CNC Surface Finish Guide
CNC Surface Finish Guide for Custom Machined Parts
Compare common CNC surface finishing options by material fit, visual result, dimensional impact, roughness target, inspection method, and RFQ information needed before production planning.
Finish selection before quotation
What This Guide Helps You Decide
Surface finish affects how a CNC machined part looks, fits, resists corrosion, handles wear, conducts electricity, insulates, seals, and passes inspection. JADE-CNC reviews finish requirements together with material, geometry, machining marks, masking areas, tolerance impact, and cosmetic surfaces.
This guide is a practical reference for RFQ preparation. Actual finish capability is confirmed according to drawing requirements, material grade, part geometry, coating process, escopo de inspeção, and project quantity.
RFQ review note
For faster review, include finish name, color, visible faces, masking areas, roughness target, coating thickness if required, inspection method, and any functional surfaces that must remain controlled after finishing.
Surface function
Start With the Function of the Surface
Define matte, glossy, brushed, polished, black, natural, or color-matched surfaces and identify visible cosmetic faces.
Confirm whether the part faces humidity, salt, outdoor exposure, chemicals, or cleaning fluids.
Mark sliding surfaces, mating faces, threaded areas, and features where coating buildup may affect fit.
Clarify conductive, insulating, grounding, or masking requirements before anodizing, revestimento, or plating.
Review coating thickness, masking, edge condition, hole fit, and tolerance zones before final finish approval.
Specify whether roughness check, coating thickness record, visual approval, or dimensional report is required.
Common finishing options
Surface Finishing Options JADE-CNC Commonly Reviews
| Finish Option | Typical Use | Materials Often Reviewed | Key RFQ Details |
|---|---|---|---|
| Anodização | Color, resistência à corrosão, and improved surface durability for aluminum parts. | Alumínio 6061, 7075, 2024, 6082 | Color, Type II or hardcoat, masking areas, visible faces, thickness if controlled. |
| Jateamento de contas | Uniform matte appearance and reduced machining marks before anodizing or cosmetic review. | Alumínio, aço inoxidável, latão | Cosmetic faces, protected dimensions, acceptable surface texture, before/after finish condition. |
| Black Oxide | Dark surface appearance and mild corrosion protection for steel components. | Carbon steel, alloy steel, aço para ferramentas | Required appearance, post-treatment oiling, threaded areas, mating surfaces. |
| Passivação | Cleaning and corrosion-resistance support for stainless steel machined parts. | Aço inoxidável 304, 316, 17-4PH | Grau do material, standard if specified, cleanliness needs, documentation requirement. |
| Polimento / Brushing | Directional or reflective appearance for visible metal surfaces. | Aço inoxidável, alumínio, latão | Grain direction, visible side, roughness target, edge protection, sample approval if needed. |
| Pintura / Revestimento em pó | Color, aparência, insulation, and protective coating for housings or panels. | Alumínio, steel, selected assemblies | Color code, coating thickness, masking, threaded holes, adhesion or cosmetic requirement. |
Dimensional and inspection planning
How JADE-CNC Reviews Finish Impact
Drawing Review
Check finish symbols, notes, critical dimensions, GD&T, visible faces, tópicos, buracos, and mating surfaces.
Material Match
Confirm whether the requested finish is suitable for aluminum, aço inoxidável, cobre, latão, steel, or engineering plastic.
Masking Plan
Identify areas that must stay conductive, uncoated, threaded, dimensionally controlled, or cosmetically protected.
Inspection Scope
Plan visual checks, roughness review, coating thickness record, CMM report, or finish approval reference when required.
RFQ checklist
Information to Share With Your Drawings
Anodização, hardcoat anodizing, black oxide, passivação, polimento, bead blasting, pintura, chapeamento, or powder coating.
Natural, black, clear, matte, gloss, brushed direction, cosmetic faces, and sample approval expectation.
Threads, buracos, bores, sealing faces, electrical contact zones, mating faces, and surfaces that need masking.
Coating thickness, Ra target, pre-finish dimensions, after-finish dimensions, and acceptance tolerance.
Visual inspection, dimensional report, CMM report, coating check, roughness check, CoC, or customer format.
Outdoor exposure, salt, heat, wear, chemical contact, cleaning fluid, insulation, conductivity, or assembly condition.
Need a Finish Review Before Quotation?
Send drawings, material grade, finish requirements, cosmetic expectations, and inspection needs. JADE-CNC will review manufacturability before machining and finishing planning.
CNC Surface Finishing FAQ
Common CNC surface finishes include anodizing, hardcoat anodizing, bead blasting, polimento, brushing, passivação, black oxide, chapeamento, pintura, powder coating, laser marking, and tumbling.
Start with the part function. Appearance, resistência à corrosão, resistência ao desgaste, electrical conductivity, insulation, vedação, limpeza, and assembly fit can all affect the finish choice.
Sim. Anodizing and hardcoat anodizing can add coating thickness and may affect holes, tópicos, mating faces, and tight tolerance areas. Controlled dimensions should be marked clearly on the drawing.
Masking should be considered for threads, buracos, sealing faces, electrical contact areas, bearing surfaces, mating faces, and any feature that must remain uncoated or dimensionally controlled.
Sim. Passivation is commonly used for stainless steel parts to support corrosion resistance and cleanliness. Material grade and documentation requirements should be confirmed when needed.
Some plastic parts can be polished, bead blasted, vapor polished, painted, or laser marked depending on the material. The finish method should match the plastic type and appearance requirement.
Bead blasting creates a more uniform matte surface, while polishing produces a smoother or more reflective appearance. The choice depends on cosmetic expectation, material, and visible surface requirements.
Coating thickness can affect hole fit, thread function, sealing surfaces, mating dimensions, and assembly clearance. Drawings should identify areas where thickness must be controlled or avoided.
Important checks may include visual appearance, color consistency, surface roughness, coating thickness, masking result, critical dimensions after finishing, and customer-required documentation.
Send the CAD file, 2D drawing, material grade, finish name, color or appearance target, masking areas, roughness target, coating thickness requirement, cosmetic faces, and inspection record needs.