Aluminium CNC Machining: Material Guide and Supplier Tips
A practical guide to aluminium CNC machining: alloy selection, surface treatments, achievable tolerances and why Turkey is a competitive source for aluminium machined parts.
Published: · CNC Turkey
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Aluminium is one of the most widely used metals in CNC machining. Its weight of approximately one-third that of steel, combined with good thermal conductivity and corrosion resistance, makes it the preferred choice for lightweight structural parts, thermal management components and precision instrumentation.
In terms of machinability, aluminium offers significant advantages over steel: cutting forces are lower, tool wear is slower and higher cutting speeds can be used. This translates to shorter machining time per part — and therefore lower cost.
Common Aluminium Alloys: Which One to Choose?
Aluminium alloys offer different mechanical properties depending on composition and heat-treatment condition. The three most frequently used alloys in CNC machining are the EN AW-6060/6082 and 7075 groups.
✓EN AW-6060 / 6061: versatile, good machinability, medium strength. Widely used for general structural parts, extrusion profiles and housing components. T6 heat treatment significantly improves mechanical properties.
✓EN AW-6082 T6: higher strength than 6061, standard structural alloy in Europe. Good corrosion resistance for food industry and marine applications. Easy to machine in CNC turning and milling.
✓7075 T6: high strength-to-weight ratio, aerospace and defence applications. Lower corrosion resistance than 6082, higher cost. Evaluated for specialist applications.
✓Cast aluminium (AlSi series): CNC machining after casting for complex geometries. Typically used for housings and enclosures.
Surface Treatments for Aluminium CNC Parts
Aluminium parts often require surface treatment to improve corrosion resistance, add wear resistance or for aesthetic purposes. The most common surface treatments are:
✓Anodizing: creates an aluminium oxide layer to improve corrosion and wear resistance. Can be clear (natural), black or coloured. Choose between Type II (decorative) and Type III (hard anodizing) based on application requirements.
✓Chromate conversion (iridite/alodine): for applications requiring light corrosion protection and electrical conductivity. Thinner coating than anodizing; minimal dimensional change.
✓Painting (powder coating / wet paint): decorative and protective. Greater dimensional impact than anodizing; masking may be required on tight-tolerance surfaces.
Achievable Tolerances in Aluminium CNC Machining
Aluminium has a different thermal expansion coefficient compared to steel. This must be taken into account in precision measurement. However, IT7 tolerances for aluminium are routinely achievable in a well-equipped CNC facility.
Care is needed regarding the dimensional effect of anodizing: Type II anodizing typically adds 5–25 µm thickness per surface. For tight-tolerance fits or surfaces, specify this at the quotation stage; post-anodize machining or masking may be required.
Sourcing Aluminium CNC Parts from Turkey
Aluminium raw material sourcing in Turkey is strong; EN AW-6060, EN AW-6082 T6 and 7075 T6 are available as profiles and bar stock. Under the EU Customs Union, aluminium machined parts enter Europe with zero tariff.
Anodizing and other aluminium surface treatments can be coordinated through a qualified supplier network. Specifying alloy, heat-treatment condition (T6 etc.), surface treatment requirement and pre- or post-treatment dimensional criticalities at the quotation stage ensures the most accurate price and lead time.
FAQ
Frequently asked questions
Which aluminium alloy is recommended for CNC machining?
For general-purpose structural parts, EN AW-6082 T6 (European standard) or 6061 T6 is preferred. Where lightweight and high strength are critical, 7075 T6 can be considered. For cast geometries, the AlSi series is suitable. Alloy selection should be made based on application, mechanical requirements and surface treatment.
Does anodizing affect the part tolerance?
Yes. Type II anodizing typically adds 5–25 µm per surface, which can result in a total dimensional change of 10–50 µm on diameter dimensions. For precision fits or tight-tolerance surfaces, post-anodize machining or masking should be planned and specified at the quotation stage.
Is EN 10204 3.1 material certificate available for aluminium CNC parts from Turkey?
EN 10204 3.1 material certificate can be supplied for aluminium parts when requested and agreed at the quotation stage. Alloy, form (profile/bar stock), sourcing and purchase conditions affect availability. For orders requiring certification, include this in your RFQ.
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