With the continuous development of 3D printing technology, its application scope is getting wider and wider, from industrial manufacturing to personal creative production, which has been widely used. However, although 3D printing technology can achieve complex structure and fine details, the surface of the parts that have just been printed often has problems such as layering, burr and unevenness, which affect its appearance and performance. Therefore, proper polishing of 3D printed parts is an important step to improve product quality and aesthetics.

First, the significance of 3D printing polishing

Polishing can not only improve the appearance of 3D printed parts, make them smoother and more delicate, but also improve the surface quality of parts, reduce the friction coefficient and enhance their functionality and durability. For some parts that need high-precision fitting, such as gears and dies, polishing can remove tiny bumps and edge burrs produced in the printing process, and improve their fitting accuracy and performance.

Second, the common polishing methods

Step 1 polish by hand
Manual polishing is the most basic polishing method, which is suitable for all kinds of materials. Usually, sandpaper with different particle sizes (for example, from 200 mesh to 2000 mesh) is used for grinding step by step. First, the layering and burr are removed by rough grinding, and then the smooth effect is achieved by fine grinding. This method has low cost and simple operation, but it takes a long time and its effect depends on the experience of the operator.

2. Chemical polishing
Chemical polishing is mainly suitable for thermoplastic materials such as ABS and PLA. By soaking the printed part in a specific chemical solvent (such as acetone for ABS), the surface is slightly soluble and re-leveled, so as to achieve a smooth effect. This method has high efficiency and uniform effect, but it needs to pay attention to ventilation and safety protection, and is not suitable for complex structures or thin-walled parts.

3. Vibration polishing
Vibration polishing is to put printed parts and abrasives into a vibration polishing machine, and use vibration friction to remove surface burrs and unevenness. This method is suitable for a large number of small parts, with high efficiency and little damage to the workpiece, but the equipment investment is large, and it is necessary to choose the appropriate abrasive.

4. Sand blasting
Sand blasting is to spray fine particles onto the surface of printed parts through high-pressure air flow to achieve the purpose of cleaning and polishing. This method can effectively remove the residual supporting structure and surface impurities, and is suitable for a variety of materials, but the surface will be slightly rough after treatment, which may affect the dimensional accuracy.

5. Automatic polishing robot
For high precision or mass production requirements, automatic polishing robots can be used. Through programming to control the polishing path and strength, efficient and consistent polishing effect can be achieved. Although the equipment cost is high, it has obvious advantages in industrial production.

Three, after polishing treatment and matters needing attention

After polishing is completed, it is recommended to clean, remove polishing residues and chemical solvents, and spray paint or paint if necessary to improve the appearance. At the same time, we should pay attention to the following points:
-Understand the characteristics of printing materials and choose the appropriate polishing method;
-For parts with complicated details, avoid structural damage caused by excessive grinding;
-Use protective equipment, especially in chemical polishing;
-Choose the polishing grade according to the purpose. The polishing requirements of functional parts and display parts are different.

IV. Conclusion

To sum up, the polishing of 3D printed parts is a post-processing link that cannot be ignored. Through reasonable polishing methods, not only the aesthetic appearance of printed products can be improved, but also their performance can be significantly improved. With the continuous development of 3D printing industry, there will be more intelligent and automated polishing technologies and equipment in the future, which will provide strong support for 3D printing products to move towards higher quality.