deformation, core deflection, and metal solidification warpage. This paper proposes a numerical simulation method to predict the deformation of the wax pattern, core deflection, and the directional solidification (DS) process of large single-crystal blades. Additionally, it investigates the displacement field and the influence of casting process parameters on dimensional accuracy. Three groups of DS process parameters were selected for experiments, and the deformation prediction was in agreement with the experimental results. The selected blade section deformation is the smallest when the pouring temperature is 1530°C and the withdrawal rate is 5 mm/min. The proposed finite element model is efficient to predict the deformation in all the investment casting processes, providing geometric guidance for the control of the dimensional accuracy of the turbine blade.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling and experimental study on deformation prediction of thin-walled turbine blades during investment casting process

Zhou

Proceedings of the Institution of Mechanical Engineers, Part B:

Cui

et al. 2023

“…Investment casting is an important industry expertise and has been widely used in various manufacturing fields due to its advantages of high precision, high shape complexity, and good adaptability to various alloys. [1][2][3] Singh and Singh 4 reviewed the development of this technique and demonstrated that the main steps of investment casting include wax mold pressing and assembly, mold preparation, dewaxing and mold baking, liquid metal pouring, mold cleaning and posttreatment of castings.…”

Section: Introductionmentioning

confidence: 99%

Comparison of various gating systems for investment casting of hydraulic retarder impeller with complex geometry

Proceedings of the Institution of Mechanical Engineers, Part B:

et al. 2020

Due to the complex structure and thin thickness of the guide vane edge of the hydraulic retarder impeller, the casting defects such as shrinkage porosity and misrun are usually formed during casting, which have a close relationship with the filling and solidification process. In this work, the filling and solidification processes of impeller in various gating systems, named case 1 to 3, were simulated and the distribution characteristics of potential shrinkage porosity defects were predicted by ProCAST software based on the mathematical models, boundary conditions, and parameters of investment casting. The simulation results show that the aim of complete filling of the impeller can be achieved by using all of the three gating systems. However, only the case 3 gating system consisted with one sprue riser and four feeding risers can provide the impeller with suitable feeding channel in melt solidification process. Therefore, no predicted shrinkage porosities form in the impeller because the defects can transfer to the gating system during solidification. The optimized gating system have been verified by experiment, and the rapid casting of the impeller has been realized by using 3D printed polystyrene patterns. The results of visual and X-ray inspections show that both the misrun and shrinkage porosity defects were eliminated in the actually final cast, which matched well with the numerical simulation results for the investment casting of the impeller. Many experiment results of the new product show that these optimization gating system are very helpful to reduce the casting defect and to improve the product quality.

“…Among the models of multistation assembly variation propagation, the state space method 16,17 and stream of variation methodology 18 are explored in much greater depth due to their linear structure and the automatic handling of complicated stage-wise interaction. In aircraft assembly process, assembly variation is affected not only by positioning, clamping, 19 joining 2,3,13,20 and so on, but also by part distortion in manufacture.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, the focus of variation analysis of the multi-station hierarchical assembly processes is the establishment of the relationship between the tolerances of process elements across multiple stages and the variation of the final product. Among the models of multi-station assembly variation propagation, the state space method 16,17 and stream of variation methodology 18 are explored in much greater depth due to their linear structure and the automatic handling of complicated stage-wise interaction. In aircraft assembly process, assembly variation is affected not only by positioning, clamping, 19 joining 2,3,13,20 and so on, but also by part distortion in manufacture.…”

Section: Introductionmentioning

confidence: 99%

Positioning variation modeling for aircraft panels assembly based on elastic deformation theory

Proceedings of the Institution of Mechanical Engineers, Part B:

Hou

et al. 2017

Dimensional variation in aircraft panel assembly is one of the most critical issues that affect the aerodynamic performance of aircraft, due to elastic deformation of parts during the positioning and clamping process. This article proposes an assembly deformation prediction model and a variation propagation model to predict the assembly variation of aircraft panels, and it derives consecutive three-dimensional deformation expressions which explicitly describe the nonlinear behavior of physical interaction occurring in compliant components assembly. An assembly deformation prediction model is derived from equations of statics of elastic beam to calculate the elastic deformation of panel component resulted from positioning error and clamping force. A variation propagation model is used to describe the relationship between local variations and overall assembly variations. Assembly variations of aircraft panels due to positioning error are obtained by solving differential equations of statics and operating spatial transformations of the coordinate. The calculated results show a good prediction of variation in the experiment. The proposed method provides a better understanding of the panel assembly process and creates an analytical foundation for further work on variation control and tolerance optimization.