Yumoto Vietnam provides a one-stop CNC machining service with a wide range of surface finishing options. In precision machining, surface finishing is an essential step that makes products more durable, visually appealing, and function more effectively. In this article, we will showcase some of the most common types of finishing we offer.
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Below are some of the surface finishes available for our machined metal components. We outsource all of our surface finishes to selected local partner companies that have been carefully screened for quality. We can also provide other treatment and post-processing methods beyond those listed here upon customer request.
| As-machined | As-machined parts may show some tool marks, but surface will be smooth to the touch. Surface roughness usually ranges from Ra1.6~3.2 micrometer (Ra63~125 microinches). Lower surface roughness requires grinding or polishing finishing. |
| Anodizing Type II (clear, black or color) | Anodizing Type II finishing creates an aluminum oxide on the surface, which helps protects against corrosion. It can also be used to enhance the appearance of the machined products. Our supplier's anodizing process follows MIL-A-8625F, and they can supply Certificate of Conformance (COC) if needed. |
| Anodizing Type III (hard) | Hard anodizing finishing creates an oxide layer that is thicker, harder and more durable than anodizing type II. Thickness can range from 10 to 100 micrometers. We can provide from a lower hardness of HRC35 to hardness of up to HRC70, which matches that of heat-treated steel. |
| Sand Blasting | Sand blasting is a finishing process that uses high-pressure air to shoot abrasive sand particles against the surface of the machined component. It is an effective method to remove machined tool marks, which results in a uniform surface finish. You can do this before anodizing to create a matte finish. |
| Alodine (clear and yellow) | Alodine is a type of conversion coating for aluminum parts that creates a thin chromate protective film on the metal. We have #1000 (colorless) and #1200 (yellow). |
| Electroless nickel plating | This surface finishing process deposits a uniform layer of nickel-phosphorus. This plating does not require electric current like most other plating processes, which results in a uniform thickness and a thickness tolerance of +/- 1μ. |
| Trivalent Chromate Zinc Plating (bluish white, yellow, black) | This surface finish is also referred to as Unichrome Plating, and we offer three colors (bluish white, yellow, and black). Electric current is used to deposit the plating on the surface. It is not very suitable for precision parts that require very tight dimensional tolerance. |
| Black Oxide Coating | Black oxide coating is a type of conversion coating that can be applied to steel components. Generally the coating will result in a nice, uniform black color, but for steel parts that have been heat treated, there may be some color variations on the surface. |
We can also do hard chrome plating, flat surface grinding, cylindrical grinding, electropolishing (EP), buff polishing #400 and #600, passivation and many more!
This product was designed to showcase our dream to take our precision technology to space. The base part and the rocket booster in the middle has clear anodizing, the main spacecraft or orbiter has yellow color anodizing, and the two solid rocket boosters on the sides have black anodizing.
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This is an A6061 machined part with anodizing type II navy color. The surface has been sandblasted for uniform finish.
Another color anodized part made out of A5052 material.
Our suppliers can do a wide range of colors for anodizing. Below is a picture provided by one of our anodizing suppliers.
This is an inspection jig we machined from A5052 material with hard anodizing.
These are simple CNC machined parts we made to test the alodine plating. Alodine #1000 is clear color, while alodine #1200 is dark yellow.
We CNC machined these components from stainless steel SUS304 to test the trivalent chromate zinc plating. Starting from the left, you see the bluish-white zinc plating, then the yellow plating, and finally the black plating.
We machined this component using SS400 steel and used black trivalent chromate finishing.
Here is another SS400 machined component. This one has the bluish-white finishing (also known as Unichrome plating).
This product was made by S45C-H thermal refined steel. We did induction heating of HRC37~43 at one end of the product before doing the black oxide coating.
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After CNC machining, this SKH51 (YXM1) steel product was vacuum heat-treated to achieve a hardness of HRC 61–64. Next, the dimensions were fine-tuned through precision grinding to meet the required tolerance of ± 0.01 mm. Finally, the surface is coated with a protective layer of titanium nitride (TiN) to enhance durability and wear resistance.
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Where are your surface finish suppliers located?
All our surface finish suppliers are located in either Ho Chi Minh Province or Tay Ninh Province. We always do our best to look for suppliers that are close to our factory in Tay Ninh Province to reduce our lead times and ensure quick resolution whenever there is any problem.
How do you ensure the quality of the surface finish?
Whenever we find a new supplier for surface finish, we always visit their factory to make sure they have strict quality control procedures in place and request them to do surface finish on a sample product. For our regular surface finish suppliers, we hold regular meetings in order to discuss any quality issues and ways to improve in the future.
We inspect outer appearance of 100% of the products before and after surface finish.
Can you send us a test piece of the surface finish?
We can machine 1 unit of your product first to try out the surface finish.
If you would like to save costs on the test surface finish, we could also machine a simple small block product to do the test and send you a picture. We can also deliver the block product for you to see it in person, but we kindly ask that you cover the shipping fee.
Below is a picture of a simple A6061 small block (T10 x 50 x 50 mm) we machined with sandblasting and black anodizing. We delivered this sample product to our client in the US who wanted to see the anodizing finish in person.
What is the average lead time for the surface finish?
In general, the lead time for quantities below 100 units is about 3~5 business days. Most of our suppliers operate six days a week from Mondays to Saturdays. For rapid prototypes of small quantities, our suppliers can do the surface finish in 2~3 business days.
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