surface treatment

CNC Surface Treatment Process

The following is a detailed technical description and industry application analysis of CNC surface treatment processes:

1. Surface Roughness Grade Standards

--Ra 3.2μm: Suitable for consumer parts, with visible tool marks, meeting the requirements of general mechanical components.

--Ra 1.6μm: A common standard in the machinery industry, suitable for low-speed, light-load moving parts.

--Ra 0.8μm: Parts requiring high precision, such as automotive parts and consumer electronics.

Ra 0.4μm: Nearly mirror-like finish, suitable for high-speed rotating parts such as bearings.

2. Key Processes

--Sandblasting: Surface roughness is altered by high-speed abrasive jetting. Suitable for titanium alloy implants (Ra 0.8-1.6μm)

--Acid etching: Combined with sandblasting (SLA process) to improve titanium alloy bone bonding

--Mirror polishing: Medical catheter stents and other applications require a Ra ≤ 0.2μm to reduce residual drug residue

--Coating: Hydroxyapatite coating enhances bioactivity and is suitable for orthopedic implants

3. Typical Application Scenarios

--Medical implants: Titanium alloy thread surfaces require a Ra ≤ 0.4μm to reduce tissue compatibility risks

--Surgical instruments: Syringe pistons require a Ra ≤ 0.2μm to reduce residual drug residue

--Electronic equipment: MRI gradient coil substrates require a flatness of ±10μm

4. Process Selection Criteria

--Functional Requirements: Mirror finishing with a Ra ≤ 0.4μm is preferred for high-speed rotating components

--Biocompatibility: Components that contact the human body require specialized coating processes

--Cost Control: The processing cost of a Ra 3.2μm surface is only 100% of the cost of a Ra 3.2μm surface finish. 30% of 0.4μm

Our Products

powder spraying

spray paint

Color anodizing

galvanized

polishing

gold plating

CNC machining services also offers a range of surface finishes to enhance the appearance and performance of your CNC machined parts. Below are the finishes, their colors, descriptions, and applicable materials:

Surface Finish	Color	Description	Materials	Application Areas
As-Machined	N/a	Parts are left with visible tool marks from the machining process.	Metals, Plastics	General parts, exterior parts
Anodizing	Clear, Black, Custom	Electrochemical process that adds a corrosion-resistant oxide layer.	Aluminum	Casings, body parts
Sand Blasting	Matte Gray	Creates a smooth, matte texture by blasting the surface with abrasives.	Metals, Plastics	Aerospace, consumer electronics
Powder Coating	Custom Colors	Durable, uniform color coating applied via electrostatic spraying.	Metals	Electronic parts, decorative parts
Electropolishing	Shiny Metal	Electrochemical polishing for a smooth, bright finish with reduced roughness.	Stainless Steel, Aluminum	Industrial equipment, home appliance casings
Brushing	Metallic	Satin finish with visible brush marks that create a uniform grain.	Metals	Small-batch custom exterior parts
Polishing	High Gloss	Buffing process that produces a mirror-like, reflective finish.	Metals, Plastics	Exterior parts for electronic products
Electroplating	Silver, Gold, Nickel	Adds a thin layer of another metal for enhanced durability and appearance.	Steel, Copper, Brass	Tools, gears
Black Oxide	Black	Dark, mild corrosion-resistant coating for steel and stainless steel.	Steel, Stainless Steel	Food processing machinery, medical devices
Passivation	N/A	Chemical treatment that improves corrosion resistance, particularly for stainless steel.	Stainless Steel	Gears, shaft parts
Heat Treatment	N/A	Controlled heating and cooling process to modify material properties like hardness.	Steel, Aluminum, Titanium	Bicycle parts, hardware

Our CNC Machining General Tolerance

Precision and reliability in every detail—our CNC machining general tolerance ensures consistent quality for every project.