CNC machining + coordinated finishing

Anodizing for CNC-Machined Aluminum Parts

We plan anodizing alongside machining so color, corrosion and wear requirements work with the finished dimensions—not against them. We review alloy, application, film thickness, masking and fit dimensions before confirming a process route.

Request a combined quote Explore our approach

±0.01 mm

Listed machining precision on most features

5–75 µm

Typical Type II and hard-coat film ranges

One route

Coordinated machining, finishing and inspection

CNC-machined aluminum component with an anodized surface

We consider the machined surface and the specified finish together, since tool marks and alloy composition remain visible through anodizing.

Plan before finishing

What anodizing changes on a machined part

Anodizing forms a controlled oxide layer through an electrolytic process. It becomes part of the aluminum surface rather than a paint or plated layer, and it can be sealed or dyed to meet the specification.

01 / Dimensions

Allow for film build

The film grows both into and outward from the surface. For typical decorative or corrosion-protection film, the finished dimension on each anodized surface increases by roughly half the film thickness. Hard anodizing builds more.

02 / Performance

Balance wear and impact

Hard anodic films can improve wear resistance on sliding and clamping surfaces. They are brittle at edges and can crack under impact, so geometry and use matter.

03 / Appearance

Finish starts at machining

Tool marks, machining direction and alloy composition show through the finished color. A change in alloy or surface finish can change the appearance between parts.

Our approach: we set machining allowances with the finish in mind.

A part that measures correctly before anodizing can miss fit or function after coating. We review critical bores, outside diameters and interfaces against the specified film class and thickness before cutting the first article.

Material selection

Alloy and temper influence the result

We ask for the exact alloy and temper, not only the alloy family. If the drawing does not specify them, we recommend confirming the material before cutting, since a late change can affect both finish and machining plans.

6061 and 6082

Common machining grades for anodized housings and brackets. They generally support consistent clear and colored finishes.

7075

Often selected for strength and can be anodized, though color uniformity is usually less predictable.

2xxx, 4xxx and cast alloys

Higher copper or silicon content can produce darker, less uniform color or a rougher film. Casting porosity can also affect color and sealing.

Specify the finish

Choose by appearance, protection and wear

A useful specification identifies color, film class, thickness range and performance requirement. Select a finish below to review typical applications and planning considerations.

Final feasibility depends on alloy, geometry, masking, sealing and the applicable drawing or performance standard.

Typical film thickness: 5–25 µm

Clear, natural or colored finish

Clear or natural Type II is commonly chosen for general corrosion protection and a metallic look. Colored Type II can support identification or styling across part families. Dark colors may show surface defects more clearly, making the machining finish important.

We review the required color, sealing and corrosion target together with alloy and masking details before confirming the route.

Machining and inspection

How we plan for fit after anodizing

We calculate allowances from the film class and thickness range, then review critical dimensions on the drawing before the first article is made. The direction of the allowance depends on whether a feature is internal or external.

Define critical interfaces

We identify bores, sliding shafts, press fits, close-clearance holes and external diameters that must meet final dimensions.

Plan masking and threads

Threads, electrical contacts, bearing seats and reference faces may need masking. Threads may instead be cut after anodizing, depending on thread class.

Control the machined surface

We review surface roughness, machining direction, edge breaks and burrs. Small edge breaks or radii can improve consistency, especially for hard anodizing.

Verify the finished part

Where required, we measure critical features before and after finishing, and after sealing when specified, so dimensional change is documented.

Machining capabilities

We machine aluminum on 3-axis and 4-axis CNC milling centers, CNC lathes, turn-mill machines and Swiss-type lathes. Listed precision is ±0.01 mm on most features.

Measurement resources

Our inspection resources include a CMM, 2D optical measuring systems, height and concentricity instruments, micrometers, calipers, gauge blocks and pin gauges. We check thread fit with M1.0 to M16 thread ring and plug gauges, and can check specified roughness with a surface roughness tester.

For film thickness, we use a coating thickness gauge on valid test surfaces or witness areas and can request the finishing partner’s thickness certificate. We agree inspection records—including first article reports, dimensional tables and measurement methods—before production starts.

Coordinated supplier service

We coordinate anodizing with qualified finishing partners

We do not run anodizing in-house. Our finishing partners carry out the anodizing, and we coordinate the handoff between machining and finishing. We confirm alloy, color, film class, thickness range, masking and sealing requirements with the partner before quoting.

We include finishing cost and lead time in the overall quotation, with machining, anodizing and inspection shown separately. If you have an approved finishing supplier, we can work with them when process requirements and documentation are shared in advance.

Where anodized CNC aluminum fits

Industrial equipment: housings, covers, brackets and mounting plates needing corrosion resistance and consistent appearance.
Electronics and instrumentation: enclosures and heat-dissipating parts with a specified clear or dark finish.
OEM programs: parts differentiated by color, plus robotics and automation components where low weight and a durable surface are important.
Wear components: guides and clamping parts that may benefit from hard anodizing.

When we recommend a closer review

Very tight press fits, unmasked threads, porous cast aluminum, or exposure to strong alkaline or chloride environments can affect suitability. A sealed film with a defined performance target or another surface treatment may be needed. We review these conditions rather than promise an unverified result.

Prepare your RFQ

Send the details that shape the process

Share your aluminum grade, surface standard, color and drawing. We will review machining allowances and the finishing route, then return a combined quotation for machining and surface treatment.

Get a machining and finishing quote

RFQ checklist

Drawings

PDF or STEP with dimensions, tolerances, thread specifications and surface-finish callouts.
Material

Aluminum alloy and temper, or the specified material standard.
Finish specification

Type II or Type III, named standard, color, film thickness range and sealing requirement.
Masking and fit

Features that must stay uncoated, critical interfaces and close-fit dimensions.
Quantity and schedule

Prototype, repeat order or production run, with the required delivery schedule.
Inspection records

First article inspection, film thickness records or dimensional reports.

Request a coordinated quote

Let’s review your aluminum part and finish requirements

Send us the alloy grade, surface standard, color and drawing. We’ll assess the machining allowances, masking and coordinated finishing route for your application.