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Surface finishing service

The easiest way to source your custom parts, with 15+ surface finishing options. Get your parts bead blasted, anodized, or powder coated.

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Name

Service

Applicable to

Machining marks

Cosmetic availability

Tolerances

As machined  

CNC machining, Sheet metal fabricat ion

Metals, Plastics

Visible, light surface scratches 

No

Tolerances are not affected

Smooth machining

CNC machining

Metals, Plastics

Visible, light surface scratches

No

Tolerances are not affected

Fine machining

CNC machining

Metals

Slightly visible

No

Tolerances are not affected

Polishing

CNC machining

Metals

Removed on primary surfaces

Always cosmetic

Met after polishing

Bead blasting

CNC machining, Sheet metal fabrication

Metals

Removed for non-cosmetic, removed on primary surfaces for cosmetic  

On request

Not affected except for specific features* 

Brushing

CNC machining, Sheet metal fabrication

Metals

Reduced for non-cosmetic, removed on primary surfaces for cosmetic 

On request

Met after brushing

Anodizing Type II

CNC machining, Sheet metal fabrication

Aluminum

Reduced for non-cosmetic, removed on primary surfaces for cosmetic 

On request

Met after anodizing

Anodizing Type III

CNC machining, Sheet metal fabrication

Aluminum

Visible under anodizing

No

Met after anodizing

Black oxide 

CNC machining, Sheet metal fabrication

Copper, Stainless steel, Alloy steel, Tool steel, Mild steel

Visible

No

Met after coating

Chromate conversion coating

CNC machining, Sheet metal fabrication

Aluminum

Visible

No

Met after coating

Electroless nickel plating

CNC machining

Mild steel, Aluminum, Stainless steel

Reduced but visible

No

Met after electroless nickel plating

Powder coating

CNC machining, Sheet metal fabrication

Metals

Removed

No

Met before powder coating

Brushed + electropolishing

CNC machining

Stainless steel

Removed on Primary surfaces

Always cosmetic

Met after electropolishing

Vapor smoothing

3D printing

Plastics

Surface gets a smooth glossier appearance

No

Met before vapor smoothing

Cosmetic finishes

Surface finishes can serve either a functional or aesthetic purpose. Surface finishes that serve both purposes are deemed cosmetic finishes, and are used for cosmetic parts. Producing cosmetic parts requires additional measures to minimize defects such as hang marks and scratches from tools.

Parts with non-cosmetic finish
Non-cosmetic

Primary machining marks will still be visible

  • As machined
  • Smooth machining
  • Fine machining
  • Chromate Conversion Coating
  • Electroless Nickel Plating
  • Anodized type III (Hardcoat)
  • Powder coating
  • Black oxide
Example of parts with cosmetic surface finish on request
Cosmetic on request

Finishes can be either cosmetic or non-cosmetic as per request

  • Brushed + Anodizing type II
  • Bead Blasted + Anodizing type II
  • Bead Blasted
  • Brushed
Example of part with default cosmetic surface finish
Cosmetic by default

These finishes will always serve a cosmetic function

  • Brushed + Electropolished
  • Polishing

Defining an A and a B side

Surface finishing often leaves aesthetic defects on your parts, such as hang marks for anodizing. Defining an A- and a B-side in your design will ensure that the most important areas of your part remain free of defects.

In this image you can see how you can define an A-side and a B-side in your technical drawing:
A side: Indicates the most aesthetically important surface, typically the visible side of your product.
B side: Indicates the side that is not aesthetically important, typically the side hidden from visibility after assembly.

For the primary surface (A-side) of your part, we guarantee defect-free production. In contrast, secondary surfaces (B-side) may be machined with hanging marks and other minor defects. B-side surfaces, like the rest of your part, will be free of scratches, stains and blemishes.

Will my part have Primary surface
(A-side)
Secondary surface
(B-side)
Scratches, stains, blemishes No No
Hanging marks No Minor hanging marks
Other minor defects No Up to 2 minor defects

Cosmetic Acceptability Criteria

All cosmetic parts produced by Protolabs Network follow our Cosmetic Acceptability Criteria:

Consistency requirement illustration
Consistency requirements

Each part must be visually consistent across the same batch, meaning:

  • Same grit must be used across parts for sanding or brushing
  • Brush marks must be in the same direction**
  • Color must be consistent to the same pantone when parts are placed next to each other
  • Gloss units must be consistent across the batch

*** Manual brushing marks will be as unidirectional as possible. Please note that for rounded geometries, brushing marks may not be entirely unidirectional.*

Observation condition illustration
Visual inspection conditions

The surface quality of every part must meet the following conditions:

  • Distance: 50cm ±10cm (19,7 in ± 3,9 in) with a 10/10 vision (or corrected)
  • Incidence angle: Approximately 45º in all directions
  • Lighting conditions: 500-1000 Lux, color 3300-5300 Kelvin (neutral white)

What do you need to know about cosmetic finishes?

  • Cosmetic finishes will follow our Cosmetic Acceptability Criteria

  • Parts will have guaranteed consistency across the batch

  • Batch will be inspected as per AQL level II

  • There will be around a +10% price increase

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