Surface Finishing Services
What Surface Finishing Services Does XC Machining Provide?
XC Machining applies 15+ surface finishes to CNC machined, sheet metal, injection molded, and 3D printed parts — including anodizing, powder coating, electroplating, polishing, passivation, painting, and bead blasting with Ra values from 0.012 to 3.2 μm.
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What is Surface Finishing?
Surface finishing is any post-manufacturing process that modifies a part’s surface for corrosion protection, wear resistance, electrical conductivity, cosmetic appearance, or regulatory compliance. XC Machining applies finishes to aluminum, steel, stainless steel, titanium, copper, brass, and engineering plastics produced by CNC machining, sheet metal fabrication, injection molding, or 3D printing.
XC Machining finishes parts in-house — no outsourcing to third-party finishing shops. This means your finish specification is controlled by the same team that machined or molded your part, maintaining dimensional accuracy and eliminating handling damage from inter-facility transport.
What Surface Finishes Does XC Machining Offer?
Surface Finish | Ra Value | Coating Thickness | Compatible Materials | Corrosion Protection | Typical Lead Time |
As-Machined (Standard) | Ra 3.2 μm (125 μin) | N/A | All metals and plastics | None (bare surface) | 0 days (included with part) |
Bead Blasting | Ra 1.6–3.2 μm | N/A | All metals, some plastics | None | 1 day |
Anodizing Type II | Ra 0.8–1.6 μm | 5–25 μm oxide | Aluminum only | 336–500 hr salt spray | 2–3 days |
Anodizing Type III (Hard Coat) | Ra 1.6–3.2 μm | 25–80 μm oxide | Aluminum only | 500–1,000+ hr salt spray | 3–5 days |
Bead Blast + Anodized Color | Ra 1.6 μm | 5–25 μm oxide | Aluminum only | 336–500 hr salt spray | 2–3 days |
Powder Coating | Ra 1.6–3.2 μm | 60–120 μm polymer | Steel, aluminum, stainless | 500–1,000 hr salt spray | 2–3 days |
Spray Painting (Matte) | Ra 0.8–1.6 μm | 30–80 μm (primer + coat) | All metals and plastics | 200–500 hr salt spray | 2–3 days |
Spray Painting (High Gloss) | Ra 0.2–0.4 μm | 40–100 μm (primer + coat) | All metals and plastics | 200–500 hr salt spray | 2–3 days |
Brushed Finish | Ra 0.4–0.8 μm | N/A (surface treatment) | Aluminum, stainless steel | None (cosmetic only) | 1 day |
Polishing (Mirror) | Ra 0.012–0.1 μm | N/A (surface treatment) | All metals | None (cosmetic only) | 1–2 days |
Electropolishing | Ra 0.2–0.8 μm (32 μin) | Removes 5–25 μm | Stainless steel, titanium | Enhanced — removes surface inclusions | 2–3 days |
Nickel Plating (Electroless) | Ra 0.4–0.8 μm | 5–50 μm nickel | Steel, aluminum, copper, brass | 200–500 hr salt spray | 3–5 days |
Chrome Plating | Ra 0.1–0.4 μm | 0.25–50 μm chrome | Steel, aluminum, copper | 200–500 hr salt spray | 3–5 days |
Zinc Plating | Ra 0.8–1.6 μm | 5–25 μm zinc | Steel, carbon steel | 200–500 hr salt spray | 2–3 days |
Passivation | No change to Ra | Chemical treatment (no layer) | Stainless steel only | Enhanced — per ASTM A967 | 1–2 days |
Chemical Conversion (Chem Film / Alodine) | No change to Ra | 0.25–1 μm conversion layer | Aluminum only | 168 hr salt spray (MIL-DTL-5541) | 1–2 days |
Black Oxide | No change to Ra | 0.5–1.5 μm conversion layer | Steel, stainless steel | Mild — 50–100 hr salt spray | 1–2 days |
Silk Screening | N/A | Ink layer | All metals and plastics | N/A (decorative) | 2–3 days |
Laser Marking | N/A | No material added | All metals and plastics | N/A (permanent mark) | 1 day |
Why Should You Choose XC Machining for Surface Finishing?
XC Machining finishes parts in-house alongside CNC machining, injection molding, and sheet metal fabrication. This means your surface finish is applied by the same team that manufactured the part — no third-party finishing vendors, no transit damage, and no dimensional variance from re-fixturing at an external finisher.
