3D printing (also known as additive manufacturing and build-up manufacturing) is a technology based on digital model files, which uses adhesive materials such as powder metal or plastic to construct objects by printing layer by layer. This technology was first proposed by the United States in the mid-1980s.
3D printing is often used in mold manufacturing, industrial design and other fields to make models, and then gradually used in the direct manufacturing of some products. [2] It has a far-reaching impact on the traditional technological process, production line, factory model and industrial chain combination, and is a representative subversive technology in manufacturing industry.
The working principle of the so-called 3D printer is basically the same as that of ordinary printers, but the printing materials are somewhat different. The printing materials of ordinary printers are ink and paper, while 3D printers are filled with different "printing materials" such as metal, ceramics, plastic and sand. After the printer is connected to the computer, the "printed materials" can be superimposed layer by layer through computer control, and the drawings can be turned into objects.
Generally speaking, a 3D printer is a device that can "print" real 3D objects, such as printing toy cars, printing various models and even food. The reason why it is popularly called "printer" refers to the technical principle of ordinary printers, because the process of layered processing is very similar to inkjet printing. This printing technology is called 3D stereoscopic printing technology.
There are many different technologies for 3D printing. The difference between them is that components are created in different layers in the form of usable materials. Commonly used materials for 3D printing include nylon glass fiber, durable nylon material, gypsum material, aluminum material, titanium alloy, stainless steel, silver plating, gold plating, rubber material, etc.
The process of 3D printing
1, 3D design
The design process of three-dimensional printing is: first, use computer modeling software to model, and then "divide" the built three-dimensional model into layers of sections, that is, slices, thus guiding the printer to print layer by layer.
The standard file format for collaboration between design software and printer is STL file format. STL files use triangular surfaces to approximate the surface of objects. The smaller the triangular surface, the higher the resolution of the generated surface. PLY is a scanner that scans the generated 3D files, and VRML or WRL files generated by PLY are often used as input files for full-color printing.
2. Slice processing
By reading the cross-section information in the document, the printer prints these cross-sections layer by layer with liquid, powder or sheet material, and then bonds the cross-sections of each layer together in various ways to form an entity. The characteristic of this technology is that almost any shape can be made.
The resolution of the thickness (i.e. Z direction) and plane direction (i.e. X-Y direction) of the cross section printed by the printer is calculated in dpi (pixels/inch) or microns.
Generally, the thickness is 100 micron, that is, 0.1mm. Some printers, such as ObjetConnex series and 3D Systems ProJet series, can print a thin layer of 16 micron. The plane direction can print a resolution similar to that of a laser printer. The diameter of printing "ink drops" is usually 50 to 100 micron.
According to the size and complexity of the model, it usually takes several hours to several days to make a model by traditional methods. The technology of 3D printing can shorten the time to several hours, which of course depends on the performance of the printer and the size and complexity of the model.
Traditional manufacturing technologies such as injection molding can produce a large number of polymer products at a lower cost, while three-dimensional printing technology can produce a relatively small number of products in a faster, more flexible and lower cost way. A desktop-sized three-dimensional printer can meet the needs of designers or concept development teams to make models.
3. Finish printing
The resolution of a 3D printer is sufficient for most applications (the surface may be rough, like a sawtooth in an image). In order to obtain higher-resolution articles, the following methods can be used: First, use the current 3D printer to print a slightly larger object, and then slightly polish the surface to obtain a "high-resolution" article with a smooth surface.
Some technologies can print multiple materials at the same time. Some technologies also use supports in the printing process. For example, when printing some inverted objects, you need to use something that is easy to remove (such as soluble objects) as a support.