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3D Cnc Machine

3D Cnc Machine, also known as 3D Printer (3DP for short) is a process of Rapid Prototyping (RP), which uses layer-by-layer stacking to create a three-dimensional model. Its operation process is similar to that of a traditional printer. It’s just that traditional printers print ink on paper to form a two-dimensional plan drawing, while three-dimensional printers use liquid photosensitive resin materials, molten plastic filaments, gypsum powder and other materials to achieve layering by spraying adhesives or extruding. Layers are stacked to form a three-dimensional solid.

  1. Rapid prototyping technology
  2. Process flow
  3. Development of 3D printing
  4. Print test
  5. Industry development

Rapid Prototyping Technology

Rapid prototyping technology (r referred to as RP), also known as rapid prototyping manufacturing technology, is an advanced manufacturing technology developed in recent years. Rapid prototyping technology originated in the United States in the 1980s and quickly developed to Japan and Europe. It is a major breakthrough in the field of manufacturing technology in recent years. Rapid prototyping is a digital forming technology based on the idea of ​​discrete accumulation forming; it is a technology integration of CAD, numerical control technology, laser cutter technology, and material science and engineering. It can automatically and quickly materialize design ideas into prototypes with certain structures and functions or directly manufacture parts, so that product designs can be quickly evaluated and modified to respond to market demand and improve the competitiveness of enterprises.

RP integrates advanced technologies such as CAD, CAM, CNC Machine, precision servo drive, optoelectronics, and new materials. According to the product three-dimensional model constructed by CAD, it slices it in layers to obtain the profile of each layer section. According to these contours, the laser beam selectively sprays and solidifies layers of liquid resin (or cuts layers of paper, or sinters layers of powder materials), or the spray source selectively sprays layers of adhesive Or hot-melt materials, etc., to form various cross-sections and gradually superimpose them into a three-dimensional product. It simplifies a complex three-dimensional processing into a combination of a series of two-dimensional processing.

Process flow

  • (1) Three-dimensional model construction. Because the RP system only accepts computer-constructed product three-dimensional models (stereographs) before slicing can be performed, CAD software (such as UG, Pro/E, I-DEAS, etc.) should be used on a PC or workstation. Etc.), design a 3D model according to product requirements; or convert the 2D and 3 views of an existing product into a 3D model; or in reverse engineering, use a measuring instrument to scan the existing product entity to obtain a data point cloud for 3D Refactoring.
  • (2) Approximate treatment of three-dimensional model Since there are often some irregular free-form surfaces on the product, it must be approximated before processing. The 3D model file obtained through approximate processing is called STL format file, which is composed of a series of connected spatial triangles. Typical CAD software has an interface for converting and outputting STL format files, but sometimes the output triangles will have a small amount of errors and need to be partially modified.
  • (3) Slicing of the three-dimensional model. Since the RP process is processed in accordance with the layered cross-sectional profile, the three-dimensional model must be discretized into a series of orderly two-dimensional layers along the forming height before processing. That is, slices are divided into layers at regular intervals in order to extract the contour of the section. The size of the interval is selected according to the requirements of accuracy and productivity. The smaller the interval, the higher the accuracy, but the longer the forming time. The interval range is 0.05-0.5 mm, 0.1 mm is commonly used, and a fairly smooth formed surface can be obtained. After the layer interval is selected, the thickness of each layer should be adapted to it during forming. Various forming systems are equipped with Slicing processing software, which can automatically extract the cross-sectional profile of the model.
  • (4) Section processing According to the layered section profile, under computer control, the forming head (such as laser scanning head or nozzle) in the RP system is controlled by the numerical control system, and the section profile is scanned in the xy plane to solidify the liquid resin. (Or cutting paper, sintering powder materials, spraying adhesives, hot melts and hot melt materials) to get a layer by layer section.
  • (5) Cross-section stacking After the cross-section of each layer is formed, the next layer of material is sent to the formed layer, and then the latter layer is formed and bonded with the previous layer, so that the cross-sections of each layer are gradually stacked. Together, the final three-dimensional product is formed.
  • (6) Post-processing After the forming machine is formed, the workpiece is taken out, polished, coated, or placed in a high-temperature furnace for sintering to further improve its strength (such as 3D-P process). For the SLS process, the workpiece is sintered in a high-temperature furnace to volatilize the binder for metal infiltration (such as copper infiltration).