XC Machining operates anodizing tanks (Type II and Type III), powder coating booth with curing oven, electroplating lines (nickel, chrome, zinc), polishing and buffing stations, bead blast cabinets, spray painting booths, and laser marking machines — all in-house at our Dongguan facility.
Our engineers recommend the optimal finish for your base material, operating environment, and cosmetic specification. Every finish recommendation includes Ra value, coating thickness, salt spray rating, and lead time — provided within 12 hours.
We review designs for masking requirements (areas that must remain unfinished for assembly fit), minimum feature size for coating penetration, hydrogen embrittlement risk on hardened steels, and dimensional growth from coating thickness. Free DFM feedback within 12 hours.
Finish quality is verified by: coating thickness gauge (magnetic/eddy current), Ra surface roughness tester, salt spray chamber (per ASTM B117), adhesion cross-hatch test (per ASTM D3359), and visual inspection under controlled lighting.
What Are the Most Common Surface Finishes at XC Machining?
XC Machining applies the following surface finishes to CNC machined, sheet metal, injection molded, and 3D printed parts. Each finish card includes Ra value, coating thickness, compatible materials, and typical applications.
Brushing creates a directional satin grain at Ra 0.4–0.8 μm on aluminum and stainless steel using 120–400 grit abrasive belts. Produces linear or circular patterns. Compatible with aluminum, steel, stainless, titanium, brass. Applications: consumer electronics panels, appliance faceplates, architectural hardware.
Black oxide deposits a 0.5–1.5 μm magnetite (Fe₃O₄) conversion layer on steel and stainless steel parts without dimensional change. Provides a matte black appearance, mild corrosion resistance (50–100 hr salt spray with oil), and improved lubricity. Applications: fasteners, gears, firearms components, hand tools.
Passivation per ASTM A967 removes free iron from stainless steel surfaces using nitric or citric acid, forming a chromium-rich oxide layer. No dimensional change or surface finish change. Enhances corrosion resistance for medical, food-grade, and chemical-exposure applications.
Spray painting applies 30–100 μm primer + topcoat layers to metals and plastics with RAL/Pantone color matching. Matte, satin, and high-gloss finishes available. UV-resistant clear coat optional for outdoor parts. Salt spray protection: 200–500 hours depending on primer system.
Mechanical polishing achieves Ra 0.012–0.1 μm mirror finish on aluminum, stainless steel, titanium, brass, and copper. Progressive buffing with 800 to 2000 grit followed by diamond paste. Applications: optical housings, decorative hardware, medical instruments, reflective surfaces.
Alodine (chromate conversion per MIL-DTL-5541) deposits a 0.25–1 μm chemical conversion layer on aluminum. Provides 168-hour salt spray corrosion protection and serves as an adhesion-promoting primer for paint or powder coat. No dimensional change. Maintains electrical conductivity — unlike anodizing.
CNC Machining Materials
Our CNC machining services support engineering-grade metals and plastics used for precision milled and turned parts.All materials listed below are supplied in machinable stock suitable for CNC processing.
Lightweight, corrosion-resistant, and highly machinable for precision and structural parts.
Grades
6061
6061-T6
6082
7075
7075-T6
2024
High electrical and thermal conductivity for conductive components.
Grades
C110
C101
Easy to machine with excellent surface finish for precision parts.
Grades
C360
C260
C280
Hard, wear-resistant material for tooling and high-stress components.
Grades
D2
A2
H13
High strength material for load-bearing and mechanical components.
Grades
1018
1020
1045
4140
EN8
EN19
Corrosion-resistant material for industrial, food, and medical components.
Grades
304
304L
316
316L
303
17-4 PH
Ultra-lightweight metal for weight-critical machined components.
Grades
AZ31
AZ91
High strength-to-weight ratio with excellent corrosion resistance.
Grades
Grade 2
Grade 5
Plastics
Impact-resistant plastic for enclosures and functional components.
Grades
ABS Natural
ABS Black
ABS Antistatic
High impact strength for protective and structural components.
Grades
Clear PC
Black PC
Rigid plastic with excellent optical clarity.
Grades
Clear PMMA
Black PMMA
Low friction and high dimensional stability for precision components.
Grades
POM-C
POM-H
Strong and wear-resistant plastic for mechanical parts.
Grades
PA6
PA66
Glass-Filled PA
Very low friction and high wear resistance for sliding components.
Grades
UHMW Natural
High-performance plastic for extreme temperature and chemical conditions.
Grades
Virgin PEEK
Glass-Filled PEEK
Carbon-Filled PEEK
Lightweight and chemical-resistant plastic for non-structural parts.
