As-machined
The default finish straight off the machine, typically Ra 1.6–3.2 µm with light visible tool marks.
Process · CNC machining
Finishing solutions
Surface finishing for your parts
A broad range of finishes to improve the performance and appearance of your parts. Each is selected by material, function and appearance requirement - so the treatment suits its application.
Anodizing
Type II and hard-coat anodizing create a protective oxide layer on aluminium for corrosion resistance, wear resistance and color.
Process · CNC / die casting
Polishing
Mechanical polishing reduces roughness to a bright, smooth or mirror surface for cosmetic and high-spec parts.
Process · CNC / die casting
Bead / sand blasting
Blasting media give a uniform matte texture, removing tool marks and evening the surface before or after coating.
Process · CNC / die casting
Tumbling / deburring
Vibratory tumbling deburrs and smooths small parts in bulk, rounding sharp edges and evening the surface.
Process · CNC / die casting
Specify your finish, color, gloss and any masking requirements on your drawing, or describe the function the surface must perform and we will recommend a suitable treatment at DFM review.
Request a finishing quote
Inspection acceptance
Appearance inspection & acceptance standards
Every finished surface is inspected under controlled conditions against clear acceptance criteria - so coverage, texture, gloss and color stay consistent across the whole batch.
- Anodized, plated or coated surfaces match the agreed color reference or approved sample within a defined tolerance.
- Brushed and grained finishes run in one consistent direction at a uniform grit across the part.
- Cosmetic surfaces are checked for scratches, pits, dents, blisters and other defects against agreed acceptance criteria.
- Gloss and texture stay within the agreed range, checked against a master sample before release.
Visual inspection standard
- Parts are inspected under controlled lighting to assess batch-to-batch consistency against the approved sample.
- Critical cosmetic surfaces are viewed at a defined distance and angle against the approved sample.
- Surfaces must be free of fingerprints, oil, watermarks and residue, and show no undesired discoloration.
- Packaging is checked at final inspection to keep the finish stable and protected in transit.
The basics
What is surface finishing?
Surface finish describes a part’s outer surface after machining, whether left as-machined or treated to change its texture, hardness, corrosion resistance or appearance. Surface roughness (Ra) is one common measure, while the finish also affects how a part seals, wears, conducts, reflects light and resists its environment.
On precision parts, the finish is part of the specification, not an afterthought. The right treatment can improve functional performance and help meet dimensional and assembly requirements, while providing the appearance and protection the application needs.
Common questions
Surface finishing FAQs
How do I choose the right finish for my part?
Start from the surface's job — corrosion protection, wear resistance, conductivity, appearance or marking — plus the base material and any color or gloss target. Tell us the function, or specify the finish on your drawing, and we'll recommend a suitable treatment at DFM review.
Are all finishes suitable for every material?
No — each finish suits particular metals. Anodizing and chromate conversion are for aluminium; passivation is for stainless; black oxide and powder coating suit steel. We match the treatment to your base material.
Can I apply more than one finish to a part?
Yes. Processes are often combined — for example bead blasting before anodizing, or plating followed by laser marking. We sequence treatments so each step supports the next.
Will finishing affect dimensional accuracy?
Some finishes add a measurable layer — hard anodize and plating in particular. We account for build-up at quoting and apply machining allowance or masking so critical dimensions stay in tolerance.
Can these finishes meet RoHS / REACH requirements?
Yes. Where required, finishes can be selected and documented to meet RoHS and REACH, with compliance certificates provided on request.
How do I maintain a finished surface?
Most finishes need only gentle cleaning with a soft cloth and mild detergent. Avoid abrasives on anodized, brushed and polished surfaces. We can advise care guidance for a specific finish.
How long does finishing add to lead time?
It depends on the process and whether it runs in-house or with a coordinated partner — typically a few days. The finishing step is included in the lead time we confirm at quoting.