Abstract
With the vigorous development of China’s manufacturing industry, the technology of the manufacturing industry is constantly improving. The manufacturing industry is known as the “mother of industry”. Casting equipment is crucial to product performance, quality, stability, and durability. Therefore, casting plays a vital role. This paper elaborates on the process characteristics and effectiveness comparison between lost foam casting and sand casting.
1. Introduction
Lost foam casting and sand casting are two major processes in the current foundry industry, each with its advantages and disadvantages. With the rapid development of manufacturing technology today, there is a need to improve these two processes, enhancing their strengths and mitigating their weaknesses, so that they can each make their respective contributions to the foundry industry.
2. Lost Foam Casting Process, Effectiveness, and Prospects
Table 1: Overview of Lost Foam Casting Process
| Characteristics | Description |
|---|---|
| Process Name | Lost Foam Casting (Also known as Full-Mold Casting, Vaporizable Pattern Casting) |
| Inventor | Slower (USA), patented in 1958 |
| Initial Use | Production of arts and crafts castings |
| Key Characteristics | Uses unbonded dry sand for molding, high-frequency low-amplitude vibration for compaction, no need to remove the pattern after molding. Pouring causes the foam plastic to gasify and decompose, replaced by molten metal. |
Table 2: Effectiveness Features of Lost Foam Casting
| Effectiveness | Description |
|---|---|
| Complexity of Castings | Can produce complex castings that are difficult to make with traditional casting methods. |
| Dimensional Accuracy and Surface Finish | Directly proportional to the manufacturing accuracy of the foam plastic part, approaching the stability of investment casting. |
| Process Simplification | Eliminates the need for sand cores, mold parting, mold assembly, sand mixing, and simplifies sand removal. |
| Elimination of Defects | Effectively eliminates casting defects caused by water, binders, and additives. |
| Automation and Mechanization | Easy to achieve automation and mechanization in production. |
| Cost Savings | Old sand recovery rate exceeds 90%, energy cost savings of about 15%, and casting cost reduction of about 30%. |
Research Directions for Lost Foam Casting
Table 3: Research Directions
| Direction | Description |
|---|---|
| Pattern Material and Manufacturing Technology | Development of high-quality pattern materials with low gas generation, low density, and sufficient strength to resist deformation. |
| New Casting Materials | Research on high-quality coatings with high strength and good gas permeability. |
| Dry Sand Research | Enhancement of dry sand vibration technology to facilitate automation and mechanization. |
3. Sand Casting Process and Effectiveness
Table 4: Overview of Sand Casting Process
| Process Steps | Description |
|---|---|
| Molding | Preparation of sand molds. |
| Core Making | Preparation of sand cores. |
| Drying | Drying of sand molds and cores. |
| Mold Assembly | Assembly of sand molds and cores. |
| Pouring | Pouring molten metal into the mold. |
| Sand Removal | Removal of sand from the casting. |
| Cleaning | Final cleaning of the casting. |
Table 5: Effectiveness Features of Sand Casting
| Effectiveness | Description |
|---|---|
| Material Versatility | Wide range of mold material options, long service life, and low cost. |
| Dimensional Accuracy | Less stable due to cumulative errors in complex castings made with multiple molds. |
| Surface Finish | Rough surface due to the inherent roughness of sand molds. |
| Casting Defects | Most defects arise from poor mold quality, such as uneven or tilted mold surfaces, installation deviations, and improper pouring systems. |
Prospects for Sand Casting
With the development of the foundry industry, high-compaction molding methods (including high-pressure molding, shot-pressure molding, and air-impulse molding) will be widely used. These methods reduce damage and deformation during mold transportation, assembly, and pouring, resulting in higher dimensional accuracy and surface quality of castings. However, the issue of sand mold rebound requires further investigation.
4. Conclusion
This paper has provided a detailed analysis of the process characteristics and effectiveness of both lost foam casting and sand casting. While sand casting offers versatility in mold material selection and long service life, lost foam casting excels in producing complex castings with high dimensional accuracy and surface finish. Both processes have their unique advantages and areas of application in the foundry industry. Further research and development are needed to enhance the quality and efficiency of these casting processes.