3D printing development

3D printing, also known as three-dimensional printing, is explained in Wikipedia: a kind of rapid prototyping technology, which uses powdered metal or plastic and other bondable materials to print layer by layer. Construct zero objects. Mold manufacturing and industrial design are used to build models, and are now being developed into product manufacturing, forming “direct digital manufacturing.” Some high-value applications (such as hip joints or teeth, or aircraft parts) already have printed parts. “3D printing” means the popularization of this technology.
In the mid-1980s, SLS was developed and patented by Dr. Carl Deckard of the University of Texas at Austin. The project was sponsored by DARPA. In 1979, a similar process was patented by RF Housholder, but it was not commercialized.

In 1995, MIT coined the term “three-dimensional printing”. At the time, graduates Jim Bredt and Tim Anderson modified the inkjet printer solution to a solution that squeezed the constrained solvent into the powder bed instead of squeezing the ink. Scheme pressed on paper.

When it comes to 3D printing, you have to mention 3D printers:

A 3D printer, also known as a three-dimensional printer, is a cumulative manufacturing technology that produces three-dimensional objects by printing layers of adhesive materials. At this stage, 3D printers are used to manufacture samples. Since 2003, sales of 3D printers have gradually expanded, and prices have also begun to fall.
The technology can be used in jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automotive, aerospace, dental and medical industries, education, geographic information systems, civil engineering, and many other fields

Process principle: The printing process of each layer of 3D printing technology is divided into two steps. First, a layer of special glue is sprayed on the area to be formed. The glue droplets are small and difficult to spread. Then spray a uniform layer of powder. When the powder encounters glue, it will quickly solidify and bond, while the area without glue remains loose. In this way, under the alternate layer of glue and layer of powder, the solid model will be “printed” and formed. After printing, the model can be “planed out” by sweeping away the loose powder, and the remaining powder can be recycled.

The 3D printing technology uses glue and powder that are processed special materials, which not only require the curing reaction speed, but also have a direct impact on the strength of the model and the resolution of the “printing”.

Technical advantages: The most prominent advantage of 3D printing technology is that it can directly generate parts of any shape from computer graphics data without machining or any molds, thereby greatly shortening the product development cycle, increasing productivity and reducing production costs. Compared with traditional technology, 3D printing technology also has the following advantages:

The cost is reduced by abandoning the production line, and material waste is greatly reduced. Moreover, it can also create shapes that cannot be produced by traditional production techniques, allowing people to design aircraft wings or heat exchangers more effectively. In addition, with a good design concept and design process, three-dimensional printing technology can also simplify the manufacturing process, and produce a single item quickly, efficiently and cheaply.

In addition, compared with machine-made parts, the printed product is 60% lighter and equally strong.

Print test

On October 21, 2013, Professor Shen Haijun from the School of Aeronautics and Astronautics and Mechanics of Tongji University revealed that several teachers and students of the micro aircraft laboratory of the school successfully released a newly developed micro aircraft, and this aircraft adopted the latest 3D printing manufacturing technology. Professor Shen Haijun introduced that the successful test flight of a 3D printed micro-aircraft from Tongji University is the first in China. It demonstrates the feasibility of 3D printing technology in the field of micro-aircraft design and manufacturing.

Industrial Development

In the past, when foreign 3D CAD software monopolized the market, the sky-high cost discouraged many companies, which also made the proportion of designers proficient in 3D CAD software not high.

According to reports, with the rise of domestic 3D CAD software brands, such as Zhongwang 3D, CAXA and other domestic software, the overall market price has begun to fall within the acceptable range of enterprises. At the same time, 3D CAD technology is gradually showing the characteristics of simplicity and ease of use, and more and more people master professional 3D design. In the previous ZW 3D global Christmas design competition, many participants who used ZW 3D for the first time were able to design exquisite 3D works. ZW 3D also commissioned the domestic 3D printing professional information agency iCader to print the guitar works. Into a mini model, as a souvenir of the game. It is reported that ZW3D2013 version also added the function of docking with 3D printer.

The development prospects of 3D printing technology are limitless, but based on the current constraints, it still needs to be viewed rationally. As the domestic 3D CAD software and 3D printing technology are more and more perfected, I believe that 3D printing will not be just a gimmick, but will truly become the driving force of the third industrial revolution.

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