Anodize Finish

The Macfab team provides one-stop solutions to the challenges of manufacturing and plating. We deliver parts ready for our customers’ immediate use, with anodizing when needed.

Anodizing aluminum is an electrochemical reaction that applies a layer of material onto the aluminum part. The advantages of anodizing include:

  • Increased corrosion resistance
  • Increased wear resistance
  • Lowers electrical conductivity
  • Lasting color

It can also be applied to magnesium and titanium parts.

The Types of Anodizing

PropertiesType-I
(Chromic Acid)
Type-II
(Sulphuric Acid)
Type-III
(Hard Anodize)
ApplicationsDecorativeDecorativeCorrosion resistance
Corrosion ResistanceGoodGoodExcellent
Coating Thickness0.08-0.25 µm2.54-25 µm12.7-80 µm
Wear ResistancePoorModerateExcellent
PorosityLowModerateHigh
Environment ImpactNoYesYes
AppearancePrimary coatClear or coloursHard clear or black

The process of anodizing aluminum requires the part to be made undersized to account for the addition of anodizing. Choosing a vendor that delivers the part fully processed reduces potential issues stemming from compensating for the part growth due to the anodizing process.

In anodizing, a clean part is placed in the prepared solution. The aluminum part is positively charged, making it the anode and a negative charge is applied to a metal plate in the solution. The current passing from the plate to the aluminum workpiece bonds chemically to the aluminum part.

Anodizing can be done as a hard coat (Type III). This offers high corrosion protection and improves wear performance for mechanical parts exposed to high frictional heating. The anodizing controls the thickness of the aluminum oxide barrier layer. Aluminum oxide is nearly as strong as a diamond. While aluminum is most commonly anodized, it is also possible to apply this process to magnesium and titanium.

The anodizing process also allows for colours to be absorbed into the chemical structure of the part. Short of applying a grinding mechanism on the part, the colour will not peel or scratch away from the part.

Design considerations for a successful part:

  • Remember to account for anodized growth for tight tolerance connections
  • Corners will have a minimum radius of 0.020”
  • If the part has esthetics requirements, a deburring or polishing operation should be done before anodizing
  • Choose a location that does not require anodizing, as the part must be fixtured to the electrode to complete the process

Our anodizing services complement our full turnkey manufacturing approach, exclusively available when you leverage Macfab for CNC machining. It's important to note that these services are an inherent part of our comprehensive manufacturing solution and are not provided as standalone offerings.