A component can have many kinds of CNC machining schemes, and the programming is very complicated. 3D printing, on the other hand, only has a small effect on the processing time of consumables because of the placement position, which is relatively simple.
Differences in post processing
There are not many post-processing options for 3D printed parts, generally grinding, sandblasting, deburring, dyeing, etc. There are various post-processing options for CNC machined parts, in addition to grinding, oil injection, deburring, electroplating, silk screen printing, pad printing, metal oxidation, laser engraving, sandblasting and so on.
CNC machining and 3D printing each have their own advantages and disadvantages. It is more important to choose the appropriate processing technology.
The difference between 3D printing technology and injection molding technology
Plastic injection molding refers to a method in which a completely molten plastic material is stirred by a screw at a certain temperature, injected into a mold cavity with high pressure, and cooled and solidified to obtain a molded product. This process started in the 1920s and has a development history of nearly a hundred years. It is a very widely used and very mature industrial manufacturing technology.
In the plastics manufacturing industry, 3D printing and injection molding are often used as PK, and there are many remarks that 3D printing is the terminator of injection molding. For manufacturers, the competitiveness of the two is one of the topics they are most concerned about. So, what is the difference between 3D printing technology and injection molding?
production mode
As long as there is an injection mold in the injection molding process, standardized products can be produced at low cost and on a large scale. Therefore, injection molding is still the best choice for traditional high-volume, large-scale manufacturing.
Injection molding principle
The 3D printer does not need traditional tools, fixtures, machine tools or any molds, and can directly convert any shape of the computer into a physical model automatically, quickly, directly and accurately. Thanks to the large size of the 3D printer Different from the characteristics of the traditional injection molding process, the more complex and non-solid objects are, the faster the processing speed is, and the more raw material costs are saved, so they are better at the manufacture of personalized and diversified products.
manufacturing cost
Due to the wide availability of raw materials for injection molding, and its large-scale and rapid standardized production characteristics, it is also conducive to reducing the cost of a single product. Therefore, in terms of manufacturing cost, the cost of injection molding is much lower than that of 3D printing technology.
However, for industrial manufacturing, the real cost-saving link of 3D printing lies in the modification of the prototype. Modifying the prototype only requires modifying the CAD model and will not incur any manufacturing costs.
In injection molding, if the prototype is a steel mold, the modification cost will be relatively low, but if an aluminum alloy mold tool is used, the cost will be much higher. This is also the reason why many companies or individuals engaged in mold design currently choose 3D printers for mold design and printing.
Application field
Currently, the injection molding process enables mass production of objects with consistent shapes, making it ideal for mass production of standardized products.
3D printing only needs to input three-dimensional images through the control terminal, and then the raw materials can be printed into physical models, and even parts or molds can be directly manufactured, thus effectively shortening the product development cycle. At present, 3D printing has been widely used in makers, architectural design, mold model design and other fields.
Binder jet metal 3D printing vs. injection molding
Metal Injection Molding (MIM) is a powerful manufacturing process for high-volume production of metal parts. But binder jet metal 3D printing offers a compelling alternative with its unique advantages.
Binder jet metal 3D printing uses an array of nozzles to slice the CAD model to obtain a series of two-dimensional data. According to the two-dimensional pattern obtained by slicing, the binder is selectively sprayed in the metal powder bed to solidify and form, and the entire initial blank part is fabricated by stacking layer by layer. Then, the pre-sintered parts are pre-sintered to obtain a certain strength, and then the powder is cleaned. Finally, high-temperature sintering removes the binder and achieves fusion between powder particles, thereby obtaining high-density and high-strength parts. There are both similarities and differences between the two technologies.
Similarities and differences between binder jet metal 3D printing and injection molding
First of all, the design constraints of 3D printing are few, and the characteristics of manufacturing parts layer by layer make the technology have better design freedom. In principle, the printing of various complex shapes can be realized. This also means that several parts can be integrated - several connectors can be replaced by one part, but achieve the same function - reducing the number of parts and shortening assembly time. The design of MIM needs to consider part demoulding, so some shapes are limited, and complex structural parts cannot be manufactured like 3D printing. However, due to the influence of gravity, friction and shrinkage, the post-sintering process of binder jet metal 3D printing is not good at processing large-area thin-walled parts without a support structure, nor is it good at manufacturing twig tree-like parts.
Principle of Binder Jet Metal 3D Printing and Injection Molding
Secondly, the molding process is different. The binder jet metal 3D printing is formed by selectively spraying the binder with the array nozzle, while the MIM adopts the mold injection molding. However, the post-treatment process of the two is the same, and both require high-temperature sintering. After sintering, the density of 3D printed parts can reach more than 98%, which is similar to the MIM process. However, since MIM requires a special degreasing process, it is determined that it is impossible to make very thick parts.
Third, binder jet metal 3D printing has fewer fabrication steps than MIM. MIM requires mold opening, while binder jet metal 3D printing can directly print parts. Because the processing speed for small batches is significantly better than the MIM process. Also, once the MIM mold is finished, it is not easy to adjust. So many iterations of metal 3D printing can be done without adding cost.
How to choose between binder jet metal 3D printing and MIM?
In most cases, how to choose, mainly depends on the output. For prototyping and small batch production, such as tens of thousands of pieces, choosing the former is a good choice. But MIM is more cost-effective in mass production, for example, MIM process can be selected for hundreds of thousands of pieces.
Besides yield being the decisive factor, there are other reasons.
Due to degreasing limitations, MIM cannot make parts that are too large and thick. Generally, the mass of MIM parts is below 500g, so for large-sized parts, 3D printing is preferred.
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