Recently, a researcher from the Jiangsu Provincial Key Laboratory of 3D Printing Equipment and Applications of Nantong Institute of Technology published a paper entitled “Research on FDM Artificial Post-Processing Technology”. Because FDM 3D printing has a “step effect”, the surface of the printed part is rough, the stripes are obvious, and the surface quality is poor, which cannot meet the customer’s requirements, so post-processing is very important.
This article mainly studies and summarizes the manual post-processing technology of FDM printed parts, and provides specific implementation methods of post-processing, which provides reference for post-processing of FDM molded parts and other molding processes. In order to “further improve the surface quality and strength of the 3D printed model”, post-processing is usually required.
.Organic solvent chemical treatment
. Mechanical treatment with sander or grinder
. Surface coating treatment
In this article, the researchers focused on the manual post-processing process, which requires several items to work properly, such as an airbrush air pump with a gas tank, coloring pens and tool kits, gloves, masks, and dilution water. The solvent in the solvent bottle, a small amount of quick-drying filled soil, 80 to 3000 mesh sandpaper, detergent, files, etc. The team used PLA materials and an Einstart 3D printer to create a post-processing vase model as an example. After the vases were printed, they removed the plates with models from the printer.
“…Smoothly remove the model from the base plate with a shovel, then check if there is a strain concentration model, use a small wire stripper to weaken the model and the bracket first, and then use long pliers to clamp the direction The stent, applying a constant force, the location of the tiny stent can be removed using a file.” They wrote.
To clean the rough surface, the researchers pointed out that you can use low-mesh sandpaper for sanding and polishing. The model and low-mesh sandpaper should be immersed in water and polished along the model texture, because this can not only extend the service life of the sandpaper, but also make the model surface smooth. Then, they continued to use a technique called quick-drying small filling, which involves adding a small amount of filling material in the gaps of the model. Then, apply the filler evenly with a hard spatula.
The researchers wrote: “Then, after filling the soil to harden, wait 30 seconds and use 1200 to 1500 mesh sandpaper, as shown in Figure 8. If there are still small grooves, please repeat the above steps. After the area is filled with grooves in the soil, it feels smooth and you can continue to the next step.”
The next step is to spray water to irrigate the soil. First, rinse the surface of the model with water, then fill the soil with a watering can, then wipe the model with a non-woven cloth and spray in the “ventilated position”, keeping the nozzle about 20 cm. And quickly and evenly spray 1 to 3 times. The team explained: “Usually, choose a gray spray pot of water to fill the soil, because gray is a neutral color.”
After spraying water and filling the soil, it is air dried. Then, before entering the coloring stage, apply 2000-3000 high mesh sandpaper in one direction for “light grinding”. 3D printed, polished and processed models should be washed and dried before applying paint. You can use a spray gun to add basic colors or colors that cover most of the model. You need to spray at a ratio of 1:2 thinner and pigment, and you should be able to adjust the amount of air injected during spraying.
The team wrote: “Brushes of different thicknesses and sizes can be used to draw details. You can use 00000 pens to draw on the detailed parts of the graphic, or you can use cover tapes of different widths to cover, and then spray paint. After the spray paint is completely dry, you can spray the protective paint evenly on the model. The research team used B603 water-based matting agent for 3D printing vases.
The team also shared some notes about making the post-processing process run smoothly, such as the use of software to reduce the number of unnecessary support structures, the model is coated with a thin layer of glue on the plate during printing to prevent deformation and to observe the printing the importance of the process.
In the manual post-processing, attention should be paid to the protection work. The water mill is the best model processing method, be patient, 80-2500 mesh, use each mesh of sandpaper from long to short, along the model texture, should be high Mesh sandpaper polished and turned. When mixing colors, you should understand the relationship between light and dark, the brightness and purity of various colors, and the choice of cold and warm colors in advance. They pointed out that the “difficulty” of the post-processing method and the method itself may be different for different 3D printing technologies-the method applicable to FDM printer is not necessarily applicable to SLA, and so on.
Recommended reading 《Test drugs on 3D printed heart tissue》