What is the principle of 3D printing?
3D printing is based on the computer 3D design model, which is discretely decomposed into several layers of plane slices by software, and then the powder, liquid or filamentous metal, ceramics, plastics, cell tissue and other materials are stacked and bonded layer by layer by the NC forming system by means of laser beam and hot-melt nozzle, and finally superimposed and formed to produce solid products.
The specific steps of 3D printing are as follows:
Method / step 1:
Generally speaking, 3D modeling is to build a model with three-dimensional data from the virtual three-dimensional space through three-dimensional production software. For example, if you want to print a mobile phone case, you need a 3D printing model of the mobile phone case. So, how to get the 3D model of the mobile phone case?
1. Direct download model
Now there are many 3D model websites on the Internet. There are many kinds and quantities. You can download a variety of 3D models, and basically they can be used for 3D printing directly.
2. Reverse engineering modeling through 3D scanner
3D scanner reverse engineering modeling is to scan the real object through the scanner to obtain 3D data, and then process and repair. It can accurately describe a series of coordinate data of the three-dimensional structure of the object, and input it into the 3D software to completely restore the 3D model of the object.
3. Modeling with modeling software
At present, there are many 3D modeling software in the market, such as 3DMAX, Maya, CAD and so on, which can be used for 3D modeling. In addition, some 3D printer manufacturers also provide 3D model making software.
Method / step 2:
What is slicing? Slicing is actually cutting your 3D model into pieces, designing the printing path (filling density, angle, shell, etc.), and storing the sliced file into. Gcode format, a file format that can be directly read and used by 3D printer. Then, through the 3D printer control software, send the. Gcode file to the printer and control the parameters of the 3D printer to complete printing. Its function is to communicate with 3D printers.
Method / step 3:
Start the 3D printer, transfer the model sliced in STL format to get the gcode file to the 3D printer by means of data line, SD card, etc. at the same time, load the 3D printing materials, debug the printing platform, set the printing parameters, and then the printer starts to work. The materials will be printed layer by layer, and the layers are bonded by special glue, The pattern is fixed according to the cross section, and the last layer is superimposed layer by layer, just like building a house. The bricks are layer by layer, but when they are accumulated, they become a three-dimensional house. Finally, after layer by layer printing, layer by layer bonding and layer by layer stacking, a complete item will appear in front of us. The biggest difference between 3D printer and traditional printer is that the "ink" it uses is a real raw material.
Method / step 4:
Finish printing, post-processing
After the 3D printer completes its work, take out the object for post-processing. For example, when printing some suspended structures, a supporting structure needs to be propped up, and then the part above the suspended structure can be printed. Therefore, this part of redundant support needs to be removed for post-treatment.
Secondly, sometimes the surface of 3D printed articles will be rough (such as SLS metal printing) and need polishing. Polishing methods include physical polishing and chemical polishing. Sanding, beading and vapor smoothing are commonly used.
In addition, except that 3DP printing technology can achieve color 3D printing, others can only print a single color. Sometimes printed objects need to be colored, such as ABS plastic, photosensitive resin, nylon, metal, etc. different materials need to use different pigments.
Other treatment: after the 3D printing powder material process is completed, some follow-up treatment measures are required to strengthen the molding strength of the mold and prolong the storage time, mainly including standing, forced curing, powder removal, coating, etc. After the printing process, the printing mold needs to stand for a period of time, so that the formed powder and binder can be cured completely through cross-linking reaction and intermolecular force, especially for the powder with gypsum or cement as the main component.
The primary condition of forming is the hardening between powder and water, and then the strengthening of the binder part. A certain period of standing has an important impact on the final forming effect. When the mold has preliminary hardness, additional measures can be used to further strengthen the force according to different categories, such as heating, vacuum drying, ultraviolet irradiation, etc. After the completion of this process, the prepared mold has strong hardness, so it is necessary to remove other powder on the surface. Sweep most of the surrounding powder with a brush, and the remaining small powder can be removed by mechanical vibration, microwave vibration, wind blowing in different directions, etc. It is also reported that the mold is immersed in a special solvent, which can dissolve the scattered powder, but can not dissolve the solidified mold. The purpose of removing excess powder can be achieved.
For the mold after powder removal. Especially for molds made of gypsum based, ceramic based and other water absorbent materials, it is also necessary to consider their long-term preservation. The common method is to brush a layer of waterproof curing adhesive outside the mold to increase its strength and prevent it from weakening due to water absorption. Or immerse the mold into a protective polymer, such as epoxy resin, cyanoacrylate, molten paraffin, etc. the final mold can be waterproof, firm, beautiful and not easy to deform.