what is Sanding and Polishing on rapid prototype

Sanding and polishing are often used in rapid prototyping post-processing.what is Sanding and Polishing on rapid prototype?

Sanding
There are three methods for the post-processing and polishing of the prototype manufacturing process: mechanical grinding, dry grinding and wet grinding.

①Mechanical polishing: In order to improve work efficiency when constructing a large area, mechanical polishing methods, such as electric polishing machines (disc type, vibration type), can be used.

②Dry sanding: sand paper for sanding. It is suitable for the polishing of hard and brittle paint. The disadvantage is that a lot of dust will be generated during the operation, which affects environmental hygiene.

③Wet sanding: sand paper dipped in water or soapy water for sanding. Water milling can reduce wear marks, improve the smoothness of the coating, and save sandpaper and labor. However, when spraying the lower layer of paint after the water abrasion, first, wait for the water abrasion layer to dry completely before applying the lower layer of paint, otherwise the paint layer is easy to whiten. In addition, substrates with strong water absorption are not suitable for water milling.

There is also a kind of sanding: the painting requirements are marked as “light sanding”, such as sealing paint, old paint film recoating, after partial repairs, etc. At this time,finer sandpaper and skilled hands should be used to carry out “light sanding”. Otherwise, it is counterproductive.

When using sandpaper for manual sanding, the whole piece of sandpaper is generally cut into four. After each piece is folded in half, clamp the two ends with your thumb and little finger. In addition, press the three fingers flat on the sandpaper and sand the surface of the object back and forth. According to the sanding object, it can be changed at any time, and the cavities in the fingers and the expansion and contraction of the fingers can be used to polish the concave and convex areas and corners. When sanding a large area, you need to master the principle of “higher”. Use the palm to turn the sandpaper, or attach a slightly harder rubber such as a sponge or cork block. Use your thumb and forefinger to pinch the left and right end faces tightly, and place the sand flat. mill. The length of the sander’s nails should be moderate to avoid hurting the fingers during operation.

Polishing
3D printing surface finish – polishingIf your part requires a high quality and shiny finish, but the color or branding is not critical, then polishing might be the ideal finishing solution for your job. Polishing is especially applicable for parts 3D printed using an FDM process, because this filament extrusion technique results in parts with visible layers. There are different polishing approaches for different 3D printing materials. For instance, ABS and other petroleum-based filaments can be polished and smoothed by vaporizing a solvent.

Other materials, such as PLA, require a more manual approach that involves sanding and a polishing agent. Different types of polishing materials work for PLA 3D printed parts, including liquid metal polish or wax-based polishing materials. From there, the process is relatively straight forward, the polishing agent is carefully rubbed onto the part’s surface until the part is smooth. Using this approach can even result in a shiny mirror surface, transforming a dull surface texture into a highly aesthetic one.

The polishing process has three main functions:
①For the substrate, it is to remove the burrs, oil and dust on the surface of the substrate;
②For the surface of the putty scraped, the surface is generally rough and needs to be sanded to obtain a smoother surface, so sanding can reduce the surface roughness of the workpiece;
③Enhance the adhesion of the coating. Before spraying a new paint film, it is generally necessary to polish the old paint film after hard drying. Because the coating has poor adhesion on an excessively smooth surface, the mechanical adhesion of the coating can be enhanced after polishing.

The flawless gleam of a mirror polished Aluminum/Stainless Steel part, the smoothness of a semi-gloss or matte part, the high shine of a PMMA part— all are signs of a job done well. And all are made possible by the application of sandpaper. Without proper sanding, any imperfections will be magnified when the final finish coat (e.g. painting) is applied. Therefore, we often apply sanding finishing to prepare a good surface for painting or other finishing procedure.

WKproto is a professional rapid prototyping and low-volume production manufacture specializing in 3D printing, CNC machining, and Vacuum Casting. Our factory and parter factories enable rapid prototyping of designs from our customers and low volume production for market verification.

We have three factories. 3D printing factory meets the demands of most 3D printing services with 100 SLA machines, 10 SLS machines, 10 MJF machines, 10 SLM machines, and 20 FDM machines. CNC machining factories for processing metals, plastic and more materials with more than 200 machines for CNC milling/CNC lathes/EDM / Wire EDM and the Vacuum Casting factory is for low volume production for ABS、PC、PP、PE、PA、POM、PMMA、PVC.