Rapid Prototyping (RP) technology, based on the principle of discrete layering, allows for the creation of prototypes or products by adding material in a layer-by-layer fashion. The concept of “growth” as a manufacturing technique can be traced back to the field of geomorphology, even dating back to the 19th century. Over time, RP technology has evolved into a critical innovation across various industries, including automotive, aerospace, and manufacturing.

1. Origins of Rapid Prototyping Technology

The roots of RP technology stretch back to 1892, when Blanther proposed a layered approach for making topographical maps in his U.S. patent. His method involved embossing contour lines onto a series of wax sheets, cutting along the contours, and stacking the sheets to create a 3D topographic map. In 1940, Perera developed a similar process, where cardboard was stacked after being cut along contour lines to form a 3D model of terrain.

In 1964, Zang further refined the method by recommending the use of transparent cardboard, each layer marked with detailed topographical features. These early developments laid the groundwork for the more advanced methods that would follow in the rapid prototyping field.

2. The Introduction of Photopolymerization

The breakthrough in RP technology came in 1972 when Matsubara proposed the use of photopolymer materials for layering. He suggested applying photosensitive resin onto fire-resistant particles (such as graphite powder or sand) and using selective light exposure to harden specific areas. Unhardened portions could be dissolved using a solvent, creating thin layers that were stacked to form a three-dimensional model.

In 1976, DiMatteo highlighted the capability of this technique to manufacture complex surfaces that would be difficult to machine using conventional methods, such as propellers, three-dimensional cams, and cavity molds. By the late 1970s, laser-based photopolymerization processes were introduced, further revolutionizing RP technology.

3. Commercialization of RP Technology

In 1977, Swainson patented a method for directly creating plastic models through selective laser exposure of 3D photopolymer objects. At the same time, Battelle Labs conducted similar work, leading to the commercialization of RP equipment. By 1979, Professor Nakagawa at the University of Tokyo was applying the layered method to create practical tools such as stamping dies, molding dies, and injection molds, including the development of complex cooling channels within injection molds.

1981 saw a major step forward with Hideo Kodama’s proposal for a functional photopolymer rapid prototyping system. Kodama introduced three different methods for layer formation:

1. Using a filter to control the UV light exposure and immersing the model in photopolymer resin.
2. Moving the model upwards through the resin to form new layers.
3. Combining methods from the first two, using optical fibers to selectively expose and harden the resin.

The 1980s also saw numerous other patents and innovations in RP technology. Notably, in 1988, 3D Systems introduced the SLA-250 photopolymer system, which was delivered to three users, marking the official commercialization of rapid prototyping devices.

4. The Global Spread of RP Technology

The United States led the way in the commercialization and development of RP systems. American companies such as 3D Systems, Stratasys, and DTM pioneered RP systems in the global market, with various methods such as SLA, FDM, and SLS. In contrast, Japan and European countries also followed suit, with companies like EOS in Germany, Cubital in Israel, and CMET in Japan contributing to the expansion of RP technology.

In the 1990s, China began its own research into rapid prototyping, with universities and research institutions such as Tsinghua University, Huazhong University of Science and Technology, and Xi’an Jiaotong University receiving government support for RP technology development. By the mid-1990s, these institutions began to release their own representative RP devices.

5. The Rise of Domestic RP Equipment in China

Over the past few decades, Chinese institutions and companies have continuously improved and innovated RP technology. Today, key technologies in photopolymer-based RP devices, powder sintering, and laminated object manufacturing have reached international standards. Due to the significantly lower costs of domestically developed RP systems compared to international equivalents, Chinese manufacturers have experienced reduced financial pressure when purchasing rapid prototyping equipment. This has led to increased market share for domestic RP equipment, facilitating the wider adoption of this technology in China.

As the field continues to evolve, RP technology is expected to further transform industries by improving efficiency, reducing production costs, and enabling more complex designs. The future of rapid prototyping looks bright, with new materials and methods on the horizon that will continue to push the boundaries of what is possible in manufacturing.