Abstract
This paper focuses on the topology design, structural analysis, and casting process analysis (CACE, Computer Aided Casting Engineering) of parts produced through rapid investment casting. The aim is to explore an integrated CAD/CAE/CACE methodology for rapid investment casting parts.
Keywords: Rapid Investment Casting, 3D Printing, Topology Design, Topology Optimization, Lattice Structure
1. Introduction
Rapid investment casting is an indirect additive manufacturing process for metal parts, offering advantages such as mature technology, low cost, material versatility, large-scale manufacturing, and no need for support removal. This paper aims to study the topology design and analysis for rapid investment castingC, including CAD modeling, CAE analysis, and CACE.
2. Literature Review
| Area | Research Status |
|---|---|
| 3DP and Investment Casting | Growing interest in combining 3D printing with investment casting |
| Topology Design | Topology optimization and lattice topology design are key methods |
| Rapid Investment Casting Process | Mature process with potential for further optimization |
3. Topology Design Techniques
Topology design involves removing internal redundant material that does not bear stress or affect performance, leading to improved mechanical properties. It includes topology optimization design and lattice topology design.
3.1 Topology Optimization Design
- Objective Function: Minimize structural compliance (maximize stiffness)
- Design Variables: Density of each element in the design area
- Constraint: Upper limit on the percentage of retained structural volume
3.2 Lattice Topology Design
- Involves filling non-critical load-bearing areas of traditional solid parts with lattices to achieve lightweighting or improved thermodynamic and vibration performance.
4. Integrated Topology Design Methodology for Rapid Investment Casting
| Step | Description |
|---|---|
| Topology Optimization | Use software to optimize the structure based on design requirements |
| STL Grid Generation | Convert the optimized result into STL grid format |
| Reverse Engineering | Improve grid quality through fitting and smoothing |
| Feature Curve Extraction | Extract feature curves from the STL grid for CAD design |
| CAD Design and Analysis | Use the feature curves to create a new CAD model and analyze it |
Case Study: Bearing Bracket for an Aircraft
- Characteristics: Complex topology, minimum thickness of 0.5mm, stainless steel material, and three-dimensional curve features.
- Topology Optimization Results: Density cloud map and STL grid model generated.
- CAD Design: Feature curves extracted and used to create a new CAD model.
5. Casting Process Analysis (CACE)
5.1 Introduction
The quality of rapid investment casting parts is closely related to the investment casting process, highlighting the importance of casting process design and selection.
5.2 Simulation Tools
- ProCAST: A professional CAE system used for simulating, evaluating, and optimizing casting products and processes.
5.3 Case Study: Bearing Bracket and Pyramid Lattice Sandwich Structure
- Simulation Results: Filling and solidification processes were simulated, and shrinkage was predicted.
- Optimization: Optimized casting process parameters through single-factor multi-level experiments and orthogonal tests.
6. Experimental Validation
6.1 3D Printing Experiment
- Equipment: Flashforge 3D Printer
- Material: PLA
- Parts: Engine bracket and bearing bracket
- Results: Preliminary analysis of the printability of the topological designs.
6.2 Casting Experiment
- Parameters: Pouring temperature, shell preheating temperature, and pouring speed optimized.
- Results: Defect prediction and quality evaluation through ProCAST.
7. Conclusion
This paper presents an integrated CAD/CAE/CACE methodology for rapid investment casting parts, demonstrating its effectiveness through case studies. The proposed methodology improves the efficiency of topological design and casting process optimization for rapid investment casting parts.