3D Hubs is now Hubs - custom parts manufacturing for engineers worldwide
Our surface finishing capabilities
Use Hubs as your one-stop solution for both manufacturing and surface finishing of your custom CNC machined parts, reducing the risk of production.
Do you need lettering logos or custom tags? Take a look at our part marking service here.
Our standard surface finishes
Here is a list of standard surface finishes. For custom surface finishes such as electroplating or polishing, please contact sales@hubs.com.
As machined
Our standard finish is “as machined” finish. It has a surface roughness of 3.2 μm (126 μin). All sharp edges are removed and parts are deburred. Tool marks are visible.
| Requirement | Specification |
|---|---|
| Cosmetic availability | Non-cosmetic |
Smooth machining (1.6 Ra μm/64 Ra μin)
A finishing CNC machining operation can be applied to the part to reduce its surface roughness. The standard smoothing surface roughness (Ra) is 1.6 μm (64 μin). Machine marks are less evident but still visible.
| Requirement | Specification |
|---|---|
| Cosmetic availability | Non-cosmetic |
Bead blasted
Bead blasting adds a uniform matte or satin surface finish on a machined part, removing the tool marks. This is used mainly for visual purposes and comes in several different grits which indicate the size of the bombarding pellets. Our standard grit is #120.
| Requirement | Specification |
|---|---|
| Grit | #120 |
| Color | Uniform matte of raw material color |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic on request |
Bead blasted + Anodizing type II (Matte)
Parts are bead blasted to #120 grit and then anodized (type II). Ideal for increasing the corrosion resistance of the part. Results in naturally matte colours. For glossy colours, please select the brushed anodizing option.
| Requirement | Specification |
|---|---|
| Surface preparation | Bead blasted with glass beads grit #120 |
| Tolerances | General dimensional tolerances apply after anodizing |
| Thickness | 4 - 8 μm (clear), 8 - 12 μm (color) |
| Gloss Units | 2 - 10 GU |
| Color | Black, clear or any RAL code or Pantone number |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic on request |
Brushed + Anodizing type II (Glossy)
Parts are brushed and then anodized type II. Ideal for increasing the corrosion resistance of the part. Typically results in a glossy color.
| Requirement | Specification |
|---|---|
| Surface preparation | Brushed with grit #400 |
| Tolerances | General dimensional tolerances apply after anodizing |
| Thickness | 4 - 8 μm (clear), 8 - 12 μm (color) |
| Gloss Units | 10 - 60 GU |
| Color | black, clear or any RAL code or Pantone number |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic on request |
As machined + Anodized type III (Hardcoat)
The anodizing type III coating is applied directly to a surface as machined (no other mechanical finish applied). Type III anodizing provides excellent corrosion and wear resistance, suitable for functional applications.
| Requirement | Specification |
|---|---|
| Surface preparation | "As machined", cleaned and de-greased |
| Tolerances | General dimensional tolerances met before anodizing |
| Thickness | 35-50 μm |
| Color | Black or natural |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Non-cosmetic |
Powder coating
Powder coating is a strong, wear-resistant finish that is compatible with all metal materials.
| Requirement | Specification |
|---|---|
| Tolerances | Met before process |
| Thickness | 50-150μm |
| Color | Black or any RAL code or Pantone number |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Non-cosmetic |
Brushed + Electropolished (Ra0.8µm, 32µin)
Electropolishing is an electrochemical process used to clean metallic surfaces and reduce micro-roughness of stainless steel parts. Useful to remove a thin (up to 10μm) layer of material and improve surface finish.
| Requirement | Specification |
|---|---|
| Surface preparation | Brushed |
| Color | Natural metal color |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic by default |
Black oxide
Applicable on steels, black oxide is a Conversion coating used to improve corrosion resistance and minimize light reflection.
| Requirement | Specification |
|---|---|
| Surface preparation | "As machined", cleaned and de-greased |
| Thickness | 0-30μm |
| Color | Black. |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Non-cosmetic |
Chromate conversion coating (Alodine/Chemfilm)
Chromate conversion coating is used to increase the corrosion resistance of aluminium and aluminium alloys while maintaining their conductive properties.
| Requirement | Specification |
|---|---|
| Surface preparation | "As machined", cleaned and de-greased |
| Color | Clear |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Non-cosmetic |
Brushing
Brushing is produced by polishing the metal with grit resulting in a unidirectional satin finish. Not advisable for applications where corrosion resistance is required.
| Requirement | Specification |
|---|---|
| Surface roughness | Ra 1.2μm / Ra 47μm |
| Grit | #400-600 |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic on request |
Polishing
Parts are manually polished in multiple directions. Surface is smooth and slightly reflective.
| Requirement | Specification |
|---|---|
| Surface roughness | Ra 0.8μm / Ra 32μm |
| Part masking | Indicate masking requirements in technical drawing |
| Cosmetic availability | Cosmetic by default |
Cosmetic Finishes
For parts that look as good as they perform. We're dedicated to ensuring the surface finishes of your parts meet your cosmetic requirements and we therefore require extra measures to guarantee optimal quality and results.
What is a cosmetic finish?
When adding a surface finish to your part, you choose whether the finish has a merely functional purpose or whether it should also serve an aesthetic purpose.
Parts that serve both functional and aesthetic purposes are deemed cosmetic.
The production of cosmetic parts require extra measures to minimize defects such as hang marks, light scratches and other minor imperfections.
For all of our available finishes, we have categorized them by their cosmetic availability:
Non-cosmetic
Primary machining marks will still be visible
- As machined
- Smooth machining
- Chromate Conversion Coating
- Anodized type III (Hardcoat)
- Powder coating
- Black oxide
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
Cosmetic by default
These finishes will not have the option to be non-cosmetic.
- Polishing
- Brushed + Electropolished
What differences are there between cosmetic and non-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
- Around +10% price increase
Defining an A and a B side
The processes of applying surface finishes will unavoidably incur some defects such as hang marks, for instance. However, these can be focussed to a certain surface or area of your part to allow the rest of your part to be defect free.
This can be achieved by defining an A-side and a B-side in the technical drawing of your part:
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.
Surfaces declared as the A-side will be defect free while B-side surfaces will have a slightly more tolerating acceptability criteria:
| Defect type | Primary surface (A-side) | Secondary surface (B-side) |
|---|---|---|
| Scratches, stains, blemishes | Not allowed | Not allowed |
| Hanging marks | Not allowed | Minor hanging marks |
| Other minor defects | Not allowed | Up to 2 minor defects |
Cosmetic Acceptability Criteria
For all cosmetic parts produced by our manufacturing partners, we have devized an acceptability criteria that will be followed:
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.
Conditions
Upon receiving your part at our quality control facilities, care will be taken to visually inspect the surface quality of each part with the following conditions:
- Distance: 50cm ±10cm 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)
See our video: Cosmetic vs Non-cosmetic Finishes Explained
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