CNC machining produces parts that have tight tolerance and very fine details from different plastic or metal materials. The subtractive nature of the machining however leaves minor marks on the surface of the parts and finishing is therefore necessary to improve in the surface roughness, wear resistance or the visual property of the parts. There are different surface treatments for the metal parts that are CNC machined and each comes with its own advantages. Below is a brief overview of the most common surface finish treatments and their advantages.
Powder coating
This surface treatment for the metal parts adds thing protective polymer layer on the surface. The coating is wear resistant and string finish that is highly compatible with all metal materials. The process is very similar to spray painting only that the paint in this case is dry powder and not the usual liquid. To increase corrosion resistance, the parts are primed with phosphating or chromating coat before the dry powder coating is done with an electrostatic gun. It is then cured at high temperatures. Multiple layers can be done on the parts to create thick coating depending on the preferences or requirements for the metal parts.
The advantages
- It has higher impact resistance especially compared to anodizing
- It is available in multiple colors
- Compatible with most metal materials
- Offer strong wear and corrosion coating for different functional applications.
Bead blasting
This surface finishing treatment adds matte or satin finish uniformly onto the surface of the CNC machined parts thus removing the marks in the process. Small glass beads are presented to the surface with the help of a pressurized air gun removing small amounts of material and smoothing out the surface. Surface features such as holes are masked so that dimensional changes are eliminated. This treatment is however best for visual purpose the end result will depend on how skilled the operator is. The glass beads are available in different sizes.
The advantages
- It is a low cost surface treatment method
- It offers uniform satin or matte finish for the metal parts
Anodizing
In this surface treatment, a thin ceramic layer is added onto the surface of the metal parts to offer protection from wear and corrosion. The added anodize coating is usually electrically non-conductive and is very hard. This treatment is mostly compatible with titanium and aluminum parts. The parts can be dyed to different colors depending on the requirements and sealed to give them that aesthetic appeal. Coating thickness can also be altered by variations in solution temperature, consistency, electric current and anodizing time. It is also important to know that the anodizing can be in type II or type III the difference usually being the thickness of the ceramic coating.
The advantages
- It offer aesthetically pleasing and durable coating
- It can be applied easily even on internal cavities and small sized parts
- It provides good dimensional control
- The coating is high wear resistant making it suitable for top end engineering applications
A reputable CNC machining company in China should be able to meet all your project requirements. To find the best CNC machining services China supplier you should check out what the company you are about to choose can do for you.
For more details, please refer to http://www.cncmachinings.com.
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