Abstract
The origin of the lost-wax method in China has always been a focus of attention for scholars both domestically and internationally, yet no consensus has been reached in existing research. This article reviews the technological and historical conditions surrounding the origin of the lost-wax method in ancient China, as well as the main arguments in academic debates. By utilizing simulation experiments in the investment casting process, it effectively documents the wax pattern and mold shell production. Starting from various process details such as wax materials, slurries, folds, mud cores, core supports, and demolding, this article aims to fill the gaps in the study of the lost-wax method from the perspective of using modern techniques to verify ancient methods. It also sheds light on the difficulties in the development of the mold-losing principle.
| Key Words | Description |
|---|---|
| Lost-Wax Method | An ancient casting technique involving the creation of a wax model, coating it with a mold shell, and melting away the wax to cast the final product. |
| Investment Casting | A modern casting process similar to the lost-wax method, characterized by the use of wax patterns, mold shells, and molten metal casting. |
| Mold-Losing Principle | The principle of removing the mold (in this case, the wax pattern) to create a hollow cavity for metal casting. |
1. Introduction
The academic community has conducted extensive research on the origin, transmission process, and mechanisms of Chinese ancient metallurgical technology. However, there is still a lack of in-depth study on the similarities and differences of metallurgical handicrafts in the pre-Qin period, as well as the relationship between metallurgical techniques and regional civilization development. The lost-wax method, as one such technique, has also attracted numerous scholars who have proposed different technological pathways to explore its origins.
2. Overview of Debates and Views on the Lost-Wax Method
| Period | Research Focus | Key Arguments |
|---|---|---|
| Before 1931 | Initial research on lost-wax method | Foreign scholars mostly held the view of lost-wax casting due to the unearthing of numerous exquisite bronze artifacts. |
| 1931-1959 | Combined lost-wax and block-mold method | With the discovery of numerous pottery mold artifacts and Chinese scholars’ demonstration of bronze casting techniques, doubts arose about the pure lost-wax method, leading to the adoption of a combined lost-wax and block-mold method. |
| 1960-1977 | Focus on block-mold method | |
| 1978-2018 | Debate between block-mold and lost-wax methods | |
| 2019-Present | Detailed comparison of lost-wax casting techniques for hollow artifacts | New research ideas emerged, and the study of the lost-wax method began to expand to hollow artifacts, exploring the realization of the mold-losing principle in ancient China. |
3. Verification of the Lost-Wax Method through Investment Casting Process
3.1 Process Record and Analysis of Investment Casting
Investment casting can be divided into five major parts: wax pattern production, mold shell production, pouring, post-processing, and inspection. This section focuses on the wax pattern and mold shell production, which are the most critical and time-consuming steps.
3.1.1 Wax Pattern Production
| Step | Description | Illustrations |
|---|---|---|
| Wax Treatment | Mixing new and old wax materials in a ratio of 1:9, heating to 90°C, and filtering impurities. | <img src=”https://example.com/wax_treatment.jpg” /> (Illustration placeholder) |
| Wax Injection | Injecting treated wax into molds under pressure, spraying release agent, and cooling to form wax patterns. | <img src=”https://example.com/wax_injection_and_demolding.jpg” /> (Illustration placeholder) |
| Wax Repair | Inspecting and repairing wax patterns, including removing flash, flow lines, bubbles, and other defects. | <img src=”https://example.com/wax_repair.jpg” /> (Illustration placeholder) |
| Tree Assembly | Arranging wax patterns in a certain number and welding them to a tree for easy handling during pouring. | <img src=”https://example.com/tree_assembly.jpg” /> (Illustration placeholder) |
3.1.2 Mold Shell Production
| Step | Description | Illustrations |
|---|---|---|
| Cleaning | Removing wax residue and contaminants from wax patterns to ensure surface quality. | <img src=”https://example.com/cleaning.jpg” /> (Illustration placeholder) |
| Facing Coat | Dipping wax patterns into a zirconium slurry and covering with zirconium sand, then drying. | <img src=”https://example.com/facing_coat.jpg” /> (Illustration placeholder) |
| Backing Coat | Applying additional layers of zirconium slurry and sand, gradually increasing sand size. | <img src=”https://example.com/backing_coat.jpg” /> (Illustration placeholder) |
| Dewaxing | Removing wax patterns from the mold shell using high-temperature steam. | <img src=”https://example.com/dewaxing.jpg” /> (Illustration placeholder) |
| Shell Repair and Packing | Repairing any defects in the mold shell and packing thick areas with cotton to ensure sequential solidification during pouring. | <img src=”https://example.com/shell_repair_and_packing.jpg” /> (Illustration placeholder) |
| Firing | Heating the mold shell to 1050°C to burn out any remaining wax and strengthen the shell. | <img src=”https://example.com/firing.jpg” /> (Illustration placeholder) |
4. Discussion
The investment casting process, with its detailed documentation and modern technology, provides a valuable tool for verifying the lost-wax method. By comparing the processes and techniques used in both methods, we can gain deeper insights into the origins and evolution of the lost-wax method in ancient China.
5. Conclusion
The study of the lost-wax method through the lens of investment casting reveals the intricate details and technological advancements that have shaped this ancient casting technique. By leveraging modern technology and simulating ancient processes, we can better understand the challenges and innovations faced by ancient craftsmen, and appreciate the lasting legacy of the lost-wax method in the history of metallurgy.