3D printing services often also offer other services to its clients. This could for example be injection molding, which is a different manufacturing technique than 3D printing. Another possible option is a CNC service. CNC means Computer Numerical Control, it consists of multiple methods. This includes CNC milling and CNC turning, for example. Usually the surface of the workpiece will be worked on after the CNC machining has been finished. This can be done with the help of polishing. This refers to using mechanical, electrochemical, or chemical effects to reduce the surface roughness of a part. It is utilized to create a smooth and bright surface, which can be done in multiple ways. Three common polishing processes will be introduced below, including its advantages and disadvantages.
Chemical polishing
Chemical polishing is a method that is used to remove wear marks on the surface of a prototype. This is done by the chemical etching of chemical reagents. The equipment needed for this process is quite simple. On top of that, it is capable of processing thin tubes, while objects with complex shapes and deep holes can be chemical polished too. The production efficiency of this polishing method is high, which is another advantage. The chemical polishing quality unfortunately is not as good as another process called electrolytic polishing.
Electrolytic polishing
This is some sort of anodic polishing, while also being a type of electrolytic machining. It uses a principle in which the anode is first dissolved in a particular electrolyte, but it needs to have the right current density too. Due to this, it can also be referred to as electropolishing. At the moment, electrolytic polishing of stainless steel is favored by many companies, partially because it is an environmentally friendly process. Unfortunately, the electrolyte does have poor versatility, while the service life again is quite short.
Mechanical polishing
Mechanical polishing is used a lot in multiple manufacturing sectors. A polishing machine is used for this process, which mostly consists of a polishing disc and a motor. The products that should be polished are placed on the disc, although this does depend on the material. The wear masks will be eliminated due to the grinding and rolling action between the polishing powder. This way, the surface will become much smoother and shinier as well. The polishing surface may be uneven though, which is a disadvantage of mechanical polishing.
