Structure diagram of diaper sensor
"Compared with 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 must pass stringent international standards and certifications before it goes on the market. The certification of many components will be time-consuming. This will put new products in a very disadvantageous position in terms of time to seize the market. 3D printing injection molds are an efficient solution. Well-known manufacturers Yi Mould do this In their open laboratory, they use 3D printing technology to make injection molds.” According to Luo Baihui, secretary general of the International Mould Association, it usually takes several weeks to two months to produce a mold, and 3D printing technology is used. The mold prototype can be completed within a few hours and can be modified immediately based on the test results. Then the final product sample is injection molded. These product samples can be sent directly for certification. At this time, traditional mold manufacturing may still be in production. Even before the mold is finalized, the 3D printed product has passed the certification, which greatly shortens the development cycle. Only in the mold production cycle, 3D printing technology has had a certain impact on traditional mold manufacturing.
However, industry experts said that although 3D printing technology has many advantages such as short production cycle, convenient raw materials, and uniform product pressure, 3D printing technology cannot completely replace traditional mold manufacturing methods. This is because 3D printing technology is still in the manufacturing process. There are some problems. For example, 3D printing technology is to process products layer by layer, which will shorten the production cycle of the mold, but at the same time it will also cause the surface of the mold to have a step effect. Direct printing molds also have similar problems, and later machining or sandblasting is required to eliminate these small, tooth-like edges. In addition, holes smaller than 1mm must be drilled, larger holes need to be reamed or drilled, and thread features need to be tapped or milled. These secondary processes greatly weaken the speed advantage of 3D printing molds.
At the same time, in order to ensure good material flow properties, the injection mold needs to be heated to a very high temperature. Aluminum molds and steel molds usually experience 500F (260°C) or even higher temperature environments, especially when processing high-temperature plastics such as PEEK and PEI materials. It is easy to produce thousands of parts with metal molds, and it can also be used as a transition mold before the final mass production mold is released. The mold materials manufactured using 3D printing technology are generally photosensitive or thermosetting resins, which are cured by ultraviolet light or laser. Although these plastic molds are relatively hard, they are damaged very quickly under the thermal cycling conditions of injection molding. In fact, 3D printed molds usually fail within 100 times of use in mild environments, such as high-temperature plastics such as polyethylene and or styrene. For glass filled with polycarbonate and high temperature resistant plastics, even only a few parts can be produced.
In addition, a major reason for using 3D printing molds is its low cost. The cost of production-level machining molds is generally US$20,000 or more, which means that the printing molds of US$1,000 are comparable. But this analogy is not fair. The evaluation of printing mold costs usually only considers material consumption, and does not consider labor, assembly and installation, injection systems, and hardware. For example, ProtoLabsd's aluminum mold can be used for production at a cost of $1,500. If you need to produce more parts, use 3D printing molds, and you need to reprint and test new molds with assembly machines every time 50-100 products are produced. On the other hand, regardless of the plastics used, aluminum molds usually still perform well after 10,000 parts have been produced. Therefore, in terms of production costs, 3D printing is not more cost-effective than traditional mold manufacturing methods.
In addition, in product design, the principles and practices of traditional injection mold manufacturing have a history of more than a century, and the industry has studied them thoroughly. For example, the draft angle must be greater than or equal to 5 degrees to meet most aluminum mold requirements. 3D printing molds for injection molding plastic parts are facing challenges. Extra care is required for the number and installation positions of plastic mold thimbles. In terms of increasing the cavity wall thickness and reducing pressure, 3D printing molds (especially high injection temperature) are more flexible to some extent. The gate design is also different, and tunnel and point gates should be avoided. Direct gate, fan gate, wing gate should be increased to 3 times the normal size. The flow direction of the polymer in the printing mold should be consistent with the 3D printing line to avoid high filling caused by viscosity and low pressure. The cooling system can increase the life of the mold to a certain extent, but it will not significantly reduce the cycle times of the printing mold, because the heat dissipation capacity of the 3D printing mold is not as good as the aluminum mold or the steel mold.
In summary, 3D printing technology will not completely replace the traditional mold manufacturing industry. Because 3D printing molds have certain shortcomings compared with traditional mold manufacturing in terms of finished product quality, product cost and mold design. Moreover, 3D printing is not suitable for mass production. The unit cost of producing 1 piece and producing 10,000 pieces is basically close, and 3D printing takes a long time. The current 3D printing technology can only target small-batch production cycle requirements for mold production, and mass production is still based on traditional mold manufacturing.