Will 3D printing replace traditional mold manufacturing?

Summary: Mold is known as the "mother of indust […] Mold is known as the "mother of industry", and its application can be traced back to ancient times. In the past few decades, as the wheels of the technological revolution roll forward, the mold manufacturing industry has opened a new chapter and technology has been advancing by leaps and bounds , Has made a huge contribution to the processing and manufacturing industry. Nowadays, although traditional manufacturing industries around the world still use molds as the main production force, the development of molds has been impacted by 3D printing technology. In recent years, with the development of Industry 4.0, China's manufacturing industry has developed more and more rapidly from "manufacturing" to "intelligent manufacturing". 3D printing technology has been widely used in my country's manufacturing industry. 3D printers can be used as molds. Design and manufacturing provide efficient and low-cost support. Even with the rapid development of 3D printing technology, in some areas, it has gradually begun to subvert mold technology and form direct competition with it.

It is understood that 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, and the certification of many components will take a lot of time. This will put new products in a very disadvantageous position in terms of time to seize the market. The 3D printing injection mold is an efficient solution.

Under normal circumstances, it takes several weeks to two months to produce a mold, and the use of 3D printing technology can complete the mold prototype in a few hours, and can be modified immediately based on the test results. Then the final product samples are 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 products have passed the certification, which greatly shortens the development cycle.

In the field of mass production, the comparison between 3D printers and traditional molds:

Traditional mold

1. Mold durability: In production applications, molds must be wear-resistant and economical. Therefore, most molds are made of steel, and some are even made of cemented carbide. To

2. Mold manufacturing: Use 3D modeling software such as PRO-E to draw the mold diagram, and continuously adjust to achieve the final molding effect.

3. Mold usage: Mainly traditional injection molding, die-casting, rubber and stamping products.

4. Mold strength accuracy: confirm the strength according to the actual needs of users, and the accuracy is high. To
5. Mold production time: relatively fast.

6. Mould economy: The economy of mass production is good, and the economy of single piece and small batch is poor.

3D printing technology

1. Materials required for 3D printing: consider the most suitable printing materials according to the actual needs of users.

2. 3D printing molding method: cumulative type, adding up little by little, and finally printing the finished work.

3. 3D printing purpose: small and complex parts can be easily realized by 3D printing, and large parts can be printed together as a whole.

4. 3D printing strength accuracy: There are many comprehensive factors regarding the strength and accuracy of 3D printing. The accuracy of the 3D printer, the quality of the selected materials, and the accuracy of the 3D model diagram all determine the accuracy of the final product, and the strength is acceptable.

5. 3D printing production time: longer molding time.

6. 3D printing economy: the economy of mass production is poor, and the economy of single piece and small batch is good.

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 comes out. 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 destroyed very quickly under the thermal cycle of injection molding. In fact, 3D printing molds usually fail within 100 times of use in mild environments, 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 their 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. However, 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. On the other hand, regardless of the plastic 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 mold injection plastic parts are facing challenges, and extra care is needed for the number and installation location of plastic mold ejectors. In terms of increasing the cavity wall thickness and reducing pressure, 3D printing molds (especially high injection temperatures) are somewhat more flexible. 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 improve 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 still 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 requires 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.

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