Grades
PP Homopolymer
Our Surface Finishing Prototype Manufacturing Capabilities
Provides injection molding for prototypes and custom parts, emphasizing expert support, competitive pricing, and faster production cycles.
Get reliable vacuum casting services for high-quality prototypes and production parts at competitive prices. XinCheng offers highly detailed casting parts with consistent quality.
Uses cutting, bending, and forming techniques to produce precision metal components suited for industrial, commercial, and manufacturing applications.
How Does XC Machining's Surface Finishing Process Work Step by Step?
Upload your STEP, STP, STL, or IGES file along with your surface finish specification. If you're unsure which finish to select, our engineers will recommend the optimal option based on your material, application, and cosmetic requirements.
Within 12 hours, our team reviews your part for masking requirements, coating thickness impact on critical dimensions, minimum feature size for finish penetration, and material compatibility. You receive a quote with finish type, Ra value, coating thickness, and lead time specified.
Your part is CNC machined, molded, or fabricated, then moved directly to our in-house finishing department. Surface treatment is applied per your specification with in-process quality checks at each stage.
Finished parts are inspected for Ra value (profilometer), coating thickness (gauge), adhesion (cross-hatch test), and visual quality under controlled lighting. Parts ship worldwide via DHL, FedEx, or UPS with inspection report and finish certificate.
Specialist Industries
Bring Your Designs to Life with XC Machining
- Expertise Shared Widely
- Market Reach Expanded
- Advanced Technology Integrated
- Collaborative Innovation Opportunities
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Prototyping Manufacturing FAQs
How Much Lead Time Does Surface Finishing Add to a Project?
Surface finishing typically adds 1–5 business days to total lead time depending on the process: bead blasting — 1 day, brushing/polishing — 1–2 days, anodizing Type II — 2–3 days, anodizing Type III — 3–5 days, powder coating — 2–3 days, painting — 2–3 days, electroplating — 3–5 days, passivation — 1–2 days. XC Machining applies finishes immediately after manufacturing in the same facility — no shipping delay between fabrication and finishing.
How Do You Choose the Right Surface Finish for Your Part?
Five factors determine finish selection: (1) base material — anodizing works only on aluminum, passivation only on stainless steel, (2) operating environment — outdoor parts need 500+ hr salt spray protection (powder coat or anodize), (3) cosmetic requirements — Ra 0.012 μm for mirror polish vs Ra 3.2 μm for matte, (4) regulatory compliance — MIL-spec for defense, ASTM A967 passivation for medical, (5) dimensional tolerance — coating thickness (5–120 μm) must be factored into critical dimensions.
Can XC Machining Match Specific Colors and Textures on Finished Parts?
Yes. XC Machining provides RAL and Pantone color matching on powder coating, spray painting, and anodizing (Type II). Custom textures include: brushed satin (Ra 0.4–0.8 μm), bead blasted matte (Ra 1.6–3.2 μm), and mirror polished (Ra 0.012–0.1 μm). We produce physical color and texture samples for approval before applying the finish to your production parts.
Does XC Machining Offer Environmentally Friendly Surface Finishes?
Yes. XC Machining offers: RoHS-compliant zinc plating (trivalent chromium passivation instead of hexavalent), citric acid passivation (acid alternative to nitric acid per ASTM A967 Citric 2), low-VOC water-based primers and paints, powder coating (zero VOC solvent-free process), and lead-free/cadmium-free electroplating. All finishes comply with EU REACH and RoHS directives.
How Much Does Surface Finishing Improve Part Durability and Corrosion Life?
Quantified durability improvements: bare aluminum corrodes in 50–100 hours salt spray → Type II anodize extends to 336–500 hours → Type III extends to 1,000+ hours. Bare mild steel corrodes in 24–48 hours → zinc plating extends to 200–500 hours → powder coating extends to 500–1,000 hours. Hard-coat anodizing increases aluminum surface hardness from Brinell 60 to Rockwell C 65–70, increasing wear life 10–50× depending on load.
What Is the Difference Between Anodizing and Powder Coating?
Anodizing grows oxide INTO the aluminum surface (5–80 μm deep) — it’s an integral part of the metal, not a separate layer. It works only on aluminum. Powder coating applies a polymer layer ON TOP of any metal surface (60–120 μm). Anodizing is harder (Rockwell C 65–70), thinner, and more wear-resistant. Powder coating is thicker, available in unlimited colors, and works on steel, aluminum, and stainless. Choose anodizing for aluminum parts requiring hardness and metallic appearance; choose powder coating for any metal requiring thick corrosion protection and custom color.
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