For a long time, mold making has been a cornerstone of American manufacturing. In recent decades, this traditional craft has evolved significantly, from using hand-filed steel to remove excess material, to relying on modern gas-fired furnaces for heat treatment of steel, and employing computerized processes to achieve perfect product quality and top-notch production efficiency. 21st-century tools and molds can be broadly categorized into two types: traditional and innovative. Each type can be determined based on its industrial applications. Traditional mold makers belong to the older generation of tool and mold manufacturers who focus primarily on the application of manual techniques to complete their mold-making work. Innovative mold makers belong to the new generation of tool and mold manufacturers who focus primarily on the transformation of overall processes and rely on equipment and software to complete tasks. Now, the American mold industry is open to the global market, making competition in this traditional business even more brutal and intense. The only major threat facing the tool and mold industry is the obstruction of innovative change. Developing businesses also include adding automated equipment, increasing programming software, improving assembly line processes, and introducing new technologies. Complementary Technology to EDM Waterjet cutting technology is a complementary technology to EDM and is increasingly accepted. For mold manufacturers, the processing speed of waterjet cutting machines is ideal, suitable for roughing production before EDM finishing and for cutting bulk materials, thus reducing production time. In the mold manufacturing industry, EDM is a very common processing method. It is applied to the cutting of workpiece materials, such as machining blind holes and mold cavities. EDM uses fuzzy logic technology, which can adapt to various minute changes in processing conditions, enabling workpieces to achieve micron-level surface quality. EDM processing technology has greatly improved the level of mold products, including product precision, quality, output, and profit. In mold manufacturing processes, ram-type EDM machines and EDM mold processing machines are commonly used. This non-contact processing method, combined with low-pressure flushing, can process very thin and high-precision parts. A recent study compared the cutting speed of EDM wire cutting machines with that of waterjet cutting technology when machining 1-inch (1in = 25.4mm) thick steel workpieces. The experimental cutting on the EDM machine used a 0.012-inch diameter cutting wire, and the cutting speed was 0.25 in/min. Experimental cutting using a waterjet cutting machine showed a cutting speed of 2.9 in/min, more than 10 times higher than the EDM cutting speed. 1. Theoretical Basis Waterjet cutting utilizes a high-pressure water jet with diamond abrasive added to it, which is then sprayed at high speed onto the workpiece to remove excess material. No heat is generated during waterjet cutting, thus eliminating the risk of material deformation. Since the removed excess material is in block form rather than chips, material is saved, and the removed material can have other uses. Roughing with a ram-type EDM or EDM wire cutting machine creates a heat-affected zone (HAZ), where the material generates high heat but does not melt. This HAZ alters the material's properties. Therefore, roughing with a ram-type EDM machine easily generates high-energy heat, increasing the risk of thermal deformation and affecting the final quality of the workpiece. During waterjet cutting, the precision of the water flow changes as it is ejected from the nozzle's orifice, affecting the flatness and surface quality of the workpiece. Because waterjet cutting is quite fast, it cannot guarantee that the machined edges will meet the precision and tolerances of an EDM machine. For this reason, these two technologies are considered complementary. 2. Benefits to the Mold Manufacturing Industry Especially for mold manufacturers, waterjet cutting is the best complement to EDM for workpieces that require less time and precision. For workpieces with high tolerance and precision requirements, EDM machines should be used. The application scope of waterjet cutting extends far beyond its basic known applications, bringing speed and flexibility to EDM. Another study on a 1-inch thick, 2-inch diameter part showed that roughing with waterjet cutting saved 28% of the time compared to using an EDM machine (see Table 2). 3. Diversified Production Functions For the mold industry, the diversification of waterjet cutting technology is no less important than its processing speed. In the United States, a company's production business is not guaranteed, largely depending on whether its domestic mold manufacturers can develop special processes or adopt specialized technologies that help them survive. Waterjet cutting technology can allow mold manufacturers to separate themselves from a narrow market and further expand their customer base. EDM (Electrical Discharge Machining) is a specialized processing technology. It uses electrical discharge machining to cut workpieces, but it is only suitable for processing conductive materials, such as graphite and metals. Waterjet cutting machines, on the other hand, are universal cutting systems. They can cut a wide range of materials, such as glass, ceramics, wood, stone, plastics, and rubber. Parts processed using waterjet cutting technology have very smooth and bright edges, without serrations, metal slag, or burrs, eliminating the need for grinding or other finishing. Waterjet cutting does not require tool changes or workpiece repositioning, saving related time and costs. For parts that do not require further processing on EDM machines in terms of dimensional tolerances, waterjet cutting often requires less than 10% of the EDM processing time. When purchasing new equipment, one of the first considerations should be its ROI. For waterjet cutting technology, the average cost per inch of cutting decreases as speed increases. Therefore, the machine tool can only achieve its highest performance and profit margin under optimal cutting speed conditions. When the machine tool operates at its highest power and fastest possible speed, the overall costs associated with cutting (including abrasives, power, water supply, and filters) will be minimized. The application of waterjet cutting technology in mold processing workshops is primarily driven by its cost, manifesting in increased output and production capacity. Mold manufacturers must constantly seek new processing methods to further improve their production efficiency and capabilities. Applying new technologies like waterjet cutting not only further enhances the efficiency of mold manufacturers but also stimulates new opportunities and opens doors to new markets due to its diversified production capabilities.