Mold is known as the “mother of industry”, its application can be traced back to ancient times. In the past few decades, as the wheel of the technological revolution rolled forward, the mold manufacturing industry opened a new chapter, and the technology has advanced by leaps and bounds, for the processing manufacturing industry has made a huge contribution. Nowadays, although the traditional manufacturing industry around the world is still the mainstay of production with molds, the development of molds is subject to the impact of 3D printing technology.
In recent years, with the development of Industry 4.0, China’s manufacturing industry is developing faster and faster from “manufacturing” to “intelligent manufacturing”. 3D printing technology has been widely used in China’s manufacturing industry. 3D printers can provide mold design and manufacture highly efficient, low-cost support. Even with the rapid development of 3D printing technology, in some areas, has gradually begun to subvert the mold technology and the formation of direct competition.
It is understood that compared to 3D printing technology, traditional mold manufacturing requires more steps and processes, and the mold production cycle is longer. When a mold manufacturer launches a new product, the new product needs to pass stringent international standards and certifications before it is launched, and the certification of numerous components will be time-consuming. This can put the new product at a significant disadvantage in terms of time to capture the market. 3D printing injection mold, on the other hand, is an efficient solution. Well-known manufacturer Schneider Electric did so, using 3D printing technology to manufacture injection molds in their open lab.
Whereas it normally takes weeks to two months to produce a mold, using 3D printing technology allows the mold to be prototyped in a matter of hours, and changes can be made immediately based on test results. Then the final product samples are molded. These product samples can be sent directly for certification, while traditional mold manufacturing may still be in production, and the finished 3D printed product can be certified even before the mold is finalized, significantly shortening the development cycle.
Only in the mold production cycle, 3D printing technology has produced a certain impact on traditional mold manufacturing. However, industry experts say that although 3D printing technology has many advantages such as short production cycle, convenient raw materials, and uniform product pressure, 3D printing technology can not completely replace the traditional mold manufacturing methods, this is because 3D printing technology in the production and manufacturing process there are still some problems.
For example, 3D printing technology is layer by layer processing to get the product, which will shorten the production cycle of the mold, but at the same time will also lead to the mold surface with step pattern effect. A similar problem exists with directly printed molds, which later require machining or sandblasting to eliminate these fine, toothy edges. Besides, holes smaller than 1mm must be drilled, larger holes need to be reamed or drilled, and threaded features need to be tapped or milled; these secondary processes largely undermine the speed advantage of 3D printing molds.
At the same time, injection molds need to be heated to very high temperatures to ensure good material flow properties. Aluminum and steel molds typically experience temperatures of 500F (260°C) and higher, especially when processing high-temperature plastics such as PEEK and PEI materials. It is easy to produce a few thousand parts with metal molds, and they can also be used as transition molds until the final mass production molds come out. The materials used to make molds using 3D printing technology are generally photosensitive or thermosetting resins, which are cured by UV light or laser. These plastic molds, although relatively hard, break down very quickly under the thermal cycling conditions of injection molding. 3D printed molds typically fail within 100 uses in mild environments with high-temperature plastics such as polyethylene and or styrene. For glass-filled polycarbonate and high-temperature resistant plastics, only a few parts can even be produced.
Also, a major reason for using 3D printing molds is their low cost. Production-grade machined molds typically cost $20,000 or more, meaning that a $1,000 printed mold is a like-for-like comparison. But this analogy is not fair, as the evaluation of printed molds typically only takes into account material consumption, and not labor, assembly and mounting, injection systems, and hardware. For example, ProtoLabsd’s aluminum molds cost $1500 to produce. If more parts need to be produced, using 3D printed molds, new molds would need to be reprinted and assembled machine tested for every 50-100 products produced. On the other hand, not considering the plastic used, aluminum molds typically still serve well after 10,000 parts are produced. Therefore, 3D printing is no more cost-effective than traditional mold-making methods when it comes to production costs.
Besides, in terms of product design, the principles and practices of traditional injection mold manufacturing have been around for more than a century, and the industry has studied them more thoroughly, for example, the draw angle must be greater than or equal to 5 degrees to meet most aluminum mold requirements. 3D printed mold injection molded plastic parts, however, face challenges and require extra care in the number and mounting position of plastic mold ejectors. 3D printed molds (especially with high injection temperatures) are somewhat more flexible in terms of increasing cavity wall thickness and reducing pressure. Gates are also designed differently and tunnel and point gates should be avoided. Direct gates, fan gates, and swing gates should be increased to three times the normal size. The flow direction of the polymer inside the printing mold should be aligned with the 3D printing line to avoid sticking and high filling caused by low pressure. The cooling system can improve the life of the mold to some extent, but it will not significantly reduce the number of cycles of the printed mold because the heat dissipation ability of the 3D printed mold is not as good as that of the aluminum or steel mold.
In summary, 3D printing technology will not completely replace the position of traditional mold manufacturing. Because 3D printing mold in the finished product quality, product cost, and mold design compared with the traditional mold manufacturing, there are still some shortcomings. And, 3D printing is also not suitable for mass production, the production of 1 piece and the production of 10,000 pieces of the cost of the unit price is close, and 3D printing requires a longer time. The current 3D printing technology can only be for small batch production cycle requirements of tight mold production, high-volume production, or traditional mold manufacturing.